Groundwater Quality Standards 15A NCAC 02L .0202

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STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY

REPORT OF PROCEEDINGS TO THE NORTH CAROLINA
ENVIRONMENTAL MANAGEMENT COMMISSION FOR
PROPOSED REVISIONS TO THE 15A NCAC 02L .0202
GROUNDWATER QUALITY STANDARDS RULES

PUBLIC HEARING
Date: February 2, 2021, 6:00 PM
Location: Online Public Hearing, accessible through WebEx
NC Register: Publication of Notice of Environmental Management Commission intention to
amend the 15A NCAC 02L .0202 rule given in accordance with G.S. 150B-21.2.
Volume 35, Issue 14, Pages 1524-1610, January 15, 2021

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TABLE OF CONTENTS
INTRODUCTION
BACKGROUND
SUMMARY OF PROPOSALS
REGULATORY IMPACT ANALYSIS
PUBLIC HEARING PROCESS
SUMMARY OF ORAL AND WRITTEN COMMENTS AND RESPONSES TO COMMENTS
Total PFOS and PFOA Standard
Different Values
Regulate PFAS as a Class
Current PFOA IMAC
Other PFAS Comments
Additional Comments
Support of Proposed Changes
Proposed Additions and Changes
Regulatory Impact Analysis
Other Comments
RECOMMENDATIONS
ATTACHMENTS AND SUPPORTING DOCUMENTATION
A. Secretaries’ Science Advisory Board Summary Statement on Proposed PFOA and
PFOS Groundwater Quality Standard
B. OSBM Approved 15A NCAC 02L .0202 Regulatory Impact Analysis
C. Public Hearing Announcement
D. Hearing Officer’s Remarks
E. Public Hearing Division of Water Resources Staff Presentation
F. Public Hearing Registered Attendees
G. Public Hearing Speakers
H. Written Comments Received
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I. Updated PFOA and PFOS Summary Documents
J. NC DWR and Hearing Officer’s Recommended 02L .0202 Rule Text

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I. INTRODUCTION
This report is the official record of the proceedings related to the North Carolina Department of Environmental Quality Division of Water Resources’ and the Environmental Management Commission’s proposal to revise the Groundwater Quality Standards in 15A NCAC 02L .0202. This report includes oral and written comments received during the public hearing and public
comment period, relevant attachments, and the final recommendation of the Hearing Officer as to the proposed revisions to the Groundwater Quality Standard Rules for consideration by the North Carolina Environmental Management Commission. Table of Abbreviations and Acronyms
The abbreviations and acronyms used in this report are defined as follows:
Abbreviation Meaning
02L .0202 15A NCAC 02L .0202 Groundwater Quality Standards
APA Administrative Procedures Act
ATSDR Agency for Toxic Substances and Disease Registry
CASRN Chemical Abstracts Service Registry Numbers
Department Department of Environmental Quality
DEQ Department of Environmental Quality
Director Director of the Division of Water Resources Division Division of Water Resources
DWR Division of Water Resources
EMC Environmental Management Commission
EPA U.S. Environmental Protection Agency
GWWMC Groundwater and Waste Management Committee
IMAC Interim Maximum Allowable Concentration
IRIS U.S. EPA Integrated Risk Information System
µg/L Micrograms per liter
ng/L Nanograms per liter
NC North Carolina NCAC North Carolina Administrative Code
NCGS North Carolina General Statutes
NPDES National Pollution Discharge Elimination System
OSBM Office of State Budget and Management
PFAS The family of per- and poly-fluorinated substances
PFOA Perfluorooctanoic acid
PFOS Perfluorooctane sulfonic acid ppb parts per billion
ppt parts per trillion
PQL Practical Quantitation Limit
RfD Reference Dose
RIA Regulatory Impact Analysis
RSC Relative Source Contribution
SSAB NC Secretaries’ Science Advisory Board
Staff Staff of the Division of Water Resources
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II. BACKGROUND
Groundwater Quality Standards for the protection of groundwaters of the state are established by 15A NCAC 02L .0202. They are the maximum allowable concentrations resulting from any discharge of contaminants to the land or waters of the state, which may be tolerated without creating a threat to human health or which would otherwise render the groundwater unsuitable
for its intended best usage as an existing or potential source of drinking water supply for humans. Every three years the State is required by 15A NCAC 02L .0202(g) to review its groundwater water quality standards and interim maximum allowable concentrations to determine if changes are needed and, if necessary, to make those changes. Revision of these standards is needed to ensure that they contain the most recent health and toxicological information.
15A NCAC 02L .0202(c) states that any person may petition the Director of the Division of Water Resources to establish an Interim Maximum Allowable Concentration (IMAC) for a substance for which a standard has not been established under the rule. The last periodic review performed by Division staff focused on the IMACs that have been established under 02L
.0202(c). Staff reviewed the toxicological research and literature in accordance with 15A NCAC 02L .0202 to account for new information, new data, or reexaminations of existing data. Current regulations establish groundwater quality standards as the least of the six criteria contained in 15A NCAC 02L .0202(d) (1) – (6):
1. Systemic threshold concentration calculated as follows: [Reference Dose (mg/kg/day) x 70 kg (adult body weight) x Relative Source Contribution (0.10 for inorganics; 0.20 for organics)]/[2liters/day (avg. water consumption)]; 2. Concentration which corresponds to an incremental lifetime cancer risk of 1x 10-6;
3. Taste threshold limit value; 4. Odor threshold limit value; 5. Maximum contaminant level; or 6. National secondary drinking water standard.
Further, Paragraph 15A NCAC 02L .0202(e) requires that the following references, in order of preference, be used in establishing concentrations of substances which correspond to levels described in Paragraph (d) above: 1. U.S. EPA Integrated Risk Information System (IRIS). 2. Health Advisories (U.S. EPA Office of Water).
3. Other health risk assessment data published by U.S. EPA. 4. Other relevant, published health risk assessment data and scientifically valid peer-reviewed published toxicological data. Staff considered appropriate modifications in accordance with 15A NCAC 02L .0202(d) and (e)
and prepared reports which were reviewed by internal staff and then submitted to toxicology staff at both the Division of Waste Management and the Occupational and Environmental Epidemiology Branch within the NC Department Health and Human Services for secondary review. Staff then proposed amendments to 15A NCAC 02L .0202 in order to incorporate a number of these IMACs into groundwater quality standards.
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As part of the two-year process to develop the materials for the Groundwater and Waste
Management Committee (GWWMC) of the EMC, there was a series of presentations staff made
leading up to the rulemaking action item. An information item was presented to the GWWMC in July 2018 by DWR staff. This information item provided an overview of the groundwater quality standards, the IMAC review process that staff had completed, and a summary of the recommendations that DWR intended to make to the GWWMC as an action item. The GWWMC
was also informed that staff had begun working on the Regulatory Impact Analysis. Staff
returned to the GWWMC in September 2019 and January 2020 to request approval of the proposed amendments to the rule to proceed to the EMC. At the request of the GWWMC, staff returned in May and July of 2020 with additional information items which provided detailed descriptions of the proposed groundwater standards for each IMAC that was reviewed. On
September 9, 2020, an action item was presented to the GWWMC requesting approval of the
proposed amendments to the rule text to proceed to the EMC. This request was approved by the GWWMC. The EMC approved taking the proposed rule amendments and the Regulatory Impact Analysis
out to public comment and hearing at their November 19, 2020 meeting. Information presented
and other meeting materials are available on the EMC’s website and the November 2020 agenda (Agenda Item 20-31).
III. SUMMARY OF PROPOSALS
The proposed changes to the 15A NCAC 02L .0202 Groundwater Quality Standards that were
presented at the public hearing are summarized below:
• The adoption of a groundwater quality standard for 44 substances with established
IMACs, some with revisions,
• the addition of a groundwater quality standard for three substances (2,6-
dinitrotoluene, strontium, and total PFOA and PFOS) without established IMACs,
• the organization of the groundwater standards into a table,
• the addition of CASRNs for the groundwater standards,
• the removal of synonyms,
• a change in some units of measure to parts per billion or µg/L, when appropriate,
• the addition of rule text to 15A NCAC 02L .0202(c) to add a notification process for
the establishment of an IMAC, and
• the addition of rule text to 15A NCAC 02L .0202(g) to clarify the triennial review
process.
IV. REGULATORY IMPACT ANALYSIS
A Regulatory Impact Analysis was prepared as required by the Administrative Procedure Act
(NCGS 150B-21-4) and is included as Attachment B in this report. The RIA was approved by
the Office of State Budget and Management on August 30, 2019. It was included as an
attachment for the item presented at the EMC’s November 2020 meeting (Agenda Item 20-31,
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Attachment B) and can also be found on the OSBM website at:
https://files.nc.gov/ncosbm/documents/files/DEQ_2019-08-30b.pdf.
The current version of 15A NCAC 02L .0202 and the practical quantitation limit (PQL) for each
substance served as the regulatory baseline for comparison to understand what the costs and
benefits of the proposed rule changes would be to impacted and regulated parties. The PQL is a
technology-based value and not based on health effects data; as such, it was not compared to a
groundwater standard for purposes of determining human health impacts. The only proposed
changes to the regulatory baseline were the proposed adoption of groundwater standards for 47
compounds.
In preparation of the RIA, multiple regulatory programs that use the groundwater quality
standards were contacted. These include the NC DEQ Division of Waste Management
Brownfields, Underground Storage Tanks, Superfund, Solid Waste, and Hazardous Waste
programs and the NC Department of Transportation Asphalt Testing Program. The Non-
Discharge Branch and the Groundwater Protection (now Groundwater Resources) Section within
DWR were also contacted.
Due to the high degree of variability among sites, variability in driver contaminants for cleanup,
the degree of contamination, the scale and complexity of remediation required to meet
groundwater standards, the protracted length of time required to remediate groundwater, the age
of some sites, and the lack of data, quantifying all of the potential costs and benefits was not
possible for the RIA. Qualitative descriptions of expected costs and benefits were provided for
all programs and quantitative data was provided when available with assumptions made.
Summary of Costs and Benefits Associated with Proposed Rule Changes: The approved RIA
concludes that a net direct benefit to regulated entities and state government can be expected as
groundwater standards that are numerically higher than the regulatory baseline would be adopted
for a majority of the compounds. For those compounds with proposed groundwater standards
that are numerically the same or less than the regulatory baseline, no quantifiable impact can be
expected because the PQL would remain the regulatory value. A zero to net positive indirect
benefit for well water consumers and the environment can be expected.
V. PUBLIC HEARING PROCESS
The EMC approved the request to proceed to public hearing with the proposed revisions to 15A NCAC 02L .0202 and the RIA at their November 19, 2020 meeting (Agenda Item 20-31). EMC member Yvonne Bailey was appointed to serve as the Hearing Officer.

In the abundance of caution, and to address protective measures to help prevent the spread of COVID-19, the Division held an online public hearing regarding the proposed revisions and regulatory impact analysis on February 2, 2021 at 6:00 pm. The announcement of the hearing and a WebEx link, password, and call-in number were published in the January 15, 2021 edition of the North Carolina Register (https://files.nc.gov/ncoah/documents/files/Volume-35-Issue-14-
January-15-2021.pdf). The public hearing announcement is included in Attachment C.
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Additionally, the announcement of the public comment period and the public hearing and background information was made available on the following websites:
DEQ Upcoming events: https://deq.nc.gov/news/events
DEQ Public notices and hearings: https://deq.nc.gov/news/events/public-notices-hearings DEQ Proposed rules: https://deq.nc.gov/permits-regulations/rules-regulations/proposed-rules DEQ Press releases: https://deq.nc.gov/news/press-releases/2021/01/15/deq-hold-public-hearing-proposed-changes-state%E2%80%99s-groundwater-quality
DWR, Classifications and Standards, Rules Review Branch:
https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-standards/groundwater-standards
The notice in the North Carolina Public Register also included information on how to submit
comments. The sixty-day comment period for the proposed rule revisions began on January 15,
2021 and ended on March 16, 2021.
VI.SUMMARY OF ORAL AND WRITTEN COMMENTS
AND RESPONSES TO COMMENTS
The proposed rule changes were presented at the online public hearing on February 2, 2021. The
Hearing Officer’s remarks and DWR staff presentation is included in Attachment D and
Attachment E, respectively. 57 people registered to attend the public hearing, and 20 people
registered to speak. A list of those registered to attend the hearing and a list of those who elected
to speak are included in Attachment F and Attachment G, respectively. A recording of the
hearing is available on the Division’s website.
A total of 769 individual written comments were received prior to the close of the comment
period on March 16, 2021. These written comments were all received by email, with the
exception of one received in the mail. Attachment H includes all received written comments.
The following is a summary of all relevant oral comments that were presented at the public
hearing and a summary of all relevant written comments received, along with staff responses.
1.Total PFOA and PFOS Standard
The majority of comments received addressed the proposed groundwater standard for total
perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and the regulation of
per- and polyfluoroalkyl substances (PFAS) compounds as a whole. Several of the commentsreceived identified similar points of concern and can be grouped based on a few specific topics:Different Values, Regulate PFAS as a Class, Current PFOA IMAC, and Other PFAS Comments.A summary of relevant comments and staff responses are below.
Background Information:
Proposed total PFOA and PFOS Standard: 0.07 µg/L (70 ppt)
Current PFOA IMAC: 2,000 µg/L
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Current PFOS IMAC: none, regulated at the PQL per 15A
NCAC 02L .0202(c)
Comments received from:
Coastal Carolina Riverwatch, Crystal Coast Waterkeeper, Haw River Assembly, League
of Women Voters of North Carolina, League of Women Voters - Lower Cape Fear,
League of Women Voters - Wake County, NC Child, NC Coastal Federation, NC
Conservation Network, NC League of Conservation Voters, NC Sierra Club, Toxic Free
NC, White Oak-New Riverkeeper Alliance, Winyah Rivers Alliance (these 14
environmental advocacy groups submitted their comments jointly with representatives
from NC Conservation Network and Toxic Free NC serving as the main contacts;
hereafter in the report, this joint submittal will be referred to as “representatives from NC
Conservation Network, Toxic Free NC, and 12 additional environmental advocacy
groups”), 3M, Clean Cape Fear, Cape Fear River Watch, Advance Carolina, Center for
Environmental Health, Democracy Green, North Carolina Manufacturer’s Association,
Environment North Carolina, City of Southport Board of Alderman, National Resources
Defense Council (including 622 public comments from members), and about 757
template comments (representing private citizens)
Comment Topics:
Different Values:
A number of comments received requested a groundwater quality standard for total PFOA and PFOS at a different value than the proposed 70 ppt value. These comments are summarized and
grouped by the suggested revised value below:
1. Comment: A groundwater quality standard for a total concentration of all PFAS compounds
should be set at 1 ppt. (Clean Cape Fear, 221 comments including template comments from
citizens)
Response: In accordance with 15A NCAC 02L .0202(d), groundwater quality standards are
established as the least of the following: (1) the systemic threshold concentration; (2) the
concentration which corresponds to an incremental lifetime cancer risk of 1x10-6 ; (3) the
taste threshold limit value, (4) the odor threshold limit value; (5) the maximum contaminant
level; (6) or the national secondary drinking water standard. 15A NCAC 02L .0202(e) also
lists the references in order of preference that must be used to establish these values in order
of preference: (1) EPA’s Integrated Risk Information System (IRIS); (2) EPA’s Office of
Drinking Water Health Advisories; (3) other health risk assessment data published by EPA;
and (4) other relevant, published health risk assessment data, and scientifically valid peer-
reviewed published toxicological data. In the absence of an EPA IRIS assessment for PFOA
or PFOS, the proposed groundwater standard for total PFOA and PFOS is based on the
EPA’s Office of Drinking Water Health Advisories for PFOA and PFOS from 2016.
Staff acknowledges that more research is needed regarding immunotoxicity effects of PFAS
compounds, particularly using human data, as discussed in the Grandjean and Budtz-
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Jorgensen (2013) paper which was included in the comments from Clean Cape Fear. This
study was the first to present benchmark dose results for human PFAS exposures. The main
conclusion that the authors appeared to make in the context of this study was that EPA’s
limits for PFOA and PFOS in drinking water at the time were too high. EPA’s provisional
health advisories at that time were 0.4 μg/L or 400 ppt for PFOA and 0.2 μg/L or 200 ppt for
PFOS.
This study, however, only approximated exposure limits for drinking water for PFOA, as
there was no data available to correlate concentrations in drinking water with the serum
concentrations for PFOS or other PFAS. It would be inappropriate to establish a standard for
all PFAS at 1 ppt based on this study.
At this time, there is not enough evidence available that will allow the Division to propose a
groundwater standard for all PFAS compounds as a class. Please see below for a further
response.
2. Comment: A groundwater quality standard should be set at 10 ppt for any individual PFAS
compound and at 70 ppt for a total concentration of all PFAS compounds. (21 comments
from citizens, Jeannie Ambrose- resident of Chatham County, The City of Southport Board
of Aldermen)
and
Comment: The Commission should set a standard that reflects the values in the Chemours
Consent Order (10 ppt for individual compounds and 70 ppt for all PFAS compounds) so as
not to undermine that level of protection. (Representatives from NC Conservation Network,
Toxic Free NC, and 12 additional environmental advocacy groups)
Response: Division staff recognize that the Chemours Consent Order requires Chemours to
provide replacement water supplies for any party whose private drinking water well tested
above 10 ppt for individual PFAS compounds defined in the Consent Order and 70 ppt for
combined PFAS compounds defined in the Consent Order. These values were chosen based
on the PQL for GenX at the time and the EPA’s 2016 Drinking Water Health Advisories for
PFOA and PFOS, respectively. When calculating groundwater standards, the Division must
follow the procedures in 15A NCAC 02L .0202.
Establishing a health-based groundwater standard for total PFOA and PFOS will not remove
this protection for these parties as Chemours is held to the requirements in the agreed upon
Consent Order. A health-based value for PFOA and PFOS would only apply to certain
private wells surrounding the facility if Chemours “demonstrates to the reasonable
satisfaction of DEQ that the PFAS in a given well did not originate from the Facility”
(Attachment C of the Consent Order).
3. Comment: A groundwater quality standard should be set at 20 ppt for any individual PFAS
compound and for a total concentration of all PFAS compounds. (Environment North
Carolina, Representatives from Haw River Assembly, Catawba Riverkeeper Foundation,
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Yadkin Riverkeeper, Winyah Rivers Alliance, and 141 comments including template
comments from citizens)
and
Comment: Cape Fear River Watch recommended that EMC set a groundwater standard of
20 ppt or lower, combined for PFOA, PFOS, plus a set of 5 indicator PFAS chosen by the
Commission with support of NC Collaboratory researchers.
and
Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups stated that recent studies show flaws in the EPA
Health Advisories for PFOA and PFOS. They encouraged the Commission to adopt the
same RfD as that recommended by Wisconsin, which they state uses more accurate
pharmacokinetic modeling than that used by EPA. The state of Wisconsin is considering a
combined standard of 20 ppt for the sum of PFOA and PFOS.
and
Comment: North Carolina should follow the model developed by the Minnesota Department
of Health (Goeden et al., 2019) rather than the model used by the EPA when developing the
Drinking Water Health Advisories for PFOA and PFOS. (Representatives from Cape Fear
River Watch, Advance Carolina, Center for Environmental Health, Clean Cape Fear,
Coastal Carolina Riverwatch, Crystal Coast Waterkeeper, Democracy Green, Haw River
Assembly, White Oak-New River Assembly, and Winyah Rivers Alliance).
Response: The Division recognizes that the pharmacokinetic model used by the EPA has
limitations, including not accounting for potential infant exposures. However, at this time,
vertical transmissions models that incorporate infant exposures via placental transfer and
breastfeeding are lacking. The studies cited in the comments from these groups (Kieskamp
et al., 2018 and Goeden et al., 2019) do attempt to account for these exposure pathways.
However, these studies also have uncertainties and limitations and have not been
appropriately validated.
The Kieskamp et al. study was used by the Wisconsin Department of Health Services (DHS)
in the selection of a human equivalent dose that was then used to determine a groundwater
standard for PFOA of 20 ppt. This value was calculated using exposure parameters (body
weight, drinking water intake rate, and RSC) that differ from those defined in 15A NCAC
02L .0202(d)(1).
At this time, the Division supports the use of the validated Wambaugh et al. (2013)
pharmacokinetic model. EPA’s National Center for Environmental Assessment and National
Center for Computational Toxicology are in the process of preparing a toxicokinetic model
for pregnancy and gestation that is expected to be an improvement compared to currently
available pharmacokinetic models. A manuscript detailing this new model is expected soon
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as discussed by Kapraun et al., 2019 (available at this link). DEQ will continue to evaluate
newly published data and information, including this forthcoming maternal transfer model.
At this time, there is not enough evidence available that will allow the Division to propose a
groundwater standard for all PFAS compounds as a class. Please see below for a further
response.
4. Comment: General opposition to the proposed 70 ppt groundwater quality standard for
total PFOA and PFOS, with the request to set a lower unspecified value. (354 comments
including template comments from citizens)
Response: Staff appreciates these comments. DEQ continues to evaluate newly published
data and information regarding PFAS compounds so that any proposed regulatory value
provides appropriate protection for human health based on the data available at that time.
5. Comment: The Commission should set a groundwater standard of 0.1 ppt for PFOA and 0.4
ppt for PFOS as California’s Office of Environmental Health Hazard Assessment
recommended in 2019. (Natural Resources Defense Council, Representatives from NC
Conservation Network, Toxic Free NC, and 12 additional environmental advocacy groups)
Response: These values were recommended by California’s Office of Environmental Health
Hazard Assessment (OEHHA) by deriving a cancer slope factor calculated using animal
bioassay data reported in summary tables by the National Toxicology Program in 2018. Of
note, these recommended values by OEHHA were below the limit of quantitation of current
analytical methods. Therefore, the State Water Resources Control Board’s Division of
Drinking Water (DDW) set the Notification Levels at the lowest levels that can be reliably
detected using available technologies (5.1 ppt for PFOA and 6.5 ppt for PFOS). Notification
Levels in California are health-based advisory levels that are nonregulatory, precautionary
health-based measure for concentrations in drinking water that warrant notification and
further monitoring and assessment. These are not regulatory standards.
Staff agrees that any potential carcinogenetic effects are concerning. In their 2016 Drinking
Water Health Advisory, EPA did evaluate PFOA for cancer risk and found that the lifetime
Health Advisory derived from noncancer endpoints was also protective of cancer endpoints.
EPA found the data too limited to support a quantitative assessment for cancer risk for
PFOS at that time. The Division will continue to monitor the data regarding cancer risk for
these compounds.
6. Comment: PFOS should be regulated at the PQL.
and
Comment: All PFAS compounds should be regulated at the PQL or the reporting limit.
Response: The PQL is a laboratory value that can change with updated analytical
capabilities and may vary across different laboratories. This provides uncertainty and
potential variations in regulatory actions. When there is enough data available to establish a
health-based standard, it is not appropriate to regulate compounds at the PQL.
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The Secretaries’ Science Advisory Board heard about this issue at their December 2019
meeting and provided a written statement in response (provided as an attachment at the
November 2020 EMC meeting- Agenda Item 20-31, Attachment D, and included as
Attachment A in this report). The SSAB included in their statement their recommendation
that a health-based value for PFOA and PFOS should be established rather than the PQL.
They do state that data for other PFAS compounds is lacking, therefore regulating them at
the PQL is an appropriate approach.
7. Comment: Other states and agencies have developed or established different values for
PFAS guidelines, advisories, and regulations.
Response: It is worth noting that every state develops and uses health-based values in
varying ways within different programs. Groundwater quality standards in North Carolina
must be developed using the procedures stated in 15A NCAC 02L .0202. In addition to
different procedures for calculating health-based values, states and agencies also have
differing interpretations of the data surrounding PFAS.
States and agencies in the U.S. and other countries have recommended and established
standards, guidance, and screening values for PFOA and PFOS in groundwater, drinking
water, and surface water in the range of 0.0051 µg/L to 0.667 µg/L or 5.1 ppt to 667 ppt
(Interstate Technology and Regulatory Council PFAS Water and Soil Values Table Fact
Sheet). For total PFOA and PFOS, Alaska, Colorado, Delaware, Maine, New Mexico, and
Ohio base their regulations on the EPA 2016 Drinking Water Health Advisories for PFOA
and PFOS. States such as Minnesota, Michigan, New Hampshire, and Vermont have
calculated different values for PFOA and PFOS with procedures that do not follow the
procedures required in 15A NCAC 02L .0202. Staff continues to monitor for newly
published data and information regarding PFAS compounds.
Regulate PFAS as a Class:
1. Comment: PFAS should be regulated as a class or a subclass. (Environment North
Carolina, Natural Resources Defense Council, Haw River Assembly, Catawba Riverkeeper
Foundation, Yadkin Riverkeeper, Winyah Rivers Alliance, Jeannie Ambrose- resident of
Chatham County, Cape Fear River Watch, Advance Carolina, Center for Environmental
Health, Clean Cape Fear, Coastal Carolina Riverwatch, Crystal Coast Waterkeeper,
Democracy Green, White Oak-New River Assembly, template comments from citizens)
and
Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups urged the Commission to consider that PFAS
rarely travel alone. They stated that a standard that is set for PFOS and PFOA alone and
does not assume concurrent exposures to other PFAS is unlikely to address the actual risk
to water users posed by PFAS contamination in groundwater.
and
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Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups recommended that the Commission should
establish a class or subclass standard for PFAS based on studies of a handful of class
members and enforce it as the sum of PFAS measured under EPA Method 537.1. They
further suggested that the Commission should allow a party the ability to bring evidence
that a specific PFAS has lower toxicity than the class standard to the Commission or
Director and ask for a separate standard (or IMAC) for that compound. Natural Resources
Defense Council made a similar comment, while recommending the use of the 537-modified
(537-M) method and a subclass including at least the compounds PFOA, PFOS, PFNA,
PFHxS, GenX, PFBS, PFBA, PFPeA, PFHxA, PFDA, PFUnA, PFDoA, PFTA, PFTrDA,
PFDS, and PFOSA.
Response: As stated above, at this time, there is not enough evidence available that will
allow the Division to propose a groundwater standard for all PFAS compounds as a class in
accordance with 15A NCAC 02L .0202. These compounds vary in physiochemical,
environmental, and toxicological properties which makes grouping them difficult and
complex. The rule language in 15A NCAC 02L .0202 does not allow for staff to calculate
groundwater standards for a group of compounds which vary in toxicological endpoints and
values. While there have been arguments posed for regulating these chemicals as a class
(Kwiatkowski et al., 2020, Massachusetts DEP), a definitive system for grouping has not
been decided upon by the scientific community.
The Division acknowledges that regulating PFAS compounds on an individual basis may
not be technologically or fiscally feasible in the long run. However, in order to calculate a
health-based groundwater standard in accordance with 15A NCAC 02L .0202(d), either a
reference dose or a cancer slope factor is needed. Toxicological data available for a number
of known PFAS compounds are lacking, which means the Division is unable to calculate a
health-based groundwater standard for the majority of these compounds.
In the absence of toxicological or health-based information for individual PFAS compounds,
these compounds are not permitted in concentrations above the PQL in groundwater. The
PQL value is the lowest concentration of a given material that can be reliably achieved
among laboratories within specified limits of precision and accuracy by a given analytical
method during routine laboratory analysis. The PQL values for certain compounds are often
more stringent than calculated health-based values. At this time, because the Division is
unable to propose a class based PFAS groundwater quality standard, the majority of PFAS
compounds will not be allowed in groundwater in concentrations above their PQL value.
2. Comment: Regulation of PFAS should follow the Toxic Equivalency Factor (TEF) model
used in PCDD, PCDFs, and PCBs. (George Pauly- resident of Chatham County) Response: Thank you for your comments. The Toxic Equivalency Factor method is a useful
approach in risk assessment for mixtures or groups of related chemicals that produce similar
hazardous effects through the same mechanism. TEF is currently used in risk assessments for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs),
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and polychlorinated biphenyls (PCBs) as these compounds are chemically and toxicologically related and their mechanisms of actions are known. For PFAS compounds,
however, there is limited information on the mechanisms of toxicities for the majority of the
diverse individual compounds and it is unknown if these compounds have the same or similar critical effect. At this time, the Division does not believe that the TEF method is an appropriate approach to assessing or regulating PFAS compounds as a group.
3. Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups stated that the Commission should add a new
subsection providing for adoption of appropriate class-based groundwater standards.

