ENVIRONMENTAL GEOCHEMISTRY OF ATTOCK AND HARIPUR BASINS, PAKISTAN

Abstract

The purpose of this work was to investigate the environmental geochemistry of Attock and Haripur basins of Pakistan; using water, soil and plants as indicators. The study included determination of seven physiochemical parameters (pH, TDS, EC, NO3-, SO42-, Cl- and HCO3-) along with the monitoring of 15 major and trace elements (Na, K, Ca, Mg, Cd, Cr, Cu, Pb, Fe, Ni, Zn, Co, Mn, As and Hg) concentrations and these were analyzed through atomic-absorption spectrometer and inductively coupled plasma mass spectrometry (ICP-MS). Data presentation and interpretation were done by employing a range of statistical tools like Piper diagram, chronic daily intake, hazard quotient and also by applying multivariate analysis (Principal component analysis, Correlation, Cluster analysis). The GIS based spatial distribution of samples and parameters were analyzed using ArcGIS 9.3. The physico-chemical parameters of water were compared with those of WHO (2008) and USEPA standards. Piper diagram showed that 80% and 90% water samples of Attock and Haripur basins respectively fell in the field of Ca-Mg type on the basis of cations and HCO3- type on anion basis. Chronic daily intake (CDI) and hazard quotient (HQ) were also calculated. HQ was <1 for all the heavy metals (HMs) suggesting no risk to health. Application of different multivariate techniques for the interpretation of the metal data obtained during the monitoring program revealed that geogenic and anthropogenic activities were major sources of water contamination in the study area. Fourteen elements (Na, K, Ca, Mg, Cd, Cr, Cu, Pb, Fe, Ni, Zn, Co, Mn and As) were analyzed in soil samples and were compared with that of the normal agricultural soils. Most of the metals showed random distribution with diverse correlations in both basins. Principal component analysis and cluster analysis revealed significant anthropogenic intrusions of HMs in the soils. Geoaccumulation indices values of As, Na, Ca, Pb and Cd indicated moderate to heavy contamination. Rest of the elements (Co, Cr, Cu, Fe, K, Mg, Mn and Zn) revealed practically no contamination in the studied soils. The spatial distribution of HMs of soil showed high concentration near the industrial areas while major cations concentrations were high near the agricultural areas. Vegetables, cereal and their respective soil samples were analyzed for As, Cd, Cu, Ni, Pb, Mn, Cr and Zn by ICP-MS. All toxic element concentrations in the edible parts of leafy vegetables were higher than non leafy vegetables and, also, higher than the FAO/WHO recommended limits. The risk assessment of HMs through consumption of vegetables suggested that Health risk index (HRI) values for adults and children were higher than the safe limit (>1) with exception of Cr (<1); therefore, the health risks of all elements through the consumption of vegetables were of great concern in the study area. Nine HMs (Zn, Cu, Cr, Ni, Co, Cd, Pb, Mn and Fe) were analyzed in medicinal plants. Their HMs concentrations were high according to the international safety standards for the consumption of human beings. High level of HMs in the medicinal plants could be due to the industrial and agricultural activities in the study area. It is concluded that water and soil quality of the Attock and Haripur basins are facing severe degradation due to unwise industrial activities in the study area. This study will, therefore, provide basis for the future management of other polluted streams and soils of the regions. The quality of ground and irrigation water can be improved by implementing national quality standards and installing proper treatment plants in the industries. Key words: Haripur Basin, Attock Basin, Groundwater, Soil, Vegetable, Medicinal plant