The water quality at the Point Calimere Wildlife Sanctuary might be unsafe for avifauna to feed and breed, notes a study that examined different pollution indicators in water. Researchers from Bharathidasan University, Tiruchirappalli compared their results with the Central Pollution Control Board (CPCB) and the United States Environmental Protection Agency (USEPA) standards to reach this conclusion.
The wildlife sanctuary located in Nagapattinam district of Tamil Nadu spreads across an area of 30 sq.km and comprises sandy coastal, saline swamps and thorn scrub forests around the backwater. Though it is a protected area and a Ramsar site, chemical companies and small-scale shrimp farms around the wetland have started to pose a threat to the biodiversity and ecosystem of the sanctuary.
A total of five sampling sites in the sanctuary were chosen for the study. Temperature of the atmosphere and water, and water quality analysis were carried out during the peak bird breeding season.
Atmospheric temperature at a few stations exceeded 36-40 degrees Celsius. “This can affect the egg albumen during the pre-incubation period, thereby providing better growth conditions for harmful microorganisms in the eggs,” says the report published in Marine Pollution Bulletin.
The pH and salinity of the waters also exceeded the permissible limits for ecologically sensitive zones. Previous studies have shown that high acidic or high alkaline water can affect the metabolic and developmental activities of wild animals and birds.
“There are many salt pans near the sanctuary. This could be increasing the salinity. The chemical companies are also letting out untreated effluents into the waters. All this can have a deteriorating effect on the ecology,” explains Rajendran Viji, research scholar at the university and first author of the paper. “Previously we used to see thousands of migratory birds, now the numbers have gone down to a few hundreds. The birds are starting to avoid the sanctuary.”
Microbial indicators such as coliform bacteria were also found to be very high at all the five sites. The faecal waste of the birds contains a high level of microbial load besides nitrogen, and this can significantly alter the nutrients in the water. Previous studies have shown that drinking the contaminated water can lead to deformities in birds. Coliform infections in the birds have also been reported to cause a change in their natural behaviour and even affect their long distance migration.
“There are also high chances for the prevalence of antibiotic resistance among the coliform bacteria and we are planning to do more investigation on this,” says Lt. Dr. Shrinithivihahshini N.D, from the Department of Environmental Management at Bharathidasan University and coauthor of the paper. “Strict environmental regulations should be imposed and salt pan and other aquaculture practices around the sanctuary should be prohibited. Eco-tourism is also causing disturbances in this area.”
