首页
登录
职称英语
Lead deposits, which accumulated in soil and snow during the 1960’s and 1970
Lead deposits, which accumulated in soil and snow during the 1960’s and 1970
游客
2024-02-22
41
管理
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 worldwide 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 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 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. [br] 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
根据题干中的authors of the Ambio定位文章第五段,选项A是尾句的同义表达。
转载请注明原文地址:https://tihaiku.com/zcyy/3472840.html
相关试题推荐
Leaddeposits,whichaccumulatedinsoilandsnowduringthe1960’sand1970
A、Hewasknockedoutduringonecontest.B、Helostthefinalchancetowinacha
Duringthepressconference,thereporters______someofthepresident’sstatem
Itisduringhersparetime______Jennyhasbeenstudyingcomputerprogramming.
Duringanearthquake,thegreatpartofdamageandlossoflifehasbeen______c
Itwaseasytobe______duringtheguestspeaker’spresentationbecauseshewa
Duringthelongwaiting,passengershadnothingtodobut______booksandmagazi
Theyhadapleasantchat______acupofcoffee.A、forB、withC、duringD、overD介词辨
[originaltext]Duringthepastdecade,therehasbeenamultifoldincreasei
[originaltext]Duringthepastdecade,therehasbeenamultifoldincreasei
随机试题
Ifyouarethinkingabout______tothebeachfortheweekend,don’tmissWBNC’su
Despitethegeneralnegativefindings,itisimportanttorememberthatall
—DidyoutellJuliaabouttheresult?—Oh,no,Iforgot.I______hernow.A、will
WithinEUprimaryeducation,aclearmajorityofpupilschoosetostudyEngl
WhytheWarAgainstTerrorWillBoosttheEconomyThereisstill
对学生体育学习的形成性评价,重点应放在()。A.学习基础 B.学习条件
关于人类胚胎干细胞研究的伦理原则不正确的是A:尊重原则 B:知情同意原则 C
民事合同可以分为诺成合同与实践合同。下列合同中,属于实践合同的是( )。A.买
投资项目净现值为零时所对应指标的收益率称为( )。A.利息备付率B.内部收益率C
企业应建立的安全承诺包括()等内容。A.安全价值观 B.安全愿景 C.
最新回复
(
0
)