Document ID: EPA-HQ-OW-2015-0174-1021
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2020-07-21T04:00Z

Comparison of EPA November 2016 Partial Disapproval to the 2019 Proposed Reversal of the Disapproval to Approval
                                  May 8, 2019
The table below compares the key issues and rationale associated with the EPA's November 2016 partial disapproval of WA's human health criteria and the basis for the reversal of that decision. The purpose of this document is to fully inform the RA of the policy changes prior to signing a decision to reverse the partial disapproval.
                                     Issue
                     November 15, 2016 Partial Disapproval
               2019 Proposed Reversal of Disapproval to Approval
Summary of Change from Disapproval to Approval 
EPA disapproved 144 human health criteria based on an evaluation of Washington's submitted criteria against criteria that the EPA determined would be protective of the state's designated uses and scientifically defensible, based on EPA's 2015 304(a) human health criteria recommendation reflecting the latest scientific information and EPA policies. EPA's conclusion that Washington's criteria were not scientifically defensible were based on consideration of three criteria inputs: (1) appropriate bioaccumulation factors (BAFs), (2) protective relative source contribution (RSC) values between 0.2 and 0.8, and (3) a chemical-specific cancer risk level for PCBs that did not adequately protect tribal subsistence fishers. 

Based on CWA section 510 that allows states to adopt more stringent standards than otherwise required by the CWA, EPA approved Washington's submitted criteria that were more stringent than the criteria EPA determined to be protective.  
 
EPA is now reversing the November 2016 disapproval for all criteria except arsenic to an approval for the majority of criteria. EPA is also approving four criteria for two pollutants (thallium and 2,3,7,8-TCDD (dioxin)) that the agency previously deferred action on in November 2016.

The EPA now finds that Ecology's previously disapproved HHC are based on sound science and are protective of the State's designated uses, and is reversing the disapproval to an approval. In making this decision, the EPA considers that: 1) the CWA designates states as the primary authority for setting water quality standards; 2) the CWA envisions that states and authorized tribes will use their expertise and discretion in making resource- and risk-management decisions related to the protection of human health; 3) the 304(a) criteria are recommendations, not national mandates; 4) Ecology's 2016 HHC submittal included rationale sufficient to depart from the 304(a) national HHC recommendations and EPA should have deferred to Ecology and not subsituted its judgment for the State's resource- and risk-management decisions; and 5) Ecology's regulatory processes were several years underway by the time the EPA finalized its updated national 304(a) recommendations in June 2015 and the CWA envisions the triennial review process as an opportunity for states to review and modify as appropriate their WQS based on the latest science and information.
Bioaccumulation Factors (BAFs) versus Bioconcentration Factors (BCFs)
Washington submitted criteria derived using BCFs which account for contaminant uptake only from the water column. EPA's 2000 Human Health Methodology recommends the use of BAFs that account for uptake of a contaminant from all sources by fish and shellfish. The EPA's 2015 304(a) recommendations replace BCFs with BAFs, where data are available. The EPA's national recommended BAFs are based on peer-reviewed, publicly available data and were developed consistent with the EPA's 2000 Human Health Methodology and its supporting documents. Ecology did not demonstrate how its selection of outdated BCFs to derive human health criteria is scientifically defensible and protective of the applicable designated uses.  
Ecology's submittal correctly explains that no single input into the HHC equations determines the degree of protection provided by the calculated numeric criteria. Rather, the protectiveness of the criteria must be evaluated based on the suite of risk-management decisions, the totality of the inputs into the equations, and the resulting numeric criteria. Upon reconsideration, the EPA concludes that the BCFs utilized by Ecology are pollutant-specific, are consistent with the BCFs recommended by EPA in prior national CWA § 304(a) HHC recommendations, and together with the other inputs into the HHC equations result in water quality criteria that are based on sound science and protective of the state's designated uses, consistent with the rationale provided in Ecology's submittal.
Relative Source Contribution (RSC)

Ecology derived human health criteria using a RSC value of 1. Ecology stated that this is an appropriate risk management decision due to the limited ability of the CWA to control exposure to pollutant sources outside of its jurisdiction. The EPA recommends a RSC ceiling of 0.8 to ensure protection of individuals whose exposure could be greater than indicated by current data and to account for unknown sources of exposure. In the EPA's 2015 updated 304(a) recommendations and final federal rule for Washington, the EPA applied a pollutant-specific RSC value for all non-carcinogens and nonlinear carcinogens. 
The EPA agreed with Washington's inclusion of anadromous fish, which spend significant portions of their lives in marine waters, in the fish consumption rate (FCR). However, even when accounting for anadromous fish in the FCR, Washington did not adequately justify departing from the EPA guidance (to use a RSC between 0.2 and 0.8), nor did it adequately explain why it is appropriate to disregard all other routes of exposure including air, soil, other marine fish, shellfish, non-fish food consumption etc. The EPA concluded that "Ecology did not demonstrate how its selection of a RSC value of 1 to derive human health criteria is scientifically defensible and protective of the applicable designated uses."  
Upon reconsideration, the EPA should have evaluated the use of the RSC in context with the overall HHC package. Although the partial disapproval referenced the compelling need for the RSC identified in its 304(a) recommendation, the EPA did not identify a compelling need for that conservative measure in Washington, especially given the other conservative elements Ecology used to derive its HHC, including the FCR of 175 g/day or the cancer risk level of 10[-6]. 

