HAR §11-54-4. "Chronic Toxicity" means the degree to which a pollutant, discharge, or water sample causes a long-term adverse impact to aquatic organisms, such as a reduction in growth or reproduction

The chronic toxicity of a discharge or receiving water is measured using the methods in section 11-54-10, unless other methods are specified by the director. "Dilution" means, for discharges through submerged outfalls, the average and minimum values calculated using the models in the EPA publication, Initial Mixing Characteristics of Municipal Ocean Discharges (EPA/600/3-85/073, November, 1985), or in the EPA publication, Expert System for Hydrodynamic Mixing Zone Analysis of Conventional and Toxic Submerged Single Port Discharges (Cormix 1) (EPA/600/3-90/012), February, 1990. "In-Stream Waste Concentration" (IWC) means the concentration of a toxicant in the receiving water, or for a discharge, the concentration of the effluent after minimum dilution authorized by the department. A discharge of one hundred divided by the minimum dilution is the IWC when the dilution is authorized by the director. A discharge of one hundred per cent effluent is the IWC when dilution is not authorized by the director. "No Observed Effect Concentration" (NOEC), means the highest per cent concentration of a discharge or water sample, in dilution water, which causes no observable adverse effect in a chronic toxicity test. For example, a NOEC of one hundred per cent indicates that an undiluted discharge or water sample causes no observable adverse effect to the organisms in a chronic toxicity test. 54-22 3435 图 §11-54-4 "Test of Significant Toxicity" (TST) means the alternative statistical method for analyzing and interpreting valid whole effluent toxicity test data as described in the EPA publications, National Pollutant Discharge Elimination System Test of Significant Toxicity Implementation Document, EPA 833-R-10-003 (June 2010), and National Pollutant Discharge Elimination System Test of Significant Toxicity Technical Document, EPA 833-R-10-004 (June 2010). (2) Narrative toxicity and human health standards. (A) Acute Toxicity Standards: All state waters shall be free from pollutants in concentrations which exceed the acute standards listed in Appendix E dated OCT 22 2021, entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter. All state waters shall also be free from acute toxicity as measured using the toxicity tests listed in section 11-54-10, or other methods specified by the director. (B) Chronic Toxicity Standards: All state waters shall be free from pollutants in concentrations which on average during any twenty-four-hour period exceed the chronic standards listed in Appendix E dated OCT 22 2021, entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter. All state waters shall also be free from chronic toxicity as measured using the toxicity tests listed in section 11-54-10, or other methods specified by the director. 54-23 3435 §11-54-4 (C) Human Health Standards: All state waters shall be free from pollutants in concentrations which, on average during any thirty-day period, exceed the "fish consumption" standards for non-carcinogens in Appendix E dated OCT 2 2 2021 , entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter. All state waters shall also be free from pollutants in concentrations, which on average during any twelve-month period, exceed the "fish consumption" standards for pollutants identified as carcinogens in Appendix E dated OCT 2 2 2021 , entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter. (3) The following are basic requirements applicable to discharges to state waters. These standards shall be enforced through effluent limitations or other conditions in discharge permits. The director may apply more stringent discharge requirements to any discharge if necessary to ensure compliance with all standards in Appendix E dated OCT 2 2 2021 , entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter. (A) Continuous discharges through submerged outfalls. (i) The No Observed Effect Concentration (NOEC), expressed as per cent effluent, of continuous discharges through submerged outfalls shall not be less than one hundred divided by the minimum dilution; or 54-24 3435 §11-54-4 (ii) The Test of Significant Toxicity (TST), as described in EPA 833-R-10-003 (June 2010) and EPA 833-R-10-004 (June 2010), shall be used to demonstrate no unacceptable level of chronic toxicity at the In-stream Waste Concentration (IWC). The chronic toxicity criterion is expressed using a regulatory management decision (b value) of 0.75 for chronic toxicity where, a 0.25 effect level (or more) at the IWC demonstrates an unacceptable level of chronic toxicity. (B) Continuous discharges through submerged outfalls shall not contain: (i) Pollutants in twenty-four-hour average concentrations greater than the values obtained by multiplying the minimum dilution by the standards for the prevention of chronic toxicity in Appendix E dated OCT 22 2021, entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter; (ii) Non-carcinogenic pollutants in thirty-day average concentrations greater than the values obtained by multiplying the minimum dilution by the standards for fish consumption in Appendix E dated OCT 22 2021, entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter; and (iii) Carcinogenic pollutants in twelve-month average concentrations greater than the values obtained 54-25 3435 MD §11-54-4 by multiplying the average dilution by the standards for fish consumption in Appendix E dated OCT 22 2021, entitled "Numeric Standards for Toxic Pollutants Applicable to All Waters", located at the end of this chapter. (C) Discharges without submerged outfalls. (i) The survival of test organisms in an undiluted acute toxicity test of any discharge shall not be less than eighty per cent; (ii) Compliance with the acute toxicity NPDES effluent limit is demonstrated by using the Test of Significant Toxicity (TST) as described in EPA 833-R-10-003 (June 2010) and EPA 833-R-10-004 (June 2010). The acute toxicity criterion is expressed using a regulatory management decision (b value) of 0.80 for acute toxicity test methods listed in 11-54-10, where, in an undiluted acute toxicity test, a 0.20 effect level (or more) at the IWC demonstrates an unacceptable level of acute toxicity; or (iii) The Test of Significant Toxicity (TST), as described in EPA 833-R- 10-003 (June 2010) and EPA 833-R- 10-004 (June 2010), shall be used to demonstrate no unacceptable level of chronic toxicity at the IWC. The chronic toxicity criterion is expressed using a regulatory management decision (b value) of 0.75 for chronic toxicity where, a 0.25 effect level (or more) at the IWC demonstrates an unacceptable level 54-26 3435