Payesh (Jan 2005)
Quality of drinking water in a municipality district in Tehran
Abstract
Objective(s): To examine the sanitary quality of drinking water in 17th municipality district in Tehran. Methods: 210 tap samples were collected over a period of 6 months (From summer to winter, 2002-03) and analyzed for bacteriological parameters; 22 samples were analyzed for physiochemical parameters. All laboratory analyses were conducted by the contract laboratory and followed the procedures outlined in the 19th edition of standard methods. Parameters assessed were temperature, pH, turbidity, TDS, EC, hardness, alkalinity, anions, cations, total coliform count, thermo-tolerant coliforms, heterotrophic bacteria and residual chlorine. Also, the associations between the parameters were analyzed using statistical tests. Results: The results show that water in this area of Tehran contains calcic bicarbonate and sodic bicarbonate, and its overall quality is good. Based on guidelines from the world health organization (2003) and the institute for standards and industrial research in Iran, the quality of drinking water in the 17th district is considered to be good. The results of statistical analysis indicated that there was a positive significant correlation between residual chlorine, total hardness, permanent hardness, Ca2+, Mg2+, turbidity, No3- and seasons of sampling. Such positive association was also observed between residual chlorine and station of sampling. Results also showed that the sampling station had no significant impact on mean values for turbidity, EC, TDS, hardness, alkalinity, anions and cations. In addition, no significant correlation was detected between turbidity and total coliforms or between pH and total coliforms. Conclusion: There is a positive significant correlation between residual chlorine and total coliforms. Also there is a positive significant correlation between EC and TDS according to equation: TDS=(0.55-0.7) EC.
