Porto Marghera Research Articles

A multibiomarker approach in clams (Ruditapes philippinarum) for a toxicological evaluation of dredged sediments

The Lagoon of Venice is often dredged for channel maintenance. To avoid harmful consequences to the ecosystem, a proper disposal of bottom sediments requires a preliminary evaluation of its potential toxicity before excavation. Here we evaluated the effects of polluted sediments on clams (Ruditapes philippinarum) using a multibiomarker approach. Bivalves were exposed for 3 and 14 days to five sediment samples collected along a navigation canal between Venice historical centre and the industrial area of Porto Marghera. Immunological, antioxidant, detoxification, and neurotoxicity biomarkers were analysed in haemolymph, gill, and digestive gland. As a control, sediment collected far from pollution sources was used. Two experiments were performed to assess potential seasonal/gametogenic influence in clam sensitivity. A different response of clam biomarkers was observed during the two experiments and among sampling sites. Clams’ digestive gland resulted to be the most sensitive tissue analysed showing significant differences among sites in all biomarkers analysed. Greater differences were present due to seasonality rather than exposure. The concentrations of metals and organic pollutants increased from the city centre to the industrial area, highlighting the influence that industrial activities had on the lagoon ecosystem. However, bioaccumulation in clams did not follow the same clear pattern, suggesting low bioavailability of compounds due to relatively high organic matter content. Biomarkers modulation was mainly driven by metals, both present in sediments and bioaccumulated. In comparison, effects of organic pollutants on the biomarkers tested were negligible. Other sources of contamination not investigated (e.g. pesticides) were suggested by neurotoxicity biomarkers alteration.

Contaminants from dredged sediments alter the transcriptome of Manila clam and induce shifts in microbiota composition

BackgroundThe reuse of dredged sediments in ports and lagoons is a big issue as it should not affect the quality and the equilibrium of ecosystems. In the lagoon of Venice, sediment management is of crucial importance as sediments are often utilized to built-up structures necessary to limit erosion. However, the impact of sediment reuse on organisms inhabiting this delicate area is poorly known. The Manila clam is a filter-feeding species of high economic and ecological value for the Venice lagoon experiencing a drastic decline in the last decades. In order to define the molecular mechanisms behind sediment toxicity, we exposed clams to sediments sampled from different sites within one of the Venice lagoon navigable canals close to the industrial area. Moreover, we investigated the impacts of dredged sediments on clam’s microbial communities.ResultsConcentrations of the trace elements and organic chemicals showed increasing concentrations from the city of Venice to sites close to the industrial area of Porto Marghera, where PCDD/Fs and PCBs concentrations were up to 120 times higher than the southern lagoon. While bioaccumulation of organic contaminants of industrial origin reflected sediments’ chemical concentrations, metal bioaccumulation was not consistent with metal concentrations measured in sediments probably due to the activation of ABC transporters. At the transcriptional level, we found a persistent activation of the mTORC1 signalling pathway, which is central in the coordination of cellular responses to chemical stress. Microbiota characterization showed the over-representation of potential opportunistic pathogens following exposure to the most contaminated sediments, leading to host immune response activation. Despite the limited acquisition of new microbial species from sediments, the latter play an important role in shaping Manila clam microbial communities.ConclusionsSediment management in the Venice lagoon will increase in the next years to maintain and create new canals as well as to allow the operation of the new mobile gates at the three Venice lagoon inlets. Our data reveal important transcriptional and microbial changes of Manila clams after exposure to sediments, therefore reuse of dredged sediments represents a potential risk for the conservation of this species and possibly for other organisms inhabiting the Venice lagoon.

