Overview New Hampshire winters demand an effective and affordable means of de-icing roadways. The primary agent used for this purpose is sodium chloride (road salt), which is composed of 40 percent sodium ions (Na+) and 60 percent chloride ions (Cl-). Other components in salt like ferrocyanide, which is used for anti-caking, and impurities like phosphorus and iron, can represent up to 5 percent of the total weight. The sodium, chloride, ferrocyanide and impurities make their way into our environment through the runoff from rain, melting snow and ice, as well as through splash and spray by vehicles and by wind. They find their way onto vegetation and into the soil, groundwater, stormdrains, and surface waters causing significant impact to the environment. Chloride (Cl-) is completely soluble and very mobile. Chloride is toxic to aquatic life and impacts vegetation and wildlife. There is no natural process by which chlorides are broken down, metabolized, taken up, or removed from the environment. In 2008, New Hampshire listed 19 water bodies impaired by chloride; in 2010 that number increased to 40. Trends show that chloride levels continue to rise with increasing use of road salt. The transport of sodium (Na+) in the environment is not as prominent as chloride due to ion exchange; however, this exchange can alter the soil chemistry by replacing and releasing nutrients into the groundwater and surface water changing soil structure and impacting the aquatic environment. Contamination of sodium in drinking water is a concern for individuals restricted to low-sodium diets due to hypertension (high blood pressure). Wildlife is also prone to high sodium levels by ingesting salt or drinking water runoff from snow and ice melt. Additives to road salt like ferrocyanide, which is used as an anti-caking compound in large salt supplies, can have impacts on both the environment and human health due to cyanide ions being released by certain types of bacteria as well as from exposure to sunlight. The USEPA in 2003 added this compound to its list of toxic pollutants under section 307(a) of the Clean Water Act. Other potential components and impurities of road salt can include calcium, potassium, iron, magnesium, aluminum, lead, phosphorus, manganese, copper, zinc, nickel, chromium, and cadmium.