A preliminary study of animal life in the Ganga conducted in 2002 has shown that there has been no significant improvement in the number of zooplankton in the river since 1996 despite the efforts of the Indian government to improve the quality of water.
The study, conducted by Mohammed Omair, Michael Wiley, Bernard Naylor and Sudhakar Reddy from the University of Michigan, and Ravindra Sinha and Gopal Sharma from Science College, Patna, appeared in the Winter 2005 issue of The Journal of the International Institute.
"The river is affected by sewage, pollution and deforestation," said Omair. Among other things, the Haridwar Tuberculosis Hospital releases untreated effluents into the river, and thousands of idols coated with paint containing mercury and lead are dipped in the river during festivals.
The scientists found that the concentrations of mercury were 40 times and that of lead nine times higher than the permissible levels. The phosphorus concentration was also extremely high.
Besides pollution, earlier studies have also shown that some insects and plants in and around the Ganga also harbour cholera bacteria.
Omair said that one student, Carrie Knowlton, who collected samples last July also found that 23 percent of the zooplankton had tumours, a sharp rise from two percent in 1996.
Omair said he had no theory that could explain this rise. "This is a worldwide phenomenon, not just the Ganga," he said.
Despite the enormous ecological stress on it, the Ganga continues to support aquatic life -- enough to maintain a food chain -- but if the zooplankton died out, almost all aquatic life, including fish, would also disappear, the study said.
The study fell short in some areas, given that water samples were not always taken at the same locations and because of funding issues, Omair admitted.
But it has helped expand efforts by the University of Michigan's School for Natural Resources and Environment to set up what he called a "biological index" of the Ganga.