Impact of groundwater nitrogen legacy on water quality

作者：Xiaochen Liu, Arthur Beusen, Hans J. M. van Grinsven, Junjie Wang, Wim Joost van Hoek, Xiangbin Ran, José M. Mogollón, Lex Bouwman · 发表于：Nature Sustainability · 年份：2024 · DOI：10.1038/s41893-024-01369-9 · 被引用次数：136 · 研究领域：Soil and Water Nutrient Dynamics、Hydrology and Watershed Management Studies、Groundwater and Isotope Geochemistry

Abstract The loss of agricultural nitrogen (N) is a leading cause of global eutrophication and freshwater and coastal hypoxia. Despite regulatory efforts, such as the European Union’s Nitrogen Directive, high concentrations of N persist in freshwaters. Excessive N leaching and accumulation in groundwater has created a substantial N reservoir as groundwater travel times are orders-of-magnitude slower than those of surface waters. In this study we reconstructed past and projected future N dynamics in groundwater for four major river basins, the Rhine, Mississippi, Yangtze and Pearl, showcasing different N trajectories. The Rhine and Mississippi river basins have accumulated N since the 1950s and although strategies to reduce excess agricultural N have worked well in the Rhine, groundwater legacy N persists in the Mississippi. The Yangtze and Pearl river basins entered the N accumulation phase in the 1970s and the accumulation is expected to continue until 2050. Policies to reduce N pollution from fertilizers have not halted N accumulation, highlighting the importance of accounting for the N legacy in groundwater. Restoring groundwater N storage to 1970 levels by diminishing N leaching will therefore take longer in the Yangtze and Pearl (>35 years) than in the Rhine (9 years) and Mississippi (15 years). Sustainable watershed management requires long-term strategies that address the impacts of legacy N and promote sustainable agricultural practices aligned with the Sustainable...