DEQ-CFW_00004239

Information will be presented on 20 1 MACs recently established by the DWQ Director
inaccordance with the 2LGroundwater Regulations
in response to requests from the Division of Waste Management, Monsanto Company and Brewster Environmental.
Attachment A of GWC information packet contains a copy of each I MAC request

[W regulations grant the DWQ Director authority to establish an|MAC when requested inorder to act quickly to address
potential public health concerns that may arise, and in some cases to establish more cost-effective groundwater cleanup
targets
Kcan take upto2'3years bodevelop ahealth-based gw standard through the APAnu|omakingprocess. However, itcan
take as little as 3 months to established an enforceable health based interim concentration
When there is not a health -based groundwater standard or IMAC for a substance, a detection at or above the PQL of that
substance constitutes a 2L violation.
POLaare "tech no|ogy'baaed.rather thanhek-baeod.
Some relatively non -toxic substances may be "overregulated" at the PQL.
Both Regulators and regulated public use I MACs and gw standards to aid in assessing the risks of exposure to
contaminants detected in groundwater, and to determine compliance with the rules;
Health -based gw standards and I MACs aid in prioritizing contaminated sites and remediation strategies at sites based on

|MACeare established using the same criteria aethe ^penmanent"standards listed inparagraph gofthe rule.
Per paragraph (d) of the Rule a GW Standard or IMAC is established as the lower of:
• level protective ofnon-cancer effects such aoliver and kidney disease
Alevel protective ofcancer effects at1/niUioncancer risk
Alevel protective oftaste & odor effects
The federal M[|L' a health based primary drinking water standard
The Secondary DW Std—federal guidelines to address aesthetic effects such as taste, odor, color and cosmetic effects
such aaskin ortooth discoloration inpublic drinking water supplies
Only difference between permanent standard and |K4ACnkathat
Permanent standards have already been through APA rulemaking process (public hearing, public comment period,
preparation of a fiscal analysis to estimate fiscal impact of these IMACs to potentially affected parties, etc .... ).
IMACs are interim concentrations for use until they can be taken through the rulemaking process to become permanent
standards. Rules require that Director initiate action to consider adoption of a standard for an IMACs within 3 months of
establishment.
OEQ-CFVV_00004241

emphasize interagency review
IMAC requests are reviewed by DWQ staff to ensure completeness and compliance with the regulations
IMAC requests are submitted to DPH state toxicologist and DWM toxicologists for review and concurrence on interim
concentration
Once approved byDirector,
EMC chairman and GWC chairman notified of established I MACs and effective date
|K1ACa published in NC ReAiotor, email notification iasent out ho nu|emaNng and stakeholder lists and the groundwater

5|MACewere established, effective 12/1/1O aearesult ofrequests from Monsanto and DVVK4
GVVCdid not meet inNovember 2O1U
Information was provided electronically to GWC members in an October 2010 email from Kevin Martin-- Public notice,
summary table, and narrative summary.
Summary of information used to establish these IMACs provided in color -coded table in Attachment B (information
provided includes the requested and established IMAC, the 6 criteria used to established an IMAC in accordance with GW
regulations, basis of|MAC.
More in-depth narrative for each |K4AC in Attachment D includes health effects and uo*e for these substances
Note: all 5 1 MACs above PQLs so compliance cost savings

Requests received in Nov 2010 from Brewster and DWM have been through the review process and I MACs established
for 15of18requested, effective April 1.2U11
Note numbers don't add upbecause 17requested but 15established.
4-ioopnop}4to|uenerequested byboth Brewster and DVVK8
An I MAC has not been established for TBA --- waiting for forthcoming information from EPA.
2-hexannn*kaanupdate tothe current |MAC--notestablishing new |MAC
Attachment C of your package contains summary table of information used to establish I MACs
Attachment D contains information in narrative form and includes potential health effects and how substances are used.
Note: Of 15 IMACs in summary table, 8 IMACs > PQLs so potential cost savings for regulated public; 4 IMACs < PQLs;
Costs could be incurred for IMACs < PQL if a regulatory agency requires a more sensitive analytical method, if one is
available, that costs more and ienot already being required.

Estimated timeline for adoption of|K4ACnaepermanent standards
The Director has requested that these I MACs betaken forward and proposed as permanent standards during the 2010-
2012Thonnia|Revew.
Currently, staff is in the process of reviewing permanent standard to determine if any revisions are needed.
Goal is to send proposed revisions in April to DPH, DWM for 60-day review per DWO SOP for reviewing GW Stds
Once a final determination has been made on needed changes, staff will prepare revised groundwater rules and return to
GVVCfor approval.
After GVVCapproval ofproposed changes, staff will begin b) prepare fiscal analysis
Once draft fiscal analysis prepared will return bothe GVVCfor review and permission boproceed bofull EMCaainformation

i • i '. i'. i • - to c • i. i ' i ' i'.
4 IMAC requests have been received by the DWQ for a total of 58 IMACs requested,
54 from DWM
3 from Monsanto (Acetochlor and ESA and OXA degradates
1 from Brewster (4-isopropyl toluene) also requested by DWM)
1 IMAC not approved (Cr III), 1 duplicate request (4-isopropyltoluene), 1 pending (TBA), 1 update (2-hexanone),
So far, 54 IMACs established as of April 1, 2011 and will be taken forward for incorporation as permanent standards
during 2010-12 GWTR
DEQ-CFW 00004247

Go over definition in the rule definitions in .0102 (15)
Point out
When the PQL is lower than what the calculated health based concentration would be for a contaminant
then regulation at the PQL increases compliance/ assessment /clean up costs with little or no health benefit.
Stress Point:
When a std or IMAC exists, regulated parties can base actions and expenditure of resources to clean up contaminants
which pose greater risk rather than
whether ornot the contaminant iasimply detected ornot.
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