Published reports suggest efforts designed to prevent the occurrence of harmful algal blooms and hypoxia by reducing non‐point and point source phosphorus (P) pollution are not delivering water quality improvements in many areas. Part of the uncertainty in evaluating watershed responses to management practices is the lack of standardized estimates of phosphorus inputs and outputs. To assess P trends across the conterminous United States, we compiled an inventory using publicly available datasets of agricultural P fluxes, atmospheric P deposition, human P demand and waste, and point source discharges for 2002, 2007, and 2012 at the scale of the 8‐digit Hydrologic Unit Code subbasin (∼1,800 km²). Estimates of agricultural legacy P surplus accumulated from 1945 to 2001 were also developed. Fertilizer and manure inputs were found to exceed crop removal rates by up to 50% in many agricultural regions. This excess in inputs has led to the continued accumulation of legacy P in agricultural lands. Atmospheric P deposition increased throughout the Rockies, potentially contributing to reported increases in surface water P concentrations in undisturbed watersheds. In some urban areas, P fluxes associated with human waste and non‐farm fertilizer use has declined despite population growth, likely due, in part, to various sales bans on P‐containing detergents and fertilizers. Although regions and individual subbasins have different contemporary and legacy P sources, a standardized method of accounting for large and small fluxes and ready to use inventory numbers provide essential infromation to coordinate targeted interventions to reduce P concentrations in the nation's waters.

中文翻译：

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美国本土磷库存（2002-2012 年）

已发表的报告表明，旨在通过减少非点源和点源磷 (P) 污染来防止有害藻华和缺氧发生的努力并未在许多地区带来水质改善。评估流域对管理实践的反应的部分不确定性是缺乏对磷输入和输出的标准化估计。为了评估整个美国本土的磷趋势，我们使用 2002 年、2007 年和 2012 年农业磷通量、大气磷沉降、人类磷需求和浪费以及点源排放的公开数据集编制了一份清单，规模为 8 ‐数字水文单元代码子流域 (∼1,800 km ²). 还对 1945 年至 2001 年积累的农业遗留 P 盈余进行了估算。在许多农业地区，化肥和粪肥输入量超过作物去除率高达 50%。这种投入过剩导致农田遗留磷的持续积累。整个落基山脉的大气磷沉积增加，可能导致未受干扰流域地表水磷浓度增加的报道。在一些城市地区，尽管人口增长，但与人类排泄物和非农化肥使用相关的磷通量有所下降，这可能部分是由于对含磷洗涤剂和化肥的各种销售禁令。尽管区域和各个子流域具有不同的现代和遗留磷源，