Flue Gas Desulfurization Gypsum Effects On Soil, Pasture Plants, and Earthworm Chemical Composition.

Approximately 12.3 million short tons of flue gas desulfurization (FGD) gypsum were produced in 2007 by power plants to reduce S emissions. Gypsum amendments can improve the physical and chemical properties of soils by promoting soil aggregation and water infiltration rates and mitigating Al toxicity of subsoil acidity. However, there are concerns about environmental effects when FGD gypsum is used as a soil amendment, and there are few reports on how chemical properties of soils, plants and animals are affected following FGD gypsum application. FGD gypsum and mined gypsum were surface-applied at rates of 0 and 20 Mg ha^-1 to a pasture that had an acidic subsoil. Concentrations of 29 elements in soil, soil water, plant tissue and earthworms were measured. Results indicate that concentrations of Ca and S were increased in plant tissue, soil, and soil water, and the concentrations of Al and Fe were decreased in plant tissue by both gypsums. Preliminary results also show that concentrations in earthworms of most environmental concern elements were not affected by either gypsum sources, but concentrations of Ca, S and Hg were increased by both FGD gypsum and mined gypsum.