Profile distribution of mercury in selected urban soils / Profilowe rozmieszczenie rtęci w wybranych glebach miejskich

With the expansion of urbanization, the increase of pollutants in air, soil and water is observed. The major source of Hg in urban soils is fossil fuel combustion, and these soils become important indicators of contaminants in the soil environment.

The aim of the research was to determine the distribution of mercury in urban soil profiles on the basis of their physicochemical properties and origin.

Analysed soils come from the city centre of Bydgoszcz, from park and square areas intended for recreation. Research was conducted on four soil profiles: Mollic Regosol (Technic), Skeletic Regosol (Technic), Eutric Regosol (Loamic), Eutric Regosol (Endoclayic). Determined in most profiles artefacts were pieces of bricks, concrete, glass, garbage, slag, asphalt, tar, and charcoals in proportion up to 25% of the volume. In soil samples basic soil parameters and the total content of mercury were determined (using atomic absorption spectrometer AMA-254).

Determined parameters and the total mercury content of analysed soils of Bydgoszcz city were typical for urban areas, and the soils were classified as noncontaminated of this metal (total Hg content 0.009-1.114 mg.kg-1, mean 0.218 mg.kg-1). In most analysed soils the source of Hg was atmospheric deposition and addition of human-made materials. It was confirmed by significant correlation coefficient -0.415 (p<0.05), calculated between Hg content and percent of course fragments (Ø>2mm), among which artefacts were very common. Profile distribution of mercury was mainly the result of antropopression but also the concentration of Hg in parent material. Spatial differentiation of Hg content between tested soil profiles was related with localisation (vicinity of heavy traffic roads).