The Department is updating its rules related to whole effluent toxicity testing. The rules affected include the acute and chronic toxicity definitions in Chapter 62-302 (Surface Water Standards); new language specifying permit compliance limits for whole effluent toxicity testing in Chapter 62-4 (Permits); and new language specifying whole effluent toxicity sampling and testing procedures in Chapter 62-620 (Wastewater Facility Activities and Permitting). The purpose of the proposed revisions and additions is to more closely match EPA requirements for whole effluent toxicity testing, and to clarify existing whole effluent toxicity test procedures.