Levels of Some Trace Metals in Fishes Tissues, Water and Sediment at Tendaho Water Reservoir, Afar Region, Ethiopia

Wondimagegne Asefa,Tarekegn Beranu

doi:10.4172/2161-0525.1000313

Abstract

The levels of trace metals (Cd, Co, Cu, Mn, Fe, Pb, Zn, Cr and Ni) in three commercially important fish tissues and their environment of a newly constructed manmade dam, Tendaho reservoir, investigated using validated analytical method under appropriate quality control measures. The analysis result of samples after wet digestion with flame atomic absorption spectroscopy showed that excluding Zn, Mn and Co (fishes tissue>sediment>water) metals distribution in fishes tissue and their environment existed in the order of: sediment>fishes tissue>water. In fish species regardless of the type, the levels of almost all metals were higher in detoxification organs (gill and liver) than in muscle. Higher values of calculated bioconcentration factor and two-way ANOVA analysis result (P-value<0.05) also indicated that the highest level of majority metals existed in Catfish in compared to Tilapia and Barbus intermedius. The concentrations of Mn, Fe, Pb and Cr were higher than Ethiopian Environmental Protection Authority (2003) guidelines in water while the levels of all metals were below PEL guidelines of USEPA (2000) for sediment. Safety of customers from trace metal pollution hazard from fishes was indicated by low level of calculated hazard quotient and comparisons result with WHO (1989) and USFDA (1993) guideline values.

Highlights

Following the recent urbanization and economic developments in Africa, environmental pollution has increased [1]
Ethiopia does not have the industry that flourished in developed countries and pollutants are not produced in large quantities, pollution due to human activities and by natural inorganic chemicals cause many changes in the aquatic environment as observed in many rift valley water bodies [4,5]
The reservoir is located in very hot area with average temperature ranging from above 28.5°C where evapo-transpiration greatly exceeds mean annual rainfall that leads to the accumulation of salts on surface soil from the ground water and closeness to Ethiopia-Djibouti rides of highway increases concentration of salt and toxic elements

Summary

Introduction

Following the recent urbanization and economic developments in Africa, environmental pollution has increased [1]. This makes African aquatic environments as final sinks for trace metal pollutants originated from agricultural and industrial activities and spillage of leaded gasoline from watercrafts [2,3]. Ethiopia does not have the industry that flourished in developed countries and pollutants are not produced in large quantities, pollution due to human activities and by natural inorganic chemicals cause many changes in the aquatic environment as observed in many rift valley water bodies [4,5]. Awash River is major water sources of Tendaho reservoir. Pollutants from suburb of Addis Ababa and other cities enter Awash River carrying the whole burden of all types of raw effluents from industrial and agricultural sources. The reservoir is located in very hot area with average temperature ranging from above 28.5°C where evapo-transpiration greatly exceeds mean annual rainfall that leads to the accumulation of salts on surface soil from the ground water and closeness to Ethiopia-Djibouti rides of highway increases concentration of salt and toxic elements

Methods

Results

Conclusion