英语阅读练习
概括大意与完成句子
The importance of particular metals in the human diet has been realized within the past few decades, and the idea that geology might be related to health has been recognized for a number of elements such as iodine, zinc and selenium. For example, soils with low iodine contents produce crops, and animals deficient in iodine. A lack of iodine in the human diet leads to some serious diseases.
The ultimate source of metals within the human body is rocks, which weather into soil, gaining or losing some of their chemical constituents. The crops we eat selectively remove from the soil the elements that they require for growth. The water we drink contains trace elements leached from rock and soil. Thus the geology and geochemistry of the environments have effects on the chemistry and health of plants, animals and people.
So far there is no data to suggest that people living on metal-rich soils experience a potential health hazard. The levels of metals within naturally contaminated soils are generally not high enough to cause serious health problems. Living on metal-rich soils does not represent a health risk unless large quantities of soil are digested or metal-rich dust is inhaled. However, small children are particularly exposed to metal-rich topsoil in playgrounds and gardens. They are also the most likely ones to eat potentially dangerous metal-rich soil.
Heavy metals are persistent; they do not break down to other chemicals in the environment. Industrially polluted sites usually undergo intensive clean-up and rehabilitation because heavy metals are a health concern once they enter the food chain. Some trace metals are alleged to cause cancer and are also known to cause poisoning.
In contrast, naturally contaminated soils have not been subject to risk assessment studies and rehabilitation measures, despite the fact that they frequently possess metal concentrations well above those of such polluted by humans and above environmental quality criteria.
There is a vital need to understand the potential risks and long-term health effects of living on naturally contaminated soils. Future environmental investigations of naturally polluted soils should concentrate on the potential pathways of metals into the food chain and human body. Geologists should be part of such studies as they can provide the essential background information on rock and soil chemistry as well as the chemical forms of heavy metal pollution.
A. No evidence to indicate bad effects of naturally contaminated soil
B. Potential hazards of human contaminated soils
C. Research on channels of heavy metals getting into human food chain
D. Geology and health problems
E. Rocks-the ultimate source of soil pollution
F. Long- term health effects on children
1. Paragraph 1
2. Paragraph 3
3. Paragraph 4
4. Paragraph 6
A. industrially polluted soils
B. rock and soil chemistry
C. naturally polluted soils
D. the pathways of metals into the food chain
E. the element of iodine
F. the persistence of heavy metals
5. Some serious diseases is connected with deficiency of ……
6. It is extremely necessary to study the long-term effects caused by living on ……
7. Geologists are indispensable in the research project on geology and health due to their knowledge on……
8. Industrially contaminated sites usually require a thorough clean-up due to ……
参考答案: DABCECBF
-
采桑子原文及赏析15篇[集合]
采桑子原文及赏析1采桑子·辘轳金井梧桐李煜〔五代〕辘轳金井梧桐晚,几树惊秋。昼雨新愁,百尺虾须在玉钩。琼窗春断双蛾皱,回首边头。欲寄鳞游,九曲寒波不泝流。(泝流一作:溯流)译文:深秋时节,梧桐树下,辘轳金井旁,落叶满地。树木入秋而变,人见秋色而愁。手扶百尺垂帘,眼...
-
《谁动了我的奶酪》优秀读后感范文(通用31篇)
当阅读完一本名著后,大家对人生或者事物一定产生了许多感想,是时候静下心来好好写写读后感了。你想知道读后感怎么写吗?下面是小编为大家收集的《谁动了我的奶酪》优秀读后感范文,仅供参考,欢迎大家阅读。《谁动了我的奶酪》优秀读后感篇1我喜欢这本书,因为它是一个...
-
助学金申请书[精华]
在现在的社会生活中很多场合都离不了申请书,请注意不同的对象有不同的申请书。那么一般申请书是怎么写的呢?下面是小编整理的助学金申请书,欢迎阅读与收藏。助学金申请书1尊敬的校老师,领导:你们好!我来自家庭贫困的农村,父母都是农民,既没有文化,也没有本钱,又无一技之...
-
初二开学第一课观后感范文600字(通用30篇)
当认真看完一部影视作品后,相信大家有很多值得分享的东西吧,为此需要好好认真地写观后感。那么我们该怎么去写观后感呢?以下是小编为大家整理的初二开学第一课观后感范文600字,欢迎阅读与收藏。初二开学第一课观后感600字篇1今年的《开学第一课》以“奋斗成就梦想...