and
Comment: Representatives from Cape Fear River Watch, Advance Carolina, Center for
Environmental Health, Clean Cape Fear, Coastal Carolina Riverwatch, Crystal Coast
Waterkeeper, Democracy Green, Haw River Assembly, White Oak-New River Assembly, and
Winyah Rivers Alliance stated that the Commission should consider a change in rule
language to accommodate a class approach to groundwater standards.
Response: Please see section “2. Additional Comments: Proposed Additions and Changes”
below for response to these comments.
Current PFOA IMAC:
1. Comment: The current PFOA IMAC of 2,000 ppt needs to be repealed (Clean Cape Fear,
and Representatives from NC Conservation Network, Toxic Free NC, and 12 additional environmental advocacy groups).
and

Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12 additional environmental advocacy groups further commented that they recognize that the Commission may decide it wants or needs to explore policy implications in greater depth before setting a standard. If the Commission decides that further study of PFAS compounds
would be advisable, they urged that at a minimum, the 2006 IMAC for PFOA is repealed
now. Response: North Carolina was one of first states to set a regulatory value for PFOA when
the IMAC was established in 2006. The Division acknowledges that the current IMAC
value of 2,000 ppt for PFOA is outdated and needs to be updated in accordance with the scientific literature that has been published since that time. The Division recognizes that it is a priority to either rescind this IMAC or to update this value.
16 | Page

Other PFAS Comments:
1. Comment: 3M encouraged DEQ to clarify how the EPA’s Drinking Water Lifetime Health
Advisory was chosen over the criteria in 15A NCAC 02L .0202(d) for the proposed total
PFOA and PFOS standard.
Response: In accordance with 15A NCAC 02L .0202(e)(2), and in the absence of an EPA
IRIS assessment for PFOA or PFOS, the 2016 EPA Drinking Water Health Advisories
were chosen as the reference used to establish a proposed groundwater quality standard for
total PFOA and PFOS. The 2016 EPA Drinking Water Health Advisories for PFOA and
PFOS are calculated using the same formula as the systemic threshold concentration
defined in 15A NCAC 02L .0202(d)(1), with the exception of the exposure factors. The
exposure factors used by the EPA to calculate the PFOA and PFOS Health Advisories are
specific to lactating women as they are considered to be the most sensitive population and
therefore the protection offered by the lifetime Health Advisory would be broadly
protective of public health. EPA considers lactating women to be the most sensitive
population due to the potential increased susceptibility during the time period of pregnancy
and lactation and due to the increased water intake rate of lactating women in relation to
body weight. In order to protect the sensitive subpopulation, the Division based the
proposed PFOA and PFOS groundwater quality standard on the lifetime Health Advisories
calculated by EPA. DEQ continues to evaluate newly published data and information
regarding PFAS compounds.
2. Comment: 3M stated that the EPA’s health advisory levels for PFOA and PFOS do not
reflect the determination in the latest EPA Exposure Factors Handbook (2019) that the
current 90th percentile consumers-only estimated community water ingestion for lactating
women is 0.047 L/kg (direct and indirect combined).
Response: EPA individually released the update for the Chapter 3 Ingestion of Water and
Other Select Liquids of the Exposure Factor’s Handbook in 2019 during the rulemaking process for this proposed rulemaking package. The average adult Recommended Values for Drinking Water Ingestion Rates and the
Recommended Values for Water Ingestion Rates of Community Water for Pregnant and
Lactating Women were both updated. The value for the combined direct and indirect community water ingestion for lactating women changed from the 90th percentile consumers only estimate of 0.054 L/kg-day to the 95th percentile consumers only estimate of 0.047 L/kg-day. Due to the timing of this chapter release, staff will consider the updated
Exposure Factor’s Handbook Ingestion Rate values during the next triennial review and
update all Groundwater Quality Standards as appropriate.
3. Comment: 3M provided technical comments on pages 142-145 of the Groundwater Quality Standards Supporting Documents included as an attachment at the November 19, 2020
EMC meeting (Agenda Item 20-31, Attachment C).

17 | Page

Response: Staff thanks 3M for their detailed technical comments. The PFOA and PFOS Supporting Documents have been updated to include this information as appropriate, as
shown in Attachment I of this report.
4. Comment: Clean Cape Fear requested that PFAS measured via EPA method 537.1 should
be included in the Division of Waste Management’s Inactive Hazardous Site program’s
Guidelines for Assessment and Cleanup of Contaminated Sites protocol.
Response: Staff appreciates this suggestion and has passed them on the to the Division of
Waste Management’s Inactive Hazardous Site Branch.
5. Comment: Clean Cape Fear requested that the state set the lowest possible standard for
PFOA and PFOS, rather than regulate them at the PQL.

Response: Staff understands the request to establish groundwater standards based on health
endpoints rather than rely on the PQL. When there is enough data available to establish a
health-based standard, it is not appropriate to regulate compounds at the PQL. There is
enough toxicological information available for PFOA and PFOS that allows the Division to
propose a health-based groundwater standard for these compounds in accordance with 15A
NCAC 02L .0202.

The Secretaries’ Science Advisory Board heard about this issue at their December 2019
meeting and provided a written statement in response (included as Attachment A in this
report). The SSAB included in their statement their recommendation that a health-based
value for PFOA and PFOS should be established rather than the PQL. They do state that
data for other PFAS compounds is lacking, therefore regulating them at the PQL is an
appropriate approach.

6. Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups request that if the Commission chooses to set a
standard for PFOS and PFOA alone, that it issues clear policy guidance that groundwater
sampling must test for a suite of PFAS, not just PFOS and PFOA.

Response: Staff thanks these groups for their comment and has shared this request with
relevant groups within the Division of Waste Management, including the Solid Waste and
Hazardous Waste programs.
The Division of Water Resources’ Groundwater Management Branch within the
Groundwater Resources Section collects monitoring groundwater well data throughout the
state. Currently, a suite of PFAS compounds is tested in groundwater wells that are
sampled within the DWR Monitoring Well Network. More information about the
Monitoring Well Network and the current sampling efforts can be found on the Branch’s
Groundwater Quality website and results obtained to date can be viewed at this link.
18 | Page

7. Comment: Representatives from Haw River Assembly, Catawba Riverkeeper Foundation,
Yakin Riverkeeper, and Winyah Rivers Alliance stated that setting a groundwater standard
to address only the legacy PFOA and PFOS compounds does not address the contaminants
still in production processes that fill construction and demolition landfills and municipal
landfills.
Response: Landfill operations in the state of North Carolina must comply with groundwater
quality standards or IMAC levels established under 15A NCAC 02L (see 15A NCAC
Subchapter 13B). In accordance with 15A NCAC 02L .0202(c), in the absence of a
standard or IMAC, substances shall not be permitted in groundwater in concentrations at or
above the PQL. The majority of PFAS compounds are not allowed in groundwater at
concentrations above their PQL value and this will continue if a groundwater standard for
PFOA and PFOS is established.
8. Comment: North Carolina needs to establish fish consumption advisories due to PFAS
contamination. (Representatives from Cape Fear River Watch, Advance Carolina, Center
for Environmental Health, Clean Cape Fear, Coastal Carolina Riverwatch, Crystal Coast
Waterkeeper, Democracy Green, Haw River Assembly, White Oak-New River Assembly,
and Winyah Rivers Alliance).

Response: This comment has been shared with the NC Division of Public Health within the
Department of Health and Human Services as this group issues fish consumption advisories
in North Carolina.

9. Comment: The Commission’s actions to designate groundwater standards or surface water
standards are necessary to control pollution already in drinking water supplies, but they
should not preclude DEQ from adhering to federal law and requiring industrial
dischargers reduce PFAS effluent to the level attainable by current and readily available
technology, the level of which has been shown to be, for most PFAS, lower than the
detection limit. (Representatives from Cape Fear River Watch, Advance Carolina, Center
for Environmental Health, Clean Cape Fear, Coastal Carolina Riverwatch, Crystal Coast
Waterkeeper, Democracy Green, Haw River Assembly, White Oak-New River Assembly,
and Winyah Rivers Alliance).

Response: Staff thanks these groups for their comments. This comment has been shared
with programs within the Division that are responsible for NPDES permitting.
2. Additional Comments
Support of Proposed Changes:
1. Comment: Support use of Chemical Abstract Service Registry Numbers to reduce ambiguity.
(Representative from Clean Water for North Carolina)

Response: Thank you for the comment.
19 | Page

2. Comment: Support the Division’s proposal for a combined standard for two types of PFAS.
(Natural Resources Defense Council).

Response: Thank you for the comment.

3. Comment: Support adoption of proposed groundwater standards, with the exception of
PFOA and PFOS. (Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups)

Response: Thank you for the comment.

4. Comment: Support decision to prioritize IMACs in this review since those have not
previously received a public review. (Representatives from NC Conservation Network, Toxic
Free NC, and 12 additional environmental advocacy groups)

Response: Thank you for the comment.

5. Comment: Support proposed changes to the 02L .0202(c) rule language to strengthen
process by which the Division issues IMACs as they believe that the proposed requirement
for public notice will increase transparency. Support proposed rule language that requires
IMACs be developed the same as groundwater standards. (The City of Southport Board of
Aldermen, Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups)

Response: Thank you for the comment.

6. Comment: Support proposed changes to the 02L .0202(g) rule language that an IMAC will
be reviewed in a public process at the next triennial review. (The City of Southport Board of
Aldermen, Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups)

Response: Thank you for the comment.

Proposed Additions and Changes:
1. Comment: The requirement that interim standards and all relevant data are reviewed and
adjusted as data suggests, every three years needs to be strengthened. If more consistent
funding and staffing is necessary to meet the obligations under .0202(g), recommend that this
is called for by the hearing officers. (Representatives from Cape Fear River Watch, Advance
Carolina, Center for Environmental Health, Clean Cape Fear, Coastal Carolina Riverwatch,
Crystal Coast Waterkeeper, Democracy Green, Haw River Assembly, White Oak-New River
Assembly, and Winyah Rivers Alliance).
20 | Page

Response: Division staff thanks these groups for their comments. Staff believes that the
proposed revisions to 15A NCAC 02L .0202(g) do strengthen the IMAC review process and
provide more guidance and transparency regarding how IMACs are reviewed.

2. Comment: North Carolina Manufacturer’s Association commented that the proposed
amendments are an improvement as they address the need for public review of a proposed
IMAC prior to its adoption, but further language should be added that requires the Director
to consider the public comments received during the public notice period prior to
establishing an IMAC.
Response: Staff appreciates this comment and request. The proposed rule language does add
a public involvement process by requiring the Division to publish a notice in the North
Carolina Register at least 30 days prior to the establishment of an IMAC. Information
published in the public notice must include the request for the establishment of the IMAC,
the level of the proposed IMAC, and the basis upon which the Division relied upon in
development of the proposed IMAC. A mailing address and email address will also be
provided in the public notice for further questions and if any member of the public wishes to
provide comments on the intended action. At the end of the 30-day period, any comments
received will be provided to the Director.
3. Comment: North Carolina Manufacturer’s Association commented that under the proposed
rule, there is no time frame within which a decision on an IMAC petition must be rendered.
The EMC should resolve this issue and ensure timely action on such petitions by adding a
sentence at the end of 02L .0202(c) that reads: “The Director shall issue or deny a petition
for an IMAC within 180 days of receipt of the petition.”
Response: The requests that the Division receives to establish IMACs for substances are
unique and vary greatly on factors such as the strength and availability of data. Some
requests are complicated and take time to gather and examine appropriate toxicological data.
Often further communication is needed with the requestor and/or with the EPA. Also, an
external review is conducted with both the Division of Waste Management and the
Occupational and Environmental Epidemiology Branch of the Department of Health and
Human Services.
While it is understood that the requestor wants timely action, requiring a deadline to either
issue or deny an IMAC would limit the Division’s ability to work with the requester and
other agencies during the IMAC establishment process. If the deadline passes and the
necessary discussions and review are not completed or the appropriate data and information
have not been received or located, the IMAC request must be returned and resubmitted. This
may cause further work for both the Division and the requestor. If the requestor wishes to
establish a health-based standard for a compound in groundwater outside of the IMAC
process, there is still a formal petition process available to them.
21 | Page

4. Comment: North Carolina Manufacturer’s Association commented that although the
proposed rule does require notice by the Director to the EMC that an IMAC has been
established, there is no provision that compels either the Director or the Commission to
initiate rulemaking to formally adopt an IMAC in a manner consistent with the current
requirements of the Administrative Procedures Act found in NCGS 150B.
Response: The Division believes that the proposed rule language provides more transparency
regarding the IMAC establishment and review procedures. The proposed rule language
continues to require a review of all IMACs and groundwater quality standards on a triennial
basis and adds language that defines the options that the Director shall take during the review
of an IMAC. This includes codifying the IMAC as a groundwater quality standard, which
would initiate the formal rulemaking process.
It is understood that regulated entities and the public may want an established IMAC to be
subject to the formal rulemaking requirements set out in the APA including public
involvement provisions. The formal rulemaking process is available for this.
5. Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups recommended that the EMC broaden the
language in .0202(c) to allow third parties to request that the Director revisit an existing
IMAC on the basis of new scientific information of the types described in .0202(d) and (e).
They stated the concern that under the existing and proposed rule language, a petitioner can
propose an IMAC, but a citizen cannot ask the Director to revisit it as the only option
available to them is to file a full rulemaking petition with the EMC.
Response: Staff thanks these groups for their comments. Staff recommends revising the
language in 15A NCAC 02L .0202(c) to address this concern as shown below in highlighted
text and in Attachment J of this report:
(c) Except for tracers used in concentrations which have been determined by the
Division of Public Health to be protective of human health, and the use of which has been
permitted by the Division, substances which are not naturally occurring and for which no
standard is specified shall not be permitted in concentrations at or above the practical
quantitation limit in Class GA or Class GSA groundwaters. Any person may
petitionrequest the Director of the Division of Water Resources to establishestablish,
update, or remove an interim maximum allowable concentration Interim Maximum
Allowable Concentration (IMAC) for a substance for which a standard has not been
established under this Rule. In response to the request, the Director of the Division of
Water Resources may establish, update, or remove an IMAC. The petitionerrequester
shall submit relevant toxicological and epidemiological data, study results, and
calculations necessary to establish a standard in accordance with ParagraphParagraphs (d)
and (e) of this Rule. Within three months after the establishment of an interim maximum
allowable concentration for a substance by the Director, the Director shall initiate action
to consider adoption of a standard for that substance.If the information submitted is not in
accordance with Paragraphs (d) and (e) of this Rule, the Director of the Division of Water
22 | Page

Resources shall request additional information from the petitionerrequester. If the
petitionerrequester does not provide the additional information necessary to be in
accordance with Paragraphs (d) and (e) of this Rule, the Director of the Division of Water
Resources shall denyreturn the petitionrequest. At least 30 days prior to establishing,
updating, or removing an IMAC for any substance, the Division of Water Resources shall
provide public notice that an IMAC has been requested to be established, updated, or
removed. The public notice shall include the petitionrequest requestingfor the
establishment, update, or removal of the IMAC for a substance, the level of the proposed
IMAC, if applicable the level of the existing IMAC, and the basis upon which the
Division of Water Resources has relied in development of the proposed IMAC
establishment, update, or removal. This notice shall be published in the North Carolina
Register and posted on the Division of Water Resources’s website:
https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-
standards/groundwater-imacs. If the Director of the Division of Water Resources
establishes or updates an IMAC, the IMAC shall be posted on the Division of Water
Resources’s website, and the Commission shall be notified in writing within 30 calendar
days that a new IMAC has been established or an existing IMAC has been updated or
removed.

6. Comment: Natural Resources Defense Council stated that the default values for relative
source contribution and drinking water ingestion rate are not protective of the most
vulnerable populations, particularly to PFAS exposures.

and

Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups stated that the Commission should add new
language to .0202 allowing for consideration of salient factors in risk assessment that the
existing rule language does not acknowledge. The following revision to 02L .0202(d) was
proposed:
(d) Except as provided in Paragraph (f) of this Rule, groundwater quality standards for
substances in Class GA and5 Class GSA groundwaters are established as the least of:
(1) Systemic threshold concentration calculated as follows: [Reference Dose
(mg/kg/day) x 70 kg (adult body weight) x Relative Source Contribution (0.10 for
inorganics; 0.20 for organics)] / [2 liters/day (avg. water consumption)];, derived
from an appropriate toxicokinetic model, or by a risk assessment formula with
Reference Dose, Body Weight, and Relative Source Contribution that reflect the
most vulnerable population exposed to the substance;
The following subsection was also proposed:
(d1) In calculating the factors under (d), the Commission, or in the case of an IMAC the
Director, may account for historic or baseline exposures and may apply a peer-reviewed
23 | Page

model that accounts for groundwater exposure pathways as a component of total life
exposure to a substance.
Response: Staff appreciates this suggestion and request. Defining the procedure to calculate
the systemic threshold concentration in rule can be beneficial as it provides consistency in
establishing groundwater quality standards. However, staff acknowledges that risk
assessment may not always have a “one size fits all” solution for every substance. This
subject will likely attract interest from the broader public who would like to comment on
potential changes to the rule language.
The Division will consider this suggestion during the next triennial review and consider
getting specific public comments on this subject in the next rulemaking.
7. Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups stated that the Commission should add a new
subsection providing for adoption of appropriate class-based groundwater standards. The
following subsection was proposed:
(d2) Where substances in a class or subclass share exposure pathways, structural
similarities, or suspected health effects or mechanisms of harm, the Commission, or in
the case of an IMAC, the Director, may set standard for the class or subclass based on
data in (d) pertaining to one or more substances in the class. Any person who believes a
substance in a class exhibits substantially different toxicological characteristics and
should not be regulated as a member of that class may petition the Director under (c) to
establish an IMAC for that substance. If the IMAC or a separate standard is established
for that substance, it shall not also be regulated as a member of the class.
and
Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups suggested options to approach a class-based
standard, including (1) setting a standard based on a member of the class and measuring
compliance as the cumulative concentration of class members; (2) setting a standard based
on multiple class members, measured as the cumulative concentration of class members
known to be toxic; and (3) setting a standard based on one member of the class, and
demonstrating compliance through direct measurement of the total concentration of the
class.
Response: Staff appreciates these comments. Use of the “class” and “subclass” terms in the
proposed language may be problematic if included in the rule language for groundwater
standards. Substances could be classified based on their physical properties, structural
similarities, uses, or various other factors. Defining classes and subclasses for particular
substances may not be possible or may vary considerably based on differing scientific
interpretations. Including the language “exposure pathways, structural similarities, or
suspected health effects or mechanisms of harm” does not exclusively define a class or
24 | Page

subclass of substances. Without clarifying how to specifically define a class or subclass of
substances, this rule language could be considered ambiguous.
Staff thanks these groups for their thorough and detailed comments and suggestions on
potential approaches to regulate substances as a class. Staff believes that this subject will
attract public interest by parties who would like to comment on any proposed change in rule
language regarding allowing regulations of chemicals by class. The Division will consider
these suggestions during the next triennial review and will consider soliciting comments on
this particular subject at that time.
Regulatory Impact Analysis:
1. Comment: 3M stated that while DEQ admittedly faced several challenges to quantifying the
costs and benefits of the Proposed Regulations, the inability of DEQ to quantify costs and
benefits is a result of the lack of pre-regulatory sampling. For example, without data on
current levels of PFOA and PFOS at non-discharge sites, or an estimate of how many sites
would exceed the practical quantitation limit, DEQ was unable to monetize the potential
economic impact to non-discharge permittees.
Response: Staff agrees that additional data, particularly for PFOA and PFOS, would have
enabled us to perform a more in-depth analysis. However, staff believes the depth of analysis
was appropriate given the available data, and that it was proportional to the nature and complexity of the rule changes, especially when considering the true regulatory impact as
compared to the existing IMACs.
2. Comment: 3M stated that DEQ focused on the practical quantitation limit as the baseline
standard for PFOA and other substances, even though the interim maximum allowable
concentrations serve as the regulatory requirement for those substances in practice.
Response: The North Carolina OSBM policy did not allow the IMACs to be used as the
regulatory baseline for purposes of the RIA as the IMACs were considered a temporary
requirement that had not been subject to the permanent rulemaking process. Staff did include
in the RIA some qualitative information on the impacts as compared to the IMACs to address
what the Division recognized as the true regulatory impact. Staff have subsequently initiated
more robust data and information gathering processes for requested IMACs that will better
enable the Division to quantify impacts in future rulemakings.
3. Comment: 3M stated that DEQ prepared a single RIA for the 47 contaminants for which
groundwater standards have been proposed and DEQ did not explicitly evaluate the costs
and benefits of the level of each proposed groundwater standard. This could, for example,
disguise if the costs of a particular standard outweigh the benefits of that standard.
Response: NC OSBM requires that impacts be considered on a rule-by-rule basis; as such, it
was necessary to present the impacts together in one RIA. Information for some
contaminants were combined and impacts generalized, when appropriate, to streamline the
document without losing any significant detail. Each contaminant was evaluated on its own,
however, within the context of each regulatory program. Further discussion was included for
25 | Page

those few contaminants that were identified as driver contaminants. If a contaminant is not
considered a driver contaminant, it is very unlikely that its adoption would result in
additional costs or benefits that would warrant an extensive separate analysis.
4. Comment: 3M stated that DEQ has proposed a combined standard for PFOA and PFOS but
did not fully assess how the combined nature of the standard would affect the related costs
and benefits of regulating each substance, despite the fact that there is an IMAC already in
place for PFOA and not for PFOS and the PFOA cleanup goal is changing by a larger order
of magnitude than the PFOS cleanup goal.
Response: Staff acknowledges that a more robust analysis of the combined PFOA and PFOS
standard relative to the regulatory baseline would be informative. However, there was not yet
a pool of data with which to perform a meaningful quantitative analysis, and many
uncertainties remained as to its ubiquity in different industries; as such, we were limited to a
qualitative discussion of potential impacts.
Other Comments:
1. Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups encouraged the Division to review existing
standards in .0202(h) and .202(i) as part of the next triennial review. They also urged the
Commission to not put off protective decisions to future review cycles.
Response: Division staff thanks these groups for their comments.
2. Comment: Representatives from NC Conservation Network, Toxic Free NC, and 12
additional environmental advocacy groups recommended and encouraged the Department to
digitize the state’s data on groundwater contamination and organize it in a database that
allows searches by chemical in order to provide information to members of the public on the
spatial distribution of specific contaminants. They also encouraged that this information be
placed into data layers and added to the Department’s community mapping tool, to support
searches for contamination not just by regulatory program, but also by the contaminants
known to be present at sites. They suggested that this will help the Commission and staff
prioritize attention in future cycles to the most widespread contaminants or those posing the
greatest practical risk to public health.
Response: Division staff appreciate these suggestions and agree that spatial information
regarding the use of groundwater standards would be useful for staff, the Commission, and
the public. These comments have been shared with relevant groups within DEQ, including
DWR and the Division of Waste Management.
3. Comment: Since groundwater and surface water are physically interconnected resources,
groundwater standards should be considered applicable to surface water standards as well.
(Jeannie Ambrose, resident of Chatham County).

Response: Staff recognizes that groundwater and surface water interactions are an area of
study that needs more research, especially in regard to risk assessments and the development
26 | Page

of water quality standards. North Carolina surface waters are protected by the federal Clean
Water Act and have their own standards developed under 15A NCAC 02B. Staff in DWR’s
Classifications, Standards and Rules Review Branch do communicate amongst themselves
when groundwater standards and surface water standards are developed and reviewed. This
communication is to coordinate for particular substances in terms of which data and
resources are reviewed and how calculations are performed.

