Human Health Risk Assessment for Consumption of Vegetable Cultivated by Fertigation of Municipal Solid Waste Compost with Natural Soil in Jimma Town, Ethiopia

Abstract

Background: Heavy metal pollution is a menace to our environment as they are foremost contaminating agents of our food supply, especially vegetables. This is great concern to the public health, agricultural production, and environmental health. Objective: to assess human health risk for consumption of vegetable cultivated by fertigation of municipal solid waste compost with natural soil in Jimma town, Ethiopia. Methods: The study was conducted in Jimma town 2019 by using cross sectional study design. The samples were collected during dry season for heavy metal analysis from two sites (Abdi Jimma and Aba Milki sites). Heavy metal concentration was analyzed by atomic absorption spectrophotometer. Health risks associated with these heavy metals (As, Cd, Cr, Pb, Cu and Zn) from consumption of vegetable (tomato, beetroot, lettuce, onion and spinach) were assessed based on total hazard quotients: Findings: The concentration of heavy metals in edible parts of vegetables increase in vegetables grown in Abdi Jimma when compared with Aba Milki farm site metal concentration for Zn, Pb, Cu, and As. The mean metal concentrations in vegetable for As(0.72) and Zn(65.48) was above the safe limits of World Health Organization’s standards, while the mean Cd(0.0745), Cr(0.36), Pb(0.176) and Cu(3.33) concentration were below safe limit. Health risk for As, Cd, Cr, Pb, Cu and Zn, possess nearly free of risk to the local in habitants through consumption of contaminated vegetable grown in the area as the value for total hazard quotient was less than 1, but the long term accumulation of these metal gradually increase the concentration in the environment and accumulates in the body and can cause serious health problems. Conclusions: Natural compost preparation from waste materials requires detail characterization and selecting waste items with low concentration of heavy metals. Regular monitoring of heavy metals is essential to prevent excessive build up in the food chain and prevent serious health risk of population. Recommendation: the composition of organic fertilizer and the soils from which vegetable crops can grow should be monitored and regulated.