ABSTRACT
The cyanopyrethroid insecticide, cypermethrin, is widely used in the control of a variety of insect pests. It acts as nerve poison in the target organisms. The toxicity of cypermethrin has been investigated according to an artificial soil test procedure using Eisenia foetida. In the tests, the technical grade substances, Ripcord and Fastac were employed. Cypermethrin is accumulated by earthworms to different extents from the treated soils. The potential for accumulation and biotransformation were studied also in the earthworm species, Lumbricus terrestris and Allolobophora caliginosa. The level of bioconcentration, however, appears to be dependent both on the species and the substrate concentration. Laboratory and field observations indicate that this insecticide may not pose a hazard to either the population or the biomass of earthworms when used at the recommended rates. Earthworms biotransform cypermethrin to more than 90% within a short period of time.
