普者黑河流-湖泊湿地表层沉积物磷素时空分布及影响因素

Spatial and Temporal distribution and factors influencing phosphorus in surface sediments of Puzhehei river and lake wetland,China

应用四步连续提取法和冗余分析(RDA),对总磷(TP)时空分布及各形态磷的环境影响因素进行深入探讨。结果表明:河流和湖泊湿地表层沉积物TP含量分别为415~1903、244~2474 mg·kg^-1,均为中度污染水平,响水河与中段湖区为高含磷区域,枯水期TP含量较丰水期和平水期要高;两类湿地表层沉积物中各形态磷含量排序为:铁铝氧化态磷(NaOH-rP)>难溶性磷(Res-P)>有机质结合态磷(NaOH-nrP)>可还原态磷(BD-P)>钙磷(HCl-P)>弱吸附态磷(NH4Cl-P)。其中,NaOH-rP、Res-P两者之和占TP比例达55.4%,而HCl-P、NH4Cl-P占TP均不足3%,潜在环境风险较高;从影响因素来看,NH4Cl-P受环境因子影响较大,BD-P、NaOH-rP与pH为负相关关系,与氧化还原电位(OPR)为正相关,总有机碳(TOC)的附着作用对NaOH-nrP的固定产生很大干扰,HCl-P与pH负相关,Res-P则相对稳定。

It is crucial to investigate the total phosphorus(TP)temporal and spatial distributions in the surface sediments and the factors affecting phosphorus species to understand the eutrophication of Puzhehei wetland. As such, the four-step continuous extraction and redundancy analysis were employed to study the TP spatial and temporal distributions and related factors. Our data showed that TP content in the surface sediments of rivers and lakes was 415~1903 and 244~2474 mg·kg^-1, respectively, indicating moderate pollution levels. However,TP content in both Xiangshui River and the middle lake showed higher levels as follows:low-water period > high-water period > normalwater period. In addition, the concentrations of phosphorus species in two wetlands were:NaOH-rP > Res-P > NaOH-nrP > BD-P > HClP>NH4Cl-P. The sum of NaOH-rP and Res-P accounted for 55.4%, whereas HCl-P and NH4Cl-P accounted for less than 3% of TP suggesting a high environmental risk. Moreover, NH4Cl-P was affected by environmental factors. BD-P and NaOH-rP were negatively correlated with pH, but positively correlated with oxidation-reduction potential(OPR)and the adhesion of total organic carbon(TOC)to NaOHnrP. HCl-P was negatively affected by pH. But, Res-P was relatively stable.