Monitoring the impact of litter in large vertebrates in the Mediterranean Sea within the European Marine Strategy Framework Directive (MSFD): constraints, specificities and recommendations

Global Meta-Analysis and Review of Microplastic in Marine Copepods

Plastic pollution has spread through all parts of the marine environment, representing a significant threat to species and ecosystems. This study investigates the role of copepods as widespread microplastic reservoirs in the marine environment, by performing, a systematic review, meta-analysis, and semiquantitative analysis of scientific articles focusing on the interaction between copepods and microplastics under field conditions. Our findings indicate that despite uniformly low ingestion of microplastics across different marine layers and geographical areas, with a slight uptake in neustonic copepods, copepods might constitute one of the largest marine microplastic reservoirs. This phenomenon is attributed more to their vast abundance than to average microplastic ingestion values. In this article, a framework for data analysis and reporting is proposed to facilitate future large-scale evaluations and modelling of their extent and impact on plastic and carbon cycles. These insights place copepods at the forefront of the marine plastic cycle, possibly affecting plastic distribution, and bioavailability, thereby opening new pathways for understanding the complex dynamics of microplastics in marine ecosystems.

Marine turtles as bio-indicators of plastic pollution in the eastern Mediterranean

The loggerhead turtle (Caretta caretta) has been suggested as a bio-indicator species for plastic pollution. However, detailed investigations in the eastern Mediterranean are limited. Here, we present data from loggerhead turtles (2012-2022; n = 131) of which 42.7 % (n = 57) had ingested macroplastic (pieces ≥ 5 mm). Frequency of occurrence (%) was not found to have changed over time, with body size (CCL cm), between stranded or bycaught turtles, or with levels of digesta present. The characteristics of ingested plastic (n = 492) were largely sheetlike (62 %), clear (41 %) or white (25 %) and the most common polymers identified were Polypropylene (37 %) and Polyethylene (35 %). Strong selectivity was displayed towards certain types, colours and shapes. Data are also presented for posthatchling turtles (n = 4), an understudied life stage. Much larger sample sizes will be needed for this species to be an effective bio-indicator, with the consideration of monitoring green turtles (Chelonia mydas) for the eastern Mediterranean recommended allowing a more holistic picture to be gathered.

Toxic metals in Loggerhead sea turtles (Caretta caretta) stranded freshly dead along Sicilian coasts

BACKGROUND

The Loggerhead sea turtle (Caretta caretta) is a marine reptile belonging to a monophyletic group of chelonians. As these animals are long-lived, they have the ability to accumulate pollutants.

AIM

To collect epidemiological data on toxic metals in marine Loggerhead sea turtles.

MATERIALS AND METHODS

Forty Loggerhead sea turtles comprising 25 males and 15 females stranded freshly dead between 2013 and 2018 along the coasts of Sicily, Southern Italy, were examined for arsenic, cadmium, and lead accumulation in muscle and adipose tissues by means of a validated ICP-MS method. A modified K index as a growth condition factor, namely Fulton's K index, was used. Samples were tested in duplicate. A Wilcoxon rank sum test was carried out to evaluate metal contents differences between muscle and adipose tissues and between genders.

RESULTS

The Fulton's K index suggested a good body condition of the C. caretta recovered with mean values of 5.34 ± 3.40 (n = 40; ±SD). Detectable concentrations of lead were found in 70% of the samples analysed with mean values of 0.65 ± 1.67 mg/kg wet weight and 0.51 ± 1.29 mg/kg wet weight in muscle and adipose tissues, respectively. No significant differences in arsenic, cadmium, and lead were detected between genders. In addition, no significant correlation was found between modified K index and concentrations of arsenic, cadmium, and lead.

CLINICAL RELEVANCE

Findings on muscle and adipose tissues suggest chronic exposure of Caretta caretta to high concentrations of especially lead which might negatively affect health and welfare of these marine turtles although body condition was good.

Surface-associated bacterial assemblages on marine anthropogenic litter in the intertidal zone of the Arabian Sea, India

Anthropogenic marine litter (mainly plastic pollution) is a serious concern globally. The interactions between terrestrial and marine ecosystems lead to the accumulation of marine litter in the intertidal zone. The biofilm-forming bacteria tend to colonize on surfaces of marine litter which are composed of diverse bacteria and are less studied. The present study investigated the bacterial community composition using both culturable and non-culturable (Next-generation sequencing (NGS)) approaches associated with the marine litter (polyethylene (PE), styrofoam (SF) and fabric (FB)) at three distinct locations (Alang, Diu and Sikka) of the Arabian Sea, Gujarat, India. Predominant bacteria observed using culturable and NGS techniques belonged to Proteobacteria phyla. Alphaproteobacteria class dominated on polyethylene and styrofoam surfaces in the culturable fraction among the sites while the Bacillus dominated fabric surfaces. In the metagenomics fraction, Gammaproteobacteria dominated the surfaces except for PE and SF surfaces from Sikka and Diu, respectively. The PE surface at Sikka was dominated by Fusobacteriia while SF surface from Diu was dominated by Alphaproteobacteria. Both culture-dependent and NGS approaches identified hydrocarbon-degrading bacteria as well as pathogenic bacteria on the surfaces. The outcome of the present study illustrates diverse bacterial assemblages which occur on marine litter and increases our understanding of the plastisphere community.

The relationship between microplastics in eastern oysters (Crassostrea virginica) and surrounding environmental compartments in Long Island Sound

Microplastics (MP, <5 mm) are found in coastal waters across various environmental compartments (biota, water, marine snow, sediment). The eastern oyster (Crassostrea virginica) is a commercially important species that ingests MP; however, oysters are discriminant suspension feeders that do not consume all particles to which they are exposed. This study explored the relationship between MP in oysters on a recreational oyster bed and the surrounding environmental compartments in Long Island Sound (LIS; USA). The quantity and types of MP in oysters, water, marine snow, and sediment samples were determined. Precautions were taken to minimize and monitor MP contamination in the field and laboratory to improve the quality of data collected. Microplastics were isolated from samples via chemical digestion, and any suspected particles were identified using micro-Fourier transform infrared spectroscopy. A total of 86 MP were identified out of 885 suspected particles across environmental media. The highest MP count in an individual oyster was nine, indicating low concentrations of MP in oysters and the surrounding environment. Few polymers, except polyethylene terephthalate, were shared between oysters and the surrounding environmental compartments. Sediments contained the highest number of MP across all environmental compartments (42 total). These data aid in determining the types of MP (polymer composition, shape, size) to which oysters are exposed and identified those ingested. The low numbers of MP recorded, coupled with the lack of alignment of polymers between oysters and their surrounding environment, demonstrates further that oysters are a poor bioindicator species for MP pollution.

Microplastics in large marine animals stranded in the Republic of Korea

Microplastics (MPs) are found in every ocean and are frequently ingested by marine animals. This study analyzed MPs in the stomachs and intestines of 12 large marine animals comprising one fin whale (Balaenoptera physalus), seven finless porpoises (Neophocaena asiaeorientalis), two loggerhead turtles (Caretta caretta), one Indo-Pacific bottlenose dolphin (Tursiops aduncus), and one common dolphin (Delphinus delphis) that were stranded off the Republic of Korea between 2019 and 2021. MPs were detected with a mean abundance of 3.42 ± 3.2 items/g and were predominantly of transparent-white, fragment-shaped polypropylene smaller than 200 μm. The abundance of MPs found did not correlate with the biological information (maturity, body length) of the finless porpoises and there were no significant differences in the abundance of MPs between the stomachs and intestines. These results cannot accurately assess the impact of MPs on large marine animals, so further studies are necessary to understand how MPs can potentially affect them.

