Abstract. Contaminant inputs to soil are highly dependent on anthropogenic activities, while contaminant retention, mobility, and availability are highly dependent on soil properties. The knowledge of partitioning between soil solid and solution phases is necessary to estimate whether deposited amounts of contaminants will be either transported with runoff or accumulated. Besides, runoff is expected to change during the next century due to changes in climate and in rainfall patterns. In this study, we aimed to estimate at the European scale the areas with a potential risk due to contaminant leaching (LP). We also defined, in the same way, the surface areas where limited copper (Cu) leaching occurred, leading to potential accumulation (AP) areas. We focused on Cu widely used in agriculture either in a mineral form or in association with organic fertilizers, resulting in high spatial variations in the deposited and incorporated amounts in soils, as well as in European policies of application. We developed a method using both Cu partition coefficients (Kf) between total and dissolved Cu forms and runoff simulation results for historical and future climates. The calculation of Kf with pedo-transfer functions allowed us to avoid any uncertainties due to past management or future depositions that may affect total Cu concentrations. Areas with a high potential risk of leaching or of accumulation were estimated over the 21st century by comparing Kf and runoff to their respective European medians. Thus, at three distinct times, we considered a grid cell to be at risk of LP if its Kf was low compared to the European median and if its runoff was high compared to the European median of the time. Similarly, a grid cell was considered to be at risk of AP if its Kf was high and its runoff was low compared to its respective European median of the time. To deal with uncertainties in climate change scenarios and the associated model prediction, we performed our study with two atmospheric greenhouse gas representative concentration pathways (RCPs), defined according to climate change associated with a large set of socio-economic scenarios found in the literature. We used two land surface models (ORCHIDEE and LPJmL, given soil hydrologic properties) and two global circulation models (ESM2m and CM5a, given rainfall forecasts). Our results show that, for historical scenarios, 6.4 ± 0.1 % (median, median deviation) and 6.7 ± 1.1 % of the grid cells of the European land surfaces experience LP and AP, respectively. Interestingly, we simulate a constant surface area with LP and AP for around 13 % of the grid cells, which is consistent with an increase in AP and a decrease in LP. Despite large variations in LP and AP extents, depending on the land surface model used for estimations, the two trends were more pronounced with RCP 6.0 than with RCP 2.6, highlighting the global risk of combined climate change and contamination and the need for more local and seasonal assessments. Results are discussed to highlight the points requiring improvement to refine predictions.

中文翻译：

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气候变化情景下土壤金属积累或淋滤潜力的估算：以欧洲范围内的铜为例


摘要。土壤污染物的输入高度依赖于人类活动，而污染物的滞留、迁移性和可用性高度依赖于土壤特性。了解土壤固相和溶液相之间的分配对于估计沉积的污染物量是否会随径流迁移或积累是必要的。此外，由于气候和降雨模式的变化，预计径流在下个世纪将会发生变化。在这项研究中，我们的目的是在欧洲范围内估计因污染物浸出（LP）而存在潜在风险的地区。我们还以同样的方式定义了发生有限铜 (Cu) 浸出的表面区域，从而导致潜在积累 (AP) 区域。我们关注的是铜在农业中以矿物形式或与有机肥料结合广泛使用，导致土壤中沉积和掺入量以及欧洲应用政策的巨大空间变化。我们开发了一种方法，使用总铜和溶解铜形式之间的铜分配系数 (Kf) 以及历史和未来气候的径流模拟结果。使用pedo-transfer函数计算Kf使我们能够避免由于过去的管理或未来的沉积而可能影响总铜浓度的任何不确定性。通过将 Kf 和径流与各自的欧洲中位数进行比较，估算了 21 世纪具有较高潜在淋滤或积累风险的地区。因此，在三个不同的时间，如果网格单元的 Kf 与欧洲中位数相比较低，并且其径流与当时的欧洲中位数相比较高，我们认为网格单元存在 LP 风险。 同样，如果与相应的欧洲时间中位数相比，网格单元的 Kf 高并且其径流量低，则该网格单元被认为处于 AP 风险中。为了应对气候变化情景和相关模型预测的不确定性，我们使用两种大气温室气体代表性浓度路径（RCP）进行了研究，这两种路径是根据文献中与大量社会经济情景相关的气候变化定义的。我们使用了两个陆地表面模型（ORCHIDEE 和 LPJmL，给定土壤水文特性）和两个全球环流模型（ESM2m 和 CM5a，给定降雨预报）。我们的结果表明，对于历史情景，欧洲陆地表面的网格单元分别有 6.4±0.1%（中值、中值偏差）和 6.7±1.1% 经历过 LP 和 AP。有趣的是，我们用 LP 和 AP 模拟了大约 13% 的网格单元的恒定表面积，这与 AP 的增加和 LP 的减少一致。尽管 LP 和 AP 范围存在很大差异，但根据用于估算的地表模型，RCP 6.0 的这两种趋势比 RCP 2.6 更为明显，突显了气候变化和污染相结合的全球风险，以及需要更多的本地和季节性评估。对结果进行讨论以突出需要改进的点以完善预测。