Data for “Intra- and inter-site variability of soil contamination in road shoulders – Implications for maintenance operations”

The reported data have been acquired within a research project investigating soil contamination in vegetated road shoulders. The methodology was designed to assess (i) the spatial distribution of three metals (copper, lead and zinc) and 16 PAHs (classified as priority pollutants by the US-EPA) within each sampled site, and (ii) whenever possible, influencing factors for the inter-site differences in contamination levels. The study area covers approximately 6,000 km² in the eastern part of the Paris region (France), with a strong urbanization gradient from east to west. Forty road segments were selected to encompass most of the territory’s soil types, environments (scattered dwellings, open countryside, forest), and traffic characteristics. At each site, soil samples were collected at four to five distances from the road, depending on the shoulder width. For each distance, a composite sample was formed from 6 evenly spaced points along a transect parallel to the road. The targeted depth corresponded to the upper 5 centimeters, however in some cases the presence of the road sub-base only allowed the collection of a surface sample (0-2 cm). All samples were analyzed for metals, whereas only two samples from each site could be analyzed for PAHs due to cost constraints: it was chosen to retain (i) a composite sample formed by merging subsamples collected at 0 and 0.3 m, and (ii) a sample collected on the opposite side from the road. Further details are provided in the appended file entitled “Data description”. The other files present: • Site characteristics: site index (number from 1 to 40 and official French nomenclature), GPS coordinates of the site, annual average daily traffic, truck fraction. • Metals and PAHs: site index, sampling distance, concentrations of each individual substance analyzed in the corresponding sample. The results are presented and discussed in the following research article: D. Tedoldi, R. Charafeddine, P. Branchu, E. Thomas, M.-C. Gromaire (2021) Intra- and inter-site variability of soil contamination in road shoulders – Implications for maintenance operations. Science of the Total Environment.本研究数据源自一项针对植被覆盖道路路肩土壤污染的科研项目。本研究方法旨在完成两类评估：（i）各采样点位内三种金属（铜、铅、锌）与16种多环芳烃（polycyclic aromatic hydrocarbons, PAHs，被美国环境保护署（US-EPA）列为优先管控污染物）的空间分布特征；（ii）在条件允许的情况下，探究造成点位间污染水平差异的影响因素。 研究区域位于法国巴黎大区东部，总面积约6000平方千米，存在由东向西逐步强化的城市化梯度。研究共选取40条道路路段，以覆盖研究区域内绝大多数土壤类型、环境场景（分散住宅、开阔郊野、林地）及交通特征。根据路肩宽度差异，每个采样点位沿垂直于道路的方向设置4至5个采样距离梯度。每个距离梯度下，沿与道路平行的样带选取6个等间距采样点，混合制成复合样品。 目标采样深度为地表以下5厘米，但部分路段因道路基层存在，仅能采集0-2厘米的表层样品。所有样品均开展金属元素检测；但受成本限制，每个点位仅能选取两份样品进行多环芳烃检测：其一为0米与0.3米处采集的子样混合制成的复合样品，其二为道路另一侧采集的样品。 更多细节详见题为《数据描述》的附加文件。其余附件文件包含： • 点位特征信息：点位编号（1至40的序号及法国官方命名）、点位GPS坐标、年平均日交通量、货车占比。 • 金属与多环芳烃含量数据：点位编号、采样距离、对应样品中各检测物质的浓度值。 本数据集的研究结果已在以下学术论文中发表并讨论：D. Tedoldi、R. Charafeddine、P. Branchu、E. Thomas、M.-C. Gromaire（2021）《路肩土壤污染的点位内与点位间变异及其对养护作业的启示》，《总体环境科学》（Science of the Total Environment）。