This had similar mercury levels to the phloem.

树皮的汞含量与韧皮部相近。

He and his colleagues came up with a practical way to determine the scope of mercury contamination in an ecosystem by measuring mercury levels in a single species.

他和他的同事们想出了一种实用的方法，通过测量单一物种的汞水平来确定生态系统中汞污染的范围。