Spatial distribution of thallium in the soils of North Macedonia

The aim of the study was to determine the spatial distribution and assessment of thallium contam- ination in the soils of North Macedonia. Topsoil samples (0–30 cm) were collected from 995 locations throughout the country in a grid of 5×5 km between sampling points. The soil samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using the total digestion method. The distribution of thallium in the soils according to the eight statistical regions of the country is discussed, as well as the distribution based on the 15 most common geological formations and the distribution based on 13 pedological units. The thallium content varied in Macedonian soils from <0.05 to 15.5 mg/kg (median 0.70 mg/kg), which corresponds to the total Tl content for the European soils with a range of 0.01 to 21.3 mg/kg and a median of 0.66 mg/kg. The spatial distribution patterns of Tl in the collected soil samples are mainly determined by the geology (parent material and mineralization). In some areas, the natural anomaly pattern is overlaid by anthropogenic emissions from past and present mining, ore processing and associated metal industries.