Abstract:
Fresh water resources of Pakistan are being deteriorated in terms of quality and quantity and the effects are being promulgated due to over population and climate change. The inhabitants of Islamabad generally consume drinking water from community sources such as filtration plants, tube wells and household sources such as bore wells, tap and bottled water. This study aimed to assess the health risk related to toxic elements (Pb, Cd, Ni, Zn, Fe and As) in these drinking water sources ofIslamabad by determining the average daily dose (CDI) and Hazard Quotient (HQ) for drinking water and by dermal exposure estimations for surface water. Toxic elements in drinking water samples were analyzed using atomic absorption spectrometer and statistical analyses such as correlation analysis, Principal Component Analysis (PCA) and cluster analysis were applied on the data. Furthermore, health survey was administered with 500 households within the study area to assess demographics, drinking water consumption patterns, awareness level and commonly faced water borne diseases. Spatial variation oftrace elements was depicted through spatial distribution maps. Calculations of Health risk showed that Chronic Daily Intake (CDI) and Hazard Quotient (HQ) were found in the order of As> Pb > Cd > Zn, Fe> Ni for tube wells, As > Pb > Zn > Fe > Ni for filtration plants, As> Zn, Fe> Pb for bore water, As > Pb > Zn > Cd > Fe > Ni for tap water. Moreover, the trace elements were also detected in various bottled water brands. The HQ value of all the detected elements were found below the acceptable drinking water limit indicating no health risk to local population. Similarly, exposure estimation for dermal contact via surface water (Simli dam, Khanpur dam and Rawal dam) also showed no immediate health risk. Health risk questionnaire revealed that diarrhea was the most common water related issue being faced by local population and large proportion of the population depend on filtration plant for their daily water intake. The study concluded that microbial contamination was the main water quality issue of Islamabad instead of trace element pollution.
