Metal and metallothionein concentrations in mesozooplankton from an oligotrophic offshore area in the eastern Mediterranean Sea (Cretan Passage/Levantine Sea).

Spatial variability of Cd, Cu, Cr, Ni, Zn, Fe, Mn, Pb and metallothionein (MT) concentrations were determined in mesozooplankton samples along the west-east axis of the Cretan Passage in the western Levantine Sea (Eastern Mediterranean). Metal and MT values from the present study are proposed as background levels, due to the lack of substantial anthropogenic activities in the area, where only maritime traffic and atmospheric deposition could be potential sources. Higher concentrations, of both metals and MTs, were recorded mainly at the western stations indicating higher metal bioavailability than in the eastern part. An inverse relationship of the metal zooplankton levels with zooplankton biomass, abundance and vital rates (production, respiration and ingestion rates), as well as salinity, was evident. We discuss the hypothesis that physical and biological characteristics of the marine environment, affecting growth dynamics of phytoplankton and zooplankton communities, may also act on metal uptake in oligotrophic marine systems.

Metal and metallothionein levels in zooplankton in relation to environmental exposure: spatial and temporal variability (Saronikos Gulf, Greece).

Metal and metallothionein (MT) in mixed zooplankton were investigated as means of monitoring metal availability regarding environmental exposure. Spatial and temporal variability of Cd, Cu, Ni, Zn, Fe, Mn and Pb in zooplankton and seawater were studied in Saronikos Gulf (Aegean Sea, Eastern Mediterranean), once every second month during an annual cycle (2011-2012). Particulate organic carbon and chlorophyll α were also measured in seawater samples. Median zooplankton metal concentrations were 0.65, 32.4, 7.1, 864, 1420, 40.2 and 26.8 µg g-1 dw for Cd, Cu, Ni, Zn, Fe, Mn and Pb, respectively, and 109 µg g-1 ww for MTs. Metal levels in zooplankton and MTs were higher at sites influenced by human-derived pressures. Additionally, metal concentrations in pelagic fish flesh from the Greek MED-POL data base were used for bioconcentration and biomagnification factors calculation. Bioconcentration from water to zooplankton was higher than metal transfer from either seston to zooplankton or zooplankton to fish.

Biological and biochemical assessment in Phorcus articulatus (Lamarck 1822): contamination and seasonal effect.

This work aims to diagnose the state of the northeastern coasts of Tunisia using P. articulatus species. Biological parameters, protein and metallothionein content, enzymatic activities, and metallic concentration were assessed at four stations during four seasons and analyzed by multiple regressions. The comparison of biological ratios showed minima at Sidi Daoued and maxima at Korbous where metallothioneins were maximal. The catalytic activity was low during summer and higher during cold periods contrary to acetylcholinesterase activity. Concerning glutathione S-transferase, its activity was important at Kelibia in autumn and at La Goulette and Sidi Daoued in warm seasons. The metallic concentrations were low at Korbous and maximal at Kelibia and Sidi Daoued stations. Kelibia seems to be the most polluted site followed by Sidi Daoued and La Goulette (industries, urbanization and fishing ports). The pollution seems to be reduced at Korbous station having more suitable conditions for the proliferation of monodonts.

Bio-monitoring of metal impact on metallothioneins levels in the gastropod Phorcus turbinatus (Born, 1778) in the northeastern and the eastern coasts of Tunisia.

This work is an evaluation of metal contamination degree in Phorcus turbinatus and a monitoring of metals impact on metallothioneins functioning. The gastropod was sampled from six stations along the northeastern and eastern coasts of Tunisia during four seasons (2014-2015). Our results suggested that sedimentological metallic contents (Copper, Zinc and Cadmium) vary significantly depending on stations and not significantly according to seasons except for copper. Nevertheless, differences were no significant between stations and significant between seasons as for ambient factors, metallic intrinsic contents and metallothioneins rates. The monodonta tissue seems to be enriched in the four analyzed metals (Cu, Zn, Cd and Hg) and this species seems to have an ability to accumulate metals. Metal effect on the protein induction may be linked to physicochemical factors (temperature, O2 and Cu contents in sediment). In fact, metallothioneins levels were positively correlated to the dissolved oxygen rates and negatively linked to temperature.

Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea.

Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the "Integrated Biological Responses version 2" index was useful for the interpretation of overall biomarker responses.

Metal and metallothionein concentrations in Paracentrotus lividus from Amvrakikos gulf (Ionian Sea-Greece).

