Endpoint and test failure criteria for acute tests

The endpoint for routine acute WET testing and retesting is the LC50. Acute test failure is greater than or equal to 50% mortality to a test species, as specified in OAC 252:690-3-29. Statistical analysis must be consistent with the methods described in the documents referenced in OAC 252:690-3-29. Where a WET limit is established, it is expressed as an LC50 effluent concentration and must be greater than 100% (>100%).