Mobility of N and P in Phosphogypsum Pile and its Impact on Surface Water Quality in Guizhou Province, Southwestern China

Abstract

In order to evaluate the impacts of N and P mobility from phophogypsum on surface water quality, the dissolved N and P concentrations in the drainage and river waters nearby phophogypsum piles were investigated at the phosphoric acid plant regions in central Guizhou Province, and batch leaching tests for the phophogypsum was performed. The results shown that the concentrations of NH4+ and PO43− in leachate solutions from phophogypsum were 0.325~0.587 mg L−1 and 148.6~266.0 mg L−1, respectively, and higher concentrations of NH4+ (2.86~8.02 mg L−1) and PO43− (201.9~1195.6 mg L−1) in the drainage waters from phophogypsum pile. In phosphoric acid plant areas, the concentrations of NH4+ and PO43− in the stream waters nearby phophogypsum piles were 0.96~2.36 mg L−1 and 1.26~4.89 mg L−1, respectively, as indicated by high concentrations of NH4+ and PO43−, suggesting a eutrophication problem for surface water nearby phophogypsum piles in those areas.