送交者: Latino2 于 2005-9-07, 10:40:17:
研究结果表明，撒在路上用来防止路面结冰的盐会渗入河里，使水质逐渐盐化，如果继续使用这一方法，.到下个世纪,美国东北部的河水及湖水将不再适合饮用及生物生存.
法姑他们鞑地的冬天使用什么方法防止路面结冰？
结冰的路上还能跑田牛？
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Salt on the Asphalt
Salt used to deice roads is trickling into small streams and gradually making them more saline, according to a new study. Within the next century, the salt could turn rivers and lakes in the northeastern U.S. toxic, rendering the water unfit for drinking and making it uninhabitable for freshwater fish and plant life, say researchers.
The use of salt to rid roads of ice is common practice during winter. When the ice melts, the salty water flows into gutters meant to drain rainwater. That means the salt slowly finds its way to tiny streams, say scientists. Much of the increased salinity observed in such small rivulets comes from chloride, a constituent of salt. However, little is known about how much this boosts the salinity of rivers and lakes.
To find out, Sujay Kaushal, an ecologist at the University of Maryland, Baltimore, and his team looked at chloride concentrations in streams and rivers in Maryland's Baltimore County, the Hudson River Valley in New York, and the White Mountains of New Hampshire. Typically, chloride concentrations of about 250 milligram per liter can make the water harmful to plants and humans. But the samples analyzed by Kaushal's team suggest that during winter, some streams have a chloride content almost 20 times higher--nearly 5000 milligrams per liter. That's about a quarter of the chloride content found in seawater. Besides making water undrinkable, increased salinity could impair bacterial processes that help cleanse the water and leave freshwater ecosystems vulnerable to invasion by organisms suited to salt water, says Kaushal, whose team reports its findings online this week in Proceedings of the National Academy of Sciences.
This paper demonstrates "a very important but overlooked consequence of road-building on our water resources," says Judith Meyer, an ecologist at the University of Georgia, Athens. To address the issue, William Lewis Jr., a limnologist at the University of Colorado, Boulder, suggests using expensive corn-based deicers, or a more controlled application of road salt.
Science News