Railway transport is a source of pollution to soils and living organisms by e.g. PAHs, PCBs, oil-derived products, pesticides and heavy metals. Soil toxicity evaluation requires chemical analyses, indicating the type and content of particular pollutants, as well as biological analyses, which allow assessing the reaction of organisms to these pollutants. This paper is focused on a multi-aspect evaluation of the degree of toxicity and pollution of soil in selected railway areas from north-eastern Poland by application of numerous biotests and chemical analyses. The soils were sampled on railway tracks from the following railway stations: Białystok Fabryczny, Siemianówka, Hajnówka, Iława Główna and Waliły. The most toxic soils occur on the railway tracks at Białystok Fabryczny and Siemianówka. They had a significant toxic effect on test organisms from various trophic levels. The contents of PAHs, PCBs, heavy metals, oil-derived hydrocarbons and pesticide residues were determined in the examined soils. In all cases the detected pollutants did not exceed the admissible levels. The highest content of oil-derived substances was noted in soils from Białystok Fabryczny and concentrations were moderate in soils from Siemianówka. Although the pollutants determined in soils from railway tracks did not exceed the admissible values, they had a toxic effect on numerous test organisms from different trophic levels. This suggests a synergistic effect of low concentrations (within the admissible levels) of several pollutants together, which resulted in a toxic effect on the organisms. Thus, there is a strong need of not only chemical, but also ecotoxicological analyses during the evaluation of environmental conditions. Based on data obtained from biological and chemical analyses, we concluded that railway transport may pose a hazard to the natural environment to a larger extent that hitherto expected.

The question of whether any specific plant species are typically growing along railway tracks (the so-called “railway-wandering plants”) has been discussed for many years. This study proves the existence of a form of Geranium robertianum species growing along railway tracks in North–Eastern Poland. Floristic studies have been carried out in 246 areas along railway tracks. This particular species was found in 70 studied areas (28 %). Comparative studies were carried out on 12 plant populations growing in the fieldwork and in glasshouse cultivation. Plants growing along the railway tracks in Waliły were different from all other studied populations. They were small (smaller by 31 %, max. by 57 % than other plants), with little leaf blades representing different shapes and colour. In studies of light absorption by photosynthetic apparatus (chlorophyll fluorescence) under conditions of exposure to high light intensity, the plants from Waliły were proved to have a better adaptation capacity to stress conditions. Increased levels of anthocyanins—which provided better protection of the photosynthetic apparatus against insolation—were shown. The protective properties against water deficiencies and excessive insolation were genetically preserved and were found in the second generation of plants cultivated in a glasshouse. For the first time, a new plant form of G. robertianum—a “railway-wandering plant” adapted to the conditions prevailing along railway tracks—was confirmed to exist. The form has developed probably after 1886, when the Białystok–Zubki railway was built, featuring the Waliły railway station.