There is generally a significant heterogeneity in the vertical distribution of mobile phosphorus (P) in sediments, but the previous studies concerning the effect of zirconium-modified zeolite (ZrMZ) addition on the mobilization of P in sediments neglected this feature. In this study, microcosm experiments were conducted to investigate the effect of ZrMZ addition on the mobilization of P in river surface sediments at different depths. A high-resolution diffusive gradients in thin films technology (DGT) was used to measure the concentration of labile P in the overlying water-sediment profiles at a submillimeter vertical resolution. Results showed that the ZrMZ amendment not only could reduce the concentration of soluble reactive P (SRP) in the overlying water, but also could decrease the concentrations of SRP in the pore water at different depths. Furthermore, the ZrMZ amendment resulted in the reduction of both the releasing flux of SRP from sediments to the overlying water and the diffusion flux of SRP from the pore water to the overlying water. After the addition of ZrMZ into the top sediment, the static layer with low DGT-liable P (DGT-P) concentration was observed in the upper sediment. The addition of ZrMZ into the upper sediment resulted in the reduction of mobile P (P_m) in the upper and lower sediments via the transformation of P_m to more stable NaOH-extractable P (NaOH-rP) and residual P (Res-P). In addition, the contents of bioavailable P (BAP) including water-soluble P (WSP), readily desorbable P (RDP) and iron oxide paper extractable P (FeO-P) in the upper sediment were greatly reduced by the ZrMZ addition. Results of this study show that the immobilization of pore water SRP, DGT-P, sediment P_m and sediment BAP by ZrMZ played a very important role in the control of P release from sediments to the overlying water by the ZrMZ amendment.

沉积物中活动性磷（P）的垂直分布通常存在显着的非均质性，但是先前有关锆改性沸石（ZrMZ）添加对沉积物中P的迁移影响的研究忽略了此特征。在这项研究中，进行了微观实验，研究了ZrMZ添加对不同深度的河面沉积物中P迁移的影响。薄膜技术中的高分辨率扩散梯度（DGT）用于在亚毫米垂直分辨率下测量上覆水沉积物剖面中不稳定P的浓度。结果表明，ZrMZ修饰剂不仅可以降低上覆水中可溶性反应性P（SRP）的浓度，而且可以降低不同深度的孔隙水中SRP的浓度。此外，ZrMZ修正不仅减少了SRP从沉积物到上覆水的释放通量，而且减少了SRP从孔隙水到上覆水的扩散通量。在顶部沉积物中添加ZrMZ之后，在上部沉积物中观察到具有低DGT活性磷（DGT-P）浓度的静态层。在上层沉积物中添加ZrMZ导致流动态P（P_米）在经由P的变换上下沉积物_米到更稳定的NaOH提取P（氢氧化钠-RP）和残余P（RES-P）。此外，通过添加ZrMZ，大大降低了上部沉积物中生物可利用的P（BAP）的含量，包括水溶性P（WSP），易解吸的P（RDP）和氧化铁纸可提取的P（FeO-P）。这项研究的结果表明，ZrMZ固定化孔隙水SRP，DGT-P，沉积物P _m和沉积物BAP在ZrMZ修正剂控制从沉积物向上层水中的P释放中起着非常重要的作用。