Can rail transport-related contamination affect railway vegetation? A case study of a busy railway corridor in Poland.

Rail transport is considered a serious risk to the environment; however, its environmental impact has been addressed insufficiently with many resulting uncertainties. A busy railway corridor was used to determine if the side of a railway track could distort the assessment of soil contamination with potentially toxic elements (PTEs) and if soil phytotoxicity changes up to 50 m away from the track. The studied soils showed a moderate to heavy level of contamination with Cu, Ni, Pb and Zn. Cu, Ni and Zn content decreased significantly with the distance from the track while Pb content increased slightly, probably because the Pb came predominantly from exhaust gases, while the source of the remaining elements was the abrasion of railway infrastructure components. The side of the railway track proved to be a significant factor that influenced Ni and Pb content in particular. The phytotoxicity test predominantly showed a slight inhibition of plant growth with a maximum value reaching 70.4% but with an absence of significant differences in phytotoxicity between the distances. The ecological risk assessment did not reveal a serious threat to the environment from the PTEs in the soil. Based on the results, it is appropriate to define a heavily polluted zone at a minimum distance of 50 m from the track, and both sides of the railway track should be assessed so that the actual level of contamination is not underestimated. Further research is needed on this issue urgently due to the severe and hitherto overlooked environmental risks associated with rail transport.

Polluted brownfield site converted into a public urban park: A place providing ecosystem services or a hidden health threat?

The conversion of old brownfield sites into places once again serving society is becoming an upward global trend, especially in urban areas. Due to the increasingly growing pressure on the expansion of urban green spaces, such sites can become, for instance, urban parks. The aim of the study was to assess whether the solution is appropriate and if it does not pose a potential health risk. Heavy pollution of soils was found out by means of the example of the urban park newly established in a reclaimed area of a historic mining town. The high average values in the topsoil were found out mainly in As (132 mg/kg), Cd (6.8 mg/kg), Pb (535 mg/kg) and Zn (1604 mg/kg). The assessment of the non-carcinogenic health risk has revealed possible As-related adverse health effects in children even at irregular park visits. According to the carcinogenic risk assessment, As, Cd, Cr and Ni can be ranked in the category of an acceptable total risk for regulatory purposes. The health status of park vegetation as a significant component of the urban ecosystem was also assessed. Soil phytotoxicity brought about severe damage to the seedlings, with a mortality rate of up to 84% locally. The results indicate that heavily polluted brownfield sites with historic mining-related activities are not suitable for establishing urban parks even after reclamation and nature-based solutions may not be invariably appropriate. Based on the findings, the management steps that ought to be implemented in the process of brownfield redevelopment into the urban park even after its establishment have been highlighted in order to minimize the health risk to park visitors while providing the required ecosystem services by vegetation.

Human health and ecological risk assessment of trace elements in urban soils of 101 cities in China: A meta-analysis.

Urban soils pollution by trace elements arouses the growing interest in China. The aim of this study was to assess urban soil pollution by As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in China and the possible impacts on urban inhabitants and urban green spaces (UGS). Data from more than 17,000 samples were applied to characterize the status of 101 cities. The pollution assessment proved that 11% of the cities are heavily polluted. According to the Hazard Index, the value of risk for the infant population in 15 cities exceed the standardly accepted tolerable levels. The carcinogenic risk assessment demonstrated the potential threat in the cities with the total population approximately 20,566,900. Cr and As were detected to be the most hazardous elements. UGS may be seriously threatened by trace elements toxicity in 38 cities. Cd was found to be the riskiest element for UGS. Ecosystem services of UGS can be significantly disrupted under the current situation in China and their status is expected to deteriorate in the future. For this reason, it is essential to alter the policy of the urbanization process and develop functional concepts of urban green infrastructures adapted to the high level of contamination which shall improve human well-being in China.

The impact of tourism on extremely visited volcanic island: Link between environmental pollution and transportation modes.

The enormous tourism boom raises concern about possible negative environmental impacts worldwide. One of the risks posed by tourism may be heavy metal pollution. On the example of the volcanic island of Santorini, a popular tourist destination, pollution of soils categorized according to the tourism load was monitored. Significant anthropogenic contamination by heavy metals, especially Cu, Cr and Pb, was found out. This contamination may constitute a moderate ecological risk to the island ecosystems. Tourism has been shown to be a significant pollution factor as evidenced by the contaminated soils near the airport. Simultaneously, airport traffic has been proved to be an important emitter of Co, Cr and especially Zn. The comparison with other volcanic islands has shown that on Santorini the content of heavy metals in soils is significantly lower, despite frequently higher tourism intensity. On this basis, it can be concluded that in case of volcanic islands the dominant factor determining the content of heavy metals in the soil is the parent rock. Given high and ever-increasing intensity of tourism on the island, it can be assumed that soil contamination will continue to rise rapidly. Therefore, without proper steps reducing tourism, increase in soil degradation, growing negative impacts on local ecosystems as well as on the quality of produced wine can be expected on Santorini.