Electrochemical determination of the levels of lead and cadmium in soil samples from Niger and Ogun States, Nigeria: remediation potential with chitosan phosphate and implications for human health and disease

Abstract

Lead and cadmium poisoning is common in some parts of Nigeria as a result of artisanal mining of gold. The poisoning has led to the deaths of hundreds of women and children below the age of five years. In this study, the concentrations of lead and cadmium in eight soil samples collected from selected artisanal gold mining locations in Niger State and battery dismantling site in Ogun State were electrochemically determined. Linear sweep stripping voltammetry technique was used with glassy carbon as working electrode, Ag/AgCl as reference and platinum as auxiliary electrode. The cathodic peak current for the reduction of lead was observed at − 490 mV while that of cadmium was observed at − 675 mV. The concentrations of lead in the soil samples ranged between 19 and 417 mg/kg while that of cadmium was in the range 20–182 mg/kg. The ability of chitosan phosphate to adsorb lead and cadmium in the polluted soil samples was investigated as a step towards carrying out remediation of the polluted environment. Chitosan phosphate was derived from chitosan which was prepared by the deacetylation of chitin obtained from crab. The chitosan phosphate was found to remove the lead and cadmium from all the soil samples studied.