Analysis of environmental isotopes and their application for treating sewerage pollution in the selected area of Rawalpindi (T-1292) (MFN 3878)

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.