DETERMINATION OF THE LEVEL OF SELECTED HEAVY METALS IN RAW COW MILK AND SURFACE WATER AROUND LEGA DEMBI GOLD MINING AREAS, ETHIOPIA

<strong>ABSTRACT</strong>: The presence of high levels of heavy metals in drinking water and milk has negative consequences on the health and wellbeing of human beings. In the Odo Shakiso District where this study was undertaken, various health problems have been observed in the local community, including birth defects, spontaneous abortions and nervous system damage leading to paralysis and physical abnormalities including deformed limbs, mental incapacity, tumors, headaches, skin conditions, and vision problems and other effects .The main objective of present study was to investigate the concentrations of some selected heavy metals such as Cu, Zn, Cd, As, Cr, Ni, Hg, Pb, Mn, Fe, and Co in cow milk and surface water around Lega Dembi gold mine. A total of 27 raw cow milk samples and 27 surface water samples were collected and homogenized to 9 samples for both milk and water samples. The sample were digested by using 5ml of concentrated 69 % HNO3 for water sample and 9mL of 69 % HNO3 and 2ml of 30% H2O2 was used for digestion of milk samples. All samples were digested on hot plate and the concentrations of heavy metals were measured by using ICP-OES. Mean concentration of 9.955 mg/L, 2.457 mg/L, 0.307 mg/L, 1.843 mg/L, 0.392 mg/L, 0.317 mg/L, 0.016 mg/L, 0.056 mg/L, 0.883 mg/L, 0.072 mg/L, 0.066 mg/L for surface water and 9.351mg/L, 1.998mg/L, 5.732mg/L, 0.056mg/L, 0.071mg/L, 0.105mg/L, 0.283mg/L,4.629mg/L, 0.227 mg/L, 0.264 mg/L in raw cow milk were obtained for Fe, Mn, Zn, Ni, Co, Cd, Hg, Pd, As and Cr respectively. The concentrations of the heavy metals in water and raw cow milk were compared with the maximum allowable concentration (MAC) set by WHO for drinking water and IDF for raw cow milk. Depending on obtained result, the mean concentration of Pb, Hg, Cd, As and Mn were above WHO permissible limit and 95% of hazard index was accounted by them; while Zn and Cu were BDL and the remain metals are comparable WHO standards. The elevated concentration in the entire raw cow’s milk samples are probably from the water source around the study area but not the sole source. Based on the finding of this study, it is recommended that the mining industry, government and other responsible authorities to take appropriate corrective measures to protect public health.