Concentration of Heavy Metals in Vegetables Cultivated around Dumpsites in Jimeta and Ngurore Areas, Adamawa State, Nigeria

Abstract

The study analyses the health risk assessment of the concentration of Iron, Lead, Copper, Chromium, and Cadmium heavy metals in vegetables grown near dumpsites of Jimeta and Ngurore areas of Adamawa State, Nigeria. Vegetables mainly Spinach (Spinacia oleracea) and lettuce (Lactuca sativa) were collected in triplicates and analyzed using Atomic Absorption Spectrophotometer Buck 210VGP (AAS). The result revealed that heavy metals detected in spinach at Jimeta dumpsite decreased in the following order: Fe (3.7 mg/kg) > Pb (0.18 mg/kg) > Cu (0.12 mg/kg) > Cr (0.07 mg/kg) > Cd (below limit of detection), compared to the metal concentration in spinach at Ngorure dumpsite with lower concentration of heavy metal which decreased in the order of: Fe (2.5 mg/kg) > Pb (0.16 mg/kg) > Cu (0.14 mg/kg) > Cr (0.02 mg/kg) > Cd (below limit of detection). Other result for Spinach in Jimeta decreased in the order Fe (3.31mg/kg) > Pb (0.2mg/kg) > Cu (0.11mg/kg) > Cr (0.05mg/kg) > Cd (ND) beyond the limit of detection while Lettuce decreased in the order Fe (22.54mg/kg) > Cu (0.31mg/kg) > Pb (0.12mg/kg) > Cr (0.07mg/kg) > Cd (ND) beyond the limit of detection. Fe is the most abundant element in the vegetables with a mean value of 21 mg/kg followed by Pb (0.177 mg/kg). The analyses of paired T-test for vegetables in Ngurore and Jimeta at 0.05 level of significant confirmed that Cu and Cr showed no statistically significant difference in their concentration level while Fe and Pb confirmed that there was statistically significant difference in their concentration level. However, the detection of heavy metals in these vegetables calls for close environmental monitoring and adequate public awareness. This is necessary to discourage further pollution which could lead to high metal concentration and metal poisoning in vegetables and invariably humans that consume them.

Keywords: Spinacia oleracea, Lactuca sativa, Heavy metal, Atomic Absorption Spectrophotometer