25 Dec : Bacterial contamination of water bodies occurs mainly due to the discharge of untreated domestic wastewater from urban centres. Other non-point sources such as in-stream bathing, open defecation near banks, dead body dumping, cattle washing etc also contribute to the bacterial contamination. This is also affected when the recipient water bodies do not have sufficient fresh water flow for dilution.
Bacterial contamination is measured in terms of counts of Coliform group of bacteria of fecal origin. The maximum permissible limit and desirable limits for fecal coliform count for bathing waters has been notified as 2500 Most Probable Number (MPN) per 100 millilitre (ml) & 500 MPN/100 ml respectively. As per CPCB’s data, the fecal coliform count is reported to be more than 2500 MPN/100 ml in 15.7% of water samples, between 500 & 2500 MPN/100 ml in 18.3% samples and less than 500 MPN/100 ml in 66% samples during the year 2007. The same, thus, is observed to comply with the standards in more than 66% of water samples. As per this data, Mahi, Subernarekha, Pennar, Beas, Baitarni & Narmada, are some of the rivers found to be relatively clean with fecal coliform levels meeting the maximum permissible limits. In selected stretches of Yamuna, Kali, Hindon, Damodar,Tons, Ganga, Satluj, Gomti, Sabarmati, Krishna, Godavari, Cauvery etc, the bacterial levels are found to exceed the permissible limits.
Conservation of rivers is a dynamic activity with an ever increasing pollution load due to increase in population. Review of strategies of conservation of rivers is a continuous process. The Central Government has initiated an exercise for revamping the river conservation strategy to promote a holistic and integrated approach. The proposal for revamped strategy includes among others, focussing on quantity of the river water as much as on the quality, redesigning institutional arrangements at the National and State levels, developing suitable indicators for measuring water quality, integration with urban development plans.
The Central Pollution Control Board (CPCB) along with the State Pollution Control Boards (SPCBs) is monitoring the water quality of rivers and other water bodies at 1365 locations covering 27 States and 6 Union Territories. The monitoring network covers 282 rivers besides a number of lakes, tanks, ponds, etc.
The CPCB had initially carried out the river basin studies of the major rivers in the country and on the basis of these studies, Ganga Action Plan Phase I was launched in 1985 at Varanasi. Subsequently, based on CPCB’s identification of polluted stretches along the rivers, other River Action Plans have been formulated and implemented under the National River Conservation Plan (NRCP), which now covers identified polluted stretches on 35 rivers in 164 towns spread over 20 States.
Besides the NRCP, other centrally sponsored programmes for sewerage and sewage treatment of domestic wastewater include the Jawaharlal Nehru National Urban Renewal Mission (JNNURM) under the Union Ministry of Urban Development.