Regional groundwater phosphorus (P) concentrations are rarely reported, and it is important to develop a better understanding of background concentrations in shallow groundwater to help develop strategies to mitigate environmental risks. In this study, results collected from 17 different Iowa-based studies conducted from 2006 to 2019 and a total of 210 discrete locations of water table dissolved phosphate (DPO4 3- ) measurements are summarized (a) to assess the occurrence, range, and statistical distribution of groundwater DPO4 3- concentrations in Iowa and (b) to evaluate statewide patterns of DPO4 3- concentrations related to land use or land cover and landscape position. The DPO4 3- concentrations ranged from 0.02 to 1.56 mg L-1 and averaged 0.15 ± 0.19 mg L-1 with a median value of 0.10 mg L-1 (95% confidence interval of 0.08-0.11 mg L-1 ). Although minor variations were observed among land cover class and landscape position, concentrations exhibited uniformity across the state, likely attesting to the legacy of P from historical agricultural management. Median concentrations are higher than typical water quality criteria used to assess risk to surface water systems, implying that simply discharging groundwater DPO4 3- to streams, rivers, and lakes would be sufficient to cause environmental degradation.

中文翻译：

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爱荷华州浅层地下水中的溶解磷酸盐浓度

区域地下水磷 (P) 浓度很少被报道，重要的是更好地了解浅层地下水中的背景浓度，以帮助制定减轻环境风险的策略。在这项研究中，从 2006 年至 2019 年进行的 17 项基于爱荷华州的不同研究和总共 210 个地下水位溶解磷酸盐 (DPO4 3- ) 测量的离散位置收集的结果进行了总结 (a) 以评估发生率、范围和统计爱荷华州地下水 DPO4 3- 浓度的分布和 (b) 评估全州范围内与土地利用或土地覆盖和景观位置相关的 DPO4 3- 浓度模式。DPO4 3- 浓度范围为 0.02 至 1.56 mg L-1，平均为 0.15 ± 0.19 mg L-1，中值为 0.10 mg L-1（95% 置信区间为 0.08-0.11 mg L-1）。尽管在土地覆盖类别和景观位置之间观察到了微小的变化，但全州的浓度表现出一致性，这可能证明了历史农业管理中磷的遗产。中值浓度高于用于评估地表水系统风险的典型水质标准，这意味着简单地将地下水 DPO4 3- 排放到溪流、河流和湖泊中就足以导致环境退化。