Trace metals in the marine surface microlayer of coastal areas in the Aegean sea, Eastern Mediterranean

Concentrations of 10 trace metals were determined seasonally in the sea surface microlayer (SML) and sub-surface water (SSW) at coastal areas of the Aegean sea comprising different morphological characteristics and degrees of pollution. Metal concentrations varied broadly, specifically in the SML, being typical of coastal areas subject to intense anthropogenic pressures. The mean enrichment factors (EFs) for dissolved metals range from 1.7 (for V) to 3.6 (Zn), being lower than the corresponding calculated for suspended particulate metals ranging from 2.4 (Cd) to 17 (Cr). A statistically significant enrichment of the SML (greater than unity) was obtained for dissolved metals following the decreasing order Zeta n, Cu, Mn, Pb, Fe, Co, Cr, Ni, however not for Cd and V, and in the suspended particulate matter for Cr, Cu, Pb, Ni, V, Zn, Cd, Mn, while not for Fe. Surface microlayer enrichment in metals is governed by complex physicochemical and biological processes, occurring in coastal areas, among which the continuous precipitation of atmospheric particles onto the sea surface and the processes of metals dissolution and partitioning. Correlations among the trace metals examined, the sites sampled and the factor of seasonality are also discussed.

Automated summary

Seasonal variations in concentrations of trace metals were observed in the sea surface microlayer and sub-surface water in coastal areas of the Aegean sea, with metal enrichment factors differing between dissolved and suspended particulate metals. The enrichment of metals in the surface microlayer is governed by complex physicochemical and biological processes, influenced by factors such as atmospheric deposition and metal dissolution.