Environment-Human Bioaccumulation of Lead Resulting from Artisanal Lead-Zinc Mining Activities in Ebonyi State, Southeastern Nigeria

ABSTRACT The proliferation of shallow mine pits and indiscriminate dumping of mine tailings in the environment due to artisanal Lead-Zinc mining activities within the study area puts the immediate environment at risk of lead toxicity. Considering the adverse effect of Lead toxicity on humans, it has become imperative to evaluate the availability of Lead within the environment and to ascertain the potential pathway through which the contaminant can enter the human body. For this reason, soil, plant, groundwater, surface water, and human blood samples were collected within and beyond the mine catchment area in order to determine the amount of Lead in the environment. Samples were chemically digested and thereafter subjected to spectroscopic analysis using the atomic absorption spectroscopy method for the plant, soil, and water samples, whereas inductive coupled plasma mass spectroscopy was employed for blood sample analysis. Analysis of the laboratory results revealed that the average lead concentration in the environment was 0.49 mg/kg, 0.03 mg/L, 0.04 mg/L, and 0.01 mg/L in soil, plant, surface water, and groundwater, respectively. The correlation coefficient of 0.9 between the lead concentration in plant and soil and an average bioconcentration factor of 0.20 was evidence of soil-to-plant transfer of lead. Total environment-human bioaccumulation of Lead was 3.95 of which 48%, 37%, and 15% of it were contributed by ingestion of surface water, plants, and groundwater, respectively. The average concentration of Pb2+ in the blood of the residents within the study area (0.36 mg/L) was above the normal permissible limit in human blood.