首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Lead deposits, which accumulated in soil and snow during the 1960’s and 1970’s, were primarily the result of leaded gasoline emi
Lead deposits, which accumulated in soil and snow during the 1960’s and 1970’s, were primarily the result of leaded gasoline emi
admin
2010-01-13
107
问题
Lead deposits, which accumulated in soil and snow during the 1960’s and 1970’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation world-wide has decreased significantly.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.
In a study published in the journal Ambio, scientists found that lead levels in soil in the North-eastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统)respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
The study published in the journal Nature indicates that______.
选项
A、lead deposits in arctic snow are on the increase
B、the Clean Air Act has not produced the desired results
C、the US is the major source of lead pollution in arctic snow
D、lead will stay in soil and snow longer than expected
答案
C
解析
细节理解题。由第二段第一句可知,“美国排放的含铅气体是格陵兰雪地中高含铅量的主要贡献者”。故选C项。
转载请注明原文地址:https://kaotiyun.com/show/pMmi777K
0
在职申硕(同等学力)英语
相关试题推荐
Thecentury-oldhostilitiesbetweenthetwotribeseventuallyterminatedthroughthepersistenteffortsofthelocalgovernment.
Andreaallowedthehitchhikertotakearideinhercar,mainlybecause______Andreasuddenlystoppedthecarbecause______
AleadingBritishscholarhasproposedtranslatingShakespeareintocontemporaryEnglish______youngaudienceswhoareconfused
Whatpartdoesthefemaleseahorseplayinhavingbabies?Whichfactdoestheauthorwantthereadertoremembermost?
Childrenmodelthemselveslargelyontheirparents.Theydosomainlythroughidentification.Childrenidentify【C1】______apar
______allofuswhoareheretonight,IwouldliketothankMr.Johnsonforhisinformativetalk.
Ourreadersarecomfortablewithourclear,______wordsthatinformandentertainthem.
Formanypeopletoday,readingisnolongerrelaxation.Tokeepuptheirworktheymustreadletters,reports,tradepublication
Formanypeopletoday,readingisnolongerrelaxation.Tokeepuptheirworktheymustreadletters,reports,tradepublication
AllthestaffmembersofthedepartmentmadezealouseffortstocleanupthehallfortheChristmasparty.
随机试题
企业成长的基础是()
A.出生后2~3天到2个月内B.2个月C.8个月以上D.3个月E.1个月卡介苗的初种年龄是
若发包人在收到监理机构的同意索赔申请决定14天后未予答复,应视为()。
请根据所提供的单据,完成以下相关的判断题。
单位或个体工商户聘用的员工为本单位或者雇主提供加工、修配劳务,不征收增值税。()
汽车:汽油
【2015-2】杜威在《我的教育信条》中说“我相信唯一的真正教育是通过对儿童能力的刺激而来的,这种刺激是儿童自己感觉到的社会情景的各种要求所引起的。”这种对教育的定义属于()。
Somedoctorsaretakinganunusualnewapproachtocommunicatebetterwithpatients—theyareletting【C1】_________readthenotes
What’sTom’stelephonenumber?
Thepolicelethimgo,becausetheydidn’tfindhimguilty_______themurder.
最新回复
(
0
)