Can Olive Trees Be Used as Bioindicators of Pollution on the Island of Malta?

Olive trees are a distinctive and long-lived component of Mediterranean agro-ecosystems and could have the potential for dendrochemical investigations. To assess this potential, metal concentrations in young and old (60–370 14C years Before Present) olive wood, leaves, and soil from the Bidnija olive grove in Malta were analyzed using an acid-digestion and ICP-OES approach. Metal concentrations were low overall and those in wood were lower than in soils and generally lower than leaves, but there were no clear increases in metal concentrations in younger wood as hypothesized if pollution has increased over time. Our results suggest that olives do not appear to be a good dendrochemical proxy for changes in environmental chemistry, particularly in this minimally polluted environment.