外源硫酸盐对武汉墨水湖沉积物磷迁移的影响

Effect of External Sulfate on Phosphorus Migration of Sediment from Lake Moshui in Wuhan

对武汉市重污染湖泊——墨水湖沉积物及上覆水进行6周的室内模拟实验。结果表明,硫酸盐输入后促使上覆水中pH上升,而Eh出现下降。3周后外源硫酸盐在上覆水和沉积物间隙水中降至很低水平。SO2-4增强了有机质的分解,同时刺激了沉积物磷的释放,其释放量为沉积物上层>中层>下层,其浓度严重超过了富营养化水平。整体上,无机磷的含量占总磷的80%。上覆水和沉积物间隙水中溶解性活性磷(SRP)与SO2-4呈负相关,外源硫酸盐还原过程中因促进沉积物中磷的释放迁移,增加了湖泊上覆水的磷浓度水平。

A six-week experiment was conducted under simulated condition with the samples from Lake Moshui in Wuhan,aiming to explore the influence of external sulfate on phosphorus release.The results showed that pH in the overlying water increased and Eh decreased due to the input of sulfate.The diffusion of sulfate into the sediments promoted the decomposition of organic matter and it also stimulated the release of sediment phosphorus,especially inorganic phosphorus release.The upper layer sediments showed maximum release amount,followed by the middle layer sediments and the lower layer sediments.The phosphorus concentrations of the pore water exceeded the level of eutrophication.On the whole,the content of inorganic phosphorus accounted for 80% of total phosphorus.It suggested that external sulfate could promote the migration of phosphorus in the sediments and raised the phosphorus concentration in overlying water.