207 top soil samples were collected from Hebei province and the contents of heptachlor were measured.

在河北省境内采集207个表层土壤样品，测定其中的七氯含量。

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207 top soil samples were collected from Hebei province and the contents of heptachlor were measured.

在河北省境内采集207个表层土壤样品，测定其中的七氯含量。

youdao