Arsenic and lead come in the first and second positions, respectively, in the Comprehensive Environmental Response, Compensation, and Liability Act (CERLA) list of 275 most harzadeous substances of 2011. These metals are capable of bioaccumulation. Therefore, ingestion through food and water should be guarded against. Inhabitants of Agulu, Nigeria, depend mostly on groundwater (wells and boreholes) for their water sources, which exposes them to possible ingestion of these metals through groundwater.
The determination of the heavy metals (HM) arsenic and lead in the groundwaters of Agulu, Nigeria, and their bioaccumulation in the inhabitants was carried out using atomic absorption spectrophotometry. The contamination by these HMs of the sampled groundwater varied among Agulu villages. Arsenic was found to be in more than 41% of the samples, while 40% of them contained arsenic above the 0.01 mg/L MCL recommended by WHO. Lead was detected in 32% of the samples, with 29% being above the WHO MCL of 0.01 mg/L. While the mean blood levels of lead were within allowable limits, the mean blood arsenic levels were several times higher than the allowable limit and far above the water concentrations, which indicated bioaccumulation and chronic arsenic poisoning.
This study has shown significant heavy metal contamination in groundwaters of Agulu and concentrations of arsenic above the allowable threshold. This indicates bioaccumulation of arsenic as the average blood concentration is more than that in the groundwater studied.