Concentrations of Heavy Metals in water and sediments from streams in the Awetu watershed and fish tissue from the Gilgel Gibe I reservoir, in Jimma zone Southwestern Ethiopia: Ecological and Human Health risk

Abstract

Extended use of substances that contain toxic contaminants like heavy metals, in industries, agriculture, and other human activities leads to the increased release of harmful heavy metals into the environment. Heavy metals are metallic elements that have a relatively high density (> 5 g/cm 3 ) and can induce toxicity at a low level of exposure. A lot of such substances released into the environment end up in the aquatic systems due to the direct discharges into water bodies and/or through run-off. Consequently, ecological risks due to the accumulation of heavy metals in the ecosystem and human health risks as a result of the consumption of water and foodstuffs contaminated with heavy metals have become serious concerns worldwide. Countries like Ethiopia, with poor pollution regulatory implementation, are among those highly affected. Jimma town, one of the oldest towns in the Southwestern part of Ethiopia, is located within the Awetu watershed that is drained by different streams. These streams and the Gilgel Gibe reservoir receive effluents that contain untreated solid and liquid wastes containing heavy metals that are generated from different industries