小尚泡柱状沉积物营养盐分布特征和污染评价

Distribution Characteristics and Pollution Assessment of Phosphorus Forms in Xiaoshangpao Columnar Sediments

该文以取自连环湖小尚泡湖心的柱状沉积岩芯为研究对象,采用SMT连续分级提取法测定了柱状沉积岩芯中总磷(TP)及各形态磷的浓度,结合有机质(OM)、总氮(TN)、粒度和沉积年代的测定,研究了该湖泊自1940年以来沉积物各形态磷的演化历史,并对柱状沉积岩芯的污染状况进行评价。结果表明,柱状沉积物TP浓度范围是163.09~526.33 mg/kg,平均值为298.77 mg/kg,IP是TP的主要组成,Ca-P是IP的主要组成。在1964年以前TP、Ca-P和IP浓度随深度的变化波动较大,有2次明显降低阶段。1964-1982年,各形态磷、OM、TN浓度变化较稳定。1982-2009年,各形态磷浓度波动幅度较大,均有较大幅度的增加。磷元素的来源包括自然来源和人为输入,连环湖小尚泡沉积物磷元素的人为输入主要以生活污水的排放和农药化肥的流失为主。应用单项污染指数法对沉积物进行污染评价,评价结果表明TP在近表层存在一定的安全风险。

The columnar sedimentary cores from the middle of Xiaoshangpao Lake in Lianhuanhu Lake are taken as the research object.The concentration of total phosphorus(TP)and various forms of phosphorus in the columnar sedimentary cores are measured by SMT continuous classification extraction method.Combined with the determination of organic matter(OM),total nitrogen(TN),grain size and sedimentary age,the evolution history of various forms of phosphorus in the sediments of the Lake since 1940 is studied,and the pollution of sedimentary core was evaluated.The results show that the concentration range of TP in the column sediment is 163.09~526.33 mg/kg,with an average value of 298.77 mg/kg.IP is the main component of TP and Ca-P is the main component of IP.Before 1964,the concentrations of TP,Ca-P and IP fluctuated greatly with the depth,and there were two obvious decreasing stages.From 1964 to 1982,the concentrations of phosphorus,OM and TN were stable.From 1982 to 2009,the concentration of various forms of phosphorus fluctuated greatly,with a significant increase.The sources of phosphorus include natural sources and human inputs.The human inputs of phosphorus in Xiaoshangpao sediments of Lianhuanhu Lake are mainly the discharge of domestic sewage and the loss of pesticides and fertilizers.The single pollution index method was used to evaluate the sediment pollution.The results show that TP has a certain safety risk in the near surface.