Mistaking plastic for zooplankton: Risk assessment of plastic ingestion in the Mediterranean sea

Floating plastic debris is a pervasive pollutant in seas and oceans, affecting a wide range of animals. In particular, microplastics (<5 mm in size) increase the possibility that marine species consume plastic and enter the food chain. The present study investigates this potential mistake between plastic debris and zooplankton by calculating the plastic debris to zooplankton ratio over the whole Mediterranean Sea. To this aim, in situ data from the Tara Mediterranean Expedition are combined with environmental and Lagrangian diagnostics in a machine learning approach to produce spatially-explicit maps of plastic debris and zooplankton abundance. We then analyse the plastic to zooplankton ratio in regions with high abundances of pelagic fish. Two of the major hotspots of pelagic fish, located in the Gulf of Gabès and Cilician basin, were associated with high ratio values. Finally, we compare the plastic to zooplankton ratio values in the Pelagos Sanctuary, an important hotspot for marine mammals, with other Geographical Sub-Areas, and find that they were among the larger of the Western Mediterranean Sea. Our results indicate a high potential risk of contamination of marine fauna by plastic and advocate for novel integrated modelling approaches which account for potential trophic transfer within the food chain.

Marine citizenship: The right to participate in the transformation of the human-ocean relationship for sustainability

Marine citizenship is a relatively new field of enquiry and research to date has focused on individual pro-environmental behaviour change as an expression of responsibility towards the ocean. The field is underpinned by knowledge-deficit and technocratic approaches to behaviour change such as awareness raising, ocean literacy, and environmental attitudes research. In this paper we develop an interdisciplinary and inclusive conceptualisation of marine citizenship. We use mixed methods to study the views and experiences of active marine citizens in the United Kingdom to broaden understandings of marine citizens' characterisation of marine citizenship, and their perceptions of its importance in policy- and decision-making. Our study shows that marine citizenship entails more than individual pro-environmental behaviours, and includes public-facing and socially collective political actions. We contextualise the role of knowledge, finding more complexity than normative knowledge-deficit approaches permit. We illustrate the importance of a rights-based framing of marine citizenship which incorporates political and civic rights to participate in the transformation of the human-ocean relationship for sustainability. Recognising this more inclusive approach to marine citizenship, we propose an expanded definition to support further exploration of the multiple dimensions and complexities of marine citizenship and to enhance its benefits for marine policy and management.

Microplastics in seawater and marine organisms: Site-specific variations over two-year study in Giglio Island (North Tyrrhenian Sea)

Geographical and temporal differences of microplastic occurrence were documented in water and fish collected in 2017 and 2019 from the Giglio Island (North Tyrrhenian Sea) close to the area where the Costa Concordia sank in January 2012. Results on water samples showed a site-dependent difference, suggesting the role of surface current dynamics in the microplastic local distribution, while tested Neuston nets (200 μm and 330 μm mesh size) did not influence microplastic retention efficiency. Fish exhibited in 2019 a higher frequency of specimens positive to microplastic ingestion with respect to 2017, with an occurrence higher than those typically observed in other Mediterranean areas. Both in water and fish, fragments were the dominating shape, polypropylene and polyethylene were the prevalent polymers, without particular difference between sites and years. This study highlights the importance of applying microplastic investigation in biotic and abiotic matrices for an effective monitoring of this pollution in the marine environment.

Plastics in the environment as potential threat to life: an overview

Plastics have become inevitable for human beings in their daily life. Million tons of plastic waste is entering in oceans, soil, freshwater, and sediments. Invasion of plastics in different ecosystems is causing severe problems to inhabitants. Wild animals such as seabirds, fishes, crustaceans, and other invertebrates are mostly effected by plastic entanglements and organic pollutants absorbed and carried by plastics/microplastics. Plastics can also be potentially harmful to human beings and other mammals. Keeping in view the possible harms of plastics, some mitigation strategies must be adopted which may include the use of bioplastics and some natural polymers such as squid-ring teeth protein. This review focuses on the possible sources of intrusion and fate of plastics in different ecosystems, their potential deleterious effects on wildlife, and the measures that can be taken to minimize and avoid the plastic use.

Marine plastics in Mediterranean islands: Evaluating the distribution and composition of plastic pollution in the surface waters along four islands of the Western Sea Basin

To study the spatial distribution of sea surface plastics in marine protected and non-protected areas, 65 sea surface trawls were carried out using a Hydro-bios manta net coupled with a 335-μm mesh. A total of 19 sampling sites along the coastal waters of Mallorca, the "Parque Nacional Marítimo-Terrestre del Archipiélago de Cabrera" and Menorca in the Balearic Islands as well as along coastal waters of The Natural Park of Columbretes Islands (NW Mediterranean Sea) were sampled. A total of 10,637 plastic items were identified and a subset of these items was categorized by shape, color, size and polymer composition. Plastic particles were found at each sampling site and in all samples. No microscale nor mesoscale variability in floating marine plastics abundance (particles/m²) was encountered throughout the study area where similar values were found in protected areas with no local land-based contamination sources, such as Columbretes [0.04 (±0.03) particles/m²], and in high anthropized areas, such as the island of Mallorca [0.04 (±0.07) particles/m²]. However, differences were found in characteristics of plastic items (shape, polymer, and size range), with the protected area of Columbretes characterized by the presence of the highest density of very small plastic items composed mainly of fragments (93%). Quantified plastics from the marine environment were composed mainly of polyethylene (PE, 63.3%), polypropylene (PP; 24.9%), polycarbonate (PC; 4.6%) and polystyrene (PS, 3.3%). The polymer composition showed a homogenous composition between islands and differences were detected only amongst Columbretes and the other islands. Results from this study provide further evidence of the ubiquity of plastics in the marine environment and highlight that remote and protected areas, such as Columbretes, are not exempt from plastic pollution, but receptor areas for small and aged floating plastics composed mainly by fragments, which might have potentially harmful effects on protected ecosystems.

Marine Litter Detection by Sentinel-2: A Case Study in North Adriatic (Summer 2020)

Aggregates of floating materials detected in North Adriatic in six Sentinel-2 scenes of August 2020 have been investigated. Most of the floating materials were identified by the chlorophyll red edge and consisted of vegetal materials, probably conveyed by rivers and exchanged with the lagoons. Traces of marine litter were looked for in the spectral anomalies of the Red Edge bands, assuming changes of the red edge in pixels where marine litter was mixed with vegetal materials. About half of the detected patches were unclassified due to the weakness of the useful signal (pixel filling percentage < 25%). The classification produced 59% of vegetal materials, 16% of marine litter mixed with vegetal materials and 22% of intermediate cases. A small percentage (2%) was attributed to submerged vegetal materials, found in isolated patches. The previous percentages were obtained with a separation criterion based on arbitrary thresholds. The patches were more concentrated at the mouths of the northern rivers, less off the Venice lagoon, and very few outside the Po River, with the minimal river outflow during the period. Sentinel-2 is a valid tool for the discrimination of marine litter in aggregates of floating matter. The proposed method requires validation, and the North Adriatic is an excellent site for field work, as in summer many patches of floating matter form in proximity to the coast.

