江汉平原典型地区季节性水文条件影响下氮的动态变化规律
发布时间：2018-07-23 11:35
【摘要】：江汉平原东部地区地下水硝态氮和氨氮污染严重,地表水-地下水相互作用强烈,季节性水文条件变化极其显著.选取典型试验场地,对试验场内沉积物(025m)氮形态进行测定,并对地下水氮含量及其他水化学指标进行连续性监测.研究表明:沉积物NO_3~--N含量较高(25.8119.48mg/kg),是可交换态氮的主要组成部分,NH_3_-N含量与TOC和TN均呈一定的正相关性,表明NH_3-N含量主要受沉积物中埋藏有机质的控制.试验场深度较深(≥2m)地下水氮的含量和形态对地下水位波动有明显响应:雨季开始,地下水位抬升,含水介质还原性增强,NO_3~--N生成受抑制且通过反应消耗,矿化作用加强,导致NH_3-N成为氮的主要赋存形态;雨季结束,地下水水位下降,含水介质的氧化性增强,NO_3~--N的生成受到促进,硝化作用增强而反硝化作用减弱,导致NO_3~--N的浓度增加.近地表人类活动(外源输入)对试验场浅表地层(2m)地下水氮形态有明显的影响.自然或者人为因素引起的水文条件变化导致地下水流场的变化,从而改变含水介质固有的氧化还原环境,是导致试验场氮季节性变化的主要原因.
[Abstract]:In the eastern part of Jianghan Plain, the pollution of nitrate nitrogen and ammonia nitrogen in groundwater is serious, the interaction between surface water and groundwater is very strong, and the seasonal hydrological conditions change remarkably. The nitrogen forms of sediment (0.25 m) in the test site were determined, and the nitrogen content of groundwater and other hydrochemical indexes were continuously monitored. The results show that the content of NO_3~--N (25.8119.48mg/kg) is high in sediment, and it is the main component of exchangeable nitrogen. The content of NH3- N in the sediment is positively correlated with TOC and TN, indicating that the content of NH_3-N is mainly controlled by buried organic matter in sediment. The nitrogen content and form of groundwater in deeper depth (鈮，
本文编号：2139287
[Abstract]:In the eastern part of Jianghan Plain, the pollution of nitrate nitrogen and ammonia nitrogen in groundwater is serious, the interaction between surface water and groundwater is very strong, and the seasonal hydrological conditions change remarkably. The nitrogen forms of sediment (0.25 m) in the test site were determined, and the nitrogen content of groundwater and other hydrochemical indexes were continuously monitored. The results show that the content of NO_3~--N (25.8119.48mg/kg) is high in sediment, and it is the main component of exchangeable nitrogen. The content of NH3- N in the sediment is positively correlated with TOC and TN, indicating that the content of NH_3-N is mainly controlled by buried organic matter in sediment. The nitrogen content and form of groundwater in deeper depth (鈮，
本文编号：2139287
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