Toxicologia Ambiental e Analítica

Residues Analysis of Organochlorine Pesticides in Fish, Sediment and Water Samples from Tekeze Dam, Tigray, Ethiopia

Abstract

Teklit GA

The study was conducted to assess the levels of organochlorine (OC) pesticide residues in Lake TeKeze dam have been investigated using water, sediment and fish (Labeobarbusspp, Clariasgariepinus and Oreochromis niloticus) samples as a case study to find out the extent of pesticide contamination and accumulation in the lake. Six OC pesticides namely DDT, DDE, Lindane, Endosulfan, Heptachlor and Chlordane were analyzed in four sites at two seasons. Water samples were processed using a liquid-liquid extraction technique and gas chromatograph equipped with electron capture detector (GC-ECD). Soxhlet extraction was used for fish and sediment samples followed by clean up and gas chromatograph. DDE was the predominant residue in all the samples analyzed, at the mean concentrations of 0.052 ppb, 9.80 ppb and 4.81 ppb in water, sediment and fish samples, respectively. The lowest levels of OC pesticides were related to Heptachlor and Chlordane which none of them were found in water samples. It also indicated the extensive presence and usage of these pesticides in the study environment, which include recent use of this pesticide for agricultural purposes. Thus, the use of these pesticides to control pest by farmers within the study area with little or no knowledge must be checked through adequate control of the trade and use of pesticides and the enforcement of appropriate sanctions.