Odipo Osano,^* Daniel Nzyuko,^** Mwakio Tole,^*** Wim Admiraal<sup>****


*</sup>Odipo Osano, PhD, is a scientist at Moi University. He submitted his PhD thesis at the University of Amsterdam. His main interest is in the ecotoxicology of the pesticide degradation products on aquatic organisms. His address: Department of Aquatic Ecology and Ecotoxicology, IBED, University of Amsterdam. P.O. Box 94084, 1090 GB, Amsterdam, The Netherlands. odipo@africaonline.co.ke
^**Daniel Nzyuko, MSc, is a research scientist with interest in pollution of the aquatic environment with organic contaminants. His address: School of Environmental Studies, Moi University, P.O. Box 3900, Eldoret, Kenya. nzyukodm@yahoo.com
^***Peter Mwakio Tole, is a professor at the School of Environmental Studies, Moi University, Kenya. He is affiliated to the United Nations University. His research focuses on analyses of mineral contaminants in the environment. His current address: School of Environmental Studies, Moi University, P.O. Box 3900, Eldoret, Kenya. tole@kenyaweb.com
^****Wim Admiraal, PhD, is a professor at the University of Amsterdam, Faculty of Sciences. His research focuses on the ecology of benthic communities and on the interactions of biota with toxicants. His address: Department of Aquatic Ecology and Ecotoxicology, IBED, University of Amsterdam, P.O. Box 94084, 1090 GB, Amsterdam, The Netherlands. admiraal@science.uva.nl