Why is Oregon updating their water quality standards for copper?

Associated Oregon Industries
Oregon’s largest business advocate

Why is Oregon updating their water quality standards for copper?

The Oregon Department of Environmental Quality (ODEQ) recently announced the initiation of a rulemaking to revise its freshwater aquatic life criteria for copper. This rule (http://www.deq.state.or.us/wq/standards/copper.htm) is significant because aquatic life criteria:

Set the allowable concentration of chemicals for protection of aquatic life and their uses in water quality standards. These standards are then used for Clean Water Act discharge permit limits under the National Pollutant Discharge Elimination System (NPDES) program.
Determine whether waterbodies are considered “impaired” under the 303(d) program, in which case evaluation of Total Maximum Daily Loads (TMDLs) and development of pollution reduction plans may be required.

Any AOI member companies with facilities that have freshwater copper discharge effluent limitations in their NPDES permits may be affected by these changes. Changes to the copper freshwater aquatic life criteria could also potentially result in new effluent limitations where there currently are none.

The ODEQ rulemaking was initiated as the result of the U.S. Environmental Protection Agency’s (USEPA’s) January 2013 disapproval of Oregon’s copper criteria. The Oregon criteria were adopted by the Oregon Environmental Quality Control Commission (EQC) in 2004. Consistent with most states, Oregon’s 2004 criteria were derived solely on the basis of water hardness because copper – like many metals – is less toxic in waters of increasing hardness.

In large part, USEPA’s disapproval of Oregon’s 2004 criteria was triggered by two events:

1. An Endangered Species Act (ESA) consultation by the National Marine Fisheries Service (NMFS) on the 2004 criteria concluded that the hardness-based criteria would jeopardize the continued existence of ESA-listed fish (particularly such as salmon and trout), and

2. The 2004 criteria did not consider USEPA’s most recent (2007) recommended national ambient water quality criteria for copper which recommends that the criteria derive from the use of the “Biotic Ligand Model” (BLM) instead of the older hardness-based method.

As a result, ODEQ has stated their intention to base their revised freshwater copper criteria on the BLM, rather than hardness.

How did the BLM come about, what does it mean for aquatic life, and who is adopting the BLM?

The USEPA first published its recommended national criteria for copper in 1984. The criteria started as a mathematical equation that adjusted criteria concentrations only on the basis of water hardness. Criteria concentrations increased (i.e., became less restrictive) with increasing hardness. Hardness is a common measure of the combined concentrations of calcium and magnesium.

Since 1984, substantial scientific research has concluded that water quality characteristics other than hardness (pH, dissolved organic carbon [DOC], and other common chemical constituents of water) strongly alter the toxicity of copper to aquatic organisms. Research also found that the toxicity of copper to aquatic organisms could best be expressed on the basis of how much metal could chemically bind to the surfaces of an organism, collectively known as the “biotic ligand.” For fish, the best example of a biotic ligand is the gills because copper will bind to gill tissues and the amount of binding copper equates to a level of toxicity. The BLM accounts for the influence of all the critical water quality characteristics, including copper, and what copper levels will not negatively impact fish and other organisms.

The BLM has improved the accuracy of gauging copper toxicity in water samples. Understanding water hardness alone presented an incomplete picture, and so regulatory criteria derived on the basis of hardness are now known to be under-protective in some waters, and overprotective in other waters.

Since the publication of the USEPA national criteria in 2007, 18 states have formally adopted the freshwater copper BLM into their water quality standards programs. Most of these states only recommend using the BLM for derivation of site-specific water quality standards, but two states (Kansas and Delaware) recently adopted the BLM as a full, state-wide replacement for the older hardness-based standards. At least 16 other states are actively considering adopting the BLM.

Will the BLM benefit Oregon’s regulated community?

The answer to this question largely depends on the extent to which criteria derived using the BLM will be lower or higher than the hardness-based criteria used in the determination of reasonable potential and subsequent derivation of existing permitted effluent limitations for a facility. This ultimately depends on the chemical characteristics of a facility’s receiving water for constituents other than hardness.

For the most part, the BLM will benefit Oregon’s regulated community because for the majority of surface waters, copper criteria derived using the BLM will be higher than hardness-based criteria. This is largely due to the fact that the BLM incorporates the protective effects of DOC in the water. DOC chemically binds up copper, making copper far less toxic to aquatic life. Many natural forms of DOC exist in surface waters such as humic and fulvic acids. Municipal wastewater treatment plants can also discharge significant amounts of DOC.

However, in soft waters of relatively low pH (i.e., of pH 7 or less) and less DOC, BLM-based aquatic life criteria for copper can be significantly lower than hardness-based criteria. In Oregon, analyses suggest that BLM-based criteria will be lower than current hardness-based criteria in a relatively high percentage of waters in the Willamette Valley and Coastal regions. Therefore, AOI members having facilities with regulated copper discharges in those regions may be in a more challenging regulatory position as the result of the BLM.
What are the next steps in the process?

ODEQ formally initiated its rulemaking process for freshwater copper criteria at the end of April, 2015. Unlike most states that have chosen a site-specific approach, ODEQ plans to fully replace the old hardness-based criteria with the BLM on a statewide basis, possibly with regionally-specific BLM criteria. Few precedents exist for applying the model on a state-wide basis, so the application is a challenging one. Therefore, ODEQ’s process could end up breaking significant new ground in the development of regulatory copper criteria on a statewide basis using the BLM.

According to ODEQ’s website, the following steps and general timelines are expected:

– June-July 2015: Release BLM criteria calculations for Oregon’s surface waters and implementation procedures for outside peer review. This review should include ODEQ’s analysis of existing water quality data throughout the state, and what this means for ODEQ’s plans to use the BLM to derive copper criteria.
– August 2015 – January 2016: Advisory Committee meetings.
– May 2016 – June 29, 2016: Public comment period and hearings.
– October 19, 2016: Environmental Quality Commission meeting.
– November 2016: Submission to USEPA for approval.
– March 2017 (estimated): USEPA final action.

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