Health and Ecological Risk From Potentially Toxic Elements in Soils and Extra Virgin Olive Oils From Valdichiana Senese, Tuscany (Italy)

Background

Extra virgin olive oils (EVOOs) are widely consumed but rarely analysed for potentially toxic elements (PTEs), whose concentrations in EVOOs can be significantly influenced by contamination in olive grove soils. As food consumption is the main PTE accumulation pathway in humans, thorough investigation on EVOOs is necessary.

Aim

The concentrations of 12 PTEs were determined in olive grove soils and EVOOs from Valdichiana Senese (Southern Tuscany, Italy), with the aim of identifying any contamination by PTEs in olive grove soils and evaluating the associated ecological risk as well as of assessing the potential risk for human health related to PTE intake from EVOO consumption.

Methods

The soil and EVOO samples were collected from 18 farms, and the concentration of As, Cd, Co, Cr, Cu, Ni, Pb, Sb, Tl, U, V and Zn was determined by inductively coupled plasma mass spectrometry (ICP–MS). The data were used to calculate the health risk index (HRI) for EVOOs and the geoaccumulation index (I_geo) and potential ecological risk index (PERI) for soils.

Results

Analytical data suggested that the PTE concentrations in the investigated olive grove soils are natural as comparable to their normal geochemical background in soils from Southern Tuscany formed from the same parent rocks of Valdichiana Senese soils or due to local geogenic enrichments in some parent rocks. Among the analysed PTEs in the EVOO samples, Zn, Cu and Ni had the highest concentrations, followed by Cr and Pb. Most PTEs showed a high variability of their concentrations in EVOOs from Valdichiana Senese.

Conclusion

On the basis of values of indices applied to PTE concentrations in the soil samples, a low-to-moderate Cu contamination emerged only in the olive grove soils of two farms, probably as a consequence of the diffuse use of Cu-based products in agriculture, and overall, the ecological risk was low. Furthermore, although EVOOs from Valdichiana Senese have somewhat slightly high concentrations of some PTEs such as Cu and Zn, the health risk associated with their intake through the EVOO consumption is definitely negligible.