Assessment of Cu and Zn contamination and associated human health risks in urban soils from public green spaces in the city of Thessaloniki, Northern Greece

Sustainable patterns of production and consumption dictate waste elimination and the modest use of resources in uncontaminated environments. However, this is not always possible, especially in urban settings, since soils may be enriched with various metals and metalloids, and this may pose a threat to the city’s residents. Urban soils have not received the same degree of interest as agricultural soil, where crops are cultivated, but the risk of exposure of humans to soil pollutants is real in urban settings. For this reason, in the present study, soil samples from public green spaces in Thessaloniki, Northern Greece, were collected in March 2022. Soil physicochemical characteristics (% of sand, silt and clay, pH and electrical conductivity) as well as the pseudo-total concentrations of Cu and of Zn (mg/kg dry weight soil) were determined for 50 distinct sites in the city. The risk to inhabitants was determined for the oral and dermal routes in both adults and children. The pseudo-total concentrations of Cu and of Zn were variable, with some sites exhibiting concentrations higher than the EU set limits for soil treated with municipal sludge or than the Canadian Soil Quality Guidelines. The risk to adults and children was acceptable in every case. The high correlation between the Cu and Zn pseudo-total concentrations as well as the locations of the most polluted sites point to input from anthropogenic activities. These activities may include train and automobile traffic, as well as operations within the city's commercial and passenger port. Even though it is not as well studied as soil pollution in agriculture, soil pollution in cities should be given proper attention.