28条环太湖河流沉积物氮的分布特征

Distribution Characteristics of Nitrogen in Sediments of 28 Rivers Around Tai Lake,China

测定了太湖流域不同污染控制区中28条主要环湖河流河口处表层0～10cm沉积物中氨氮(NH3-N)、硝氮(NO-3-N)、有机氮(Org-N)及总氮(TN)含量,揭示氮的空间分布并分析各形态氮之间的相关性。结果表明,环湖河流表层沉积物中TN含量由高到低依次为东部污染控制区>北部区>湖西区>浙西污染控制区,平均958.70mg.kg-1,且以东部污染控制区中吴溇河口最高,污染最重。NH3-N含量远高于NO-3-N,平均200.29mg.kg-1;Org-N含量及分布与TN相似,平均758.40mg.kg-1,占TN的39.27%～95.12%。NH3-N是可交换态氮(EN)的主要存在形式,Org-N是沉积物中氮的主导形态,沉积物中TN只有极少部分在成岩过程中发生矿化。

In order to reveal spatial distribution characteristics of nitrogen in the surface （0-10 cm ） sediments of 28 main rivers in different pollution regions around Tai Lake, the content of ammonia nitrogen （NH3-N）, nitrate nitrogen （NO3-N）, orgamic nitrogen （Org-N） and total nitrogen（TN ） of these surface sediments samples were determined. The correlation of various nitrogen forms has also been analyzed. The re- sults showed that the content of TN from high to low in order was ： eastern pollution control region〉northern pollution control region〉pollution control region of western Tai Lake〉pollution control region of western Zhejiang Province, which was 958.70 mg. kg-1 in average. The highest content of TN was located in Wulou River in eastern pollution control region, with the most serious pollution problem. The average content of NH3-N and Org-N were 200.29 mg. kg^-1 and 758.40 mg.kg^-1 respectively. The content and distribution of Org-N were very similar with TN, accounting for 39.27% to 95.12% of it. Org-N was the dominant form of nitrogen in sediments. That only a very small part of TN in sediments could be mineralized during diagenesis has also been proved.