Heptachlor: Toxicity to and uptake by several estuarine organisms

Abstract

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 EC₅₀ s (based on measured concentrations in water) are as follows: American oyster (Crassostrea virginica), 7.5 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.