CNRS, EPHE, UMR Environment, Transfers and Interactions in Soils and Water Bodies (METIS), UMR 7619, Sorbonne Université, Tour 56-66, 4 Place Jussieu, 75252, Paris, France.
IRD, CNRS, INRA, Univ Paris Diderot Paris 07, UPEC, UMR 7618, Institute of Ecology and Environmental Sciences, Sorbonne Université, IRD, CNRS, INRA, Univ Paris Diderot Paris 07, UPEC, UMR 7618, Institute of Ecology and Environmental Sciences, F-75252, Paris, France.
Environ Sci Pollut Res Int. 2019 Apr;26(10):9785-9795. doi: 10.1007/s11356-019-04405-w. Epub 2019 Feb 7.
With the actual increasing interest for urban soils, the evaluation of soil contamination by trace elements and the dynamics of this contamination appear mandatory to preserve plant and thereby human health. Street trees and the associated soil placed in pits located nearby roads could represent convenient indicators of urban and vehicle traffic influences on soils and plants. However, data on these soils remain scarce, many studies investigating park soils rather than street tree soils. Furthermore, trace elements could be one of the main factors causing the observed urban tree decline, while practitioners more and more question the possible reuse of these soils after the death of trees as well as tree litter collected in the streets. We evaluated the contamination in anthropogenic trace elements (TE), namely Zn, Pb, and Cd, of street trees (Tilia tomentosa) and their soils distributed all over Paris (France). Street tree soils are imported from rural areas at the plantation of each new tree so that tree age corresponds to the time of residence of the soil within an urban environment allowing the evaluation of temporal trends on TE concentration in soils and trees. The TE concentration revealed an important soil pollution, especially for the older soils (mean age of 80 years old). The consideration of the residence time of trees and soils in an urban environment evidenced an accumulation of Zn and Pb (ca. 4.5 mg kg year and 4 mg kg year for Zn and Pb, respectively). However, leaf concentrations in TE were low and indicate that soil-root transfer was not significant compared to the contamination by atmospheric deposition. These results underlined the necessity to deepen the evaluation of the recycling of urban soils or plants submitted to urban contamination.
随着人们对城市土壤实际兴趣的增加，评估痕量元素对土壤的污染以及这种污染的动态变化对于保护植物和人类健康显得至关重要。街道树木及其附近道路坑中所涉及的土壤可以作为城市和交通对土壤和植物影响的便利指标。然而，这些土壤的数据仍然很少，许多研究调查的是公园土壤，而不是街道树木的土壤。此外，痕量元素可能是导致观察到的城市树木衰退的主要因素之一，而从业者越来越质疑在树木死亡后以及从街道上收集的树木落叶是否可以重新使用这些土壤。我们评估了法国巴黎各地街道树木（椴树）及其土壤中的人为痕量元素 (TE)，即 Zn、Pb 和 Cd 的污染情况。街道树木的土壤是在每棵新树种植时从农村地区进口的，因此树木的年龄与土壤在城市环境中的居留时间相对应，这允许评估土壤和树木中 TE 浓度的时间趋势。TE 浓度显示出严重的土壤污染，尤其是对较老的土壤（平均年龄为 80 年）。考虑到树木和土壤在城市环境中的居留时间，Zn 和 Pb 的积累量很大（分别约为 4.5 和 4 mg kg year）。然而，叶片中的 TE 浓度较低，表明与大气沉降污染相比，土壤-根系转移并不显著。这些结果强调了需要深入评估城市土壤或受城市污染的植物的回收利用。
