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(66-06) Chloroacetanilides and their degradation products cause developmental disorders in frogs: implications for herbicide use in Kenya. Admiraal, Wim*,1, Osano, Odipo1,2, 1 University of Amsterdam, Dept. Aquatic Ecology and Ecotox. Kruislaan 320, Amsterdam, The Netherlands2 School of Environmental Studies, Moi University, P. O. Box 3900, Eldoret, Kenya ABSTRACT- Pesticides are known to transform in the environment, but so far the study of their effects in the environment has concentrated on the parent compounds thereby neglecting the effects of the degradation products. The embryotoxic, developmental and teratogenic effects of chloracetanilide herbicides and their environmentally stable aniline degradation products were investigated in this study in view of the massive application of alachlor and metolachlor. Embryos at midblastula to early gastrula stages of a locally abundant African clawed frog Xenopus laevis were used were exposed to the test chemicals for 96 h in experiments. Alachlor is more embryotoxic and teratogenic than metolachlor. The degradation products of alachlor and metolachlor, respectively, 2,6-diethylaniline and 2-ethyl-6-methyaniline are less embryotoxic but more teratogenic than their parent compounds. The anilines were detected in water and sediment of the R. Nzoia (Kenya) probably resulting from the massive application of alachlor and metolachlor as a herbicide in maize and sugar cane farms. The fate and indirect effects of these herbicides use are discussed to evaluate the potential risk for aquatic life. Key words: chloroacetanilides, teratogenicity, degradation products, Xenopus laevis |