An In Situ Experiment to Evaluate the Aging and Degradation Phenomena Induced by Marine Environment Conditions on Commercial Plastic Granules

In this paper, we present two novel experimental setups specifically designed to perform in situ long-term monitoring of the aging behaviour of commercial plastic granules (HDPE, PP, PLA and PBAT). The results of the first six months of a three year monitoring campaign are presented. The two experimental setups consist of: (i) special cages positioned close to the sea floor at a depth of about 10 m, and (ii) a box containing sand exposed to atmospheric agents to simulate the surface of a beach. Starting from March 2020, plastic granules were put into the cages and plunged in seawater and in a sandboxe. Chemical spectroscopic and thermal analyses (GPC, SEM, FTIR-ATR, DSC, TGA) were performed on the granules before and after exposure to natural elements for six months, in order to identify the physical-chemical modifications occurring in marine environmental conditions (both in seawater and in sandy coastal conditions). Changes in colour, surface morphology, chemical composition, thermal properties, molecular weight and polydispersity, showed the different influences of the environmental conditions. Photooxidative reaction pathways were prevalent in the sandbox. Abrasive phenomena acted specially in the sea environment. PLA and PBAT did not show significant degradation after six months, making the possible reduction of marine pollution due to this process negligible.

Neustonic microplastics and zooplankton in coastal waters of Cabrera Marine Protected Area (Western Mediterranean Sea)

The high abundance of microplastics in marine environments is becoming a growing threat for Marine Protected Areas (MPAs). Recent studies have identified microplastics (MP) as having multiple effects on biota, and it is of special interest to highlight their effects on zooplanktonic organisms. These organisms play a key role on local food web structures and there is a need to better understand the accumulation of MPs and associated contaminants within the food web. The present study addresses MP distribution and composition within Cabrera MPA as well as its effects on local zooplanktonic community composition. Neustonic microplastic and zooplankton abundance and composition were determined in the shallow coastal waters of Cabrera MPA during the summer season of 2019. Samples were taken using a sea surface manta-net, with a mesh size of 335 μm. MPs were found in all manta trawl samples for a total of 7047 MP with an overall mean abundance (± SD) of 3.52 (± 8.81) items/m³, a value higher than those reported for the majority of Western Mediterranean Sea basins. Qualitative and semi-quantitative analyses of the local zooplankton community suggest that its composition could be sensitive to MP abundances. Although no correlation was found between overall mean abundance of MP and zooplankton, a positive correlation was found between MP abundance and the abundance of the planktonic stage of the foraminifer Rosalina globularis (Tretomphalus). This species seems to be able to use MP for its dispersion. On the other hand, a negative correlation between MP abundance and Copepoda abundance was detected. This work confirms that the coastal zooplankton community composition within the MPA of Cabrera are not exempt from MP pollution and suggests important and complex interactions between MP and zooplankton organisms in coastal waters.

Microplastics pollution along the central Atlantic coastline of Morocco

This baseline study describes the microplastic (MPs) problem on seven beaches located on Agadir, central Atlantic coast of Morocco. Microplastics abundances (densities) ranged from 7680 MPs/kg to 34,200 MPs/kg above other world beaches. The following shapes were found: fibers, fragments, films, and pellets. Fibers were the dominant typology with a 73%. Polyethylene (PE) was the predominant polymer in all beaches with an average percentage of 59%, followed by Polypropylene (PP - 18%), Polystyrene (PS - 9%), Polyvinyl chloride (PVC - 8%), and Ethylene-vinyl acetate (EVA - 6%). Microplastics abundances presented in this work suggest continuous inputs of plastics of all sizes and types. Also, all observed shapes highlight a combination of sources (primary and secondary). Central Atlantic Moroccan beaches are currently affected by extreme values of MPs that demand urgent interventions to restore environmental quality.

Personal protective equipment (PPE) pollution associated with the COVID-19 pandemic along the coastline of Agadir, Morocco

The increasing use of personal protective equipment (PPE) as a sanitary measure against the new coronavirus (SARS-CoV-2) has become a significant source of many environmental risks. The majority of the governments enforce the use of PPE in public areas, such as beaches. Thus, the use and disposal of PPE have compromised most solid waste management strategies, ultimately leading to the occurrence of PPE polluting the marine environment. The present study aimed to monitor the PPE pollution associated with COVID-19 along the coastline of Agadir, Morocco. In parallel, the influence of the activities carried out in each sampled beach before and after the lockdown break was reported. Overall, a total number of 689 PPE items were identified, with a mean density of 1.13 × 10^-5 PPE m^-2 (0-1.21 × 10^-4 PPE m^-2). The majority of the PPE items found were face masks (96.81%), out of which 98.4% were surgical masks and 1.6% were reusable cloth masks. The most polluted sites were the beaches with recreational activities, followed by surfing, and fishing as the main activity. Importantly, PPE density increased significantly after lockdown measures. Additionally, the discarded PPE sampled in the supralittoral zone was higher than PPE recorded in the intertidal zone. This confirms that PPE items are driven by the beachgoers during their visit. PPE items are a source of microplastic and chemical pollutants, a substrate to invasive species colonization, and a potential threat of entanglement, ingestion, and/or infection among apex predators. In the specific case of Agadir beaches, significant efforts are required to work on the lack of environmental awareness and education. It is recommended to improve beach cleaning strategies and to penalize incorrect PPE disposal. Additional alternatives may be adopted, as the involvement of biodegradable materials in PPE manufacturing, recycling through pyrolysis, and encouraging reusable and washable masks.

Antimicrobial Resistance in Loggerhead Sea Turtles (Caretta caretta): A Comparison between Clinical and Commensal Bacterial Isolates

Simple Summary

Gram negative organisms are frequently isolated from Caretta caretta and may contribute to the dissemination of antimicrobial resistance. In this study, commensal bacteria isolated from oral and cloacal samples of 98 healthy C. caretta were compared to clinical isolates isolated from the wounds of 102 injured animals, in order to investigate the presence of antimicrobial resistance bacteria in free-living loggerheads from the Adriatic Sea. A total of 410 bacteria were cultured and differences were noted in the isolated genera, as some of them were isolated only in healthy animals, while others were isolated only from injured animals. When tested for susceptibility to antimicrobials, clinical isolates showed highly significant differences in the antimicrobial resistance rates vs. commensal isolates for all the drugs tested, except for doxycycline. The detection of high antimicrobial resistance rates in loggerhead sea turtles is of clinical and microbiological significance since it impacts both the choice of a proper antibiotic therapy and the implementation of conservation programs.

