Urban Soil Pollution by Heavy Metals: Effect of the Lockdown during the Period of COVID-19 on Pollutant Levels over a Five-Year Study

When residents of Volos, a city in central Greece, are trying to recall their daily life after the end of the quarantine due to COVID-19, the soil pollution survey provided valuable insights, which are compared with a 4-year study carried out in that area before the pandemic period. Using appropriate indices, namely contamination factor (CF), pollution load index (PLI), geo-accumulation index (I_geo), ecological risk factor (E_r), and potential ecological risk index (RI), and using geostatistical tools, maps were constructed for each metal (Cu, Zn, Pb, Ni, Cd, Co, Cr, Mn). Variations in the values of the contamination indices showed a significant redistribution in pollutant load from areas previously polluted by high vehicle traffic and the activities of the main port to the residential areas, where the habitants have their homes and playgrounds. The study showed that Cu, Zn, Pb, and Co concentrations increased during the pandemic period by 10%, 22.7%, 3.7%, and 23.1%, respectively. Ni’s concentration remained almost constant, while Cd, Cr, and Mn concentrations were decreased by 21.6%, 22.2%, and 9.5%, respectively. Fluctuations in the concentrations and corresponding contamination and ecological indices of the elements can serve as a means for highlighting potential sources of pollution. Therefore, although the pandemic period created anxiety, stress, and economic hardship for citizens, it may prove to be a valuable tool for investigating the sources of pollution in urban soils. The study of these results could potentially lead to optimal ways for managing the environmental crisis and solve persistent problems that pose risks to both the soil environment and human health.