An ecotoxicological approach to evaluate the effects of tourism impacts in the Marine Protected Area of La Maddalena (Sardinia, Italy).

In the Marine Protected Area of La Maddalena Archipelago, environmental protection rules and safeguard measures for nautical activities have helped in reducing anthropogenic pressure; however, tourism related activities remain particularly significant in summer. With the aim of evaluating their impacts, the biomarker approach using transplanted Mytilus galloprovincialis as sentinel organisms coupled with POCIS deployment was applied. Mussels, translocated to four marine areas differently impacted by tourism activities, were sampled before, during and after the tourist season. Moreover, endocrine disruptors in passive samplers POCIS and the cellular toxicity of whole POCIS extracts on mussel haemocytes were evaluated to integrate ecotoxicological information. Lysosomal biomarkers, condition index and mortality rate, as well as metals in tissues suggested an alteration of the health status of mussels transplanted to the most impacted sites. The cellular toxicity of POCIS extracts was pointed out, notwithstanding the concentrations of the examined compounds were always below the detection limits.

A preliminary investigation on nanohorn toxicity in marine mussels and polychaetes.

Single walled carbon nanohorns (SWCNHs) are a black nanoscale spherical aggregate of cylindrical tubes of graphitic carbon which differ from nanotubes in their "horn-like" shape. Their peculiar structure makes them one of the best electronconductors at a nanoscale level. Although not commercially exploited, their rapid environmental diffusion is expected to rise significantly in the next few years. Therefore, we appraised the ecotoxicology of SWCNH powders by taking into account the ecological role of the two species that were deployed in exposure experiments: polychaetes, Hediste diversicolor, and mussels, Mytilus galloprovincialis. Adult mussels and polychaetes were exposed to three SWCNH concentrations: 1, 5, and 10 mg L(-1) and acute effects were measured after 24 and 48 h. Sub-lethal effects were estimated at level of physiological functions such as digestion in mussels (i.e. variations in lysosomal parameters and lipofuscin content) and the antioxidant system in both species (i.e. glutathione peroxidase activity and malondialdehyde content). SWCNH suspension in sea water was also characterised, highlighting the formation of aggregates the size of which was related to SWCNH concentrations and their resident time in the medium. The results showed that SWCNH affected the oxidative and lysosomal systems on the hepatopancreas and led to lysosomal alterations on haemocytes in mussels. The biological responses were less clear in polychaetes. This preliminary investigation highlighted the need of focusing future research efforts on possible physiological impairments caused by long-term exposure to SWCNHs in marine species.

Is the polychaete, Perinereis rullieri (Pilato 1974), a reliable indicator of PCB and PAH contaminants in coastal sediments?

A field survey in a transitional environment (lagoon of Venice, Italy) and a laboratory exposure experiment were carried out to validate the use of polychaetes, Perinereis rullieri, as indicators of PCB and PAH contaminants in the sediments. Results from the field study showed that PCBs, predominantly the hexa- and hepta-chlorinated biphenyls, were promptly bioaccumulated in the tissues of P. rullieri, whereas PAH levels were generally low and fluctuating among seasons. Organisms experimentally exposed to natural polluted sediments bioaccumulated all the examined PCB congeners, whereas those exposed to the reference sediments were able to reduce them, at least to some extent. A PAH depletion was always observed, although the time variations for the single compounds differed from each other. The biomarker malondialdehyde (MDA), evaluated both in native and in treated organisms, was helpful as a supporting parameter in elucidating their oxidative stress condition, although depending on numerous natural confounding factors.

Bioaccumulation and biomarker responses of trace metals and micro-organic pollutants in mussels and fish from the Lagoon of Venice, Italy.

The aims of this study were to evaluate levels and effects of trace metals (Cd, Cr, Cu, Fe, Mn, Pb, Zn), PAHs and PCBs in mussels and fish native to the Lagoon of Venice. To this end, bioaccumulation and various biomarkers of generic stress and exposure (malondialdehyde, MDA and metallothioneins, MT; ethoxyresorufin O-deethylase activity, EROD; fluorescent bile metabolites and somatic indices in fish; lysosomal membrane stability, LMS; lipofuscins, LF; neutral lipids, NL and survival-in-air, SOS in mussels) were measured in organisms seasonally collected from two differently influenced areas. In mussels, metal bioaccumulation levels at the two sites were low and fluctuated similarly, exhibiting decreasing levels in summer, like MDA and MT. Micro-organic pollutants and the probably related biological response of LMS did not show either significant site differences or seasonal trends. LF and NL revealed inconclusive patterns. The results of the survival-in-air test were quite erratic, showing that they were associated with the high variability of both natural and physiological parameters temperature, food, reproduction, and body reserve cycle. In fish, both inorganic and organic micropollutant levels were low, and differences were detected between sites only for PCBs. The pattern exhibited by micro-organic contaminants was clearly related to the reproductive cycle at both sites; a relationship with PCBs, EROD and MDA was established at the site where their levels were generally higher. Bile metabolites (3-OH benzo(a)pyrene, 1-OH pyrene) were associated with PAH contents.

