Participation in the League’s Winter Salt Watch campaign, which helps people measure chloride levels in local streams, outpaced our inaugural campaign last winter. This winter, the League distributed more than 500 test kits — twice as many as we sent out last winter — to volunteers nationwide.

Why chloride tests? Road salt (sodium chloride) is everywhere during winter months. It keeps us safe on roads and sidewalks, but it can also pose a threat to fish and wildlife as well as human health. Fish and bugs that live in freshwater streams can’t survive in very salty water. And water treatment plants are not equipped to filter out the extra salt, so it can end up in our tap water and even corrode our pipes.

This winter, volunteers from 17 states shared results from more than 339 chloride tests in 40 different watersheds — and more results are coming in every day. The findings confirm an ongoing problem: about 20 percent of samples showed chloride concentrations higher than the maximum safety standard (230 ppm) set by the Environmental Protection Agency for aquatic life.

Road salt is actually a year-round problem. Some of the salt that runs off roads and sidewalks in the winter is absorbed into the ground nearby, where it washes into nearby streams after every rain event. Recent studies show that increased salt levels in streams are even more toxic to aquatic life when water temperatures are warmer. So it’s important to have a baseline (starting point) for chloride levels in the fall and test again after snow and rain events.

To see results from this winter, visit iwla.org/saltwatch.