Organochlorine insecticide residues in surface and underground water from different regions of Bangladesh

The use of organochlorine insecticides (except heptachlor) for all agricultural and public health purposes was banned in Bangladesh by late 1993, although stocks could be used after that time and emergency use of limited quantities of DDT for plague control was permitted in 1994. Water samples from the different regions of Bangladesh were studied for organochlorine insecticide residues (OCs) during 1992-1995, both before and after the banning of the use of OCs. Packed column gas chromatographic (Electron Capture Detector mode) techniques were used and recovery was checked by monitoring the extraction of radio-labelled compounds with a Liquid Scintillation Counter. The results indicate slight contamination of some of the water samples of both surface and underground sources with residues of DDT, heptachlor, lindane and dieldrin. The majority of the samples, were found to be free from residues. Although use of heptachlor is allowed for specific purposes, its presence in surface water and ground water at levels well above WHO-recommended limits is a matter of concern. Appropriate remedial measures and systematic surveillance of heptachlor and other OC residues in water resources of the country are necessary to check further aggravation of the situation. (C) 1998 Elsevier Science B.V. All rights reserved.