Residues of organochlorine insecticides in two lakes of Jaipur, India

Water samples from Jalmahal lake and Mahalon lake were analysed by gas chromatography and electron capture detection for aldrin, lindane, heptachlor, p,p'-DDE, p,p'-DDD and p,p'-DDT during June 1985-July 1986. Both lakes were contaminated with moderate to high levels of organochlorine insecticides. The average insecticide residues in Mahalon lake was 0.93-5.71 ug per litre and in Jalmahal lake 0.55-11.4 ug per litre. The concentrations of p,p'-DDT in Jalmahal (5.7 ug per litre) and Mahalon (6.25 ug per litre) lakes were higher than recommended limits (2 ug per litre) for the protection of aquatic life. Residues were highest in September and October and lowest in March. Aldrin residues were comparable to the permissible limit (1 ug per litre) and lindane was below the recommended limit (5 ug per litre).