Organochlorine pesticide residues in soil from sugarcane plantations in Kilimanjaro, Tanzania

Soil samples from the Tanganyika Planting Company (TPC) sugarcane plantations in Kilimanjaro, Tanzania, an area of intensive pesticide application, were analysed for historic and current-use pesticidecontamination. Twenty eight samples were collected from 7 stations within and outside the plantations during the dry and the rainy seasons. Solid-liquid extraction and gel-permeation chromatography methods were usedbefore analysis of pesticides by GC-ECD and GC-MS. Blank and spiked recovery tests were used to validate the analytical procedure. DDT and its metabolites (p,p’-DDD and p,p’-DDE), aldrin, dieldrin, heptachlor,heptachlor epoxide, HCHs (-a, -b, -d and -g isomers), and chlordane were detected in more than 90% of the samples analysed in concentrations ranging from below detection limits (bdl) to 745.9 ng/g dw. The detectionand concentration trends were ÓDDT > ÓHCH > Óheptachlor > dieldrin > g-chlordane > aldrin. The highest concentration values were obtained during the dry season and in the application areas. The presence oforganochlorine pesticide residues at concentrations reported in this study two decades after cessation of their use emphasizes the need for continuous monitoring and risk assessments.