The uptake of metabolites of permethrin by plants grown in soil treated with [14C]permethrin

Sugar beet, wheat, lettuce and cotton were grown in soil treated with [¹⁴C]permethrin, the crops being sown at intervals of 30, 60 and 120 days after treatment of the soil. The uptake of radioactive residues into these crops was measured. Low radioactive residues (up to 0.86 μg g^?1) were detected in the mature plants sown 30 days after soil treatment, and this uptake declined significantly as the interval between soil treatment and sowing increased. Metabolites derived from the acid moiety of the permethrin molecule were shown to constitute the greater part of the residue transferring from the soil to the crops. (1RS)-cis- and (1RS)-trans-3-(2,2-dichlorovinyl)- 2,2-dimethylcyclopropanecarboxylic acid and 3-(2,2-dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid were identified as the major acidic metabolites. The latter compound is a metabolite of permethrin which has not previously been identified in soil or plants.