最新2018职称英语考试时间_2017职称英语卫生类：英语概括大意专项练习题(18).doc

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1、最新2018职称英语考试时间_2017职称英语卫生类：英语概括大意专项练习题(18)职称英语网权威发布2017职称英语卫生类：英语概括大意专项练习题(18)，更多2017职称英语卫生类相关信息请访问职称英语考试网。Geology and HealthThe 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 f

2、or 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 so

3、il, 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 che

4、mistry 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-ric

5、h 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.Heav

6、y 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 als

7、o 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.T

8、here 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

9、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 soilB. Potential hazards of human contaminated soilsC. Research on chan

10、nels of heavy metals getting into human food chainD. Geology and health problemsE. Rocks-the ultimate source of soil pollutionF. Long- term health effects on children1. Paragraph 12. Paragraph 33. Paragraph 44. Paragraph 6A. industrially polluted soilsB. rock and soil chemistryC. naturally polluted

11、soilsD. the pathways of metals into the food chainE. the element of iodineF. the persistence of heavy metals5. 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 on8. Industrially contaminated sites usually require a thorough clean-up due to Key: DABCECBF第 4 页 共 4 页