SEATTLE — When road salt gets into waterways the zooplankton are the ones that get pummeled.
Zooplankton are invertebrates and they’re a very important part of the food chain. Bugs and fish eat them. Frogs eat the bugs and so on up the ladder. Without these little guys, ecosystems can collapse.
But the effects of road salt aren’t limited to zooplankton. When you put salt on a road it doesn’t just disappear with the snow and ice.
Chloride is a component of salt that sticks around. A study from 2005 showed that chloride levels are on the rise in drinking water in several Eastern states. Chris Swan, an associate professor at the University of Maryland and an expert on river ecology, says that could cause problems.
“Are we going to end up salinizing our freshwater and is it going to cost us money in the long term, in order to fix that?” Swan asks. “That would be a serious concern.”
But is that a concern in the Northwest, where less road salt is used?
“No, that doesn’t necessarily translate out here,” says Mike Means, the water quality section manager at the state Department of Health. Means says much of the water supply for urbanized parts of the state comes from protected areas where roads are not salted like they are in cities, so salt contamination isn’t a concern.
“In general, from applying salt in Seattle, we probably won’t see it at all ever in the water supplies,” he says.
The Department of Health requires municipalities to test for chloride levels in drinking water every three to nine years.
The Washington Department of Ecology hasn’t conducted any research on the impact of road salt on animals.
Officials from the state Ecology and Health departments say there’s not enough evidence in the Northwest to give government officials pause about using salt to keep winter roads safe.