ASSESSMENT OF SELECTED TOXIC HEAVY METALS IN INDUSTRIAL EFFLUENTS AND DRINKING WATER AND THEIR EFFECTS ON THE VEGETATION AND NUTRITIONAL STATUS OF PESHAWAR

Abstract

The purpose of the present study was to find out the points sources of mercury and arsenic pollution of drinking and irrigation water, their downstream dilution in the industrialized area, Peshawar the capital of Khyber Pukhtunkhwa, Pakistan. Samples of effluents, soil and water were collected from the study area, background area and from the relatively less polluted area the district Dir lower considered as control area. Along with other physicochemical parameters determination of these samples, Hg was determined by cold vapor generation techniques while arsenic was determined by electro thermal atomic absorption technique. The data was compared with the water quality data of background area, control area, national, WHO and some international drinking water quality standards. The results showed that some parameters i.e.TDS, DO, pH and hardness were out of the permissible levels while some are within the range. Arsenic and mercury was determined in nearly all the samples, with higher concentration in the effluents. Textile industries and glass factory were found to be the majors contributing sources of Hg and As pollution. Downstream dilution of these contaminants was also observed. Multivariate and univariate statistical techniques i.e., cluster analysis PCA, regression and correlation analysis, one way ANOVA were applied to the metal data of effluents soil and ground water to point out the contribution of different industries towards the metals pollution, their source identification and distribution. The samples were collected from different industries and different downstream points of the main effluents and from the relatively less polluted area considered as control area. The samples were analyzed for metal concentration levels by flame atomic absorption spectrophotometer. The, metal concentration data in the three media of the polluted area was compared with background data and control data as well as with the WHO safe limits. The results showed that soil has high metals concentration compared to effluents and water. The data also showed elevated levels of Mn and Pb in water that are 8.268 and 2.971mg/L respectively. Principal component analysis along with regression analysis showed that the elevated levels of metals in the effluents contaminate adjacent soil and ultimately the ground water. The other elements Co, Cd, Ni and Cu were also found to have correlation in the three media. xFood 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≥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). Finally, the food crops grown on wastewater irrigated area can cause human health risks in the study area. This study was conducted to investigate the bioaccumulation of heavy metals in human’s blood from different sources. Blood samples were 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 control areas. Forage grasses, meat and milk samples were also collected from the study area. The results revealed that the contaminated forage grasses have led to increase the concentrations of metals in meat and milk. The subsequent uses of meat, milk and food crops were significantly increased the concentrations of trace metals in the human’s blood. This was further supported by correlation and regression analyses of the data. Moreover, Cu, Zn and Mn concentrations were significantly higher (p <0.05) in the blood samples collected from the polluted site as compared to control. Similar trends were also observed between the different age groups within the same area. Old people accumulated high concentrations of metals in their bodies as compared to the younger ones. Similarly, males accumulated higher concentrations of metals as compared to females. The anthropometric data provides valuable information regarding the nutritional status of the people. In order to asses and compare the nutritional status of the people from Peshawar and Dir data was taken for the measurement of Body Mass index (BMI).The BMI values indicated that mostly males and females from both the areas were normal, only a few percent of the people were underweight, very less were overweight and negligible were obese. Comparing the nutritional status based on the BMI xiof the people the males individual from Dir were found healthier than the people from Peshawar. This healthier nature can be attributed to the strong muscular activities, including, farming, labor, etc in the area. Underweight females were also very less in percentage in Dir as compared to Peshawar which may be due to socio-economic conditions of the people. Only 2 % females in Dir were found obese which can be explained in terms of luxurious life due to large families, where work is done by the younger ones allowing the elders just for praying and supervision of the household. The data indicated that the people were of different age, height and weight. Only few dwarf cases were noticed in the individuals from both the areas.