Winter is just around the corner, and most jurisdictions are likely preparing to implement their normal practices of using salt and other substances to make roads and other paved surfaces safer. Those safety efforts are deadly to many creatures that are burdened with the runoff from those pavements, according to a US Geological Survey study (co-authored with the Wisconsin State Laboratory of Hygiene) published Sept. 1, 2010, in the journal Environmental Science & Technology.

• "A Fresh Look at Road Salt: Aquatic Toxicity and Water-Quality Impacts on Local, Regional, and National Scales," [2] Steven R. Corsi, [3] 608-821-3835, et al.; USGS press release, [4] Sept. 1, 2010.

A little more than half of all streams studied at 168 monitoring locations in 13 northern cities were toxic for chronic exposure, and 25% were at acute toxicity levels (sometimes more than 11 times higher than the EPA standard). In some areas, including eastern and southern Wisconsin, 100% of the stream-monitoring locations were toxic. For some of the more contaminated areas, adverse effects were still seen in summer. The researchers said they were surprised at the extent of toxicity and the high concentrations of chloride in the streams.

The authors say that their findings indicate that efforts to develop less-toxic methods of keeping roads safe are warranted.