DDT and HCH residues in basmati rice (Oryza sativa) cultivated in Dehradun (India)

Organochlorine pesticides were used earlier for agriculture production. Their residues may still be present in soil and may accumulate in food crops, posing potential health problems to consumers. DDT, HCH, their isomers and metabolites were analyzed in samples of soil and rice plants collected from ten different villages of a well-known Basmati rice growing area in Dehradun. Residues of both pesticides were found in all samples of soil and different parts of rice plants except for a few grain samples. Maximum residue was observed in husk and minimum in grains. The average concentration of DDT in soil ranged from 0.013 to 0.238 ppm. p,p'-DDE was the major metabolite (>63%). The average concentration of DDT in rice grain varied from 0.002 to 0.040 ppm. o,p'-DDT was the main isomer (>93%). The average concentration of HCH in soil ranged from 0.122 to 0.638 ppm. beta-HCH was the predominant (43%) isomer followed by alpha-HCH (21%). The average HCH concentration in rice grain ranged between 0.013 and 0.113 ppm. All four isomers were present in grains. The levels of DDT and CHC in grains were similar in magnitude as those from different Indian states, but well below the maximum residue limit of 0.1 ppm for DDT and 0.05 ppm for HCH prescribed by the Government of India and WHO/FAO. As such, the pesticide residue levels in this export commodity are not of hazardous nature.