Temporal Variations of Heavy Metal Sources in Agricultural Soils in Malta

Abstract

In the opportunity to understand the benefits of Maltese soil and its importance to our climate, the content of heavy metals—including Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn—was studied in two fields in proximity in the south-east region of Malta. Analytical determinations were carried out using atomic absorption spectroscopy following heated aqua regia digestion on 50 collected samples using triple repeatability. The decreasing pattern of the concentrations obtained is Fe > Zn > Mn > Sr > Pb > Cu > Ni > Cr > Co. Correlations between pre-harvesting and post-harvesting concentrations were examined to assess lithogenic and anthropogenic relationships. Multivariate analysis including principal component analysis and factor analysis clarified the origin of heavy metals content reviewed. Some of the heavy metals studied showed a dominant relationship between concentration variation and their possible sources. Potential ecological risk assessment demonstrated that the fields reviewed are not contaminated by any of the heavy metals assessed except for Zn which posed a moderate/strong contamination but presented an overall low potential for ecological risk. Concentrations of heavy metals demonstrated no risk to human health and no carcinogenic risk through ingestion and dermal contact with the soil.

Assessment of Heavy Metal Distributions in Sand Beaches in the Maltese Islands

“…On the other hand, other elemental concentrations tend to increase while Sr concentration decreases, proving an inverse relationship. This outcome differs from that obtained by El-Sorogy et al in their coastal sediment analysis performed in Egypt [35], but partly matches previously documented local work undertaken on agricultural soil in Malta [10].…”

“…Similar results have been shown in our previous work undertaken about heavy metal content in agricultural soil in Malta. Links of heavy metal concentrations in the soil to the source of contamination were made, proving both the lithogenic and anthropogenic effects on toxicity concentrations upon their variations according to the plant growth stage [10]. Another study of local Maltese soil contamination by heavy metals proved that all heavy metals studied were present in Marsaxlokk, Qrendi, Gharghur, and Zabbar in Malta and Ghajnsielem in Gozo [11].…”