4. Comment: A representative from the Ethylene Glycols Panel of the American Chemistry
Council requested documentation for the 15A NCAC 02L .0202 Groundwater Quality
Standard for ethylene glycol.
Response: Staff reached out to the commentor with information and available documentation
regarding the ethylene glycol groundwater standard. This groundwater standard was not
addressed during this rulemaking period as the current review focused on existing IMACs.
The commentor followed up with acknowledgment about the anticipated timeline for the
review for the ethylene glycol groundwater standard. The commentor also provided
additional written comments addressing the ethylene glycol groundwater standard which will
be examined and considered during the next triennial review.
5. Comment: A representative from Clean Haw River commented that 1,4-dioxane is at a high
level and needs to be kept at the lowest level possible.
Response: The Division continues to sample and monitor for 1,4-dioxane within the Cape
Fear River Basin in order to determine and assess potential sources of this compound and to
gather data to develop a regulatory strategy. More information is available on the Division’s
Cape Fear River Basin 1,4-Dioxane Study website. Additional information, including
information on in-stream target values for 1,4-dioxane in surface waters, is also available on
DEQ’s Managing Emerging Compounds in Water website. The existing groundwater
standard for 1,4-dioxane was not addressed during this rulemaking period as the current
triennial review focused on existing IMACs.
VII. RECOMMENDATIONS
The Division and the Environmental Management Commission-appointed Hearing Officer,
Yvonne Bailey, recommend that the proposed and public-noticed revisions to 15A NCAC 02L
.0202 be approved by the EMC, except as follows:
1. the proposed total PFOA and PFOS groundwater standard not be adopted, as shown in
the attached recommended rule text (Attachment J), and
2. with modifications to 15A NCAC 02L .0202 (c) and (g) as noted below and shown in
the attached recommended rule text (Attachment J).
In taking this action, the following rules will show that the Environmental Management
Commission has made revisions since these rules were public noticed as noted by the highlighted
text below:
27 | Page

(c) Except for tracers used in concentrations which have been determined by the
Division of Public Health to be protective of human health, and the use of which has been
permitted by the Division, substances which are not naturally occurring and for which no
standard is specified shall not be permitted in concentrations at or above the practical
quantitation limit in Class GA or Class GSA groundwaters. Any person may
petitionrequest the Director of the Division of Water Resources to establishestablish,
update, or remove an interim maximum allowable concentration Interim Maximum
Allowable Concentration (IMAC) for a substance for which a standard has not been
established under this Rule. In response to the request, the Director of the Division of
Water Resources may establish, update, or remove an IMAC. The petitionerrequester
shall submit relevant toxicological and epidemiological data, study results, and
calculations necessary to establish a standard in accordance with ParagraphParagraphs (d)
and (e) of this Rule. Within three months after the establishment of an interim maximum
allowable concentration for a substance by the Director, the Director shall initiate action
to consider adoption of a standard for that substance.If the information submitted is not in
accordance with Paragraphs (d) and (e) of this Rule, the Director of the Division of Water
Resources shall request additional information from the petitionerrequester. If the
petitionerrequester does not provide the additional information necessary to be in
accordance with Paragraphs (d) and (e) of this Rule, the Director of the Division of Water
Resources shall denyreturn the petitionrequest. At least 30 days prior to establishing,
updating, or removing an IMAC for any substance, the Division of Water Resources shall
provide public notice that an IMAC has been requested to be established, updated, or
removed. The public notice shall include the petitionrequest requestingfor the
establishment, update, or removal of the IMAC for a substance, the level of the proposed
IMAC, if applicable the level of the existing IMAC, and the basis upon which the
Division of Water Resources has relied in development of the proposed IMAC
establishment, update, or removal. This notice shall be published in the North Carolina
Register and posted on the Division of Water Resources’s website:
https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-
standards/groundwater-imacs. If the Director of the Division of Water Resources
establishes or updates an IMAC, the IMAC shall be posted on the Division of Water
Resources’s website and the Commission shall be notified in writing within 30 calendar
days that a new IMAC has been established or an existing IMAC has been updated or
removed.

(g) Groundwater quality standards specified in Paragraphs (h) and (i) of this Rule and
interim maximum allowable concentrationsIMACs established pursuant to Paragraph (c)
of this Rule shall be reviewed by the DirectorDivision of Water Resources on a triennial
basis.basis and reported to the Commission. The Director of the Division of Water
Resources shall considertake any of the following actions during the review of an
established IMAC:

28 | Page

Based on the comments received as well as the Division’s ability to consider new information to
establish and revise IMACs, the Hearing Officer recommends that the Commission not adopt the
proposed groundwater quality standard for total PFOA and PFOS that went out to notice. The
science on PFAS chemicals is developing and many studies are ongoing. The Division continues
to evaluate newly published data and expected forthcoming information on these compounds that
may change the proposed health-based values that went out to notice. This information includes
the improved pharmacokinetic model that EPA is developing, as discussed in the Kapraun et al.,
2019 study, and further scientific review by EPA leading to the establishment of Maximum
Contaminant Levels for PFOA and PFOS. The Division will consider this additional information
to pursue establishing IMAC values for PFOA and PFOS.

Secretaries’ Science Advisory Board
Summary statement on use of EPA's 2016 Drinking Water Health Advisory
values for PFOA and PFOS as a Groundwater Quality Standard
Note: At the Dec 2, 2019 meeting, the Secretaries' Science Advisory Board (SSAB)
provided a lot of feedback on the charge to "review and comment on the Division of
Water Resources’ recommendation to use the 2016 EPA Drinking Water Health
Advisory values for PFOA and PFOS as a Groundwater Quality Standard." The
SSAB was asked at the meeting for a more formal summary statement; the
members crafted it orally, and a draft was subsequently circulated for review. This is
the summary statement from that review.
The SSAB reviewed the information provided by the DEQ regarding the
development of a draft rule for establishing a groundwater standard for PFOA and
PFOS as referred for consideration by the Environmental Management
Commission’s Groundwater/Waste Management Committee. The SSAB reviewed
the 2016 EPA technical support documents for PFOA and PFOS and reviewed the
technical basis for PFOA and PFOS standards in other states and other countries. At
its December 2nd meeting, the SSAB heard overviews of studies conducted by
researchers in North Carolina and elsewhere since the EPA 2016 Drinking Water
Health Advisory values were established for 70 ng/L (ppt) for each chemical
individually and their additive value.
It was acknowledged that EPA’s Health Advisory work was developed with rigorous
scientific peer review and remains relatively current. The only concerns expressed
were: 1) the value of reviewing mammalian toxicology studies published since those
available during EPA's review (which used scientific literature through December
2015), 2) the value of examining the points of departure used in other entities' PFOA
and PFOS hazard assessments, and 3) there are many other PFAS chemicals to
which people may be exposed that would remain unaddressed in setting a 70 ng/L
standard for just two PFAS chemicals (however, it was acknowledged that there are
not health advisory levels for all of the relevant PFAS chemicals and there is not
consensus on which could be grouped based on similar toxicity mechanism(s) that
would lend to having their concentrations added to PFOA and PFOS for a standard
based on their values in total).
The SSAB members present voiced consensus on the establishment of a
toxicological science-based standard for PFOA and PFOS in preference to a
Practical Quantitation Level value*. A majority of members present indicated using
the EPA 2016 Drinking Water Health Advisory level was a reasonable step to
improve the current situation of having a much higher IMAC for PFOA of 2,000 ng/L
and no standard for PFOS. Members strongly voiced a recommendation for DEQ to
continue to evaluate research (with an emphasis on mammalian toxicity studies and
epidemiological data published after 2015) during the anticipated yearlong
rulemaking process to determine if a lower value is warranted, and to make these
chemicals a high priority for revisiting their standard(s) by monitoring the work being
done by other states in addition to EPA, using a shorter timeframe than the normal
triennial evaluation.
*For other PFAS compounds, for which such data are lacking, the PQL is an appropriate
approach.
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Attachment A
Regulatory Impact Analysis
Rule Citation: 15A NCAC 02L .0202
Rule Title: Groundwater Quality Standards
DEQ Division: Division of Water Resources (DWR)
Staff Contacts: Bridget Flaherty, Groundwater Standards Coordinator, DWR [e-mail] [phone]
Julie Ventaloro, Economist, DWR
[e-mail]
[phone]
Impact Summary: State government: Yes NC DOT: Yes
Local government: Yes
Federal government: Yes Private entities: Yes Substantial Impact: Unknown; net benefit expected
1.Necessity for Rule Change
North Carolina is required by N.C. General Statute 143-214.1 and N.C. Administrative CodeSubchapter 15A NCAC 02L to adopt groundwater quality standards to protect the use of
groundwater as a source of drinking water. Further, the Division of Water Resources (DWR) is
required by Rule 15A NCAC 02L .0202(g) to evaluate and revise, as necessary, these standardsevery three years. This process is known as the “triennial review.” The 2016 triennial review hasbeen completed, and DWR has identified 47 contaminants for which standards should be adoptedsuch that the rule will reflect the most recent health and toxicological information. As research
supporting our understanding of the human health effects of contaminants found in groundwater
advances, updating the groundwater standards ensures that cleanup requirements are set at a levelthat minimizes the risk that private well water consumers (including sensitive subgroups) willexperience adverse health effects over a lifetime of exposure without being unduly burdensomefor site owners.
2.Purpose of Rule
In accordance with Rule 15A NCAC 02L .0103(a), the purpose of the rules established inSubchapter 15A NCAC 02L is to “maintain and preserve the quality of the groundwaters, prevent
and abate pollution and contamination of the waters of the State, protect public health and permit
management of the groundwaters for their best usage by the citizens of North Carolina.”Historically, the North Carolina Environmental Management Commission (EMC) has consideredthe best usage of groundwaters of the State to be as a source of drinking water.
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Attachment B

The groundwater quality standards (hereafter referred to as “the standards” or “groundwater
standards”) for the protection of the groundwaters of the State are codified in subject Rule 15A NCAC 02L .0202. These standards represent the maximum allowable concentrations resulting from any discharge of contaminants to the land or waters of the State that may be tolerated without creating a threat to human health or that would otherwise render the groundwater unsuitable for its
intended best usage. The standards are used by various State regulatory programs to protect
groundwater as a source of drinking water. The standards should not be confused with “maximum contaminant levels” (MCLs) which are established as part of the federal Safe Drinking Water Act and apply only to the treated drinking water supplied by public drinking water systems.
The EMC is proposing to adopt groundwater quality standards for 47 contaminants. The proposed
standards are based on the most current available toxicological information and other relevant health risk assessment data in accordance with the criteria for establishing groundwater standards found in 15A NCAC 02L .0202(d), (e), and (f). 2.1 Regulatory Programs that use the Groundwater Standards
The groundwater standards are used primarily by the following State regulatory programs to establish target cleanup levels:
• Brownfields (NC DEQ-DWM)
o reuse of abandoned or underutilized contaminated property;
• Underground Storage Tanks (NC DEQ-DWM)
o regulates USTs that store petroleum or certain hazardous substances;
o closure activities and corrective actions to address spills and releases from USTs;
• Superfund (NC DEQ-DWM)
o monitoring and remediation of hazardous substance and waste disposal sites;
o includes the Inactive Hazardous Sites program, which addresses contamination at more than 1,900 chemical spill or disposal sites and about 700 landfills that
operated prior to 1982;
o includes the Dry-cleaning Solvent Cleanup program, which addresses contamination at dry cleaner sites;
• Solid Waste (NC DEQ-DWM)
o permitting and compliance of solid waste facilities that include municipal solid
waste landfills, industrial waste landfills, and construction/demolition waste landfills;
• Hazardous Waste (NC DEQ-DWM)
o prevention of hazardous substance release;
o groundwater monitoring to determine extent of contamination;
o cleanup of contaminated sites;
• Non-Discharge (NC DEQ-DWR)
o permitting of wastewater treatment and disposal/reuse systems while avoiding discharge to surface waters;
o includes wastewater irrigation, high-rate infiltration, residuals management;
• Groundwater Protection (NC DEQ-DWR)
o permitting and monitoring of injection, remediation, and recovery wells as well as some high capacity drinking water wells.
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• Asphalt Testing Program (NC DOT)
o under the Roadside Environmental Unit, perform on-site testing of asphalt for Department construction activities. 3. Regulatory Baseline

As part of the permanent rulemaking process, North Carolina General Statute 150B-19.1 requires agencies to quantify to the “greatest extent possible” the costs and benefits to affected parties of a proposed rule. To understand what the costs and benefits of the proposed rule changes would be to regulated parties, it is necessary to establish a regulatory baseline for comparison. For the
purpose of this fiscal note, the following items are considered to comprise the baseline:
• the current version of Rule 15A NCAC 02L .0202 (effective March 6, 2018);
• the Practical Quantitation Limit for each contaminant (Table 1). This is consistent with 15A NCAC 02L .0202(c) which states that “substances which are not naturally occurring and for which no standard is specified shall not be permitted in concentrations at or above the practical quantitation limit. . . .”
Practical Quantitation Limit -- or “PQL” -- is defined in 15A NCAC 02L .0201 as “the lowest concentration of a given material that can be reliably achieved among laboratories within specified limits of precision and accuracy by a given analytical method during routine laboratory analysis.”
Rule 15A NCAC 02L .0202 (b)(3) further clarifies: “Where naturally occurring substances exceed the established standard, the standard shall be the naturally occurring concentration as determined by the Director.” Of the 40 organic contaminants in this rulemaking, none are considered “naturally occurring” and none have a standard already adopted; therefore, the PQL is the regulatory baseline for the 40 organic contaminants. Of the seven metal/inorganic
contaminants, all seven can be found in their elemental form in the environment. Where these metals are found in groundwater at levels above natural background concentration, it is typically the result of anthropogenic inputs such as from industrial processes. For this reason, it is assumed that none of these metals will be found at natural background concentrations greater than their corresponding PQL. As such, the PQL will also be considered the regulatory
baseline for all seven inorganic/metal contaminants. The majority of PQLs used as the baseline in this analysis were established by either the DEQ Water Sciences Laboratory1 or by commercial laboratories that have been certified by DEQ. PQLs were sought from commercial laboratories only for those contaminants for which a PQL
was not available from the DEQ Water Sciences Laboratory.
PQLs can vary from laboratory to laboratory as well as within a laboratory based upon equipment used or other factors such as matrix effects and dilution; for this reason, we compared PQLs from several of the larger commercial laboratories certified by DEQ. In most
1 For PQL values: NCDEQ Chemistry Laboratory “QA/QC Limits PQLs”
https://files.nc.gov/ncdeq/Water+Quality/Chemistry+Lab/Operations/Quality+Assurance/NCDENR_DWR_WSS_LAB_PQLs.pdf
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cases, the PQLs reported by commercial laboratories for a given contaminant were uniformly
higher or lower than our proposed standard; in those cases, we concluded that the selection of
a PQL from a particular laboratory over another would have no effect on the impact of the proposed rule. For a handful of contaminants, there was more variability between PQLs reported by different
commercial laboratories. In the case of acetic acid, for example, one lab reported a PQL of
1,000 µg/L and another reported a PQL of 10,000 µg/L. In these cases, we considered the lowest reported PQLs as the regulatory baseline from which to compare the potential effects of our proposed standards. We reasoned that the lowest PQL best represented the capability of commercial laboratories and would be more typical of current regulatory requirements.

There were three contaminants for which a PQL was not available from either the DEQ Water Sciences Laboratory or a DEQ-certified commercial laboratory. For 1,4-dibromobenzene, we used a PQL from the DEQ Water Sciences Laboratory for the chemically-similar contaminant bromobenzene2. For acetochlor ESA and acetochlor OXA, we substituted the Lowest Concentration Minimum Reporting Level (LCMRL) as reported in EPA Method 5353 for the
PQL. As described in EPA 815-R-11-001 the LCMRL “represents an estimate of the lowest concentration of a compound that can be quantitatively measured by members of a group of experienced drinking water laboratories.” It is important to note that Interim Maximum Allowable Concentrations (IMAC) have been
established, per Rule 15A NCAC 02L .0202, for 44 of the 47 contaminants proposed for adoption; however, because IMACs are established on a temporary basis by the Director of DWR -- and not through the permanent rulemaking process -- they are not considered the regulatory baseline. The estimated fiscal impact of the proposed rulemaking would likely be considerably reduced in most cases if this analysis were to take into account the 44 existing
IMACs when these health-based values are higher than the PQL. The contaminants for which there is not an existing IMAC are: 2,6-dinitrotoluene; perfluorooctane sulfonic acid (PFOS); and strontium. There are five contaminants for which the proposed standard is lower than the IMAC:
acetochlor ESA, acetochlor OXA, 2,4-dinitrotoluene, n-butanol, and perfluorooctanoic acid (PFOA). Compared to the current IMACs, these proposed standards could potentially increase remediation costs at sites for which one or more of these contaminants is the driver. The impact of the proposed standards in relationship to the IMACs for these contaminants is summarized in Section 7; however, the main focus of this analysis is the impact as compared
to the PQLs. The North Carolina Office of State Budget and Management considers the PQLs to be the regulatory baseline because of the temporary nature of the IMACs and their creation outside of the rulemaking process. Generally, temporary rules are not part of the regulatory baseline because of their time-limited status and because they have not been subject to the
2 For identification of chemically-similar contaminant to 1,4-dibromobenzene: U.S. EPA Chemistry Dashboard
https://comptox.epa.gov/dashboard/dsstoxdb/results?search=DTXSID4024012#similar-molecules 3 For LCMRL values for Acetochlor ESA and OXA: U.S. EPA Document # EPA/600/R-05/053 “Method 535. Measurement of Chloroacetanilide and other Acetamide herbicide degradates in drinking water by solid phase extraction and liquid chromoatography/tandem mass spectrometry (LC/MS/MS)” Version 1.1, April 2005, J.A. Shoemaker, M.V. Bassett
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permanent rulemaking process, particularly economic analysis, public comment, and external
review.
4. Proposed Changes to the Baseline The only proposed changes to the subject rule are the adoption of standards for the 47
contaminants listed in Table 1. No changes are proposed to the existing standards already in rule.
Of these 47 contaminants, 7 are metals/inorganics and 40 are organics. They include pesticides/herbicides, petroleum products/fuels, and chemical manufacturing/industrial solvents. Most have multiple uses that cross industries and regulatory programs.
Table 1: Groundwater Standards Proposed for Adoption
Contaminant
Proposed Standard µg/L (ppb)
PQL
all reported in µg/L (ppb)
Is the proposed standard ≤ PQL?
State Lab
Certified Commercial Lab
Based on LCMRL #1 #2 #3 #4 #5
Metals/Inorganics
antimony and compounds 1 10 Yes
beryllium and compounds 4 5.0 Yes
cobalt and compounds 1 50 Yes
strontium and compounds 2,000 10 No
thallium and compounds 2 2.0 Yes
tin (inorganic forms) 2,000 10 No
vanadium and compounds 7 10 Yes
Organics
acetic acid 5,000 1,000 10,000 No
acetochlor 100 4.0 No
acetochlor ESA 500 0.4 No
acetochlor OXA 500 0.5 No
acetophenone 700 4 10 10 2 10 No
acrolein 4 5 20 10 100 10 Yes
alachlor 2 4 6 Yes
aldrin 0.002 0.03 Yes
benzyl alcohol 700 30 No
bromomethane 10 2 No
n-butanol 590 50 250 50 No
sec-butanol 10,000 5,000 5,000 250 No
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Contaminant
Proposed Standard µg/L (ppb)
PQL
all reported in µg/L (ppb)
Is the proposed standard ≤ PQL?
State Lab
Certified Commercial Lab
Based on LCMRL #1 #2 #3 #4 #5
4-chlorotoluene 24 1 No
dalapon 200 5 5.0 4 No
1,4-dibromobenzene 70 1+ No
dichloroacetic acid 0.7 1.0 1 Yes
p,p’-DDE 0.1 0.03 No
2,4-dichlorophenol 0.98 10 Yes
2,4-dinitrotoluene 0.05 10 Yes
2,6-dinitrotoluene 0.05 10 Yes
dinoseb 7 0.6 No
diphenyl ether 180 10 10 10 2 No
diquat 20 2.0 No
endosulfan sulfate 40 0.03 No
endothall 100 10 20 No
alpha-
hexachlorocyclohexane
0.006 0.04 0.0013 0.01 0.02 No
beta-hexachlorocyclohexane 0.02 0.04 0.0013 0.01 0.02 No
2-hexanone 40 10 10 5 10 10 No
4-isopropyltoluene 25 1 No
methyl isobutyl ketone 100 10 10 10 10 No
methyl methacrylate 25 5 2.0 2 5 10 No
1-methylnapthalene 1 1.6 0.8 10 0.5 1 No
2-methylphenol 400 10 No
perfluorooctane sulfonic acid (PFOS) and
perfluorooctanoic acid (PFOA) (Total)
0.07 0.002 0.002 2 0.002 No
Propylene glycol 100,000 50,000 10,000 10,000 10,000 No
1,2,4,5-tetrachlorobenzene 2 5 10 10 2 10 Yes
1,1,1,2-tetrachloroethane 1 1 Yes
1,1,2-trichloroethane 0.6 1 Yes
2,4,5-trichlorophenol 63 10 No
2,4,6-trichlorophenol 4 10 Yes
+ PQL for chemically-similar compound bromobenzene; Values shown in bold indicate regulatory baseline for purposes of this fiscal analysis, as described in Section 3.
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5. Human Health Outcomes and the Environment

The contaminants for which we are proposing standards are encountered in the environment at a wide range of sites. These sites can include chemical industry, furniture industry, abandoned hazardous waste, landfills, metalworking, wood treating, printing, plating, asphalt testing, and military facilities. We encounter solvents at furniture manufacturing and restoration, textile, wood
treating, landfill and paint and printing sites. We encounter pesticides, herbicides, intermediates
and solvent carriers at sites where agricultural chemicals have been stored, disposed or spilt during mixing. Metals are frequently found in groundwater at metal working, finishing, and plating sites. In addition to direct releases, some contaminants change the chemistry of the subsurface and mobilize naturally-occurring metals.

One tool we use to help protect groundwater from this ubiquitous usage and potential discharge of chemicals is the set of groundwater standards codified in Rule 15A NCAC 02L .0202. These standards are adopted to prevent chemical contamination of the groundwaters of the state so that they can be suitable for use as a source of drinking water.
Because the standards are established for the protection of waters that may be used for human consumption, it is critical to consider how the proposed standards could affect public health outcomes. The population that is potentially most directly affected by a change to the standards are the over three million North Carolina residents who use self-supported domestic water (i.e., wells)4. The residents who rely on public groundwater supplies are not covered by this analysis
because the North Carolina groundwater standards are not applicable to these systems. Public drinking water systems are regulated under separate federal “maximum contaminant levels” (MCLs). All of the groundwater standards proposed in this rulemaking are supported by the most recent
health effects data or odor and taste thresholds published by the U.S. Environmental Protection Agency (EPA) or other relevant peer-reviewed, published data. For example, when developing standards, DWR often consults EPA’s Integrated Risk Information System (IRIS) database. The IRIS database provides high-quality risk assessments that detail the potential human health effects of hundreds of different chemicals and provide toxicological information necessary to develop
standards that are protective of human health. The majority of this regulatory impact analysis is concerned with quantifiable and non-quantifiable costs and benefits to regulated parties and government agencies. In order to consider these economic impacts, we had to establish a regulatory baseline. Discussed in Section 3, the
regulatory baseline we used is the Practical Quantitation Limit, or PQL. The PQL is a technology-based value used by laboratories to communicate their confidence in their test results. The PQL is not based on health effects data; as such, it should not be compared to a groundwater standard for purposes of determining human health impacts.
To further explain, in this analysis we compare the proposed groundwater standards to the PQLs when considering costs to regulated parties. This is because the adoption of the standard will replace the PQL as the regulatory baseline – the standard and the PQL can be compared when
4 For estimated number of private groundwater well users in North Carolina: https://epi.dph.ncdhhs.gov/oee/wellwater/figures.html
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looking at regulatory effects. But it would not be appropriate to compare the standards to the PQL
when considering human health effects because the standard is a health- or aesthetics-based value
and the PQL is not. The PQL does not inform the level of human health protection of the standard. Some of the proposed standards in this rulemaking are numerically higher than the PQL and may
therefore provide some measure of regulatory relief. Although providing regulatory relief, the
higher standards will not adversely affect health outcomes of consumers of well water. This is because neither the PQLs nor the proposed standards surpass the risk management levels established in Rule 15A NCAC 02L .0202(d). For example, for p,p’-DDE (a breakdown product of commercial pesticide DDT, a known carcinogen) the PQL is 0.03 µg/L and the proposed
standard is 0.1 µg/L. Although the standard is higher than the PQL, and that could provide
regulatory relief, neither the PQL nor the standard surpasses the lifetime cancer risk of one in a million, as required by Rule 15A NCAC 02L .0202(d)(2). In this context, the two values can be considered equivalent as far as managing lifetime cancer risk. In another example, the PQL for dinoseb (an herbicide known to be toxic, but not classified as a carcinogen) is 0.6 µg/L and the proposed standard is 7 µg/L. For this contaminant, the PQL and the higher standard can be
considered equivalent in that neither value surpasses the systemic threshold concentration as required by Rule 15A NCAC 02L .0202(d)(1). In other words, there would not be an increase in the appreciable risk of deleterious effects during a lifetime from daily exposure at either level. In both scenarios, the cleanup goals established using the technology-based PQLs provided a conservative level of protection that exceeded the point at which there would be no observable
effects to the population. Therefore, setting a numerically higher standard that reflects a risk management threshold will not increase risk to public well water consumers. In short, adoption of these standards will reduce unnecessary regulatory burdens to owners of contaminated sites while maintaining at least an equivalent level of environmental, aesthetics, and human health protection.
The regulatory relief associated with this rulemaking could, in fact, provide an indirect benefit to the environment and human health. For some programs, regulatory relief will result in savings to funding sources for remediation projects. This would make funding available to more contaminated sites which would ultimately improve groundwater protections for consumers of private well water. 6. Costs and Benefits Analyses 6.1 Standards less than (or equal to) the PQL Rule 15A NCAC 02L .0202(b)(1) states: “Where the standard for a substance is less than
the practical quantitation limit, the detection of that substance at or above the practical quantitation limit constitutes a violation of the standard.” Of the 47 standards proposed in this rulemaking, 16 are lower than (or equal to) the PQL (Table 2). For these 16 contaminants, the PQL will remain the regulatory baseline upon adoption of the standards, and the adoption of standards will neither increase nor decrease regulatory requirements.
As discussed in Section 5 of this document, the adoption of these standards will not change the level of environmental or public health protection already in effect.
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For these reasons, the adoption of the 16 standards in Table 2 should have no quantifiable
impact on regulated persons, at least for the foreseeable future, and no impact on public
health outcomes. Table 2: Proposed Groundwater Standards that are Less than (or equal to) the PQL

Contaminant
Metals/Inorganics
antimony and compounds
beryllium and compounds
cobalt and compounds
thallium and compounds
vanadium and compounds
Organics
acrolein
alachlor
aldrin
dichloroacetic acid
2,4-dichlorophenol
2,4-dinitrotoluene
2,6-dinitrotoluene
1,2,4,5-tetrachlorobenzene
1,1,1,2-tetrachloroethane
1,1,2-trichloroethane
2,4,6-trichlorophenol
It is likely that environmental chemical testing methods and technologies will improve for some or all of these 16 contaminants over time, thereby allowing laboratories to achieve
lower PQLs. In the event that a PQL is achieved that is lower than the standard, the
standard would replace the PQL as the regulatory baseline. At that point, the standard would provide regulatory relief which could result in cost savings for remediation, monitoring, and permitting. It is impossible, however, to predict how fast – or how much – testing technology will improve for a given contaminant, so we have not attempted to
quantify this possible future impact. 6.2 Standards greater than the PQL Of the 47 standards proposed in this rulemaking, 31 are greater than the PQL (Table 3). Unlike the 16 standards that are less than the PQL (Table 2), these 31 standards will
replace the PQL as the regulatory baseline upon adoption of the rule. For purposes of this
analysis, the adoption of these 31 standards will reduce unnecessary regulatory burden. As a result, there should be some economic benefit and no economic cost to regulated parties.
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The proposed standards are health-based values that take into account lifetime risks to
human health from consumption of a contaminant. Neither the PQLs nor the proposed
standards surpass the risk management levels established in Rule 15A NCAC 02L .0202(d). As such, the proposed standards are considered at least as protective of the environment, aesthetics, and human health as the technology-based PQL values.
Table 3: Proposed Groundwater Standards that are Greater than the PQL

Contaminant
Metals/Inorganics
strontium and compounds
tin (inorganic forms)
Organics
acetic acid
acetochlor
acetochlor ESA
acetochlor OXA
acetophenone
benzyl alcohol
bromomethane
n-butanol
sec-butanol
4-chlorotoluene
dalapon
1,4-dibromobenzene
p,p’-DDE
dinoseb
diphenyl ether
diquat
endosulfan sulfate
endothall
alpha-hexachlorocyclohexane
beta-hexachlorocyclohexane
2-hexanone
4-isopropyltoluene
methyl isobutyl ketone
methyl methacrylate
1-methylnapthalene
2-methylphenol
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Contaminant
perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) (Total)
propylene glycol
2,4,5-trichlorophenol
For contaminants in Table 3, there should be some economic benefit to regulated parties
from having the regulatory threshold lowered. This benefit would be realized by those
regulated parties for whom one (or more) of the contaminants listed in Table 3 is a main driver for their site remediation. For purpose of this analysis, driver contaminants are contaminants that are either potentially widespread or have the greatest economic cost in cleanup of sites.

