Abstract

<p>This study investigates the accumulation of heavy metals in pawpaw (Carica papaya) cultivated around dumpsites in Nekede Mechanic Village, Owerri, Imo State, Nigeria. The research evaluated the microbial, physicochemical, and heavy metal properties of soils and pawpaw plants from two dumpsite locations, with a control site in Ihiagwa. Total bacterial counts in soil ranged from 2.8x10^7 to 7.0x10^8 cfu/g, while total heterotrophic fungi counts ranged from 1.3x10^4 to 7.0x10^4 cfu/g. Additionally, the total coliform and faecal coliform counts were 1.1x10^5 to 6.0x10^5 cfu/g and 8.0x10^4 to 3.0x10^5 cfu/g, respectively. Various bacterial and fungal species were identified, including Enterobacter, Escherichia, Aspergillus fumigatus, and Fusarium. Heavy metal concentrations in soil were highest at the dumpsites, with values for Fe, Al, As, Cu, Hg, Zn, Pb, Ni, and Cd in the range of 0.00 to 65.17 mg/kg. In comparison, control site concentrations were significantly lower. The mean heavy metal concentrations in pawpaw samples did not significantly differ across sampling locations, except for copper (Cu), which showed significant variation. The levels of cadmium (Cd), zinc (Zn), aluminum (Al), lead (Pb), nickel (Ni), arsenic (As), and mercury (Hg) in pawpaw exceeded the FAO/WHO permissible limits for food crops. Although heavy metal levels were found in pawpaw, the dilution effect due to the plant’s water content may have minimized the absorption. Given the potential health risks posed by the high concentrations of these metals, it is advised that pawpaw grown near dumpsites not be consumed. The study recommends improved waste management practices in mechanic villages and suggests cultivating crops at least 50–100 meters away from dumpsites to reduce contamination</p>