Loggerhead sea turtles (Caretta caretta): A target species for monitoring litter ingested by marine organisms in the Mediterranean Sea.

Marine litter is any persistent, manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal environment. Ingestion of marine litter can have lethal and sub-lethal effects on wildlife that accidentally ingests it, and sea turtles are particularly susceptible to this threat. The European Commission drafted the 2008/56/EC Marine Strategy Framework Directive with the aim to achieve a Good Environmental Status (GES), and the loggerhead sea turtle (Caretta caretta, Linnaeus 1758) was selected for monitoring the amount and composition of litter ingested by marine animals. An analogous decision has been made under the UNEP/MAP Barcelona Convention for the protection of the Mediterranean Sea, following the Ecosystem Approach. This work provides for the first time, two possible scenarios for the Marine Strategy Framework Directive GES, both related to "Trends in the amount and composition of litter ingested by marine animals" in the Mediterranean Sea. The study validates the use of the loggerhead turtle as target indicator for monitoring the impact of litter on marine biota and calls for immediate use of this protocol throughout the Mediterranean basin and European Region. Both GES scenarios are relevant worldwide, where sea turtles and marine litter are present, for measuring the impact of ingested plastics and developing policy strategies to reduce it. In the period between 2011 and 2014, 150 loggerhead sea turtles, found dead, were collected from the Italian Coast, West Mediterranean Sea Sub-Region. The presence of marine litter was investigated using a standardized protocol for necropsies and lab analysis. The collected items were subdivided into 4 main categories, namely, IND-Industrial plastic, USE-User plastic, RUB-Non plastic rubbish, POL-Pollutants and 14 sub-categories, to detect local diversity. Eighty-five percent of the individuals considered (n = 120) were found to have ingested an average of 1.3 ± 0.2 g of litter (dry mass) or 16 ± 3 items.

Environmental hazard of yperite released at sea: sublethal toxic effects on fish.

The aim of this study was to evaluate the potential toxicological effects on fish related to the leakage of yperite from rusted bomb shells dumped at sea. Both in vivo and field studies have been performed. As for the in vivo experiment, specimen of European eel were subcutaneously injected with 0.015, 0.15 and 1.5mg/kg of yperite and sacrificed after 24 and 48 h. In the field study, specimen of Conger eel were collected from a dumping site in the Southern Adriatic Sea. The presence/absence of yperite in tissues, genotoxicity, detoxification enzymes, histological alterations and gross abnormalities were investigated. Results of the in vivo experiment showed a significant increase of EROD activity at both 24h and 48 h. UGT activity increased significantly at 48 h post injection. An acute inflammatory response after 24h in skin layers and muscle was observed, associated to cell degeneration and necrosis after 48 h at the highest dose. On field, comet assay revealed genotoxicity in gills of fish from the dumping site. Specimen from the dumping site showed significantly higher EROD activities compared to controls, deep ulcers and papules on skin together with liver and spleen histopathological lesions.

Modulation of CYP1A and genotoxic effects in European seabass (Dicentrarchus labrax) exposed to weathered oil: a mesocosm study.

The aim of this study was to assess medium-term toxicity of weathered oil on European seabass. A mesocosm system reproducing an oil spill at sea was applied. Fish were collected after 48 h, 7, 30 and 60 days. Cyp1a gene transcription, EROD and UDPGT activities, bile PAHs metabolites and micronuclei frequency were investigated. A progressive disappearance of low molecular weight n-alkanes and PAHs in the water of the mesocosm occurred during the experimentation. Fishes exposed to oil displayed a significant increase of cyp1a expression and EROD activity during the entire experiment as well as higher concentrations of PAHs metabolites in bile. Micronulei frequency resulted significantly higher during all experiment in oil exposed sea bass compared to controls. The results highlight the environmental risk associated with the release of oil products at sea and confirm the adopted parameters as useful tools for studying the impact of accidental oil spills on fish.

DNA damage, severe organ lesions and high muscle levels of As and Hg in two benthic fish species from a chemical warfare agent dumping site in the Mediterranean Sea.

The aim of the present study was to evaluate the environmental threat to benthic species from chemical weapons dumped in the southern Adriatic Sea. An ecotoxicological approach using chemical analysis and biological responses was applied, in two sentinel species: the Blackbelly rosefish Helicolenus dactylopterus and European conger Conger conger. Specimen were collected in a stretch of sea, where had been dumped war materials and from a reference site free of ordnance. Residues of yperite, Hg and As were measured in fish fillets. Skin, liver, kidney and spleen were examined for histopathological and macroscopical lesions. Liver detoxifying capacities (EROD and UDPGT) and genotoxicity (comet assay) were also investigated. As and Hg levels were three-four times higher than those from the reference site in both species (p<0.001). Both species captured in dumping site showed clear signs of chronic illness according to the health assessment index (HAI). Deep ulcers and nodules were observed on skin and external organs. Histological lesions such as periportal and bile duct fibrosis, pericholangitis, steatosis, granuloma and elevated splenic MMCs were detected in liver and spleen. Significantly higher EROD activities were also found in both species from dumping site (p<0.01). Comet assay revealed genotoxicty in gills of C. conger from dumping site, indicating uptake of chemical warfare agents through fish gills. European conger was found to be a more sensitive bioindicator of this type of contamination than the Blackbelly rosefish.

Effects of 2,4,6-trinitrotoluene (TNT) on phase I and phase II biotransformation enzymes in European eel Anguilla anguilla (Linnaeus, 1758).

The aim of this study was to investigate effects of the explosive 2,4,6-trinitrotoluene (TNT) on liver drug metabolizing genes and enzymes in the European eel Anguilla anguilla as a model fish species. Eels were exposed in vivo for 6h and 24h to 0.5, 1 and 2.5mg/L nominal concentrations of TNT. Expression of CYP1A, glutathione-S-transferase (pi-class; GST) and uridine-diphosphate glucuronosyltransferase (1-family) (UDPGT) genes was investigated by RT-PCR, and 7-ethoxy- and 7-methoxyresorufin-O-dealkylases (EROD, MROD), NADPH cyt c reductase (NADPH red), UDPGT and GST enzyme activities were measured by biochemical assays. An in vitro study was also performed, measuring only EROD activity. TNT exposure produced no modulation of CYP1A transcript expression while a significant inhibition of EROD enzyme activity was observed and confirmed in vitro. UDPGT transcript increased dose-dependently only at 6h while the UDPGT activity tended to increase dose-dependently at 24h. GST gene expression increased after 24h and significant increases of GST activity were observed both at 6 and 24h only at the highest TNT concentration. An increase of NADPH red activity was observed at 24h. Our results seem to indicate an inhibitory effect of TNT on CYP1A-dependent catalytic activities and a possible involvement of phase II enzymes as well as NADPH red in TNT metabolism in eels.