DDT AND OTHER INSECTICIDES IN THE LAKE KARIBA ECOSYSTEM, ZIMBABWE

Although DDT and other persistent pesticides are now banned in most industrialized countries, they are still used or have only recently been discontinued in many developing countries. Organochlorine pesticides, mainly DDT and metabolites were analyzed in fish, mussels, prawns and birds from different localities and trophic levels and are compared to two other Zimbabwean man-made lakes. sDDT seemed to be both bioaccumulating and biomagnifying and levels were generally relatively high, but did not differ much from temperate lakes. The algae feeder, Redbreast Tilapia (Tilapia rendalli), had 1900 ng sDDT . g-1 fat, while the levels in the predatory tigerfish (Hydrocynus forskahlii) were 5000 ng sDDT . g-1 fat. The highest levels were found in bottom living species, i.e. the mussel (Corbicula africana) (10 100 ng sDDT . g-1 fat) and benthos feeding fish, e.g. Labeo altivelis (5700 ng sDDT . g-1 fat).