新疆喀什地区东部地下水“三氮”空间分布特征及影响因素

Spatial distribution and influencing factors of “Three-Nitrogen” in Groundwater of the eastern area of Kashgar,Xinjiang

本文对新疆喀什地区东部地下水"三氮"空间分布特征及影响因素进行了研究.结果表明,该地区地下水"三氮"含量总体较低;NO_3-N含量范围为ND(未检出)—8.02 mg·L^(-1)、样点均值1.17 mg·L^(-1);NO_2-N含量范围为ND(未检出)—0.15 mg·L^(-1)、样点均值0.006 mg·L^(-1);NH_4-N含量范围为ND(未检出)—至0.28 mg·L^(-1)、样点均值0.04 mg·L^(-1);仅个别监测井NO_2-N和NH_4-N含量超标.水平分布特征表现为:NO_3-N含量总体呈南高北低,NO_2-N和NH_4-N含量总体呈南低北高.垂向分布特征表现为:潜水中NO_3-N含量(均值3.14 mg·L^(-1))高于浅层承压水(均值0.50 mg·L^(-1))和深层承压水(均值1.28 mg·L^(-1)),浅层承压水中NO_2-N(均值0.008 mg·L^(-1))和NH_4-N含量(均值0.05 mg·L^(-1))高于深层承压水(NO_2-N均值0.002 mg·L^(-1);NH_4-N均值0.02 mg·L^(-1))和潜水(NO_2-N均值0.001 mg·L^(-1);NH_4-N未检出);NO_2-N和NH_4-N超标点全部集中在浅层承压水中.该地区地下水"三氮"迁移和转化主要受氧化还原条件、地表水水质、包气带岩性、地下水径流条件、潜水埋深、土地利用类型和生活污染等因素的影响.

This paper investigated the spatial variation and influence factors of ＂Three-Nitrogen＂in groundwater in the eastern area of Kashgar,Xinjiang. The results showed that the concentrations of＂Three-Nitrogen＂were comparatively low in the groundwater. The concentrations of NO_3-N were less than 8.02 mg·L^（-1）（average of 1.17 mg·L^（-1））,NO_2-N were less than 0. 152 mg·L^（-1）（average of0.006 mg·L^（-1））,and NH_4-N were less than 0. 28 mg·L^（-1）（average of 0. 04 mg·L^（-1））. The concentrations of NO_2-N and NH_4-N were over the standard only in a few monitoring wells.Horizontally,the concentrations of NO_3-N in the south of the study area were greater than those in the north,while the concentrations of NO_2-N and NH_4-N in the north were greater than those in thesouth. Vertically,the average concentrations of NO_3-N in phreatic water（3.14 mg·L^（-1）） were greater than those of shallow confined water（0.50 mg·L^（-1）） and deep confined water（1.28 mg·L^（-1））,while the average concentrations of NO_2-N（0. 008 mg·L^（-1）） and NH_4-N（0. 05 mg·L^（-1）） in shallow confined water were greater than those of deep confined water（NO_2-N of 0.002 mg·L^（-1）and NH_4-N of 0.02 mg·L^（-1）） and phreatic water（NO_2-N of 0. 001 mg·L^（-1）and NH_4-N under detection limit）.The samples with over the standard concentrations of NO_2-N and NH_4-N were only distributed in shallow confined water. Redox conditions,surface water quality,lithology of vadose zone,run off conditions of groundwater,buried depth of groundwater,land use types and domestic pollution all had impacts on the distribution and transformation of ＂Three-Nitrogen＂in groundwater in the study area.