Heavy metal contamination and health risk assessment associated with abandoned barite mines in Cross River State, southeastern Nigeria

Abstract In the present investigation, the concentration of heavy metals (As, Ba, Fe, Hg, Mn, Ni, Pb, Zn) in pond and stream water samples near abandoned barite mines have been studied. The main objective of study was to appraise the degree of contamination and human risk assessment due to barite mining. Results showed that the average concentrations of Fe, Hg and Pb were above the required standard. This indicates anthropogenic inputs from barite mining activities. The mean concentrations of Ba, Hg, Mn, Ni, Pb and Zn were higher in pond water compared to stream water. Contamination index and Nemerow pollution index indicated contamination at some mine sites, while human health risk assessment indicated unacceptable risk (hazard index (HI) values > 1) for non-carcinogenic adverse health effect. The cancer risk of being exposed to Arsenic by drinking water from these sources did not exceed the acceptable risk of 1:10,000 for regulatory purposes.