Concentrations of Cd, Cu, Cr, Ni, Zn, Fe and metallothioneins (MTs) were measured in the gonads of Paracentrotus lividus from Amvrakikos gulf (Ionian Sea, Greece). Three natural populations were selected; two of them, growing inside the gulf (Agios Thomas and Koronisia), presented higher density and smaller body size than the population living in a coastal area just outside the gulf (Mytikas). Metal and MT levels were not elevated, with the exception of Zn, showing high values related to the reproduction stage of the sea urchins. Significant geographical variations were recorded in the concentrations of Cu, Zn, Cd, Cr and MTs. The highest mean and maximum values of Cu, Zn and MTs were recorded in Agios Thomas while Cd and Cr were higher in Mytikas population. Copper, Zn, Fe and MT concentrations were negatively correlated to the sea urchin body size, while a positive concentration-size relationship was observed for Cd. Although all studied populations grow in a low metal level marine environment, urchins with smaller body size living in a food limited marine environment showed higher gonadosomatic index, metal concentrations and MT levels in their gonads (Agios Thomas and Koronisia) than larger specimens growing in a food unlimited area (Mytikas).

Impact of dredged urban river sediment on a Saronikos Gulf dumping site (Eastern Mediterranean): sediment toxicity, contaminant levels, and biomarkers in caged mussels.

Impacts of chemical contaminants associated with dumping of dredged urban river sediments at a coastal disposal area in Saronikos Gulf (Eastern Mediterranean) were investigated through a combined approach of sediment toxicity testing and active biomonitoring with caged mussels. Chemical analyses of aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), Cu, and Zn in combination with the solid phase Microtox® test were performed on sediments. Concentrations of PAHs, AHs, Cu, and Zn as well as multiple biomarkers of contaminant exposure and/or effects were measured in caged mussels. Sediments in the disposal and neighboring area showed elevated PAHs and AHs concentrations and were characterized as toxic by the solid-phase Microtox® test during and after dumping operations. Biomarker results in the caged mussels indicated sublethal effects mainly during dumping operations, concomitantly with high concentrations of PAHs and AHs in the caged mussel tissues. Cu and Zn concentrations in sediments and caged mussels were generally not elevated except for sediments at the site in the disposal area that received the major amount of dredges. High PAHs and AHs levels as well as sublethal effects in the caged mussels were not persistent after termination of operations. The combined bioassay-biomarker approach proved useful for detecting toxicological impacts of dredged river sediment disposal in sediments and the water column. Nevertheless, further research is needed to evaluate whether sediment toxicity will have long-term effects on benthic communities of the disposal area.

Metal concentrations and metallothionein levels in Mytilus galloprovincialis from Elefsis bay (Saronikos gulf, Greece).

Spatial and temporal variability of Cd, Cu, Cr, Ni, Zn, Fe and Mn and metallothionein (MT) concentrations were determined in mussels Mytilus galloprovincialis from Elefsis bay (Saronikos gulf, Greece). Higher concentrations of both metal concentrations and MTs were recorded in mussels inhabiting industrial locations (steelworks and shipyard), indicating a markedly higher metal bioavailability. However at these sites, located at the eastern part of the bay, mussel metal concentrations were not always correlated with both seawater metal concentrations and MTs possibly due to different time scales of integration of the metal sources into mussels and/or the participation of other metal regulatory mechanisms except MT induction. The pattern of the temporal variation of mussel metal concentrations and the MT levels was similar among stations with higher values during the winter-spring season and lower during the summer-autumn period. The inverse relationship of flesh condition index with mussel metal concentrations was attributed to the influence of mussel annual reproductive cycle.

Active biomonitoring in Greek coastal waters: application of the integrated biomarker response index in relation to contaminant levels in caged mussels.

An integrated approach using biomarkers and contaminant levels in mussels Mytilus galloprovincialis L. was employed to assess chemical contamination in Greek coastal waters within the framework of the MYTIMED program. Biomarkers (metallothioneins, glutathione S-transferase, catalase, acetylcholinesterase and RNA:DNA ratio) have been previously described in mussels caged at 14 sites in coastal areas influenced by different types of anthropogenic activities. This study applied a biomarker index, the Integrated Biomarker Response (IBR) to summarize biomarker responses and relate stress levels to concentrations of organochlorine compounds (PCBs, DDTs), polycyclic aromatic hydrocarbons (PAHs), and metals (Cu, Ni, Fe, Zn) measured in the mussel tissues. The IBR index indicated environmental stress at sites near cities and industries and was overall related to organic contaminants, but also elevated metal concentrations at certain sites. Slightly increased IBR values at few sites away from known pollution sources were not accompanied with increased contaminant levels suggesting stress possibly caused by natural factors. Results confirmed the usefulness of integration of biological effects measurements and chemical analysis for the assessment of chemical contamination in coastal waters.