Estimation of health risk to humans from heavy metals in soil of coal mines in Harnai, Balochistan

Abstract

ABSTRACT Presence of heavy metals in soil and atmospheric dust of coal mines have adverse effects on human health through inhalation, dermal contact and ingestion exposure. These effects include lung cancer, heart disease, and respiratory infections in children and chronic bronchitis in adults. This study presents the concentration of heavy metals in soil of Dukki and Sharigh coal mines in Balochistan and health risks through inhalation, ingestion and dermal contact of soil. Proton induced X-ray emission (PIXE) was used for investigation of heavy metals in soil of coal mines. Carcinogenic and non-carcinogenic risks through ingestion, inhalation and dermal contact of soil were calculated for children and adults.The average values of Cr, Ni, Cu and Zn in soil of Dukki and Sharigh coal mines were found above the permissible limits recommended by Grade I of Environmental Quality Standard.The results show that highest risk is associated with soil ingestion among children followed by adults. The highest risk through ingestion (HQing) was observed for Cr (5.31E-02 for adults, 4.58E-01for children) in Dukki coal mines and lower was found for Zn (4.63E-08 for adults, 1.56E-07 for children) in Sharigh coal mines. The values of HQ were found less than one which show that adults and children are experiencing non-carcinogenic effects.Carcinogenic risk for Cr was found1.03E-02 (for adults) and 1.04E-02 (for children) in Dukki coal mines while in case of Sharigh coal mines, carcinogenic risk was 6.77E-04 (for adults) and 5.77E-03 (for children). The carcinogenic risk for Cr was found higher than permissible limits(1 × 10−6 to 10−4) and found lower for Ni. Therefore, the conditions of Dukki and Sharigh coal mines are unsatisfactory.