Fish Cannot Smell in Polluted Waters
Fish in lakes tainted with heavy metals are losing their sense of smell.
By Brian Bienkowski and Environmental Health News
“We’ve tested everything from leeches to water fleas to several species of fish,” Pyle said. “Every species and every metal we’ve observed has had effects at low, environmentally relevant concentrations.”
Some metals attack specific neurons in the nostrils that respond to certain smells, Pyle said. Nickel targets the neurons that help fish smell food, while copper – at low concentrations – targets the neurons that help fish avoid predators. At higher concentrations, copper impairs their smell for everything.
“Copper is intensively used as a pesticide, fungicide…It’s found in cars, in boat paint, so boatyards are often contaminated. And it’s often found in industrial discharge and near legacy mining operations. It’s a rare pollutant that’s both agricultural and urban.”
The problem is “likely to be widespread in many freshwater aquatic habitats,” according to a NOAA report. The report said that increases in salmon response time to smells came within 10 minutes of exposure in some cases.
Some pesticides also affect fish smell, including atrazine and chlorpyrifos, according to research by Oregon State University and Canadian scientists, respectively.
