Comparison among soil additives for enhancing Pteris vittata L.: Phytoremediation of As-contaminated soil

Pot experiments were conducted to assess the effects of monoammonium phosphate (NH₄H₂PO₄) and citric acid (CA) on the arsenic uptake of Chinese brake fern (Pteris vittata L. in two typical arsenic-contaminated soils i.e. fluvo-aquic and brown) from Jiyuan (JY) City and Baoding (BD) City in Northern China. NH₄H₂PO₄ improved the biomass of P. vittata, whereas CA exerted no significant influence. NH₄H₂PO₄ and CA both increased the arsenic uptake of P. vittata by 6.08 and 2.72 times, respectively, in fluvo-aquic soil and 4.20 and 2.52 times, respectively, in brown soil. Moreover, CA, but not NH₄H₂PO₄, promoted the transfer of arsenic from the root to the frond. NH₄H₂PO₄ and CA increased Olsen's arsenic contents in the soils and promoted the transformation of residual arsenic and crystalline Fe/Al oxide-bound arsenic to nonspecifically and specifically sorbed arsenic. This study proved that P. vittata can be used in Northern China. Applying NH₄H₂PO₄ and CA can enhance the effectiveness of P. vittata in the phytoremediation of arsenic-contaminated soils.