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xx年职称英语综合类A级概括大意模拟试题xx年职称英语综合类A级概括大意模拟试题 The importanceof particularmetals in the human diet has been realizedwithin thepast fewdecades,and theidea thatgeology mightbe relatedto healthhasbeenrecognized fora numberof elementssuch asiodine,zinc andselenium.For example,soils withlow iodinecontents producecrops,and animalsdeficient iniodine.A lackof iodineinthe humandietleads tosome seriousdiseases. The ultimatesource ofmetals withinthehumanbody isrocks,which weatherinto soil,gaining orlosing someof theirchemical constituents.The cropswe eatselectively rem ove fromthe soilthe elementsthat theyrequire forgrowth.The waterwe drinkcontains traceelements leachedfrom rockand soil.Thus thegeology andgeochemistry ofthe environmentshave effectson thechemistry andhealth ofplants,animals andpeople. So farthere isno datato suggestthat peopleliving onmetal-rich soilsexperience apotential healthhazard.The levelso...。