Contamination level, source identification and health risk assessment of potentially toxic elements in drinking water sources of mining and non-mining areas of Khyber Pakhtunkhwa, Pakistan.

Accelerated mining activities have increased water contamination with potentially toxic elements (PTEs) and their associated human health risk in developing countries. The current study investigated the distribution of PTEs, their potential sources and health risk assessment in both ground and surface water sources in mining and non-mining areas of Khyber Pakhtunkhwa, Pakistan. Water samples (n = 150) were taken from selected sites and were analyzed for six PTEs (Ni, Cr, Zn, Cu, Pb and Mn). Among PTEs, Cr showed a high mean concentration (497) µg L-1, followed by Zn (414) µg L-1 in the mining area, while Zn showed the lowest mean value (4.44) µg L-1 in non-mining areas. Elevated concentrations of Ni, Cr and a moderate level of Pb in ground and surface water of Mohmand District exceeded the permissible limits set by WHO. Multivariate statistical analyses showed that the pollution sources of PTEs were mainly from mafic-ultramafic rocks, acid mine drainage, open dumping of mine wastes and mine tailings. The hazard quotient (HQ) was the highest for children relative to that for adults, but not higher than the USEPA limits. The hazard index (HI) for ingestions of all selected PTEs was lower than the threshold value (HIing < 1), except for Mohmand District, which showed a value of HI >1 in mining areas through ingestion. Moreover, the carcinogenic risk (CR) values exceeded the threshold limits for Ni and Cr set by the USEPA (1.0E-04-1.0E-06). In order to protect the drinking water sources of the study areas from further contamination, management techniques and policy for mining operations need to be implemented.

Potential harmful elements in coal dust and human health risk assessment near the mining areas in Cherat, Pakistan.

This study was aimed to investigate the potential harmful element (PHE) concentrations in coal dust and evaluate the human risk assessment and health effects near coal mining areas. For this purpose, dust samples were collected near various coal mines in Cherat, Pakistan, and analyzed for the PHE concentrations. Determined PHE concentrations were evaluated for the health risk assessment. Results revealed that ingestion was the major pathway as compared to others for PHE exposure. Individual chronic daily intake (CDI) of PHEs was higher than their respective permissible exposure limits set for oral exposure routes by the Agency for Toxic Substances and Disease Registry (ATSDR). Chronic risk or health index (HI) values were observed < 1 for all PHEs and in the order of Pb > Cr > Cd > Ni > Cu > Co > Zn. Higher HI values of Pb, Cr, and Cd could attribute to various chronic health problems as observed during the medical examination survey of this study. Cancer risk (CR) values for this study were observed within the US Environmental Protection Agency (EPA) limits. However, if current practices continued, the PHEs will cross these limits in a near future. Therefore, this study strongly recommends the provision of safety measures, rules, and regulation to avoid health hazards in the future.