Aluminum Criteria Revisions Water Quality Standards Triennial Review 2019 – 2020 Workgroup Meeting 6 August 2019 Robert Henige
Why Update Aluminum Criteria? • More accurate knowledge on toxicity of aluminum • Uses 3 site parameters and multiple linear regression to normalize toxicity • No longer over or under protective
Rulemaking History In Missouri • Missouri’s current water quality criteria for aluminum were approved by EPA in September 2000 and are based upon EPA’s “Ambient Water Quality Criteria for Aluminum, 1988”.
EPA Recommendation
EPA Calculator • Aluminum Criteria Calculator V.2.0xlsx – Takes into account pH, DOC, and total hardness – Easy to use – Very adaptable and concise
EPA Calculator Cont. 1 of 22 different species used to develop equations Normalized equations
Recommended Revisions to 10 CSR 20-7.031 • 5 Changes Located at: – 1(A) Definitions – 5(A) Specific Criteria – 5(B)2.A. Aquatic Life Protection and Human Health Protection – 5(B)8 – Table A.1
Revisions Cont. • 1(A) and 5(A) adding “…and is not to be exceeded more than once every three years. …” • 5(B)2.A. Changing Aluminum from dissolved to total recoverable • Adding condition 5(B) 8. which is incorporation by reference of the EPA Final Aquatic Life Ambient Water Quality Criteria for Aluminum 2018
Revisions Cont. • Table A1:
Implementation These numbers are not a part of the rule
Example Permit Limits for Using Default Parameters Permit Limits in μ g/L Ecoregion Current Aluminum Criteria Proposed Aluminum Criteria Acute Limit Chronic Limit Acute Limit Chronic Limit Central Irregular Plains 1314.1 655 Interior River Valleys and Hills 1149.9 573.2 Mississippi 750 373.8 Alluvial Plain 1182.7 589.5 Ozark Highlands 1330.6 663.2 Western Corn Belt plains 1560.5 777.9 Unclassified 1806.9 900.7
Questions? Robert Henige Robert.Henige@dnr.mo.gov 573-526-1535
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