The Role of Sediment Records in Environmental Forensic Studies: Two Examples from Italy of Research Approaches Developed to Address Responsibilities and Management Options

The coupling of scientific evidence from sediment cores with historical information represents an effective way to reconstruct and quantify recent anthropogenic impacts in transitional and marine-coastal areas. These are both key points pertaining to studies that aim at establishing the responsibility for envi ronmental pollution. Good practices for the selection of sampling sites and specific survey techniques are fundamental to understand pollution histories and dynamics, together with reliable dating methods and analytical procedures. In addition, a certain degree of flexibility and willingness to explore different research pathways is necessary, particularly when unexpected questions arise from scientific data or from requests posed by authorities in charge of preliminary investigations or court debates. In this paper, two different study cases are reviewed, and the approaches developed to tackle with specific issues are presented. Its main purpose is both to explain study paths undertaken to answer challenging scientific-legal questions and to provide examples for developing countries that present similar risks of uncontrolled industrialization. Results were used in preliminary investigations or court debates for the attribution of responsibility for environmental pollution to past or present industrial managements. In addition, they were fundamental for other studies aiming at implementing models that simulate the fate and distribution of contaminants and human exposure. In the Augusta Harbor, an integrated approach merged archive information, bathymetry, and high-resolution seismic profiles with the results of an independent tracer (hexachlorobenzene, HCB). This approach helped attribute the presence of high surficial Hg concentrations to resuspension and redistribution of deep sediments caused by dredging and maritime traffic and not to active outfalls. In the Venice Lagoon, an extensive literature search supported analytical results for the correct identification of industrial processes responsible for the contamination by polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in the canals of the Porto Marghera Industrial Area. In addition, sedimentary profiles of PCDD/Fs in local salt marshes (“barene”) recorded well the events relative to the industrial development and management of the area reported by historical documents, confirming their potential for this kind of investigation.

Why is technocracy persistent in industrial risk? Empirical evidence from an in‐depth case study in Italy

AbstractRisk expertise is characterised by procedures that emphasise scientific and technical aspects of risk management and downplay citizens’ concerns and lay knowledge. In this paper, we aim at accounting for some of the reasons why technocracy is persistent in industrial risk expertise. Using the conceptual tools provided by the political sociology of expertise and based on empirical research conducted with mixed qualitative techniques, we study different types of expertise about industrial risk in the petrochemical area of Porto Marghera (Venice, Italy). The first one is performed by the Agenzia Regionale per la Protezione Ambientale del Veneto (ARPAV, Regional Agency of Veneto for Environmental Protection), which is responsible for chemical risk management, and the plants of the area. The second one is performed by the Assemblea permanente contro il pericolo chimico (APCPC, Permanent Assembly Against Industrial Risk), a citizens’ association of the neighbouring community of Marghera. In this case study, we show that technocratic procedures are persistent in industrial risk due to strategic relationships between the public administration in charge of risk regulation enforcement and private chemical companies, the absence of Italian laws on inclusive participatory arenas about industrial risk, and the characteristics of the citizens’ mobilisation, which focuses on plants’ delocalisation rather than challenging the ARPAV's and plants’ technocracy.

Situating class in workplace and community environmentalism: Working-class environmentalism and deindustrialisation in Porto Marghera, Venice

This article explores the challenges faced by working-class environmentalism through the case study of the industrial decline of Porto Marghera’s petrochemical complex, in Venice, Italy. It argues that there is a class dimension in environmentalist struggles in both workplaces and communities. Workplace-centred struggles are conflicts over the conditions under which workers produce commodities or reproduce labour-power, while community-centred struggles are conflicts over the conditions of workers’ own reproduction. The distinction between workplace-centred and community-centred struggles is based on three theoretical expansions: (1) a conception of working-class based on dispossession rather than exploitation; (2) a conception of work including both production and reproduction; (3) a conception of working-class interests encompassing both the workplace and the community. The article thus contributes to environmental labour studies with an original analysis of the interplay between workplace-centred and community-centred working-class environmentalist struggles. In Porto Marghera, in the 1990s and 2000s, the community-centred and workplace-centred working-class environmentalist camps diverged over chlorine-based production, with the former demanding a just transition away from chlorine and the latter a just transition within it. While the rival mobilisations limited damage to health and the environment on the one hand, and to chlorine workers’ livelihoods on the other hand, chlorine-based production was closed without full environmental remediation and without the relocation of all its workers to comparable jobs. The article concludes that the convergence between workplace and community organising is a critical step in the construction of alternatives to the jobs versus environment dilemma.

