Pharmaceuticals ranging from painkillers to synthetic estrogens can harm aquatic life when they enter waterways through human excreta, hospital and household waste, and agricultural runoff. Now, researchers have shown that there’s another way for such drugs to get into the environment: A treatment plant in India that processes wastewater from pharmaceutical manufacturers discharges highly drug-contaminated water into a stream that feeds a major river.
The treated water contained astronomical amounts of antibiotics, along with high concentrations of analgesics, hypertension drugs, and antidepressants.
Production facilities “have not been considered an important source of drugs in [the] environment,” says lead author Joakim Larsson of Göteborg University in Sweden. “This is not the case in India. We found levels of drugs many orders of magnitude higher than anywhere [recorded] on Earth before.”
Larsson and his colleagues collected water samples from the effluent of a treatment plant that cleans the wastewater of 90 bulk-drug manufacturers in Hyderabad in southern India. The region produces most of India’s pharmaceuticals, 60 percent of which are exported. The treated effluent pours into a stream that eventually joins the Godavari, India’s second-largest river.
Of the 59 compounds for which researchers screened, 21 were present in concentrations greater than those typical of drugs in effluent from U.S. sewage-treatment plants, about 1 part per billion (ppb). Eleven of the drugs, including six antibiotics, had concentrations higher than 100 ppb. One of them, the common broad-spectrum antibiotic ciprofloxacin, registered at about 30,000 ppb. An antidepressant that belongs to a class of drugs known to disrupt hormone effects in fish (SN: 6/17/00, p. 388) was at a concentration of 800 ppb.
The results appear online and in an upcoming Journal of Hazardous Materials.
Beyond studies of gender effects in fish, little research exists on the possible health effects on people and other animals of pharmaceuticals in the water supply. However, Larsson points out that the amount of antibiotics that his team found was well above that known to affect a variety of organisms, including plants, bacteria, and blue-green algae (SN: 6/29/02, p. 406). “There is no doubt” that concentrations found in the study are toxic, he says.
Following common practice, the treatment plant in India mixes raw human sewage with contaminated waste to enlist the decomposing capacity of bacteria in the water cleanup. The enormous quantities of antibiotics in the wastewater might not only reduce the effectiveness of that process but also encourage the development of antibiotic-resistant bacteria, Larsson says.
“We do find pharmaceuticals routinely in wastewater effluents,” says Dana Kolpin, a hydrologist with the U.S. Geological Survey in Iowa City, Iowa. The concentrations recorded in the study are “certainly significant,” he says. Sampling incoming waste and the sludge remaining after treatment, he says, would clarify what quantities of drugs are getting into the environment.
Daniel Schlenk, an ecotoxicologist at the University of California, Riverside, notes that many of the drugs measured in the new study are water soluble and are more likely to be diluted and washed away than to accumulate in aquatic organisms. Even so, the extremely high concentrations recorded “could still be a problem,” he says.