小兴凯湖表层底泥磷吸附容量及潜在释放风险

利用沉积物磷吸附指数(PSI)和磷吸附饱和度(DPS)研究了小兴凯湖表层沉积物的磷吸附容量,分析了沉积物中磷的吸附饱和度(DPS)与其他指标的相关关系,并讨论了不同采样点湖泊沉积物中磷的潜在释放风险.结果表明:13个采样点的表层沉积物的PSI为9.78~197.53(mg?L)/(100g?μmol),平均值为59.77(mg?L)/(100g?μmol);DPS为9.95%~24.47%,平均值为15.41%.PSI与草酸铵提取的磷(Pox)极显著正相关,与草酸铵提取的铁、铝(Feox,Alox)显著正相关,草酸铵提取的铁是影响PSI的主导因素;DPS主要受沉积物中原有吸附态磷的影响.此外,磷释放风险指数(ERI)8.99%~129.94%的计算结果表明:小兴凯湖表层沉积物中磷释放诱发富营养化的风险处于高度风险范围,其中,受农业面源污染影响较大的北岸区域相比其他区域发生富营养化的风险更高.

Phsophorus sorption capacity of surface sediments and risk assessment of potential phosphorus release in Lake Xiaoxingkai,China

Phosphorus sorption capacity of surface sediments are estimated by phosphorus sorption index (PSI) of sediments and degree of phosphorus saturation (DPS) in Lake Xiaoxingkai, China. The relationship between DPS and other indicators were analyzed, and the risk of potential phosphorus release were discussed by calculating phosphorus release risk index (ERI). The results showed that PSI ranged from 9.78 to 197.53 (mg?L)/(100g?μmol), with an average of 59.77 (mg?L)/(100g?μmol). DPS ranged from 9.95% to 24.47%, with an average of 15.41%. PSI was significantly and positively correlated to phosphorus (Pox), iron (Feox) and aluminum (Alox) extracted from sediment by ammonium oxalate. Rion extracted from sediment by ammonium oxalate might be the main factor to affect PSI. DPS was influenced mainly by original adsorbed phosphorus of sediments (or Pox). In addition, ERI ranged from 8.99% to 129.94%, which indicated that the Lake Xiaoxingkai might be in high potential eutrophication risk due to the release of phosphorus from surface sediments. Compared to the different sample points, the north area polluted by agricultural non-point source pollution has higher potential eutrophication risk than other areas.