Letteratura per l’infanzia e l’adolescenza dal/del Nord-Est Italia. Una analisi degli eco-assi da Salgari a Scarpa (1901–2021)

Over the last hundred years and since the Second World War at the speed of the Great Acceleration, the Anthropocene has been intensively impacting the Northeast of Italy and, as a result, redrawn the Triangolo Industriale, shifting it towards the East, whereby its two prior western cities – Turin and Genoa – have been replaced with the production hubs scattered along the Via Emilia and Veneto. The coastal region has seen the foundation and robust growth of Porto Marghera with its freight, metallurgy, chemical, mechanical, shipbuilding, oil and electricity sectors; the Veneto plain has witnessed an expansion of SMEs; and Emilia has become home to multinational corporations. While not subject to industrialisation, the mountains of the Triveneto have not been exempt from a thorough modernisation on the scale unparalleled in the Italian Alps. Considering these changes, this paper surveys a range of literary works from Salgari to Scarpa (via Albertazzi, Zavattini, Buzzati, Guerra, D’Arzo, Pratt, Malerba, Altan, Nanetti, Benni, Rigoni Stern, Molesini, Costa, Corona, Carminati, Sgardoli, Tamaro, Tessaro and Ervas) in order to establish what role is given to environmental issues by the authors of children’s literature in the Northeast and whether (dis)continuities emerge in the body of their writings in this respect. The paper also investigates which authors present an active sensitivity useful for fostering an eco-consciousness and in what ways they do so. The methodology combines an array of critical tools developed in eco-pedagogical criticism, ecofeminism and the NatCul Matrix, geared to answering a series of questions: (1) Is basic environmental literacy offered? (2) Is a critical reflection on human primacy and environmental (in)sustainability implicit, explicit or absent? (3) How are humanity and nature related in children’s literature? (4) How is eco-justice approached? (5) What attitudinal role does the narrative assign to nature?

Mortality for Lung Cancer among PVC Baggers Employed in the Vinyl Chloride Industry.

Vinyl-chloride monomer (VCM) is classified as a known carcinogen of the liver; for lung cancer, some results suggest a potential association with polyvinyl chloride (PVC) dust. We evaluated the relationship between lung cancer mortality and exposure as PVC baggers in a cohort of workers involved in VCM production and polymerization in Porto Marghera (Venice, Italy) considering both employment status and smoking habits. The workers were studied between 1973 and 2017. A subset of them (848 over 1658) was interviewed in the 2000s to collect information about smoking habits and alcohol consumption. Missing values were imputed by the Multivariate Imputation by Chained Equations (MICE) algorithm. We calculated standardized mortality ratios (SMR) and 95% confidence intervals (95% CIs) using regional reference rates by task (never, ever, and exclusively baggers) and by smoking habits. Mortality rate ratios (MRR), adjusted for age, calendar time, time since first exposure, and smoking habits, were obtained via Poisson regression using Rubin’s rule to combine results from imputed datasets calculating the fraction of information due to non-response. Lung cancer mortality was lower than the regional reference in the whole cohort (lung cancer SMR = 0.92; 95% CI 0.75–1.11). PVC baggers showed a 50% increase in lung cancer mortality compared to regional rates (SMR = 1.48; 95% CI 0.82–2.68). In the cohort analyses, a doubled risk of lung cancer mortality among PVC baggers was confirmed after adjustment for smoking and time-dependent covariates (MRR = 1.99, 95% CI 1.04–3.81). Exposure to PVC dust resulting from activity as bagger in a polymerization PVC plant was associated with an increase in lung cancer mortality risk after adjustment for smoking habits.

Long-lasting effects of chronic exposure to chemical pollution on the hologenome of the Manila clam.

Chronic exposure to pollutants affects natural populations, creating specific molecular and biochemical signatures. In the present study, we tested the hypothesis that chronic exposure to pollutants might have substantial effects on the Manila clam hologenome long after removal from contaminated sites. To reach this goal, a highly integrative approach was implemented, combining transcriptome, genetic and microbiota analyses with the evaluation of biochemical and histological profiles of the edible Manila clam Ruditapes philippinarum, as it was transplanted for 6 months from the polluted area of Porto Marghera (PM) to the clean area of Chioggia (Venice lagoon, Italy). One month post‐transplantation, PM clams showed several modifications to its resident microbiota, including an overrepresentation of the opportunistic pathogen Arcobacter spp. This may be related to the upregulation of several immune genes in the PM clams, potentially representing a host response to the increased abundance of deleterious bacteria. Six months after transplantation, PM clams demonstrated a lower ability to respond to environmental/physiological stressors related to the summer season, and the hepatopancreas‐associated microbiota still showed different compositions among PM and CH clams. This study confirms that different stressors have predictable effects in clams at different biological levels and demonstrates that chronic exposure to pollutants leads to long‐lasting effects on the animal hologenome. In addition, no genetic differentiation between samples from the two areas was detected, confirming that PM and CH clams belong to a single population. Overall, the obtained responses were largely reversible and potentially related to phenotypic plasticity rather than genetic adaptation. The results here presented will be functional for the assessment of the environmental risk imposed by chemicals on an economically important bivalve species.

