Submitted to: Agro-Environment Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 2/26/2010
Publication Date: 5/18/2010
Citation: Norton, L.D. 2010. Mercury Concentrations in Plant Tissues as Affected by FGDG Application to Soil [abstract]. Agro-Environment Symposium. May 19-22, 2010, Cancun, Mexico. 2010 CDROM.
Technical Abstract: Flue Gas Desulfurization Gypsum (FGDG) is produced by reducing sulfur dioxide emissions from themo-electric coal-fired power plants. The most common practice of FGDG production may trap some of the Mercury (Hg) present in the coal that normally would escape as vapor in the stack gases. Concern for the environment and particularly the fate of this Hg when FGDG is used in agriculture has been a concern for the US Environmental Protection Agency recently. In order to evaluate the problem, we conducted field studies at two locations where FGDG was compared to pelletized mined gypsum (PG) and a control. The rates used varied between 0 and 6.72 MT ha-1. Various crops were grown in the field using recommended agricultural practices and fertility recommendations. In 2008, corn tissue was sampled at the silking stage from the ear leave and at harvest for the total plant. Grain was also collected for analyses of Nitrogen (N), Carbon (C), Sulfur (S) and Hg. In 2009, soybean tissues at flowering and alfalfa forage samples at the first cutting after FGDG and PG application were collected for the same analyses. The only significant difference found was an increase in Hg concentration for corn ear leaf samples when 2.24 MT ha-1 FGDG was applied. At harvest, neither the mature corn stover nor grain had any significant difference in Hg concentration with FGDG application. Sulfur increased in alfalfa with the rate of FGDG applied but not for PG although yields did not increase. Although N or C contents were not statistically different the increase in S content may be the result of higher protein content. Application of FGDG to agricultural crops at the rates used does not represent a significant risk of getting Hg into the food chain.