Microscopic organisms that are known to keep a check on the population of various kinds of bacteria and also form an important link in the food chain, have been found to be dwindling at Sanjay Lake in east Delhi.
Researchers from Delhi University, who have been studying these single-cell organisms for the past few years, apprehend their decline would mean that the water quality of Sanjay Lake is deteriorating as these organisms are sensitive to changes in their environment and serve as ‘bio-indicators’.
“We found at least 20 species of single-cell freshwater ciliates in each of the water samples that were collected from the lake between 2012 and 2015 for the research. But when we collected samples in September 2017, we could find only two species. Something is wrong with the water. There is also possibility that the levels of heavy metals are rising. That needs to be analysed,” said Seema Makhija, associate professor of Zoology at Acharya Narendra Dev College.
A team of zoologists from Delhi University and National History Museum in London led by Makhija was conducting a research to assess how these single-cell organisms inhabiting Delhi’s water bodies respond to the rise in the levels of concentration of heavy metals such as copper, cadmium, nickel, lead and zinc in the water. The research has been already published in ‘Current Science’ a peer-review journal in its latest edition.
Water samples were collected from three different water bodies in Delhi including the Sanjay Lake in east Delhi, Raj Ghat and Okhla Bird Sanctuary. Even though the quality of water at Raj Ghat and Okhla Bird Sanctuary did not deteriorate, scientists have found signs that the water at Sanjay Lake is turning fouler.
“If the food chain collapses, many aquatic animals and fishes could die and would ultimately be wiped out from the lake. The rise in bacteria could have serious ecological and public health implications in the future,” said Komal Kamra associate professor of Zoology at Sri Guru Tegh Bahadur Khalsa College.
Locals pointed out that solid waste, including plastic, are often dumped in the lake and its surrounding areas which might be deteriorating the water quality.
A senior official of the Delhi Development Authority said that a private organisation has started a pilot project to clean the water of Sanjay Lake and Hauz Khas.
The Waste Atlas 2014, a compilation of data on the 50 biggest dumpsites of the world, had warned that the Ghazipur dump could be a potential source of pollution, as it is located just 2.5 km from Sanjay Lake. Leaching of pollutants and chemicals from the dumping site is also possibly affecting Yamuna’s water.
“A similar research to find out the population of these microorganisms in the River Yamuna is now underway. The project has just taken off and would continue over the next two years,” said Kamra who is leading the Yamuna research.
Water samples from five points, including Cullak Pur, Wazirabad, Nizamuddin, ITO and Okhla, have been collected. They are now being analysed in laboratories. The team would be collecting samples from the same locations every year over the next two years before coming to any conclusion.
