Pesticide residues in foodstuffs in Great Britain. IX.—Aldrin, dieldrin and other organochlorine pesticide residues in potatoes and carrots

Abstract Potatoes from 186 commercial crops from fields treated with aldrin or dieldrin in the year of cropping contained mean residues of aldrin plus dieldrin of 0.01 ppm in the flesh and 0.1 ppm in the skin. Seventy crops from fields that had been treated with aldrin or dieldrin in years previous to the year of cropping and forty‐four crops from reputedly untreated fields contained mean residues of aldrin/dieldrin of less than 0.01 ppm in the flesh and 0.02 ppm in the skin. Alpha‐ and/or gamma‐BHC were detected in trace or greater amounts in 73% and pp' DDE in 10% of the samples. Carrots from 97 commercial crops from fields treated with aldrin or dieldrin in the year of cropping contained mean residues of aldrin plus dieldrin of less than 0.01 ppm in the flesh and 0.21 ppm in the skin. Fifty crops from fields that had been treated with aldrin or dieldrin in years previous to the year of cropping contained mean residues of aldrin/dieldrin of less than 0.01 ppm in the flesh and 0.07 ppm in the skin. Six crops from reputedly untreated fields contained a mean residue of less than 0.01 ppm dieldrin in the skin only. Alpha‐ and gamma‐BHC were found in the majority of the samples (mean total residue of less than 0.01 ppm in the flesh and 0.03 ppm in the skin) but pp' DDE and/or pp' DDT were detected in only 12% of the samples.