Feb. 11 (Bloomberg) -- Salt used to melt snow on winter roads is making Minnesota’s lakes, rivers and wells saltier, according to a study that may affect regional aquatic life and drinking water.

In findings the University of Minnesota researchers called “alarming,” tests on 39 lakes and three major rivers showed chloride concentrations, or salinity, in Minneapolis-St. Paul area lakes had increased over 22 years. That followed a similar trend in road-salt purchases by the state of Minnesota, which began using the abrasive in the 1950s, the study showed.

The research team led by Heinz Stefan, a civil engineering professor at the University of Minnesota’s St. Anthony Falls Laboratory, said the study was undertaken because nobody had “asked the question of where the salt ultimately goes after the winter season is over.”

Levels of chloride concentration as low as the equivalent of one teaspoon of salt in five gallons of water have been shown to harm aquatic life and drinking water. The Minnesota Pollution Control Agency last year listed five metro area streams as tainted by chloride. Increases in sodium and chloride, the components of salt, have been shown to decrease wetland area biodiversity, alter the development of wood frogs and reduce the number and types of fish.

Britain, suffering from the worst winter weather in 17 years, last week said salt used to keep its roads ice-free was helping traffic circulate while admitting that it could be deadly for roadside plants and some trees.

Richard Stokoe, spokesman for the U.K. Local Government Association, told Bloomberg that more salt had been used on snow and ice for four days in early February than in all of 2008.

Stefan’s researchers recommended more judicious use of salt by road crews and Minnesota snow plow drivers.

To contact the reporter of this story: Randall Hackley in Zurich at rhackley@bloomberg.net

Last Updated: February 11, 2009 08:50 EST