MONITORING OF GROUNDWATER POLLUTION STATUS IN PERI-URBAN AREA OF ISLAMABAD WITH ON-SITE SANITATION (OSS) FACILITIES

Abstract

Groundwater contamination from On-Site Sanitation (OSS) Systems poses a significant threat to the safety of millions of individuals living in peri-urban areas worldwide. In this context, a study was conducted in five peri-urban areas of Islamabad categorized as areas with pit latrines and areas with septic tanks, to investigate the impact of OSS on groundwater quality, impact of seasonal variation and to evaluate the water quality index of the groundwater samples. The findings revealed widespread contamination of E.coli in all groundwater samples having concentrations >23 CFU/100 ml. Moreover, helminths eggs were identified in groundwater samples from both sets of locations.

xv Results showed hardness levels exceeding the World Health Organization (WHO) standard of 500 mg/L in areas with pit latrines. Increased concentrations of Chemical oxygen demand (COD) in samples predominantly from regions with pit latrines was observed during wet season. Similarly increased concentrations of Ammonium-N were observed in areas with pit latrine as compared to the areas with septic tanks. Overall results demonstrated higher pollutant concentrations during wet season compared to dry season. The WQI revealed groundwater to be ‘unfit for drinking’ for 100% of the samples during wet season and approximately 45% samples during dry season. The field survey indicated that people in areas with pit latrines were unaware of basic OSS maintenance practice and were found to be consuming untreated groundwater. Hence this research underscores the need for improved sanitation practices, awareness campaigns, and water treatment initiatives to safeguard groundwater quality and public health in peri-urban areas affected by OSS contamination.