Minesoil response to reclamation by using a flue gas desulfurization product

Mine lands are an environmental concern worldwide because of their potential strong negative impact on water and soil quality. A field study was conducted to assess the use of a dry flue gas desulfurization (FGD) product for reclamation of an abandoned surface coal mine in Ohio. The FGD product was an atmospheric fluidized bed combustion residue and was applied to the graded mine site at 280 Mg ha^-1, both alone and in combination with 112 Mg ha^-1 yard waste compost, and was compared with conventional reclamation with 20 cm of borrow soil plus 157 Mg ha^-1 of agricultural limestone. A grass-legume sward was planted, and soil physical and chemical properties and β-glucosidase activity were measured over both short- (1-4 yr) and long-term (15-17 yr) periods following reclamation. Soil pH at 0- to 20-cm depth increased from 3.1 to approximately neutral and was sustained at this level for 15 yr. Compared with the conventional reclamation, extractable Ca, S, B, and Zn concentrations at 0-to 20-cm depth were generally increased by the treatments with FGD product, while other extractable trace metals measured were generally not increased in short- or long-term measurements. Seventeen years after reclamation, β-glucosidase activity had increased in all three treatments at 0- to 5- and 5- to 10-cm depths compared with an adjacent untreated area. Furthermore, β-glucosidase activity more than doubled in the treatments with FGD product compared with the conventional soil treatment at 0- to 5-cm depth. These results suggest that the use of high lime FGD products for reclamation of acid coal mine lands can provide effective long-term reclamation.