Washington Administrative Code › Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508) › Chapter 173-205 - Whole effluent toxicity testing and limits › Section 173-205-050 - Effluent testing for toxicity

Current through Register Vol. 24-14, July 15, 2024
(1) The department shall require dischargers
			 meeting the risk definition of WAC
			 173-205-040(1) to characterize the effluent for toxicity during permit application or during
			 the first year of the permit term.
(a) Each
			 effluent sample during effluent characterization shall be tested for toxicity
			 using multiple species which shall at a minimum include a fish, an
			 invertebrate, and, if deemed appropriate by the department, a plant.
(b) The sampling frequency during effluent
			 characterization and compliance monitoring shall be at least twice per year and
			 sampling shall be timed to cover the seasonal extremes of the year such as
			 wet-dry or cold-hot.
(c) The
			 duration of an acute toxicity test performed for effluent characterization or
			 compliance monitoring shall be forty-eight hours for an invertebrate and
			 ninety-six hours for a fish.
(d)
			 For effluent characterization and compliance monitoring, the department shall
			 use toxicity tests published in  40 C.F.R. Part 136, in EPA toxicity test
			 manuals, or those methods approved by the department considering the following
			 criteria:
(i) The existence of a detailed
			 written description of the test method;
(ii) Interlaboratory comparisons of the
			 method;
(iii) Adequate testing with
			 complex wastes such as wastewater;
(iv) Measurement of an effect that is clearly
			 adverse to the production of the species such as reduced survival or growth,
			 abnormal development, or failed reproduction; and
(v) Use of test organisms that represent
			 taxonomic families native to the state.
(e) Toxicity testing for effluent
			 characterization under this section, compliance monitoring as described in WAC
			 173-205-070, and additional
			 monitoring as described in WAC
			 173-205-090 or
			 173-205-120(2)(d) shall be performed by laboratories
			 accredited by the department for the specific toxicity test in accordance with
			 chapter 173-50 WAC.
(f) Upon
			 request, the department may approve the performance of toxicity tests for
			 effluent characterization or compliance monitoring for publicly owned treatment
			 works discharging less than one-half million gallons per day and small
			 businesses as defined in RCW 43.31.025(4) as effluent screening tests using one
			 hundred percent effluent for the acute toxicity tests and the acute critical
			 effluent concentration for the chronic toxicity tests.
(i) If an acute one hundred percent effluent
			 screening test demonstrates less than eighty percent survival, the test shall
			 be repeated as soon as possible on a fresh sample using the full dilution
			 series test described in the permit or regulatory order.
(ii) The chronic screening tests shall be
			 expected to have no statistically significant difference in response between
			 the acute critical effluent concentration and the control using the method in
			 Appendix H of EPA/600/4-89/001 or an equivalent method approved by the
			 department, or the test shall be repeated as soon as possible on a fresh sample
			 using the full dilution series test described in the permit or regulatory
			 order. The chronic effluent screening tests shall also meet the chronic
			 statistical power standard.