Potentially toxic elements in soil of the Khyber Pakhtunkhwa province and Tribal areas, Pakistan: evaluation for human and ecological risk assessment.

Potentially toxic elements (PTEs) contaminations in the soil ecosystem are considered as extremely hazardous due to toxicity, persistence and bioaccumulative nature. Therefore, this study was aimed to summarize the results of published PTEs in soil of Khyber Pakhtunkhwa and Tribal areas, Pakistan. Results were evaluated for the pollution quantification factors, including contamination factor (CF), pollution load index (PLI), ecological risk index (ERI) and human health risk assessment. The highest CF (797) and PLI (7.35) values were observed for Fe and ERI (857) values for Cd. Soil PTEs concentrations were used to calculate the human exposure for the risk assessment, including chronic or non-carcinogenic risks such as the hazard quotient (HQ) and carcinogenic or cancer risk (CR). The values of HQ were > 1 for the Cd, Co and Cr in Khyber Pakhtunkhwa and Tribal areas. Tribal areas showed higher values of ERI, HQ, and CR as compared to the Khyber Pakhtunkhwa that were attributed to the mining activities, weathering and erosion of mafic and ultramafic bedrocks hosting ophiolites. This study strongly recommends that best control measures need to be taken for soil PTEs with the intent to alleviate any continuing potential threat to the human health, property and environment, which otherwise could enter ecosystem and ultimately the living beings. Further studies are recommended to combat the soil PTEs concentrations and toxicity in the Tribal areas for a best picture of understanding the element effects on human, and environment can be achieved that will lead to a sustainable ecological harmony.

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.

Wild plant assessment for heavy metal phytoremediation potential along the mafic and ultramafic terrain in northern Pakistan.

This study investigates the wild plant species for their phytoremediation potential of macro and trace metals (MTM). For this purpose, soil and wild plant species samples were collected along mafic and ultramafic terrain in the Jijal, Dubair, and Alpuri areas of Kohistan region, northern Pakistan. These samples were analyzed for the concentrations of MTM (Na, K, Ca, Mg, Fe, Mn, Pb, Zn, Cd, Cu, Cr, Ni, and Co) using atomic absorption spectrometer (AAS-PEA-700). Soil showed significant (P < .001) contamination level, while plants had greater variability in metal uptake from the contaminated sites. Plant species such as Selaginella jacquemontii, Rumex hastatus, and Plectranthus rugosus showed multifold enrichment factor (EF) of Fe, Mn, Cr, Ni, and Co as compared to background area. Results revealed that these wild plant species have the ability to uptake and accumulate higher metals concentration. Therefore, these plant species may be used for phytoremediation of metals contaminated soil. However, higher MTM concentrations in the wild plant species could cause environmental hazards in the study area, as selected metals (Fe, Mn, Cr, Ni, Co, and Pb) have toxicological concerns.