Organochlorine insecticide residues in earthworms from arable soils

Six species of earthworms from an arable soil were analysed for residues of aldrin, dieldrin, DDT and γ‐BHC. The ratios between the concentrations of γ‐BHC, aldrin + dieldrin and p,p′‐DDT + p,p′‐DDE in the earthworms and in the soil (concentration factors) were similar but the residue concentrations were consistently higher in the smaller more shallow‐living species Allolobophora caliginosa, A. chlorotica and A. rosea than in the larger deeper‐living species Lumbricus terrestris, A. longa and Octolasion cyaneum. In arable field plots, dieldrin residues in A. longa and A. chlorotica increased with increasing concentrations in the soil but the concentration factors decreased. The concentrations of residues in earthworms (W) appear to be related to those in the soil (S) by an equation of the form W = aSb where a and b are constants, the latter being about 0.79 for a wide range of residue data embracing the uptake of aldrin‐dieldrin, DDT components, and γ‐BHC by earthworms.