Pharmaceuticals Pollute the Ganges

Over three seasons, Doon scientists studied the river waters of two cities in the rapidly industrializing Himalayan state of Uttarakhand: Haridwar, where the Ganges enters India’s northern plains from the Himalayas, and Rishikesh, 21 kilometers away. Haridwar and Rishikesh, with a combined population of 400,000, attract an estimated 20 million tourists and pilgrims annually.

In particular, the scientists analyzed the water at its point of entry into the two cities and at sites before its entry into a sewage treatment plant and after sewage treatment. The study could provide useful baseline data for forecasting and evaluating the efficiency of future antipollution measures of the river basin restoration program, the authors added.

“Compared to previous studies that analyzed samples along various locations along the Ganges, this is the first comprehensive, intensive study in a particular city along the river,” said Surendra Suthar, an associate professor at Doon University and one of the study’s authors.

PPCP concentrations near the cities varied, with the highest measured concentration being 1,104.84 nanograms per liter. Researchers found higher PPCP concentrations at the lower, more populated reaches of the river. The concentrations, especially of anti-inflammatory drugs and antibiotics, were also higher in winter, possibly because of decreased biodegradation associated with lower temperatures and inadequate sunlight, the report said. The study also showed that PPCPs in the region were associated with a higher risk of algal blooms and a moderate risk to the health of river fish.

“The high load of PPCPs during summer and winter could be attributed to the excessive tourist visits for recreational activities and spiritual congregations during these seasons,” according to the report, to be published in Chemosphere in April.

Paucity of Studies

There are few studies on PPCPs in Indian rivers. “Such studies are expensive, as they require sophisticated instruments,” Suthar explained.

“Sewage, treated or untreated, flowing into the rivers is the main polluter,” said Keshava Balakrishna, a professor in the Department of Civil Engineering, Manipal Institute of Technology. Sewage and effluent have long been associated with chemical pollution, as people flush medicines, cosmetics, and hygiene products down the toilet or throw them in the trash. The waste ends up in water treatment plants and landfills and then makes its way into water supplies such as the Ganges.

“Aquaculture, agricultural farms, and pharma industries can be other important sources,” Balakrishna added.

In 2020, Balakrishna’s team reported the presence of PPCPs in two tropical rivers in southwestern India, the Swarna and Netravati, which empty into the Arabian Sea.

A 2017 review by a team of scientists including Balakrishna in Ecotoxicology and Environmental Safety found higher levels of pharmaceuticals in Indian water treatment plants compared with developed countries. The review also pointed out the paucity of studies in India on the fate of pharmaceutical products in water bodies and their impact on human health, “despite India being one of the world leaders in pharmaceutical production and consumption.”

The 2017 review reported that studies from other countries indicated that PPCPs in rivers could accumulate in aquatic organisms and enter the food web. Antibiotic resistance among microbes is the main threat to human and ecological health, Balakrishna said. “Low doses of antibiotics in a river can be consumed by pathogens in the river, [which then] become superbugs, and multiply.”

Suthar, too, cautions about both toxicity in the food web and the emergence of antibiotic resistance in pathogens contaminating river waters. “If we add up all the individual contaminant levels for 1 liter of water, the collective dose will be very toxic, especially if they bioaccumulate in organisms, including some rare species in the Ganges such as the Ganges dolphins,” he said. “And microbes in the waters will become resistant to the drugs.”

A 2019 global review of PPCPs in rivers reported that “no global legal maximum environmental concentrations exist for pharmaceutically active compounds,” despite poor understanding of the combined acute and chronic effects of PPCPs on flora, fauna, and human health.

The global review went on to say that primary and secondary wastewater treatment plants “generally are unable to remove these pollutants, leading to their migration into drinking water supplies,” and recommended advanced tertiary water treatment processes, such as oxidation and adsorption. It also suggested advanced methods for accurate and continuous monitoring of pharmaceuticals in the environment and strict regulations for effluent release.

In India, most antipollution efforts are directed at surface water treatment and focus on parameters such as chemical oxygen demand, biological oxygen demand, nitrates, and bacteria, said Suthar. “We need a policy that looks at PPCPs too.”

Chemical Footprints

The source of the Ganges is the Gangotri Glacier, high in the Himalayas less than 200 kilometers from Haridwar. The recent findings on PPCPs in the Ganges add to research documenting chemical and microplastic pollution throughout the mountain range, including the world’s highest peak, Mount Everest, said Kimberley Miner, a scientist at NASA’s Jet Propulsion Laboratory in California and a research assistant professor at the Climate Change Institute, University of Maine. “Our team found PFAS [polyfluoroalkyl substances], DDT [dichlorodiphenyltrichloroethane], and toxic metals on the mountain, suggesting that the chemical footprint left by trekkers may be as large as the visible trash and pollution footprint.”

The new Ganges research also echoes recent studies tracing PPCPs on European glaciers, where researchers traced chemical pollutants to the use of perfumes in personal care products like soap. Perfumed soaps and ointments are also associated with PPCPs in Haridwar and Rishikesh, where mass bathing events are part of tourism and pilgrimage activities.

This story originally appeared in Eos and is republished here as part of Covering Climate Now, a global journalism collaboration strengthening coverage of the climate story.