A month ago, Raj health card found Sambhar Lake to be highly polluted
JAIPUR: Just days before the deaths of about 15,665 migratory birds was observed at Sambhar Lake, the Rajasthan environment department’s health card for the lake said its water was highly alkaline, saline, of poor quality, and prone to bacterial growth — pointing to damage inflicted by pollution.
A Bikaner-based lab at College of Veterinary and Animal Science, Bikaner, last Friday said that, on the basis of history, epidemiological observations, clinical symptoms, and post-mortem findings, the most probable diagnosis for the deaths of the birds at Sambhar Lake is avian botulism, a condition caused by a bacterium named clostridium botulinum, which produces dangerous toxins in low-oxygen conditions. On Sunday, the forest department, after conducting combing operations around the 198 square kilometre lake in Jaipur and Nagaur, said the death toll rose to 15,665 since November 10. A total of 5,665 carcasses were found, a government statement said.
The health card found that Sambhar, India’s biggest inland salt-water lake spanning 24,000 hectares, had high levels of salinity, high level of biological oxygen demand (BOD), and about 16% of the wetland area was covered by invasive living organisms. “These are all indicators of pollution in the water,” said S Murlidhar, senior principal scientist at Salim Ali Centre for Ornithology and Natural History (SACON) in Coimbatore.
Under a 100-day action plan for rejuvenation and restoration of 100 wetlands in India, the ministry of environment, forest and climate change (MOEFCC) on August 26 sought ecosystem health cards for six wetlands in Rajasthan – Sambhar, Keoladeo National Park (KNP), Mansagar, Fatehsagar, Pichhola and Udaisagar lakes.
The state’s directorate of environment and climate change (DOECC) submitted the report on October 25. In the report, none of the six lakes got good ratings. The health card had six categories (A+, A-, B+, B-, C+ and C-) and five of the lakes were all rated C-, with KNP in Bharatpur B-.
The Sambhar Lake water was found to be alkaline (ph value more than 7.4), the water’s salinity was found to be more than 40 grams per litre. For salt-water lakes, the desired salinity is between 30 and 40 grams/litre.the BOD level in the lake was found to be between 78 and 203 mg per litre, which is about 13 to 34 times of the permissible limit of 3-6 m/l. Higher the BOD level, lower are the chances for aquatic life to survive.
Hyper salinity, said an expert at the Bikaner lab, is an indicator that the water is prone to bacterial growth.