Alkali Soil Reclamation with Flue Gas Desulfurization Gypsum in China and Assessment of Metal Content in Corn Grains

Abstract

Abstract Flue gas desulfurization gypsum (FGDG), the by-product of wet and semi-dry desulfurization processes, has been used as an alkali soil amendment in China. We evaluated the change in soil properties, agricultural production and the safety of FGDG as a soil amendment. As a result, soil pH and ESP (exchangeable sodium percentage) decreased and corn production increased in FGDG-treated plots. The metal (B, Cr, Mn, Ni, Cu, As, Cd, Pb) contents in soil, FGDG, and corn grains were quantified by ICP-MS. Consequently, the contents of almost all metals in FGDG were lower than in soil. Moreover, the contents of almost all of the metals in the corn grains in the FGDG-treated plots were almost the same or lower than those in the control plot. Statistical analysis indicated that there was no effect of gypsum application on the metal content in the corn grains. Almost all of the metal contents were lower than the standard values set by FAO/WHO for human intake. The results showed that the FGDG from wet and semi-dry FGD processes is suitable as an alkali soil amendment. Keywords: Air pollutionby-productcoal combustiondesertificationfly ashsulfur dioxide Acknowledgement We would like to thank Mr. Ke Zhen Wang of the China Shenyang Economic Relations & Trade Office in Japan for establishing our contact with the Chinese researchers during the final drafting of the manuscript. We would like to express our appreciation to Dr. Soul Chun and Mr. Yoshinori Takagi for their assistance in obtaining the experimental data. We also thank the Science and Technology Commission of Shenyang Municipal Government. This work was supported by CREST of JST (Japan Science and Technology). Reviewers provided excellent suggestions for improving the manuscript. Notes a FGDG from wet process. b FGDG from semi-dry process. c No gypsum application. a FGDG from wet process. a pH was measured at a gypsum to water ratio of 1:10. a This is gypsum from a wet desulfurization process that has been used since 1996. b,d These gypsums are the by-products of wet and semi-dry desulfurization processes, respectively, and were used in Field 1. c This is gypsum from a wet desulfurization process and was used in Field 2. a Tolerable Intake (TI). b Daily human intake through food. c Mean dietary intake. d Provisional Tolerable Weekly Intake (PTWI). ∗The value was calculated based on a person with a body weight of 60 kg.