We have stressed that heavy metals will be found in groundwater due to cracks in the ground where magma has forced up, and due to volcanic ash that has washed down with the rain.

我们强调过由于地面的破裂岩浆被迫上升，和随雨降下的火山灰，地下水中会存在重金属。

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Miners can use underwater robots to dig up deposits left from "black smokers, " which are little towers of metallic sulfides that form after magma forces fluids with copper, gold and other metals through the seafloor.

WSJ: Exhausting the Earth's Resources? Not So Fast