Presentation_02L-PFASGWStandards_Sep2024

15A NCAC 02L .0202 Groundwater Quality Standards PFAS Rulemaking
Bridget Shelton
Division of Water Resources
September 2024 GWWMC
Jessica Montie
Division of Waste Management
Outline
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•Groundwater Quality Standards Background
•Development of Groundwater Quality Standards
•Per-and Polyfluoroalkyl Substances (PFAS)
•Proposed Groundwater Quality Standards for PFAS
•Regulatory Impact Analysis Summary
•Follow-Up to Questions from July 2024 GWWMC Meeting
•Proposed Rulemaking Schedule and Action Item Request
Groundwater Quality Standards Rule
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Title 15A NCAC Subchapter 02L – Groundwater Classifications and Standards
Section .0100: General Considerations
Section .0200: Classifications and Groundwater Quality Standards
.0201 Groundwater Classifications
.0202 Groundwater Quality Standards
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
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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 groundwater unsuitable 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
•Groundwater supports approximately 50% of drinking water use in the state
•Implemented in various programs including site clean-ups, risk assessments, health evaluations, etc.
*Groundwater standards are used in Federal programs in NC (such as
Superfund, RCRA, etc.)
•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 (PQL).
•Where the standard for a substance is less than the PQL, the
detection of that substance at or above the PQL constitutes a
violation of the standard.
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Groundwater Quality Standards Rule Language
15A NCAC 02L .0202 (b) and (c)
Practical quantitation limit or "PQL" means the lowest concentration of a
given material that can be reliably achieved by analytical technique
during routine laboratory analysis.
Established as the least of the following*:
1.Systemic/non-cancer threshold concentration
2.Concentration which corresponds to an incremental lifetime cancer
risk of 1 x 10-6 (one in a million)
3.Taste threshold limit value
4.Odor threshold limit value
5.Maximum contaminant level
6.National secondary drinking water standard
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Developing Groundwater Quality Standards
*15A NCAC 02L .0202 (d)
The following references are used, in order of preference*:
1.EPA Integrated Risk Information System (IRIS)
2.EPA Drinking Water Health Advisories
3.Other EPA health risk assessment data
4.Other relevant, published health risk assessment data and
scientifically valid peer-reviewed published toxicological data
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*15A NCAC 02L .0202 (e)
Developing Groundwater Quality Standards cont.
Per- and Polyfluoroalkyl Substances (PFAS)
•PFAS are a group of manufactured chemicals that are used to make
fluoropolymer coatings and products
•Perfluorinated compounds are chemicals of specific concern to North Carolina
•Widely produced and used; significant presence in NC
•Persist in the environment
•Bioaccumulate in humans, animals, and the environment
•Evaluated the available scientific data to develop groundwater standards for a
subset of PFAS compounds
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Background- Previous GWWMC and EMC Presentations
2022-2023
•May 2022 EMC Meeting
•Information Item – Prevalence of PFAS in NC,
EPA actions, and regulations in other states
•July 2022 EMC Meeting
•Information Item – PFAS Update
•July 2023 GWWMC Meeting
•Information Item – Groundwater Quality
Standards and PFAS Rulemaking Update
•November 2023 EMC Meeting
•Information Item – Proposed PFAS Toxicological
Summaries
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2024
•January 2024 GWWMC Meeting
•Information Item – Affected Sources and Anticipated
Implementation Requirements; Cost and Benefits
Analysis Approach
•March 2024 GWWMC Meeting
•Information Item – Plan Implementation Timeline;
DWM Stakeholder Meetings Overview and Feedback
•May 2024 GWWMC Meeting
•Information Item – Proposed Groundwater Standards;
Regulatory Impact Analysis Overview
•July 2024 GWWMC Meeting
•Action Item – Proposed Groundwater Standards;
Regulatory Impact Analysis Overview
Compounds Initially Proposed by DEQ for
Groundwater Standards Development
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PFAS Compound Acronym
1 Perfluorooctane sulfonic acid PFOS*
2 Perfluorooctanoic acid PFOA*
3 Hexafluoropropylene oxide dimer acid HFPO-DA (GenX)*
4 Perfluorobutane sulfonic acid PFBS*
5 Perfluorononanoic acid PFNA*
6 Perfluorohexane sulfonic acid PFHxS*
7 Perfluorobutanoic acid PFBA
8 Perfluorohexanoic acid PFHxA
*Regulated under the Safe Drinking Water Act in the form of MCLs and Hazard Index.
Background- July 2024 GWWMC Meeting
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•DEQ presented the Proposed Rule and certified Regulatory Impact Analysis (RIA) for 8 PFAS to the GWWMC in July 2024.
•PFOS, PFOA, HFPO-DA (GenX), PFBS, PFNA, PFHxS, PFBA, PFHxA
•The GWWMC voted to have DEQ revise the rulemaking package to address proposed standards for 3 PFAS: PFOA, PFOS, and HFPO-DA (GenX), and return to the GWWMC with the agenda item as revised.
•DEQ has revised the Proposed Rule and RIA accordingly and resent to OSBM for approval. OSBM approved the revised RIA on August 14, 2024.
