Detection of Hazardous Contaminants in Ground WaterResources: An Alarming Situation for Public Health inKarachi, Pakistan

Due to industrialization and over population,surface water resources are out of reach from manypeople so consumption of ground water is the only choice to overcome the water scarcity.Naturally, ground water is one of the significant and potable water resource but some geographicalconditions and anthropogenic activities deteriorate the water quality and make it objectionable fordrinking. This study was conducted to evaluate the ground water quality of Karachi, Pakistan. Forthis, 42 ground water samples were collected from different districts of Karachi and analyzed theirphysicochemical and microbiological characteristics and compared with both international (WHO)and national (SEQS) drinking water standards. Observations of the study declared that overallcontamination (physicochemical and microbial) in the ground water samples of different districtsof Karachi was as follow West (21%), South (20%), Central (17%), Malir (16%), Korangi (14%)and East (12%). Physical assessment of the study area declaredthat pH and turbidity of the groundwater samples varies in the range of (6.54-7.9) and (0-1.01 NTU) which exist in the standardprescribed limit. Whereas, detection of chemical contaminants particularly TDS (457-12090mg/L), hardness (118.8-3645 mg/L) and chloride (190-4918 mg/L) content in most ofthe sampleswere also exceed from the prescribed limit. Additionally, arsenic was abundantly present rangingfrom 3.52-13.63 mg/Lin all collected samples of Karachi city while the concentration of cadmium(range: 0.0005-0.5012 mg/L) and lead (range: 0.201-1.817 mg/L)were also high in few samples,from the permissible limit of drinking water. Microbial contamination was also detected in whichcoliforms were presentin the range of 0-150 CFU/100mL, which also unfit the water quality. Thisdeteriorated ground water quality of Karachi can be improved by maintenance of proper sanitaryconditions of the communities and implementation of water treatments, otherwise consumption ofsuch water may develop serious health related consequences in the consumers.