Persistence and changes in bioavailability of dieldrin, DDE, and heptachlor epoxide in earthworms over 45 years.

W Nelson Beyer, Robert W Gale

Ambio 2013 Feb

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The finding of dieldrin (88 ng/g), DDE (52 ng/g), and heptachlor epoxide (19 ng/g) in earthworms from experimental plots after a single moderate application (9 kg/ha) 45 years earlier attests to the remarkable persistence of these compounds in soil and their continued uptake by soil organisms. Half-lives (with 95 % confidence intervals) in earthworms, estimated from exponential decay equations, were as follows: dieldrin 4.9 (4.3-5.7) years, DDE 5.3 (4.7-6.1) years, and heptachlor epoxide 4.3 (3.8-4.9) years. These half-lives were not significantly different from those estimated after 20 years. Concentration factors (dry weight earthworm tissue/dry weight soil) were initially high and decreased mainly during the first 11 years after application. By the end of the study, average concentration factors were 1.5 (dieldrin), 4.0 (DDE), and 1.8 (heptachlor epoxide), respectively.

Citation

W Nelson Beyer, Robert W Gale. Persistence and changes in bioavailability of dieldrin, DDE, and heptachlor epoxide in earthworms over 45 years. Ambio. 2013 Feb;42(1):83-9