Conclusions
The vineyard soils display a heterogeneous concentration in terms of elemental composition in the study area, with Ca being one of the most abundant major elements and S below the average world background values. The small differences between the concentrations of the elements with depth can be explained by assuming a common source that is primarily geogenic and pedogenic in nature followed by secondary factors of ploughing and agricultural practices.
Regarding the pedogeochemical baseline levels, and despite the fact that the use of fertilizers and pesticides in the vineyard is common, we can describe the trace element contents as normal for the investigated area, that is, trace element values associated with potential toxicity in soils were not found. Indeed, a risk assessment of the elementary composition of the soils indicated that this does not currently pose a high risk and that there are no adverse effects caused by PTEs accumulation in the soils. This is because the farmers are very sensitive to the environment and they aim to achieve only moderate yields of grapes per hectare.
The relationships between concentrations of elements in soil versus leaves indicate that the higher soil contents in Sr, Pb and Cr imply higher contents of these elements in the leaves, while the V content decreases in leaf as it increases in the soil. It was found that some elements were not taken up by the Vitis vinifera , even though elements like Zr and Rb are present in relatively high concentrations in the soil.
In conclusion, the present study provides a reference for future analogous studies in other areas, particulary in a Mediterraenn environment, but additional research on trace element contents in grape clusters is required to understand better the transfer of trace elements from soil to products (grapes and wine).