Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, China.
Hebei Key Laboratory of Groundwater Remediation, Shijiazhuang, China.
Environ Sci Pollut Res Int. 2022 Mar;29(12):17031-17048. doi: 10.1007/s11356-021-17067-4. Epub 2021 Oct 16.
High concentration of nitrate (NO) in groundwater is a major concern because of its complex origin and harmful effects on human health. This study aims to investigate the distributions of nitrate in various aquifers and in areas with different land use types in alluvial-pluvial fans in North China Plain, to identify dominant sources and factors using hydrochemical data and principal component analysis, and to conduct health-risk assessment of groundwater nitrate using the models recommended by USEPA. Results show that approximately 76.1% groundwater in fissured aquifers showed high-NO (> 50 mg/L), and was 2.7 times of that in granular aquifers. In fissured aquifers, the proportion of high-NO groundwater (PHNG-WHO) in peri-urban areas was more than 1.3 times of those in other areas. Similarly, in shallow granular aquifers, the PHNG-WHO in peri-urban areas was also higher than that in other areas. By contrast, in deep granular aquifers, the PHNG-WHO in urbanized areas was 2.8 and 5.2 times of that in peri-urban areas and farmland, respectively. High NO levels in both granular and fissured aquifers originated mainly from domestic sewage and animal waste, and fertilizers are also important sources of NO in fissured aquifers. Intensive groundwater exploitation aggravated nitrate contamination because more thickness of vadose zones resulting from over-exploitation is in favor of nitrification. Risk assessment of groundwater nitrate indicated about 43.3%, 45.6%, and 54.2% of the groundwater samples showed unacceptable non-carcinogenic risk to adult males, adult females, and children, respectively. The proportion of samples with health risks had a significant positive correlation with the urbanization level. Our study indicates that several effective measures for pollution prevention, such as strengthening sewage treatment and prohibiting groundwater over-exploitation, must be adopted so as to ensure the sustainable management of groundwater and the safety of drinking water.
地下水硝酸盐浓度高是一个主要问题，因为其来源复杂，对人类健康有害。本研究旨在调查华北平原冲积扇不同含水层和不同土地利用类型区硝酸盐的分布，利用水化学数据和主成分分析确定主要来源和因素，并采用美国环保署推荐的模型对地下水硝酸盐进行健康风险评估。结果表明，裂隙含水层中约 76.1%的地下水硝酸盐含量较高（>50mg/L），是颗粒含水层的 2.7 倍。在裂隙含水层中，城市周边地区高硝酸盐地下水（PHNG-WHO）的比例高于其他地区的 1.3 倍以上。同样，在浅层颗粒含水层中，城市周边地区的 PHNG-WHO 也高于其他地区。相比之下，在深层颗粒含水层中，城市化地区的 PHNG-WHO 分别是城市周边地区和农田地区的 2.8 倍和 5.2 倍。颗粒含水层和裂隙含水层中硝酸盐含量高主要来源于生活污水和动物粪便，化肥也是裂隙含水层中硝酸盐的重要来源。地下水开采的集约化加剧了硝酸盐污染，因为过度开采导致的更多厚度的包气带有利于硝化作用。地下水硝酸盐风险评估表明，约 43.3%、45.6%和 54.2%的地下水样本对成年男性、成年女性和儿童分别表现出不可接受的非致癌风险。具有健康风险的样本比例与城市化水平呈显著正相关。本研究表明，必须采取加强污水处理和禁止地下水过度开采等有效污染防治措施，以确保地下水的可持续管理和饮用水安全。