Metal Bioaccumulation and Oxidative Stress in Ulva laetevirens in the Venice Lagoon: Early Warning Biomarker for Metal Bioaccumulation

Transitional water systems (TWSs) may be threatened by various metals originating from increased agricultural, industrial activities, or urban effluents. Macroalgae are one of the biological quality elements used to monitor and assess the health status of TWS due to their structural and functional key role in marine ecosystems. Here, metal accumulation from the macroalgae Ulva laetevirens Areschoug (1854) and oxidative stress by lipid peroxidation (LPO) biomarker were investigated during four sampling seasons from three sampling sites (SMM: Santa Maria del Mare; PM: Porto Marghera; SG: San Giuliano) of Venice Lagoon, affected by different anthropogenic stressors. The metal pollution index (MPI) scores for U. laetevirens increased in the order SMM < PM < SG (sea inlet < industrial area < Osellino River estuary), with average values per site of 2.99, 4.37, and 6.33, respectively. The level of LPO was statistically correlated with the concentration of toxic metal(loid)s (As, Pb, Hg) measured in macroalgae, and seasonality affected both levels of LPO and metal bioaccumulation, with peak values during spring and summer. These findings highlighted the efficiency and usefulness of the oxidative stress test (LPO) on the common macroalga U. laetevirens as an early warning signal for health assessment in aquatic ecosystems.

Towards a bioenergy transition in Italy? Exploring regional stakeholder perspectives towards the Gela and Porto Marghera biorefineries

This paper investigates two transition initiatives at the local level – namely the reconversion of the Porto Marghera and Gela refineries into biorefineries for second-generation biofuels. The study aimed at assessing the extent to which the narrative pressures exerted by local actors influenced the perspectives of key stakeholders involved in these transition processes. To this end, a blended methodology was employed, combining discourse analysis with stakeholder analysis and semi-structured interviews. First, stakeholders were grouped into four categories according to the source (national/global) and channel (formal/informal) of pressure. National/informal actors emerged as the most influential group. The discourse analysis identified three dominant storylines representing complementary trajectories defined by national actors operating through informal channels. Finally, semi-structured interviews with key local actors involved in the Porto Marghera and Gela reconversions were used to assess the impact of these storylines in the reconversion processes. Comparison of the two cases revealed fundamental specificities related to their respective cultural, political and socio-economic contexts. While the Porto Marghera reconversion was presented as a consolidated success story (albeit with a number of drawbacks related to the fact that it was still mainly powered by first-generation feedstocks), the Gela case was viewed as a complex and challenging ongoing process with an uncertain outcome.

Green gentrification as strategic action: Exploring the emerging discursive and social support for the Green Tree Strategy in Porto Marghera, Italy

This paper contributes to the critical literature that links greening initiatives with the risk of gentrification. As urban areas become greener and provide high quality amenities, they attract wealthier residents, thus channelling the benefits of greening to a few. Most existing research has analysed the results of greening initiatives once they have been completed. This article explores green gentrification as a form of strategic action, by analysing the emerging Green Tree Strategy (GTS) for Porto Marghera, Italy. This area has undergone historical greening initiatives, beginning with the “garden city” of Enebezeer Howard (1902). The GTS is the newest green regeneration initiative in Porto Marghera. The data were collected via semi-structured interviews and through an online social network survey. The results show that the GTS has a clear ideological core – built around a new strategy of perception – but also that its appeal can be challenged in terms of industrial and employment displacement. The support for the GTS is fragmented and lacks consensus in Porto Marghera. However, if local actors are to successfully resist further attempts at green gentrification, they likely need to build an alternative vision, organized around a balanced development between green infrastructures and social inclusiveness.

