A considerable amount of data files from projects of the RECETOX centre were collected for purposes of this study; further data were obtained from two major research institutions involved in monitoring of soils: CISTA (Central Institute for Supervising and Testing in Agriculture) and ANLP (Agency for Nature and Landscape Protection).
Fig. 1Overview of sampling sites used for spatial modelling
Geographic information systems (ArcGIS) were used to obtain the underlying layers of other variables that affect POPs occurrence in soils. The variables were the type of soil, character of soil, vegetation type, altitude, average annual temperature, rainfall, distance from roads, industrial and residential areas and presence of contaminated sites.