密云水库流域地下水硝态氮的分布及其影响因素  

NITRATE CONCENTRATION DISTRIBUTION IN GROUNDWATER OF THE MIYUN RESERVOIR WATERSHED

作　　者：王庆锁[1] 孙东宝[1] 郝卫平[1] 顾颖[1] 李玉中[1] 梅旭荣[1] 张燕卿[1] 

机构地区：[1]中国农业科学院农业环境与可持续发展研究所,农业部旱作节水农业重点开放实验室,北京100081

出　　处：《土壤学报》2011年第1期141-150,共10页Acta Pedologica Sinica

基　　金：国家科技支撑计划项目“沿湖地区农业面源污染阻控关键技术研究”(课题编号:2007BAD87B01),国家科技重大专项“华北村镇地下饮用水安全保障技术研究与示范”(课题编号:2008ZX07425)共同资助;北京市科技计划项目(编号:D0705045040391)

摘　　要：2008年11月至12月,采集了密云水库流域305个井的地下水样品,分析了其硝态氮含量。结果表明,密云水库流域地下水的硝态氮含量的平均值、超标率(10 mg L-1≤NO3--N<20 mg L-1)和严重超标率(NO3--N≥20 mg L-1)分别为6.81 mg L-1、13.77%和2.30%。其中村庄和菜地的地下水硝酸盐污染最为严重,35个村庄井和13个菜地井的地下水硝态氮含量的平均值分别为9.52 mg L-1和9.55 mg L-1,已接近WHO饮用水硝态氮含量10 mg L-1的限定标准,超标率分别为20%和15.38%,严重超标率分别为8.57%和7.69%。219个粮田井水的硝态氮水平位居中间,其硝态氮含量的平均值、超标率和严重超标率分别为6.59mg L-1、14.61%和1.37%。10个林地井的地下水硝态氮含量是最低的,其平均值为2.66 mg L-1,无超标现象。潮河流域农田地下水的硝酸盐污染比白河流域严重。潮河流域农田(124个井)的地下水硝态氮含量的平均值、超标率和严重超标率分别为8.42 mg L-1、21.77%和3.23%,而白河流域(122个井)则分别为5.03mg L-1、6.56%和0,即无严重超标现象。密云水库流域农田地下水的硝态氮含量呈现出上游低而下游高的趋势。玉米田地下水硝态氮含量在接近河道的地方有所降低,与地下水水位呈负相关,与化肥氮的施用量呈正相关,当地下水位小于7m时或当一年的化肥氮的施用量超过200 kg hm-2,存在地下水硝态氮含量超标的潜在危险。Water samples were collected from 305 wells in the Miyun Reservoir Watershed during the period from November to December, 2008, for analysis of nitrate nitrogen （NO3- -N） concentrations. It was found that NO3 -N concentrations of the samples averaged 6. 81 mg L-1 ; samples from 13.77% of the wells exceeded 10 mg L-1, the WHO limit for NO3- -N in drinking water, and from 2.3% of the wells did 20 mg L-1 , the criterion for serious NO3--N pollution. Nitrate pollution was the most serious in groundwater under villages and vegetable fields. NO3--N concentrations of the samples from 35 wells in villages and 13 wells in vegetable fields averaged 9.52 mg L-1 and 9.55 mg L-1 , respectively, very close to the WHO limit for drinking water. About 20% of the wells in village and 15.38% of the wells in vegetable fields were found to have NO3- -N concentrations in groundwaters exceeding 10 mg L-l, but below 20 mg L-i and 8.57% and 7.69% exceeding 20 mg L-1. Nitrate concentrations in 219 wells on croplands （corn and soybean） were moderate, being 6.59 mg L-1 on average. About 14.61% of the wells on cropland were found to have NO3-N concentrations in goundwaters exceeding 10 mg L-1 and 1.37% exceeding 20 mg L-1. NO3--N concentrations in the 10 wells on woodlands were the lowest with an average being 2.66 mg L-1 and none of them were beyond the WHO limit. Nitrate pollution of groundwater was more severe in the Chaohe River Basin than in the Baihe River Basin. Average NO3--N concentration in the groundwater from farm- lands in the Chaohe River Basin reached 8.42 mg L-1, higher than that （5.03 mg L-1 ） in the Baihe River Basin. NO3-N concentrations in 21.77% of the 124 wells on farmlands in the Chaohe River Basin exceeded 10 mg L-1 while only 6.56% of the 122 wells in Baihe River Basin did, and 3.23% of the 124 wells on farmlands in the Chaohe River Basin exceeded 20 mg L-l while none in the Baihe River Basin did. NO3- -N concentration of groundwater in farmlands alongside the rivers increased from upstream to downstream,

关 键 词：硝态氮 地下水 密云水库流域 

分 类 号：X523[环境科学与工程—环境工程]