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
42
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
ThousandsofEnglishwords______________________(源自拉丁文).
Duringthelast2years,manynewfactories______________________(涌现出来)alloverthetown.
Wecanmakeupourmindsaboutsomepeoplewithinonlysevensecondsofmeetingthem.Accordingtotheauthor,ifyouusuallyf
Accordingtothepassage,whatwasbadlyneededtoimproveindustrialefficiency?CharlesBabbage,anEnglishacademic,______.
A、AFrenchword.B、AChineseword.C、AnIndianWord.D、ASpanishword.CWheredidtheword"Canada"comefrom?
A、HetaughtEnglishinChicago.B、Hewascrippledinacaraccident.C、Heworkedtobecomeanexecutive.D、Hewasbornwithali
A、Eighty.B、Eighty-six.C、Sixty-eight.D、Forty-three.DW:Iassumethetrafficinthecityisbadduringtherushhourwhenpeop
A、Agriculturalproducts.B、Manufacturedfoods.C、Settlers.D、Farmanimals.AWhatwasusuallytransportedfromwesttoeast?
A、He’llprobablyneverfinishwritingthatpaper.B、He’llfinishitthedayaftertomorrow.C、Heworksonlyduringtheday.D、He
随机试题
设有两个表:学生(学号,姓名,性别)和成绩(学号,课程,成绩),若要查询每个男生各门课程的成绩情况,则可实现的操作是_______。
影响粮食中霉菌发育的重要因素有
患儿,4个月。开始添加辅食,近日来大便次数增多,量多质稀,味酸臭,夹有食物残渣,一般情况可,小便无明显减少。以下处理方法中恰当的是
生产、销售劣药,后果特别严重的,追究刑事责任时可
下列关于政府预算的表述,正确的有()。
马斯洛需要层次理论。(华东师范大学、宁波大学、中山大学)
A、 B、 C、 D、 B
DadCan’tHandleTheseToysAnyparentwithachild【C1】____theagesof3and11cantellyou【C2】____technologyhascreptint
TVissooftenaparent’sgoodfriend,keepingkidshappilyoccupiedsothegrownupscancookdinner,answerthephone,ortake
Excitingnewresearchindicatesthatgrowingoldermightnotnecessarilymeangrowingmentallyslower.Newstudiesareproviding
最新回复
(
0
)