The aim of the research was to evaluate the influence of car traffic on the content of selected heavy metals in soil from a park area, and to define the dependency between their content and enzyme activity. Soil samples were collected from 13 points located along a communication route, each 100 m from the next and 50 m from the border of the road. Soil material was obtained from two depths (0–20 cm and 20–40 cm) and analysed for: pH in H₂O and in KCl, OC, and texture by laser method. Total content of heavy metals (Pb, Cd, Zn, Cu, Ni), available phosphorus and the activity of selected enzymes: catalase, dehydrogenase, acidic and alkaline phosphatase were all determined. The examined soils have the texture of loamy sands or sands (USDA 2012), slightly acidic or neutral pH, Organic Carbon (OC) content in the range from 3.50 to 13.80 g kg⁻¹. The total contents of elements in surface horizons were, in order of decreasing concentrations: Pb>Zn>Cu>Ni>Cd, although in subsurface horizons it was Zn>Pb>Cu>Ni>Cd. Contamination Factor (CF) determined for Ni, Pb, Cd, Zn, Cu reaches higher values in samples from subsurface horizons, which confirms the influence of car traffic on the content of heavy metals in the surrounding soils. The calculated CF shows contamination is moderate for Ni, Cd, Zn and Cu and high for Pb and Cu. The investigated soils may be classified as class IV (low) in terms of available phosphorus. The activity of the examined enzymes was higher in soil samples collected from the 0–20 cm layer than from 20–40 cm. The correlation analysis indicates a significant positive dependency between OC content in soils and enzymatic activity. Principal Component Analysis (PCA) was also performed. Two principal components PC1 and PC2 account for 66.57% of the variability.

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.

The aim of the research was to determine the effect of lithogenic and pedogenic processes on the formation of Luvisols from the area of Vistula glaciation on the base of profile distribution of iron oxides and total iron in relation to texture and physicochemical properties. The indices of weathering of the soil material in genetic horizons were calculated, and changes in the content and forms of iron oxides were evaluated. The predominant type of soil in the study area is Luvisols under agricultural use, formed from silt formations on loam. The analyses were made applying the following methods: grain size composition using the sieve method and hydrometer method, the interpretation of the results was performed according to the World Reference Base for Soil Resources classification, the pH of soils was measured with the potentiometric method, C-organic with the Walkley-Black dichromate method, the content of the following iron forms was determined (total iron (Fe_t) after the mineralization of soils in the mixture of HF and HClO₄ acids), free iron oxides were extracted using dithionite-citrate-bicarbonate method, and amorphous iron oxides after the ammonium oxalate extraction (using the Philips 9100PU apparatus). The clay mineralogy was estimated by X-ray diffraction analysis. It was observed that total iron enrichment occurs in argic horizons accompanied by iron depletion in luvic horizons, while the profile distribution of iron is similar to the distribution of clay. The (Fe_d/Fe_t) ratio indicates a low degree of weathering; the highest values were observed in argic (Bt) horizons, which confirms the effect of the process of pedogenesis on the value of that index. In the soils investigated, crystalline iron oxides generally dominate over the amorphous forms. The mineralogical composition of clay fraction separated from the upper part of soils was different as compared to the underlying material. The results of the study showed that iron contents (together with the other indicators) and its forms can be used to distinguish soil layers of different origin. The depth distribution of Fe_d, Fe_o and Fe_t within soil profiles indicates that the soil material may be of different lithogenic origin in the studied pedons.

Purpose: The study aims to assess the impact of human activity on the content and migration of trace elements in soil profiles of various physico-chemical properties. The research hypothesis assumed that human impact related to the functioning of buildings, agriculture, industry and communication negatively affected the trace element contents and physico-chemical properties of soils in a selected urban area (the Grudziądz Basin). Materials and methods: Seven soil exposures were made in areas that differed in land use and soil type over an area totalling approx. 200 ha. In the soil profiles, samples of soil of disturbed structure were taken from each genetic horizon. Selected physico-chemical properties of soils were determined: soil texture, soil pH, TOC, CaCO3 content. The total content of heavy metals in the soils was determined by AAS after digestion in hydrofluoric acid and bioavailable forms in 1 M DTPA. The sources of elements in the studied soils were assessed using the following indices: Enrichment Factor (EF), Geoaccumulation Index (Igeo) and Contamination Factor (CF). Results and discussion: The sand fraction dominated the examined soil profiles, with its content ranging widely and averaging 64.7%. In general, the humus horizons had lower pH values than the deeper layers and parent rock horizons. The organic carbon content ranged from 0.07 to 4.64%. The vertical decomposition of total N was strongly related to the decomposition of organic carbon. The highest metal contents in the soil samples were for zinc, and then for nickel. Conversely, the lowest concentrations were for mercury. Most of the profiles had higher contents of the analysed elements in their upper horizons. The humus horizons were characterised by the accumulation of Cr, Hg, Zn and Fe. The samples from the soil profiles were highest in bioavailable forms of zinc and nickel. Conclusions: The assessment of human impact on the concentrations and migration of trace elements in profiles of agricultural soils found the contents of heavy metals to be variable. Only in a few profiles were EF values for Cd, Pb and Ni found to indicate the effects of human activity. Likewise, CF and Igeo attest to only slight contamination in the research area.