As mentioned earlier, there are Interim Maximum Allowable Concentrations (IMACs) already in effect for 44 of the 47 contaminants. This includes all but two of the contaminants in Table 3: Strontium and compounds and PFOS. In practice, the regulatory requirement (i.e., cleanup goal) for contaminants with an approved IMAC is the IMAC;
however, because we are considering the PQL – not the IMAC – as the baseline for this
analysis, we must compare the economic impact of the proposed standard against the PQL. At the same time, we recognize that because there are existing IMACs, the bulk of the benefit we report should be considered an ongoing benefit rather than a benefit that will
begin at some point in the future. In other words, we are attempting to quantify the
ongoing benefit to the regulated parties from the adoption of the standard as compared to the PQL, absent the IMAC. Many of the regulatory programs that are subject to the groundwater standards use the
standards in similar ways. It makes sense, then, that those programs for which one or more
of the contaminants in Table 3 are the driver contaminants might benefit in similar ways. Monetizing these benefits was challenging for many of these programs, though, due to the degree of variability between sites, unpredictability of future contaminant levels, lack of available data, and the complex nature of groundwater remediation. We quantified impacts
when possible, but more often, we described the impacts in qualitative terms. 6.2.1 Benefits, in general During preparation of this document, it became evident that a number of our regulatory programs would potentially benefit (or are already benefiting) in similar
ways from the proposed standards. Benefits that can be generalized to multiple programs are listed below. Additional benefits (or lack thereof) specific to each regulatory program are discussed in greater detail under the programs’ respective headings.
If a cleanup goal for a contaminant is relaxed (i.e., standard > PQL), and that contaminant is a driver for either monitoring or cleanup requirements, then the
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responsible party for a regulated site may benefit in one of more of the following
ways:

• Reduced frequency of monitoring: cost savings would include the labor costs to sample monitoring wells, analytical costs, and the costs of mapping and reporting results to DEQ. Decisions to allow reduced frequency of monitoring
will be made by regulatory staff on a case-by-case basis.
• Reduced number of contaminants being monitored: costs saved include the cost to analyze the samples. Analytical costs vary widely by contaminant and laboratory.
• Reduced number of groundwater wells being monitored: costs saved include the cost to sample the well (labor costs). The cost savings realized by ceasing monitoring at a well will be somewhat reduced in the short term by the one-time costs associated with closing the well. Sites such as landfills, inactive
hazardous waste sites, and USTs will incur these well closure costs at some
point in time, regardless of the standard. But a numerically-higher standard may result in those costs being incurred years earlier.
• Reduced cleanup time: cost savings from completing groundwater
remediation in a shorter period of time would largely be from spending less on
operation and maintenance of the cleanup technology. These costs can be
substantial and would likely make up the largest portion of cost savings realized from the proposed standards.
• Use of a more cost efficient cleanup technology: the type of technology used
to reduce contaminant levels to the groundwater standard is site specific and
depends on factors such as number and types of contaminants, contaminant properties, extent of contamination, hydrogeologic properties (soil and rock type), and cleanup goals. These factors, including the type of cleanup technology used at a site, will affect the time and cost to clean up groundwater.

The State agencies responsible for providing oversight of these regulatory programs could also realize potential benefits by freeing up staff capacity or funding resources that will be reinvested to address currently unmet needs:
• Regulated sites that achieve compliance with groundwater standards earlier –
perhaps years earlier -- will require significantly less staff time in terms of oversight over the long term. This will reduce staff time spent on reviewing reports, analyzing data, and preparing correspondence per site. It will also result in the need for less travel to perform each site visit, which will save on
fuel and vehicle maintenance costs. However, any savings to staff time and resources due to one project’s early completion will be immediately reinvested to address the large backlog of other sites in need of staff attention across the state. For this reason, we did not expect any direct budgetary savings.
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6.2.2 Brownfields
None of the contaminants in Table 3 are known drivers for cleanup of Brownfields
sites. As such, the proposed standards would not have any economic impact on parties regulated under this program. 6.2.3 Hazardous Waste
The primary purpose of the Hazardous Waste Section of DEQ is to prevent and
reduce releases of hazardous waste and to clean up contaminated sites. Sources of hazardous waste can include, but are not limited to, industrial or manufacturing processes such as wood preservation, chemicals manufacturing, petroleum refining, pesticides manufacturing, iron and steel production, and explosives manufacturing.
Hazardous waste can also come from discarded common household products such
as batteries, fluorescent lightbulbs, cathode ray tubes, paint thinners, herbicides, and adhesives. In North Carolina, sites with groundwater contaminated by hazardous waste are required to cleanup to the groundwater standard or, in the absence of a standard, to
the PQL. Of the contaminants in Table 3, the Hazardous Waste Section identified only one proposed groundwater standard that could potentially result in a cost impact to regulated hazardous waste sites: perfluorooctane sulfonic acid (PFOS) + perfluorooctanoic acid (PFOA) (Total). PFOS and PFOA are commonly-used man-made chemicals that have been used in manufacturing of fabrics, food
packaging, carpet, and cookware. They are also present in aqueous film-forming foam (AFFF) which is used as a fire suppressant at military bases, fire training facilities, and airports and as a chemical fume suppressant at some types of industrial facilities.
The proposed standard for PFOS and PFOA is based on U.S. EPA drinking water health advisories5 for PFOS and PFOA. These advisories considered the best available peer-reviewed laboratory studies of the health effects of these contaminants on rats and mice and also incorporated information from epidemiological studies from incidents of human exposure to these contaminants.
Due to similarities in adverse effects that were observed following exposures to PFOS and PFOA and numerically-identical toxicity values, U.S. EPA recommends comparing the combined concentrations of PFOS and PFOA to the published health advisories. Therefore, the proposed groundwater standard for PFOS and PFOA will apply whether these contaminants are found individually or in combination.
For purposes of this analysis -- which relies on the PQL being the regulatory baseline in the absence of a standard – the proposed groundwater standard for PFOS + PFOA (Total) could provide some economic relief to regulated parties for which one or both of these contaminants is the driver for cleanup. The Hazardous
Waste Section identified only one site -- a privately-owned chemical manufacturer -- at which PFOS or PFOA is driving groundwater cleanup. Two other sites are
5 For determination of combined PFOS/PFOA groundwater standard: U.S. EPA drinking water health advisory https://www.epa.gov/ground-
water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos
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currently required to sample for PFOS and PFOA – another privately-owned
chemical manufacturer and a municipal-owned fire training facility; however,
cleanup at these sites is not driven by the presence of PFOS or PFOA, so they are not expected to be impacted by the numerically higher standard. Estimates of potential cost savings from the numerically higher standard were not
provided for the one chemical manufacturing site. In the absence of quantifiable
data for the one hazardous waste site, the general benefits summarized in Section 6.2.1 are applicable. The Hazardous Waste Section stated, though, that they do not expect an appreciable economic impact from adopting the proposed standard.
If we were to take into consideration the existing IMAC for PFOA, the potential
regulatory benefit from the proposed combined standard would be reduced, eliminated, or possibly reversed. The size of the effect would depend, in part, on which of the contaminants -- PFOA or PFOS – is the driver contaminant. The IMAC for PFOA, which serves as the cleanup goal in practice, is 2 µg/L. For PFOS, there is no IMAC so the cleanup goal is the PQL, which is 0.002 µg/L. The
proposed combined groundwater standard for PFOS + PFOA (Total) is 0.07 µg/L, which falls between the current cleanup goals for the two constituents. Because the cleanup goals for these two constituents are being combined into one standard -- and that standard is higher for one contaminant and lower for the other -- the Hazardous Waste Section expects potential benefits from the higher PFOS standard
to be offset by the potential costs from the lower PFOA standard. With that being said, we do not have enough information to predict whether the costs and benefits would be offset equally or whether there could be some net costs or net benefits. That would depend on factors that will vary from site to site such as whether one or both contaminants are being monitored, their relative concentrations, the scale and
complexity of the remediation, and the available remediation technology. We also considered whether there could be an outsized regulatory effect due to the fact that the PFOA cleanup goal is changing by a larger order of magnitude than the PFOS cleanup goal. We concluded that assumptions based on differences in order
of magnitude would be overly speculative because of the variability between sites, unpredictability of future contaminant levels, lack of available data, and the complex nature of groundwater remediation. Data was not available to monetize these various cost and benefit scenarios. 6.2.4 Superfund The potential impacts on parties regulated under Superfund are as follows: 6.2.4.1 Dry Cleaning Solvent Cleanup None of the contaminants in Table 3 are known drivers for cleanup of dry
cleaning solvent sites. As such, the proposed standards would not have any economic impact on parties regulated under this program.
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Inactive Hazardous Waste
The Inactive Hazardous Sites Program addresses sites contaminated with
hazardous substances not related to permitted discharges. These are referred to as “inactive” sites because the original industries at the sites are generally no longer operating. Releases from these sites occurred before there were regulations prohibiting such releases. Some are the result of
newer product spills. Most of these sites have since gone out of business or
reorganized, making it difficult or impossible to find financially-viable responsible parties to do remediation. Compounding the complexity of remediating these sites is the lack of documentation regarding how, where, and when the release or releases occurred.

The Inactive Hazardous Sites Branch (IHSB) reported that, as of June 2019, there were 2,561 open IHSB cases. Of these, 666 were old landfills that received hazardous wastes before there were any regulations. The other 1,895 are non-landfill sites. IHSB estimated that about 80% of the non-landfill sites are orphaned, which means they are left to the State to manage
and pay for remediation, as funding allows. Of the 2,561 open cases, only about 13% are being remediated using private funds. In addition to the State-funded and privately-funded sites, there are 75 inactive hazardous sites for which the federal government (EPA and
Department of Defense) has responsibility under the Superfund Program. These are the sites on the National Priority List which are considered the most hazardous waste sites. Figure 1: Responsible Parties for Inactive Hazardous Waste Sites

Remediation of hazardous waste sites is costly, some sites costing in the millions of dollars. For the landfills, DEQ receives funding from the
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
State Private Sector Federal
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statewide solid waste disposal tax. For the remaining orphaned sites, DEQ
receives only $400,000 per year. Because of this large funding shortfall for
orphaned sites, many of them are uncontrolled and have multiple hazards with limited investigation completed. Table 4 lists the chemicals (from the subset in Table 3) that IHSB reported
are commonly found at inactive hazardous waste sites, and for which the
proposed standards would potentially provide some cost savings. Table 4: Contaminants found at Inactive Hazardous Waste Sites
4-chlorotoluene 2-methylphenol
endosulfan 2,4,5-trichlorophenol
methylnaphthalene p,p’-DDE

Staff stated that 4-chlorotoluene would probably have the highest impact in terms of reducing remediation costs as that can be one of the driver contaminants. Every site is different in terms of which contaminants are present, the degree of contamination, and the scale and complexity of remediation required to meet groundwater standards. It follows that the
cost for remediation is extremely variable. For this reason, we did not attempt to monetize the potential cost savings of the proposed standards. It is reasonable, however, to assume that sites with a driver contaminant such as 4-chlorotoluene could see a significant cost savings over the life of the
remediation, which typically spans decades.
It is assumed that all types of inactive hazardous waste sites for which the State has responsibility, including landfills, have the potential to realize some amount of cost savings:

• Cost savings for cleanup of non-landfill orphaned sites and landfills would be realized by both DEQ as the regulator and by the taxpayer. DEQ would see cost savings from reduced staff time and resources
needed for oversight of the sites’ cleanup. This includes savings
from performing fewer site visits and spending less time reviewing reports and preparing correspondence. This ultimately benefits the state taxpayer.
• Cost savings to landfills will translate into savings to the statewide
solid waste disposal tax fund, leaving more funding available for remediation at landfills.
• The private sector could realize a direct benefit from cost savings on their own sites.
• Sites for which the federal government has responsibility will likely realize a lesser benefit than State-managed sites. The reason for this is that the federal government manages sites involving the most
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hazardous contaminants, none of which are part of this proposed
rulemaking.
In the absence of quantifiable data, the general benefits summarized in Section 6.2.1 are applicable to all parties responsible for inactive hazardous waste sites.
6.2.5 Solid Waste Program Within the Solid Waste Program, the parties that might be impacted are the following types of landfills:
• Municipal Solid Waste (MSW) landfills - nonhazardous waste from household, commercial, and institutional sources;
• Construction and Demolition Debris (C&D) landfills – solid waste from
the construction, remodeling, repair, or demolition operations on pavement
and buildings or structures; and
• Industrial Waste (IW) landfills – solid waste from manufacturing or
industrial processes that is not a hazardous waste regulated under Subtitle C
of RCRA. Includes waste resulting from manufacturing processes such as electric power generation, fertilizer/agricultural chemicals, iron and steel manufacturing, organic chemicals, transportation equipment, etc. Does not include mining waste or oil and gas waste.

MSW and C&D landfills are required to perform groundwater monitoring for a suite of contaminants set by federal and state regulation. Which contaminants they monitor for depend primarily on the age of the landfill. Older landfills -- permitted before Oct 9, 1993 -- monitor groundwater for contaminants listed in 40 CFR Part 258 “Criteria
for Municipal Solid Waste Landfills” Appendix I “Constituents for Detection
Monitoring” (typically referred to as “Appendix I”)6. Newer landfills -- permitted on or after Oct 9, 1993 -- also monitor groundwater for Appendix I contaminants; however, if they have exceedances, they are required to do additional monitoring of contaminants in the “List of Hazardous Inorganic and Organic Constituents”
(“Appendix II”). If a contaminant is not listed on Appendix I or II, it is generally not
required to be monitored at MSW or C&D landfills, although there are occasional exceptions based on waste stream. IW landfills operate under a somewhat different groundwater monitoring scheme. In
addition to monitoring for Appendix I contaminants, IW landfills also monitor for
contaminants depending on the makeup of their specific waste stream. This results in greater variability between individual IW landfill facilities.
6 For determination of which contaminants are monitored at landfills: Appendix I and II referenced from NC Solid Waste Section Environmental Monitoring List, Oct 15, 2018 https://edocs.deq.nc.gov/WasteManagement/0/edoc/1257181/SWS_EnviroMonitoring_Constituents_List.pdf
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Table 4 summarizes the numbers and types of landfills at which each of the proposed
contaminants have been or are currently being monitored. It also states whether the
contaminant is listed in Appendix I or II. About two thirds of the proposed contaminants have been tested for in groundwater at one or more of the three types of landfills. According to DWM Solid Waste Section staff, changing waste streams and other variables at landfills make it difficult to identify when one contaminant over
another is the main driver for assessment or cleanup of contaminated groundwater.
This means that even if a proposed contaminant was detected at a level above the PQL, we cannot claim that the adoption of a standard that is numerically higher has or has not benefited these landfills. For this reason, we have not attempted to monetize the ongoing fiscal impact of the proposed standards on landfills.
Table 4: Proposed Contaminants Monitored at NC Solid Waste Landfills

Contaminant
Listed in
40 CFR Part 258
Appendix I or II?
Type & Number of Landfills
at which Contaminant
has been Monitored
Metals/Inorganics
strontium and compounds - IW -1
MSW - 2
tin (inorganic forms) Appendix II MSW-28
C&D-9
Organics
acetochlor ESA - none
acetochlor OXA - none
acetophenone Appendix II MSW-2
C&D-2
benzyl alcohol Appendix II MSW-3
bromomethane Appendix I none
n-butanol - none
sec-butanol - none
4-chlorotoluene - IW-4
dalapon - none
1,4-dibromobenzene - none
p,p’-DDE Appendix II MSW-4
dinoseb Appendix II MSW-5
diphenyl ether - IW-1
diquat - none
endosulfan sulfate Appendix II none
endothall - none
alpha-hexachlorocyclohexane - MSW-18
C&D-6
beta-hexachlorocyclohexane - MSW-15
C&D-4
2-hexanone Appendix I MSW-21
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Although about one third of the contaminants have not been monitored at these types of landfills, we cannot say with reasonable certainty that they will not be monitored in the future. Degradation of landfill materials over time or the development of a leak in
a liner could result in the detection of a previously-undetected contaminant. It is also
common for the makeup of materials collected at a landfill (waste stream) to vary over time. This could result in the introduction of additional contaminants to the groundwater and additional testing requirements. Further compounding the difficulty in monetizing a fiscal impact is that it is impossible to predict if future analytical
testing will detect higher levels or lower levels of a particular contaminant. For these
reasons, we have not attempted to monetize the future fiscal impact of the proposed standards on landfills. In the absence of quantifiable data, the general benefits summarized in Section 6.2.1
are applicable to all parties responsible for regulated solid waste landfills.
It is assumed that all regulated landfills could potentially benefit from a numerically- higher groundwater standard for the reasons stated above. This benefit could be
realized regardless of ownership. According to DWM, there were approximately 311
active and inactive MSW, C&D, and IW landfill facilities in North Carolina as of February 1, 20197. The majority of these types of landfills are owned either by private entities or local governments, although there is a total of seven landfills owned by state and federal governments (Table 5). We do not anticipate one type of landfill or
one subgroup of owner to benefit more than another.

7 For data on numbers of NCDWM Solid Waste permitted facilities: https://deq.nc.gov/about/divisions/waste-management/sw/data/facility-lists
C&D-5
IW-1
4-isopropyltoluene - MSW-3
IW-1
methyl isobutyl ketone Appendix I
MSW-34
C&D-5
IW-2
methyl methacrylate Appendix II MSW-8
1-methylnapthalene - none
2-methylphenol Appendix II MSW-3
perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) (Total) -
None*
*Leachate from lined landfills
will be tested beginning in 2019.
propylene glycol - none
2,4,5-trichlorophenol Appendix II MSW-2
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Table 5: Ownership of C&D, IW, and MSW Landfills in North Carolina

Privately-owned
Local Govt-owned
State-owned
Federal-owned
Sub-Total
C&D 34 51 0 1 86
Industrial 40 2 0 0 42
MSW 42 135 2 4 183
TOTAL 311

6.2.6 Underground Storage Tanks
The Underground Storage Tank (UST) Section of DEQ oversees programs related to the cleanup of contaminated soil and groundwater due to releases of contaminants from USTs. These sites are required to cleanup to the groundwater standard or, in the absence of a standard, to the PQL. Of the contaminants in Table 3, only those associated with petroleum products were identified by the UST
Section as potential contaminants of concern at UST release sites. This subset of contaminants is listed in Table 6. Table 6: Potential Non-Driver Contaminants at UST Sites
Benzyl alcohol Methyl isobutyl ketone
Bromomethane 1-methylnapthalene
n-Butanol 2-methylphenol
4-chlorotoluene Propylene glycol
2-hexanone 2,4,5-trichlorophenol
4-Isopropyltoluene
While each of the contaminants in Table 6 has the potential to be found at UST
sites, none of them are considered drivers for assessment and remediation of
petroleum releases. This is because other petroleum products -- such as MTBE and benzene – are usually the drivers as they are more widespread and have substantially greater cleanup costs. The contaminants in Table 6 are found in very small amounts, as additives or incidental contamination.

Although none of the proposed standards are for driver contaminants, we still anticipate some economic benefit to various parties from adopting standards that are numerically higher than the associated PQLs. Currently, when non-driver contaminants are found at levels above the PQLs, closeout of a UST remediation
site can be delayed. Under this scenario, soil excavation and groundwater cleanup
(e.g., pump and treat) activities will cease, but groundwater monitoring will continue until the site is closed out. Non-driver contaminants tend to be less volatile than the driver contaminants and are therefore harder to remediate, relying more on passive remediation techniques such as natural biodegradation and time.
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For example, if a site is successfully remediated for the driver contaminant (such as
MTBE) by soil excavation and treatment of groundwater, but levels of another
contaminant (such as 1-methylnapthalene) remain elevated above the PQL, excavation and treatment cease, but monitoring for the non-driver contaminants must continue. Adopting a standard that it numerically higher than the PQL should result in fewer instances and shorter durations of delayed closeouts.

The UST Section conservatively estimated that elevated levels of non-driver contaminants, such as those listed in Table 6, could delay closeout of UST petroleum release sites by as much as five years and affect up to 10% of active remediation sites annually. These are rough estimates based on decades of staff
experience and are solely meant to provide a basis for analysis. The actual duration
of closeout and number of sites affected is highly variable from site to site and year to year. Staff estimated that approximately 400 sites in a year achieve successful cleanup of the driver contaminant. It follows that the closeout of 40 sites (10%) might be delayed due to lingering presence of non-driver contaminants.
The largest portions of cleanup costs are associated with soil excavation, groundwater cleanup, and groundwater monitoring. Since soil excavation and groundwater cleanup are not factors for non-driver contaminants, those costs are not included in this analysis. The UST Section estimated that delaying closeout of one site could cost up to $10,000 per year for ongoing monitoring (sampling and
laboratory analyses). This is likely an overestimate for many sites, but it should provide a reasonable basis to consider the maximum possible cost for a complex site. Costs will be highly variable between sites due to differences in site-specific conditions, monitoring frequencies, and contaminants being tested.
The responsible parties for the majority of UST sites are private commercial entities (50.84%) or private non-commercial entities (36.74%). Responsible parties can include tank owners, operators, and landowners. A total of 5.54% of sites are owned by government entities, which include federal (e.g., military bases, post offices) state (NCDOT, prisons, hospitals), or local governments. The remaining
6.88% are State-lead sites, which are sites where the State assumes responsibility for remediation when the commercial responsible party cannot or will not perform remediation as required. Table 7: Responsible Parties of Active Storage Tank Sites in North Carolina

Responsible Party # Active
Sites
% Active
Sites
Commercial 7,045 50.84% Non-commercial 5,091 36.74%
State-lead 953 6.88%
Government-owned (state, local, federal) 768 5.54%
TOTAL 13,857 100%

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Over five years, it is assumed the responsible parties would receive a cost savings
proportional to the number of sites they own or operate. The one exception to that
is for commercial sites. Commercial sites have access to funds from the State’s UST Commercial Trust Fund dedicated to cleaning up contaminated UST sites. The net costs for commercial sites are limited to a $20,000 deductible per site, regardless of how extensive the remediation plan. After meeting the deductible,
commercial sites are eligible for reimbursement from the UST Commercial Trust
Fund for 100% of their expenses. Currently, the UST Commercial Trust Fund does not have enough funds to cover all the commercial remediation projects in a given year. As such, the North
Carolina General Assembly limits reimbursements to a subset of commercial UST
remediation sites that are ranked as having an Intermediate risk or greater to human health and the environment. Assessment and remediation work at the remaining commercial UST sites has been suspended indefinitely. These are sites that are not receiving reimbursement either because they are lower risk and are therefore ineligible or because the UST Commercial Trust Fund has insufficient funds to
reimburse all eligible projects in a given funding cycle. In the near term, the proposed rulemaking will be of little or no benefit to sites not eligible for funding (i.e., lower risk sites), but these sites may benefit in the long term as funding becomes available.
It stands to reason that the potential savings to commercial sites will be shifted to the UST Commercial Trust Fund. The UST Commercial Trust Fund will save money on current remediation sites, thereby leaving more money available for remediation of additional sites. In turn, cleanup of additional sites provides an indirect benefit to a localized subset of private well water consumers and the
environment in the form of improved groundwater protection. Aside from the subset of well water consumers who will benefit from savings to the UST Commercial Trust Fund, privately-owned non-commercial sites stand to benefit the most from the proposed standards as they are responsible for the vast majority of sites for which no such trust fund is available.
The UST Section Trust Fund Branch will realize cost savings due to reduced assessment, corrective action, and monitoring costs. This savings will be re-invested to address the substantial backlog of sites that need attention. Government-owned sites are not eligible for money from the State Trust Fund, so
the agencies themselves will realize direct benefits from reduced monitoring costs. Data was not readily available on the proportion of federal versus state versus local government-owned sites, so we assumed each government subgroup would benefit equally.
Table 8 presents the estimated maximum savings over the next 5 years for each responsible party subgroup and the benefit to the UST Commercial Trust Fund. These amounts were estimated as follows:
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Total savings for all parties over the 5 years:
40 sites per year x $10,000/year = $400,000 per year x 5 years = $2,000,000 ($1,754,884 Net Present Value, using 7% discount rate) The cost savings proportionate to each subgroup of responsible parties over 5 years was estimated as follows:
% of Active Sites x $1,754,884 / 100.
Table 8: Maximum Cost Savings for UST Responsible Parties Over Five Years in Millions of 2019 Dollars

Responsible Party % Active Sites Savings ($M)
UST Commercial Trust Fund 50.84% $0.8922 Non-commercial 36.74% $0.6447
State-lead commercial 6.88% $0.1207
Government-owned (state, local, and federal) 1.85% $0.03246 1.85% $0.03246
1.85% $0.03246
Commercial sites (see UST Trust Fund) $0
TOTAL
100%
$1.75498
rounded to $1.76M NPV
This is likely an overestimate for the reasons stated above as well as the fact that some sites might still experience some delayed closeout if contaminant levels remain higher than the new standard. The proposed standards for these contaminants were, in many cases, proposed by the UST Section in order to
provide regulated parties from relief from the numerically-lower PQLs. As such, it is reasonable to expect that a majority of sites will receive some benefit from the proposed standards in the form of reduced monitoring costs. More precisely, these sites will continue to receive some ongoing benefit from the proposed standards since the standards are already in effect as IMACs.
6.2.7 DWR Groundwater Protection Program 6.2.7.1 Hazardous Waste Injection Wells
Administered by DWR, the Groundwater Protection Program uses the groundwater standards for remediating sites in which hazardous waste was disposed of by injecting it into underground wells, a practice that is now prohibited. There are very few of hazardous waste injection well sites still under DWR oversight.

