在《人类环境杂志》上发表的一项研究称，科学家们发现，自引进无铅汽油以来，美国东北部土壤中的铅含量已经显著下降。

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.

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但是，这些企业越来越多的把研究转移到了美国，那里的回报更丰富，环境也更具有激发性。

Increasingly, however, they are moving research to America because the rewards there are greater and the environment is more stimulating.

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碳品联合企业已经开始实施他们长达一年的咨询工作，而本月在美国大学环境变化研究院举行的会议中更是探讨了如何为泰斯科公司的产品增添碳质标签。

The Carbon Trust has begun a year-long consultation and this month a meeting took place at the Environmental Change Institute at Oxford University, which is looking into carbon labelling for Tesco.

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