Heavy Metal Concentration And Health Risk Assessment In Soil, Vegetables, And Water Of Central Rift Valley, Ethiopia

Abstract

Mulate Zerihun, Masresha Minuye, Aserse Yensew, Kebede Dida and Solomon Abate

Background
Several heavy metals are toxic to organisms including human and therefore their entry into food chain from polluted agricultural
land is required to be controlled. The objective of this study was to investigate the impact of industrialization on the quality of
agricultural products and environments in the area of the central rift valley, Ethiopia. The samples of soils, water, and vegetables
were randomly collected, processed, and analyzed for heavy metals using microwave plasma atomic emission spectroscopy (MPAES). Also, it examines potential health risks from the consumption of these vegetables.
Results
The result shown the average concentration gradient of metals in the soil, water, and vegetables (ppm) was Ni<Co<Cd<Pb<Cu<Cr<Zn<Mn<Fe. According to the statistics, Pearson cross-correlation analysis results for the element pairs of CoNi (0.879), Cr-Cu (0.582), Fe-Cr (0.597), Fe-Cu (0.581), Fe-Pb (0.587) and Fe-Cu (0.694) were showed the highest and positive.
Metals with the highest positive correlations indicated that the same behavior in the environment, increasing or decreasing
together in the environment. The correlations obtained between Cr-Mn, Cr-Zn, Cu-Mn, Cu-Zn, Mn-PB, and Ni-Zn was the
moderately highest among the others. The moderately high correlations between these metals indicated that the pollutants
possibly shared the same source, whereas the others may have arisen from individual sources in the region. Moreover, the soil
concentrations of Fe, Mn, Zn, and Cr were also high and higher compared with the level of different countries' standards. The
average daily intake for Pb(7.79), Fe(2755.38), Zn(55.83) and Cu(639.05) mg/person/day were above the permissible maximum
tolerable daily intake of 0.21, 15, 15, 2.0mg/person/day endorsed by WHO/FAO. Hazard quotient of Pb, Fe, Zn, Zn, Mn and Cu
as well as the hazard indices of selected vegetables were exceeded unity, signifying presence of health risks from consumption of
the vegetables.
Conclusion
Based on the results of this study, heavy metals had a significant health risk (both non-carcinogenic and carcinogenic) effects to
the consumer associated with the consumption of these vegetables grown within the study area. Consequently, we recommend a
strict regulatory control on the safety of vegetables originated from the study area and food chain.

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