It is unfortunate that the recent USGS study – a straightforward assessment of chlorides in groundwater areas in 19 states - was spun in a sensational manner in the USGS press release . The press release stated that

Chloride levels above the recommended federal criteria set to protect aquatic life were found in more than 40 percent of urban streams tested. Elevated chloride can inhibit plant growth, impair reproduction, and reduce the diversity of organisms in streams.

The actual report itself is far more sober, as seen in the report summary:

Groundwater-quality data from a sampling of 1,329 wells in 19 states were analyzed. Chloride concentrations were greater than the secondary maximum contaminant level established by the U.S. Environmental Protection Agency of 250 milligrams per liter in 2.5 percent of samples from 797 shallow monitoring wells and in 1.7 percent of samples from 532 drinking-water supply wells.

Of course, a number of newspapers didn't bother to read the report and simply quoted the press release. A careful reading of the report indicates that the 40% of urban areas that showed exceedance of the EPA limit did so only as exceptional events, not as routine discharges from these areas. For instance, the data in the report shows about 1/5th of the Minneapolis samples exceeding the EPA limit. Although regrettable, it can be understood that after particularly intense snow and ice events, the amounts of deicers added to roadways and consequently found in runoff will be greater than usual. We made this case clear to the newspapers that merely referred to the press release.

For decades, the Salt Institute has encouraged and supported a Sensible Salting program to ensure that the level of salt applied to roads is kept to the absolute minimum required to provide the public with the required level of safety and mobility during winter snow and ice events. We have actively supported programs of best practices with the specific goal of minimizing the environmental impacts of deicing and have supported the full and transparent review of these programs to ensure that they are actually working. And they are.

In keeping with our decades-long advocacy of Sensible Salting to reduce the environmental impact of salt application, the Salt Institute has been aware of the potential for intense snow and ice events to demand a large deicer application which could result in an exceptional exceedance, as has been noted in the USGS report. We remain at the forefront of mitigation technology and are currently supported the latest cutting-edge research at Guelph University specifically designed to eliminate the sort of post-event chloride spikes noted in the USGS study.

In addition, the latest science reveals that level of water hardness has a significant impact on chloride toxicity. In areas where the water is harder, chlorides have far less of an impact on the biological organisms than in soft water areas. In fact, most of the northern states have fairly hard water. That is why some of the more progressive states, like Iowa, are beginning to consider the actual chemistry of their waters in order to establish toxicity standards that more closely reflect scientific reality.

Lest this entire issue be taken out of perspective, it must be understood that we have to apply deicers to our roads in winter to ensure safety and mobility. A Marquette University study, demonstrated the unparalleled benefits of deicing with road salts by saving thousands of lives and preventing untold injuries, while allowing our economy and its distribution systems to continue operating during the winter months.

Nevertheless, we must continue to do whatever we can to ensure that the products and services that are employed to allow us to live and work under difficult winter conditions do not compromise the environment for future generations.