Committee Update: Review of Groundwater Standards/IMACs Connie Brower Classifications and Standards/Rules Review Branch

15A NCAC 02L Groundwater Standards Interim Maximum Allowable Concentrations 15A NCAC 02L .0200 institutes that the EMC is responsible for establishing groundwater standards to protect public health. Interim Maximum Allowable Concentrations (IMACS) may be established by the Director of DWR when no applicable standard exists. Since the last revision to 15A NCAC 02L, a number of IMACs have been established by the Director and are being reevaluated with the purpose of providing recommendations to the EMC for adoption as Groundwater Standards.

North Carolina IMACs Currently, 58 IMACS have been established. Most were requested by the Division of Waste Management (DWM) or regulated parties. As regulated sites are required to clean-up to a Practical Quantitation Level if no standards exist, IMACs serve a valued purpose in the regulated community. DWR staff have been working with DWM and Department of Health and Human Services (DHHS) to review the 58 established IMACs.

The IMAC Review Process The established IMACs are reviewed in small batches of ~ 6 -12 parameters at a time. DWR staff reviews toxicological research and literature for each IMAC to document compliance with 15A NCAC 02L regulations. Internal reports prepared/reviewed DWR Director submits proposals to DWM and DHHS staff for concurrence and/or further discussion as outlined in established SOP After determining a course of action for each IMAC, staff begins review of the next “batch”

IMAC Review Status Evaluation is complete for 24 IMACs DWR has submitted an additional 28 IMACs for review and evaluation Noting that a number of these are still in the Review Process, the following estimates may be revised: ~ 35 IMACs remain unchanged from the original established value, ~3 IMACs may be elevated, ~5 IMACs may be lowered, ~ 9 IMACs may be modified to more clearly define the chemical or chemical forms

North Carolina IMACs and Groundwater Standards * Time-frame Temporary Permanent Regulatory Framework 15 NCAC 02L . 0202 Scientific Review Process DPH/DWM secondary review Public Comment No Yes Public Hearing Fiscal Analysis Public Notification of Value Yes (NC Register) Yes (NC Register and Rule) Legally Enforceable Approval Process Division of Water Resources Director Environmental Management Commission * IMAC = Interim Maximum Allowable Concentration

Next Steps DWR to complete review of remaining IMACs/submit for DWM and DHHS review Prepare Committee proposals to amend 15A NCAC 02L to include these updated GW standards Begin determination of costs/benefits for submission under GS 150B requirements for a fiscal analysis

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