Abstract

Gram negative organisms are frequently isolated from Caretta caretta turtles, which can act as reservoir species for resistant microorganisms in the aquatic environment. C. caretta, which have no history of treatment with antimicrobials, are useful sentinel species for resistant microbes. In this culture-based study, commensal bacteria isolated from oral and cloacal samples of 98 healthy C. caretta were compared to clinical isolates from the wounds of 102 injured animals, in order to investigate the presence of AMR bacteria in free-living loggerheads from the Adriatic Sea. A total of 410 isolates were cultured. Escherichia coli and genera such as Serratia, Moraxella, Kluyvera, Salmonella were isolated only in healthy animals, while Acinetobacter, Enterobacter, Klebsiella and Morganella were isolated only from the wounds of the injured animals. When tested for susceptibility to ampicillin, amoxicillin + clavulanic acid, ceftazidime, cefuroxime, gentamicin, doxycycline, ciprofloxacin and enrofloxacin, the clinical isolates showed highly significant differences in AMR rates vs. commensal isolates for all the drugs tested, except for doxycycline. The detection of high AMR rates in loggerheads is of clinical and microbiological significance since it impacts both the choice of a proper antibiotic therapy and the implementation of conservation programs.

Antimicrobial-resistance profiles of gram-negative bacteria isolated from green turtles (Chelonia mydas) in Taiwan

The green turtle (Chelonia mydas) is listed as a globally endangered species and is vulnerable to anthropogenic threats, including environmental pollution. This study investigated the antimicrobial resistance of Gram-negative bacteria isolated from wild green turtles admitted to a sea turtle rehabilitation center in Taiwan. For this investigation, cloacal and nasal swab samples were collected from 28 green turtles between 2018 and 2020, from which a total of 47 Gram-negative bacterial isolates were identified. Among these, Vibrio spp. were the most dominant isolate (31.91%), and 89.36% of the 47 isolates showed resistance to at least one of 18 antimicrobial agents tested. Isolates resistant to one (6.38%), two (8.51%), and multiple (74.47%) antimicrobials were observed. The antimicrobial agents to which isolates showed the greatest resistance were penicillin (74.47%), followed by spiramycin, amoxicillin, and cephalexin. The antimicrobial-resistance profiles identified in this study provide useful information for the clinical treatment of sea turtles in rehabilitation facilities. The results of our study also imply that wild green turtles may be exposed to polluting effluents containing antimicrobials when the turtles traverse migratory corridors or forage in feeding habitats. To benefit sea turtle conservation, future research should focus on (1) how to prevent pollution from antimicrobials in major green turtle activity areas and (2) identifying sources of antimicrobial-resistant bacterial strains in coastal waters of Taiwan.

Detection of multi-drug resistance and AmpC β-lactamase/extended-spectrum β-lactamase genes in bacterial isolates of loggerhead sea turtles (Caretta caretta) from the Mediterranean Sea

Sea turtles are useful sentinels to monitor the dissemination of antimicrobial resistance (AMR) in the marine coastal ecosystems. Forty Gram negative bacteria were isolated from wounds of 52 injured Caretta caretta, living in the Mediterranean Sea. Bacteria were identified using 16S rRNA gene sequencing and tested for susceptibility to 15 antibiotics. In addition, NGS amplicon sequencing was performed to detect the presence of AmpC β-lactamase genes (bla_AmpC) and extended-spectrum β-lactamase (ESBL) genes (bla_CTX-M,bla_SHV,bla_TEM). Seventy-five percent of the isolates (30/40 isolates) exhibited multidrug resistance (MDR) phenotypes and 32.5% (13/40 isolates) were confirmed to be positive for at least one gene. The variants of ESBLs genes were bla_CTX-M-3,bla_TEM-236 and bla_SHV-12. Variants of the bla_AmpCβ-lactamase gene i.e., bla_ACT-24, bla_ACT-2, bla_ACT-17, bla_DHA-4 and bla_CMY-37, were also detected. In addition, 4 isolates were found simultaneously harboring CTX and AmpC genes while 2 strains harbored 3 genes (bla_{ACT-2+TEM-236+SHV-12}, and bla_{CTX-M-3+ACT-24+TEM-236}).

Surface-Enhanced Raman Spectroscopy Facilitates the Detection of Microplastics <1 μm in the Environment

Micro- and nanoplastics are considered one of the top pollutants that threaten the environment, aquatic life, and mammalian (including human) health. Unfortunately, the development of uncomplicated but reliable analytical methods that are sensitive to individual microplastic particles, with sizes smaller than 1 μm, remains incomplete. Here, we demonstrate the detection and identification of (single) micro- and nanoplastics by using surface-enhanced Raman spectroscopy (SERS) with Klarite substrates. Klarite is an exceptional SERS substrate; it is shaped as a dense grid of inverted pyramidal cavities made of gold. Numerical simulations demonstrate that these cavities (or pits) strongly focus incident light into intense hotspots. We show that Klarite has the potential to facilitate the detection and identification of synthesized and atmospheric/aquatic microplastic (single) particles, with sizes down to 360 nm. We find enhancement factors of up to 2 orders of magnitude for polystyrene analytes. In addition, we detect and identify microplastics with sizes down to 450 nm on Klarite, with samples extracted from ambient, airborne particles. Moreover, we demonstrate Raman mapping as a fast detection technique for submicron microplastic particles. The results show that SERS with Klarite is a facile technique that has the potential to detect and systematically measure nanoplastics in the environment. This research is an important step toward detecting nanoscale plastic particles that may cause toxic effects to mammalian and aquatic life when present in high concentrations.

Spatial and Temporal Distribution of Chemically Characterized Microplastics within the Protected Area of Pelagos Sanctuary (NW Mediterranean Sea): Focus on Natural and Urban Beaches

Data on the abundance and distribution of Anthropogenic Marine Debris (AMD) on the coastal areas of the northern Tyrrhenian coast are still scarce. The objective of this study is to characterize, in terms of size, color, morphology and polymeric nature, the Large Microplastics (LMPs), i.e., plastic objects within 1 and 5 mm, sampled on three beaches located within the coastal macro-area of the Pelagos Sanctuary, an international protected zone in the north-western Mediterranean. The beaches have similar morphological characteristics but different degrees of urbanization. LMPs were sampled seasonally for one year. The polymeric nature of a representative subsample of the collected LMPs was investigated using a portable Raman instrument, to assess the feasibility of in situ characterization. In this study, 26,486 items were sorted by typology (Expanded Polystyrene-EPS, fragments, and resin pellets), size, and for fragments and resin pellets, also by color and chemical nature. Statistical data on the quantity, density, type, spatial distribution, and seasonality of the sampled LMPs are presented. Differences in LMP abundance and composition were detected among sites. A seasonality trend emerges from our statistical analysis, depending on both LMP typology and urbanization degrees of the beaches. Our data do not show the existence of a relationship between the size of the investigated MPs and their color, while they suggest that the type of polymer influences the degree of fragmentation. This underlines the need to further investigate the mechanisms leading to the production and dispersion of MPs in coastal areas, taking into account both the urbanization of the beach, and therefore the possible sources of input, and the different types of MPs. Finally, a Raman portable instrument proved to be a valuable aid in performing in situ polymeric characterization of LMPs.

Numerical modeling of the beach process of marine plastics: 2. A diagnostic approach with onshore-offshore advection-diffusion equations for buoyant plastics

A model is proposed for the beach process of buoyant marine plastics, specifically its beaching and backwashing, by introducing beaching and backwashing diffusion coefficients and the onshore-offshore advection-diffusion equations of plastics for the upper layers in the beach and adjacent coastal sea. The backwashing diffusion coefficient was estimated from the average residence time of the beached plastics and the beach width, and then the beaching diffusion coefficient was estimated from the flux-balance assumption between the beaching and backwashing fluxes. Finite difference calculations in the staggered-grid system demonstrated that the amount of beached plastics responds as predicted by the linear system analysis when the beach had an exponential decay type of unit impulse response regardless of the ratio between the residence time and the period of beaching flux fluctuation from the nearshore. The condition in which the flux balance assumption holds was also discussed.

