The toxicity, bioconcentration, and persistence of the pesticides acephate, aldicarb, carbophenothion, DEF, EPN, ethoprop, methyl parathion, and phorate were determined for estuarine environments. Static acute toxicity tests were conducted to determine the 96-h EC50 values for algae, 48-h EC50 values for oyster larvae, and 96-h LC50 values for at least two crustacean and fish species. Flow-through acute toxicity tests, based on measured concentrations, were conducted to determine the 96-h LC50 values of the pesticides for at least two crustacean and fish species. In addition, Maximum Acceptable Toxicant Concentrations (MATC) were determined in life-cycle toxicity tests with mysid shrimp (Mysidopsis bahia) and sheepshead minnows (Cyprinodon variegatus), or in partial life-cycle tests with grass shrimp (Palaemonetes pugio). MATCs were estimated from embryo-juvenile toxicity tests with sheepshead minnows. Persistence studies on carbophenothion, DEF, EPN, methyl parathion, and phorate investigated processes in marine systems that contribute to those pesticides' disappearance. The relative importance of biological and nonbiological processes (including biodegradation, photolysis, hydrolysis, sediment/water partitioning, and volatility) were examined. Bioconcentration factors for fish or mollusks exposed to carbophenothion, EPN, ethoprop, and phorate were determined at steady state or after plus or minus 28-day exposures.

"EPA-600/4-81-041." "May 1981." Photocopy.