Effect of environmental changes on nitrogen release from sediments in polluted urban river
-
摘要: 以苏州市古城区劣Ⅴ类水体为研究对象,利用模拟试验方法,研究和探讨了水体环境条件(DO、Eh、pH值、温度)变化和疏浚深度对河道底泥氮释放的影响.底泥供试样中NH4+-N与NO3--N含量一般为0.277 g/kg与0.0012g/kg,上覆水体NH4+-N与NO3--N含量一般为6.743 mg/L与1.500 mg/L.试验结果表明:厌氧环境(DO<0.5 mg/L)、强还原环境(Eh<-108 mV)、酸性环境(pH<6.0)及温度升高均有利于底泥中NH4+-N的释放,NO3--N的迁移转化规律则相反;供试样控制疏浚深度5 cm、10 cm、15 cm、20 cm,当疏浚深度15 cm时,泥-水界面向上覆水体中扩散的氮通量最小;疏浚深度、DO和Eh对底泥NH4+-N释放程度的影响大于pH和温度,通过曝气等方式保持水体中适当的溶解氧或使底泥保持较强的氧化电位环境可以有效抑制底泥中NH4+-N的释放.Abstract: Water and sediment samples were collected from a polluted river in the old town of Suzhou City.The water in the river is classified as poor quality V according to the National Surface Water Quality Standard of China.We examine the regularity of nitrogen release from sediments under different environmental conditions such as the dissolved oxygen(DO) level,the redox potential status measured as Eh level,the pH value,the temperature,and the dredging depth,using the indoor experimental method.The results show that the contents of ammonia-nitrogen and nitrate materials in sediment samples are 277.03 mg/kg and 1.22 mg/kg,respectively,and these contents are 6.743 mg/L and 1.500 mg/L in the overlying water.The experiments reveal that the favorable conditions for the ammonia-nitrogen release from sediments include the anaerobic environment of DO < 0.5 mg/L,the strong reducing environment of Eh <-108 mV,and the acidic environment of pH < 6.0,as well as the high temperatures; while the opposite behaviors in these conditions are observed for the migration and transformation of NO3--N.The analysis of sediment samples collected at different dredging depths of 5 cm,10 cm,15 cm,and 20 cm indicates that the minimum release of nitrogen nutrient is found from the sample of 15 cm depth.The effects of dredging depth,DO,and Eh on the ammonia-nitrogen release in sediments are found to be greater than that of pH and temperatures.Our experimental study show that the ammonia-nitrogen release from sediments will be effectively inhibited if high dissolved oxygen levels in the overlying water as well as strong oxidizing potential status in the sediment can be properly maintained.
-
Key words:
- sediments /
- release of nitride /
- environmental condition /
- main control factors
-
[1] 刘德启,李敏,朱成文,等.模拟太湖底泥疏浚对氮磷营养物释放过程的影响研究[J].农业环境科学学报,2005,24(3):521-525.(LIU De-qi,LI Min,ZHU Cheng-wen,et al.Effects of simulating sediment-dredging on the release of N and P nutrients in Taihu Lake's sediment[J].Journal of Agro-Environment Science,2005,24(3):521-525.(in Chinese)) [2] 蒋小欣,阮晓红,邢雅囡,等.城市重污染河道上覆水氮营养盐浓度及DO水平对底质氮释放的影响[J].环境科学,2007,28(1):87-91.(JIANG Xiao-xin,RUAN Xiao-hong,XING Ya-nan,et al.Effects of nutrient concentration and DO status of heavily polluted urban stream water on nitrogen release from sediment[J].Environmental Science,2007,28(1):87-91.(in Chinese)) [3] 冯海艳,李文霞,杨忠芳,等.上覆水溶解氧水平对苏州城市河道底泥吸附/释放磷影响的研究[J].地学前缘.2008,15(5):227-233.(FENG Hai-yan,LI Wen-xia,YANG Zhong-fang,et al.Influence of dissolved oxygen in overlying water on releasing/absorption of phosphorus from sediments from Suzhou River[J].Earth Science Frontiers,2008,15(5):227-233.(in Chinese)) [4] 国家环境保护总局水和废水监测分析方法编委会.水和废水监测分析方法[M].四版.北京:中国环境科学出版社,2002:236-284.(Country environmental protection bureau water and waste water monitor analysis method editorial committee.Water and waste water monitor analysis method[M].The fourth edition.Beijing:China Environmental Science Press,2002:236-284.(in Chinese)) [5] 范成新,张路,包先明,等.太湖沉积物-水界面生源要素迁移机制及定量化:Ⅱ磷释放的热力学机制及源汇转换[J].湖泊科学,2006,18(3):207-217.(FAN Cheng-xin,ZHANG Lu,BAO Xian-ming,et al.Migration mechanism of biogenic elements and their quantification on the sediment-water interface of Lake Taihu:Ⅱ Chemical thermodynamic mechanism of phosphorus release and its source-sink transition[J].Journal of Lake Science,2006,18(3):207-217.(in Chinese)) [6] D'ANGELO E M,REDDY K R.Digenesis of organic matter in a wetland receiving hypereutrophic lake water:I Distribution of dissolved nutrients in the soil and water column[J].J Environ Qual,1994,23:928-936. [7] 王晓蓉,华兆哲,徐菱,等.环境变化对太湖沉积物磷释放的影响[J].环境化学,1996,15(1):15-19.(WANG Xiao-rong,HUA Zhao-zhe,XU Ling,et al.The effects of the environment conditions on phosphorus release in lake sediments[J].Environmental Chemistry,1996,15(1):15-19.(in Chinese)) [8] 王静,吴丰昌,黎文,等.云贵高原湖泊颗粒有机物稳定氮同位素的季节和剖面变化特征[J].湖泊科学,2008,20(5):571-578.(WANG Jing,WU Feng-chang,LI Wen,et al.Seasonal variation and vertical characteristics of the δ15N of particulate organic matter in Lake Hongfeng and Lake Baihua,Guizhou province[J].Journal of Lake Sciences.2008,20(5):571-578.(in Chinese)) -
点击查看大图
计量
- 文章访问数: 61
- HTML全文浏览量: 9
- PDF下载量: 554
- 被引次数: 0
下载:
