Trace elements in natural surface soils in Sant Climent (Catalonia, Spain)

Abstract

Restoration returns an ecosystem to a state that is as similar as possible to its natural condition. Soil is a critical component of all ecosystems. To evaluate natural variations in concentrations of trace elements and to assess trace metal contamination in soils, it is necessary to survey trace metal background values. This study determines the concentrations of barium (Ba), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), strontium (Sr), vanadium (V), and zinc (Zn) (aqua regia-extractable) based on 22 representative natural (i.e. uncultivated) surface soils of the Sant Climent Municipal District (Catalonia, Spain); it establishes the geochemical baseline concentrations and investigates possible relationships between soil properties and trace element concentrations. The obtained geochemical baseline concentrations (mg kg −1) were Ba 146.0–561.0, Cr 13.8–115.0; Cu 11.0–92.2; Ni 12.4–130.6, Pb 11.7–152.7, Sr 17.5–146.2, V 11.5–121.2, and Zn 10.7–356.0. Soil properties, including pH w, organic carbon (OC), clay fraction, cation-exchange capacity (CEC), total Fe, and total Al concentrations were related to metal concentration using correlation analysis. Total Fe and Al showed the strongest relationships with concentrations of most trace elements.