黄河下游引黄灌区硝酸盐来源与地下水年龄示踪

Sources of nitrate (NO3-), influence factors on the nitrate migration behavior and groundwater ages are the key scientific issues for the field of eco-hydrology and water environment. To select the Panzhuang Irrigation Districts in the Lower Yellow River, samples were taken at the expected sites in the precipitation (dry and wet deposition), surface water (main waters in study area and irrigation water from the Yellow River), soil water (water in each layer in the fixed sites) and groundwater (hydrology geological observation wells in Yucheng). Water quality characteristics, major ions, Fe, Mn, organic carbon, Br-, stable isotopes 2H and 18O, 15N and 18O in NO3- will be analyzed. At the same time, the regional potential sources of NO3 such as fertilizers, septic tanks, manure, domestic and industrial waste water will be analyzed with 15N and18O isotopic composition. Quantify the source of groundwater NO3- based on hydrological processes and water quality evolution, revealing the surface water - soil - groundwater exchange behavior and mechanism of the nitrate migration and transformation. Meanwhile, according to the positioning observation and hydrogeological conditions, swat model will be used to quantify and evaluate the impact on the region of NO3-flux, which provide a scientific basis for the effect of nitrate evaluation of irrigation on regional surface water and groundwater.

硝酸盐（NO3-）的来源、空间上的运移行为与影响因素、时间上何时进入地下水等问题是生态水文与水环境领域的关键科学问题。本项目拟在黄河下游引黄灌区选取潘庄灌区为例，通过对区域内定点监测降水（包括干湿沉降）-地表水（区域内主要水体和引黄灌溉水）-土壤水（地表至地下水位间的定位观测与采样）和地下水（禹城站和水文地质观测井），分析水质特征、主要阴阳离子、影响NO3-转换过程的Fe、Mn和有机碳、稳定同位素2H和18O、NO3-中的15N和18O、Br-，同时，对区域内潜在来源如化肥、化粪池、畜禽粪便和生活和工业污水等进行NO3-的15N和18O分析，根据水文过程与水质演化量化地下水中NO3-的来源与比例，揭示地表水-土壤水-地下水交换过程中硝酸盐的行为与机理，根据定位观测与水文地质条件用模型量化与评价引黄灌溉对区域NO3-通量的影响，为评价灌溉对区域地表水和地下水硝酸盐的影响提供科学依据。

硝酸盐（NO3-）的来源、空间上的运移行为与影响因素及其对地表、地下水污染等问题是生态水文与水环境领域的关键科学问题，本研究以黄河下游第二大罐区－潘庄罐区（36.4°～38.0° N、115.75°～117.6° E）为研究对象，范围涉及齐河、禹城、夏津、武成、平原、陵县、德城、宁津8个县市。研究内容包括区域水体(降水-地表水-地下水)样品采集与分析、区域硝酸盐潜在来源调查和微区实验三大部分。在区域上，依据区域水文地质条件，共采集47个地表水样品（包括16个引黄水与31个当地河水）和40个地下水样品等多种NO3-潜在污染源样品。借助水化学和多种环境同位素（δD and δ18O）技术来判定地表水和地下水的关系；揭示硝酸盐了硝酸盐的时空分布规律；追溯NO3-的来源及量化其比例；在微区实验上，研究选择中国科学院禹城综合试验站作为典型点，通过15N标记微区控制实验阐述NO3-垂直迁移转化机理。目前已发表SCI论文11篇，EI论文2篇，CSCD论文1篇，圆满完成了计划内容。