Title 40—Protection of Environment--Volume 1
PART 131—WATER QUALITY STANDARDS
§ 131.46   Aquatic life criterion for cadmium in Oregon.
(a) Scope. This section promulgates an acute aquatic life criterion for cadmium in freshwaters in Oregon.
(b) Criterion for cadmium in Oregon. The aquatic life criterion in Table 1 applies to all freshwaters in Oregon where fish and aquatic life are a designated use.
Table 1—Cadmium Aquatic Life Criterion for Oregon Freshwaters
1 The criterion for cadmium is expressed as the dissolved metal concentration.
2 CF is the conversion factor used to convert between the total recoverable and dissolved forms of cadmium. The term (ln hardness) in the CMC and the CF equation is the natural logarithm of the ambient hardness in mg/L (CaCO 3 ). The default hardness concentrations from the applicable ecoregion in Table 2 of paragraph (c) of this section shall be used to calculate cadmium criteria in the absence of sufficiently representative ambient hardness data.
3 The CMC is the highest allowable one-hour average instream concentration of cadmium. The CMC is not to be exceeded more than once every three years. The CMC is rounded to two significant figures.
(c) Estimated Values To Calculate Cadmium Criteria. The default inputs to calculate cadmium criteria in the absence of sufficiently representative ambient data are shown in Table 2.
Table 2—Hardness Defaults Within Each Level III Ecoregion in Oregon
(d) Applicability. (1) The criterion in paragraph (b) of this section applies to freshwaters in Oregon where fish and aquatic life are a designated use, and applies concurrently with other applicable water quality criteria.
(2) The criterion established in this section is subject to Oregon's general rules of applicability in the same way and to the same extent as are other federally promulgated and state-adopted numeric criteria when applied to freshwaters in Oregon where fish and aquatic life are a designated use.
(i) For all waters with mixing zone regulations or implementation procedures, the criterion applies at the appropriate locations within or at the boundary of the mixing zones and outside of the mixing zones; otherwise the criterion applies throughout the water body including at the end of any discharge pipe, conveyance or other discharge point within the water body.
(ii) The state shall not use a low flow value that is less stringent than the values listed below for waters suitable for the establishment of low flow return frequencies ( i.e., streams and rivers) when calculating the available dilution for the purposes of determining the need for and establishing Water Quality-Based Effluent Limitations in National Pollutant Discharge Elimination System permits:
§ 131.47   Aquatic life criteria for aluminum in Oregon.
(a) Scope. This section promulgates aquatic life criteria for aluminum in fresh waters in Oregon that are jurisdictional under the Clean Water Act.
(b) Criteria for aluminum in Oregon. The aquatic life criteria in Table 1 to this paragraph (b) apply to all fresh waters in Oregon that are jurisdictional under the Clean Water Act to protect the fish and aquatic life designated uses.
Table 1 to Paragraph (b) —Aluminum Aquatic Life Criteria for Oregon Fresh Waters
1 To apply the aluminum criteria for Clean Water Act purposes, criteria values based on ambient water chemistry conditions must protect the water body over the full range of water chemistry conditions, including during conditions when aluminum is most toxic.
2 These criteria are based on aluminum toxicity studies where aluminum was analyzed using total recoverable analytical methods. Oregon may utilize total recoverable analytical methods to implement the criteria. For characterizing ambient waters, Oregon may also utilize, as scientifically appropriate and as allowable by State and Federal regulations, analytical methods that measure the bioavailable fraction of aluminum ( e.g., utilizing a less aggressive initial acid digestion, such as to a pH of approximately 4 or lower, that includes the measurement of amorphous aluminum hydroxide yet minimizes the measurement of mineralized forms of aluminum such as aluminum silicates associated with suspended sediment particles or clays). Oregon shall use measurements of total recoverable aluminum where required by Federal regulations.
3 The CMC is the highest allowable one-hour average ambient concentration of aluminum. The CMC is not to be exceeded more than once every three years. The CMC is rounded to two significant figures.
4 The CCC is the highest allowable four-day average ambient concentration of aluminum. The CCC is not to be exceeded more than once every three years. The CCC is rounded to two significant figures.
5 EPA-822-R-18-001, Final Aquatic Life Ambient Water Quality Criteria for Aluminum—2018, December 2018, is incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. All approved material is available from U.S. Environmental Protection Agency, Office of Water, Health and Ecological Criteria Division (4304T), 1200 Pennsylvania Avenue, NW, Washington, DC 20460; telephone number: (202) 566-1143, www.epa.gov/wqc/aquatic-life-criteria-aluminum. It is also available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email fedreg.legal@nara.gov or go to www.archives.gov/federal-register/cfr/ibr-locations.html.
(c) Applicability. (1) The criteria in paragraph (b) of this section are the applicable acute and chronic aluminum aquatic life criteria in all fresh waters in Oregon that are jurisdictional under the Clean Water Act to protect the fish and aquatic life designated uses.
(2) The criteria established in this section are subject to Oregon's general rules of applicability in the same way and to the same extent as are other federally promulgated and state-adopted numeric criteria when applied to fresh waters in Oregon that are jurisdictional under the Clean Water Act to protect the fish and aquatic life designated uses.
(3) For all waters with mixing zone regulations or implementation procedures, the criteria apply at the appropriate locations within or at the boundary of the mixing zones and outside of the mixing zones; otherwise the criteria apply throughout the water body including at the end of any discharge pipe, conveyance, or other discharge point within the water body.