Project Number: 1245-12000-040-23
Project Type: Reimbursable

Start Date: Dec 20, 2011
End Date: Dec 19, 2013

Objective:
Evaluate the benefit of FGD-gypsum in revegetation and reduction of Hg vapor emissions from CA mercury mine waste contaminated serpentine soil materials. These soils are estimated to cause at least 50% as much Hg emission as all U.S. coal-fired power plants. Prevention of Hg emission from the mine wastes could be an important environmental benefit (in addition to cessation of waterway contamination) which might be traded for reduced emission goals from power plants.

Approach:
Conduct greenhouse trial of mixtures of FGD-Gypsum and other locally (mid-CA) available soil amendments (composts, biosolids, manures) which might be useful in establishing persistent vegetative cover on Hg mine wastes and geochemically Hg rich soils from CA. Because these soils are extremely deficient in Ca, addition of gypsum is expected to strongly aid vegetation establishment and persistence. Effective cover would prevent sunlight from hitting the soil (which causes photo-reduction of Hg2+ in soil which allows the Hg vapor release from the mine waste. Climate-adapted vegetation would be used in the test. Hg vapor emissions of the surface amended and control soils will be measured and compared to controls. Evaluation of the nutrition of plants from several treatments will help characterize how well the amendment mixtures should support persistent revegetation of these mine wastes.