Exploratory drilling in the area looked for tin, copper, zinc and other trace metals.

The carbon dioxide binds with calcium salts and trace metals such as nickel or zinc that otherwise make the material harmful to surrounding soil and water.

The trace metals may pose a danger if used on edible plants, as they can bioaccumulate.

Ash contains trace metals that, while in low concentration, provide nutrients to microorganisms that live in the water column.

Foremost among them was inductively coupled plasma-atomic emission spectroscopy, which could rapidly and simultaneously detect up to 40 different trace metals from a small sample.