28条环太湖河流沉积物氮的分布特征

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。

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

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),organic 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 results 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.