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Persistence in Earthworms and Potential Hazards to Birds of Soil Applied DDT, Dieldrin and Heptachlor
W. Nelson Beyer and Charles D. Gish
Journal of Applied Ecology
Vol. 17, No. 2 (Aug., 1980), pp. 295-307
Published by: British Ecological Society
Stable URL: http://www.jstor.org/stable/2402326
Page Count: 13
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(1) DDT, dieldrin, and heptachlor were each applied to separate replicate plots in a hay field at 0$\cdot$6, 2$\cdot$2, or 9$\cdot$0 kg/ha. For 11 yr thereafter, soil and earthworms were analysed for residues. (2) The average ratios of residues in earthworms (dry weight) to residues in soil (dry weight) were: total DDT, 5; dieldrin, 8; and heptachlor epoxide, 10. The average time for the initial residues in soil to be reduced by 50% were: total DDT, 3$\cdot$2 yr; dieldrin, 5$\cdot$1 yr; and heptachlor epoxide, 3$\cdot$2 yr. The corresponding times for residues in earthworms were: total DDT, 3$\cdot$2 yr; dieldrin, 2$\cdot$6 yr; and heptachlor epoxide, 3$\cdot$0 yr. (3) DDE was most persistent, and in plots treated at 9$\cdot$0 kg/ha its concentration remained constant at about 0$\cdot$4 ppm in soil and about 7 ppm in earthworms. (4) When applied at 9$\cdot$0 kg/ha, DDT accumulated in earthworms to concentrations (32 ppm) which laboratory studies have shown to be hazardous to some sensitive bird species. When heptachlor was applied at 2$\cdot$2 or 9$\cdot$0 kg/ha, heptachlor epoxide in earthworms reached concentrations (8 ppm) potentially hazardous to woodcock. Dieldrin remained at potentially hazardous concentrations (8 ppm) for 3 yr in plots treated with 2$\cdot$2 kg/ha and for 11 yr in plots treated with 9$\cdot$0 kg/ha.
Journal of Applied Ecology © 1980 British Ecological Society