学位英语

Geology and Health

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 ……

Key: DABCECBF

相关推荐：2017年职称英语报名时间及入口

报考条件：综合类，理工类，卫生类考试原则上没有严格的界限。职称英语考试报名可在单位报，评职称与户口无关，主要看你的工作单位，所以你可以直接咨询单位的人事部门，如果他们说可以就行，每个省规定不大一样。【查看详情】

报考选择：职称英语报考科目|级别选择|报名条件及相关问题解答

免考规定：取得外语(从事翻译工作人员及外语教师第二外语)专业专科及以上学历的人员申报中、高级职称评审……。【查看详情】

（责任编辑：hbz）

共2页,当前第1页  第一页  前一页  下一页