Effects of the UV filter, oxybenzone, adsorbed to microplastics in the clam Scrobicularia plana

Microplastics (MPs) lipophilic nature and widespread distribution raises concerns due to their increasing presence in the marine environment and their ability to adsorb organic contaminants, as being potential vehicles for transport and potential source of accumulation of organic contaminants by marine organisms. The organic UV-filter, oxybenzone (BP-3) is a constituent of sunscreens and personal care products, entering the marine environment either by direct contact with swimmers or by wastewater effluents. In this study the ecotoxicological effects of exposure to low-density polyethylene (LDPE) microplastics with and without adsorbed BP-3 were investigated in the peppery furrow shell clam, Scrobicularia plana. LDPE microplastics with a size range of 11-13 μm were previously contaminated with an environmentally relevant concentration of BP-3 (82 ng g^-1). S. plana individuals were exposed to a concentration of 1 mg L^-1 of microplastics with and without BP-3 adsorbed in a water-sediment exposure system for 14 days. Clams were sampled at the beginning of the experiment and after 3, 7, and 14 days of exposure. Multiple biomarkers were analysed to investigate the effect of exposure in different clam tissues, gills, digestive gland, and haemolymph. Antioxidant (superoxide dismutase, catalase, glutathione peroxidase) and biotransformation (glutathione-S-transferases) enzyme activities, oxidative damage (lipid peroxidation), genotoxicity (single and double strand DNA breaks), and neurotoxicity (acetylcholinesterase activity) were assessed along with two biomarker indexes to assess the overall health status. Results indicate that after 7 days of exposure MPs with adsorbed BP-3 induced oxidative stress and damage, when compared to exposure to virgin MPs and control treatments. Neurotoxic effects were also noted in MPs with adsorbed BP-3 after 14 days exposure, while some evidence points to increased genotoxicity with exposure time. Overall results indicate that gills were more affected by exposure to microplastics than digestive gland and that biomarkers alterations are apparently more related to the toxicity of BP-3 adsorbed than virgin MPs alone.

Lessons learned from an intercalibration exercise on the quantification and characterisation of microplastic particles in sediment and water samples

An intercalibration exercise on the characterisation of microplastics in marine sediment and water samples was carried out among five laboratories involved in the implementation of the Marine Strategy Framework Directive (MSFD) in their country. The samples were prepared by mixing cleaned natural sediment and sea water with microplastics sets made of particles of various polymers, shapes and colours. Overall, the errors on total counts were under 25% in absolute value. The risk of non-detection and loss of particles is greater than the risk of contamination during sample analysis. Significant differences are observed among particle types. It appears difficult to obtain reliable and comparable data on the colour of microplastics. A comparison of the errors with regards to the protocols used led to recommend NaCl [1.2 g/cm³] density separation for sediment and one filtering step (200 μm). The operators' experience appears as a key factor for the quality of the results.

Distribution and characterization of microplastic particles and textile microfibers in Adriatic food webs: General insights for biomonitoring strategies

This study provided a comprehensive characterization on ingestion of different typologies of microplastics in several fish and invertebrate species from the Adriatic Sea, considered as a preferential area of plastic accumulation in the Mediterranean. Almost 500 organisms were sampled in the three sectors of Northern, Central and Southern Adriatic, testing the hypothesis that area of collection, habitat and feeding strategy might influence the occurrence of plastic particles in biota. In this study, the overall characterization considered separately plastic microparticles (MPs) from textile microfibers (MFs) which also included natural and semi-synthetic ones. Ingestion of MPs was a widespread phenomenon, but their number (typically 1 or 2) did not reveal any significant relationship with biometric values, geographical areas or ecological features of the species. Conversely, the frequency of ingestion, ranging from 13 to 35% of organisms containing MPs, appeared a more reliable index to highlight such differences, revealing higher values in species from Central and Southern basins compared to the Northern one, as well as in benthopelagic compared to benthic or pelagic organisms. Geographical differences also occurred in terms of size and typology of ingested particles, suggesting the importance of local river runoffs and surface currents dynamics. Textile microfibers (MFs) were also abundant in Adriatic food webs occurring in all the analyzed species with average numbers (3-10) and frequencies (40-70%) higher than those reported for MPs; further, an elevated percentage of MFs (>80%) was of natural or semi-synthetic origin. Overall, this study provided general insights toward the harmonization of a common biomonitoring strategy, as in the context of MSFD, including the suggestion of a frequency-based index and of a multi-species approach to increase the ecological relevance of assessment, as well as the comparability between different areas and trophic webs.

Microplastics in Sea Turtles, Marine Mammals and Humans: A One Environmental Health Perspective

Microplastics are ubiquitous pollutants in the marine environment and a health concern. They are generated directly for commercial purposes or indirectly from the breakdown of larger plastics. Examining a toxicological profile for microplastics is a challenge due to their large variety of physico-chemical properties and toxicological behavior. In addition to their concentration, other parameters such as polymer type, size, shape and color are important to consider in their potential toxicity. Microplastics can adsorb pollutants such as polycyclic aromatic hydrocarbons (PAHs) or metals on their surface and are likely to contain plastic additives that add to their toxicity. The observations of microplastics in seafood increased concern for potential human exposure. Since literature considering microplastics in humans is scarce, using a One Environmental Health approach can help better inform about potential human exposures. Marine mammals and sea turtles are long-lived sentinel species regularly used for biomonitoring the health status of the ocean and share trophic chain and habitat with humans. This review considers the available research regarding microplastic and plastic fiber exposures in humans, marine mammals and turtles. Overall, across the literature, the concentration of microplastics, size, color, shape and polymer types found in GI tract and feces from sea turtles, marine mammals and humans are similar, showing that they might be exposed to the same microplastics profile. Additionally, even if ingestion is a major route of exposure due to contaminated food and water, dermal and inhalation studies in humans have provided data showing that these exposures are also health concerns and more effort on these routes of exposures is needed. In vitro studies looked at a variety of endpoints showing that microplastics can induce immune response, oxidative stress, cytotoxicity, alter membrane integrity and cause differential expression of genes. However, these studies only considered three polymer types and short-term exposures, whereas, due to physiological relevance, prolonged exposures might be more informative.

Loggerhead sea turtles as sentinels in the western Mediterranean: antibiotic resistance and environment-related modifications of Gram-negative bacteria

Sea turtles possess relevant characteristics to serve as sentinel species for monitoring the health of marine ecosystems, which is currently threatened. This study examined 35 loggerhead turtles from the western Mediterranean, focusing on the oral and cloacal prevalence of aerobic Gram-negative bacteria, their antibiotic resistance and the influence of several variables linked both to the animal and the environment (i.e. estimated life stage; area, season and cause of recovery; plastic ingestion). Conventional bacteriology methods led to the isolation of bacterial families commonly regarded as opportunistic pathogens (i.e. Aeromonadaceae; Enterobacteriaceae; Pseudomonadaceae; Shewanellaceae; Vibrionaceae), but pointing out sea turtles as carriers of potential zoonotic agents. The high rates of antibiotic resistance, here detected, raise important concerns on the dissemination of this phenomenon in marine environments. Moreover, several of the examined variables showed a significant influence on the prevalence of bacterial families, strengthening the role of sea turtles as mirrors of their ecosystems.

