Abstract:
Ground water is the major source of water supply in Rawalpindi city, the Punjab
province of Pakistan. River Soan traverses Rawalpindi, this river consider to have
polluted water which may flourishes the ground water of the area. In this study an
attempt has been made to study movement of pollutants from sewerage draining
streams to nearby tube wells in the selected area of Rawalpindi. Three stable isotopes
2H, 18O, 13C were analyzed and used to investigate the source which recharges the
ground water. A total of 24 water samples were collected from Soan River and its
surrounding area. Sampling was done during pre and post monsoon season for stable
isotopic analysis. Physiochemical parameters (pH, temperature, dissolved oxygen,
electrical conductivity) were measured at the site. Water samples for isotopic analysis
were collected and stable isotopes were analyzed by using mass spectrometer. The
slope (5.07) and d-excess (-6.75) of pre monsoon water samples clearly shows
evaporation because of less rain where as the slope of post monsoon water samples
(6.94) and d-excess (+5.74) shows recharge of ground water. A total of 16 samples of
the study area show depletion in δ18O values that indicates quick recharge in post
monsoon whereas only 6 water samples show enrichment in δ18O which suggests
slow recharge. Overall 80 % of the water samples show 13C depletion and 20 % shows
enrichment in post monsoon. The depleted value of 13C clearly shows the sewerage
pollution (sediments and organic compounds) of the Soan River and its surrounding
area.
