Research Product

Laboratory toxicity tests were conducted to determine the effects and accumulations of Kepone in estuarine algae, mollusks, crustaceans, and fishes. Nominal Kepone concentrations calculated to decrease algal growth by 50% in static bioassays lasting seven days were: 350 µg/l, Chlorococcum sp.; 580 µg/l, Dunaliella tertiolecta; 600 µg/l, Nitzschia sp.; and 600 µg/l, Thalassiosira pseudonana. Measured Kepone concentrations calculated to cause 50% mortality in flowing-seawater toxicity tests lasting 96 hours were: 10 µg/l for the mysid shrimp (Mysidopsis bahia); 120 µg/l for the grass shrimp (Palaemonetes pugio); >210 µg/l for the blue crab (Callinectes sapidus); 70 µg/l for the sheepshead minnow (Cyprinodon variegatus); and 6.6 µg/l for the spot (Leiostomus xanthurus). Bioconcentration factors (concentration in whole animals divided by concentration measured in water) in these tests were greatest for fishes (950 to 1,900) and less for grass shrimp (420 to 930). Survival, growth, and reproduction of mysids and sheepshead minnows were decreased in chronic bioassays lasting 14 to 64 days. Growth of mysids and sheepshead minnows in the chronic bioassay averaged 5,200 (range, 3,100-7,000) for adults exposed for 28 days and 7,200 (3,600-20,000) for juveniles exposed for 36 days. The chronic toxicity and bioconcentration potential of Kepone are more important factors than its acute toxicity in laboratory evaluations of environmental hazard. Therefore, these factors should be considered when attempting to assess present impacts and to limit future impacts of this insecticide on the aquatic environment.