Seafloor litter from the continental shelf and canyons in French Mediterranean Water: Distribution, typologies and trends

Seafloor litter has been studied both on the continental shelves (by trawling during 24 years) and in canyons (by ROV) of the French Mediterranean sea Water (FMW). On the continental shelf, mean densities range from 49.63 to 289.01 items/km². The most abundant categories were plastic, glass/ceramics, metals and textiles. Trend analysis shows a significant increase in plastic quantities during the study period. Plastics accumulate at all depths, with heavier items being found in deeper areas, while the continental slope-break appears as a clean area. The spatial distribution of litter revealed the influence of geomorphologic factors, anthropic activities, shipping route, river inputs. All the canyons are affected by debris but coastal canyons (Ligurian Sea and Corsica) were more impacted than offshore canyons in the Gulf of Lion. The FMW appears to be highly polluted with regard to values found in other areas, but lower than those observed in the Eastern Mediterranean.

Diet-related selectivity of macroplastic ingestion in green turtles (Chelonia mydas) in the eastern Mediterranean

Understanding the drivers of key interactions between marine vertebrates and plastic pollution is now considered a research priority. Sea turtles are primarily visual predators, with the ability to discriminate according to colour and shape; therefore these factors play a role in feeding choices. Classification methodologies of ingested plastic currently do not record these variables, however here, refined protocols allow us to test the hypothesis that plastic is selectively ingested when it resembles the food items of green turtles (Chelonia mydas). Turtles in the eastern Mediterranean displayed strong diet-related selectivity towards certain types (sheet and threadlike), colours (black, clear and green) and shapes (linear items strongly preferred) of plastic when compared to the environmental baseline of plastic beach debris. There was a significant negative relationship between size of turtle (curved carapace length) and number/mass of plastic pieces ingested, which may be explained through naivety and/or ontogenetic shifts in diet. Further investigation in other species and sites are needed to more fully ascertain the role of selectivity in plastic ingestion in this marine vertebrate group.

Tools and constraints in monitoring interactions between marine litter and megafauna: Insights from case studies around the world

Adverse impacts of marine litter is documented on >1400 species, including marine megafauna (fish, birds, sea turtles and mammals). The primary impacts include ingestion and entanglement, and there is increasing concern about chemical contamination via ingestion. Numerous survey approaches and monitoring programs have been developed and implemented around the world. They may aim to provide data about parameters such as species distribution and interactions with anthropogenic activities. During the Sixth International Marine Debris Conference, a session was dedicated to the tools and constraints in monitoring interactions between litter and megafauna. In the present paper, we summarize 7 case studies which discuss entanglement and ingestion including macro- and micro-debris in several taxa and across multiple geographic regions. We then discusses the importance of tools and standardizing methods for assessment and management purposes, in the context of international environmental policies and marine litter strategies.

Assessment of seabed litter in the Northern and Central Adriatic Sea (Mediterranean) over six years

Seabed debris is much less investigated in respect to the sea surface and shores due to sampling difficulties and costs. However, detecting marine benthic litter is fundamental for developing policies aimed at achieving the Good Environmental Status in European Seas by 2020, as requested by the Marine Strategy Framework Directive. This study estimates seafloor litter abundance, composition, spatial distribution and main sources in the North-Central Adriatic Sea (FAO GSA 17) over a six-year period (2011-2016) with 67 stations sampled per year, representing the longest data set for the basin. Litter items collected using a "rapido" trawl were classified in six major categories. The average density of the litter collected over six years was 102.66 ± 41.91 kg/km². The highest concentration of litter was found in stations close to the coast within 30 m depth with a mean weight of 142.90 ± 27.20 kg/km², while the lowest value was recorded between 30 and 50 m of depth (41.12 ± 9.62 kg/km²). Plastic was dominant followed by metal and other litter materials. Lost fishing nets and mussel culture debris accounted for 50% of the overall plastic litter collected. These data and the systematic monitoring of marine litter provide useful information to implement necessary measures to manage marine litter and minimize this type of anthropogenic pollution in the Adriatic region.

Using mussel as a global bioindicator of coastal microplastic pollution

The ubiquity and high bioavailability of microplastics have an unknown risk on the marine environment. Biomonitoring should be used to investigate biotic impacts of microplastic exposure. While many studies have used mussels as indicators for marine microplastic pollution, a robust and clear justification for their selection as indicator species is still lacking. Here, we review published literature from field investigations and laboratory experiments on microplastics in mussels and critically discuss the suitability and challenges of mussels as bioindicator for microplastic pollution. Mussels are suitable bioindicator for microplastic pollution because of their wide distribution, vital ecological niches, susceptibility to microplastic uptake and close connection with marine predators and human health. Field investigations highlight a wide occurrence of microplastics in mussels from all over the world, yet their abundance varies enormously. Problematically, these studies are not comparable due to the lack of a standardized approach, as well as temporal and spatial variability. Interestingly, microplastic abundance in field-collected mussels is closely related to human activity, and there is evidence for a positive and quantitative correlation between microplastics in mussels and surrounding waters. Laboratory studies collectively demonstrate that mussels may be good model organisms in revealing microplastic uptake, accumulation and toxicity. Consequently, we propose the use of mussels as target species to monitor microplastics and call for a uniform, efficient and economical approach that is suitable for a future large-scale monitoring program.

Fishing lines and fish hooks as neglected marine litter: first data on chemical composition, densities, and biological entrapment from a Mediterranean beach

We reported first data on the densities and chemical composition of fishing lines and fish hooks deposited on a Mediterranean beach. On a sampling area of 1.5 ha, we removed a total of 185,028 cm of fishing lines (density 12.34 cm/m²) and 33 hooks (density 22 units/ha). Totally, 637.62 g (42.5 mg/m²) of fishing lines were collected. We sampled 120 items entangled belongings to 7 animal taxa (density 6.49 items/100 m of fishing lines). We also observed a not quantifiable number of egagropiles (Posidonia oceanica spheroids), Rhodophyceae (Halymenia sp.) and segments of reeds of Phragmites communis, trapped in the fishing lines. Fourier transform infrared (FTIR) spectroscopy was used in order to identify the chemical composition of the fishing lines: 92% was made of nylon while 8.0% was determined as fluorocarbon based polymers (polyvinylidene fluoride). Because of their subtlety and reduced size, sandy beach cleaning operations should include at least two consecutive removal samplings: indeed, a part of this litter (12.14%) is not removed in the first sampling. The unexpected high density of fishing lines suggests specific management actions aimed to periodically remove this neglected anthropogenic litter.

