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
外语
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emiss
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emiss
admin
2010-02-20
19
问题
Lead deposits, which accumulated in soil and snow during the 1960’s and 70’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 worldwide has decreased significantly.
A study published recently in the journal Nature shows that airborne 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 gasoline and thus enable scientists to differentiate (分区) 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 Northeastern 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 up per 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 authors of the Ambio study have found that ______.
选项
A、forests get rid of lead pollution faster than expected
B、lead accumulations in forests are more difficult to deal with
C、lead deposits are widely distributed in the forests of the US
D、the upper layers of soil in forests are easily polluted by lead emissions
答案
A
解析
细节判断题。本题符合第六段最后一句话。
转载请注明原文地址:https://kaotiyun.com/show/Hwt7777K
0
大学英语四级
相关试题推荐
ItisappropriateforChinesecollegestudentstolearnatleastoneforeignlanguagebeforetheygraduatesothattheycan____
AfterWorldWarIImostAustralianswerecautiousaboutprospectsforthefuture.OldtimeAustralianhomesusuallyhadnoslic
Thegrowthofpopulationduringthepastfewcenturiesisnoproofthatpopulationwillcontinuetogrowstraightupwardtoward
Accordingtothepassage,whatwasbadlyneededtoimproveindustrialefficiency?CharlesBabbage,anEnglishacademic,______.
A、TheancestorsofsomeoftheThaipeopleareChinese.B、SomeoftheThaipeoplehaveimmigratedfromChina.C、SomeoftheThai
HarlemRenaissancereferstoaperiodlastingformorethan10years,duringwhichagroupofAfricanandAmericanwritersprodu
HarlemRenaissancereferstoaperiodlastingformorethan10years,duringwhichagroupofAfricanandAmericanwritersprodu
HarlemRenaissancereferstoaperiodlastingformorethan10years,duringwhichagroupofAfricanandAmericanwritersprodu
A、He’llprobablyneverfinishwritingthatpaper.B、He’llfinishitthedayaftertomorrow.C、Heworksonlyduringtheday.D、He
随机试题
脂酸β-氧化、酮体生成及胆固醇合成的共同中间产物是
哪项结果不符合肝门部胆管癌
反映“医患关系为契约关系”的是( )。反映“医患关系是信托关系”的是( )。
血吸虫病的肠道改变主要累及的部位包括()。
某外商投资企业的业务收支以美元为主,该企业可以以美元作为记账本位币,但其编报的财务会计报告应当折算为人民币。()
法律手段是证券市场监管部门的主要手段,具有较强的威慑力和约束力。()
二十四节气是我国古代汉族劳动人民长期经验的积累和智慧的结晶。下列关于各个节气的说法,正确的是:
下列属于判断事项导致的特别风险是()。
用Word软件录入以下文字,按题目的要求完成排版后,用Word保存功能直接存盘。荷塘月色来自清曲曲折折的荷塘上面,弥望的是田田的叶子。叶子出水很高,像亭亭的舞女的裙。层层的叶子中间,零星地点缀着那些白花,有袅娜地开着的,有羞涩地打着
Peopleoftensaythatweshouldnotjudgeapersonbyhis(appear)______.
最新回复
(
0
)