Contamination of stored food and feed commodities from indoor use of HCH and DDT in malaria control programmes

Samples of wheat grain, straw, flour and green fodder taken from houses sprayed with either HCH or DDT for mosquito control showed the presence of HCH residues at concentrations of up to 91.2, 208.8, 33.1 and 459.0 mg kg-1 and DDT residues up to 11.3, 86.1, 2.2 and 5.4 mg kg-1, respectively. The mean level of HCH residues in samples of wheat grain collected from randomly selected houses in areas sprayed with HCH for the control of malaria was approximately 8 times higher than that for corresponding samples from DDT sprayed areas. In contrast, DDT residues in wheat grain samples from the DDT sprayed area were 3 times higher than the samples from the HCH sprayed area. The results suggest that significant amounts of residues of HCH and DDT become transferred to commodities stored in houses sprayed with these insecticides for mosquito control.