Two decades of monitoring in marine debris ingestion in loggerhead sea turtle, Caretta caretta, from the western Mediterranean

Anthropogenic marine debris is one of the major worldwide threats to marine ecosystems. The EU Marine Strategy Framework Directive (MSFD) has established a protocol for data collection on marine debris from the gut contents of the loggerhead sea turtle (Caretta caretta), and for determining assessment values of plastics for Good Environmental Status (GES). GES values are calculated as percent turtles having more than average plastic weight per turtle. In the present study, we quantify marine debris ingestion in 155 loggerhead sea turtles collected in the period 1995-2016 in waters of western Mediterranean (North-east Spain). The study aims (1) to update and standardize debris ingestion data available from this area, (2) to analyse this issue over two decades using Zero-altered (hurdle) models and (3) to provide new data to compare the only GES value available (off Italian waters). The composition of marine debris (occurrence and amounts of different categories) was similar to that found in other studies for the western Mediterranean and their amounts seem not to be an important threat to turtle survival in the region. Model results suggest that, in the study area, (a) period of stranding or capture, (b) turtle size and (c) latitude are significant predictors of anthropogenic debris ingestion (occurrence and amount) in turtles. The GES value for late juvenile turtles (CCL>40 cm) has decreased in the last ten years in the study area, and this is very similar to that obtained in Italian waters. We also provide a GES value for early juvenile turtles (CCL≤40 cm) for the first time. Recommendations arising from this study include ensuring use of (1) the standardized protocol proposed by the MSFD for assessing marine debris ingestion by loggerhead sea turtles and (2) the ecology of the turtles (neritic vs oceanic), rather than their size, to obtain GES values.

Relationships between plastic litter and chemical pollutants on benthic biodiversity

Five Descriptors (D) of Marine Strategy Framework Directive (MSFD): marine litter (D10), non-indigenous species (D2) and organic and inorganic pollutants (D8), were estimated in a coastal area of GSA 16 (Augusta harbour, Central Mediterranean Sea) in order to study their effects on the biodiversity (D1) of the benthic community D6) and to improve data for the MSFD. Investigation of plastic debris had led to the identification of 38 fragments divided into four categories, among which microplastics resulted as the most abundant. Six non-indigenous species, belonging to Polychaeta (Kirkegaardia dorsobranchialis, Notomastus aberans, Pista unibranchia, Pseudonereis anomala, Branchiomma bairdi) and Mollusca (Brachidontes pharaonis) were found. Biodiversity and benthic indices suggested a generalised, slightly disturbed ecological status. Anthracene, Zinc and Chrome were the most abundant chemical compounds in analysed sediments. Significant correlations were found between the abundance of trace elements vs biotic indices and between plastic debris vs biodiversity and benthic indices. This study represents the first report about the abundance of plastic debris and its relationship to contaminants and infauna in Augusta harbour. Our results can provide useful information for national and international laws and directives.

Microplastics in the intestinal tracts of East Asian finless porpoises (Neophocaena asiaeorientalis sunameri) from Yellow Sea and Bohai Sea of China

The direct evidences for the ingestion of microplastics by cetaceans, especially the cetaceans in Asian marine areas are limited. In this study, residue of microplastics in the intestinal tracts of East Asian finless porpoises (Neophocaena asiaeorientalis sunameri) was investigated. Microplastics were detected in all specimens, with mean abundance of 19.1 ± 7.2 items/individual. With respect to microplastics properties, fibers, blue items, and polypropylene were predominant in shapes, colors, and plastic materials, respectively. Trophic transfer and unintentional ingestion might be the potential pathways for microplastics ingested by finless porpoise. The specific intestinal structure might account for the predominance of fibers and the accumulation of microplastics at the beginning portion of intestines. This study indicates that cetaceans in Chinese marine areas also suffer from microplastics pollution. Further studies on the fate and ecological effects of microplastics should be conducted to reveal their potential risks to cetaceans.

First evidence of ingested plastics by a high commercial shrimp species (Plesionika narval) in the eastern Mediterranean

This study provides the first evidence of nylon filament occurrence in the stomach of an economically important target shrimp species in the Mediterranean Sea, Plesionika narval (Fabricius, 1787). Samples were collected monthly from November 2014 to October 2015 from shallow (10-30 m) and deeper waters (150-170 m). The occurrence of plastics in the stomachs of the Narwal shrimp was 5.93% and identified as Nylon by FT-IR analysis. Higher percentages of ingested plastics were found in females from shallower depths and in males from deeper waters. The maximum number of plastics was recorded in January and March, possibly related to the higher feeding intensity of females prior to their reproduction period. A total of 10.3% of females and 4.8% of males with ingested plastics had almost empty stomachs. The presence of plastics in the stomach of P. narval is an evidence of passive ingestion which in this study related to fishing activities.

Spatial distribution of marine litter along italian coastal areas in the Pelagos sanctuary (Ligurian Sea - NW Mediterranean Sea): A focus on natural and urban beaches

Our paper will show data on quantity, typology, distribution of beach litter (Anthropogenic Marine Debris - AMD) within a coastal macroarea surrounding the Pelagos Sanctuary, an International Protected Area in the NW Mediterranean Sea. AMD Monitoring and characterisation have been performed by using SEACleaner Protocol: an adapted version of UNEP/IOC, OSPAR and EU guidelines. 11 beaches located in 5 different areas, have been monitored with a total amount of thirty three surveys, from January 2014 to December 2015, during different seasons. Three kinds of beaches have been considered: Natural (belonging to MPAs), Urbanized and Urban. A total of 34,027 items on a total area of 32,154 m² have been removed and classified. Spatial difference in abundance and composition of AMDs - as well as beach environmental quality - has been detected. Natural sites, and particularly protected areas close to river mouths show a major density compared to other areas.

Plastic ingestion by harbour porpoises Phocoena phocoena in the Netherlands: Establishing a standardised method

Stomach contents of harbour porpoises (Phocoena phocoena) collected in the Netherlands between 2003 and 2013 were inspected for the presence of plastic and other man-made litter. In 654 stomach samples the frequency of occurrence of plastic litter was 7% with less than 0.5% additional presence of non-synthetic man-made litter. However, we show that when a dedicated standard protocol for the detection of litter is followed, a considerably higher percentage (15% of 81 harbour porpoise stomachs from the period 2010-2013) contained plastic litter. Results thus strongly depended on methods used and time period considered. Occurrence of litter in the stomach was correlated to the presence of other non-food remains like stones, shells, bog-wood, etc., suggesting that litter was often ingested accidentally when the animals foraged close to the bottom. Most items were small and were not considered to have had a major health impact. No evident differences in ingestion were found between sexes or age groups, with the exception that neonates contained no litter. Polyethylene and polypropylene were the most common plastic types encountered. Compared to earlier literature on the harbour porpoise and related species, our results suggest higher levels of ingestion of litter. This is largely due to the lack of dedicated protocols to investigate marine litter ingestion in previous studies. Still, the low frequency of ingestion, and minor number and mass of litter items found in harbour porpoises in the relatively polluted southern North Sea indicates that the species is not a strong candidate for annual monitoring of marine litter trends under the EU marine strategy framework directive. However, for longer-term comparisons and regional differences, with proper dedicated protocols applied, the harbour porpoise has specific use in quantifying litter presence in the, for that specific objective, poorly studied benthic marine habitat.

