Vertical Distribution and Chemical Fractionation of Heavy Metals in Dated Sediment Cores from the Saronikos Gulf, Greece

Abstract

The Saronikos Gulf is under a lot of anthropogenic pressure, such as the urban expansion of the metropolitan area of Athens, the port of Piraeus and marinas, industrial activities, and tourism. Heavy metal pollution has been a major environmental problem in the area for many decades. Sedimentary cores have proven to be an invaluable indicator of heavy metal pollution, as they can reveal not only the current metal inputs but also the evolution of pollution over time, and with the appropriate geochemical analyses, they can provide information on the potential toxicity of metals. In this study, the temporal evolution and the chemical speciation of eleven elements were examined in sediment cores from Elefsis Bay and the Inner Saronikos Gulf, with an emphasis on the emerging environmental hazards (V and Ag). The results showed extensive pollution of the sediments by Ni, Cr, Cu, Zn, As, Mo, Cd, and Pb from the 1910s and 1960s in Eastern and Western Elefsis Bay, respectively. A significant decrease of the sediment enrichment in V, Ni, Cr, Cu, Zn, As, Cd, Pb, and Ag since 2000 was observed in the part of the Inner Saronikos Gulf that is mainly influenced by the WWTP of Athens. However, a toxicity assessment using the metal contents of the surface sediments showed that most of the trace elements studied still pose a moderate to high risk of toxicity to benthic ecosystems. The present study highlighted the urgent need for focused research and the management of trace element inputs, particularly Ag in the Inner Saronikos Gulf, where severe sediment modification was evident.

Implementation of a Far-Field Water Quality Model for the Simulation of Trace Elements in an Eastern Mediterranean Coastal Embayment Receiving High Anthropogenic Pressure

“…To compare the predicted values with the actual deposition rates, a comparison was made at stations where field data are available. In Table 3, the modeled sedimentation rates at two stations (S1, S7) are compared with the fluxes calculated based on observed concentrations of trace elements in the sediment [62] and sedimentation rates [63]. Observed concentrations included measurements in nearby areas of each station (west: W; east: E; north: N).…”

“…Table 3. Deposition rates of trace elements at stations S1, S7, and nearby areas: simulated (columns A) and calculated mass fluxes (columns B) based on measured concentrations [62], Table S10, and reported sedimentation rates [63]. Units in mg m −2 year −1 .…”

“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/jmse12050797/s1, Table S1: Sampling Stations network information; Table S2: Analytical table of processes activated in Delft3D-WAQ module for the simulation of ecosystem dynamics; Table S3: Table of processes values, activated in Delft3D-WAQ module, for the simulation of ecosystem dynamics; Table S4: Nutrient loads introduced in the modeling area as discharges; Table S5: Inorganic Matter (IM) average monthly concentration used in the simulations; Figure S1: Perama small-scale industries ship repairing zone, (a) google earth capture, and (b) marine traffic capture; Table S6: Kd time-series table-seasonal values, calculated according to monitoring data [21] and average SS concentrations [42]; Table S7 S8: Statistical analysis of observed vs. modeled concentrations of trace elements; Table S9: Predicted mass of heavy metals reaching the top sediment layer after 365 days of simulation (in mg m−2 year−1); Table S10: Measured concentrations of heavy metals in the top sediment layer (in mg kg −1 ), year 2010, as reported by Karageorgis et al, 2020 [62]; Table S11: Mass fluxes of trace elements (in mg m −2 year −1 ), based on measured concentrations [62] (Table S10) and reported sedimentation rates [63].…”

Toward a Sustainable Blue Economy in the Coastal Zone: Case Study of an Industrialized Coastal Ecosystem in Greece

“…The industrial and maritime activities carried out in the coastal zone of Elefsis Gulf play an important role in the pressures acted in it and gradually degrade its environmental status [37,41]. These industrial and maritime activities are associated with the occurrence of eutrophication phenomena, high rates of hydrocarbons, and heavy metals [41,42]. Moreover, the gulf of Elefsis is a passage for many vessels such as tankers, cargo ships, and cruise ships vessels [43].…”

Metal complexation, FT-IR characterization, and plankton abundance in the marine surface microlayer of coastal areas in the Eastern Mediterranean

“…Differing in terms of their topographical features (depth, occurrence of estuaries) and anthropogenic pressures, the two sites represent different microenvironments. Loutropyrgos site (15-20-m depth) is located close (approximately at a 3-km distance) to the industrial zone (the largest in Greece) of Elefsis Gulf, a relatively shallow embayment (maximum depth 33 m), characterized by a particularly slow water recirculation, enhancing pollution problems observed in the inner part of the gulf (Prifti et al, 2022). The bay is in contact with Saronicos Gulf through two narrow channels at its eastern and western parts.…”