【摘要】 反硝化作用是地下水硝酸盐污染去除最重要的过程。为研究含水层中反硝化作用强度及其影响因素,采用整合分析法对不同含水介质类型中的反硝化强度范围进行了总结,揭示了反硝化强度在含水层中垂向分布规律,研究了不同取样深度和不同溶解氧（DO）浓度下的反硝化强度影响因素,分析了反硝化强度统计结果的不确定性。结果表明,大多含水介质中反硝化强度处于10^-1～10²μg·kg^-1·d^-1,砂和砂砾石含水介质中可以达到10³μg·kg^-1·d^-1量级。含水介质粒间孔隙大小与反硝化强度未呈明显相关关系。反硝化强度沿含水层垂向上先逐渐增大后显著减小,在某深度处存在峰值,峰值对应的深度存在明显的区域差异。浅层含水层反硝化强度主要受有机碳浓度影响;深层含水层反硝化强度主要受Eh值影响。当DO浓度为0.2～2 mg·L^-1时,反硝化强度与取样深度、地下水位埋深、NO₃^--N浓度和Eh均呈不显著负相关关系;DO浓度介于2～6 mg·L^-1时,与取样深度呈显著负相关,与温度为显著正相关;DO浓度大于6 mg·L^-1时,与Eh呈显著负相关关系。反硝化强度测定、计算方法的不同和统计过程导致统计结果具有一定的不确定性。更多还原

【Abstract】 An understanding of the denitrification process of nitrate in groundwater is vital because it can dissipate groundwater nitrate pollution.In this study,in order to the determine the intensity and factors affecting denitrification in aquifers,an integrated analysis method was adopted to summarize the ranges in denitrification intensities in different aquifer mediums.Then,the vertical distribution of denitrification intensities was revealed along the sampling depth.Finally,the factors affecting denitrification intensity were determined in the different grades of sampling depths and DO concentrations.Additionally,the uncertainty of the statistical results of denitrification intensities was analyzed.The results showed that the denitrification intensities of nitrate in the groundwater generally ranged between 10^-1～10²μg·kg^-1·d^-1,and could reach 10³μg·kg^-1·d^-1in the sand and gravel mediums.No significant correlation between the pore size and denitrification intensity was found.The denitrification intensities increased gradually and then decreased significantly along the sampling depth from the ground surface.The distinction of the depths that corresponded to the peak value of denitrification intensity was significant at different sites.The denitrification intensities in the shallow and deep aquifers were affected by organic carbon and Eh,respectively.When the DO concentrations ranged between 0.2～2.0 mg·L^-1,the denitrification intensity had a non-significant negative relationship with the sampling depth,groundwater depth,NO₃^--N concentration,and Eh.When the DO concentration ranged between 2～6 mg·L^-1,it was negatively correlated with sampling depth and positively correlated with temperature.When the DO concentration was greater than 6 mg·L^-1,it was negatively correlated with Eh.The uncertainty of the statistical results of denitrification intensity mainly resulted from the experimental methods,calculation methods,and statistical processes.Our results could supply a theoretical basis for the fate of nitrate in aquifers and for the prevention,control,and restoration of groundwater nitrate pollution.更多还原