Factors influencing the toxicity of two pesticides on three lumbricid species in laboratory tests

In laboratory tests, comparable to the OECD-Earthworm test No. 207, some of the factors influencing the toxicity of pesticides to three earthworm species (Eisenia fetida, Lumbricus terrestris and Aporrectodea longa) were assessed. An insecticide (Parathion) and a herbicide (Amitrole-Diuron formulation) were used as examples. For the experiments a fractional factorial test design was applied, which allows for the determination of effects of single factors as well as synergistic and antagonistic effects. Factors selected included soil moisture, soil temperature, the soil type and the way of application of the pesticides. Each factor was assessed at two levels. Parathion caused behavioural changes on all species, but only in the case of L. terrestris biomass and reproduction were significantly reduced. Soil moisture especially influenced distinctly and species-specifically biomass and cocoon production. There was no evidence of any effects of the herbicide at all.