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.
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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.