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The impact of the proposed standards on parties regulated under DWR’s
Groundwater Protection Program is expected to be negligible. Any
potential impact will be mitigated by Rule 15A NCAC 02L .0407 which allows remediation of groundwater contamination to either the groundwater standards or to a level that is “as closely thereto as is economically and technologically feasible.” It is unlikely, therefore, that the adoption of a
groundwater standard that is higher than the technology-based PQL would
provide a cost savings beyond that which is already allowed by this provision. In some cases, Rule 15A NCAC 02L .0407(c) requires remediation levels based on values other than the groundwater standards, such as IMACs, federal drinking water standards, or contaminant solubility.
Because the regulatory baseline for this program is varied and not limited to
the groundwater standard, we do not anticipate any economic impact on parties regulated under this program. 6.2.7.2 Non-discharge Sites DWR is authorized under Subchapters 15A NCAC 02L (Groundwater
Classification and Standards) and 15A NCAC 02T (Waste Not Discharged to Surface Waters) to issue permits that allow the discharge of waste onto land or into the subsurface under conditions outlined in a “non-discharge” permit. Infrequently, cleanup activities from these discharges may be required. Staff reported that there are no cleanup activities underway on
permitted sites for any of the 31 contaminants in Table 3, and none of the 31 contaminants are part of permittees’ required monitoring suite. For this reason, there is no data available to quantify how many non-discharge sites could potentially be affected. Staff indicated that of the proposed standards, only PFOS/PFOA is currently being considered for monitoring in the future.
Without data on current levels of PFOS/PFOA at these sites, or an estimate on how many sites would exceed the PQL for this contaminant, staff cannot speculate on many sites might benefit from a standard that is numerically higher than the PQL. For these reasons, we have not attempted to monetize the potential economic impact to current or future non-discharge permittees.
DWR’s Groundwater Protection Program anticipates no direct or indirect economic impact to their program from the proposed rule. 6.2.8 NC Department of Health and Human Services (NC DHHS)
The On-Site Water Protection Branch programs within NC DHHS provide oversight of sub-surface on-site wastewater treatment systems. They also provide consultative services related to wastewater and private drinking water wells to local health departments. They use the groundwater standards for non-regulatory purposes only. Staff confirmed that the proposed changes to the groundwater
standards should have no impact on their programs. 6.2.9 Agriculture Although some of these contaminants are products used in agriculture -- particularly pesticides (including herbicides) -- our standards will not affect the
B24
agricultural community. Use of herbicides in agriculture is regulated by different
criteria, typically lifetime Health Advisory Levels (HAL) or maximum contaminant
levels (MCL). Use of other types of pesticides is subject to other federal and state regulations and is not required to comply with EMC’s groundwater standards. DWR contacted the Department of Agriculture and Consumer Services who
reported no anticipated direct or indirect economic impact to the agency from the
proposed rule. 6.2.10 NC Department of Transportation (NCDOT)
The program within NCDOT that will be primarily affected is the Asphalt Testing
Program. The NCDOT Asphalt Testing Program performs on-site testing of asphalt for Department construction activities using ASTM Method D2172-88. This method requires the use of solvents. Solvents stored, spilled, or disposed of onsite near operating labs can result in releases of these solvents to the environment.
NCDOT identified four contaminants on our proposed standards list that have been detected in groundwater at some asphalt testing sites: acetic acid, n-butanol, sec-butanol, and methyl-isobutyl-ketone. All of these are breakdown products of solvents. In the absence of groundwater standards for these four contaminants,
NCDOT states that they use background concentrations as the threshold to determine compliance of their sites with 15A NCAC 02L .0202. They reported that the proposed standards for acetic acid, n-butanol, sec-butanol, and methyl-isobutyl-ketone are slightly higher than background concentrations; as such, compliance with the proposed standards may be achieved more readily.
Because the presence and detection of contaminants at each site is highly variable and unpredictable, NCDOT could not provide estimates of the number of sites that would benefit or the likelihood of benefit from the numerically higher standards. They did state, though, that any potential benefit would likely be negligible.
Further minimizing a potential benefit is the fact that a change to the standards for these four contaminants would only be realized if one of these contaminants were the main driver for remediation at a particular site. This type of data was not available for our analysis. For these reasons, we have not attempted to monetize the potential benefit.
In the absence of quantifiable data for asphalt testing sites, the general benefits summarized in Section 6.2.1 are applicable. If there are benefits to NCDOT in terms of cost savings, it would most likely be realized in the form of savings to their Highway Maintenance Fund, which funds groundwater remediation projects
among many other transportation-related projects. 6.2.11 Private wells None of the contaminants for which we are proposing standards are currently required to be analyzed for under Section 15A NCAC 18A .3800 Private Drinking
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Water Well Sampling. Nor do these rules require that well water comply with our
groundwater standards. The State does not use the groundwater standards to
regulate the water quality of private well water. The burden to monitor water quality of private well water is on the well owners. Information relating to the groundwater standards may be provided by NC DHHS to a well owner if there is a concern about possible contamination, but the well owner would not be required to
take action. For these reasons, the proposed groundwater standards should not
have any economic impact on private well owners. 6.3 Interim Maximum Allowable Concentrations (IMACs) If this analysis were to take into account existing IMACs, the estimated cost savings
would likely be considerably reduced for all but five contaminants. For the five contaminants
for which the proposed groundwater standard will be lower than the IMAC, there could be some remediation costs not accounted for in this analysis. Remediation costs would be limited to responsible parties for sites at which one of the following contaminants is a driver: acetochlor ESA, acetochlor OXA, 2,4-dinitrotoluene, n-butanol, and perfluorooctanoic acid (PFOA). For PFOA, potential costs would be offset by potential benefits of the higher PFOS
standard (see Section 6.2.3). For n-butanol, which was identified by NCDOT as a contaminant at asphalt testing sites, the potential costs from a lower cleanup goal would likely be negligible since it is a non-driver contaminant (see Section 6.2.10). For acetochlor ESA, acetochlor OXA, and 2,4-dinitrotoluene, the costs to site owners of a lower cleanup goal would be associated with increased monitoring frequency and duration and potential use of a
more expensive cleanup technology. State agencies could also incur opportunity costs from reduced staff capacity and funding resources that would have otherwise been reinvested at additional sites in need of cleanup. There are few sites at which these particular contaminants are the main drivers for cleanup, so the potential amount of costs realized is likely very low. 7. Summary The agency anticipates that if the groundwater standards are adopted as proposed, there would be an ongoing net benefit to regulated parties from having standards that are numerically-higher than
the regulatory baseline for 31 of the 47 contaminants (Table 3). For purposes of this analysis, the regulatory baseline is the Practical Quantitation Limit (PQL) and not the existing Interim Maximum Allowable Concentrations (IMACs). Because there are existing IMACs in place for all but two of the contaminants in Table 3, the bulk of the cost savings would be considered largely an ongoing benefit rather than a benefit that will begin at some point in the future.
For the other 16 contaminants (Table 2) included in this rulemaking, we concluded that the adoption of standards will neither increase nor decrease regulatory requirements because the PQL will remain the baseline. For this reason, the adoption of the 16 standards in Table 2 should have no quantifiable impact on regulated persons, at least for the foreseeable future.
Benefits associated with this rulemaking would be realized by parties regulated primarily under the agency’s UST, Hazardous Waste, Inactive Hazardous Waste, and Solid Waste Landfill programs. For most programs, we provided qualitative descriptions of the potential benefits,
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many of which could be generalized to all programs. We provided quantitative data when
available and made assumptions based on past data and trends when appropriate.
With the exception of the UST program, we did not attempt to monetize the potential benefits. This is because of the high degree of variability among sites in terms of which contaminants are present, which contaminants are the drivers for cleanup, the degree of contamination, the scale and
complexity of remediation required to meet groundwater standards, the protracted length of time
required to remediate groundwater, the age of some sites (i.e., lack of data). Together with the fact that we cannot reasonably predict future levels of groundwater contamination nor the pace at which cleanup and testing technologies will advance, we were hesitant to monetize future benefits associated with the groundwater standards as this would be overly speculative.

Unquantified benefits to regulated parties include reduced frequency of monitoring, reduced number of contaminants being tested, reduced number of groundwater wells being monitored (labor costs) and reduced cleanup time. Cost savings from completing groundwater remediation in a shorter period of time would largely be from spending less on operation and maintenance of the cleanup technology. Operation and maintenance costs can be substantial and would likely
make up the largest portion of cost savings realized from the proposed standards. The only quantified cost savings were related to the UST Program. It was estimated that over a five-year period, non-commercial UST owners, the State Commercial UST Trust Fund, and federal, state and local government agencies could realize a total maximum savings of $1.76M
(net present value). Unquantified benefits to State government include savings to staff time and resources for DEQ and NCDOT due to reduced administrative oversight.
Perhaps the largest beneficiary of this rulemaking would be the state taxpayer who would potentially benefit in terms of cost savings to the following state funds that provide full or partial funding for groundwater remediation projects:
• UST Commercial Trust Fund – funds groundwater remediation at commercial UST sites;
• State Highway Maintenance Fund – funds groundwater remediation at asphalt testing program;
• Solid Waste Disposal Tax Fund – funds groundwater remediation at inactive hazardous
waste landfills. Savings to these funds in the near term would allow remediation at more sites in the long term. This should result in improved compliance with the groundwater standards, which would result in
further protection of the groundwaters of the state as a resource and as a source of drinking water.
This benefit would be realized by the environment and by those citizens who consume private well water. If this analysis were to take into account existing IMACs, the estimated cost savings would likely
be considerably reduced for all but five contaminants for which the proposed standard is lower
than the IMAC. As summarized in Section 6.3, there could be some remediation costs associated with these contaminants which are not accounted for in this analysis. The costs to site owners of a
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lower cleanup goal would be associated with increased monitoring frequency and duration and
potential use of a more expensive cleanup technology. State agencies could also incur opportunity
costs from reduced staff capacity and funding resources that would have otherwise been reinvested at additional sites in need of cleanup. Remediation costs would be limited to sites at which one of the five contaminants is the driver for cleanup. Only one such site was identified during this analysis; for this site, the potential costs from a lower PFOA standard would be either fully or
partially offset by the potential savings from a higher PFOS standard.
The agency does not have sufficient data to reasonably predict whether the total quantified and unquantified impacts of the proposed rulemaking will meet or exceed the $1,000,000 threshold for substantial economic impact as defined in G.S. 150B-21.4. It is reasonable to expect, however,
that there will be a net direct benefit to regulated entities and state government and a zero to net-
positive indirect benefit for well water consumers and the environment. The amount of savings could not be determined because of the high degree of variability and unpredictability of contaminated sites and remediation methods.
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Appendix I References

