时间:2018-12-17 作者:英语课 分类:2009年NPR美国国家公共电台7月


英语课
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 toxic 1 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 emissions 2 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 decided 3 to look at big-nose thrush, an uncommon 4 songbird that lives at high elevations 5.

-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 dwelling 6 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 Miller 7 from a private firm called the Ecosystem's Research Group in Norvichful Mount thinks he's tracked down the source. Mountaintop mercury apparently 8 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, deciduous 9 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 halfway 10 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.


1 toxic
adj.有毒的,因中毒引起的
  • 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
排放物( emission的名词复数 ); 散发物(尤指气体)
  • 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
adj.决定了的,坚决的;明显的,明确的
  • 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
adj.罕见的,非凡的,不平常的
  • 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
(水平或数量)提高( elevation的名词复数 ); 高地; 海拔; 提升
  • 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
n.住宅,住所,寓所
  • 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
n.磨坊主
  • 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
adv.显然地;表面上,似乎
  • 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
adj.非永久的;短暂的;脱落的;落叶的
  • 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
adj.中途的,不彻底的,部分的;adv.半路地,在中途,在半途
  • 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。
学英语单词
acid annealing
aleurone cells of endosperm
anoxic pore water
antenna long-wire
Arleux
augmental off-gas system
authorized data list
brought to the table
buffer plate
buried drain
calonectris leucomelas
canister-shot
capacity resistence time constant
chronosequence
coal cassification
coherent processing system parameter
coloured vase
composite depreciation method
constaff
constant current potentiometry
convenien
coroner's court
crushing force
deposition of radioactive dust
dinicotinoylornithine
EFR
Environmental Study Conference
fan-brake
free-thinning
gamma ray dosimeter
H. & S.
haloform
hanged around
haptically
Hartley, Marsden
headiness
hearthwares
hinchcliff
hogling
immunity resistant
insect bar
interspousal
ipsm
Julian Alps
Kven
lead totanate ceramics
Macewen's operation
mental arithmetic
misspender
muldaur
multienzyme complex
narchinol
national defence economics
national-savings
neighborhood parks
neosurrealists
newton's friction law
North Plains
obad
operation elements
optimal rate of mark up
Oterben
output of systems analysis and design
Pediapred
peer acceptance
pestalotia aucubae hara
potassium carbonate peroxyhydrate
preoptive control
product-mixes
promurit
puristical
pyridoxine hydrochloride
residual-ore deposit
resoundable
revives
room mining
San Salvador
Savona
Sechuana
sederunt
shed the blood of someone
single sweep
soil stratigraphy
soil test
SSI (secondary side inspection)
substrate orientation
sweettalks
take breath away
thyroidism
ticker-tape
toogh
town-hall
trachelomonas pseudobulla
trouble-free
two-byte conversion
vacuum bypass
valley shape factor
vertical slit arc-chute
wagon wheel grain
water-tight regulations
woolner
Yucatan Current