Urban Sustainability at Risk Due to Soil Pollution by Heavy Metals—Case Study: Volos, Greece

Abstract

The focus of this case study is the meticulous observation of urban soil pollution by heavy metals (HMs), or, alternatively, potentially toxic elements (PTEs). The study took place in the urban center of Volos, Greece. Moreover, 248 soil samples were collected during 2018–2021 (62 samples annually), while 3.65 km2 was, approximately, the study area. The breakdown of total concentrations took place for the interpretation of different soil parameters, also according to mean values and medians of the total concentrations of HMs, the following decreasing order was monitored: Mn > Zn > Cr > Ni > Cu > Pb > Co > Cd. During the 4-year study, an increasing trend of metal concentration was observed (for each year compared to the previous one). Furthermore, the imaginary triangle, which was observed, is bordered by the historic train station, the two city bus and intercity coach stations and the commercial harbor. Statistical analysis was implemented in order to interpret the exceedances of HMs concerning the Directive 86/278/EEC. Principal component analysis (PCA) is an additional technique that was conducted because of the correlations and interdependences between the HMs. A strong correlation was observed between the HMs, but mainly between Cd and Zn, which is probably due to their common origin. During the COVID-19 pandemic, significant changes in metal concentrations were observed in different parts of the city, due to the limited movement of motorized wheeled vehicles, but also due to the long operating hours of the heating systems in the residential area. Further research is needed in the future in order to identify the sources of pollution and to find possible ways to reduce it. All in all, urban soil pollution by HMs is a great conundrum of the environmental aspect of sustainability.

Potentially Toxic Elements in Urban and Peri-Urban Soils – A Critical Meta-Analysis of their Sources, Availability, Interactions, and Spatial Distribution

“…Since 2000, several researchers started using a broader term, "anthropogenic soils", to include natural soils which although they were far from urban areas, were indirectly facing the consequences of human activities (Pouyat et al, 2020). Urban soils are formed either after prolonged human intervention or due to sudden and intense concentration of human activity in a certain location and in a given environmental background (Aslanidis & Golia, 2022;Papadimou et al, 2023). Unlike natural or agricultural soils, urban soils are influenced both by the local microclimate and the formation process, as they retain characteristics from the parent rock that affect their physicochemical properties and nutrient cycles (Golia et al, 2021b).…”

Biopotential of rhizobacteria to improve growth and phytochemical content in Javanese ginseng (Talinum paniculatum) herbal plant

“…Using a 100 mL measuring flask, the resultant solution was diluted with ion-free water and filtered until a filtrate was obtained. Additionally, AAS was used to examine the filtrates for mineral standards and metal grades (Aslanidis and Golia, 2022).…”

Urban chemistry as a new discipline exploring chemical and chemico-biological aspects of urban environment

“…Major impacts of human activities on urban ecosystems are demonstrated by changed degrees of environmental pollution during the COVID-19 pandemic in some cities. For example, in Volos, Greece, significant changes in metal concentrations were observed in different parts of the city during the pandemic, due to the limited movement of motorized vehicles, but also due to the long operating hours of the heating systems in the residential area [13].…”