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2005年NPR美国国家公共电台三月-Studies Find High Mercury Levels in the W

时间:2007-07-17 01:46来源:互联网 提供网友:atm009e   字体: [ ]
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Studies that will be released today show that fish, birds and mammals in New England have significant amounts of mercury in their bodies. The studies find the toxic1 metal in some unexpected habitats and they suggest that power plants in the Midwest are a major source of mercury for the Northeast. NPR's Richard Harris reports.

Mercury pollution in the northeast should be getting better. In the past decade, mercury emissions2 from regional sources such as waste incinerators have been cut in half, but David Evers from the BioDiversity Research Institute in Gorham Maine says mercury levels in the environment remain stubbornly high.

-There is enough mercury fallen on the landscape anywhere in the northeast to cause problems. It's just the right recipe needs to be there to create a problem.

The new federally funded studies in the journal Ecotoxicology point out 9 hot spots where mercury contamination is a big problem. They range from southern Noverscoshed to northeast Massachusetts. In most of these places, the contamination isn't a surprise. Some of these areas are downwind of urban areas; others have environmental conditions such as acidic waters that promote mercury poisoning. But Evers also went to areas that are traditionally not thought of as trouble spots like dry mountaintops. He decided3 to look at big-nose thrush, an uncommon4 songbird that lives at high elevations5.

-There's a lot of people that ask me why you're doing this. There should be no mercury up there and my thought was why not, why not go to some of these habitats for these species that have high conservation concern and have a checklist to be able to say we don't have to worry about mercury in the species.

But Evers now reports some unsettling news about these forest dwelling6 birds.

-The big-nose thrush does have mercury levels in its body ,much higher than we would have predicted and so what we're finding is that mercury, in these mountaintops without staining water, is getting into these thrushes.

These birds don't eat fish, which is the usual route of exposure for birds.Eric Miller7 from a private firm called the Ecosystem's Research Group in Norvichful Mount thinks he's tracked down the source. Mountaintop mercury apparently8 comes from dry particles of mercury in the air ,those settle on mountain vegetation.

-We looked at mercury in leaves when they first emerge in the spring, say, deciduous9 leaves that are opening and emerging in the spring, and they have very low levels of mercury, and then a few weeks later, their level of mercury has increased and this continues throughout the growing season until a high level of mercury is present in these leaves at the end of the season.

Insects eat the leaves and the big-nose thrushes eat the insects. Biologists are now trying to figure out whether these mercury levels are high enough to affect the health of these species. One thing is for sure, Miller says, the government computer models that are supposed to predict how mercury travels through the air, don't predict that dry particles of mercury would be a problem. And those mercury particles come from distant sources, often coal-burning power plants. Some of it blows halfway10 around the globe from China, but a lot comes from power plants in the Midwest.

Miller documented these by studying mercury in rainfall. For example, at a monitoring station in Vermont,he found that 36 of the 38 most mercury-laden rainstorms started out as polluted clouds of air from elsewhere.

-And the air moved first over the Midwest or first over the eastern urban corridor prior to arriving in Vermont and depositing the mercury with a rainfall there.

The source of mercury is a huge political issue right now. Congress is planning to debate changes to the Clean Air Act which could well determine how quickly power plants scale back their mercury emissions. And the environmental protection agency is under a court order to announce a new mercury plan next week.
Richard Harris, NPR News.

点击收听单词发音收听单词发音  

1 toxic inSwc     
adj.有毒的,因中毒引起的
参考例句:
  • The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
  • There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。
2 emissions 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
3 decided lvqzZd     
adj.决定了的,坚决的;明显的,明确的
参考例句:
  • This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
  • There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。
4 uncommon AlPwO     
adj.罕见的,非凡的,不平常的
参考例句:
  • Such attitudes were not at all uncommon thirty years ago.这些看法在30年前很常见。
  • Phil has uncommon intelligence.菲尔智力超群。
5 elevations cb4bbe1b6e824c996fd92d711884a9f2     
(水平或数量)提高( elevation的名词复数 ); 高地; 海拔; 提升
参考例句:
  • Weight of the crust changes as elevations are eroded and materials are deposited elsewhere. 当高地受到侵蚀,物质沉积到别的地方时,地壳的重量就改变。
  • All deck elevations are on the top of structural beams. 所有甲板标高线均指结构梁顶线。
6 dwelling auzzQk     
n.住宅,住所,寓所
参考例句:
  • Those two men are dwelling with us.那两个人跟我们住在一起。
  • He occupies a three-story dwelling place on the Park Street.他在派克街上有一幢3层楼的寓所。
7 miller ZD6xf     
n.磨坊主
参考例句:
  • Every miller draws water to his own mill.磨坊主都往自己磨里注水。
  • The skilful miller killed millions of lions with his ski.技术娴熟的磨坊主用雪橇杀死了上百万头狮子。
8 apparently tMmyQ     
adv.显然地;表面上,似乎
参考例句:
  • An apparently blind alley leads suddenly into an open space.山穷水尽,豁然开朗。
  • He was apparently much surprised at the news.他对那个消息显然感到十分惊异。
9 deciduous 992yy     
adj.非永久的;短暂的;脱落的;落叶的
参考例句:
  • Overgrown deciduous shrubs can be cut back at this time of year.过于繁茂的落叶灌木可以在每年的这个时候修剪。
  • Deciduous trees shed their leaves in autumn.落叶树木在秋天落叶。
10 halfway Xrvzdq     
adj.中途的,不彻底的,部分的;adv.半路地,在中途,在半途
参考例句:
  • We had got only halfway when it began to get dark.走到半路,天就黑了。
  • In study the worst danger is give up halfway.在学习上,最忌讳的是有始无终。
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TAG标签:   npr  公共电台  study  mercury  level
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