东北海伦地区农村地下饮用水硝态氮污染特征及其影响因素分析

地下水硝态氮污染已成为一个全球性的问题，直接影响到人们的生活用水和身体健康.通过对海伦地区157口农村饮用水井取样分析，探讨了该地区地下水硝态氮污染的时空特征及其影响因素.结果表明，地下水中硝态氮平均含量14.01 mg·L^-1，超标率（≥10.00 mg·L^-1）达到26.11%.地下饮用水硝态氮的污染表现出明显的空间分异特征，在空间上地下水硝态氮污染程度从高到低依次为中部漫川漫岗农业区、东北丘陵漫岗农业区，西南平川漫岗农业区.在此基础上，从水井本身性质和污染物来源两方面分析了地下水硝态氮污染影响因素.在水井本身性质方面，水井管道材料不同导致地下水硝态氮受污染程度不同，其中单节管道水井的污染程度显著低于多节管道，平均浓度分别为5.08、 32.57 mg·L^-1，超标率分布为12.26%、 82.35%；整个地区水井硝态氮污染程度与水井绝对深度无显著关系，但在28个同一取样单元，深水井污染程度显著低于浅水井，其中单节管深井、单节管浅井、多节管深井、多节管浅井的平均浓度分别为1.84、 12.02、 25.14、 45.61 mg·L^-1.分析污染物来源可以发现，污染程度较高的地区多处于氮肥施用量较高、户均家禽牲畜量较多的地区，表明地下水硝态氮污染与化肥施用量以及家禽牲畜排泄量呈一定的正相关关系.

Nitrate Pollution in Groundwater for Drinking and Its Affecting Factors in Hailun, Northeast China

Nitrate pollution in groundwater has become a worldwide problem. It may affect the water quality for daily use and thus the health of people. The temporal and spatial characteristics of nitrate pollution in the groundwater were addressed by sample analysis of the drinkable water from 157 wells in Hailun, Heilongjiang, northeastern China. It was found that the mean value of nitrate concentration in all wells was 14.01 mg·L^-1. Of all the samples, the nitrate concentrations of 26.11% wells exceeded the standard of drinkable water (10.00 mg·L^-1). A significant difference was found on the spatial distribution of nitrate pollution in the study area. The pollution degree in term of nitrate pollution was in the order: the central rolling hills and flooding plain > the northeastern mountain area > the southwest rolling hills and plain. Based on the results, the factors causing the pollution we analyzed from the well properties and pollution sources. As for well properties, the type of the pipe material plays a critical role in the groundwater nitrate pollution. It was found that the wells with seamless pipe have less pollution than those with multiple-sections pipe. The concentrations of seamless pipe wells and multiple ones were respectively 5.08 mg·L^-1 and 32.57 mg·L^-1, 12.26% and 82.35% of these two kinds wells exceeded 10.00 mg·L^-1, the state drinking water standard. In the whole Hailun, there is no statistically relationship between nitrate-N levels of wells and the well depth. However, a statistically lower nitrate-N was observed in the deep wells than that in the shallower ones. The mean values of nitrate concentration of the seamless-pipe deep wells, seamless-pipe shallow wells, multiple-section-pipe deep wells and multiple-section-pipe shallow wells were 1.84, 12.02, 25.14 and 45.61 mg·L^-1. Analysis of pollution source shows that the heavily polluted regions are usually associated with large use of nitrogen fertilizer and household livestock or poultry. This indicates a positive correlation between the nitrate-N pollution of groundwater and the nitrogen fertilizer, household livestock, poultry.