Cellular alterations in Mytilus galloprovincialis (LMK) and Tapes philippinarum (Adams and Reeve, 1850) as biomarkers of environmental stress: field studies in the Lagoon of Venice (Italy).

A long-term biomonitoring study was carried out in the Lagoon of Venice (North-East Italy) with the aim of evaluating variations in biological responses to environmental stress in estuarine bivalves. Two different species, the mussel Mytilus galloprovincialis and the clam Tapes philippinarum, both widespread in the Lagoon, were studied in several sites. Two cellular biomarkers: lysosomal membrane stability in digestive cells and thickness of digestive epithelia, were evaluated in native organisms (on a seasonal basis), and in organisms which have been transferred from a reference site to several differently influenced ones. Results indicate that, to some extent, both test and organisms were able to highlight site-specific differences, but the effects of pollution were generally more easily detected by reduction in lysosomal stability than by reduction in digestive tubule epithelium. Further findings show that the inherent variability of a number of natural parameters, particularly in the reference sites, produced less effective results when biological responses in the reference organisms were compared with the polluted ones. The assessment of the two conditions was most valuable when they referred to the 25-75% range of values comprised within the seasonal medians, recorded respectively in control and polluted sites. Impaired from steady states were most effectively distinguished when the control values were medians from two reference locations. Lately, the overall results indicate that both biomarkers are more suitably deployed through the translocation approach, revealing it to be more sensitive than traditional biomonitoring, at least in the sense that it may overcome problems related to the adaptation of native organisms to sub lethal chronic pollution levels.

Field application of biochemical markers and a physiological index in the mussel, Mytilus galloprovincialis: transplantation and biomonitoring studies in the lagoon of Venice (NE Italy).

A number of biochemical markers and a physiological index were measured in mussels, Mytilus galloprovincialis, transplanted or native to five different contaminated sites in the lagoon of Venice. Mussels from Pellestrina, a reference site in the adjacent Adriatic Sea, were transplanted for 6 weeks to areas of the lagoon where indigenous mussels were also collected. As biochemical indices, superoxide dismutase (SOD), catalase, aldehyde dehydrogenase (ADH) and NADPH cytochrome c reductase (NADPHcred) were measured in mussel digestive gland; survival in air as a physiological index was also determined. Biomarker responses varied among sites and between indigenous and transplanted animals. Significant induction of catalase and SOD was shown in animals transplanted to the urban sites of Salute and Chioggia, respectively. In indigenous mussels, induction of SOD and NADPHcred was seen in animals from the polluted site of Treporti and the heavily contaminated industrial area of Marghera. The overall biochemical data indicate significantly higher activity for ADH in transplanted animals in comparison with indigenous ones which, in contrast, present an increase in SOD. As regard survival in air, control mussels did not seem to be healthier in comparison either with transplanted or indigenous ones, suggesting that pollution has no effect on this parameter.

Biochemical and histochemical responses to environmental contaminants in clam, Tapes philippinarum, transplanted to different polluted areas of Venice Lagoon, Italy.

In this study the clam, Tapes philippinarum, a filter-feeding bivalve living in soft bottoms, was used to investigate the water/sediment pollution in Venice Lagoon (Venice, Italy), a heavily urbanised and industrialised area. To this end, clams collected from indigenous populations in a clean farming area (Val Dogà) were transplanted into a relatively low contaminated site (Palude della Rosa) and in a heavily polluted area (Porto Marghera), for 5 weeks. A range of possible induced stress indices were measured, on the basis of potential toxicity mechanisms, including specific enzymatic activities [Bap hydroxylase and NADPH cytochrome c reductase, superoxide dismutase, catalase, glutathione peroxidase and propionaldehyde dehydrogenase (PDH)] and general cellular responses (lysosomal latency). Moreover, chemical analyses (polychlorinated biphenyls, polycyclic aromatic hydrocarbon, DDTs) were carried out on sediments and animal tissues at the beginning and end of the transplantation experiments. The chemical results show an active bio-accumulation activity from sediment in clams translocated to the most polluted area. Correspondingly, biological data indicate marked effects on PDH activity and latency in T. philippinarum from the same site. In contrast, no similar pattern has been observed in the other considered indices, possibly due to antagonistic effects of the complex contaminant mixture present in the environment.