DRINKING WATER QUALITY MONITORING WITHIN A DISTRIBUTION NETWORK: F-8 AND E-7 SECTORS OF ISLAMABAD

Most pollution of drinking water is caused by inadequacy of distribution system, by inefficient upkeep of the sewage system and by defects in the disinfection processes. This may be the cause of water borne epidemic outbreaks. Concern over the presence of faecal coliform in public drinking water supplies has been expressed in recent years in Pakistan, since it has been regarded as a pathogenic organism, of prime importance in gastroenteritis. It is, therefore, necessary to carry out routine monitoring of the distribution system. The aim of this study was to monitor the quality of water in drinking water supplies at the treatment plant and in the water distribution network of two major sectors, F-8 and E-7, of Islamabad, Pakistan. The drinking water distribution systems were monitored, over the period of one month, to assess the microbial water quality and residual chlorine. The drinking water quality monitoring was performed by collecting samples from the water source and residential taps from each distribution network. The samples were analyzed for physico-chemical indicators (temperature, pH, conductivity, total dissolved solids (TDS), turbidity, total chlorine, free chlorine residual and chloramines) and bacterial indicators (total and faecal coliforms). In the sector F-8, temperature ranged from 19.6°C to 22.6°C, TDS varied between 156.0 mg/L and 268.0 mg/L, turbidity ranged from 2.70 to 8.15 NTU, pH varied from 6.96 to 7.48, conductivity ranged between 325 and 548 S/cm, total chlorine observed varied between 0.14 mg/L and 0.21 mg/L, total coliforms ranged from undetectable level to 2.2 most probable number (MPN)/ 100 mL. In sector E-7, temperature ranged from 20.4°C to 21.7°C, TDS varied between 157.4 mg/L and 163.2 mg/L, turbidity ranged from 1.30 to 4.46 NTU, pH varied from 7.26 to 7.65, conductivity ranged between 328 and 339 S/cm, total chlorine observed varied between 0.40 mg/L and 1.00 mg/L, total coliforms ranged from undetectable level to 16.1 most probable number (MPN)/ 100 mL.