7条环太湖河流沉积物氮含量沿程分布规律

2009年9月采集7条主要环太湖河流沿程37个断面的沉积物样,测定了表层沉积物中总氮(TN)、氨氮(NH4+-N)、硝氮(NO3--N)和有机氮(ON)含量,揭示分布特征,旨在为太湖水体富营养化防治提供基础数据.结果表明,这些表层沉积物TN平均1 303.49 mg.kg-1,最大和最小值分别在社渎港和长兜港;NH4+-N和ON的空间分布与TN基本一致,其平均含量分别为221.57 mg.kg-1和1 095.71 mg.kg-1,各沉积物中NO3--N含量较低,均不足TN的1%,平均含量0.79 mg.kg-1.7条河流沉积物整体上以ON为主,NH4+-N为无机氮主要存在形式,多数河流表层沉积物氮含量沿程变化明显.

Speciation Distribution of Nitrogen in Sediments of 7 Rivers around Taihu Lake

Totally 37 surface sediments were sampled from the different sections of 7 main rivers around Taihu Lake at September 2009.The contents of total nitrogen, ammonia nitrogen, and nitrate nitrogen in these samples had been determined, and the nitrogen speciation distribution in sediments of the rivers had been analyzed. Aim of this study was to provide basic information for prevention and control of the eutrophication of Taihu Lake. The obtained results showed that the average content of total nitrogen was 1303.49 mg·kg^-1, with the highest value occurred at Shedugang River and lowest value at Changdougang River, respectively. Ammonia nitrogen and organic nitrogen in sediments had a similar distribution with total nitrogen. Ammonia nitrogen accounted for 17% of the total nitrogen with the average content of 221.57 mg·kg^-1, and organic nitrogen accounted for 84.06%, with the average content of 1095.71 mg·kg^-1. However, nitrate nitrogen content in the sediments was relatively low, accounting for not more than 1% of total nitrogen. Generally, the nitrogen distribution in sediments of the investigated rivers was characterized by the fact of organic nitrogen was the main form and inorganic nitrogen was dominated by ammonia nitrogen. The nitrogen contents in most river sediments changed significantly with the distance to river source, reflecting different pollution characteristics.