Fish Exposed to Wastewater Absorb Many Medications Meant for People

One fish, two fish, Zoloft in bluefish?

Evidence that fish are being contaminated by pharmaceuticals introduced into wastewater keeps building. That's clear as scientists look beyond drug levels in bodies of water and directly measure concentrations in the blood of fish that swim there, as one team undertook for a new study published July 26 in the journal Environmental Pollution. While experts say human health isn't at risk, unknowns remain, given the increases in pollution levels as the population grows.

For some drugs in the study, blood concentrations that would be high enough to treat a human were seen in comparable levels in fish – albeit in proportion to their much smaller body sizes and blood volumes – likely affecting them as well. Metformin, a widely used and inexpensive medicine for treating diabetes, helps millions of Americans keep their blood sugar under control. However, metformin was one of the drugs found in significant levels in fish.

Antibiotics to fight infections, drugs to ease depression, statins to keep cholesterol in check and blood pressure medications to prevent heart attacks and strokes – while useful for people who need them – offer no benefits to the fish exposed to them. For any drug, a measure is available indicating the concentration needed in the blood to have a therapeutic effect for humans. "We can measure that in fish," says lead study author James Meador, an environmental toxicologist at Northwest Fisheries Science Center in Seattle, part of the National Oceanographic and Atmospheric Administration, a federal agency...