The EPA now concludes that Ecology's use of an RSC of 1, coupled with other more conservative inputs in the HHC equations, appropriately balanced risks and resulted in HHC that are based on sound science and are protective of Washington's designated uses, consistent with the rationale provided in Ecology's submittal.

PCBs and Cancer Risk Level
Ecology elected to use a cancer risk level of 4 x 10[-5] for PCBs, consistent with the level of risk/hazard used by the Washington Department of Health in developing fish advisories. When Ecology used the 4 x 10[-5] cancer risk level along with its other inputs to calculate PCB criteria, the resulting criteria of 0.00029 ug/L were less stringent than the 1999 NTR values. Ecology then adjusted the cancer risk level to 2.3 x 10[-5] so the criteria adopted by the state would be equivalent to the national toxic rule criteria for PCBs, 0.00017 ug/L. 

The EPA determined that Washington's criteria of 0.00017 ug/L are not protective of Washington's designated uses. Ecology did not provide adequate supporting information or analysis to demonstrate that the criteria account for both consumption of water and consumption of organisms as exposure pathways for PCBs and are based on sound science. In addition, Ecology did not provide adequate justification for using the Washington Department of Health cancer risk level for this specific chemical and then adjusting that cancer risk level so that the criteria would be equivalent to the NTR criteria. Finally, Ecology did not demonstrate how the criteria were protective of applicable designated uses, including the tribal subsistence fishing portion of the fish and shellfish harvesting use as informed by treaty-reserved fishing rights. 
Upon reconsideration, the EPA concludes the chemical-specific cancer risk rate of 2.3x10-5 falls within the range of protective risk rates the EPA has recommended since it issued its 2000 Methodology and is protective of the State's designated uses, consistent with the rationale provided in Ecology's submittal. Nothing in the CWA prevents or prohibits a state from adopting a chemical-specific cancer risk rate, as long as the derived criteria are based on sound scientific rationale and protective of the designated use. 

As discussed further below, the EPA has also reconsidered its reliance on tribal treaty rights as a rationale for disapproving Ecology's HHC for PCBs.   

Tribal Treaty Rights
In determining whether WQS satisfy the CWA and the EPA's regulations, and when setting criteria for the protection of human health, it is necessary to consider other applicable laws, such as federal treaties (e.g., U.S. Treaties with Indians). Section 511 of the CWA provides that the Act "shall not be construed...as affecting or impairing the provisions of any treaty of the United States." While treaties do not expand EPA's authority, they are federal law binding on the federal government. Relevant case law, including Supreme Court precedents, unequivocally confirms that the treaty-reserved right to take fish includes the right to take fish for subsistence purposes. 

EPA concludes that the purpose for which tribes reserved such fishing rights through treaties has important implications for water quality regulation under the CWA. Fundamentally, the tribes' ability to take fish for their subsistence purposes under the treaties would be substantially affected or impaired if it were not supported by water quality sufficient under the CWA to ensure that tribal members can safely eat the fish for their own subsistence.

As a result, EPA has an obligation to ensure that its actions do not conflict with tribal treaty rights. It is therefore necessary and appropriate to consider tribal treaties to ensure that EPA's actions under the CWA are in harmony with such treaties. 

(via reference in the 11/15/16 partial disapproval to the final federal rule)
First, the EPA's longstanding view, consistent with the 2000 Methodology, is that a state may consider tribes with reserved fishing rights to be highly exposed populations, rather than the target general population, in order to derive criteria, and that such consideration gives due effect to reserved fishing rights. Second, the EPA believes it is permissible under the Clean Water Act for a State to choose to protect tribal members at a cancer risk level of at minimum 10[-4], consistent with the EPA's 2000 Methodology and protection afforded to other highly exposed subpopulations.

While the reserved rights in these tribal treaties may be considered by the State and the EPA when setting and reviewing criteria, they do not expand the EPA's authority under the CWA. Likewise, these treaties do not limit or prohibit the EPA from taking an otherwise lawful action under the CWA. The treaties also do not dictate the use of any cancer risk level more stringent than 10[-4]. Washington's selection of a cancer risk level of 2.3 x 10[-5] and an FCR of 175 g/day for its PCB criteria is consistent with the EPA's 2000 Methodology and gives due effect to reserved treaty rights. Because there is no conflict between the tribal treaties at issue and Washington's decision to protect high consuming tribal members with PCB criteria based on a 2.3 x 10[-5] CRL and an FCR of 175 g/day, it was improper and unnecessary for the EPA to disapprove the State's PCB criteria in order to "harmonize" the treaties and the CWA.