Mineral phosphate (P) fertilisers are the main suspected sources of uranium (U) and cadmium (Cd) input to agricultural soils. This study was set up to survey the general long-term impact of P fertilisers on concentrations of Cd, U and other trace metals in European soils. A total of 218 soil samples was collected from 15 long-term (3–78 years, median 18 years) P trials at 11 locations with a pairwise comparison of topsoil composition between the fertilised and corresponding unfertilised soils. Aqua regia soil extraction detected the effects of fertilisation more sensitively than the HF (real total) soil extraction. Statistically significant differences in aqua regia soluble metals due to fertiliser application were detected more frequently for U (10 of 15 trials) than for Cd (4 of 15 trials). The concentrations of U and Cd in soil linearly increased with cumulative applied P across all soils and sites; a total addition of 1 ton P ha⁻¹ increased the mean topsoil (23 cm depth) concentrations by 0.11 mg U kg⁻¹ soil (0.09–0.12 mg U kg⁻¹, 95% CI) and 0.03 (0.02–0.04) mg Cd kg⁻¹ soil. These results correspond with mass balance predictions (1 ton P ha⁻¹; +0.15 mg U kg⁻¹ soil and +0.02 mg Cd kg⁻¹ soil) based on previously determined average trace element concentrations in European fertilisers. Data thus suggests that, on average among trials, losses of Cd from soil are undetectable. In contrast, about 30% of the theoretical U input from fertilisers is lost in the same trials. This study provides data to better evaluate the modelled trace metal accumulations in soil and to evaluate the prevailing metal limits in mineral fertilisers.

中文翻译：

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欧洲长期田间试验中矿物磷肥在农业土壤中的微量金属积累

矿物磷酸盐 (P) 肥料是向农业土壤输入的铀 (U) 和镉 (Cd) 的主要可疑来源。本研究旨在调查磷肥对欧洲土壤中 Cd、U 和其他微量金属浓度的一般长期影响。从 11 个地点的 15 个长期（3-78 年，中位数 18 年）磷试验中收集了总共 218 个土壤样品，对施肥土壤和相应未施肥土壤之间的表土成分进行了成对比较。王水土壤提取比 HF（实际总）土壤提取更敏感地检测到施肥的影响。王水的统计显着差异U（15 次试验中的 10 次）比 Cd（15 次试验中的 4 次）更频繁地检测到因施肥而导致的可溶性金属。土壤中 U 和 Cd 的浓度随着所有土壤和地点的累积施用 P 线性增加；总共添加 1 吨 P ha ^-1使平均表土（23 cm 深度）浓度增加 0.11 mg U kg ^-1土壤（0.09–0.12 mg U kg ^-1 , 95% CI）和 0.03 (0.02–0.04) mg Cd kg ^-1土壤。这些结果与质量平衡预测一致（1 吨 P ha ^-1；+0.15 mg U kg ^-1土壤和 +0.02 mg Cd kg ^-1土壤）基于先前确定的欧洲肥料中的平均微量元素浓度。因此，数据表明，在试验中，平均而言，土壤中 Cd 的损失是无法检测到的。相比之下，在相同的试验中，大约 30% 的来自肥料的理论 U 输入损失。本研究提供的数据可以更好地评估土壤中模拟的痕量金属积累，并评估矿物肥料中普遍存在的金属限制。