Pesticide residue in streams receiving wet coffee processing effluent oromia national regional state, jimma zone, Ethiopia

Abstract

Organochlorine pesticides (OCPs) are synthetic pesticides widely used all over the world. When present in the environment they adversely affect terrestrial and aquatic biodiversity. Thus, there has been a continual demand to monitor the presence of OCPs within the environment. The main objective of this study is to assess pesticide residues in coffee processing effluent receiving stream and biota at Bore, Haro and Agaro, Jimma zone. Farther, 18 each of water, and 12 macro invertebrates samples were collected from the three sites coffee effluent receiving streams. Extraction methods such as Dispersive Liquid-Liquid Micro (DLLME) and Soxhlet Extraction were used for the analysis of pesticides from water and macro invertebrates‟ sample, respectively. The samples were cleaned up with deactivated silica gel and the final extracts were analyzed using Gas Chromatography with Electron Capture Detector (GC-ECD). The coefficient of determination 9 pesticides showed linear correlation (r2 > 0.99). The performances of the analytical procedures were evaluated using percentage recovery and computed by spiking the blank samples with known concentration of the target analytes. The finding shows, the percent recovery for each analytes were between 81.7% and 109.1% comply with routine analysis detection requirements. Analyzed pesticides such as, Aldrin, g-chlordane, Dibuthylchlor, Endrin, Endosulfan sulfate, Dieldrin, p, p'- DDT, Methoxychlor and chloradate were detected in the water and macro invertebrates (MI) samples with varying concentration 89%, 58% and 37% of g-chlordane, Dibuthylchlor and Aldrin, were detected with the highest mean concentration in MI and water sample at the study area. The lowest detected pesticide was chloradate 0.002% in MI samples. In conclusion, water and aquatic organisms are polluted by organochlorine pesticides and may expose human, aquatic animals or general environment. Therefore, strict regulation is needed in this particular study area as well as in Ethiopia in general.