Effect of mercury and arsenic from industrial effluents on the drinking water and comparison of the water quality of polluted and non-polluted areas: a case study of Peshawar and Lower Dir.

The purpose of the present study was to find out the sources of mercury and arsenic pollution of water in the industrial area of Peshawar, the capital of Khyber Pakhtunkhwa, Pakistan. Samples of effluents, mud, and water were collected from the target area (industrial area of Peshawar), the area of water supply source, and from the less polluted area, the Lower Dir district, as the control. Hg was determined by the cold vapor generation technique, while arsenic was determined using the electrothermal atomic absorption technique. Data of the water from the industrial area were compared with that of the source area, control area, as well as with the WHO and some international drinking water quality standards. The results show that some parameters, i.e., TDS, DO, pH, and hardness, were more than the permissible limits. Textile and glass industries were found to be the major sources of Hg and As pollution. Downstream dilution of these contaminants was also observed.

Bioaccumulation of metals in human blood in industrially contaminated area.

Heavy metals were analyzed in different foods crops, milk, meat and blood samples collected from different age group subjects such as children (1-12 years), adolescent (12-18 years), adults (18-45 years) and old age (above 45 and 55 years for males and females, respectively) from polluted and relatively less polluted areas. The results revealed that the consumption of contaminated food crops, meat and milk have significantly increased the concentrations of selected metals in the human blood. Cu, Zn and Mn concentrations were significantly higher (p < 0.05) in the blood samples collected from the polluted area as compared to control area. Old people had accumulated high concentrations of metals as compared to the younger ones within the same area. Males accumulated higher concentrations of metals as compared to females.

A comparative study of human health risks via consumption of food crops grown on wastewater irrigated soil (Peshawar) and relatively clean water irrigated soil (lower Dir).

Food crops irrigated with wastewater are mostly contaminated with heavy metals and considered as a main pathway for human exposure. In this study, soil and food crops samples were collected from wastewater irrigated soils, background and relatively less polluted areas. Results of the sequential extraction and total metals concentrations in soils indicated that wastewater irrigation has significantly increased (p > or = 0.001) the bioavailable and total metal contents in wastewater irrigated soil as compared to background and control soils. Heavy metal concentrations in the food crops grown on wastewater irrigated soil were higher than those grown on background and control soils but were found within WHO/FAO permissible limits except for Zn. Health risk index values were less than 1 for both control and wastewater irrigated soils (except Mn). However, the food crops such as Brassica rapa, Spinacia oleracae L., Lycopersicum esculantum, Mentha viridis, Coriandum sativum and Lactuca sativa grown on wastewater irrigated soil can pose health risks because of the high concentration of Mn.