1. For PQL values: NCDEQ Chemistry Laboratory “QA/QC Limits PQLs” https://files.nc.gov/ncdeq/Water+Quality/Chemistry+Lab/Operations/Quality+Assurance/NCDENR_DWR_WSS_LAB_PQLs.pdf
2. For identification of chemically-similar contaminant to 1,4-dibromobenzene: U.S. EPA Chemistry Dashboard https://comptox.epa.gov/dashboard/dsstoxdb/results?search=DTXSID4024012#similar-moleculesFor LCMRL values for Acetochlor ESA and OXA: U.S. EPA Document # EPA/600/R-05/053 “Method 535. Measurement of Chloroacetanilide and other Acetamide herbicide degradates in drinking water by solid phase extraction and liquid chromoatography/tandem mass spectrometry (LC/MS/MS)”
Version 1.1, April 2005, J.A. Shoemaker, M.V. Bassett 3. For the definition of Lowest Concentration Minimum Reporting Level: U.S. EPA Document # EPA 815-R-11-001 “Technical Basis for the Lowest Concentration Minimum Reporting Level (LCMRL) Calculator” December 2010. 4. For estimated number of private groundwater well users in North Carolina: https://epi.dph.ncdhhs.gov/oee/wellwater/figures.html 5. For determination of combined PFOS/PFOA groundwater standard: U.S. EPA drinking water health advisory https://www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos 6. For data on numbers of NCDWM Solid Waste permitted facilities:
https://deq.nc.gov/about/divisions/waste-management/sw/data/facility-lists 7. For determination of which contaminants are monitored at landfills: Appendix I and II referenced from NC
Solid Waste Section Environmental Monitoring List, Oct 15, 2018 https://edocs.deq.nc.gov/WasteManagement/0/edoc/1257181/SWS_EnviroMonitoring_Constituents_List.pdf
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TITLE 15A – DEPARTMENT OF ENVIRONMENTAL QUALITY
Notice is hereby given in accordance with G.S. 150B-21.2 that the Environmental Management Commission intends to amend the rule
cited as 15A NCAC 02L .0202.
Link to agency website pursuant to G.S. 150B-19.1(c): https://deq.nc.gov/news/events/public-notices-hearings
Proposed Effective Date: July 1, 2021
Public Hearing: Date: February 2, 2021 Time: 6:00 pm Location: In the abundance of caution, and to address protective measures to help prevent the spread of COVID-19, the NC Division
of Water Resources is holding an online public hearing that can be joined starting at 5:45 pm via WebEx link: https://ncdenrits.webex.com/ncdenrits/onstage/g.php?MTID=e5c544ae3124c6ca32f29b6ac45afb8ac,
WebEx password: jPeFQgQ3n85 WebEx phone number: 1-415-655-0003
WebEx access code: 178 659 9930
To register for the hearing and provide your preference regarding speaking at the hearing, please visit: https://forms.office.com/Pages/ResponsePage.aspx?id=3IF2etC5mkSFw-
zCbNftGRcM2xmuszROiks3JDQp2_RUNlJKWjlIRjlWWkhIVTRLMDFGM1gzSDRYMy4u
Or scan the following QR code with your phone:
Registration must be completed by 12:00 pm on February 2, 2021. If you have any problems registering online, please call 919-707-9011 by the registration deadline of 12:00 pm on February 2, 2021.
The Division of Water Resources highly recommends testing your computer's WebEx capabilities prior to the hearing at https://www.webex.com/test-meeting.html. For instructions about digital ways to join the public hearing, please refer to the WebEx Help Center online at https://help.webex.com/en-us/.
To comment during the hearing after your name is called as a registered speaker and/or after the hearing officer asks if any people wish to comment following the registered speakers: -If you join the hearing by phone, press *3 to “raise your hand,” speak once called upon to do so, and press *3 again to “lower yourhand.”-If you join the hearing online, press the hand icon to “raise your hand,” speak once called upon to do so, and press the hand iconagain to “lower your hand.”-The Hearing Officer may limit the length of time that you may speak, so that all those who wish to speak may do so.
Reason for Proposed Action: Groundwater Quality Standards for the protection of groundwaters of the state are established by 15A
NCAC 02L .0202. They are the maximum allowable concentrations resulting from any discharge of contaminants to the land or waters of the state, which may be tolerated without creating a threat to human health or which would otherwise render the groundwater
unsuitable for its intended best usage as an existing or potential source of drinking water supply for humans. Every three years the State is required by 15A NCAC 02L .0202(g) to review its groundwater water quality standards and interim maximum allowable
concentrations to determine if changes are needed and, if necessary, to make those changes. Revision of these standards is needed to ensure that they contain the most recent health and toxicological information. The last review focused on the interim maximum allowable
concentrations established under 15A NCAC 02L .0202(c).
Proposed changes to 15A NCAC 02L .0202 include: •The adoption of a groundwater quality standard for 44 substances with established interim maximum allowable concentrations,
some with revisions,•the addition of a groundwater quality standard for three substances (2,6-dinitrotoluene, strontium, and total PFOA and PFOS)
without established interim maximum allowable concentrations,•the organization of the groundwater standards into a table,
•the addition of Chemical Abstracts Service Registry Numbers (CASRNs) for the groundwater standards,•the removal of synonyms,
•a change in some units of measure to parts per billion (µg/L), when appropriate,•the addition of rule text to add a notification process for the establishment of an interim maximum allowable concentration,
and•the addition of rule text to clarify the triennial review process.C1
Attachment C: Public Hearing Announcement
Comments may be submitted to: Bridget Shelton, NC DEQ-DWR Planning Section, 1611 Mail Service Center, Raleigh, NC 27699-
1611; email [e-mail] Comment period ends: March 16, 2021 Procedure for Subjecting a Proposed Rule to Legislative Review: If an objection is not resolved prior to the adoption of the rule, a person may also submit written objections to the Rules Review Commission after the adoption of the Rule. If the Rules Review Commission receives written and signed objections after the adoption of the Rule in accordance with G.S. 150B-21.3(b2) from 10 or more persons clearly requesting review by the legislature and the Rules Review Commission approves the rule, the rule will become effective as provided in G.S. 150B-21.3(b1). The Commission will receive written objections until 5:00 p.m. on the day following the day the Commission approves the rule. The Commission will receive those objections by mail, delivery service, hand delivery, or
facsimile transmission. If you have any further questions concerning the submission of objections to the Commission, please call a Commission staff attorney at 919-431-3000. Fiscal impact. Does any rule or combination of rules in this notice create an economic impact? Check all that apply. State funds affected Local funds affected Substantial economic impact (>= $1,000,000) Approved by OSBM No fiscal note required CHAPTER 02 - ENVIRONMENTAL MANAGEMENT SUBCHAPTER 02L - GROUNDWATER CLASSIFICATION AND STANDARDS SECTION .0200 - CLASSIFICATIONS AND GROUNDWATER QUALITY STANDARDS 15A NCAC 02L .0202 GROUNDWATER QUALITY STANDARDS (a) The groundwater quality standards for the protection of the groundwaters of the state are those specified in this Rule. They are the
maximum allowable concentrations resulting from any discharge of contaminants to the land or waters of the state, which may be tolerated without creating a threat to human health or which would otherwise render the groundwater unsuitable for its intended best usage. (b) The groundwater quality standards for contaminants specified in Paragraphs (h) and (i) of this Rule are as listed, except that:
(1) Where the standard for a substance is less than the practical quantitation limit, the detection of that substance at or above the practical quantitation limit constitutes a violation of the standard.
(2) Where two or more substances exist in combination, the Director shall consider the effects of chemical interactions as determined by the Division of Public Health and may establish maximum concentrations at values less than those established in accordance with Paragraphs (c), (h), or (i) of this Rule. In the absence of information to the contrary, in accordance with Paragraph (d) of this Rule, the carcinogenic risks associated with carcinogens present shall be
considered additive and the toxic effects associated with non-carcinogens present shall also be considered additive. (3) Where naturally occurring substances exceed the established standard, the standard shall be the naturally occurring concentration as determined by the Director. (4) Where the groundwater standard for a substance is greater than the Maximum Contaminant Level (MCL), the Director
shall apply the MCL as the groundwater standard at any private drinking water well or public water system well that may be impacted. (c) Except for tracers used in concentrations which have been determined by the Division of Public Health to be protective of human health, and the use of which has been permitted by the Division, substances which are not naturally occurring and for which no standard is specified shall not be permitted in concentrations at or above the practical quantitation limit in Class GA or Class GSA groundwaters. Any person may petition the Director of the Division of Water Resources to establish an interim maximum allowable concentration Interim Maximum Allowable Concentration (IMAC) for a substance for which a standard has not been established under this Rule. The petitioner shall submit relevant toxicological and epidemiological data, study results, and calculations necessary to establish a standard in accordance with Paragraph Paragraphs (d) and (e) of this Rule. Within three months after the establishment of an interim maximum allowable concentration for a substance by the Director, the Director shall initiate action to consider adoption of a standard for that substance. If the information submitted is not in accordance with Paragraphs (d) and (e) of this Rule, the Director of the Division of Water Resources shall request additional information from the petitioner. If the petitioner does not provide the additional information necessary to be in accordance with Paragraphs (d) and (e) of this Rule, the Director of the Division of Water Resources shall deny the petition. At least 30 days prior to establishing an IMAC for any substance, the Division of Water Resources shall provide public notice that an IMAC has been requested. The public notice shall include the petition requesting the establishment of the IMAC for a substance, the level of the proposed IMAC, and the basis upon which the Division of Water Resources has relied in development of the proposed IMAC. This notice shall be published in the North Carolina Register and posted on the Division of Water Resources's website: https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-standards/groundwater-imacs. If the Director of the Division of Water Resources establishes an IMAC, the IMAC shall be posted on the Division of Water Resources's website and the Commission shall be notified in writing within 30 calendar days that a new IMAC has been established.
C2
(d) Except as provided in Paragraph (f) of this Rule, groundwater quality standards for substances in Class GA and Class GSA groundwaters are established as the least of: (1) Systemic threshold concentration calculated as follows: [Reference Dose (mg/kg/day) x 70 kg (adult body weight) x Relative Source Contribution (.10 (0.10 for inorganics; .20 0.20 for organics)] / [2 liters/day (avg. water consumption)]; (2) Concentration which corresponds to an incremental lifetime cancer risk of 1x10-6;
(3) Taste threshold limit value; (4) Odor threshold limit value; (5) Maximum contaminant level; or (6) National secondary drinking water standard. (e) The following references, in order of preference, shall be used in establishing concentrations of substances which correspond to levels described in Paragraph (d) of this Rule.
(1) Integrated Risk Information System (U.S. EPA). (2) Health Advisories (U.S. EPA Office of Drinking Water). (3) Other health risk assessment data published by the U.S. EPA. (4) Other relevant, published health risk assessment data, and scientifically valid peer-reviewed published toxicological
data. (f) The Commission may establish groundwater standards less stringent than existing maximum contaminant levels or national
secondary drinking water standards if it finds, after public notice and opportunity for hearing, that: (1) more recent data published in the EPA health references listed in Paragraph (e) of this Rule results in a standard which is protective of public health, taste threshold, or odor threshold; (2) the standard will not endanger the public health and safety, including health and environmental effects from exposure
to groundwater contaminants; and (3) compliance with a standard based on the maximum contaminant level or national secondary drinking water standard
would produce serious hardship without equal or greater public benefit. (g) Groundwater quality standards specified in Paragraphs (h) and (i) of this Rule and interim maximum allowable concentrations IMACs established pursuant to Paragraph (c) of this Rule shall be reviewed by the Director Division of Water Resources on a triennial basis. basis and reported to the Commission. The Director of the Division of Water Resources shall consider the following actions during the review of an established IMAC: (1) recommend codifying the IMAC as a groundwater quality standard under this Rule;
(2) update the IMAC value based on data published or rescinded subsequent to the previous review; (3) remove the IMAC based on data published or rescinded subsequent to the previous review; or (4) retain the IMAC at the current value; Any IMAC recommended under Subparagraph (g)(1) of this Rule that the Commission does not codify shall remain an established IMAC and be reviewed during the next triennial review. Appropriate modifications Modifications to established standards shall be made made, through rulemaking, in accordance with the procedure procedures prescribed in Paragraph Paragraphs (d) and (e) of this Rule
where modifications are considered appropriate based on data published subsequent to the previous review. (h) Class GA Standards. Unless otherwise indicated, the standard refers to the total concentration in micrograms per liter (µg/L) of any constituent in a dissolved, colloidal or particulate form which is mobile in groundwater. This does not apply to sediment or other particulate matter which is preserved in a groundwater sample as a result of well construction or sampling procedures. The Class GA standards are: (1) Acenaphthene: 80; (2) Acenaphthylene: 200; (3) Acetone: 6 mg/L; (4) Acrylamide: 0.008; (5) Anthracene: 2 mg/L; (6) Arsenic: 10; (7) Atrazine and chlorotriazine metabolites: 3; (8) Barium: 700; (9) Benzene: 1; (10) Benzo(a)anthracene (benz(a)anthracene): 0.05; (11) Benzo(b)fluoranthene: 0.05; (12) Benzo(k)fluoranthene: 0.5; (13) Benzoic acid: 30 mg/L; (14) Benzo(g,h,i,)perylene: 200; (15) Benzo(a)pyrene: 0.005; (16) Bis(chloroethyl)ether: 0.03; (17) Bis(2-ethylhexyl) phthalate (di(2-ethylhexyl) phthalate): 3; (18) Boron: 700; (19) Bromodichloromethane: 0.6; (20) Bromoform (tribromomethane): 4; (21) n-Butylbenzene: 70; (22) sec-Butylbenzene: 70; (23) tert-Butylbenzene: 70; (24) Butylbenzyl phthalate: 1 mg/L; C3
(25) Cadmium: 2; (26) Caprolactam: 4 mg/L; (27) Carbofuran: 40; (28) Carbon disulfide: 700; (29) Carbon tetrachloride: 0.3; (30) Chlordane: 0.1;
(31) Chloride: 250 mg/L; (32) Chlorobenzene: 50; (33) Chloroethane: 3,000; (34) Chloroform (trichloromethane): 70; (35) Chloromethane (methyl chloride): 3; (36) 2-Chlorophenol: 0.4;
(37) 2-Chlorotoluene (o-chlorotoluene): 100; (38) Chromium: 10; (39) Chrysene: 5; (40) Coliform organisms (total): 1 per 100 mL; (41) Color: 15 color units; (42) Copper: 1 mg/L;
(43) Cyanide (free cyanide): 70; (44) 2, 4-D (2,4-dichlorophenoxy acetic acid): 70; (45) DDD: 0.1; (46) DDT: 0.1; (47) Dibenz(a,h)anthracene: 0.005; (48) Dibromochloromethane: 0.4;
(49) 1,2-Dibromo-3-chloropropane: 0.04; (50) Dibutyl (or di-n-butyl) phthalate: 700; (51) 1,2-Dichlorobenzene (orthodichlorobenzene): 20; (52) 1,3-Dichlorobenzene (metadichlorobenzene): 200; (53) 1,4-Dichlorobenzene (paradichlorobenzene): 6; (54) Dichlorodifluoromethane (Freon-12; Halon): 1 mg/L;
(55) 1,1-Dichloroethane: 6; (56) 1,2-Dichloroethane (ethylene dichloride): 0.4; (57) 1,2-Dichloroethene (cis): 70; (58) 1,2-Dichloroethene (trans): 100; (59) 1,1-Dichloroethylene (vinylidene chloride): 350; (60) 1,2-Dichloropropane: 0.6;
(61) 1,3-Dichloropropene (cis and trans isomers): 0.4; (62) Dieldrin: 0.002; (63) Diethylphthalate: 6 mg/L; (64) 2,4-Dimethylphenol (m-xylenol): 100; (65) Di-n-octyl phthalate: 100; (66) 1,4-Dioxane (p-dioxane): 3; (67) Dioxin (2,3,7,8-TCDD): 0.0002 ng/L; (68) 1,1– Diphenyl (1,1,-biphenyl): 400; (69) Dissolved solids (total): 500 mg/L; (70) Disulfoton: 0.3; (71) Diundecyl phthalate (Santicizer 711): 100; (72) Endosulfan: 40; (73) Endrin, total (includes endrin, endrin aldehyde and endrin ketone): 2; (74) Epichlorohydrin: 4; (75) Ethyl acetate: 3 mg/L; (76) Ethylbenzene: 600; (77) Ethylene dibromide (1,2-dibromoethane): 0.02; (78) Ethylene glycol: 10 mg/L; (79) Fluoranthene: 300; (80) Fluorene: 300; (81) Fluoride: 2 mg/L; (82) Foaming agents: 500; (83) Formaldehyde: 600; (84) Gross alpha (adjusted) particle activity (excluding radium-226 and uranium): 15 pCi/L; (85) Heptachlor: 0.008; (86) Heptachlor epoxide: 0.004; (87) Heptane: 400; (88) Hexachlorobenzene (perchlorobenzene): 0.02; (89) Hexachlorobutadiene: 0.4; C4
(90) Hexachlorocyclohexane isomers (technical grade): 0.02; (91) n-Hexane: 400; (92) Indeno(1,2,3-cd)pyrene: 0.05; (93) Iron: 300; (94) Isophorone: 40; (95) Isopropylbenzene: 70;
(96) Isopropyl ether: 70; (97) Lead: 15; (98) Lindane (gamma hexachlorocyclohexane): 0.03; (99) Manganese: 50; (100) Mercury: 1; (101) Methanol: 4 mg/L;
(102) Methoxychlor: 40; (103) Methylene chloride (dichloromethane): 5; (104) Methyl ethyl ketone (2-butanone): 4 mg/L; (105) 2-Methylnaphthalene: 30; (106) 3-Methylphenol (m-cresol): 400; (107) 4-Methylphenol (p-cresol): 40;
(108) Methyl tert-butyl ether (MTBE): 20; (109) Naphthalene: 6; (110) Nickel: 100; (111) Nitrate (as N): 10 mg/L; (112) Nitrite (as N): 1 mg/L; (113) N-nitrosodimethylamine: 0.0007;
(114) Oxamyl: 200; (115) Pentachlorophenol: 0.3; (116) Petroleum aliphatic carbon fraction class (C5 - C8): 400; (117) Petroleum aliphatic carbon fraction class (C9 - C18): 700; (118) Petroleum aliphatic carbon fraction class (C19 - C36): 10 mg/L; (119) Petroleum aromatics carbon fraction class (C9 - C22): 200;
(120) pH: 6.5 - 8.5; (121) Phenanthrene: 200; (122) Phenol: 30; (123) Phorate: 1; (124) n-Propylbenzene: 70; (125) Pyrene: 200;
(126) Selenium: 20; (127) Silver: 20; (128) Simazine: 4; (129) Styrene: 70; (130) Sulfate: 250 mg/L; (131) 1,1,2,2-Tetrachloroethane: 0.2; (132) Tetrachloroethylene (perchloroethylene; PCE): 0.7; (133) 2,3,4,6-Tetrachlorophenol: 200; (134) Toluene: 600; (135) Toxaphene: 0.03; (136) 2,4,5-TP (Silvex): 50; (137) 1,2,4-Trichlorobenzene: 70; (138) 1,1,1-Trichloroethane: 200; (139) Trichloroethylene (TCE): 3; (140) Trichlorofluoromethane: 2 mg/L; (141) 1,2,3-Trichloropropane: 0.005; (142) 1,2,4-Trimethylbenzene: 400; (143) 1,3,5-Trimethylbenzene: 400; (144) 1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113): 200 mg/L; (145) Vinyl chloride: 0.03; (146) Xylenes (o-, m-, and p-): 500; and (147) Zinc: 1 mg/L. Substance Chemical Abstracts Service (CAS) Registry Number
Standard (µg/L)
Acenaphthene 83-32-9 80
Acenaphthylene 208-96-8 200
Acetic acid 64-19-7 5,000 C5
Acetochlor 34256-82-1 100
Acetochlor ESA 187022-11-3 500 Acetochlor OXA 184992-44-4 500
Acetone 67-64-1 6,000
Acetophenone 98-86-2 700
Acrolein 107-02-8 4 Acrylamide 79-06-1 0.008
Alachlor 15972-60-8 2
Aldrin 309-00-2 0.002
Anthracene 120-12-7 2,000
Antimony 7440-36-0 1
Arsenic 7440-38-2 10
Atrazine and chlorotriazine metabolites 1912-24-9 3
Barium 7440-39-3 700 Benzene 71-43-2 1
Benzo(a)anthracene 56-55-3 0.05
Benzo(a)pyrene 50-32-8 0.005
Benzo(b)fluoranthene 205-99-2 0.05 Benzo(g,h,i)perylene 191-24-2 200
Benzo(k)fluoranthene 207-08-9 0.5
Benzoic acid 65-85-0 30,000
Benzyl alcohol 100-51-6 700
Beryllium 7440-41-7 4
Bis(chloroethyl)ether 111-44-4 0.03
Bis(2-ethylhexyl) phthalate 117-81-7 3
Boron 7440-42-8 700 Bromodichloromethane 75-27-4 0.6
Bromoform 75-25-2 4
Bromomethane 74-839-9 10
n-Butanol 71-36-3 590 sec-Butanol 78-92-2 10,000
n-Butylbenzene 104-51-8 70
sec-Butylbenzene 135-98-8 70
tert-Butylbenzene 98-06-6 70
Butylbenzyl phthalate 85-68-7 1,000
Cadmium 7440-43-9 2
Caprolactam 105-60-2 4,000
Carbofuran 1563-66-2 40 Carbon disulfide 75-15-0 700
Carbon tetrachloride 56-23-5 0.3
Chlordane 12789-03-6 0.1
Chloride 16887-00-6 250,000 Chlorobenzene 108-90-7 50
Chloroethane 75-00-3 3,000
Chloroform 67-66-3 70
Chloromethane 74-87-3 3
2-Chlorophenol 95-57-8 0.4
2-Chlorotoluene 95-49-8 100
4-Chlorotoluene 106-43-4 24
Chromium 7440-47-3 10 Chrysene 218-01-9 5
Cobalt 7440-48-4 1
Coliform organisms (total) No CAS Registry Number 1 per 100 mL
Color No CAS Registry Number 15 color units Copper 7440-50-8 1,000
Cyanide (free cyanide) 57-12-5 70
2,4-D (2,4-dichlorophenoxy acetic acid) 94-75-7 70
Dalapon 75-99-0 200
DDD 72-54-8 0.1
DDE 72-55-9 0.1
DDT 50-29-3 0.1 C6
Dibenz(a,h)anthracene 53-70-3 0.005
1,4-Dibromobenzene 106-37-06 70 Dibromochloromethane 124-48-1 0.4
1,2-Dibromo-3-chloropropane 96-12-8 0.04
Dibutyl phthalate 84-74-2 700
Dichloroacetic acid 79-43-6 0.7 1,2-Dichlorobenzene 95-50-1 20
1,3-Dichlorobenzene 541-73-1 200
1,4-Dichlorobenzene 106-46-7 6
Dichlorodifluoromethane 75-71-8 1,000
1,1-Dichloroethane 75-34-3 6
1,2-Dichloroethane 107-06-2 0.4
1,2-Dichloroethene (cis) 156-59-2 70
1,2-Dichloroethene (trans) 156-60-5 100 1,1-Dichloroethylene 75-35-4 350
2,4-Dichlorophenol 120-83-2 0.98
1,2-Dichloropropane 78-87-5 0.6
1,3-Dichloropropene (cis and trans isomers) 542-75-6 0.4 Dieldrin 60-57-1 0.002
Diethylphthalate 84-66-2 6,000
2,4-Dimethylphenol 105-67-9 100
2,4-Dinitrotoluene 121-14-2 0.05
2,6-Dinitrotoluene 606-20-2 0.05
Di-n-octyl phthalate 117-84-0 100
Dinoseb 88-85-7 7
1,4-Dioxane 123-91-1 3 Dioxin (2,3,7,8-TCDD) 1746-01-6 0.0002 ng/L
1,1-Diphenyl 92-52-4 400
Diphenyl ether 101-84-8 180
Diquat 85-00-7 20 Dissolved solids (total) No CAS Registry Number 500,000
Disulfoton 298-04-4 0.3
Diundecyl phthalate (Santicizer 711) 3648-20-2 100
Endosulfan 115-29-7 40
Endosulfan sulfate 115-29-7 40
Endothall 145-73-3 100
Endrin, total (includes endrin, endrin aldehyde, and
endrin ketone)
72-20-8 2
Epichlorohydrin 106-89-8 4
Ethyl acetate 141-78-6 3,000
Ethylbenzene 100-41-4 600 Ethylene dibromide 106-93-4 0.02
Ethylene glycol 107-21-1 10,000
Fluoranthene 206-44-0 300
Fluorene 86-73-7 300 Fluoride 16984-48-8 2,000
Foaming agents No CAS Registry Number 500
Formaldehyde 50-00-0 600
Gross alpha (adjusted) particle activity (excludes
radium-226 and uranium)
12587-46-1 15 pCi/L
Heptachlor 76-44-8 0.008
Heptachlor epoxide 1024-57-3 0.004
Heptane 142-82-5 400
Hexachlorobenzene 118-74-1 0.02
Hexachlorobutadiene 87-68-3 0.4
Hexachlorocyclohexane isomers (technical grade) 608-73-1 0.02 alpha-Hexachlorocyclohexane 319-84-6 0.006
beta-Hexachlorocyclohexane 319-85-7 0.02
gamma-Hexachlorocyclohexane (Lindane) 58-89-9 0.03
n-Hexane 110-54-3 400 Indeno(1,2,3-cd)pyrene 193-39-5 0.05 C7
Iron 7439-89-6 300
Isophorone 78-59-1 40 Isopropyl ether 108-20-3 70
Isopropylbenzene 98-82-8 70
4-Isopropyltoluene 99-87-6 25
Lead 7439-92-1 15 Manganese 7439-96-5 50
Mercury 7439-97-6 1
Methanol 67-56-1 4,000
Methoxychlor 72-43-5 40
Methylene chloride 75-09-2 5
Methyl butyl ketone 591-78-6 40
Methyl ethyl ketone 78-93-3 4,000
Methyl isobutyl ketone 108-10-1 100 Methyl methacrylate 80-62-6 25
1-Methylnapthalene 90-12-0 1
2-Methylnaphthalene 91-57-6 30
2-Methylphenol 95-48-7 400 3-Methylphenol 108-39-4 400
4-Methylphenol 106-44-5 40
Methyl tert-butyl ether (MTBE) 1634-04-4 20
Naphthalene 91-20-3 6
Nickel 7440-02-0 100
Nitrate (as N) 14797-55-8 10,000
Nitrite (as N) 14797-65-0 1,000
N-nitrosodimethylamine 62-75-9 0.0007 Oxamyl 23135-22-0 200
Pentachlorophenol 608-93-5 0.3
Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA), total 1763-23-1 (PFOS); 335-67-1 (PFOA) 0.07
Petroleum aliphatic carbon fraction class (C5 – C8) No CAS Registry Number 400
Petroleum aliphatic carbon fraction class (C9 – C18) No CAS Registry Number 700
Petroleum aliphatic carbon fraction class (C19 – C36) No CAS Registry Number 10,000 Petroleum aromatics carbon fraction class (C9 – C22) No CAS Registry Number 200
pH No CAS Registry Number 6.5 - 8.5 (no unit)
Phenanthrene 85-01-8 200
Phenol 108-95-2 30
Phorate 298-02-2 1
n-Propylbenzene 103-65-1 70
Propylene glycol 57-55-6 100,000
Pyrene 129-00-0 200 Selenium 7782-49-2 20
Silver 7440-22-4 20
Simazine 122-34-9 4
Strontium 7440-24-6 2,000 Styrene 100-42-5 70
Sulfate 14808-79-8 250,000
1,2,4,5-Tetrachlorobenzene 95-94-3 2
1,1,2,2-Tetrachloroethane 79-34-5 0.2
1,1,1,2-Tetrachloroethane 630-20-6 1
Tetrachloroethylene (PCE) 127-18-4 0.7
2,3,4,6-Tetrachlorophenol 58-90-2 200
Thallium 7440-28-0 2 Tin (inorganic forms) 7440-31-5 2,000
Toluene 108-88-3 600
Toxaphene 8001-35-2 0.03
2,4,5-TP (Silvex) 93-72-1 50 1,2,4-Trichlorobenzene 120-82-1 70
1,1,1-Trichloroethane 71-55-6 200
1,1,2-Trichloroethane 79-00-5 0.6
Trichloroethylene (TCE) 79-01-6 3 C8
Trichlorofluoromethane 75-69-4 2,000
2,4,5-Trichlorophenol 95-95-4 63 2,4,6-Trichlorophenol 88-06-2 4
1,2,3-Trichloropropane 96-18-4 0.005
1,2,4-Trimethylbenzene 95-63-6 400
1,3,5-Trimethylbenzene 108-67-8 400 Vanadium 7440-62-2 7
1,1,2-Trichloro-1,2,2-trifluoroethane 76-13-1 200,000
Vinyl chloride 75-01-4 0.03
Xylenes 1330-20-7 500
Zinc 7440-66-6 1,000
(i) Class GSA Standards. The standards for this class are the same as those for Class GA except as follows: (1) chloride: allowable increase not to exceed 100 percent of the natural quality concentration; and (2) dissolved solids (total): 1000 mg/L. 1,000,000 µg/L. (j) Class GC Standards. (1) The concentrations of substances that, at the time of classification, exceed the standards applicable to Class GA or
GSA groundwaters shall not be caused to increase, nor shall the concentrations of other substances be caused to exceed the GA or GSA standards as a result of further disposal of contaminants to or beneath the surface of the land within the boundary of the area classified GC. (2) The concentrations of substances that, at the time of classification, exceed the standards applicable to GA or GSA groundwaters shall not be caused to migrate as a result of activities within the boundary of the GC classification, so as to violate the groundwater or surface water quality standards in adjoining waters of a different class.
(3) Concentrations of specific substances, that exceed the established standard at the time of classification, are listed in Section .0300 of this Subchapter. History Note: Authority G.S. 143-214.1; 143B-282(a)(2);
Eff. June 10, 1979; Amended Eff. November 1, 1994; October 1, 1993; September 1, 1992; August 1, 1989;
Temporary Amendment Eff. June 30, 2002; Amended Eff. August 1, 2002;
Temporary Amendment Expired February 9, 2003; Amended Eff. April 1, 2013; January 1, 2010; April 1, 2005;
Pursuant to G.S. 150B-21.3A, rule is necessary without substantive public interest Eff. March 6, 2018. Amended Eff. July 1, 2021.

