Occurrence and distribution of Organochlorine Pesticide Residues in Water and Sediments of Earthen Fish Ponds in South Western Kenya

Persistent organochlorine residues in the environment are a threat to ecological health of aquatic organisms and pose risk both animals human consumers. Organochlorine pesticides were determined water sediments collected during wet dry season from selected riverine earthen fish pond sites high altitude catchment areas within Kuja River (Kenya) between August 2016–May, 2017. Analysis DDT metabolites, Hexachlorocyclohexanes (HCHs) isomers cyclodienes using gas chromatograph (GC), electron capture detector (ECD), confirmed GC - Mass Spectrometry (MS). Mean (± Standard error) results DDTs, HCHs waters were:- below detection level (BDL) 0.27±0.03µg/L, BDL 0.11±0.00µg/L, 4.39±1.01µg/L respectively; 0.23±0.01µg/L, 1.20±0.005µg/L, 1.71±0.02µg/L river respectively. Sediment mean OCPs contents significantly (p<0.05) higher for Dieldrin (3.043±0.43µg/kg), Endrin (2.56±0.460µg/kg), Heptachlor (3.61±0.02µg/kg) (2.97±1.32µg/kg), Endosulfan (6.31.27±1.051µg/kg), Methoxychlor (2.15±1.641µg/kg) Lindane (2.96±1.32µg/kg), A longitudinal spatial distribution pattern was noted sediment contents, demonstrating that predominant contaminants point non-point sources courses. The study recommends continuous monitoring upstream informed management policy decisions on pesticide use.
 Keywords: Kuja-Migori River; Organic contaminants; Pesticide.