Thursday, September 29, 2005
Science highlights Kaushal's study on road salt, published in
Proc. Natl. Acad. Sci. U.S.A. 102, 13517 (2005):
"Fresh water is one of the most important resources and is vital for humans, agriculture, and natural ecosystems. There are many threats to the supply of this commodity, including climate change; pollution by industrial, agricultural, and automotive wastes; and overuse. Kaushal et al.add another: road salt. Road salt is used liberally in areas of the northeastern United States that receive appreciable amounts of snow, and the runoff into urban and suburban watersheds is a growing threat to fresh water reserves. By measuring the concentration of chloride in streams in Maryland, New York, and New Hampshire during winters, the authors show that salinities are approaching 25% that of seawater in some cases and are greater than 100 times that ofpristine forest streams during summers. Watersheds where roads are densest are under severe pressure. If salinity in these regions continues to increase, surface water supplies in the Northeast may become unfit for human consumption and toxic to freshwater organisms by the end of the century."