Heavy metals contamination in surface and groundwater supply of an urban city.

There is a continuous increase in the demand of water supply in cities due to the industrialization and growing population. This extra supply is generally met by groundwaters or nearby available surface waters. It may lead into incomplete treatment and substandard supply of drinking water. To ensure that the intake water derived from surface and groundwater is clear, palatable, neither corrosive nor scale forming, free from undesirable taste, odor and acceptable from aesthetic and health point of view, the final water quality at Delhi have been evaluated. The final water supply of four treatment plants and 80 tubewells at Delhi were surveyed in 2000-2001 for cadmium, chromium, copper, iron, lead, manganese, nickel, selenium and zinc. The levels of manganese, copper, selenium and cadmium were found marginally above the Indian Standards (IS) specification regulated for drinking water. The data was used to assess the final water quality supplied at Delhi.