Uptake, metabolism and toxicity of terbufos in the earthworm (Lumbricus terrestris) exposed to counter®‐15G in artificial soils

Earthworms (Lumbricus terrestris) were exposed to COUNTER® 15G in artificial soils for 32 d in four treatment blocks Simulated rainfall and temperatures were used to approximate conditions during planting time in the U S corn belt Maximum mean uptake of terbufos was noted on the 8th d following pesticide treatment Terbufos sulfoxide uptake by earthworms was higher than terbufos uptake, and the concentration maximum was observed on day 16 post application Maximum concentrations of terbufos sulfone were detected in earthworm tissues on day 32 post application No significant earthworm mortality was observed on any single collection date, but temporal differences in mortalities were noted between control and treatment groups Total concentrations of terbufos and oxidative metabolites in L terrestris substantiate existing residue data from field investigations