煤灰对生态环境的影响
文章来源:未知 文章作者:meng 发布时间:2010-11-30 02:13 字体: [ ]  进入论坛
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As the U.S. Environmental Protection Agency weighs whether to define coal ash as hazardous1 waste(有害垃圾) , a Duke University study identifies new monitoring protocols2 and insights that can help investigators3 more accurately4 measure and predict the ecological5 impacts of coal ash contaminants(污染物) . "The take-away lesson is we need to change how and where we look for coal ash contaminants," says Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment. "Risks to water quality and aquatic6 life(水生生物) don't end with surface water contamination, but much of our current monitoring does."

The study, published online this week in the peer-reviewed journal Environmental Science and Technology, documents contaminant levels in aquatic ecosystems7 over an 18-month period following a massive coal sludge(烂泥,泥泞) spill in 2008 at a Tennessee Valley Authority power plant in Kingston, Tenn.

By analyzing8 more than 220 water samples collected over the 18-month period, the Duke team found that high concentrations of arsenic9 from the TVA coal ash remained in pore water -- water trapped within river-bottom sediment10 -- long after contaminant levels in surface waters dropped back below safe thresholds(门槛) . Samples extracted from 10 centimeters to half a meter below the surface of sediment in downstream rivers contained arsenic levels of up to 2,000 parts per billion – well above the EPA's thresholds of 10 parts per billion for safe drinking water, and 150 parts per billion for protection of aquatic life.

"It's like cleaning your house," Vengosh says of the finding. "Everything may look clean, but if you look under the rugs, that's where you find the dirt."

The potential impacts of pore water contamination extend far beyond the river bottom, he explains, because "this is where the biological food chain begins, so any bioaccumulation(生物体内积累) of toxins11 will start here."

The research team, which included two graduate students from Duke's Nicholas School of the Environment and Pratt School of Engineering, also found that acidity12 and the loss or gain of oxygen in water play key roles in controlling how arsenic, selenium and other coal ash contaminants leach13 into the environment. Knowing this will help scientists better predict the fate and migration14 of contaminants derived15 from coal ash residues16, particularly those stored in holding ponds and landfills, as well as any potential leakage17 into lakes, rivers and other aquatic systems.

The study comes as the EPA is considering whether to define ash from coal-burning power plants as hazardous waste. The deadline for public comment to the EPA was Nov. 19; a final ruling -- what Vengosh calls "a defining moment" -- is expected in coming months.

"At more than 3.7 million cubic meters, the scope of the TVA spill is unprecedented18, but similar processes are taking place in holding ponds, landfills and other coal ash storage facilities across the nation," he says. "As long as coal ash isn't regulated as hazardous waste, there is no way to prevent discharges of contaminants from these facilities and protect the environment."



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1 hazardous Iddxz     
adj.(有)危险的,冒险的;碰运气的
参考例句:
  • These conditions are very hazardous for shipping.这些情况对航海非常不利。
  • Everybody said that it was a hazardous investment.大家都说那是一次危险的投资。
2 protocols 66203c461b36a2af573149f0aa6164ff     
n.礼仪( protocol的名词复数 );(外交条约的)草案;(数据传递的)协议;科学实验报告(或计划)
参考例句:
  • There are also protocols on the testing of nuclear weapons. 也有关于核武器试验的协议。 来自辞典例句
  • Hardware components and software design of network transport protocols are separately introduced. 介绍系统硬件组成及网络传输协议的软件设计。 来自互联网
3 investigators e970f9140785518a87fc81641b7c89f7     
n.调查者,审查者( investigator的名词复数 )
参考例句:
  • This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
  • The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》
4 accurately oJHyf     
adv.准确地,精确地
参考例句:
  • It is hard to hit the ball accurately.准确地击中球很难。
  • Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。
5 ecological IrRxX     
adj.生态的,生态学的
参考例句:
  • The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
  • Each animal has its ecological niche.每种动物都有自己的生态位.
6 aquatic mvXzk     
adj.水生的,水栖的
参考例句:
  • Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
  • We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。
7 ecosystems 94cb0e40a815bea1157ac8aab9a5380d     
n.生态系统( ecosystem的名词复数 )
参考例句:
  • There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
  • Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样,从雨林到半荒漠等不一而足。 来自辞典例句
8 analyzing be408cc8d92ec310bb6260bc127c162b     
v.分析;分析( analyze的现在分词 );分解;解释;对…进行心理分析n.分析
参考例句:
  • Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据,暴露出的问题甚至更大。 来自辞典例句
  • He undoubtedly was not far off the mark in analyzing its predictions. 当然,他对其预测所作的分析倒也八九不离十。 来自辞典例句
9 arsenic 2vSz4     
n.砒霜,砷;adj.砷的
参考例句:
  • His wife poisoned him with arsenic.他的妻子用砒霜把他毒死了。
  • Arsenic is a poison.砒霜是毒药。
10 sediment IsByK     
n.沉淀,沉渣,沉积(物)
参考例句:
  • The sediment settled and the water was clear.杂质沉淀后,水变清了。
  • Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。
11 toxins 18c3f40d432ba8dc33bad8fb82873ea8     
n.毒素( toxin的名词复数 )
参考例句:
  • The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
  • Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》
12 acidity rJyya     
n.酸度,酸性
参考例句:
  • This plant prefers alkaline soil,though it will readily tolerate some acidity.这种植物在酸性土壤中也能生存,但硷性土壤更加适宜。
  • Gastric acidity would not prevent the organism from passing into the gut.胃的酸度不能防止细菌进入肠道。
13 leach uxCyN     
v.分离,过滤掉;n.过滤;过滤器
参考例句:
  • Liquid water can leach soluble materials from the interface.液态水能够从界面溶解出可溶性物质。
  • They believe that the humic materials are leached from decaying plant materials.他们认为腐植物料是从腐烂的植物体浸沥而来。
14 migration mDpxj     
n.迁移,移居,(鸟类等的)迁徙
参考例句:
  • Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
  • He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。
15 derived 6cddb7353e699051a384686b6b3ff1e2     
vi.起源;由来;衍生;导出v.得到( derive的过去式和过去分词 );(从…中)得到获得;源于;(从…中)提取
参考例句:
  • Many English words are derived from Latin and Greek. 英语很多词源出于拉丁文和希腊文。 来自《简明英汉词典》
  • He derived his enthusiasm for literature from his father. 他对文学的爱好是受他父亲的影响。 来自《简明英汉词典》
16 residues 3e5a3e323766c2626c2be0d6feafa1da     
n.剩余,余渣( residue的名词复数 );剩余财产;剩数
参考例句:
  • pesticide residues in fruit and vegetables 残留在水果和蔬菜中的杀虫剂
  • All organic and metallic residues on the wafers must be removed. 片子上所有的有机和金属残留物均必须清除。 来自辞典例句
17 leakage H1dxq     
n.漏,泄漏;泄漏物;漏出量
参考例句:
  • Large areas of land have been contaminated by the leakage from the nuclear reactor.大片地区都被核反应堆的泄漏物污染了。
  • The continuing leakage is the result of the long crack in the pipe.这根管子上的那一条裂缝致使渗漏不断。
18 unprecedented 7gSyJ     
adj.无前例的,新奇的
参考例句:
  • The air crash caused an unprecedented number of deaths.这次空难的死亡人数是空前的。
  • A flood of this sort is really unprecedented.这样大的洪水真是十年九不遇。
TAG标签: coal ecological ash
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