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Long-term persistence of dieldrin, DDT, and heptachlor epoxide in earthworms

Ambio

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Abstract

Earthworms can accumulate persistent soilborne insecticides and are an important source of contamination of terrestrail wildlife. We treated experimental plots once with dieldrin, DDT, or heptachlor, and measured changes in insecticide concentrations in earthworms over a 20-year period. We estimated 'half-times,' defined as the time for a concentration in earthworms to be reduced by half. Deldrin had a half-time of 5.4 years. DDE, the metabolite of DDT most important to wildlife, increased until the third year and then decreased with a half-time of 5.7 years. Heptachlor epoxide, the metabolite of hepatachlor most important to wildlife, increased until the second year and then decreased with a half-time of 4.3 years. The declining parts of the curves of all three compounds fit exponential decay equations reasonably well. The estimates persistence are relevant to insecticides at low or moderate concentrations in relatively undistrubed soils in temperate climates.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Long-term persistence of dieldrin, DDT, and heptachlor epoxide in earthworms
Series title:
Ambio
Volume
18
Issue:
5
Year Published:
1989
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
271-273
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Ambio
First page:
271
Last page:
273
Number of Pages:
3