Nitrate pollution from agricultural sources is one of the biggest issues facing groundwater management in the European Union (EU). During the last three decades, tens of nitrate vulnerable zones (NVZ) have been designated across the EU, aiming to make the problem more manageable. The Gallocanta Groundwater Body in NE Spain was declared as an NVZ in 1997, and after more than 20 years, significant improvements in water quality were expected to be observed. In the present study, the spatiotemporal trend of nitrate concentration within the Gallocanta NVZ in the last 38 years was assessed, and the effectiveness of the NVZ implementation was tested. Data from the official Ebro Basin Confederation monitoring network from 1980 to 2018 were used, and the results showed an increasing but fluctuating trend in nitrate concentration since 1980. Although a slight improvement was detected after the NVZ designation in 1997, the low rate of improvement would take decades to reach desirable levels in most of the area. The lack of update and control of action programmes, the inappropriate NVZ delimitation, and the influence of natural factors seem to be the reasons for the failure of the nitrate reduction measures. Currently, nitrate pollution and groundwater management are a matter of concern for the EU, so given the recurring problems in water supply in the area and the nonfulfillment of the goal of good quality status, more demanding measures are needed to be implemented in the short term.

来自农业的硝酸盐污染是欧盟（EU）地下水管理面临的最大问题之一。在过去的三十年中，欧盟范围内已指定了数十个硝酸盐脆弱区（NVZ），目的是使该问题更易于管理。西班牙东北部的Gallocanta地下水体于1997年被宣布为NVZ，并且经过20多年的发展，人们有望观察到水质的显着改善。在本研究中，评估了过去38年中Gallocanta NVZ中硝酸盐浓度的时空趋势，并测试了NVZ实施的有效性。使用了1980年至2018年官方埃布罗盆地联合会监测网络的数据，结果显示自1980年以来硝酸盐浓度呈上升但波动的趋势。尽管在1997年指定NVZ后检测到略有改善，但改善的速度很慢，需要数十年才能在大多数区域达到理想水平。缺乏更新和控制行动计划，不适当的NVZ划界以及自然因素的影响似乎是硝酸盐还原措施失败的原因。目前，硝酸盐污染和地下水管理已成为欧盟关注的问题，因此鉴于该地区供水中反复出现的问题以及无法实现良好质量状态的目标，短期内需要采取更多苛刻的措施。缺乏更新和控制行动计划，不适当的NVZ划界以及自然因素的影响似乎是硝酸盐还原措施失败的原因。目前，硝酸盐污染和地下水管理已成为欧盟关注的问题，因此鉴于该地区供水中反复出现的问题以及无法实现良好质量状态的目标，短期内需要采取更多苛刻的措施。缺乏更新和控制行动计划，不适当的NVZ划界以及自然因素的影响似乎是硝酸盐还原措施失败的原因。目前，硝酸盐污染和地下水管理已成为欧盟关注的问题，因此鉴于该地区供水中反复出现的问题以及无法实现良好质量状态的目标，短期内需要采取更多苛刻的措施。