Geochemistry of major and trace elements in surface sediments of the Saronikos Gulf (Greece): Assessment of contamination between 1999 and 2018.

The Saronikos Gulf receives pressures from the most urbanized and industrialized areas in Greece, the Athens metropolitan area and Pireaus port, and as such, it is considered as a hot spot of pollution in the Eastern Mediterranean Sea. Decades after policies aiming to achieve clean seas have been introduced and implemented, it is currently relevant to evaluate their impact on the environmental quality. Here we propose a methodology for this topical issue and we assess the distribution of major and trace elements using a 20 year (1999-2018) sedimentary record, and determine the current status, as well as contamination trends. The proposed synthesis of methods is outlined by the following major steps: establishment of background levels from dated cores, calculation of Enrichment Factors (EFs) and the multi-elemental, Modified Pollution Index (MPI), and assessment of temporal trends of MPI in a sub-regional scale. Copper, Zn, and Pb exhibited the highest EFs, mostly observed in the Elefsis Bay, the Inner sector of the Gulf, and the area parallel to the western Attica coast. The MPI classified the latter areas as moderately-heavily to severely polluted. Decreasing trends were detected in the industrialized Elefsis Bay, and were attributed to the decrease of land-based metal loads. No trends were detected in the other sub-regions, highlighting the need for intensifying efforts to abate pollution by designing management plans towards the reduction of metal contamination in the Saronikos Gulf. Finally, the present study illustrates that multi, regionalized background levels are necessary for effectively resolving elemental variations, particularly in the presence of metal-rich lithological complexes within the catchment areas. This finding should be taken into account when the background levels and background assessment levels are established for the Eastern Mediterranean's sub-regional seas within the framework and implementation of the EU's Marine Strategy Framework Directive.

Can we document if regulation and Best Available Techniques (BAT) have any positive impact on the marine environment? A case based on a steel mill in Greece.

In order to document the impact of Best Available Techniques (BAT) and implementation of regulation on the improvement of the coastal marine environment state, we examined the case of a representative steel mill located at the Gulf of Elefsis (Greece). The evaluation of metal pollution was based on the analysis of major and trace elements, organic carbon, magnetic properties, and sediment accumulation rates, in sediment cores obtained from the vicinity of the plant. The analytical data are discussed in relation to steel production, changes of production routes, and adoption of BAT introduced in order to fulfill EU and national legislation. The results show that the input of pollutants to sediments and the degree of contamination were reduced by approximately 40-70% in the decade 2003-2015 in comparison to the periods of high discharges (1963-2002), whereas the toxicity risks from "high-to-extremely high" were reduced to "medium-to-high."

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas: The PERSEUS experience.

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES.

Pseudomonas, Pantoea and Cupriavidus isolates induce calcium carbonate precipitation for biorestoration of ornamental stone.

AIMS: Bacterially induced calcium carbonate precipitation from various isolates was investigated aiming at developing an environmentally friendly technique for ornamental stone protection and restoration. METHODS AND RESULTS: Micro-organisms isolated from stone samples and identified using 16S rDNA and biochemical tests promoted calcium carbonate precipitation in solid and novel liquid growth media. Biomineral morphology was studied on marble samples with scanning electron microscopy. Most isolates demonstrated specimen weight increase, covering partially or even completely the marble surfaces mainly with vaterite. The conditions under which vaterite precipitated and its stability throughout the experimental runs are presented. CONCLUSIONS: A growth medium that facilitated bacterial growth of different species and promoted biomineralization was formulated. Most isolates induced biomineralization of CaCO3 . Micro-organisms may actually be a milestone in the investigation of vaterite formation facilitating our understanding of geomicrobiological interactions. Pseudomonas, Pantoea and Cupriavidus strains could be candidates for bioconsolidation of ornamental stone protection. SIGNIFICANCE AND IMPACT OF THE STUDY: Characterization of biomineralization capacity of different bacterial species improves understanding of the bacterially induced mineralization processes and enriches the list of candidates for biorestoration applications. Knowledge of biomineral morphology assists in differentiating mineral from biologically induced precipitates.

Assessment of heavy metal contamination and mineral magnetic characterization of the Asopos River sediments (Central Greece).

The content and distribution of heavy metals in sediments of the intermittent and contaminated Asopos River, located in Central Greece, was assessed by means of total dissolution, dilute acid and sequential extraction procedures. Mineral magnetic properties were used as proxy parameters of transport mechanisms of land-derived material to the sea. The combination of enrichment factors estimated against local background levels and the levels of labile metals revealed that surface sediments are enriched in Cu, Cd, Ni and Cr. The low flow of the system allows particles and organic matter to accumulate in the estuarine shallow "pools" where they undertake a series of redox reactions, authigenic formation, etc. The most fine of these particles, which are metal rich, are transported to relatively long distances off the Asopos River mouth, even under low energy conditions, converting the system to a secondary source of pollution for the adjacent marine environment.

Underwater in situ measurements of radionuclides in selected submarine groundwater springs, Mediterranean Sea.

The application of the in situ measurement system 'KATERINA' for monitoring of radon progenies in submarine groundwater discharge (SGD) was investigated at different locations in the Mediterranean Sea (Chalkida, Stoupa, Korfos and Cabbé). At Chalkida and Stoupa radon progenies concentration exhibited almost constant values of 1.2 ± 0.1 and 2.5 ± 0.2 Bq l(-1), respectively. At Korfos these activities ranged between 1.4 ± 0.1 and 2.3 ± 0.2 Bq l(-1) exhibiting inverse relationship with salinity. At Cabbé the in situ measured data were compared with radon measurements obtained by liquid scintillation counter. The system also resolved radon progeny variations of SGD on time scales above 1 h. The radioactivity levels of radon progenies from all sites were found considerably lower (approximately 2 orders of magnitude) than the commonly accepted limits for radon in drinking water.