摘要
通过现场调查和室内模拟试验,对洱海具有代表性的9个表层沉积物样品中w(TN)的分布特征以及沉积物中NH4+-N释放动力学特征进行了研究.结果表明,洱海表层沉积物中w(TN)在2.084 4～6.515 3 gkg之间,平均值为3.537 8 gkg,北部西岸为高值区,南部(靠近大理市)为次高值区.一级动力学模型可很好地拟合洱海表层沉积物NH4+-N释放动力学特征,NH4+-N最大释放量在0.120 9～0.281 0 gkg之间;释放主要集中在0～5 min内,约占最大释放量的68%～83%;随后释放速率逐渐放缓,到120 min后基本达到释放平衡.运用无限稀释法对沉积物NH4+-N释放潜能进行测定表明,洱海沉积物NH4+-N释放潜能在1.700 1～3.587 9 gkg之间,在水土质量比约为2 500时,NH4+-N释放量达到最大,随后释放逐渐趋于平衡.洱海沉积物NH4+-N释放潜能及最大释放量均与其w(TN)呈显著正相关.洱海沉积物中w(TN)与NH4+-N释放潜能和最大释放量均高于长江中下游湖泊,具有较大的氮释放风险.
The distribution status and release characteristics of nitrogen were investigated by studying on release kinetics characteristics and release potential ability change of the total nitrogen content and ammonia nitrogen （ NH4 ~ -N） for nine sediment samples collected from Erhai Lake. The results indicated that the total nitrogen content in the sediments varied from 2. 0844 to 6. 5153 g/kg with the mean value of 3. 5378 g/kg. The area with the highest total nitrogen is located in the west bank of the north section and the second high area is located in the south part near Dali City. The release kinetics of NH4 ＋ -N in the sediment surface was well simulated by the first-order kinetic equation. The greatest amount of the released NH4 ~ -N was between O. 1209 and 0. 2810 g/kg. The release process of NH4＋ -N was mainly occurred within the first five minutes and its amount was accounted for 68%-83% of the greatest amount. After 120 minutes, this release process was gradually reached to its balance. The release potential ability of NH4＋ -N was between 1. 7001 and 3. 5879 g/kg, and the release potential ability of NH4＋ -N reached to the maximum value, when the ratio of water and soil approximately was 2500 ： 1. The total nitrogen content, the release potential ability of NH4 ^-N and the greatest amount of NH4＋-N reached in sediment samples of Erhai Lake were higher than that of the sediments from the lakes in the middle and lower reaches of the Yangtze River region. This result indicated that the sediments from Erhai Lake had a risk of nitrogen release greater than those from the lakes in the middle and lower reaches of the Yangtze River region.
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2013年第3期256-261,共6页
Research of Environmental Sciences
基金
国家自然科学基金项目(U1202235
41103070)
国家水体污染控制与治理科技重大专项(2012ZX07105-005)
关键词
洱海
沉积物
氮含量
氨氮释放
Erhai Lake
sediment
nitrogen content
release of ammonia nitrogen
