The objectives of this study were to evaluate the health risk concern of some trace metals in selected borehole drinking water proximal to open dumpsites in Benin City. Borehole water samples were collected and analysed for trace metals using standard methods. Health risk and pollution indices were used to characterise the trace metals. The average daily dosage (ADD) results showed low concentrations of the trace metals in the various borehole sites. Oluku 1 had Mn (0.04), Zn (0.11) and Cu (0.01). Oluku 2 had Mn (0.43), Zn (0.18) and Cu (0.01) while Ikueniro 1 had Mn (0.05), Zn (0.17) and Cu (0.01) and Ikueniro 2 had Mn (0.04), Zn (0.15) and Cu (0.01). The hazard quotient (HQs) and hazard index (HI) values were < 1. The results of the Metal Pollution Index (MPI) revealed the values of Oluku 1 (4.6E-06), Oluku 2 (1.0E-04), Ikueniro 1 (1.4-05) and Ikueniro 2 (5.6E-06). The classification of the water were within class 0 and 1. The findings of this study have revealed that the trace metal contents found in the boreholes waters were within the safe limits as referenced. On this premise, the borehole waters were recommended safe for consumption without any health risk impact, consequent of no evidence of pollution.

The potential ecological risk assessment of heavy metals contamination in surface sediments of Ikpoba River, Edo State was estimated in this study after assessment of heavy metal concentrations in surface sediments from seven stations of the study area. Heavy metals were analyzed in the sediments using Atomic Absorption Spectrophotometer. The index of geo-accumulation for the metals (Lead (Pb); Iron (Fe); Nickel (Ni) and Copper (Cu)) studied were less than zero showing that the stations sampled were unpolluted with heavy metals. Contamination factor followed same pattern. Generally, there was a low potential ecological risk for heavy metal contamination to sediment dwelling organisms. However, station 4 (Capitol) was moderately contaminated and extremely enriched with Cu. Heavy metal values in this study were below the EPA limits for sediments except station 4 which was heavily polluted with Cu following the EPA guidelines. Regular monitoring and assessment of pollution load of Ikpoba River is recommended.

Heavy metals contents (Zn, Cd, Fe and Pb) were analyzed in canned foods frequently consumed in Benin City. Samples were collected from major supermarkets. These samples were categorized into 3 distinctive groups of 3 varying brands with triplicates each of fish, beans and vegetables (Peas, Carrots and Green Beans). The metals were analyzed using atomic absorption spectrophotometer (AAS). The results showed significant differences (p < 0.05) in the values of Cu and Fe and a highly significant difference (p < 0.001) in Cd in the different brands of canned fish samples. Iron Fe, was found to be prevalent in all classes of food tested with values as high as 20.57±1.14 mg/l in Peas (Del Monte). Concentrations of Fe in body tissues must be highly monitored because in excessive amounts, it can lead to tissue damage. Similarly, for all brands of canned foods examined, Cd had the lowest mean concentration (0.01 ± 0.00) mg/kg in all brands of canned fish. A regular monitoring of canned foods available to the public is recommended to safeguard public health especially when recommended levels are exceeded.