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Page 1 of 3
ONLINE PUBLIC HEARING: Groundwater Quality Standards
February 2, 2021, 6:00 p.m. Hearing Officer: Yvonne Bailey
Good evening. It is now 6:00 p.m. and this public hearing is officially called to order.
My name is Yvonne Bailey and I am a member of the Environmental Management Commission. I have been designated as the hearing officer for the 15A NCAC 02L .0202 Groundwater Quality Standards rulemaking effort.
If you are having technical difficulties with WebEx, you can use the chat feature in WebEx to ask questions or
seek assistance. You can also view the public announcement for this hearing, which is a link on the Department of Environmental Quality’s Public Notices and Hearings website, for instructions on various ways to connect to WebEx and for the WebEx phone number and access code for this hearing.
This hearing is being held under the authority of North Carolina General Statutes, Chapter 150B-21.2. In
accordance with the General Statutes, a public notice of this hearing was published in the January 15, 2021 edition of the North Carolina Register. Notice to the public was also provided through the Division’s website and a press release was issued by the Division of Water Resources on January 15, 2021.
The purpose of today’s Hearing is to obtain public comment on the proposed amendments to the regulations
governing groundwater quality standards and its fiscal analysis. In a moment, Bridget Shelton, a Division of Water Resources staff member, will review this proposal for you. There is additional information available on the Department of Environmental Quality’s Public Notices and Hearings webpage that describes the proposal.
A written record of this hearing will be prepared that will include all the relevant comments, questions, and
discussions. For this reason, the hearing is being recorded. Written comments received by March 16, 2021 will also be included in the record.
Based on the public comments received by March 16th and input and review of the comments by myself and the
Division of Water Resources staff, I will make a recommendation to the Environmental Management Commission after the record is complete. In making the final decision, the Environmental Management Commission will consider the written record, the recommendations of Division staff, the recommendations of the Hearing Officer, and any concerns of other commission members.
The recommendation for the proposed rule may be to adopt it as proposed or to adopt a modified version of the proposal. The Environmental Management Commission may adopt the recommendation, modify it, or reject it. If the Commission wishes to adopt a rule that differs substantially from what has been published in the North Carolina Register and proposed this evening, it must first publish the text of the proposed different rule and
accept comments on the new text.
D1
Attachment D: Hearing Officer's Remarks
Page 2 of 3
Now, Bridget Shelton will present a brief overview of the proposed rule changes. After Bridget’s presentation, comments from the audience will be allowed. <Bridget’s presentation> Thank you, Bridget.
The Environmental Management Commission wants to hear your comments on the proposed rule. All interested and potentially affected persons or parties are encouraged to make their opinion known to the Commission, whether in favor of or opposed to any or all provisions of the proposed rule. Please know that your comments are important and will enable the Commission to act in the best interest of the public.
Please also remember that the intent of this hearing is to solicit your comments on the proposed amendments to the groundwater quality standards and associated fiscal analysis. It is important that you keep your comments concise and relevant to the proposal and fiscal analysis. It is critical that we have time to get all your comments on the proposal and its fiscal analysis and will hear them first. Then if you have other comments that you believe should be voiced to the staff or the Hearing Officer, we will try to give additional time at the end of the
hearing for those comments, or you can contact staff after the hearing with those comments. We will now accept comments on the proposed rule from the audience. I will call on speakers in the order that you registered for this hearing. If you have joined the hearing by phone, press *3 to “raise your hand,” speak once called upon to do so, and press *3 again to “lower your hand.” If you have joined the hearing online, press
the hand icon to “raise your hand,” speak once called upon to do so, and press the hand icon again to “lower your hand.” The WebEx Host will unmute each speaker when it is his or her turn to speak. I will also state the name of the next speaker in the queue so that individual can be prepared when his or her name is called to speak. Please do
not start speaking until the Webex Host has indicated that your microphone has been unmuted. If I call your name, but cannot hear you after you have been unmuted, please check to see if you are muted on the Webex screen on your computer. If you are having audio issues, try a different method of audio connection within Webex or use the “Call Me” feature to have Webex call your personal telephone line. If I still cannot
hear you, I will proceed to the next registered speaker, but will call your name again at the end of the hearing. When your name is called, please clearly and slowly state your name and any affiliation with an organization you may be representing. If you have written copies of your comments, we would appreciate receiving a copy of them. We may question speakers, if necessary, to clarify or learn more about matters as they arise. After all
the registered speakers have had an opportunity to comment, any registered speaker who could not previously be heard will be called upon to speak. In addition, anyone who did not register to speak or desires additional time to speak will have the opportunity to comment. Please remember that Division of Water Resources staff can be contacted after the hearing to address any additional questions or comments that you may have.
Because a large number of people have requested to speak, it will be necessary to impose a time limit of 4 minutes. A member of the Division of Water Resources staff will be timing the comments and will state when you have one minute remaining to speak. We appreciate your cooperation with this time limit so that everyone who wishes to speak is able to do so.
I will now call on the first speaker. (call names of speakers in the order that they registered) <if there is time> Are there any additional comments? If there are no more comments, I declare the hearing closed.
<if there isn't time for additional comments> I declare this hearing closed.
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Page 3 of 3
The hearing record will remain open until March 16, 2021. That means that anytime between today and close of
business on March 16, 2021, anyone can submit further comments on the proposed rules in writing to Ms.
Shelton. Written comments received by US Mail or by e-mail during this time period will be made a part of the public record. (the public notice announcement and the last slide of the presentation will have both addresses for you to reference).
After the comment period has ended on March 16th, Division of Water Resources staff and I will review the
comments and prepare a report of proceedings including all the comments; then we will make a recommendation to the Environmental Management Commission. The Commission will make a decision regarding the proposal after consideration of the report of proceedings and our recommendation. As I noted earlier, the Commission may not make substantial changes in the final rules without re-notice and rehearing. If
the Commission adopts the proposed rules, then the expected effective date for the rules would be July 1, 2021.
We thank everyone for attending this online hearing and offering your comments.
D3
Public Hearing on Proposed Rule Amendments and Regulatory Impact
Analysis for 15A NCAC 02L .0202 Groundwater Quality Standards
February 2, 2021
NC Groundwater Quality Standards
Federal Requirement No
North Carolina Rule 15A NCAC 02L .0202
Population Human Adults
Target use Ingestion
Household use
Standard endpoints
Noncancer
Cancer
Aqueous taste and odor
2
North Carolina Groundwater Quality Standards
• Maximum allowable concentrations which may be
tolerated without creating a threat to human health
or which would otherwise render the groundwaterunsuitable for its intended best usage
• Best Usage: existing or potential source of drinking
water supply for humans
• Protect groundwaters of the state as a resource for
human consumption
• Implemented in various programs including site
clean-ups, risk assessments, and health evaluations
1
2
E1
Attachment E:
Public Hearing Division of Water Resources Staff Presentation
• When a groundwater standard has not been established under the
rule for a substance, any person may petition the Director to establish
an interim maximum allowable concentration (IMAC).
• The petitioner must submit relevant toxicological and epidemiological
data, study results, and calculations necessary to establish an IMAC
in accordance with NCAC 02L .0202 (d).
• DWR staff evaluate the submitted data and determine the appropriate
protective level for the chemical of concern following procedures
outlined in 15A NCAC 02L .0202.
3
Interim Maximum Allowable Concentrations (IMACs)
15A NCAC 02L .0202 (c)
Periodic Review of IMACs
• 15A NCAC 02L .0202 (g): Groundwater quality standards and interim
maximum allowable concentrations shall be reviewed on a triennial basis.
• DWR staff review the toxicological research and literature in accordance
with 15A NCAC 02L .0202 to account for new information, new data, or
reexaminations of existing data.
• DWR staff consider appropriate modifications and prepare reports which are
reviewed by internal staff
• DWR submit prepared reports to DWM and DHHS toxicology staff for review
and/or further discussion and comment
4
3
4
E2
• Incorporate 44 existing IMACs
• Revisions for some compounds based on new data,
recalculations, and reexamination of existing data
• Add a Groundwater Quality Standard for the following compounds:
• 2,6-Dinitrotoluene, Strontium, PFOA and PFOS (total)
5
Proposed Amendments to 15A NCAC 02L .0202
Compounds with Proposed Revised Values
• Revisions for some compounds based on new data, recalculations, andreexamination of existing data:
• Acetochlor ESA
• Acetochlor OXA
• Alachlor
• n-Butanol
• 2,4-Dinitrotoluene
• Diphenyl ether
• PFOA and PFOS
• Thallium
• Vanadium
6
5
6
E3
• Add Chemical Abstracts Service (CAS) Registry Numbers for
existing groundwater standards and proposed incorporated IMACs
• Updates for clarification and ease of use:
• Organize standards into table, remove synonyms, report in
uniform units
7
Proposed Amendments to 15A NCAC 02L .0202 continued
Proposed rule text revisions:
• 15A NCAC 02L .0202 (c): rule text revisions to add IMAC notification process
• 15A NCAC 02L .0202 (g): rule text revisions to clarify triennial review process
8
Proposed Amendments to 15A NCAC 02L .0202 continued
7
8
E4
Proposed rule text revisions to 15A NCAC 02L .0202 (c)
9
(c) Except for tracers used in concentrations which have been determined by the Division of Public Health to
be protective of human health, and the use of which has been permitted by the Division, substances which
are not naturally occurring and for which no standard is specified shall not be permitted in concentrations at
or above the practical quantitation limit in Class GA or Class GSA groundwaters. Any person may petition
the Director of the Division of Water Resources to establish an interim maximum allowable concentration
Interim Maximum Allowable Concentration (IMAC) for a substance for which a standard has not been
established under this Rule. The petitioner shall submit relevant toxicological and epidemiological data,
study results, and calculations necessary to establish a standard in accordance with Paragraphs (d) and (e) of
this Rule. Within three months after the establishment of an interim maximum allowable concentration for a
substance by the Director, the Director shall initiate action to consider adoption of a standard for that
substance.If the information submitted is not in accordance with Paragraphs (d) and (e) of this Rule, the
Director of the Division of Water Resources shall request additional information from the petitioner. If the
petitioner does not provide the additional information necessary to be in accordance with Paragraphs (d) and
(e) of this rule, the Director of the Division of Water Resources shall deny the petition.
Proposed rule text revisions to 15A NCAC 02L .0202 (c) continued
10
At least 30 days prior to establishing an IMAC for any substance, the Division of Water Resources
shall provide public notice that an IMAC has been requested. The public notice shall include the
petition requesting the establishment of the IMAC for a substance, the level of the proposed IMAC,
and the basis upon which the Division of Water Resources has relied in development of the proposed
IMAC. This notice shall be published in the North Carolina Register and posted on the Division of
Water Resources’s website: https://deq.nc.gov/about/divisions/water-resources/water-
planning/classification-standards/groundwater-imacs. If the Director of the Division of Water
Resources establishes an IMAC, the IMAC shall be posted on the Division of Water Resource’s
website and the Commission shall be notified in writing within 30 calendar days that a new IMAC
has been established.
9
10
E5
Proposed rule text revisions to 15A NCAC 02L .0202 (g)
11
(g)Groundwater quality standards specified in Paragraphs (h) and (i) of this Rule and interim maximum
allowable concentrations IMACs established pursuant to Paragraph (c) of this Rule shall be reviewed by the
Director Division of Water Resources on a triennial basis and reported to the Commission. The Director of the
Division of Water Resources shall consider the following actions during the review of an established IMAC:
(1) recommend codifying the IMAC as a groundwater quality standard under this rule;
(2) update the IMAC value based on data published or rescinded subsequent to the previous review;
(3) remove the IMAC based on data published or rescinded subsequent to the previous review;
(4) retain the IMAC at the current value;
Any IMAC recommended under Subparagraph (g)(1) of this Rule that the Commission does not codify shall
remain an established IMAC and be reviewed during the next triennial review.Appropriate Modifications to
established standards shall be made, through rulemaking, in accordance with the procedures prescribed in
Paragraph (d) and (e)of this Rule where modifications are considered appropriate based on data published
subsequent to the previous review.
• By state law, rule changes require a Regulatory Impact Analysis to be performed
on the proposed changes. The regulatory impact analysis was approved by
OSBM on August 30, 2019.
• A net direct benefit to regulated entities (savings in operation and maintenance
costs) and state government (staff time and resources) can be expected
• A zero to net positive indirect benefit for well water consumers and the
environment (increased remediation efforts leading to improved compliance with
groundwater standards) can be expected
•Regulatory Impact Analysis report can be found here:
https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-
standards/groundwater-standards
12
Fiscal Analysis
11
12
E6
13
Written comments may be mailed to:
Bridget Shelton, NC DEQ-DWR Planning Section,
1611 Mail Service Center, Raleigh, NC 27699-1611
Written comments may be emailed to:
[e-mail]
Comment period ends: March 16, 2021
More information can be found at:
https://deq.nc.gov/about/divisions/water-resources/water-
planning/classification-standards/groundwater-standards
13
E7
Name:Employer/Representing:
1 Shaun Malin HRP Associates, Inc.
2 Chris Gilbert Duke Energy
3 Liesel Werch GreenStory Global Water Filtration
4 Craig Caldwell NCDEQ
5 Dr. Sarah Cavrak (private citizen)
6 Aniruddha Dastidar Draper Aden Associates
7 Dacia Meng Beveridge & Diamond PC
8 Phoebe Gooding Toxic Free North Carolina
9 Tom Vitaglione NC Child
10 Candace Prusiewicz Self
11 Emily Donovan Clean Cape Fear
12 Todd Mickleborough The Quartz Corp
13 Emily Sutton Haw River Assembly
14 Anna Van Der Hurd Mother
15 Connor Kippe Climate Action NC
16 Roberta Waddle myself
17 Carrianne McClellan citizen
18 Michael Watters Grays Creek Residents United against PFAS in our Wells & Rivers
19 Elli Klein People living in the state and surrounding areas
20 Nita Dukes Chatham Climate Advisory Committee l
21 Terry Reilly Retired
22 Barry Self
23 Brian Beauregard Self Employed
24 Kathryn Self
25 Carrol Heiner NA
26 Barbara Sfraga Self
27 Edward Watson NCDEQ- DWR-MRO
28 Dana Sargent Cape Fear River Watch
29 Cassa Mason NHC resident
30 Grady McCallie NC Conservation Network
31 Suzanne Taylor None
32 Tom Vitaglione NC Child
33 Hope Taylor Clean Water for North Carolina
34 Greg Barnes NC Health News
35 Alexis Luckey Toxic Free North Carolina
36 Jennifer Hill Carrigan Circular Triangle
37 Lior Vered, PhD Toxic Free North Carolina
38 Courtney Bippley Myself
39 Rick Bolich DWR Groundwater Section
40 Brandon Jones Catawba Riverkeeper Foundation
41 Cori Bell Natural Resources Defense Council
42 Manny Mayfield Self
43 David Hill Self
44 Lauren Eaves UNC
45 Floyd Waddle self
46 Sherri White-Williamson N C Conservation Network
47 Brendan and Regina O'Donnell not applicable
48 Claire O'Donnell N/A
49 Brittany Johnston HRP Associates, Inc.
50 Emily Sutton Haw River Assembly
51 Lior Vered, Ph.D.Toxic Free North Carolina
52 Stan Frost Self
53 Beth Markesino North Carolina Stop Genx in our water
54 Christopher Scott Leyhew Self employed
55 Nita Dukes CCAC
56 cristina sanchez Baron & Budd
57 David Hill Self
Attachment F:
Public Hearing Registered Attendees
The hearing was called to order at 6:00 pm by Yvonne Bailey, the Environmental Management Commission-
appointed Hearing Officer. The hearing was adjourned at 7:19 pm. Below is a list of registered attendees.
Public Hearing on Proposed Rule Amendments and Regulatory Impact Analysis for 15A NCAC
02L .0202 Groundwater Quality Standards
February 2, 2021
F1
Name:Employer/Representing:Registered to speak?Spoke?
1 Emily Donovan Clean Cape Fear Yes Yes
2 Emily Sutton Haw River Assembly Yes Yes
3 Anna Van Der Hurd Self Yes No
4 Connor Kippe Climate Action NC Yes No
5 Roberta Waddle Self Yes No
6 Michael Watters Grays Creek Residents United against PFAS in our Wells & Rivers Yes Yes
7 Elli Klein People living in the state and surrounding areas Yes No
8 Brian Beauregard Self Yes No
9 Dana Sargent Cape Fear River Watch Yes Yes
10 Grady McCallie NC Conservation Network Yes Yes
11 Tom Vitaglione NC Child Yes Yes
12 Hope Taylor Clean Water for North Carolina Yes Yes
13 Jennifer Hill Carrigan Circular Triangle Yes No
14 Lior Vered, PhD Toxic Free North Carolina Yes Yes
15 Brandon Jones Catawba Riverkeeper Foundation Yes Yes
16 Cori Bell Natural Resources Defense Council Yes Yes
17 Manny Mayfield Self Yes Yes
18 Floyd Waddle Self Yes No
19 Brendan and Regina O'Donnell Self Yes Yes
20 Claire O'Donnell Self Yes Yes
21 Christopher Leyhew Self No Yes
22 Beth Markasino North Carolina Stop GenX in our Water No Yes
23 Manuel Fort Self No Yes
24 Katie Bryant Clean Haw River No Yes
Attachment G:
Public Hearing Speakers
G1
Attachment H:
Written Comments Received
All written comments received can be found on the DWR Groundwater
Triennial Review and Rulemaking website:
https://deq.nc.gov/about/divisions/water-resources/water-planning/
classification-standards/groundwater-standards
H1
Groundwater Interim Maximum Allowable
Concentration (IMAC) Summary Document
Division of Wa

ter Resources
PERFLUOROOCTANE SULFONIC ACID (CASRN 1763-23-1)
Health Effects Summary Human health effects associated with chronic, low environmental exposures to perfluorooctane sulfonic
acid (PFOS) are unknown. Perfluorooctane sulfonic acid is slowly eliminated and therefore accumulates in the human body. Its human serum biological half-life (time necessary for half of dose to be eliminated) is estimated to be approximately 2.9-5.8 years (Li et al. 2018; Olsen et al. 2007; Xu et al.
2020). The biological half-life of perfluorooctane sulfonic acid in other species, including rats and monkeys, is much smaller at 48-121 days (Chang et al. 2012).
Animals exposed to high doses of perfluorooctane sulfonic acid via ingestion exhibited decreased body weight, increased liver weight, increased liver fat, and liver histopathology. Animal reproductive and developmental studies reported decreased survival and weight of offspring. Animals exposed during gestation and lactation had offspring that exhibited higher serum glucose levels and insulin resistance as adults (U.S. EPA 2016). Epidemiological studies of workers exposed to perfluorooctane sulfonic acid via inhalation and general populations exposed via drinking water report increased total cholesterol and high-density lipoproteins (HDLs), and developmental and reproductive effects such as reduced fertility and fecundity (U.S. EPA 2016).
Data used for Groundwater IMAC U.S. EPA’s Office of Water established an oral reference dose (RfD) of 0.00002 mg/kg-day for perfluorooctane sulfonic acid based on decreased rat pup body weight in a two-generation reproductive study (https://www.epa.gov/sites/production/files/2016-05/documents/pfos_hesd_final_508.pdf_. A systemic threshold concentration of 0.14 µg/L can be calculated using the oral reference dose for perfluorooctane sulfonic acid in accordance with 15A NCAC 02L .0202(d)(1).
U.S. EPA considers perfluorooctane sulfonic acid as having “suggestive evidence of carcinogenic
potential” according to its 2005 Guidelines for Carcinogen Risk Assessment. Liver tumors were reported at the highest dose tested in a long-term rat study. However, there is lack of demonstrated genotoxicity and comparable human epidemiological evidence from workers exposed to perfluorooctane sulfonic acid. The U.S. EPA Office of Water has not derived a cancer slope factor for perfluorooctane sulfonic because the weight of evidence for human carcinogenic is limited. A human exposure concentration associated with an incremental lifetime cancer risk estimate of 1 x 10-6 cannot be calculated per the requirements of 15A NCAC 02L .0202(d)(2).
No aqueous odor threshold, aqueous taste threshold, federal maximum contaminant level (MCL) or secondary drinking water standard has been established for perfluorooctane sulfonic acid.
Recommended Groundwater IMAC
U.S. EPA Office of Water issued a Health Advisory and Health Effects Support Document for Perfluorooctane Sulfonic Acid (PFOS) in 2016. The Health Advisory of 0.07 µg/L was calculated based on reduced pup body weight using the 90th percentile drinking water intake and body weight of lactating women from the 2011 U.S. EPA Exposure Factors Handbook. Alternatively, the calculation provided by
the derivation of the non-cancer endpoint (0.1 ug/L) is advised.
Groundwater standards are to be the “lesser of” the criteria in 15A NCAC 02L .0202(d)(1-6).
I1
Attachment I
Groundwater Interim Maximum Allowable
Concentration (IMAC) Summary Document
Division of Water Resources

The recommended groundwater IMAC for perfluorooctane sulfonic acid (PFOS) is 0.07 ug/L (ppb) based on the calculated noncancer systemic threshold using the 90th percentile drinking water intake and body weight of lactating women. Uses Perfluorooctane sulfonic acid is used as a water and oil repellent and as a surfactant in firefighting foams. It is used in carpet, upholstery, and textiles in waterproofing and stain resistance applications. It is also used in food packaging as a paper grease proofing agent. It is commonly used as the sodium or potassium form of the acid. References Amoore, JE and Hautala E. 1983. Odor as an aid to chemical safety: Odor thresholds compared with threshold limit values and volatiles for 214 industrial chemicals in air and water dilution. Journal of Applied Toxicology,
Volume 3. No. 6.
Chang, S.-C., P.E. Noker, G.S. Gorman, S.J. Gibson, J.A. Hart, D.J. Ehresman, and J.L. Butenhoff.
2012. Comparative pharmacokinetics of perfluorooctanesulfonate (PFOS) in rats, mice and monkeys. Reproductive Toxicology 33:428–440.
Li, Y., Fletcher, T., Mucs, D., Scott, K., Lindh, C.H., Tallving, P. and Jakobsson, K., 2018. Half-lives
of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water. Occupational and environmental medicine, 75(1), pp.46-51.
Luebker, D.J., M.T. Case, R.G. York, J.A. Moore, K.J. Hansen, and J.L. Butenhoff. 2005b. Two-
generation reproduction and cross-foster studies of perfluorooctanesulfonate (PFOS) in rats. Toxicology 215:126–148.
Olsen, G.W., J.M. Burris, D.J. Ehresman, J.W. Froehlich, A.M. Seacat, J.L. Butenhoff, and L.R. Zobel. 2007. Half-life of serum elimination of perfluorooctanesulfonate, perfluorohexanesulfonate and perfluorooctanoate in retired fluorochemical production workers. Environmental Health Perspectives 115:1298–1305
U.S. EPA Drinking Water Standards and Health Advisories. 2012. Office of Water (EPA 822-S-12-001) https://www.epa.gov/sites/production/files/2015-09/documents/dwstandards2012.pdf
U.S. EPA Drinking Water Health Advisory for Perfluorooctane Sulfonic Acid (PFOS). 2016. Office of Water. (EPA 822-R-16-004) https://www.epa.gov/sites/production/files/2016- 05/documents/pfos_hesd_final_508.pdf
U.S. EPA Guidelines for Carcinogen Risk Assessment. 2005. (EPA/630/P-03/001B). Risk Assessment Forum, Washington, DC. (https://www.epa.gov/risk/guidelines-carcinogen-risk- assessment).
U.S. EPA Exposure Factors Handbook: 2011 Edition (Final). Office of Research and Development, National Center for Environmental Assessment. (EPA/600/R-09/052F).
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=236252
Xu, Y., Fletcher, T., Pineda, D., Lindh, C.H., Nilsson, C., Glynn, A., Vogs, C., Norström, K., Lilja, K., Jakobsson, K. and Li, Y., 2020. Serum half-lives for short-and long-chain perfluoroalkyl acids after
ceasing exposure from drinking water contaminated by firefighting foam. Environmental health perspectives, 128(7), p.077004.
Young WF, Horth H, Crane R, Ogden T and Arnott M. 1996. Taste and odour threshold concentrations
of potential potable water contaminants. Water Research, 30:2, pp. 331-340.
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Groundwater Interim Maximum Allowable
Concentration (IMAC) Summary Document
Division of Water Resources

PERFLUOROOCTANOIC ACID (PFOA) (CASRN 335-67-1)

Health Effects Summary Human health effects associated with chronic, low environmental exposures to perfluorooctanoic acid
(PFOA) are unknown. Perfluorooctanoic acid is slowly eliminated from humans and accumulates in the body. It has an estimated human biological half-life (time necessary for half of dose to be eliminated) of approximately 2-4 years (Bartell et al. 2010; Li et al. 2018; Olsen et al. 2007; Xu et al. 2020).
Animal studies reported liver toxicity including hypertrophy and necrosis, increased kidney weight, immune effects, developmental effects, and liver, testicular, and pancreatic cancer after oral exposures to perfluorooctanoic acid (U.S. EPA 2016). Epidemiological studies of workers exposed to perfluorooctanoic acid via inhalation and general populations exposed via drinking water report high
cholesterol, increased liver enzymes, decreased vaccination response, thyroid disorders, pregnancy induced hypertension and preeclampsia, and testicular and kidney cancer (U.S. EPA 2016). Data used for Groundwater IMAC U.S. EPA’s Office of Water established an oral reference dose (RfD) of 0.00002 mg/kg-day for perfluorooctanoic acid based on skeletal variations and accelerated puberty observed in male mice offspring (https://www.epa.gov/sites/production/files/2016-05/documents/pfoa_hesd_final_508.pdf). A systemic threshold concentration of 0.14 µg/L can be calculated using the oral reference dose for perfluorooctanoic acid in accordance with 15A NCAC 02L .0202(d)(1).
U.S. EPA considers perfluorooctanoic acid as having “suggestive evidence of carcinogenic potential” according to its 2005 Guidelines for Carcinogen Risk Assessment. U.S. EPA Office of Water derived a cancer slope factor of 0.07 (mg/kg-day) -1 for perfluorooctanoic acid based on testicular cancer (Leydig cells) observed in rats. A human exposure concentration of 0.50 µg/L associated with an incremental
lifetime cancer risk estimate of 1 x 10-6 can be calculated per the requirements of 15A NCAC 02L .0202(d)(2).
No aqueous odor threshold, aqueous taste threshold, federal maximum contaminant level (MCL) or secondary drinking water standard has been established for perfluorooctanoic acid. Recommended Groundwater IMAC An interim maximum allowable concentration (IMAC) of 2 µg/L was established under 15A NCAC 02L .0202(c) for perfluorooctanoic acid in 2006. New toxicological information relevant to the derivation of a North Carolina groundwater standard is available. U.S. EPA Office of Water issued a Health Advisory and Health Effects Support Document for Perfluorooctanoic Acid (PFOA) in 2016. The Health Advisory of 0.07 µg/L was calculated based on potential adverse effects for fetuses during pregnancy and breastfed
infants using the 90th percentile drinking water intake and body weight of lactating women from the 2011 U.S. EPA Exposure Factors Handbook. Alternatively, the calculation provided by the derivation of the non-cancer endpoint (0.1 µg/L) is advised.
Groundwater standards are to be the “lesser of” the criteria in 15A NCAC 02L .0202(d)(1-6). The recommended groundwater IMAC for perfluorooctanoic acid (PFOA) is 0.07 ug/L (ppb) based on the calculated noncancer systemic threshold using the 90th percentile drinking water intake and body weight of lactating women.
I3
Groundwater Interim Maximum Allowable
Concentration (IMAC) Summary Document
Division of Water Resources
Uses Perfluorooctanoic acid is used as a water and oil repellent, a surfactant in firefighting foams, and as an intermediate in the synthesis of fluoroacrylic esters. It is used in Teflon, floor waxes and polishes, outdoor
clothing and similar chemicals (known as fluorotelomers). According to the 2010/2015 EPA PFOA Stewardship Program, manufacture of PFOA was scheduled to be phased out by 2015.
References
Amoore, JE and Hautala E. 1983. Odor as an aid to chemical safety: Odor thresholds compared with threshold limit values and volatiles for 214 industrial chemicals in air and water dilution. Journal of Applied Toxicology, Volume 3. No. 6.
Bartell, S., A. Calafat, C. Lyu, K. Kato, P.B. Ryan, and K. Steenland. 2010. Rate of decline in serum PFOA concentrations after granular activated carbon filtration at two public water systems in Ohio
and West Virginia. Environmental Health Perspectives 118:222–228.
Li, Y., Fletcher, T., Mucs, D., Scott, K., Lindh, C.H., Tallving, P. and Jakobsson, K., 2018. Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water. Occupational and
environmental medicine, 75(1), pp.46-51.
Lau, C., J.R. Thibodeaux, R.G. Hanson, M.G. Narotsky, J.M. Rogers, A.B. Lindstrom, and M.J. Strynar. 2006. Effects of perfluorooctanoic acid exposure during pregnancy in the mouse. Toxicological Sciences
90:510–518.
Olsen, G.W., J.M. Burris, D.J. Ehresman, J.W. Froehlich, A.M. Seacat, J.L. Butenhoff, and L.R. Zobel. 2007. Half-life of serum elimination of perfluorooctanesulfonate, perfluorohexanesulfonate and perfluorooctanoate in retired fluorochemical production workers. Environmental Health Perspectives 115:1298–1305
U.S. EPA Drinking Water Standards and Health Advisories. 2012. Office of Water (EPA 822-S-12-001) https://www.epa.gov/sites/production/files/2015-09/documents/dwstandards2012.pdf
U.S. EPA Guidelines for Carcinogen Risk Assessment. 2005. (EPA/630/P-03/001B). Risk Assessment
Forum, Washington, DC. (https://www.epa.gov/risk/guidelines-carcinogen-risk- assessment).
U.S. EPA Health Effects Support Document for Perfluorooctanoic Acid (PFOA). 2016. Office of Water. (EPA 822-R-16-003)
https://www.epa.gov/sites/production/files/201605/documents/pfoa_health_advisory_final-plain.pdf
U.S. EPA Exposure Factors Handbook: 2011 Edition (Final). Office of Research and Development, National Center for Environmental Assessment. (EPA/600/R-09/052F).
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=236252
Young WF, Horth H, Crane R, Ogden T and Arnott M. 1996. Taste and odour threshold concentrations of potential potable water contaminants. Water Research, 30:2, pp. 331-340.
Xu, Y., Fletcher, T., Pineda, D., Lindh, C.H., Nilsson, C., Glynn, A., Vogs, C., Norström, K., Lilja, K., Jakobsson, K. and Li, Y., 2020. Serum half-lives for short-and long-chain perfluoroalkyl acids after ceasing exposure from drinking water contaminated by firefighting foam. Environmental health
perspectives, 128(7), p.077004.
I4

Total Perfluorooctane sulfonic acid (PFOS)
and Perfluorooctanoic acid (PFOA) CASRNs 1763-23-1 and 335-67-1

Summary
The North Carolina GW IMAC for total perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) is based on a
noncancer endpoint in accordance with selection criteria defined in 15A NCAC 02L .0202 (highlighted in yellow below).
Critical health effect: Reduced pup body weight, 2-generation rat gavage study (PFOS) and reduced ossification of the
forelimbs and hindlimbs and accelerated puberty in male mice pups (PFOA).
GW IMAC based on noncancer endpoint
GWQS = [(RfD x WT x RSC) / WI] * 1000 PFOS PFOA
RfD = reference dose1 2.0E-05 2.0E-05 mg/kg/day
WT = average adult human body weight2 70 70 kg
RSC= relative source contribution3 0.2 0.2 unitless value
WI = average daily human adult water intake4 2 2 L/day
1000 = conversion factor 1000 1000 µg/mg
Calculated GW Standard using noncancer endpoint 0.1 0.1 µg/L
GW IMAC based on cancer endpoint
GWQS = [(RL x WT) / (q1* x WI)] * 1000
RL = risk level 1.0E-06 1.0E-06
WT = average adult human body weight2 70 70 kg
q1* = carcinogenic potency factor (slope factor)5 NA 0.07 (mg/kg /day) -1
WI = average daily human adult water intake4 2 2 L/day
1000 = conversion factor 1000 1000 µg/mg

GW IMAC based on published values
Taste Threshold6
Odor Threshold7
Maximum Contaminant Level (MCL)8
Secondary Drinking Water Standard (SMCL)9
Additional Information
US EPA Health Advisory for PFOA/PFOS (2016)10

NA NA µg/L
NA NA µg/L
NA NA µg/L
NA NA µg/L
Practical Quantitation Limit (PQL)11 0.04 0.002 µg/L References
1 US EPA Drinking Water Health Advisory for Perfluorooctane sulfonic acid (PFOS). 2016. US EPA Office of Water (EPA 822-R-16-004);
US EPA Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA). 2016. US EPA Office of Water (EPA 822-R-16-005)
2 Average adult body weight from 15A NCAC 02L .0202 (effective date April 1, 2013).
3 RSC=0.1 for nonorganics, 0.2 for organics in accordance with 15A NCAC 02L .0202 (effective date April 1, 2013).
4 Average adult water consumption from 15A NCAC 02L .0202 (effective date April 1, 2013).
5 US EPA has not classified PFOS for carcinogenicity. A cancer slope factor is not available.
US EPA Office of Water derived a cancer slope factor for PFOA based on testicular cancer observed in rats. Human epidemiological studies evaluating the carcinogenicity of PFOA are equivocal for kidney and testicular cancer.US EPA Health Effects Support Document for Perfluorooctanoic Acid. 2016. US EPA Office of
Water (EPA 822-R-16-003)
6 NA; Contact NC DEQ Groundwater Standards Coordinator for list of taste threshold resources examined.
7 NA; Contact NC DEQ Groundwater Standards Coordinator for list of odor threshold resources examined.
8 NA; MCL: https://www.epa.gov/your-drinking-water/table-regulated-drinking-water-contaminants#Organic
9 NA; SMCL : https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals.
10 US EPA Office of Water derived the Health Advisory for PFOS using the 90th percentile consumers-only estimate of combined direct and indirect community water ingestion for lactating women (Table 3-81 in US EPA 2011 Exposure Factors Handbook). A value of 0.054 L/kg-day was used in the calculation which equates roughly
to 3.8 L of water consumed per day for a 65 Kg woman.
* EPA established equivalent Health Advisory Levels of 0.07 µg/L for PFOA and PFOS. The Health Advisory Level also applies to the sum total of both compounds if they co-occur.
11 PQL provided for informational purposes only. PQL not established by North Carolina Water Resources Laboratory. Using EPA Method 537, Pace Analytical reports a
PRL (ie- PQL) of 0.04 µg/L for PFOS and 0.002 µg/L for PFOA. (https://www.pacelabs.com/environmental-services/specialty-services/pfas-analysis.html)
North Carolina Groundwater (GW) IMAC =

