Although growth stimulation at low arsenic doses was observed in several plants, few studies have focused on this phenomenon in more detail. The effects of different concentrations of arsenic (0–50 mg kg⁻¹ of soil: As0–As50) on the growth and selected physiological parameters of two maize cultivars (Zea mays L. cvs. Chapalu and MvNK 333) were tested. Cultivar MvNK 333 manifested a generally higher tolerance to As than cv. Chapalu, which may be related to the lower content of As in the tissues. The highest stimulatory effect of As was recorded at doses of As1 and As2 (cv. Chapalu), and at the As5 dose (MvNK 333), there was an increase in shoot elongation, biomass, and relative water content (RWC), as well as the content of photosynthetic pigments. The stimulatory effect of lower doses of As apparently represents an adaptation mechanism that is associated with water content regulation in the given conditions. The stomata of the studied cultivars were involved in this regulation in different ways. While cv. Chapalu exhibited increased numbers of stomata on both sides of leaves, cv. MvNK 333 instead responded to the given conditions with decreased stomata size. Although hormetic manifestations closely related to changes in stomatal number and size were observed, a typical stomatal hormetic response was not observed in the given range of As doses.

Toxicity assessment of K₂Cr₂O₇, ZnCl₂ and NiCl₂.6H₂O focusing on the green unicellular alga Desmodesmus subspicatus showed that Ni was the most toxic (EC₅₀ = 0.121 mg L⁻¹), followed by Cr (EC₅₀ = 0.357 mg L⁻¹) and Zn (EC₅₀ = 0.968 mg L⁻¹). The alga was exposed to solutions of the individual metals and their mixtures (Zn + Ni, Zn + Ni + Cr). After 48, 72 and 96 h of exposure, the accumulation of Zn, Ni and Cr in algal cells was assessed. Moreover, the change in toxicity of the metals, the concentration of selected biogenic elements (Ca, Na, Mg, S, K, P, Mn) in algal cells and the rate of metal removal from the solutions were also analysed. In the case of single-metal solutions, for Zn and Cr, the toxicity and accumulation in algal cells decreased over the 96 h of the experiment, whereas for Ni as well as for the binary and ternary mixtures the toxicity and accumulation increased. Significant correlations between the amount of metals accumulated in the cells and the inhibition of growth rates were observed. The content of selected biogenic elements in algal cells decreased over time in all treatments with added metals as well as in the control group, and after 96 h was higher in all treatments with addition of Ni compared to the control group and single-metal solutions of Zn and Cr. The highest removal of the metal from the solution occurred in the case of the single metal solution of Zn, where 83.4% of Zn was removed from the solution in 96 h.

Construction of motorways and road traffic bring a new line element into the landscape, which fundamentally influences the local hydrological regime and water quality. Impermeable surfaces are introduced into the landscape, affecting the natural infiltration of water in the environment. The aim of the present research was to assess the long-term historical development of changes in the landscape retention potential due to construction of the D1 motorway in the Jihlava region and also evaluate the impact of winter maintenance on the quality of surface waters and soils. During the reference period, the research area showed an increase in land take and related increases in soil sealing by impermeable surfaces due to the construction of the D1 motorway. This fact has clearly contributed to the deterioration of the retention potential of the landscape in the area. Chloride concentrations of both matrices were evaluated in relation to the amount of de-icing salt applied at the sites and precipitation recorded in this region. Water samples collected at the outflow contained in all cases higher concentrations of chloride than samples of the inflow water. The highest chloride concentration in soil was measured in samples collected at a distance of 2 m from the road.

The paper deals with an analysis of the amount of 16 polycyclic aromatic hydrocarbons (PAHs (Polycyclic aromatic hydrocarbons—16 defined by US EPA.)) released from reclaimed asphalt mixtures used in base layers of road surfaces and in binder layers in road construction using cold in-place recycling. For the ten samples tested, the sum of 16 PAHs was determined directly for the crushed asphalt mixture and for its 24-h leachate. The crushed asphalt samples were used to make cylindrical asphalt specimens of the cold recycling mixture. The asphalt specimens were prepared to simulate as realistically as possible the use of the mixtures in road reconstructions implementing the cold in-place recycling technology, which should ensure the passivation of PAHs. The asphalt specimens were subjected to a dynamic leaching test under laboratory conditions with regular replacement of the leaching liquid. The results showed that the concentration of PAHs released into the water environment from the test specimens (passivated material) was approximately 40–50% lower than the amount of PAHs released from the asphalt mixtures in the 24-h leaching test. When compared to the input PAH concentrations in the asphalt mixtures (36–1323 mg.kg⁻¹), on average, only 0.15% of PAHs is released from the passivated material. Dynamic leaching test has shown that the wrapping of the original asphalt mixture with a new binder and its subsequent compaction leads to the preservation of PAHs in the original material at such a level that their total concentrations are reduced by two orders of magnitude.