Occurrence of heavy metal in water, soil, and plants in fields irrigated with industrial wastewater in Sabata town, Ethiopia

Industrial wastes have been increasingly discharged into water and soil, and causing environmental pollution in Ethiopia. This study examined the occurrence of heavy metal in water, soil, and plants in fields irrigated with industrial wastewater in Sabata town, Ethiopia. The composite samples of soil, water, and vegetables were collected accordingly to determine the concentration of heavy metals (Cu, Pb, Zn, Mn, and Ni) in each system during dry and wet seasons. The concentration of heavy metal was assayed using atomic absorption spectrophotometry. The data were statistically analyzed using one-way ANOVA. The heavy metal concentration was decreased in the order of Pb > Mn > Ni > Cu > Zn, Mn > Ni > Pb > Cu > Zn, and Ni > Pb > Mn > Cu > Zn in the water, soil, and vegetables in the area respectively. The variation of levels of heavy metal in the water, soil, and vegetable might be because of the effect of heavy metal speciation and valence, industry types, vegetable types and tissues, and soil. The bioconcentration factor of heavy metals was higher than that one for copper, signifying the increased probability of health risk for those who are consuming vegetables grown in the area. Thus, the government should take this into account and devise mitigation strategies through the implementation of heavy metal removal systems from contaminated water and soil, waste management strategies of recycling, centralized or decentralized treatment plant, changing of industrial residual into biogas production, and awareness creation for the society.