The study investigate a series of selected heavy metal pollution of soil, the extent of their uptake by Telfairia occidentalis and Amaranthus cruentus as well as their ecological risk around dumpsite in Chanchaga Minna, Niger State, Nigeria. Soil samples were collected at 15 cm depth with the aid of soil auger and vegetable samples were collected from dumpsite and other samples with no activities served as control. The soil samples were collected at random and their physicochemical parameters such as pH, total nitrogen, total phosphorus, organic matter, total carbon and exchangeable cations (i.e., K+, Mg2+ and Na+) using a standard method and concentrations of the heavy metals in soils and vegetables, As, Cd, Cr, Cu, Hg and Pb were analyzed using flame Atomic Absorption Spectrometer (AAS). The ecological health risk assessment from the consumption of these vegetables was calculated using standard methods. The result showed a significant (p-value) increase of AC and TO in test soil samples relative to the control soils. The pH of the soil in dumpsite and control site was 5.93, and 7.35 respectively. Mean concentrations of As, Cd, Cr, Cu, Hg and Pb in the dump site were 6.35, 4.84, 6.67, 7.35, 5.72 and 4.96 mg/kg while the control site were 1.18, 0.28, 1.26, 6.83, 1.19 and 3.54 mg/kg respectively which was below the WHO/FAO limits of As (20), Cd (3.0), Cr (100), Cu (100), Hg (2.00) and Pb (50 mg/kg) for soil. The concentrations of As, Cd, Cr, Cu, Hg and Pb recorded in AC dump site were As (6.13), Cd (3.67), Cr (5.37), Cu (4.28), Hg (3.46), and Pb (4.52) and in TO As (5.67), Cd (3.13), Cr (4.67), Cu (3.65), Hg (3.19) and Pb (4.27 mg/kg) which were above the WHO/FAO permissible limits (0.5, 0.20, 0.3, 3.0, 0.1 and 0.3 mg/kg) respectively for edible vegetable. The concentrations of heavy metals in soils and vegetables from the dumpsite soil were significant (p < 0.05) from the controls. The bioaccumulation factor (BAF) for the vegetable showed that they exclude the element from soil. The Hazard Quotient (HQ) and Hazard index (HI) show that there is no harmful effect since the values obtain were not greater than >1. But continuous consumption can accumulate in the food chain especially for children. This study showed that the soils and vegetables within the vicinity of the dumpsites were polluted by heavy metals which can pose health risk. The study also calls for proper waste management practices and policy implementation.

This study investigated the concentrations of heavy metals (As, Cd, Cr, Cu, Hg and Pb) in African Giant Land Snail (AGLS) treated with different soil samples dumpsite (A), mining site (B) and control soil (C) (a reserve area where no activities) use in farming AGLS and also to ascertain if they are within permissible limits and its ecological risk assessment on the consumption. Soil samples; at site A, B and C was collected at 0-30 cm depth with the aid of soil auger and were used for AGLS farming, to ascertain whether the potentially toxic elements (PTEs) concentration were within the permissible limits and their ecological risk assessment on AGLS consumption. A total of 54 juvenile snails of similar weights was used for the study. The experiment lasted for six month (182 days), during which the snails were subjected to similar dietary reign and equal quantity of feed. Snail’s morphological characteristics such as Weight, length and diameter of its shell were measured after farming. The soil samples were analysed for PTEs before and after farming, and snail were also analyzed for PTEs after farming for six month using atomic absorptions spectrophotometer (AAS). The ecological health risk from the consumption of these snails was assessed using standard methods and formulas. The result of different soil before and after farming shows a significant different (P<0.05) between the activities sites (dump and mining) and the control site. The concentration of PTEs (As, Cd, Cr, Cu, Hg, and Pb) in snails treated with dump site soil were 3.05, 3.89, 3.60, 2.89, 3.98, and 2.55 mg/kg, and snails treated with mining site soil recorded 2.73, 2.74, 3.91, 4.96, 2.88 and 4.82 mg/kg. The values were greater than the maximum permissible limit of 0.5, 2.0, 0.3, 0.04, 0.1 and 0.1 mg/kg respectively recommended by FAO/WHO compared to the control. The study concludes that snail bioaccumulate toxic elements from the soil used in rearing them which is deleterious to humans when consumed. Also the DIM, HQ, HI on the consumption of snail reared with dumpsite, mining site soils are nearly free of risks, but continuous consumption can lead to bioaccumulation in the food chain.