Mercurial exhalations

Oak Ridge National Laboratory (ornl) researchers in the US have theorised that mercury in soil gas is absorbed by plants when the plants ' mercury level is low. But when their mercury level rises and the level present in the air decreases, plants release some of their mercury into the air. Meteorological data from Walker Branch Watershed in Oak Ridge have shown significant emissions of mercury from oak, hicory and maple trees. Studies have also shown that wet trees received mercury from the air, but when they dried they emitted significant amounts of mercury (ornl Review, Vol 29, No 1 & 2).