Making sense of the industrial past: deindustrialisation and industrial heritage in Italy

This article analyses the relationship between deindustrialisation and industrial heritage by considering recent studies on the topic. Although Deindustrialisation Studies and (Industrial) Heritage Studies focus on distinct phases of industrial change — schematically a "before" and an "after" of the history of industry — these fields increasingly converge on the role of the memory of the industrial past in the present. The essay examines these convergences in the Italian context, looking at the history of industrial archaeology and the difficulty of recognising a specifically "Italian deindustrialisation". It argues that history, especially environmental and labour history, can play an important role in this dialogue. In the last part, the article focuses on the industrial area of Porto Marghera (near Venice) and analyses the major cultural events that were organised for its centenary. It argues that this is an example both of "deindustrialisation without industrial heritage" and of "industrial heritage without the memory of deindustrialisation". This makes it difficult to develop a shared elaboration of the area's industrial past and of its future.

The work-technology nexus and working-class environmentalism: Workerism versus capitalist noxiousness in Italy\u2019s Long 1968

This article traces the trajectory of theory and praxis around nocività or noxiousness – i.e., health damage and environmental degradation – drawn by the workerist group rooted in the petrochemical complex of Porto Marghera, Venice. While Porto Maghera was an important setting for the early activism of influential theorists such as the post-workerist Antonio Negri and the autonomist feminist Mariarosa Dalla Costa, the theories produced by the workers themselves have been largely forgotten. Yet, this experience was remarkable because it involved workers employed by polluting industries denouncing in words and actions the environmental degradation caused by their companies from as early as 1968, when the workerists had a determining influence in the local factories. The Porto Marghera struggles against noxiousness contradict the widespread belief that what is today known as working-class environmentalism did not have much significance in the labour unrest of Italy’s Long 1968. The Porto Marghera group’s original contribution was based on the thesis of the inherent noxiousness of capitalist work and an antagonistic-transformative approach to capitalist technology. This led to the proposal of a counterpower able to determine “what, how, and how much to produce” on the basis of common needs encompassing the environment, pointing to the utopian prospect of struggling for a different, anti-capitalist technology, compatible with the sustainable reproduction of life on the planet.

Clusters in formation in a deindustrialized area: urban regeneration and structural change in Porto Marghera (Venice)

PurposeThis paper aims to provide a comprehensive vision of the formation of intra-metropolitan clusters triggered by the deindustrialization of an urban area, namely, the district of Porto Marghera in the metropolitan area of Venice and propose possible regeneration scenarios based on intra-metropolitan clustering.Design/methodology/approachThis paper adopts a multi-disciplinary approach and relies on both descriptive and qualitative evidence to show the economic transition occurred in the area of Porto Marghera in recent years.FindingsEvidence shows the rise of two potential clusters in the KIBS and the creative industries in a well-delimited fringe area placed at the boundary between the urban centre and the core of the deindustrialized zone. Such clustering processes have been, however, characterized by two different and in some way alternative paths. The former stems from the combination of two autonomous entrepreneurial ideas that complemented one to each other. The latter relies on university-industry collaboration and on the presence of places of informal exchanges that proved to support personal networking, knowledge exchange and business opportunities.Research limitations/implicationsThis paper suggests that local development policies could leverage on the presence of social entrepreneurs to substitute the creation of amenities and the provision of public goods in fragile territories.Originality/valueThis paper shows that, in presence of specific spatial conditions, deindustrialization can stimulate the formation of new intra-metropolitan through both top-down and bottom-up agglomeration process.

Assessment of brownfield redevelopment opportunities using a multi-tiered approach: A case in Italy

The objectives and implementation of environmental remediation and regeneration of brownfield sites have evolved over the years. Today, the intertwining of environmental, economic, and social issues related to the reuse of these sites is more apparent than in previous years; thus, the interconnectedness of these issues is now more considered in the remediation and regeneration of brownfield sites. The implications of environmental remediation and regeneration activities have broadened, leading to different and often contrasting interests among the stakeholders involved in these activities. In this study, we analyzed the role of private and public stakeholders in the remediation and regeneration of a brownfield site in Porto Marghera, Italy (Venice). We also examined the influence of the brownfield's site-specific features on its own remediation and regeneration. By adopting a multi-tiered approach, including, first, a desktop analysis and, second, in-depth interviews and a multi-criteria decision analysis, we identified factors that, if present or improved, could enhance the attractiveness of the area to developers and foster the site's redevelopment.

