Abstract. Floodplain soilscapes act as temporary sinks in the environment and are nowadays affected by multiple contaminant accumulations and exposures, including heavy metals and (micro-)plastics. Despite increasing knowledge of the occurrence and behaviour of (micro-)plastics at the interface between aquatic and terrestrial systems, there are still major uncertainties about the spatial distribution of plastics, their sources and deposition, as well as spatial relationships with other contaminants. Our recent case study addresses these questions, using the example of a river system ranging from rural to urban areas. Based on a geospatial sampling approach we obtained data about soil properties, heavy metal contents via ICP-MS analyses, and particle-based (171 µm–52 mm) plastic contents, analysed using sodium chloride density separation, visual fluorescence identification and ATR-FTIR analysis. We found plastic contents of 0.00–35.82 p kg⁻¹ and heavy metal enrichment (Enrichment factor 1.1–5.9). Levels of both contaminations occur in the lower range of known concentrations and show a different spatial distribution along the river course and in the floodplain cross-section. Furthermore, we found that plastic enrichment occurs in the uppermost soil layers, while heavy metal enrichment is located at greater depths, indicating different sources and deposition periods. Finally, direct short to long-term anthropogenic impacts, like floodplain restoration or tillage may affect plastic enrichments, raising questions for future floodplain management.

中文翻译：

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高度耕种和城市化的洪泛区土壤景观中的中塑料和微塑料分布以及与重金属污染的空间联系——来自尼达河（德国）的案例研究

摘要。泛滥平原土壤景观充当环境中的临时汇，如今受到多种污染物积累和暴露的影响，包括重金属和（微）塑料。尽管对水生和陆地系统界面处（微）塑料的发生和行为的了解越来越多，但塑料的空间分布、其来源和沉积以及与其他污染物的空间关系仍存在重大不确定性。我们最近的案例研究以从农村到城市地区的河流系统为例，解决了这些问题。基于地理空间采样方法，我们通过 ICP-MS 分析获得了有关土壤特性、重金属含量和基于颗粒（171 µm–52 mm）塑料含量的数据，使用氯化钠密度分离进行分析，视觉荧光识别和 ATR-FTIR 分析。我们发现塑料含量为 0.00–35.82 p kg^-1和重金属富集（富集因子 1.1-5.9）。两种污染的水平都发生在已知浓度的较低范围内，并且沿河道和洪泛区横截面显示出不同的空间分布。此外，我们发现塑料富集发生在最上层土层，而重金属富集位于更深处，表明不同的来源和沉积时期。最后，直接的短期到长期的人为影响，如洪泛区恢复或耕作，可能会影响塑料富集，从而为未来洪泛区管理提出问题。