Publications by authors named "Ermias Deribe"

Organic pollutants in the Ethiopian Rift Valley Lakes are the major factors that contribute to severe environmental problem. SPMDs were deployed for the analysis of selected organic pollutants for 1 month at 2 sites in Lakes Hawassa, Ziway and Koka, Ethiopia. From SPMDs placed in the three lakes, the predominant OCPs were DDT which comprise 67% and followed by endosulfan 23% of the total organochlorine pesticides (OCPs) retrieved.

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Dietary intake of fish containing organic contaminants poses a potential threat to human health. In the present work, an assessment has been carried out to look at the human health risk associated with consumption of fish contaminated with organochlorine pesticides (OCPs) and polychlorinated biphenyles (PCBs) in certain fish species collected from Lake Hawassa, Ethiopia. The health risk assessment was made by comparing the concentrations of OCPs and PCBs in fish muscle tissues with reference doses given in the USEPA guidelines.

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Article Synopsis
  • The study investigated the presence of DDT and its metabolites in four fish species from Lake Ziway in Ethiopia, finding 4,4'-DDE as the most common compound with concentrations ranging from 1.4 to 17.8 ng g(-1) wet weight.* -
  • Although the levels of DDT in these fish were lower than those in other African lakes, the detection of DDT in all samples suggests ongoing contamination, particularly highlighted by a ratio indicating recent exposure.* -
  • Biomagnification of 4,4'-DDE was confirmed, especially in the top predator species Clarias gariepinus, which had significantly higher concentrations compared to other fish, though the overall biomagnification rate was lower
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The concentrations and bioaccumulation of persistent organic pollutants (POPs) were determined in four fish species from Lake Koka, Ethiopia, representing 2-3 levels in the food chain of the lake. Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, polychlorinated biphenyls (PCBs) and chlorpyrifos were identified, with DDTs as the most predominant pesticide, with concentration ranging from 0.05 to 72.

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The QuEChERS method developed for 22 organochlorine pesticides (OCPs) and 7-polychlorinated biphenyls (PCBs) in fish tissue involves a simple and efficient freezing technique for removal of lipids. The equipment developed consists of disposable syringes and a freezing block constructed from simple materials found in most laboratories. The freezing block keeps the temperature in the extract at -20.

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