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DEC Issues Ambient Water Quality Guidance Values to Advance New York State's Regulation of Emerging Contaminants PFOA, PFOS, and 1, 4-Dioxane

Finalization of Technical and Operational Guidance Series (TOGS) documents.

On March 15, 2023, New York State Department of Environmental Conservation (NYSDEC) announced the issuance of final water quality guidance values to regulate Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonic acid (PFOS), and 1,4-Dioxane (1,4-D). The finalized guidance values support the State's ongoing efforts to protect public health and the environment and prevent exposure to emerging contaminants through the protection of drinking water sources. Additionally, the new guidance values for PFOS and 1, 4-Dioxane also provide protection for aquatic life.

The new GVs are established in an addendum to TOGS 1.1.1: Ambient Water Quality Standards and Guidance Values and Groundwater Effluent Limitations (PDF). 1 The TOGS 1.1.1 addendum is supplemented by the finalized revision to TOGS 1.3.7: Analytical Detectability and Quantitation Guidelines for Environmental Parameters (PDF) and a new TOGS 1.3.13: Permitting Strategy for Implementing Guidance Values for PFOA, PFOS, and 1,4-Dioxane (PDF).

TOGS 1.3.7 guides the selection of analytical testing methods in situations, such as when monitoring emerging contaminants, where methods approved by State and/or Federal oversight bodies are limited or unavailable. TOGS 1.3.13 establishes how the GVs for PFOA, PFOS, and 1,4-D are applied to State Pollutant Discharge Elimination System (SPDES) permits to optimize environmental protection and minimize financial impacts. In addition to the final guidance implementing actions to control industrial discharges, DEC is actually working on proposing draft guidance to address emerging contaminants discharged through Publicly Owned Treatment Works (POTWs).

In 2020, New York formally adopted among the nation's lowest maximum contaminated levels (MCLs) for drinking water for PFOA and PFOS at 10 parts per trillion (ppl)m and the first national standard for 1, 4-Dioxane at 1 part per billion (ppb). The MCLs were promulgated by the State's Drinking Water Quality Council, a body of water quality experts and scientists charged with setting limits in absence of federal standards for these emerging chemicals that have been pervasive in drinking water systems nationwide.

While MCLs adopted by the DOH provide protection for finished drinking water, DECs guidance values will provide complementary protection of ambient waters used as drinking water sources. The guidance values will initially be incorporated into requirements for industrial discharges needing a DEC State Pollutant Discharge Elimination System (SPDES) permit, so facilities do not contribute to harmful levels of emerging contaminants in the environment and these contaminants are appropriately controlled at industrial sources rather than downstream treatment systems.

The finalized GVs are shown in the table below. The DOH MCLs for finished drinking water are displayed for informational purposes.

Proposed Guidance Values
Chemical DOH - Finished Drinking Water DEC - Raw Water Source
Adopted MCLs Human Health Aquatic Life
Chronic Acute
PFOA 10 ppt 6.7 ppt N/A N/A
PFOS 10 ppt 2.7 ppt 160 ppb (fresh)
41 ppb (saline)
710 ppb (fresh)
190 ppb (saline)
1,4-Dioxane 1 ppb 0.35 ppb 18,000 ppb (fresh)
7,000 ppb (saline)
160,000 ppb (fresh)
63,000 ppb (saline)

The GVs were derived by procedures established in Title 6 of the New York Codes, Rules, and Regulations (NYCRR) Part 702.

DEC proposed draft guidance values for public review in October 2021 and conducted a thorough review of comments submitted and the latest information about the effects of emerging contaminants in surface waters. Summarized comments and NYSDEC's response can be reviewed in the Assessment of Public Comment document linked below. No substantial changes from the draft documents to the final documents have been made.

Available Documents

Linked below are the finalized TOGS documents and Assessment of Public Comments. Also provided are the facts sheets detailing the derivation of the GVs.

1 TOGS 1.1.1 was last issued in June 1998, with addenda in 2000 and 2004 to add protection for specific chemicals. TOGS 1.1.1 is the DOW's mechanism to establish guidance values.

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