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New Hampshire Department of Environmental Services


Dramatic and rising concentrations of chloride from road salt have been identified in New Hampshire waters and mirror a trend that is being seen in colder regions of the US and Canada due to the application of de-icing chemicals. In 2008 New Hampshire listed 19 chloride-impaired water bodies on the 303(d) list under the Clean Water Act. In 2012 that number increased to 46. At concentrations exceeding 230 mg/l chloride can be toxic to some aquatic species, and can impart a salty taste in drinking water supplies. 

At this time, the only way to prevent chloride from reaching surface and ground water is to reduce the amount applied to our roadways and parking lots without compromising safety. When road salt dissolves in water, the chloride molecule is not retained by the soil and easily moves with water flow. Chloride is not significantly removed by chemical reactions, evaporation, or vegetation. Therefore, nearly all of the chloride applied to the land surface as road salt will eventually end up in the nearby surface waters or groundwater.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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