Alkali soil reclamation with flue gas desulfurization gypsum in China and assessment of metal content in corn grains

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.