Research Product

Technical-grade heptachlor (65% heptachlor, 22% trans-chlordane, 2% cis -chlordane, and 2% nonachlor) was tested in 96-hr bioassays to determine its toxicity to estuarine animals. The test organisms and the 96-hr LC50 or EC50s (based on measured concentrations in water) are as follows: American oyster (Crassostrea virginica), 1.5 µg/liter; pink shrimp (Penaeus duorarum), 0.11 µg/ liter; grass shrimp (Palaemonetes vulgaris), 1.06 µg/liter; sheepshead minnow (Cyprinodon variegatus), 3.68 µg/liter; pinfish (Lagodon rhomboides), 3.77 µg/ liter; and spot (Leiostomus xanthurus), 0.85 µg/liter. Analytical-grade heptachlor (99.8% heptachlor) and heptachlor epoxide (99%) were also studied. The analytical-grade heptachlor 96-hr LC50 for pink shrimp and spot was 0.03 µg/ liter and 0.86 µg/liter, respectively, while that for pink shrimp exposed to heptachlor epoxide was 0.04 µg/liter. Heptachlor was accumulated and some metabolized to its epoxide by all animals tested. Fish and oysters accumulated heptachlor in their tissues 2,800-21,300 times the measured concentration in water; shrimp, only 200-700 times.