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The article examines the organochlorine (OC) residues in fish and water samples from Lake Victoria, Uganda. Organochlorine pesticides are halogenated organic compounds classified as dichlorodiphenyl-ethanes, hexachlorocyclohexanes, cyclodienes, and chlorinated benzenes. It compares the levels of OC with some cited extraneous residue limits. The researchers have found variations in pesticide dynamics in the tropical and subtropical environment compared with a temperate environment. However, due to their bioaccumulation tendencies and their ubiquitous nature, resulting from global transport and redeposition, the use of OCs has global implications.

Organochlorine (OC) residues were analysed in 117 sediment samples collected from four bays of the Uganda side of Lake Victoria. The sediments were collected with a corer at a depth of 0-20 cm, and extracted for OC residues using a solid dispersion method. The extracts were cleaned using gel permeation chromatography and analysed for pesticide residues using a gas chromatograph (GC) equipped with an electron capture detector. The results were confirmed using a GC equipped with a mass spectrometer (MS). A total of 16 OC residues, most of them persistent organic pollutants (POPs) were identified and quantified. The OC residue levels were expressed on an oven dry weight (d.w.) basis. Endosulphan sulphate, in the range of 0.82-5.62 μg kg⁻¹ d.w., was the most frequently detected residue. Aldrin and dieldrin were in the ranges of 0.22-15.96 and 0.94-7.18 μg kg⁻¹ d.w., respectively. DDT and its metabolites lay between 0.11-3.59 for p,p'-DDE, 0.38-4.02 for p,p'-DDD, 0.04-1.46 for p,p'-DDT, 0.07-2.72 for o,p'-DDE and 0.01-1.63 μg kg⁻¹ d.w. for o,p'-DDT. The levels of γ-HCH varied from 0.05 to 5.48 μg kg⁻¹ d.w. Heptachlor was detected only once at a level of 0.81 μg kg⁻¹ d.w., while its photo-oxidation product, heptachlor epoxide, ranged between non-detectable (ND) to 3.19 μg kg⁻¹ d.w. Chlordane ranged from ND to 0.76 μg kg⁻¹ d.w. Based on the threshold effect concentration (TEC) for fresh water ecosystems, aldrin and dieldrin were the only OCs that seemed to be a threat to the lake environment., (Copyright © 2010 Elsevier Ltd. All rights reserved.)