Intensified vehicular traffic causes increased heavy metal contamination of the environment. We investigated the heavy metal chemistry of soils located under silver fir stands in the vicinity of Poland’s S7 roadway. Three sampling sites were located in fir stands in central Poland. Fieldwork included soil sampling of the organic (O) horizon and mineral (A) topsoil. We analyzed the soil pH, carbon (C) and nitrogen (N) concentration, and the HCl-extractable forms of sodium (Na) and heavy metals: copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). The stoichiometric ratios Cu:C, Ni:C, Pb:C, and Zn:C were also calculated. In all sites, a higher Na concentration was found in the 0–10 m from the forest edge. This zone was characterized by increased pH in the O horizon, increased Zn and Ni in the A horizon, and a decreased Pb in the O horizon. There was no clear pattern for the Cu concentration. The Ni:C and Zn:C ratios were correlated with pH, while Pb:C and Cu:C ratios were correlated with the clay minerals. HCl-extractable Ni and Zn concentrations in A horizon were greater near the roadway, revealing strong pH dependency. The roadway affects the geochemical background of the topsoil in the nearby fir stands. Mechanistically, we suggest that Na increases the soil pH and therefore enhances the ability of soil organic matter to bind Ni and Zn by releasing hydrogen from soil organic matter functional groups into the soil solution. A depleted Pb near the road was likely owing to the strong competition from Na.

车辆通行加剧导致对环境的重金属污染增加。我们调查了位于波兰S7公路附近的冷杉冷杉林下土壤的重金属化学性质。三个采样点位于波兰中部的冷杉林中。野外工作包括对有机（O）层和矿物（A）表层土进行土壤采样。我们分析了土壤的pH值，碳（C）和氮（N）浓度以及钠（Na）和重金属（铜（Cu），镍（Ni），铅（Pb）和锌（锌）。还计算了Cu：C，Ni：C，Pb：C和Zn：C的化学计量比。在所有站点中，在距森林边缘0-10 m处都发现较高的Na浓度。该区域的特征是O层的pH值升高，A层的Zn和Ni含量增加，O层的Pb含量降低。Cu浓度没有明确的模式。Ni：C和Zn：C比值与pH相关，而Pb：C和Cu：C比值与粘土矿物相关。在巷道附近，A层中可提取的HCl的Ni和Zn浓度较高，显示出强烈的pH依赖性。巷道影响附近冷杉林中表土的地球化学背景。从机制上讲，我们认为Na可通过将土壤有机质官能团中的氢释放到土壤溶液中来提高土壤pH值，从而增强土壤有机质与Ni和Zn结合的能力。由于Na的激烈竞争，道路附近的Pb可能已耗尽。在巷道附近，A层中可提取的HCl的Ni和Zn浓度较高，显示出强烈的pH依赖性。巷道影响附近冷杉林中表土的地球化学背景。从机制上讲，我们认为Na可以通过将土壤有机质官能团中的氢释放到土壤溶液中来提高土壤pH值，从而增强土壤有机质与Ni和Zn结合的能力。由于Na的激烈竞争，道路附近的Pb可能已耗尽。在巷道附近，A层中可提取的HCl的Ni和Zn浓度较高，显示出强烈的pH依赖性。巷道影响附近冷杉林中表土的地球化学背景。从机制上讲，我们认为Na可以通过将土壤有机质官能团中的氢释放到土壤溶液中来提高土壤pH值，从而增强土壤有机质与Ni和Zn结合的能力。由于Na的激烈竞争，道路附近的Pb可能已耗尽。我们认为Na可以通过将土壤有机质官能团中的氢释放到土壤溶液中来提高土壤pH值，从而增强土壤有机质与Ni和Zn结合的能力。由于Na的激烈竞争，道路附近的Pb可能已耗尽。我们认为Na可以通过将土壤有机质官能团中的氢释放到土壤溶液中来提高土壤pH值，从而增强土壤有机质与Ni和Zn结合的能力。由于Na的激烈竞争，道路附近的Pb可能已耗尽。