Building public innovation for industrial risk prevention and crisis management: Genesis and development of a unique collaborative innovation

Public innovation is a peculiar form of innovation that provides new policies, new products, new services, and new infrastructures to increase public value. Many barriers can prevent this kind of innovation, so it cannot be taken for granted. Consequently, it is important to understand the conditions that can produce it. The present article is a case study on SIMAGE, a collaborative public innovation that has no equivalent in Europe and was developed in the Italian petrochemical site of Porto Marghera (in the municipality of Venice) for industrial risk prevention and crisis management. Based on sociological research conducted with qualitative techniques, I aim at accounting for the genesis and development of the process that led the public and the private sector to build jointly an effective public innovation through collaboration. The conclusion focuses on innovation processes, on the production of public goods by the public and the private sector, and on risk and crisis governance.

Estudiar, inventar y conocer el Porto Marghera de Venecia

En este artículo, se discute sobre como leer, analizar y conocer un espacio complejo como Porto Marghera, el distrito industrial de la ciudad italiana de Venecia. Los resultados de la investigación académica se presentan como Atlas: un conjunto de descripciones que se muestran en sus diferentes representaciones diagramáticas, para proporcionar instrumentos útiles a la hora de descifrar la forma compleja del lugar. El Atlas tiene en cuenta todos lo que se encuentran en la vasta área: edificios, infraestructuras, suelos y espacios libres; los denomina, los pone en un listado, los cataloga, los describe, los ordena, los selecciona según jerarquías manifestadas, pudiendo implementarlas sin limitaciones según las necesidades e hipótesis de lectura. El Atlas se configura como un conjunto de repertorios y colecciones que abren múltiples oportunidades para proyectos de regeneración territorial. El fundamento que ha orientado la recolección del material es el resarcimiento ambiental y funcional.

Significance of the goby Zosterisessor ophiocephalus as a sentinel species for Venice Lagoon contamination: Combining biomarker responses and bioaccumulation

The Venice Lagoon is an interesting example of an ecosystem suffering for a considerable anthropogenic impact, resulting in high concentrations of persistent organic pollutants (POPs) in lagoon sediments and seafood. In this context, biomonitoring is a crucially important task.The present study aimed at evaluating the validity of a multiple biomarker approach in a benthic fish species. A total of 567 Zosterisessor ophiocephalus (Gobiidae) fish were collected in spring and autumn from three areas of Venice Lagoon (Porto Marghera, Val di Brenta, and Cà Roman) showing high, intermediate and low amounts of POPs, respectively. Aryl hydrocarbon receptor (AHR) and cytochrome P450 1A (CYP1A) mRNA levels, CYP1A protein amount and ethoxyresorufin O-deethylase activity (EROD) were measured in pooled liver and gills (mRNA levels only). Such biological data were then compared with polychlorinated biphenyls (PCBs) residues, measured in grass goby muscle by gas chromatography.Aryl hydrocarbon receptor and CYP1A mRNAs, protein and EROD were upregulated in accordance with PCB amounts measured in Z. ophiocephalus muscles. In fact, the highest AHR and CYP1A induction was observed in fish sampled in close proximity of the industrial area of Porto Marghera.Overall, the present study confirm the grass goby as a reliable sentinel species for Venice Lagoon, and AHR/CYP1A/EROD as a sensitive set of biomarkers of exposure for AHR ligands.

