Assessment of Heavy Metal Accumulation from Abattoir Wastes on Soil and Selected Edible Vegetables at Ikwiriri Slaughterhouse, Rufiji District.

Ibrahim, Ahmada Moh’d (2025) Assessment of Heavy Metal Accumulation from Abattoir Wastes on Soil and Selected Edible Vegetables at Ikwiriri Slaughterhouse, Rufiji District. Masters thesis, The Open University of Tanzania.

PDF - Submitted Version Available under License Creative Commons Attribution. Download (1MB)

Abstract

This study assessed heavy metal contamination and associated health risks in green leafy vegetables cultivated using slaughterhouse wastewater in Ikwiriri Ward, Tanzania. A total of three vegetable species (Vigna sp., Ipomoea sp., and Cucurbita sp.), 12 soil samples, and 6 wastewater samples were collected and analyzed for Pb, Cr, Cu, Zn, and Fe using microwave plasma atomic emission spectroscopy (MPAES) following microwave-assisted digestion. Heavy metal concentrations in vegetables ranged from 0.073 ± 0.011 to 0.158 ± 0.071 mg/kg (Pb), 0.182 ± 0.096 to 0.437 ± 0.181 mg/kg (Cr), 1.212 ± 0.208 to 2.307 ± 0.335 mg/kg (Cu), 2.933 ± 0.305 to 7.740 ± 0.928 mg/kg (Zn), and 15.543 ± 1.649 to 58.991 ± 17.196 mg/kg (Fe). In wastewater, Fe (2.098 ± 0.479 mg/L) showed the highest levels, followed by Zn (0.121 ± 0.030 mg/L), Pb (0.099 ± 0.076 mg/L), Cr (0.030 ± 0.001 mg/L), and Cu (0.027 ± 0.012 mg/L). While Cr, Zn, and Cu were within WHO and TBS permissible limits, Fe and Pb concentrations exceeded drinking-water thresholds, with Pb approaching the effluent limit (0.1 mg/L). Human health risk assessment revealed hazard indices (HI) in the order: Vigna sp. (1.65) > Cucurbita sp. (1.53) > Ipomoea sp. (0.75). Although individual metals posed limited risks (HQ < 1), cumulative noncarcinogenic risks (HI > 1) for Vigna sp. and Cucurbita sp. suggest potential health concerns, particularly for frequent consumers. These findings highlight the need for effective wastewater management, monitoring of leafy vegetables near abattoirs, and public health interventions to minimize exposure risks. Keywords: Abattoir Waste, Heavy Metal, Hazard Index, Health Risk Assessment.

Actions (login required)

View Item