Leaf biochemical responses and fruit oil quality parameters in olive plants subjected to airborne metal pollution

- Olive trees and fruits exposed to airborne metal pollution were studied for two years.
- High levels of Cd, Cu, Fe, Mn, Ni and Pb were found on the fruits but not in the oil.
- A depression of the antioxidant system and changes in hormone levels occurred.
- Atmospheric metals negatively affected olive oil chemical and sensory quality.
- Airborne metal pollution could indirectly have negative effects on oil consumers.

This study was carried out in two olive orchards (Olea europaea L., cv. Chemlali) located in a polluted area near a fertilizers factory and in a control unpolluted site, managed with similar cultivation techniques. The aim was to investigate the physiological and biochemical responses of polluted plants (PP), exposed to atmospheric metal contamination (Cd, Cu, Fe, Mn, Ni and Pb) as compared to control plants (CP). Leaves, roots and fruits of PP showed a depression of their non-enzymatic and enzymatic antioxidant defences and a disruption of their hormonal homeostasis. The anomalous physiological status of PP was also demonstrated by the lower values of pigments in leaves and fruits, as compared to CP. Atmospheric metals negatively affected olive oil chemical and sensory quality. However, despite metal deposition on fruit surfaces, the accumulation of potentially toxic metals in olive oil was negligible. Considering that olive oil is an important food product worldwide and that many productive olive orchards are exposed to several sources of pollution, this work could contribute to clarify the effects of atmospheric metal pollution on olive oil quality and its potential toxicity for humans.

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