Persistence in earthworms and potential hazards to birds of soil applied DDT, dieldrin and heptachlor.

Published online
01 Jan 1980
Content type
Journal article
Journal title
Journal of Applied Ecology

Beyer, W. N. & Gish, C. D.

Publication language


DDT, dieldrin and heptachlor were applied to separate plots in a hay field at 0.6, 2.2 or 9.0 kg/ha. For 11 yr thereafter, soil and earthworms were analysed for residues. The average ratios of residues in earthworms (dry weight) to residues in soil (dry weight) were: total DDT, 5; dieldrin, 8; heptachlor epoxide, 10. The average time for the initial residues in soil to be reduced by 50% were: total DDT, 3.2 yr; dieldrin, 5.1 yr; heptachlor epoxide, 3.2 yr. The corresponding times for residues in earthworms were: total DDT, 3.2 yr; dieldrin, 2.6 yr; heptachlor epoxide, 3.0 yr. DDE was most persistent, and in plots treated at 9.0 kg/ha its concentration remained constant at about 0.4 ppm in soil and about 7 ppm in earthworms. When applied at 9.0 kg/ha, DDT accumulated in earthworms to concentrations (32 ppm) which are hazardous to some sensitive bird species. When heptachlor was applied at 2.2 or 9.0 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 2.2 kg/ha and for 11 yr in plots treated with 9.0 kg/ha.

Key words