First evaluation of floating microplastics in the Northwestern Adriatic Sea.

Plastic pollution in the marine environment is becoming a problem of global concern, and the Mediterranean is believed to be one of the worst affected regional seas. The present study presents data on floating microplastics in the Northwestern Adriatic Sea in order to evaluate the possible contribution of two significant potential sources: the lagoon of Venice and the Po River. Samples were collected in March and April 2014 along two transects located off Pellestrina Island (Venice) and the Po Delta, each consisting of four sampling stations at 0.5, 3, 10, and 20 km from the shoreline. Microplastics were quantified and classified according to their colors and shapes and analyzed by micro-attenuated total reflection-FT-IR. Microplastics were found in all samples, albeit with high spatial and temporal variability. The highest concentrations were observed in March at the offshore station of the Pellestrina transect (10.4 particles m-2) and the two landward stations off the Po Delta (2.1 and 4.3 particles m-2), highlighting the influence of various factors, such as surface circulation and river discharges, in determining specific accumulation patterns. The most common polymers were polyethylene and polypropylene, and most of the particles were secondary microplastics (83.5%). The patchy distribution of microplastics observed in the study area is driven by hydrodynamic and meteorological factors acting on short time scales.

Imposex levels and butyltin compounds (BTs) in Hexaplex trunculus (Linnaeus, 1758) from the northern Adriatic Sea (Italy): Ecological risk assessment before and after the ban.

The aim of this study was to compare imposex and butyltin compounds (BTs) data, collected before and after the organotin ban in 2008, in order to assess temporal and spatial variation of the phenomenon, the decline of BT contamination, and the effects on Hexaplex trunculus population in the coastal area of the northern Adriatic Sea, close to the Venice Lagoon. Both in marine and in lagoon sites, the results obtained in 2013-2015 showed a significant decline in the incidence of imposex in respect to those from the 2002 survey. In 2002, lagoon samples exhibited Relative Penis Size Index (RPSI) higher than marine samples, whereas no differences were detected in the recent survey, when all RPSI values were below 0.6%. Vas Deference Sequence Index (VDSI) mean values were over 4 before the ban introduction and below this value after that, indicating more critical conditions for gastropod population in 2002 rather than in 2013-15. Percentage of sterile females was up to 69% in 2002, whilst in the more recent survey no sterile female was found. Range of BT concentrations in gastropods decreased from 252 to 579 to 16-31ng∑BT/g d.w. BT body burdens varied according to a gender dependant pattern, with higher concentrations observed in females than in males. A first attempt to propose a classification based on BT impact on H. trunculus, according to the Water Framework Directive, revealed that most sites were in Bad ecological status before the ban and attained a Poor/Moderate status after that.

Biomonitoring of a polluted coastal area (Bay of Muggia, Northern Adriatic Sea): A five-year study using transplanted mussels.

The subcellular effects of pollution were evaluated using two lysosomal biomarkers in mussels, Mytilus galloprovincialis, deployed periodically over a period of 5 years in a harbour area in the Bay of Muggia (Gulf of Trieste, North Adriatic Sea) that is strongly influenced by anthropogenic activities. Mussels were collected from a clean marine farm and analysed (sample T0). A sub-sample was transplanted to the harbour site (sample M) and analysed after about 12 weeks. An additional sub-sample was relocated within the farm as a control and was also tested at the end of the 12-week period (sample T1). The transplantation procedures were repeated twice yearly for 5 consecutive years, starting in 2009. Two well-established lysosomal biomarkers, i.e. lysosomal membrane stability and lipofuscin accumulation, were evaluated in hepatopancreas cells. The body condition index and mortality rate were also assessed. Moreover, various pollutants were determined in both mussel flesh, for a better comprehension of the biological response, and sediments, for a general characterization of the study area. As a whole, the applied biomarkers were found to be appropriate for determining the responses of mussels to environmental pollutant loads over time. Variations in lysosomal membrane stability and lipofuscin content were mostly related to total PAHs and metals respectively. Our results confirm the usefulness of active biomonitoring in evaluating pollution trends in marine coastal areas and in particular the value of lysosomal biomarkers as a rapid screening tool for highlighting pollutant effects at least at organism level.

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.

Biochemical and lysosomal biomarkers in the mussel Mytilus galloprovincialis from the Mar Piccolo of Taranto (Ionian Sea, Southern Italy).

Biomarkers are internationally recognized as useful tools in marine coastal biomonitoring, in particular, as early-warning signals at the level of individual organisms to assess biological effects of pollutants and other stressors. In the present study, Mytilus galloprovincialis has been employed as a sentinel organism to assess biological pollution effects in the Mar Piccolo of Taranto (Southern Italy), a coastal lagoon divided into two small inlets, connected to the open sea through one natural and one artificial narrow openings. Mussels were collected in June 2013 at three sites located within each of the two inlets of the Mar Piccolo. Biological effects were investigated through a suite of biomarkers suitable to reflect effects and/or exposure to contaminants at biochemical and cellular levels. Biochemical biomarkers included glutathione-S-transferase (GST) and acetylcholinesterase (AChE) enzyme activities; as histochemical biomarkers, lysosomal membrane stability, lipofuscin and neutral lipid accumulation, and lysosomal structural changes were considered. As a whole, results highlighted differences among the three study sites, particularly for GST, AChE, and lipofuscins, which are consistent with the variations of the chemical pollutants in sediments. The applied biomarkers showed that a stress syndrome likely to be ascribed to environmental pollutants is occurring in mussels living in the Mar Piccolo of Taranto, in particular, the ones inhabiting the first inlet.

Biomonitoring approach with mussel Mytilus galloprovincialis (Lmk) and clam Ruditapes philippinarum (Adams and Reeve, 1850) in the Lagoon of Venice.

