急!请大家 人工 帮忙翻译一下 谢谢!
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 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.
我这有机器翻译的你可以参考一下：
铅存款,——累积在土壤和雪中1960的,70的,主要地结果的含铅汽油汽油废气起源配偶探视.时间状语那根据清洁空气法委任统治了无铅汽油使用配偶探视,铅积累全世界减少了意味深长地.
一个论文发布最近在美国自然杂志节目,空气传播含铅气体汽油废气从美国是铅贡献者铅的高浓度在雪中在格陵兰.新的书房是一个结果的继续研究领导由.博士查尔斯boutron,一个专家在重金属的碰撞在环境在来源于法国的在法国.一个论文由.博士boutron发布1991年显示那铅水平在北极的的雪在下降.
在他的新论文,.博士boutron发觉比率的引导入内的不同形式含铅汽油使用配偶探视欧洲的的异于比率,亚洲人和加拿大人汽油因此区分铅源.优势铅比发觉在格陵兰雪配那个勘查在汽油从美国.
在一个论文发布在日记国际环境研究,科学家发觉,铅水平在土壤在美国东北部已经减少了显着自从介绍的无铅汽油.
多科学家已经相信了铅将留在土壤和雪为一个悠久期间.
作者的国际环境研究研究审查帮的样本土地的表层从同一30的现场森林楼在新英格兰,纽约,宾夕法尼亚1980年,1990年.森林环境处理,重新分配铅比科学家更快速已经期望了.