首页
登录
职称英语
Polluted water is nothing new in the United States. We have lived through fl
Polluted water is nothing new in the United States. We have lived through fl
游客
2023-07-11
14
管理
问题
Polluted water is nothing new in the United States. We have lived through flaming rivers and caustic creaks that could take the hide off a hound. For decades, however, efforts to safeguard drinking water were hampered because no one had an accurate sense of the full range of contaminants in the water supply, nor of the geographic extent of the pollution. This year two separate research teams unveiled sophisticated new tools to find out exactly what chemical dangers are lurking in freshwater streams.
"Research in Europe in the 1990s showed that pharmaceuticals were turning up in the water," says Dana Kolpin, leader of a U. S. Geological Survey Water Resources Division research ream that developed five new analytic methods for measuring water contaminants." Our big effort was to develop methods to measure very small amounts of organic chemicals. ’ The research team fanned out across 30 states nationwide and conducted two years of sampling from 139 streams. They were chosen, says Kolpin, on the basis of their location downstream from" intense urbanization and livestock production." In a study published in the March 15 Journal of Environmental Science & Technology, Kolpin and his colleagues reported they looked for 95 different contaminants, such as antibiotics, steroids, hormones, antioxidants, plasticizers, and various solvents. They found 82 of them. Nearly 80 percent of the streams showed one or more of the contaminants. The median stream contained seven. Even the good news--that the most frequently detected contaminants like fecal steroids, cholesterol, insect repellent, caffeine, disinfectant, fire retardant, and detergents were found in generally low concentrations--had to be qualified. Many of those compounds have no guidelines for safe amounts, and little is known about the effects of chronic exposure or the interactive effects of compounds that have been detected together.
In a related Environmental Protection Agency study that is still in progress, a team of scientists at the Johns Hopkins Whiting School of Engineering is using gas chromatography and mass spectrometry to detect the presence of various anticonvulsants and anticancer drugs in drinking water. Led by Lynn Roberts and Ed Bouwer, the researchers track samples at sewage-treatment facilities in Massachusetts and Maryland to determine whether and in what quantities pharmaceuticals are getting through the waste-treatment plants and the extent to which they may be accumulating in coastal waters.
The goal of both research teams is to provide a baseline of what organic compounds are in the water, in what quantities, and how they are getting there--key steps toward ensuring that the water we drink isn’t killing us. [br] Which of the following statements is true?
选项
A、Altogether 95 different contaminants have been found in streams.
B、Nearly 80 percent of the streams surveyed contains only the familiar contaminants.
C、The most frequently detected contaminants are usually in low concentrations.
D、The average number of contaminants in each stream surveyed is seven.
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2827787.html
相关试题推荐
Lastyear’seconomyintheUnitedStatesshouldhavewontheOscarforbest
Lastyear’seconomyintheUnitedStatesshouldhavewontheOscarforbest
Lastyear’seconomyintheUnitedStatesshouldhavewontheOscarforbest
Lastyear’seconomyintheUnitedStatesshouldhavewontheOscarforbest
Lastyear’seconomyintheUnitedStatesshouldhavewontheOscarforbest
WhendidwatchesandclocksbecomecommonintheUnitedStates?[br][originalt
WhendidwatchesandclocksbecomecommonintheUnitedStates?[br][originalt
[originaltext]MyfirstsemesterofcollegewastheworstI’vebeenthrough.
[originaltext]MyfirstsemesterofcollegewastheworstI’vebeenthrough.
It____________(是很容易证明的)thatnothingismorepreciousthantime.canbeeasilyb
随机试题
Asmenage,theytypicallygetlessandlessdeepsleep—afactthatcould【B
紫癜性肾炎肾免疫病理特点为A.无免疫球蛋白和补体成分沉积 B.以IgG和C为主
30岁孕妇,孕35周,胎心168次/分,首先采取的护理措施是( )A.左侧卧位
A.智力及动作发育落后有倒退现象 B.兴奋、多动 C.注意力不集中,记忆力减
根据《关于进一步加强保荐机构内部控制有关问题的通知》,保荐机构应当对保荐项目的重
建设工程质量监督档案按单位工程建立,要求(),经监督机构负责人签字后归档。A
慢性呼吸衰竭病程中,最常见的酸碱平衡失调是A.呼吸性碱中毒 B.呼吸性酸中毒
弹好营商环境的二重奏 任燕没想到创业就会变得如此简单和便捷,这一切都得益于
执行理财规划方案时的原则包括( )。A.了解原则 B.连续性原则 C.明确
下列钢材性能中,属于工艺性能的有()。A.拉伸性能 B.冲击性能 C.疲劳
最新回复
(
0
)