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Water Quality Standards for Toxic Pollutants

Water quality standards are the foundation of the water quality-based control program mandated by the Clean Water Act. Water Quality Standards define the goals for surface waters in Oregon by designating its uses, setting criteria to protect those uses and establishing provisions to protect water quality from pollutants.

DEQ is responsible for establishing water quality criteria for toxic pollutants to protect both aquatic life and human health. These criteria are established to protect surface water for aquatic life use and to allow Oregonians to consume fish and shellfish and to use state waters for drinking water supply without adverse health effects. DEQ develops its water quality criteria based on EPA recommended criteria. 

Current Toxics Standards

Human Health and Aquatic Life Criteria Tables

Table Description
Human Health Criteria
Table 40 Effective human health criteria adopted by the EQC on June 16, 2011 and approved by EPA on Oct. 17, 2011
Aquatic Life Criteria
Effective criteria from Tables 20, 33A, and 33B Effective aquatic life criteria as a result of EPA approval and disapproval actions on Jan. 31, 2013
Table 33C Guidance values ONLY (not water quality criteria). 
EQC-adopted Tables 20, 33A, and 33B
EQC-adopted tables of aquatic life toxics criteria

(Note: While these tables represent the most recently adopted tables, readers should refer to Tables 20, 33A and 33B above for the effective criteria based on EPA's Jan. 31, 2013 action.)

Toxics Standards Rule (OAR 340-041-0033)

Human Health Toxics Criteria

On June 1, 2010, EPA disapproved the majority of the human health criteria adopted by the EQC in May 2004. EPA concluded that the criteria values were based on a fish consumption rate that was too low (17.5 grams/day) to protect many fish consumers in Oregon.  After an extensive review of the fish consumption rate, DEQ revised the human health toxics criteria based on a higher per capita fish consumption rate of 175 grams/day. These criteria are now incorporated into Table 40 and are effective under state and federal law for Clean Water Act programs. Table 40 criteria became effective following EQC adoption on June 16, 2011, and EPA approval on Oct. 17, 2011. EPA approved revisions to the manganese criteria and withdrawal of iron on June 9, 2011. These revisions are reflected in Table 40. 

Aquatic Life Toxics Criteria

EPA Takes Action on Oregon's Aquatic Life Criteria

On January 31, 2013, EPA took action on Oregon’s new or revised aquatic life toxics criteria submitted in 2004. These criteria are developed to protect aquatic species such as fish, shellfish, and aquatic insects. The aquatic life toxics criteria for each pollutant are typically comprised of four values: acute and chronic values for freshwater, and acute and chronic values for saltwater protection.

EPA approved 38 criteria associated with 14 toxic pollutants and disapproved 45 criteria values associated with 16 toxic pollutants (11 pesticides, ammonia, cadmium, copper, selenium, and aluminum). EPA disapproved the freshwater acute criterion for cadmium based on findings in the National Marine Fisheries Service’s August 2012 Biological Opinion. EPA disapproved the ammonia criteria because new toxicity data showed that the criteria were not protective of mollusks. EPA also disapproved criteria associated with 14 other pollutants, including 11 pesticides, copper, selenium and aluminum, due to inconsistencies associated with EPA’s nationally recommended criteria.

The criteria approved by EPA are now federally effective for Clean Water Act programs. When a standard submitted to EPA by the state is disapproved by EPA, the previously effective standard remains in effect for federal Clean Water Act purposes (i.e. criteria in Table 20). For a list of currently effective criteria, see Tables 20, 33A, and 33B above.

DEQ has initiated a new rulemaking to correct a number of errors related to the toxics water quality standards regulations. Some of these errors are related to EPA’s action on the aquatic life criteria described above, while other errors and clarifications are related to the human health criteria for toxics. See the Corrections and Clarifications to Toxics Water Quality Standards Rulemaking website for more information.

Calculator for Freshwater Hardness-Dependent Metals Criteria
The toxicity of a metal to an aquatic organism can vary based on many different factors, including the route of exposure to the metal, the type and form of the metal and the physical and chemical characteristics of the water where the exposure takes place. Oregon’s aquatic life criteria for certain metals are based on water hardness. Generally, as hardness increases, the toxicity of metals decreases. The calculator below provides calculated acute and chronic criteria for certain metals based on the hardness of the water.

Metals Criteria Calculator

Calculator for Freshwater and Saltwater Ammonia Criteria
The chemical form of ammonia in water consists of two species—ammonium (NH4+) and unionized ammonia (NH3). The more toxic form of ammonia to aquatic life is unionized ammonia. The ratio of these species in water is dependent upon both pH and temperature. Generally, as pH and temperature increase, the unionized, more toxic form of ammonia increases. Consequently, the ammonia criteria become more stringent. The calculator below provides calculated acute and chronic criteria based on the pH and temperature of water, and the presence or absence of salmonids or other sensitive coldwater species. Oregon’s effective freshwater acute and chronic criteria are based on equations from EPA’s 1985 304(a) ammonia criteria recommendations. The effective saltwater ammonia criteria are based on EPA’s 1989 304(a) recommendations. The final values in the calculator reflect the conversion of unionized ammonia to total ammonia nitrogen.

Ammonia Criteria Calculator

Recommendations for Analysis and Implementation of Specific Toxic Pollutants

Below is a list of memos that describe analytical methods for specific pollutants, including associated implementation and monitoring considerations. DEQ developed these memos to provide guidance to DEQ staff and other interested members of the public in response to analytical questions that have been raised on specific water quality toxics criteria. Additional memos may be posted here as other questions arise. Note that the Quantitation Limits for NPDES Permitting IMD referenced in the memos is not yet final. Once final, a link to that guidance document will be provided. In the interim, the most current quantitation limits for toxic pollutants may be found in the NPDES Permit Template document

Other Information

Fact Sheet: Mercury in Oregon Waters NEW

Related Links

Department of Environmental Quality

Oregon Health Authority

Washington Department of Ecology

US Environmental Protection Agency



Please contact Andrea Matzke at Oregon DEQ, 503-229-5384 or by email for additional information.

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For more information on DEQ's Water Quality Division and its programs, see our contact page.

Oregon Department of Environmental Quality
Headquarters: 811 SW Sixth Ave., Portland, OR 97204-1390
Phone: 503-229-5696 or toll free in Oregon 1-800-452-4011
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