Monitoring of Hazardous Inorganic Pollutants and Heavy Metals in Potable Water at the Source of Supply and Consumers end of a Tropical Urban Municipality

Abstract

River water is not only an indispensable source for irrigation but also plays a vital role for drinking water supply for most of the urban municipalities. Water from rivers is pumped at specific sites and after treatment at municipal water treatment plants supplied as domestic potable water supply. The present study was undertaken to assess the suitability of Gomti river water at Gaughat being used as the source of water supply for Lucknow city and to evaluate post-treatment potable water quality at the consumer end by monitoring the levels of inorganic pollutants (nitrate, nitrite, ammonium and phosphate) and heavy metals. Municipal water supply at Gaughat showed marked variations in the levels of pH (7.13-8.63) and electrical conductivity (375.66-571.67µS/cm). The amount of nitrate, nitrite, ammonium and phosphate was observed 26.25, 0.082, 6.9 and 1.82 mg/l respectively at Gaughat. Also, the levels of heavy metals in the municipal water source at Gaughat varied significantly for Fe (0.33-1.65 mg/l), Cu (0.077-0.108 mg/l), Cd (0.03-0.052 mg/l), Pb (0.68-0.96 mg/l) and Cr (0.036-0.065 mg/l). Water at the user end was also contaminated as the concentration of analysed inorganic pollutants and heavy metals were correspondingly higher than observed at the source. While comparing potable water at the user end of Lucknow municipality with the BIS (Drinking Water Specifications) and WHO standards for drinking water, the concentration of all studied heavy metals and other inorganic contaminants were much above the permissible levels, thus posing a serious threat to the public health.