球状肥料对土壤污染相对较小
文章来源:未知 文章作者:meng 发布时间:2010-11-18 03:31 字体: [ ]  进入论坛
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There is considerable amount of uncertainty1 concerning the environmental impacts that animal hormones2 have on surface water. Higher concentrations of hormones in waterways have been found to cause physiological3 and sexual impairment(损伤) in fish and other aquatic4(水生的) species. However, a study from the University of Delaware that examined estrogen(雌性激素) concentrations runoff from agricultural fields fertilized5 with chicken manure6(鸡粪) found that it is as much about the application of the manure as it is about the measurement of the types of estrogen. The study was conducted on the experimental plots on the Coastal7 Plain agricultural soils in Middletown, DE. It measured and compared the amounts of both toxic8, free forms of estrogen hormones and less toxic species found in runoff. Corn was planted as a cover crop and chicken manure was applied9 in either a pelletized(球状的) form or a raw litter form. Reduced tillage(耕作,耕种) and no tillage treatments were also employed. Samples of surface runoff were collected after 10 rain storms during the 2008 summer growing season from April through July.

Sudarshan Dutta, the author of the study, found that the amounts of estrogen were lower in plots fertilized with pelletized manure and plots that received no-tillage treatments.

Additionally, Dutta discovered the entire range of estrogen concentrations in the samples was significantly lower than those observed in other previous agricultural studies. Nevertheless, concentrations of the less toxic conjugate10(结合的) forms of estrogen were higher than the toxic, free forms.

According to Dutta, prior studies did not usually measure the conjugate forms of estrogen, saying it is necessary to measure these forms.

"The higher concentration of conjugate forms of estrogens underscores the need for reporting all forms of the hormones. This is especially critical considering that conjugate species can be converted to the toxic free forms under certain environmental conditions," he says.



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1 uncertainty NlFwK     
n.易变,靠不住,不确知,不确定的事物
参考例句:
  • Her comments will add to the uncertainty of the situation.她的批评将会使局势更加不稳定。
  • After six weeks of uncertainty,the strain was beginning to take its toll.6个星期的忐忑不安后,压力开始产生影响了。
2 hormones hormones     
n. 荷尔蒙,激素 名词hormone的复数形式
参考例句:
  • This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
  • The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。
3 physiological aAvyK     
adj.生理学的,生理学上的
参考例句:
  • He bought a physiological book.他买了一本生理学方面的书。
  • Every individual has a physiological requirement for each nutrient.每个人对每种营养成分都有一种生理上的需要。
4 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。
5 Fertilized 0f66e269f3e72fa001554304e59712da     
v.施肥( fertilize的过去式和过去分词 )
参考例句:
  • The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。
  • Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。
6 manure R7Yzr     
n.粪,肥,肥粒;vt.施肥
参考例句:
  • The farmers were distributing manure over the field.农民们正在田间施肥。
  • The farmers used manure to keep up the fertility of their land.农夫们用粪保持其土质的肥沃。
7 coastal WWiyh     
adj.海岸的,沿海的,沿岸的
参考例句:
  • The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
  • This country will fortify the coastal areas.该国将加强沿海地区的防御。
8 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。
9 applied Tz2zXA     
adj.应用的;v.应用,适用
参考例句:
  • She plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
10 conjugate PY1yA     
vt.使成对,使结合;adj.共轭的,成对的
参考例句:
  • A partition that is its own conjugate is ealled self-conjugate.一个分析如与其自身共轭称为自共轭。
  • It is important to learn to conjugate irregular verbs.学会不规则动词的变化是相当重要的。
TAG标签: water species toxic hormones
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