Release of Volatile Mercury from Vascular Plants

Abstract

AbstractVolatile, organic solvent soluble mercury has been found in leaves and seeds of several angiosperms. Leaves of garlic vine (Pseudocallyma alliacium), avocado (Persea americana) and haole‐koa (Leucaena glauca) release mercury in volatile form rapidly at room temperature. In garlic vine, the most active release is temperature dependent, but does not parallel the vaporpressure temperature relationship for mercury. Mercury can be trapped in nitric‐perchloric acid digestion fluid, or n‐hexane, but is lost from the hexane unless the acid mixture is present. Seeds of haole‐koa also contain extractable mercury but volatility declines in the series n‐hexane (90%) > methanol (50%) > water (10%). This suggests that reduced volatility may accompany solvolysis in the more polar media. Gas chromatographic analysis shows that the volatile compound is not dimethyl mercury.