Uptake and effects of the antimicrobial florfenicol, microplastics and their mixtures on freshwater exotic invasive bivalve Corbicula fluminea

Microplastics and antimicrobials are widely spread environmental contaminants and more research on their toxicity is needed. The uptake and effects of the antimicrobial florfenicol, microplastics, and their mixtures on Corbicula fluminea were investigated. Bivalves were exposed for 96h to florfenicol (1.8 and 7.1mg/l), microplastics (0.2 and 0.7mg/l), or mixtures of the two substances. After 96h, all bivalves exposed to antimicrobial treatments had florfenicol in their body (e.g. 2±1μg/g). Microplastics were found in the gut, lumen of the digestive gland, connective tissue, hemolymphatic sinuses, and gills surface of animals. Florfenicol caused a significant inhibition of cholinesterase (ChE) activity (~32%). Animals exposed to 0.2mg/l of microplastics showed ChE activity inhibition (31%), and no other significant alterations. Mixtures caused feeding inhibition (57-83%), significant ChE inhibition (44-57%) and of isocitrate dehydrogenase activity, and increased anti-oxidant enzymes activity and lipid peroxidation levels. Overall, the results indicate that C. fluminea take up florfenicol and microplastics from the water and accumulated or at least retained it in their body for some time; both florfenicol (low ppm range) and microplastics (ppb range) were toxic to C. fluminea, with mixtures containing florfenicol and microplastics being more toxic. Thus, the risk of exposure and toxic effects of florfenicol to C. fluminea and other bivalves, and its predators increase in ecosystems contaminated with the antimicrobial and microplastics, as well as to humans consuming contaminated species from these ecosystems.

Amount and distribution of benthic marine litter along Sardinian fishing grounds (CW Mediterranean Sea)

Reports of marine litter pollution first appeared in scientific literature of the early 1970s; yet, more than 40 years later, no rigorous estimates exist of the amount of litter existing in the marine environment. To cope with this global urgency, this study reports the status of marine litter abundance along fishing grounds surrounding the island of Sardinia (CW Mediterranean Sea; FAO Geographical Sub-Area 11) through three years of trawl surveys. A total of 302 hauls, covering a total of 18.4 km² of trawled surface were carried out in the framework of the MEDITS campaign, at depths comprised between 0 and 800 m. A total of 918 items were collected and sorted, with the highest concentration observed above 200 m depth. Overall, plastic was the dominant component of litter, followed by glass and metal. Comparing our results with other areas from the Mediterranean basin, Sardinian waters showed a lower impact, possibly as a consequence of multiple factors such as the lower human population density and the low flow of the main rivers, among others. In addition, fishermen behaviour with respect to marine litter was investigated by mean of anonymous questionnaires, emphasizing the necessity to further develop management policies and infrastructures supporting litter disposal.

A modeling approach for reposition dynamics of litter composition in coastal areas of the city of Santos, Sao Paulo, Brazil

Given the complexity of the dynamics in litter reposition, our objective was modeling the possible main and interaction effects of tidal oscillations, seasons of the year and the moon phases over the solid waste in Santos beaches. A total of 80 collections were carried out using quadrat sampling, from which we classified, counted and weighed all residue items. We fitted mixed Hurdle models to the output datasets and performed hypotheses tests based on this framework. We found plastic to be the most abundant residue in all seasons, moon phases and tides, followed by Styrofoam and wood. Our models suggest the strongest effect was due to seasonal variations, which, in turn, may be related to different human activities. Although the dynamics of different components showed independency of all interaction structures, plastics depended on the interaction of tide and season, whose impact over estuarine life and ecosystem services shall be further investigated.

Content of Ni, Pb and Zn, in selected elements of ecosystem in three bays in the area of Sevastopol

The aim of the study was to evaluate the content of Ni, Pb and Zn in the water and larvae of fish of the genus Atherinidae L., caught in three bays in the area of Sevastopol. The study was conducted in 2012 in the three bays in the area of Sevastopol: Galubaya, Omega and Karantinna. The results indicate that the content of all elements studied was at a higher level than that observed in the uncontaminated basins. The average concentration of Ni, Pb and Zn in water was respectively: 1.199; 14.62 and 64.32 μg · dm-3. The content of the elements studied in the examined fish larvae Atherinidae ranged from 6.413 to 19.65 mg Ni kg -1, from 1.749 to 5.393 mg Pb kg -1 and from 97.16 to 215.24 mg Zn kg-1.

Community-wide patterns of plastic ingestion in seabirds breeding at French Frigate Shoals, Northwestern Hawaiian Islands

Between 2006 and 2013, we salvaged and necropsied 362 seabird specimens from Tern Island, French Frigate Shoals, Northwestern Hawaiian Islands. Plastic ingestion occurred in 11 of the 16 species sampled (68.75%), representing four orders, seven families, and five foraging guilds: four plunge-divers, two albatrosses, two nocturnal-foraging petrels, two tuna-birds, and one frigatebird. Moreover, we documented the first instance of ingestion in a previously unstudied species: the Brown Booby. Plastic prevalence (percent occurrence) ranged from 0% to 100%, with no significant differences across foraging guilds. However, occurrence was significantly higher in chicks versus adult conspecifics in the Black-footed Albatross, one of the three species where multiple age classes were sampled. While seabirds ingested a variety of plastic (foam, line, sheets), fragments were the most common and numerous type. In albatrosses and storm-petrels, the plastic occurrence in the two stomach chambers (the proventriculus and the ventriculus) was not significantly different.

Plastic ingestion in oceanic-stage loggerhead sea turtles (Caretta caretta) off the North Atlantic subtropical gyre

Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic.

Microplastics pollution after the removal of the Costa Concordia wreck: First evidences from a biomonitoring case study

Microplastics (MPs) represent a matter of growing concern for the marine environment. Their ingestion has been documented in several species worldwide, but the impact of specific anthropogenic activities remains largely unexplored. In this study, MPs were characterized in different benthic fish sampled after 2.5 years of huge engineering operations for the parbuckling project on the Costa Concordia wreck at Giglio Island. Fish collected in proximity of the wreck showed a high ingestion of microplastics compared to both fish from a control area and values reported worldwide. Also the elevated percentage of nylon, polypropylene lines and the presence of polystyrene are quite unusual for marine organisms sampled in natural field conditions, thus supporting the possible relationship of ingested microplastics with maritime operations during wreck removal. On the other hand, the use of transplanted mussels revealed a lower frequency of ingested MPs, and did not discriminate differences between the wreck and the control area. Some variations were observed in terms of typology and size of particles between surface- and bottom-caged mussels highlighting the influence of a different distribution of MPs along the water column. In conclusion, this study demonstrated that MPs pollution in the area of Costa Concordia was more evident on benthonic environment than on seawater column, providing novel insights on the possibility of using appropriate sentinel organisms for monitoring specific anthropogenic sources of MPs pollution in the marine environment.

Seasonal dynamics of marine litter along the Bulgarian Black Sea coast

In this study marine litter (ML) surveys were conducted in 8 beaches along the Bulgarian Black Sea coastline within 4 seasons for 2015-2016. The monitoring applied OSPAR guideline, classifying ML in eight categories and 167 types. The results exhibited predominance of artificial polymer materials - 84.3%. ML densities ranged from 0.0587±0.005 to 0.1343±0.008 n/m², highest on the urban beaches. The seasonal dynamics of most top 10 ML showed highest quantities in summer than the other seasons, as the differences are of high statistical significance (0.001≤P≤0.05). Top 1 ML item for most of the beaches was cigarette butts and filters reaching 1008±10.58 nos. in summer and from 19±3.41 to 89±7.81 nos. during the rest of the seasons (P<0.001). For the pronounced seasonality contributed the recreational activities, increased tourist flow and the wild camping. The investigation will enrich data scarcity for Descriptor 10 "Marine litter".