A study by chemistry professors and students from Bhavan’s College in Andheri found that the concentration of heavy metals in a pond inside the college campus was more than the permissible limit set by the World Health Organisation (WHO). The study, conducted between June 2011 and May 2012, found a significant presence of carcinogenic heavy metals such as lead, mercury and arsenic in the aquatic life and vegetation in the pond.
The study will be presented on Saturday at the ongoing Green Health International Conference in the city.
The study found that the average concentration of lead in the fish samples was 0.05 parts per million (ppm) which was above the maximum permissible limit of 25 parts per billion set by the WHO. The concentration of other heavy metals was also high (see box). These metals could damage the gastro-intestinal tract after the consumption of fish.
There was a great deal of accumulation of heavy metals in the Indian Carp (Catla) and in the vegetation inside the lake such as mangroves, said the study. “We found that the concentration of metals in mangroves and plants had slowed their growth. We have also observed discolouration of leaves,” said Pravin Shingare, assistant professor, chemistry department, Bhavan’s College.
He added that mercury in its inorganic form is absorbed in the gastro-intestinal tract, while high concentration of copper in plants can damage roots.
“Even a small concentration of heavy metals such as mercury and arsenic can be harmful. Since the readings of concentration of metals in the fish are consistent over a year, it shows that toxicity is constant in this species,” said Shankar Gajbhiye, chief scientist, National Institute of Oceanography.
“Though the study was not done in a flowing water body, the concentration of metals is high,” Gajbhiye added.