Study on the Bioaccumulation of Heavy Metals in Fish Samples and Physico-Chemical Analysis of Water from Lake Hawassa, Ethiopia

Abstract

Samples were collected from Lake Hawassa, from six selected sampling sites. The measured physico-chemical parameters in lake water ranged pH(7.70-8.69), TDS(437-495 mg/L), EC(0.729-0.825 mS/cm), DO(6.2-14.6 mg/L), Temp.(20.7-23.4 ⁰C), Turb.(6.3-26.7 NTU), SO₄^2-(25-16), Cl^-(42-23), F^-(17.4-5.36), NO₃-N (2.38-11.79), PO₄^3-(0.81-1.55), COD(219-1216), and BOD₅(104-590) mg/L. The concentration of detected metals in water samples were in the range Cu(0.226-0.117), Mn(0.166-0.068), Zn(0.253-0.145), Mg(35.91–14.27), Ca(57.11-35.23), Na(87.49-87.49) and K(73.02-34.26) in mg/L. According to stream and potable waters standard recommendation, the maximum value of BOD₅, COD, PO₄^3- and F^- were above the acceptable range. The detectable metal concentration in water samples analyzed were Na>Ca>K>Mg>Zn>Cu>Mn. The concentration of Mn in the present study was above USEPA but below WHO guideline. The dendrogram figure shows that metal parameter of water samples at S1 the pollution level is higher than the other sites. All the transfer factors of water were greater than 1 in fish muscle.

Keywords: Hierarchical cluster analysis, metal, physico-chemical, transfer factor.