Transplanted Mytilus galloprovincialis and native Ruditapes philippinarum were deployed in 10 sampling stations with different pollution impact within the Lagoon of Venice to evaluate the temporal variations and the suitability of the following cytochemical and histochemical biomarkers just as indicators of environmental stress: lysosomal membrane stability, lipofuscins, neutral lipids and lysosome to cytoplasm volume ratio. The physiological status of the organisms was also investigated by determining the survival in air capability and the reburrowing rate (clams). The biological parameters were assessed in June and October. Furthermore, for a better definition of the environmental aspects of the study sites, heavy metal, PAH and PCB concentrations were also evaluated in the sediments. As a whole, the biological responses examined in both species from all the sampling sites showed significant differences between the two seasonal campaigns, only lysosomal membrane stability exhibited less variability. Pollutants in sediments generally showed low-intermediate contamination levels, few hotspots persisting mostly in the inner areas of the lagoon, the most influenced by the industrial zone. Transplanted mussels were more responsive than native clams and the biological responses of both species varied temporally. The range of the spatial variability was always narrow and reflected only partially the broader variability shown by the chemical content in the sediments. In this sense, biological responses seemed to be particularly influenced by the high temporal and spatial heterogeneity that characterise the Lagoon of Venice, as well as most of the transitional environments.

Seasonal changes in physiological responses and evaluation of "well-being" in the Venus clam Chamelea gallina from the Northern Adriatic Sea.

Chamelea gallina is an infaunal bivalve, widespread in sandy bottoms along Mediterranean coasts. It is an important economic resource for fisheries in the Adriatic, although in recent years over-fishing, and other concurrent factors, have dramatically decreased clam harvesting. In this context, it is of great interest to gain information on seasonal variations in the physiological performance of clams, for an overall evaluation of their well-being. In this study, laboratory experiments were performed to define allometric relationships and effects of temperature on clearance and respiration rates of C. gallina. The mean values of b coefficients were calculated and used to correlate physiological measurements to 'standard' body mass, when seasonally collected clams were analysed. The highest clearance rate (0.42 L h(-1)) was measured in clams collected in July 2000; the highest respiration rate (12.22 micromol O2 h(-1)) was observed in July 2001, leading to a negative scope for growth (-2.8 J h(-1)). The influence of environmental and endogenous factors, mostly reproduction, was discussed. Survival in air and condition indices, showing higher stress conditions in December 2000 and July 2001, were in good agreement with the other physiological measurements. The physiological responses examined in this study appear to be suitable for providing detailed indications on the well-being of C. gallina and may be useful for future studies aimed at eco-sustainable management of the resource.

Concentrations of organotin compounds and imposex in the gastropod Hexaplex trunculus from the Lagoon of Venice.

In four stations located close to the channels connecting the Lagoon of Venice with the Adriatic Sea (two inside the lagoon and two outside it), individuals of Hexaplex trunculus were collected in order to assess their contamination. Concentrations of some organotin compounds, i.e. tributyltin and triphenyltin with their di- and mono- substituted metabolites, were measured and endocrine disruption such as imposex (superimposition of male sexual characteristics on females of gonochoristic gastropods) was observed. Vas deferens sequence indexes (VDSI) of 4.1-4.9 were found in organisms from stations inside the lagoon, and 3.6-4.2 in the sea stations. Organotin derivatives were measured in both the visceral coil and the rest of the soft body of the organisms. Total concentrations of butyltin compounds ranged from 102 +/- 17 to 432 +/- 27 ng Sn g(-1) d.w. in the visceral coil, and from 96 +/- 24 to 297 +/- 107 ng Sn g(-1) d.w. in the rest of the soft body. Phenyltins were found at far lower concentrations, ranging from 8 +/- 1 to 41 +/- 3 ng Sn g(-1) d.w. (visceral coil) and from 0.25 to 32 +/- 22 ng Sn g(-1) d.w. (rest of soft body). The degree of imposex in female gastropods, evaluated from VDSI and penis lengths, was related to organotin contents in the soft body. In particular, female penis lengths were significantly correlated (r = 0.917 and r = 0.982, P<0.05) to tributyltin (TBT) contents and the sum of organotin compounds in organisms.

Evaluation of 4-nonylphenol toxicity in the clam Tapes philippinarum.

Lethal and sublethal effects of 4-nonylphenol (NP) were investigated in the clam Tapes philippinarum from the Lagoon of Venice. In a 96-h lethality test, bivalves were exposed to the following NP concentrations: 0, 0+acetone, 0.19, 0.38, 0.75, 1.5, and 3.0mg NP/L. The 96-h LC(50) value was 1.12mg NP/L. No mortality was observed at 0.19mg NP/L, whereas at 1.5 and 3.0mg NP/L both siphons and foot of clams were often cut-off, the animals being unable to withdraw them before shell closure, suggesting the possible narcotic effect of NP. Lower concentrations (0, 0+acetone, 0.025, 0.05, 0.1, and 0.2mg NP/L) were then used to evaluate sublethal NP effects on clearance rate (CR), respiration rate (RR), scope for growth (SFG), and survival in air. Following a 7-day exposure, decreased RRs were found at all NP concentrations tested. Significant decreases in the CR and SFG were only observed at the two highest NP concentrations (0.1 and 0.2mg/L), with SFG reductions reaching 54% and 71%, respectively. Last, the highest concentrations tested significantly decreased the resistance of clams to exposure to air and enhanced the mortality rate. As the lowest effective NP concentrations are similar to environmentally realistic levels, a condition of potential risk for the well-being of clam populations in estuarine areas is highlighted.