Bengaluru: While the contamination and encroachment of hundred-odd lakes in Bengaluru has been a hotly debated topic, there seems to be a much bigger problem and it's quite scary – majority of the rivers in the state are polluted.
Over 655 km length of 15 rivers in 38 spots is highly polluted, says the Monitoring of Indian National Aquatic Resources System (MINARS), which is a part of the Central Pollution Control Board (CPCB). These rivers are polluted three to 10 times more than the permissible limit.
MINARS, which conducted the tests through its 61 monitoring centres across the state, has reported that Biochemical Oxygen Demand (BOD) – which determines the pollution levels in water bodies – ranges from 3-10mg/L, while the prescribed level for unpolluted rivers is less than 1 mg/L.
This decline in the quality of water has affected productivity in many terrestrial and aquatic ecosystems and has led to a loss of biodiversity in these rivers.
Cauvery, Arkavathi, Bhadra, Bhima, Ghataprabha, Kabini, Kagina, Kali, Krishna, Lakshmantirtha, Malaprabha, Manjira, Shimsha, Tungabhadra and Tunga rivers have been polluted. These rivers are classified under category IV (BOD level between 6-10 mg/L) and category V (BOD level between 3-6mg/L) of the CPCB monitoring list.
These rivers are polluted most near cities and towns, and the CPCB has identified 24 urban centres along these rivers that have contributed to pollution. The CPCB estimates that on an average, a population of 50,000 people generates around 38,000 million litres of wastewater every day, while the municipal waste water treatment capacity is just 11,000 mld across the country.
Poor environment management systems in industries, such as chemicals, metal and minerals, leather processing and sugar mills, have led to discharge of highly toxic and organic waste water, the CPCB stated.
S. Shanthappa, Member Secretary, KSPCB told Deccan Chronicle, "We have directed departments concerned to maintain water quality and not to discharge sewage wastes into the rivers.”
Former Environment Secretary, Dr A.N. Yellappa Reddy, said that issuing orders alone won't solve this massive problem. “The CPCB should ask municipalities to set up sewage treatment plants. Gram Panchayats should be told to flow waste water into wetlands, which can be created by occupying land and making provisions to trap sewage waste. KSPCB should make use of good consultants to prepare detailed project reports to mitigate river pollution. They should also make use of river action funds by the centre and engage competent people to find solutions.”