A rapid field procedure for screening trace elements in polluted soil using portable X-ray fluorescence (PXRF)

In this work, the potential soil contamination in the abandoned mining area of Rodalquilar (SE, Spain) is studied using portable X-ray fluorescence (PXRF). Measurements were made in situ, and data were statistically treated to study the spatial distribution of the anomalous values of trace elements. The elements exceeding the background values of the soils in the area were As, Pb, Zn, and Cu. Intervention levels both for agricultural as well as natural use in the area were exceeded by As concentrations, with 89% and 67% of the samples above these limits, respectively. The field observations and the spatial distribution of the data after the statistical treatment imply that the main mechanism of dispersion of the trace elements in soils of the area were water and wind erosion. PXRF is a useful tool for screening and assessing contaminated areas for quick and easy in situ determination of trace-element concentrations. After this study, the mobility and bioavailability of main potentially pollutant element (As) together with toxicity bioassays are necessary to estimate the potential environmental risk of the soils of the area.

Research Highlights
► The use of PXRF was used in an abandoned mining area.
► The spatial distribution of pollutants and background values was determined.
► The element exceeding the intervention levels in the area was arsenic.
► Toxicity assessments are necessary to estimate the potential environmental risk.