中国东部浅水湖泊沉积物总氮总磷基准阈值研究

受人类活动的影响,东部浅水湖泊沉积物中总氮、总磷负荷很高,当外来污染源得到控制时,底泥中的营养盐会逐渐释放出来,对湖泊水质与生态系统影响很大。为合理削减湖泊内源污染,控制沉积物中营养盐向上覆水体释放,研究制定东部浅水湖泊沉积物总氮、总磷基准阈值,分别测定了100个湖泊的896个表层沉积物样品和8个典型湖泊11个柱芯的沉积物总氮（TN）、总磷（TP）含量,分析了沉积物TN、TP浓度剖面分布特征。通过频度分布法对100个湖泊沉积物总氮总磷的污染状况进行评价,通过背景值比较法确定了8个典型湖泊沉积物的TN、TP背景值。结果表明,100个湖泊的表层沉积物TN浓度范围在479.70~5 573.65 mg·kg-1,TP浓度范围在248.44~1000.33 mg·kg-1,不同湖泊表层沉积物中TN、TP值差异较大。8个典型湖泊沉积物总氮、总磷含量整体上表现出随着深度增加而下降变化趋势,在深层沉积物中含量保持稳定。所调查8个湖泊TN均值为1443.83 mg·kg-1,变化范围为247.45~3719.46 mg·kg-1,各湖泊中TN均值表现为：沱湖〉焦岗湖〉花园湖〉七里湖〉北民湖〉大通湖〉城东湖〉瓦埠湖;TP均值为519.62 mg·kg-1,变化范围为225.41~1944.89 mg·kg-1,各湖泊中TP均值表现为：北民湖〉大通湖〉七里湖〉焦岗湖〉沱湖〉瓦埠湖〉城东湖〉花园湖。不同湖泊沉积物总氮、总磷背景值差异很大。通过对100个湖泊表层沉积物TN、TP的频度分析发现,沉积物营养盐含量上25%点位对应的TP质量浓度398.51mg·kg-1,TN质量浓度为1106.24 mg·kg-1,沉积物营养盐含量下25%点位对应的TP质量浓度664.58 mg·kg-1,TN质量浓度为2916.66 mg·kg-1。通过互相之间的比较分析,推荐采用背景值比较法确定的各湖泊沉积物总氮、总磷背景值均值与频度分步法25%点位对应的总氮值和40%点位对应的总磷值作为东部浅水湖泊沉积物总氮、总磷基准阈值。因此,?

Study on sediment TN and TP criteria in eastern shallow lakes,China

The total nitrogen and phosphorus loads in the shallow lake sediments of eastern region are high due to anthropogenic activities. Nutrients in sediments may release into water column and affect water quality and ecosystem greatly after exogenous sources were controlled. In order to reduce endogenous source and establish sediment total nitrogen （TN） and total phosphorus （TP） criteria in eastern shallow lakes, China, 896 surface sediment samples in 100 lakes and 11 sediment cores in 8 typical lakes were collected to determine the contents of total nitrogen （TN）, total phosphorus （TP）, TN and TP concentration profiles in these samples were also analyzed. Background value comparison and frequency distribution methods were applied to evaluate TN and TP pollution status in sediments, respectively. The results indicated that TN and TP in 100 lakes of eastern lake region varied greatly, ranging from 479.70 to 5 573.65 mg·kg-1 and from 248.44 to 1 000.33 mg·kg-1, respectively. TN and TP in 8 lake sediment cores decreased gradually with depth, and maintained stable in deep layers. TN concentrations averaged 1 443.83 mg·kg-1, and ranged from 247.45 to 3 719.46 mg·kg-1, and the rank order of TN concentrations in 8 lake sediments was：Lake Tuo〉Lake Jiaogang〉Lake Huayuan〉Lake Qili〉Lake Beimin〉Lake Datong〉Lake Chengdong〉Lake Wabu. TP concentrations averaged 519.62 mg·kg-1, and ranged from 225.41 to 1 944.89 mg·kg-1, and the rank order of TP concentrations in 8 lake sediments was： Lake Beimin〉Lake Datong〉Lake Qili〉Lake Jiaogang〉Lake Tuo〉Lake Wabu〉Lake Chengdong〉Lake Huayuan. Calculated TN and TP background values in 8 typical lake sediments varied greatly. The frequency analysis results indicated that TN and TP in upper 25% lakes averaged 1 106.24 mg·kg-1 and 398.51 mg·kg-1, respectively, TN and TP in lower 25% lakes averaged 2 916.66 mg·kg-1 and 664.58 mg·kg-1, respectively. Through comparative analysis, average TN and TP background values using background value compariso