Evaluation of heavy metal ions in the groundwater samples from selected automobile workshop areas in northern Pakistan

Abstract

Automobile workshops can be found in many places in Pakistan and most of them are located near the residential areas. Some activities in automobile workshops can release heavy metals, having the adverse impacts for human health. Islamabad and Rawalpindi are twin cities in northern Pakistan where automobile workshops have been operated almost forty years and have never been studied their impact on the surroundings. Therefore, there is a need to identify heavy metal contaminants in the groundwater to avoid the health hazards. This research aimed to evaluate the heavy metal contaminants in the groundwater samples from thirty selected locations points near automobile workshops. The physicochemical properties including pH, electrical conductance (EC), total suspended solids (TSS), total dissolved solids (TDS), and the concentrations of anionic (F− and Cl−) and several heavy metal ions were assessed. The pH and TDS values of almost all samples were within the permissible limits. The EC values were ranging from 0.79 to 1.80 μS/cm with an average value of 1.12 μS/cm while the TSS values were ranging from 210 to 620 mg/L with an average value of 431.3 mg/L. Several samples had higher level of F− ions and several others had free of F− ions. The concentrations of Cl− ions were below the permissible limits. Almost all heavy metal ions such as Ni2+, Co2+, Zn2+, Pb2+, Cr3+, Cd2+, Fe2+ and Mn2+ were obtained in higher concentration than the permissible limits, except for As3+ ions. Besides, the existing of one metal has correlation with other metals. In future, the rapid, green, facile, and new method to remove or adsorb the heavy metal ions from groundwater or other environmental water samples can be investigated for large scale production.