阅读下面这篇短文，短文后有2项测试任务：（1）第23～26题要求从所给的6个选项中为第1、3、4、6段每段选择l个正确的小标题；（2）第27～30题要求从所给的6个选项中选择4个正确选项，分别完成每个句子。请将答案涂在答题卡相应的位置上

Geology and Health

　　1．The importance of particular metals in the human diet has been realised 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．

　　2．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 environment have effects on the chemistry and health of plants,animals and people．

　　3．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 no thigh 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 dust topsoil in playgrounds and gardens．They are also the most likely ones to eat potentially dangerous metal-rich soil．

　　4．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．

　　5．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．

　　6．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．

　　23．Paragraph l ___________

　　24．Paragraph 3 ___________

　　25．Paragraph 4 ___________

　　26．Paragraph 6 ___________

　　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

　　27．Some serious diseases is connected with deficiency of _____________．

　　28．It is extremely necessary to study the long-term effects caused by living on ___________________．

　　29．Geologists are indispensable in the research project on geology and health due to their knowledge on ___________________．

　　30．Industrially contaminated sites usually require a thorough clean up due to ___________________．

　　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

　　参考答案：

　　23 D　第一段点出主题，即某些金属进入人类食谱可能与地质有关。

　　24 A　第三段涉及的是自然污染的土壤一般情况下对人体不会造成危害。此段首句就提示了这一点：So far there is no data to suggest that people living on metal—rich soils experience a potential health hazard．

　　25 B　第四段说，受到工业污染的土壤含有重金属，而重金属很稳定，不容易降解，因此，某些微量重金属被认为有可能与癌症有关，并引起中毒。

　　26 C　答案的依据是本段的第二句：Future environmental investigations of naturally polluted soils should concentrate on the potential pathways of metals into the food chain and human body．

　　27 E　第一段最后一句：A lack of iodine in the human diet leads to some serious diseases，是选择E的依据。

　　28 C　本题答案的依据是最后一段的第一句，即There is a vital need to understand the potential risks and lon9—term health effects of living on naturally contaminated soils．

　　29 B　全文都在论述重金属的摄入可能会对人体健康产生有害影响，最后一段说到地质学家在解决调查这个问题能起的作用。这个句子是：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．

　　30 F　第四段涉及这一问题。受到工业污染的土壤含有重金属，而重金属很稳定，不容易降解，所以，要对重金属进行彻底的清除。