摘要
Concentrations of OCP(Organochlorine Pesticide)residues were determined in cultured Nile tilapia(Oreochromis niloticus)fish in target stations within 1st order wetland of River Kuja,Kenya,between February-November,2017.The aim was to assess the residue levels in wild and pond cultured fish within a heavily populated agricultural area of South Western Kenya.Biota samples were analysed for selected HCHs(Hexachlorocyclohexane)isomers,DDT(Dichlorodiphenyltrichloroethane)and metabolites and cyclodienes pesticide residues using GC-ECD(Gas Chromatography Equipped with Electron Capture Detector).Most of OCPs observed were BDL(Below Detection Limit)to detectable levels.Larger percentages(>50%)of DDTs and HCHs were BDL and exhibited consistency,with significant(p<0.05)differences in mean contamination levels in fish within the wetland,with average muscle tissue pesticides concentrate ranging between 0.229-2.541mg/kg for Nile tilapia.Most dominant isomer in target species was Lindane(g-HCH)(3.417±0.983mg/kg)and Endosulfans.Mean Endosulfan sulfate was 2.499±0.071mg/kg d.w.and most frequently detected,and Methoxychlor(2.235±1.459mg/kg),respectively.Mean Aldrin and Dieldrin was 2.028 and 0.574mg/kg d.w.Concentration for DDT and its metabolites was 0.27-3.71mg/kg for p,p’-DDE(DichlorodiphenylDichloroEthene),BDL-1.098 for p,p’-DDD(DichloroDiphenylDichloroEthane),and 0.105-3.518mg/kg for p,p’-DDT with significant differences in mean values and ranges whose levels were below the WHO(World Health Organization)maximum acceptable thresholds of 0.2,2,20 and 5.0mg/kg in fish and sea food.Interventions and monitoring need up-scaling in minimizing public health risks posed by consumption and exposure.
基金
The authors would like to acknowledge NACOSTI(National Council Science Technology&Innovation),for providing research funds
the Director of KMFRI(Kenya Marine and Fisheries Research Institute)for logistical support,and colleagues from KMFRI technical staff(J.Ouko,R.Mairura,and Z.Awuondo).We also wish to thank the technical staff of UoN(University of Nairobi),Chiromo Laboratories,for instrumental data handling and analysis.
