HCH and carbaryl residues in groundnut

Groundnut plants were treated with hexachlorocyclohexane (HCH) or 1-naphthyl-N-methylcarbamate (carbaryl) following agricultural practices and the residues were followed in seed and oil. In the oil extracted from kernels of HCH treated plants, β-isomer of HCH was present in greater amounts than other isomers. Commercial procedures like alkali refining and bleaching did not remove 14C radioactivity from 14Cα- or β- or γ-HCH fortified groundnut oil. Deodorisation procedure had removed 86% and 94% of α- and γ-HCH radioactivity. However with β-isomer only 56% 14C radioactivity was removed. Experiments with unlabelled and labelled carbaryl showed that in oil extracted from kernels of carbaryl treated plants, residues as carbaryl were not present. Alkali refining and bleaching had together removed 76% of total 14C radioactivity initially added. However, deodorisation procedures could remove only 23% of 14C radioactivity. The significance of the above results is discussed. (author)