Multiple Factors Influence the Accumulation of Heavy Metals (Cu, Pb, Ni, Zn) in Forest Soils in the Vicinity of Roadways

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