松嫩平原地下水氮污染空间变异性及健康风险评价

为探明松嫩平原地下水污染现状及氮污染影响，利用地统计学软件分析了“三氮”（硝态氮、亚硝态氮和铵态氮）含量的特征，采用 ArcGIS 绘制了地下水硝态氮的变异函数图和空间分布图，并应用健康风险评价模型进行了氮污染对人体的潜在健康风险评价。上述研究表明，该区地下水污染物以“三氮”最为突出，其中硝态氮污染最重，变异系数为1．686，属于强变异，含量分布与二阶球状模型拟合最好，块金值和基底效应分别为2．423和0．575，其含量的空间异质性是结构性因素及随机性因素共同造成的，随机性因素稍强；硝态氮污染高风险区占总面积的88．78％，主要分布在东中部高平原区，这一区域大部分为 III 类水，对人体健康存在较高的风险，应引起关注。

Spatial variability and health risk assessment of nitrogen pollution in groundwater in Songnen Plain

In order to present the pollution distribution and influence of nitrogen in groundwater in Songnen Plain, characteristics of nitrate-nitrogen, nitrite-nitrogen, and ammonium-nitrogen are analyzed by statistics software. Semivariograms graph and spatial distribution maps of groundwater nitrate-nitrogen are described by ArcGIS. Then the risk of groundwater nitrate-nitrogen to human health is evaluated by the model of water environmental health risk assessment. The results show that the nitrate-nitrogen is the most serious pollution in groundwater and has a strong spatial variability (variation coefficient of it is 1.686). The groundwater nitrate-nitrogen fits the second spherical model well and the nugget is 2.423, the substrate effect is 0.575, which implies that nitrate-nitrogen concentration distribution is controlled by structural factors and random factors and the later has a stronger effect. The high risk of nitrate-nitrogen pollution mainly distributes in east and central high plain, which accounts for 88.78% of the total area. It should be paid more attention because the water in this region are mostly third class of water quality and has high risk to human health.