Detections of Organochlorine Pesticides in Water, Sediment, and Fish Samples in Lake Tana and Lake Hayqe, Ethiopia

Abstract The extensive use of pesticides considered as a global threat to the ecological integrity of aquatic ecosystems. Most developing countries including Ethiopia are burdened with these toxic and persistent pesticides due to their wider used for agricultural pest and malaria control. The present study was aimed to investigate the concentration of Organochlorine pesticides water, sediment and fish samples in Lakes Tana and Hayqe. Eight samples of each water and sediment and five fish samples were collected. A laboratory based cross sectional study was conducted from Dec 2020 to March 2021 in Lakes Tana and Hayqe. A more sensitive method for the determination of 18 Organochlorine pesticides in water, sediments, and fish samples were adopted using QuEChERS and the analyses were done using GC-MS. Water samples were processed using a liquid–liquid extraction technique and gas chromatograph equipped with mass spectroscopy (GC-MS). Dispersive-solid-phase extraction (d-SPE) was used for fish and sediment samples followed by cleanup and gas chromatograph Mass Spectroscopy. In the method validation, Percent of recovery ranged from 88.4-107.6%. From the result lindane (1.11 µg/L) was recorded the lowest concentration of OCPs in water samples and total endosulfan was the highest (14.97µg/L). In sediment samples, deltamethrin (11.21 µg/kg) was the lowest and endrin (70.42 µg/kg) was the highest OCPs. From fish samples, lindane (12.63 µg/kg) was the lowest and total endosulfan (68.78 µg/kg) was the highest concentration. The ANOVA test and t-test also depicted that the levels of most pesticides were significantly varied with different sampling sites and between Lakes.