A month ago, Rajasthan health card found Sambhar Lake to be highly polluted
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, Bikane, 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 kilometer lake in Jaipur and Nagaur districts, said the death toll has risen to 15,665 since November 10, when first dead birds were spotted. A total of 5,665 carcasses were found in the two districts, a government statement said.
The health card found that Sambhar, India’s biggest inland salt-water lake spanning 24,000 hectares, had have 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.
“BOD is one of the indices that reflect the water quality,” said Dr S Murlidharan, senior principal scientist at Salim Ali Centre for Ornithology and Natural History (SACON) in Coimbatore. “High BOD means bad water quality primarily because of invasive living organisms living in water,” he added.
Hyper salinity, said an expert at the Bikaner lab, is an indicator that the water is prone to bacterial growth.
High BOD, hyper salinity and high pH value of water are all indicative of rampant pollution around the lake, said experts. “This means the state pollution control board has failed to control illegal activities in the lake even after a strong order by the National Green Tribunal (NGT) in 2017,” said environmental activist Babu Lal Jajoo.
The tribunal, taking note of wetland authority reports by Vinod Kapoor in 2010 and by National Environmental Engineering Research Institute (NEERI), Nagpur, in 2016, which pointed at high pollution levels in the lake, directed the Rajasthan government in November 2016 to stop all illegal commercial activities around the lake.
The State Wetland Authority was told to consider recommendations of these two expert committees, but the authority constituted in 2018 to examine them have not met even once, a Rajasthan government official, who was not willing to be quoted, said, adding that the approval to non-official members of the authority was still pending.
“As the first activity of newly established Directorate of Environment and Climate Change, the health cards were prepared in coordination with our knowledge partner, The GEER Foundation, Gujarat. The outcomes have been submitted to MoEFCC where detailed analysis is being done,” said Monali Sen, director of the state DoECC.
“While we wait for MoEFCC instruction we are working to prepare conservation plan for the wetlands as per the report,” she added.
The health card also pointed out to key procedural lapses at Sambhar salt wetland. The wetlands rules, 2010, under the Environment Protection (EP) Act, say that every wetland should have a wetland map, a management plan, and the wetlands need to be notified through the State Wetland Authority. Sambhar has none of these - state government officials said.