Effect of parent material and atmospheric deposition on the potential
pollution of urban soils close to mining areas
Abstract
The aim of this study is to analyse the concentration of potentially
toxic elements (PTEs) in urban soils under the influence of mining
activities and to determine its sources. For this purpose, topsoil
samples of the public parks and green areas in Minas de Riotinto (a town
next to one of the largest open pit mines in the world) and Aracena (a
nearby town outside the area of influence of the mine) were collected.
The concentrations of elements of interest (Cr, Co, Ni, Cu, Zn, As, and
Pb) were determined and compared based on soil location and origin (
in-situ or ex-situ), and with the background and
regulatory levels for the region. The elemental concentrations in the
fine fraction of the soils (particles <50 µm) were also
measured. The concentrations of some PTEs (Cu, As and Pb), also found in
the dust from nearby mines, were higher in the in-situ soils of
Minas de Riotinto than in those of Aracena. The concentrations of PTEs
in ex-situ soils of both towns were much lower than in
in-situ soils, and similar between both locations, revealing the
influence of the parent material as a primary source of PTEs. However,
the concentrations of As and Cu in the ex-situ soils of Minas de
Riotinto were significantly higher than the ones in Aracena, with a
significant increase of these elements in the fine fraction both for
in-situ and ex-situ soils. These two elements are directly
related to the mining activity, implying that atmospheric deposition of
dust from the mines also contributes to increasing the concentration of
PTEs in the soils of Minas de Riotinto. These pollution sources lead to
soils with potentially dangerous concentrations of pollutants, which
should be further studied and evaluated in relation to their long-term
influence on human health.