皂河-渭河交汇区三氮的行为特征分析

关注特定地质地貌控制下河流交互带氮素空间分布特征及污染状况，有助于全面了解河流水环境特征及污染成因。以皂河与渭河交汇处为研究区，分别沿河流方向、垂向、横向设置采样点，研究了交互区地表水、地下水和沉积物中三氮分布变化特征及其与生物地球化学的关系。结果表明:1）沿河流流向，皂河NO₃--N的浓度低于渭河，两河交汇之后NO₃--N浓度逐渐增大与渭河浓度水平一致，而地下水中其浓度逐渐减小。地表水和地下水中NO₂--N和NH₄+-N均有沿河流流向浓度逐渐减小的趋势。横向剖面上，NO₃--N分布明显受河流地下水补给方式影响。2）从空间上看，NO₃--N随着深度增大，表现出先增大后减小的分布规律。而NH₄+-N随着深度增大先降低然后又有增加趋势。3）水体中pH与NO₃--N极显著正相关，DO与NH₄+-N显著负相关。沉积物中TOC与NO₂--N表现出显著负相关。三氮之间NO₂--N与NH₄+-N表现出极显著正相关。

BEHAVIORAL CHARACTERISTICS OF NITROGEN IN THE ZAOHE AND WEIHE RIVER INTERSECTION

Focusing on the spatial distribution characteristics and pollution of nitrogen in the interaction zone of rivers under specific geological and geomorphological control, it is helpful to fully understand the characteristics of river water environment and the causes of pollution. In this paper, the intersection of Zaohe River and Weihe River was taken as the research area, and sampling points were set along the river direction, vertical and horizontal, respectively. The variation characteristics of the distribution of nitrogen in surface water, groundwater and sediments in the interaction zone and their biogeochemistry properties were studied. The results showed that:1) along the river, the concentration of NO₃--N in the Zaohe River was lower than that in the Weihe River. The concentration of NO₃--N increases after the intersection of the two rivers, while the concentration in the groundwater gradually decreased. Both NO₂--N and NH₄+-N in surface water and groundwater had a tendency to gradually decrease in river flow direction. In the transverse section, the NO₃--N distribution was obviously affected by the groundwater recharge mode of the river. 2) By the space, NO₃--N increased with depth, showing a distribution law of increasing first and then decreasing. The NH₄+-N began to decrease with depth and then increased. 3) The pH of water was significantly positively correlated with NO₃--N, and DO was significantly negatively correlated with NH₄+-N. TOC in the sediment showed a significant negative correlation with NO₂--N. There was a very significant positive correlation between NO₂--N and NH₄+-N between the nitrogen.