Sediment texture and metal contamination in the Venice Lagoon (Italy): A snapshot before the installation of the MOSE system

Sediments of the Venice Lagoon down to 50 cm depth were investigated to assess sediment texture and metal contamination status, before the construction and activation of the MOSE system, which is intended to prevent the periodical flood events affecting the lagoon and the city of Venice. 380 cores were collected in shallow-water areas of the lagoon, and analysed along their vertical profile to determine grain-size distribution and concentrations of some major and trace elements (Al, As, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn), total carbon and organic carbon. Radionuclide analyses (137Cs, 210Pb) were performed on 15 cores in an attempt to establish sediment chronology and determine radionuclide inventories in erosional and depositional areas.On the whole-lagoon scale, strong depletion of particles <31 μm in diameter (from medium silt to clay fractions) was observed in sediments down to 10 cm depth in comparison to deeper layers. This depletion characterised both erosional and depositional areas, and may be caused by increased water dynamics and resuspension of sediment due to anthropogenic activities.The apparent sediment accumulation rate determined with 210Pbxs in depositional areas was estimated at 0.2–0.4 cm y−1. In the majority of cores, 210Pbxs inventories were lower than expected from atmospheric fallout, suggesting its export along with fine particles.The different sediment characteristics in terms of grain-size distribution and organic carbon content observed in the upper layer with respect to the deeper ones reflect the modification of the sedimentary balance in recent years. The loss of fine particles, even from sediments in depositional areas of the northern part of the lagoon, may herald changes in local sediment texture leading to a further depletion of morphodiversity, which in turn may lead to the reduction or loss of important lagoon habitats.On the whole-lagoon scale, the prevalently lithogenic elements (Al, As, Cr, Fe, Mn, Ni) decreased towards the top of the cores, reflecting the depletion of fine particles in the upper sediment layer due to winnowing in non-confined lagoon areas. In contrast, partly anthropogenic elements (Cu, Hg, Pb, Zn) increased up to the subsurface sediment layers (5–10 and/or 10–20 cm) as an effect of increasing pollutant inputs until a certain time in the past. Enrichment Factors (EF) were calculated from 9 cores, comparing concentrations in the “pre-industrial” (>100 years ago) and recent (surface layer, 0–5 cm) sediments. The mostly lithogenic elements were not enriched (EF ˜ 1), whereas the partly anthropogenic elements showed slight (Cu and Pb, EF ˜ 1.2) to significant (Hg and Zn, EF ˜ 2) enrichment. The shallow waters on the landward side (particularly close to freshwater inputs), the area nearby the industrial district of Porto Marghera and a small zone adjacent to the city of Chioggia were identified as the main pollutant accumulation sites. Mercury was the only element potentially harmful for aquatic life. Its concentration in the biologically active surface sediment layer (0–5 cm) exceeded the NOAA Effects Range-Median (ERM) value in 27% of samples, corresponding to 20% of the shallow-water surface area.The collected data set represents a valuable reference for monitoring the impact of the construction and operation of the MOSE system on the sediment features of the Venice Lagoon.

Microbiota and environmental stress: how pollution affects microbial communities in Manila clams

Given the crucial role of microbiota in host development, health, and environmental interactions, genomic analyses focusing on host-microbiota interactions should certainly be considered in the investigation of the adaptive mechanisms to environmental stress. Recently, several studies suggested that microbiota associated to digestive tract is a key, although still not fully understood, player that must be considered to assess the toxicity of environmental contaminants. Bacteria-dependent metabolism of xenobiotics may indeed modulate the host toxicity. Conversely, environmental variables (including pollution) may alter the microbial community and/or its metabolic activity leading to host physiological alterations that may contribute to their toxicity. Here, 16s rRNA gene amplicon sequencing has been applied to characterize the hepatopancreas microbiota composition of the Manila clam, Ruditapes philippinarum. The animals were collected in the Venice lagoon area, which is subject to different anthropogenic pressures, mainly represented by the industrial activities of Porto Marghera (PM). Seasonal and geographic differences in clam microbiotas were explored and linked to host response to chemical stress identified in a previous study at the transcriptome level, establishing potential interactions among hosts, microbes, and environmental parameters. The obtained results showed the recurrent presence of putatively detoxifying bacterial taxa in PM clams during winter and over-representation of several metabolic pathways involved in xenobiotic degradation, which suggested the potential for host-microbial synergistic detoxifying actions. Strong interaction between seasonal and chemically-induced responses was also observed, which partially obscured such potentially synergistic actions. Seasonal variables and exposure to toxicants were therefore shown to interact and substantially affect clam microbiota, which appeared to mirror host response to environmental variation. It is clear that understanding how animals respond to chemical stress cannot ignore a key component of such response, the microbiota.