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Compound Reference
Toxicity
Benchmarks and
Values Available*
Proposed 02L
Standard (ng/L)
1 PFOS 2023 EPA Toxicity Assessment+RfD, CSF, MCL 0.7
2 PFOA 2023 EPA Toxicity Assessment+RfD, CSF, MCL 0.001
3 HFPO-DA (GenX)2021 EPA Human Health Toxicity Assessment+RfD, MCL 10
Proposed Groundwater Standards for PFAS Compounds
See Appendix A for Details on Toxicological Summary and Derivation of the Standard
+Used as basis for EPA's PFAS National Primary Drinking Water Regulation​*RfD: reference dose; CSF: cancer slope factor; MCL: Maximum Contaminant Level in drinking water
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Proposed Groundwater Standards for 3 PFAS
15A NCAC 02L .0202 (b)(1):
Where the standard for a
substance is less than the PQL,
the detection of that substance at
or above the PQL constitutes a
violation of the standard.
Compound Proposed 02L
Standard (ng/L)
Existing 02L
Limit – PQL*
(ng/L)
Compliance Level
Under Proposed
Rule if Adopted
(ng/L)
1 PFOS 0.7 4.0 PQL **
2 PFOA 0.001 4.0 PQL **
3 HFPO-DA
(GenX)10 5.0 10
( * ) PQLs were calculated using the method detection limits (MDLs) reported in EPA Method 1633, which were based on the national
Multi-Laboratory Validation Study of PFAS by Isotope Dilution LC-MS/MS Wastewater, Surface Water, and Groundwater.
( ** ) The applicable regulatory limit will be the PQL per 15A NCAC 02L .0202(b)(1), unless or until the PQL decreases to a level that
is at or below the proposed standard, if adopted. The EPA-published PQL at the time of this rulemaking for PFOA and PFOS is 4 ng/L.
However, the PQL can vary based on laboratory capability or over time.
Regulatory Impact Analysis
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•The Fiscal and Regulatory Impact Analysis (RIA) was revised to address standards for only PFOA, PFOS, and HFPO-DA (GenX) and remove analysis for proposed standards for the other 5 PFAS, as requested by the GWWMC at their July 2024 meeting.
•The RIA was also revised for clarification in response to multiple questions and comments provided during and after the July meeting (see also Attachment C).
•Table VII-7 of the RIA was also updated to reflect additional results received for analysis of PFAS at landfills since the original RIA was approved by OSBM.
•The amounts for cost savings in Tables VII-8 and VIII-2 were revised to remove the treatment option that combined GAC and IX, as this option would not need to be used at a site that met the conditions for cost savings.
Regulatory Impact Analysis
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•5 of the 6 PFAS previously proposed standards that were higher than the existing regulatory limit at the PQL were removed from the analysis.
•Since PFAS data is still being collected, the potential for future cost savings resulting from the proposed higher standard for GenX has not been ruled out.
•If one site met the criteria listed in the RIA for potential future cost savings, that potential savings could still be a substantial economic impact.
Regulatory Impact Analysis – Impact Summary
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•No change to overall conclusion of the RIA from earlier version of RIA that addressed 8 PFAS:
•Potential for future savings to state government staff time that can be used at other sites.
•No additional costs to the regulated community.
•Potential for future cost savings at sites as a result of the proposed amendment.
•Potential savings at just one site could be a substantial economic impact.
•Benefit of regulatory certainty and clarification.
•The revised RIA was approved by the Office of State Budget and Management as required by G.S. 150B-21.4.
Questions Provided Following theJuly 2024 GWWMC Meeting
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•Attachment C provides a summary of additional questions and comments received from the GWWMC following their July 10, 2024, meeting regarding the RIA.
•Questions and comments were either addressed by adding clarification to the RIA as noted in the attachment, or a response is provided in the attachment.
Action / Responsibility Date
Stakeholder Meetings January and February 2024
GWWMC/EMC Information Item Presentations May and July 2022; July and November
2023; and January, March, and May
2024
GWWMC – Decision to revise RIA to include only PFOA, PFOS,
and GenX and return to GWWMC July 10, 2024
GWWMC – Decision to Approve Rule Text and RIA to go to
EMC September 11, 2024
EMC – Decision to Approve Rule and RIA for Public Comment November 14, 2024
Public Comment Period December 2024 – February 2025
EMC – Decision to Approve Hearing Officer’s Report and final
RIA, Adopt Rule May 2025
RRC – Approval of Rule June 2025
Proposed effective date, if approved July 2025
Proposed Rulemaking Schedule
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Action Item Request
Approval to proceed to the EMC with request for public notice and
hearings for the proposed rule amendment to 15A NCAC 02L .0202
Groundwater Quality Standards and the associated Fiscal and
Regulatory Impact Analysis.
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Thank you
Groundwater Standards Calculations:
Bridget Shelton
Groundwater Quality Standards Coordinator, DWR
[e-mail]; (919)-707-9022
Human Health Impacts:
Frannie Nilsen, PhD
Environmental Toxicologist, DEQ
[e-mail]​; (919)-707-8217
Regulatory and Fiscal Impact Analysis and Rule Implementation:
Jessica Montie
Environmental Program Consultant, DWM
[e-mail]​;(919)-707-8247