Assessment of heavy metal levels in cow's milk and associated health risks in the vicinity of the MIDROC Laga Dambi gold mine in Ethiopia

Abstract

Introduction

The possible health effects of consuming milk contaminated with heavy metals have been the subject of considerable concern worldwide.

Objective

The aim of this study was to determine the level of heavy metals in cow's milk in the vicinity of MIDROC Laga Dambi gold mine and to assess their possible health risks for consumers.

Methods

Nine composite samples were formed by aggregating 243 milk samples obtained in triplicates from 81 domestic milk-producing households. Inductively coupled plasma-optical emission spectroscopy was used to measure the amount of heavy metals after samples digestion under optimal conditions.

Results

The heavy metals concentrations obtained were 13.913˗7.843, 9.505˗3.589, 5.972˗3.147, 2.288˗1.851, 0.403˗0.143, 0.436˗0.128, 0.26˗0.153, 0.143˗0.048, 0.160˗ND (not detected), and 0.140˗ND mgkg⁻¹for Fe, Zn, Pb, Mn, Hg, Cr, Cd, As, Ni, and Co, respectively. Of the heavy metals identified, the levels of Pb, As, Cd, and Hg exceeded the recommended value. Based on the estimated daily intake (EDI), the total health quotient (THQ) is higher than unity even for Pb alone. It has been found that the consumption of cow milk increases the health index (HI) by 2.972. Ninety five percent of the HI in the study area was explained by the toxic heavy metals (Pb, Cd, As, and Hg) in the cow milk, which were found to be beyond the safe limit.

Conclusion

This demonstrates that there is a health risk to the population who consume cow’s milk sourced from the vicinity of MIDROC Laga Dambi gold mine. To safeguard the public’s health, we advised strict monitoring and legislative control for the safety of cow’s milk originating from study area.