0.07 µg/L*
North Carolina Groundwater
Interim Maximum Allowable Concentration (IMAC)
Calculation Sheet
I5
15A NCAC 02L .0202 GROUNDWATER QUALITY STANDARDS 1
(a) The groundwater quality standards for the protection of the groundwaters of the state are those specified in this2
Rule. They are the maximum allowable concentrations resulting from any discharge of contaminants to the land or 3
waters of the state, which may be tolerated without creating a threat to human health or which would otherwise render 4
the groundwater unsuitable for its intended best usage. 5
(b) The groundwater quality standards for contaminants specified in Paragraphs (h) and (i) of this Rule are as listed,6
except that: 7
(1)Where the standard for a substance is less than the practical quantitation limit, the detection of that8
substance at or above the practical quantitation limit constitutes a violation of the standard.9
(2)Where two or more substances exist in combination, the Director shall consider the effects of10
chemical interactions as determined by the Division of Public Health and may establish maximum11
concentrations at values less than those established in accordance with Paragraphs (c), (h), or (i) of12
this Rule. In the absence of information to the contrary, in accordance with Paragraph (d) of this13
Rule, the carcinogenic risks associated with carcinogens present shall be considered additive and14
the toxic effects associated with non-carcinogens present shall also be considered additive.15
(3)Where naturally occurring substances exceed the established standard, the standard shall be the16
naturally occurring concentration as determined by the Director.17
(4)Where the groundwater standard for a substance is greater than the Maximum Contaminant Level18
(MCL), the Director shall apply the MCL as the groundwater standard at any private drinking water19
well or public water system well that may be impacted.20
(c) Except for tracers used in concentrations which have been determined by the Division of Public Health to be21
protective of human health, and the use of which has been permitted by the Division, substances which are not 22
naturally occurring and for which no standard is specified shall not be permitted in concentrations at or above the 23
practical quantitation limit in Class GA or Class GSA groundwaters. Any person may petitionrequest the Director of 24
the Division of Water Resources to establish, update, or remove an interim maximum allowable concentration Interim 25
Maximum Allowable Concentration (IMAC) for a substance for which a standard has not been established under this 26
Rule. In response to this request, the Director may establish, update, or remove an IMAC. The petitionerrequestor 27
shall submit relevant toxicological and epidemiological data, study results, and calculations necessary to establish a 28
standard in accordance with Paragraphs (d) and (e) of this Rule. Within three months after the establishment of an 29
interim maximum allowable concentration for a substance by the Director, the Director shall initiate action to consider 30
adoption of a standard for that substance. If the information submitted is not in accordance with Paragraphs (d) and 31
(e) of this Rule, the Director of the Division of Water Resources shall request additional information from the32
petitionerrequester. If the petitionerrequester does not provide the additional information necessary to be in accordance 33
with Paragraphs (d) and (e) of this rule, the Director of the Division of Water Resources shall denyreturn the 34
petitionrequest. At least 30 days prior to establishing, updating, or removing an IMAC for any substance, the Division 35
of Water Resources shall provide public notice that an IMAC has been requested to be established, updated, or 36
removed. The public notice shall include the petitionrequest requestingfor the establishment, update, or removal of 37
J1
Attachment J:
NC DWR and Hearing Officer’s Recommended 02L .0202 Rule Text
the IMAC for a substance, the level of the proposed IMAC, if applicable the level of the existing IMAC, and the basis 1
upon which the Division of Water Resources has relied in development of the proposed IMAC establishment, update, 2
or removal. This notice shall be published in the North Carolina Register and posted on the Division of Water 3
Resources’s website: https://deq.nc.gov/about/divisions/water-resources/water-planning/classification-4
standards/groundwater-imacs. If the Director of the Division of Water Resources establishes or updates an IMAC, the 5
IMAC shall be posted on the Division of Water Resource’s website and the Commission shall be notified in writing 6
within 30 calendar days that a new IMAC has been established or an existing IMAC has been updated or removed. 7
(d) Except as provided in Paragraph (f) of this Rule, groundwater quality standards for substances in Class GA and8
Class GSA groundwaters are established as the least of: 9
(1)Systemic threshold concentration calculated as follows: [Reference Dose (mg/kg/day) x 70 kg (adult10
body weight) x Relative Source Contribution (.10 for inorganics; .20 for organics)] / [2 liters/day11
(avg. water consumption)];12
(2)Concentration which corresponds to an incremental lifetime cancer risk of 1x10-6;13
(3)Taste threshold limit value;14
(4)Odor threshold limit value;15
(5)Maximum contaminant level; or16
(6)National secondary drinking water standard.17
(e) The following references, in order of preference, shall be used in establishing concentrations of substances which18
correspond to levels described in Paragraph (d) of this Rule. 19
(1)Integrated Risk Information System (U.S. EPA).20
(2)Health Advisories (U.S. EPA Office of Drinking Water).21
(3)Other health risk assessment data published by the U.S. EPA.22
(4)Other relevant, published health risk assessment data, and scientifically valid peer-reviewed23
published toxicological data.24
(f) The Commission may establish groundwater standards less stringent than existing maximum contaminant levels25
or national secondary drinking water standards if it finds, after public notice and opportunity for hearing, that: 26
(1)more recent data published in the EPA health references listed in Paragraph (e) of this Rule results27
in a standard which is protective of public health, taste threshold, or odor threshold;28
(2)the standard will not endanger the public health and safety, including health and environmental29
effects from exposure to groundwater contaminants; and30
(3)compliance with a standard based on the maximum contaminant level or national secondary drinking 31
water standard would produce serious hardship without equal or greater public benefit.32
(g) Groundwater quality standards specified in Paragraphs (h) and (i) of this Rule and interim maximum allowable33
concentrations IMACs established pursuant to Paragraph (c) of this Rule shall be reviewed by the Director Division 34
of Water Resources on a triennial basis and reported to the Commission. The Director of the Division of Water 35
Resources shall considertake any of the following actions during the review of an established IMAC: 36
(1) recommend codifying the IMAC as a groundwater quality standard under this rule;37
J2
(2)update the IMAC value based on data published or rescinded subsequent to the previous review; 1
(3) remove the IMAC based on data published or rescinded subsequent to the previous review;2
(4) retain the IMAC at the current value;3
Any IMAC recommended under Subparagraph (g)(1) of this Rule that the Commission does not codify shall remain 4
an established IMAC and be reviewed during the next triennial review. Appropriate mModifications to established 5
standards shall be made, through rulemaking, in accordance with the procedures prescribed in Paragraph (d) and e of 6
this Rule where modifications are considered appropriate based on data published subsequent to the previous review. 7
(h) Class GA Standards. Unless otherwise indicated, the standard refers to the total concentration in micrograms per8
liter (µg/L) of any constituent in a dissolved, colloidal or particulate form which is mobile in groundwater. This does 9
not apply to sediment or other particulate matter which is preserved in a groundwater sample as a result of well 10
construction or sampling procedures. The Class GA standards are: 11
(1)Acenaphthene: 80;12
(2)Acenaphthylene: 200;13
(3)Acetone: 6 mg/L;14
(4)Acrylamide: 0.008;15
(5)Anthracene: 2 mg/L;16
(6)Arsenic: 10;17
(7)Atrazine and chlorotriazine metabolites: 3;18
(8)Barium: 700;19
(9)Benzene: 1;20
(10)Benzo(a)anthracene (benz(a)anthracene): 0.05;21
(11)Benzo(b)fluoranthene: 0.05;22
(12)Benzo(k)fluoranthene: 0.5;23
(13)Benzoic acid: 30 mg/L;24
(14)Benzo(g,h,i,)perylene: 200;25
(15)Benzo(a)pyrene: 0.005;26
(16)Bis(chloroethyl)ether: 0.03;27
(17)Bis(2-ethylhexyl) phthalate (di(2-ethylhexyl) phthalate): 3;28
(18)Boron: 700;29
(19)Bromodichloromethane: 0.6;30
(20)Bromoform (tribromomethane): 4;31
(21)n-Butylbenzene: 70;32
(22)sec-Butylbenzene: 70;33
(23)tert-Butylbenzene: 70;34
(24)Butylbenzyl phthalate: 1 mg/L;35
(25)Cadmium: 2;36
(26)Caprolactam: 4 mg/L;37
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(27)Carbofuran: 40;1
(28)Carbon disulfide: 700;2
(29)Carbon tetrachloride: 0.3;3
(30)Chlordane: 0.1;4
(31)Chloride: 250 mg/L;5
(32)Chlorobenzene: 50;6
(33)Chloroethane: 3,000;7
(34) Chloroform (trichloromethane): 70;8
(35)Chloromethane (methyl chloride): 3;9
(36)2-Chlorophenol: 0.4;10
(37)2-Chlorotoluene (o-chlorotoluene): 100;11
(38)Chromium: 10;12
(39)Chrysene: 5;13
(40)Coliform organisms (total): 1 per 100 mL;14
(41)Color: 15 color units;15
(42)Copper: 1 mg/L;16
(43)Cyanide (free cyanide): 70;17
(44)2, 4-D (2,4-dichlorophenoxy acetic acid): 70;18
(45)DDD: 0.1;19
(46)DDT: 0.1;20
(47)Dibenz(a,h)anthracene: 0.005;21
(48)Dibromochloromethane: 0.4;22
(49)1,2-Dibromo-3-chloropropane: 0.04;23
(50)Dibutyl (or di-n-butyl) phthalate: 700;24
(51)1,2-Dichlorobenzene (orthodichlorobenzene): 20;25
(52)1,3-Dichlorobenzene (metadichlorobenzene): 200;26
(53)1,4-Dichlorobenzene (paradichlorobenzene): 6;27
(54)Dichlorodifluoromethane (Freon-12; Halon): 1 mg/L;28
(55)1,1-Dichloroethane: 6;29
(56)1,2-Dichloroethane (ethylene dichloride): 0.4;30
(57)1,2-Dichloroethene (cis): 70;31
(58)1,2-Dichloroethene (trans): 100;32
(59)1,1-Dichloroethylene (vinylidene chloride): 350;33
(60)1,2-Dichloropropane: 0.6;34
(61)1,3-Dichloropropene (cis and trans isomers): 0.4;35
(62)Dieldrin: 0.002;36
(63)Diethylphthalate: 6 mg/L;37
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(64)2,4-Dimethylphenol (m-xylenol): 100; 1
(65)Di-n-octyl phthalate: 100;2
(66)1,4-Dioxane (p-dioxane): 3;3
(67)Dioxin (2,3,7,8-TCDD): 0.0002 ng/L;4
(68)1,1– Diphenyl (1,1,-biphenyl): 400;5
(69)Dissolved solids (total): 500 mg/L;6
(70)Disulfoton: 0.3;7
(71)Diundecyl phthalate (Santicizer 711): 100;8
(72)Endosulfan: 40;9
(73)Endrin, total (includes endrin, endrin aldehyde and endrin ketone): 2;10
(74)Epichlorohydrin: 4;11
(75)Ethyl acetate: 3 mg/L;12
(76)Ethylbenzene: 600;13
(77)Ethylene dibromide (1,2-dibromoethane): 0.02;14
(78)Ethylene glycol: 10 mg/L;15
(79)Fluoranthene: 300;16
(80)Fluorene: 300;17
(81)Fluoride: 2 mg/L;18
(82)Foaming agents: 500;19
(83)Formaldehyde: 600;20
(84)Gross alpha (adjusted) particle activity (excluding radium-226 and uranium): 15 pCi/L;21
(85)Heptachlor: 0.008;22
(86)Heptachlor epoxide: 0.004;23
(87)Heptane: 400;24
(88)Hexachlorobenzene (perchlorobenzene): 0.02;25
(89)Hexachlorobutadiene: 0.4;26
(90)Hexachlorocyclohexane isomers (technical grade): 0.02;27
(91)n-Hexane: 400;28
(92) Indeno(1,2,3-cd)pyrene: 0.05;29
(93)Iron: 300;30
(94)Isophorone: 40;31
(95)Isopropylbenzene: 70;32
(96)Isopropyl ether: 70;33
(97)Lead: 15;34
(98)Lindane (gamma hexachlorocyclohexane): 0.03;35
(99)Manganese: 50;36
(100)Mercury: 1;37
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(101)Methanol: 4 mg/L;1
(102)Methoxychlor: 40;2
(103)Methylene chloride (dichloromethane): 5;3
(104)Methyl ethyl ketone (2-butanone): 4 mg/L;4
(105)2-Methylnaphthalene: 30;5
(106)3-Methylphenol (m-cresol): 400;6
(107)4-Methylphenol (p-cresol): 40;7
(108)Methyl tert-butyl ether (MTBE): 20;8
(109)Naphthalene: 6;9
(110)Nickel: 100;10
(111)Nitrate (as N): 10 mg/L;11
(112)Nitrite (as N): 1 mg/L;12
(113)N-nitrosodimethylamine: 0.0007;13
(114)Oxamyl: 200;14
(115)Pentachlorophenol: 0.3;15
(116)Petroleum aliphatic carbon fraction class (C5 - C8): 400;16
(117)Petroleum aliphatic carbon fraction class (C9 - C18): 700;17
(118)Petroleum aliphatic carbon fraction class (C19 - C36): 10 mg/L;18
(119)Petroleum aromatics carbon fraction class (C9 - C22): 200;19
(120)pH: 6.5 - 8.5;20
(121)Phenanthrene: 200;21
(122)Phenol: 30;22
(123)Phorate: 1;23
(124)n-Propylbenzene: 70;24
(125)Pyrene: 200;25
(126)Selenium: 20;26
(127)Silver: 20;27
(128)Simazine: 4;28
(129)Styrene: 70;29
(130)Sulfate: 250 mg/L;30
(131) 1,1,2,2-Tetrachloroethane: 0.2;31
(132)Tetrachloroethylene (perchloroethylene; PCE): 0.7;32
(133) 2,3,4,6-Tetrachlorophenol: 200;33
(134)Toluene: 600;34
(135)Toxaphene: 0.03;35
(136)2,4,5-TP (Silvex): 50;36
(137)1,2,4-Trichlorobenzene: 70;37
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(138)1,1,1-Trichloroethane: 200; 1
(139)Trichloroethylene (TCE): 3;2
(140)Trichlorofluoromethane: 2 mg/L;3
(141)1,2,3-Trichloropropane: 0.005;4
(142)1,2,4-Trimethylbenzene: 400;5
(143)1,3,5-Trimethylbenzene: 400;6
(144)1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113): 200 mg/L;7
(145)Vinyl chloride: 0.03;8
(146)Xylenes (o-, m-, and p-): 500; and9
(147)Zinc: 1 mg/L.10
11
Substance Chemical Abstracts
Service (CAS) Registry
Number
Standard (µg/L)
Acenaphthene 83-32-9 80
Acenaphthylene 208-96-8 200
Acetic acid 64-19-7 5,000
Acetochlor 34256-82-1 100
Acetochlor ESA 187022-11-3 500
Acetochlor OXA 184992-44-4 500
Acetone 67-64-1 6,000
Acetophenone 98-86-2 700
Acrolein 107-02-8 4
Acrylamide 79-06-1 0.008
Alachlor 15972-60-8 2
Aldrin 309-00-2 0.002
Anthracene 120-12-7 2,000
Antimony 7440-36-0 1
Arsenic 7440-38-2 10
Atrazine and chlorotriazine metabolites 1912-24-9 3
Barium 7440-39-3 700
Benzene 71-43-2 1
Benzo(a)anthracene 56-55-3 0.05
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Benzo(a)pyrene 50-32-8 0.005
Benzo(b)fluoranthene 205-99-2 0.05
Benzo(g,h,i)perylene 191-24-2 200
Benzo(k)fluoranthene 207-08-9 0.5
Benzoic acid 65-85-0 30,000
Benzyl alcohol 100-51-6 700
Beryllium 7440-41-7 4
Bis(chloroethyl)ether 111-44-4 0.03
Bis(2-ethylhexyl) phthalate 117-81-7 3
Boron 7440-42-8 700
Bromodichloromethane 75-27-4 0.6
Bromoform 75-25-2 4
Bromomethane 74-839-9 10
n-Butanol 71-36-3 590
sec-Butanol 78-92-2 10,000
n-Butylbenzene 104-51-8 70
sec-Butylbenzene 135-98-8 70
tert-Butylbenzene 98-06-6 70
Butylbenzyl phthalate 85-68-7 1,000
Cadmium 7440-43-9 2
Caprolactam 105-60-2 4,000
Carbofuran 1563-66-2 40
Carbon disulfide 75-15-0 700
Carbon tetrachloride 56-23-5 0.3
Chlordane 12789-03-6 0.1
Chloride 16887-00-6 250,000
Chlorobenzene 108-90-7 50
Chloroethane 75-00-3 3,000
Chloroform 67-66-3 70
Chloromethane 74-87-3 3
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2-Chlorophenol 95-57-8 0.4
2-Chlorotoluene 95-49-8 100
4-Chlorotoluene 106-43-4 24
Chromium 7440-47-3 10
Chrysene 218-01-9 5
Cobalt 7440-48-4 1
Coliform organisms (total) 1 per 100 mL
Color 15 color units
Copper 7440-50-8 1,000
Cyanide (free cyanide) 57-12-5 70
2,4-D (2,4-dichlorophenoxy acetic acid) 94-75-7 70
Dalapon 75-99-0 200
DDD 72-54-8 0.1
DDE 72-55-9 0.1
DDT 50-29-3 0.1
Dibenz(a,h)anthracene 53-70-3 0.005
1,4-Dibromobenzene 106-37-06 70
Dibromochloromethane 124-48-1 0.4
1,2-Dibromo-3-chloropropane 96-12-8 0.04
Dibutyl phthalate 84-74-2 700
Dichloroacetic acid 79-43-6 0.7
1,2-Dichlorobenzene 95-50-1 20
1,3-Dichlorobenzene 541-73-1 200
1,4-Dichlorobenzene 106-46-7 6
Dichlorodifluoromethane 75-71-8 1,000
1,1-Dichloroethane 75-34-3 6
1,2-Dichloroethane 107-06-2 0.4
1,2-Dichloroethene (cis) 156-59-2 70
1,2-Dichloroethene (trans) 156-60-5 100
1,1-Dichloroethylene 75-35-4 350
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2,4-Dichlorophenol 120-83-2 0.98
1,2-Dichloropropane 78-87-5 0.6
1,3-Dichloropropene (cis and trans isomers) 542-75-6 0.4
Dieldrin 60-57-1 0.002
Diethylphthalate 84-66-2 6,000
2,4-Dimethylphenol 105-67-9 100
2,4-Dinitrotoluene 121-14-2 0.05
2,6-Dinitrotoluene 606-20-2 0.05
Di-n-octyl phthalate 117-84-0 100
Dinoseb 88-85-7 7
1,4-Dioxane 123-91-1 3
Dioxin (2,3,7,8-TCDD) 1746-01-6 0.0002 ng/L
1,1-Diphenyl 92-52-4 400
Diphenyl ether 101-84-8 180
Diquat 85-00-7 20
Dissolved solids (total) 500,000
Disulfoton 298-04-4 0.3
Diundecyl phthalate (Santicizer 711) 3648-20-2 100
Endosulfan 115-29-7 40
Endosulfan sulfate 115-29-7 40
Endothall 145-73-3 100
Endrin, total (includes endrin, endrin aldehyde, and
endrin ketone)
72-20-8 2
Epichlorohydrin 106-89-8 4
Ethyl acetate 141-78-6 3,000
Ethylbenzene 100-41-4 600
Ethylene dibromide 106-93-4 0.02
Ethylene glycol 107-21-1 10,000
Fluoranthene 206-44-0 300
Fluorene 86-73-7 300
Fluoride 16984-48-8 2,000
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Foaming agents 500
Formaldehyde 50-00-0 600
Gross alpha (adjusted) particle activity (excludes
radium-226 and uranium)
12587-46-1 15 pCi/L
Heptachlor 76-44-8 0.008
Heptachlor epoxide 1024-57-3 0.004
Heptane 142-82-5 400
Hexachlorobenzene 118-74-1 0.02
Hexachlorobutadiene 87-68-3 0.4
Hexachlorocyclohexane isomers (technical grade) 608-73-1 0.02
alpha-Hexachlorocyclohexane 319-84-6 0.006
beta-Hexachlorocyclohexane 319-85-7 0.02
gamma-Hexachlorocyclohexane (Lindane) 58-89-9 0.03
n-Hexane 110-54-3 400
Indeno(1,2,3-cd)pyrene 193-39-5 0.05
Iron 7439-89-6 300
Isophorone 78-59-1 40
Isopropyl ether 108-20-3 70
Isopropylbenzene 98-82-8 70
4-Isopropyltoluene 99-87-6 25
Lead 7439-92-1 15
Manganese 7439-96-5 50
Mercury 7439-97-6 1
Methanol 67-56-1 4,000
Methoxychlor 72-43-5 40
Methylene chloride 75-09-2 5
Methyl butyl ketone 591-78-6 40
Methyl ethyl ketone 78-93-3 4,000
Methyl isobutyl ketone 108-10-1 100
Methyl methacrylate 80-62-6 25
1-Methylnapthalene 90-12-0 1
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2-Methylnaphthalene 91-57-6 30
2-Methylphenol 95-48-7 400
3-Methylphenol 108-39-4 400
4-Methylphenol 106-44-5 40
Methyl tert-butyl ether (MTBE) 1634-04-4 20
Naphthalene 91-20-3 6
Nickel 7440-02-0 100
Nitrate (as N) 14797-55-8 10,000
Nitrite (as N) 14797-65-0 1,000
N-nitrosodimethylamine 62-75-9 0.0007
Oxamyl 23135-22-0 200
Pentachlorophenol 608-93-5 0.3
Perfluorooctane sulfonic acid (PFOS) and
Perfluorooctanoic acid (PFOA), total
1763-23-1 (PFOS);
335-67-1 (PFOA) 0.07
Petroleum aliphatic carbon fraction class (C5 – C8) 400
Petroleum aliphatic carbon fraction class (C9 – C18) 700
Petroleum aliphatic carbon fraction class (C19 – C36) 10,000
Petroleum aromatics carbon fraction class (C9 – C22) 200
pH 6.5 - 8.5 (no unit)
Phenanthrene 85-01-8 200
Phenol 108-95-2 30
Phorate 298-02-2 1
n-Propylbenzene 103-65-1 70
Propylene glycol 57-55-6 100,000
Pyrene 129-00-0 200
Selenium 7782-49-2 20
Silver 7440-22-4 20
Simazine 122-34-9 4
Strontium 7440-24-6 2,000
Styrene 100-42-5 70
Sulfate 14808-79-8 250,000

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1,2,4,5-Tetrachlorobenzene 95-94-3 2
1,1,2,2-Tetrachloroethane 79-34-5 0.2
1,1,1,2-Tetrachloroethane 630-20-6 1
Tetrachloroethylene (PCE) 127-18-4 0.7
2,3,4,6-Tetrachlorophenol 58-90-2 200
Thallium 7440-28-0 2
Tin (inorganic forms) 7440-31-5 2,000
Toluene 108-88-3 600
Toxaphene 8001-35-2 0.03
2,4,5-TP (Silvex) 93-72-1 50
1,2,4-Trichlorobenzene 120-82-1 70
1,1,1-Trichloroethane 71-55-6 200
1,1,2-Trichloroethane 79-00-5 0.6
Trichloroethylene (TCE) 79-01-6 3
Trichlorofluoromethane 75-69-4 2,000
2,4,5-Trichlorophenol 95-95-4 63
2,4,6-Trichlorophenol 88-06-2 4
1,2,3-Trichloropropane 96-18-4 0.005
1,2,4-Trimethylbenzene 95-63-6 400
1,3,5-Trimethylbenzene 108-67-8 400
Vanadium 7440-62-2 7
1,1,2-Trichloro-1,2,2-trifluoroethane 76-13-1 200,000
Vinyl chloride 75-01-4 0.03
Xylenes 1330-20-7 500
Zinc 7440-66-6 1,000
1
(i)Class GSA Standards. The standards for this class are the same as those for Class GA except as follows:2
(1)chloride: allowable increase not to exceed 100 percent of the natural quality concentration; and3
(2)dissolved solids (total): 1000 mg/L.4
(j) Class GC Standards.5
(1)The concentrations of substances that, at the time of classification, exceed the standards applicable6
to Class GA or GSA groundwaters shall not be caused to increase, nor shall the concentrations of7
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other substances be caused to exceed the GA or GSA standards as a result of further disposal of 1
contaminants to or beneath the surface of the land within the boundary of the area classified GC. 2
(2)The concentrations of substances that, at the time of classification, exceed the standards applicable3
to GA or GSA groundwaters shall not be caused to migrate as a result of activities within the4
boundary of the GC classification, so as to violate the groundwater or surface water quality standards 5
in adjoining waters of a different class.6
(3)Concentrations of specific substances, that exceed the established standard at the time of7
classification, are listed in Section .0300 of this Subchapter.8
9
History Note: 10
11
12
13
14
15
16
17
18
Authority G.S. 143-214.1; 143B-282(a)(2);
Eff. June 10, 1979;
Amended Eff. November 1, 1994; October 1, 1993; September 1, 1992; August 1, 1989;
Temporary Amendment Eff. June 30, 2002;
Amended Eff. August 1, 2002;
Temporary Amendment Expired February 9, 2003;
Amended Eff. April 1, 2013; January 1, 2010; April 1, 2005;
Pursuant to G.S. 150B-21.3A, rule is necessary without substantive public interest Eff. March 6,
2018.
Amended Eff. February 1, 2022 19
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