摘要
利用滇池53个表层沉积物样品,研究了其不同形态氮含量及空间分布特征,探讨了滇池沉积物氮潜在矿化能力及其污染特征,以期揭示滇池沉积物氮污染影响因素及沉积物氮释放风险.结果表明:1滇池全湖表层沉积物总氮(TN)平均含量为3 515.60 mg·kg-1,其中草海北部疏挖区、盘龙江入湖口及海口入湖区域含量较高,宝象河河口疏挖区域TN含量相对较低;总有机氮(TON)含量较高,占TN的85.86%;溶解态无机氮(DIN)含量较低,占TN的14.10%,TON与TN空间分布趋势一致,而DIN则不同;与我国其他湖泊相比,滇池沉积物氮含量已经处于较高水平,其污染程度仅低于污染严重的城市湖泊;2滇池全湖表层沉积物潜在可矿化氮(PMN)平均含量1 154.76 mg·kg-1,占TN的32.90%,潜在释放风险较大;其中草海湖区、外海北部盘龙江入湖口湖区、中部洛龙河和梁王河入湖口湖区及白鱼口湖区显著高于其它湖区;目前滇池p H值有利于其沉积物氮矿化,有机质通过释放NH+4-N影响其沉积物氮矿化;污染较重的水域,滇池上覆水氮浓度受其沉积物氮矿化影响较大,而污染较轻水域,则受影响较小.
The nitrogen content,its different forms and their spatial distribution were studied by using the 53 sediment samples from different sites in Dianchi Lake. Thereafter, the potential nitrogen mineralization ability of the sediments and their pollution characteristics were also explored to understand the influencing factors of nitrogen pollution and its release risk from the sediment surface to the overlying water of Dianchi. The results showed: 1 the average total nitrogen content of surface sediment in Dianchi Lake was 3 515. 60 mg·kg- 1,which was at a high level from the inlets in Caohai Northeast thinning digging area,Panlong River and the Haikou into Dianchi Lake,but relatively low in Baoxiang River Estuary dredging area. The total organic nitrogen( TON) content,accounting for 85. 86% of TN,was at a high level; on the other hand,the dissolved inorganic nitrogen( DIN) content was lower,which accounted for 14. 10% of TN. The spatial distribution of TON and TN kept the same trend,but not the DIN. Compared with other Lakes of China,the nitrogen content of sediment in Dianci was at a high level,and the extent of pollution was just below the serious polluted City Lakes. 2 The average potential mineralizable nitrogen( PMN) content of Lake Dianchi was 1 154. 76 mg·kg- 1,accounting for 32. 90% of TN,which raised the potential risk of its release into the overlying water. Higher PMN was found in the Caohai Lake area and the inlet of Panlong River in the North,the inlet of Luolong Rive in the Middle Lake,the inlet of Baiyukou Lake and Liangwang River in the South. Nowadays,the p H value of Dianchi Lake was favorable for its sediment nitrogen mineralization,and its nitrogen mineralization was affected by the release of NH+4-N from organic matter. In the heavy polluted area,the concentration of the overlying water nitrogen was seriously affected by nitrogen mineralization of sediment from Dianchi,while the light polluted area was less affected.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第2期471-480,共10页
Environmental Science
基金
国家自然科学基金项目(U1202235)
国家水体污染控制与治理科技重大专项(2012ZX07102-004)
关键词
氮形态
空间分布
矿化能力
滇池
表层沉积物
nitrogen forms
spatial distribution
mineralization capacity
Dianchi Lake
surface sediment
