To understand the behaviour of mercury in soils and assess the risk of its toxicity, the forms in which the element is found in the environment must be detected. In the occurrence of favourable alkylation conditions (for example in floodplain soils), the content of methyl and ethyl mercury is higher. These Hg forms in comparison with mineral compounds are toxic for the same organisms in concentrations from 10 to 100 times lower. The research concerned eight selected soil profiles representing six different types of soils (Endogleyic Phaeozem, Endogleyic Fluvisol, Eutric Fluvisol, Haplic Luvisols, Brunic Arenosol, Albic Podzol) placed in croplands. The content of mobile (water soluble), available (DTPA-extractable) and bound with organic matter (NaOH-extractable) Hg forms was determined after thermal decomposition using AMA mercury analyser. The mobility as well as availability of mercury in the analysed soils was very low, with average percentage to 0.28 and 2.45 % of the total content of this metal, respectively. It was mainly dependent on texture, the amount of organic matter and soil pH. The percentage of mercury bound with organic matter ranged from 2.34 to 73.70 % of the total content of this metal and was correlated with amount of clay and Fe oxides. Considering these results, the hazard of migration of this element into deeper horizons of the soil profile and ground water is very low. Moreover, crops from the investigated area are not at risk from mercury contamination.

Recent years have witnessed intensification of road traffic and, with it, the amount of substances emitted by vehicles. Such emissions need to be monitored for public health purposes. The aim of this study was to evaluate the impact of the highway traffic on the total content and bioavailability of Zn, Cu, Ni, Cd, Cr and Pb in nearby soils as well as influence of an acoustic screen on spatial distribution of the metals. The material included 40 soil samples collected from 15 research points located 5, 10, 25 and 50 m away from the road acoustic screen and from 4 points between the screen and the highway. Additionally, 5 research points were located next to the metal barrier. Selected physicochemical properties of soils were determined: soil texture, soil pH, TOC and CaCO₃ content. The total content of heavy metals in the soils was determined by AAS after digestion in aqua regia and bioavailable forms in 1 M diethylenetriaminepentaacetic acid. The research found low impact of the highway traffic on the content of heavy metals in soils; however, due to a very short period of this potential impact (5 years), the moderately polluted category of geo-accumulation index of cadmium and high bioavailability of lead indicate the need of repeating the research within the next several years. Furthermore, the road acoustic screen significantly influenced spatial distribution of the metals in soils.

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 (p2mm), 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).