Proceedings of the International Conference on Microplastic Pollution in the Mediterranean Sea

The Mediterranean Sea is one of the most polluted areas of the world with regard to microplastics. However, detailed knowledge about the spatial variability in microplastics abundance and composition is lacking. We present here the result of a large-scale survey of microplastic pollution in Mediterranean surface waters, demonstrating sub-basin scale heterogeneity in the abundance and in the polymeric composition of these floating particles, which is likely the ultimate result of a complex interplay between pollution sources, sinks and residence times of different polymers at sea.

Mediterranean sea is one of the most sampled areas for floating microplastics (MPs). However, only few investigations have been conducted at small spatial and temporal scales in coastal areas. To fill this gap, MPs (< 5 mm) were collected off the mouth of two contrasted rivers: the Rhône River, the largest source of freshwater and sediments into the Mediterranean Sea, and a typical small Mediterranean coastal river, the Têt River. Close surface seawater transects were performed using a manta trawl (>300 μm), at different seasons in the Rhone area and every month during one year in the Têt area. After removal of organic matter, MPs were examined under a dissecting stereo microscope. Preliminary results show highly variable MP concentrations even at small scale. Indeed, concentrations ranged from 0.05 to 0.6 items.m−3 for the Têt area with an average of 0.2 items.m−3 and from 0.1 to 0.5 items.m−3 with an average of 0.3 items.m−3 for the Rhône area. Concentrations can change by a factor of 4 between two consecutive days at the same location and by a factor of 3 between two consecutive trawls on the same day. Fibers are the most abundant shape (40–90%), followed by fragments (0–50%). Foams and films are less represented (0–20%). FTIR analysis indicates that fragments and films were mostly polyethylene (PE) and polypropylene (PP), while foams were essentially made of polystyrene (PS). Fiber analysis is ongoing. Occasional presence of lint composed of hundreds of fibers can partly explain the high differences observed at small scales, as well as fast changing river inputs. These extended observations of floating MPS in the NW Mediterranean coastal environment underlines the necessity of performing replicate sampling to get a better insight into the spatial and temporal distribution patterns of these worrying pollutants.

Microplastics have become a more and more dominant threat to marine ecosystems. The ubiquity of microplastics is one of the major problems; from the sea surface and water column to the beach and seabed sediment or even ingested by marine organisms, small plastic particles have been found. This study is focused on monitoring and assessment of microplastic pollution (plastic particles <5 mm) on the sea surface, in beach sediments, and in marine biota in the Corfu Island area (Northern Ionian Sea). Microplastics detected in samples from water, sediment, fish gut or mussel tissue were stereoscopically observed, categorized by shape, size, colour and their polymer type was identified by FTIR analysis. Microplastic items in sea surface water ranged from 0 to 1.61 particles/m2. Microplastics average abundance in beach sediments ranged from 17 to 95 items/m2. Out of all fish and mussels tested, the percentage of individuals detected with microplastics was 41.25% and 46.25% respectively. The average abundance of small microplastics (<1 mm) in positive fish and mussels was 1.66 particles/fish and 1.83 particles/mussel, while the no large microplastic (1–5 mm) was detected. The majority of microplastics in all environmental compartments were identified as polyethylene. Relations in size classes and polymer type among environmental compartments are investigated. Results describe a holistic image of the pollution caused by microplastics in the study area and can be useful for an integrated microplastic monitoring.

TARA-Mediterranean expedition crossed the entire Mediterranean Sea in 2014 to study the distribution and concentration of floating microplastics and zooplankton. Surface samples were collected with a 330 µm Manta net, plastics were sorted from 124 samples and digitally imaged with the ZoosCan system. Results showed that plastic fragments were present in all samples with an average of 2.6 x 105 items/km2 and values varying from 2 x 103 items/km2 in the Eastern basin, to more than 2 x 106 items/km2 in the Western basin. Coastal zones of Naples, Corsica and Marseille were clearly identified as areas of particularly high plastic concentration.

Since the 1950s plastic production has exponentially increased. Different expeditions have sampled microplastics in all the world’s oceans in order to better know this pollution. However, a large amount of plastic particles is collected during all campaigns, such as during the Tara Mediterranean Sea campaign. And, methods developed to analyse them are time-consuming. So, how to work to chemically characterize samples from large libraries?

A new 2D Lagrangian tracking model with the stochastic representations of beaching and sedimentation of the plastic has been developed. Copernicus Marine Environment Monitoring Service is used as a source of high-resolution datasets on the Mediterranean currents and Stokes drift components. Virtual floating particles are released everyday from the realistic Mediterranean inputs and tracked over 2013–2017, encompassing an overall particle ensemble of ~107 members. Preliminary results show: (1) the pronounced mesoscale dynamics at the sea surface; (2) the elevated abundance of the virtual particles on the coastlines and at the bottom of the Cilician Basin (NE Levantine) and the Catalan Sea sub-basin.

Raw materials used for the fabrication of plastic products, namely pellets or nurdles are an important source of microplastics dispersed in the marine environment. They can reach the environment for accidental loss during transportation or as result of an improper handling.

Wastewater treatment plants (WWTIP) are a potential source of microplastics [1,2]. Several types of microplastics, namely microbeads, fibres and fragments, were analysed in two WWTP effluent serving different Portuguese communities. A bigger station treating mixed domestic and industrial wastewater averaging 18000 m day and a smaller station with treating mostly domestic wastewater averaging 7250 m day. A total of 6065 microplastics were observed in 5,5 litres of wastewater sampled. 90% of the microplastics analysed were fragments and 88% were collected from treated effluent (1687 items in average per litre). Fibres presented a higher percentage in the affluent (88%), comparing to treated effluent (12%). Regarding sizes, microplastics with less than 0, 5 mm were the most representative in both WWTP. Fibres with 1 to 2 mm were more common. This study intends to contribute with a standardized methodology to analyse microplastics in wastewater, from sampling to identification, measuring and handling processes in the laboratory.

As plastic particles are one of the most commonly waste found on beaches [1], this pollution requires the use of innovative extraction methodologies especially for smallest size ranges of plastic particles, as microplastics.

Microplastic particles from laundry wastewater have been encountered into the marine environment. MERMAIDS project has demonstrated evidence on microplastic fibers release in laundry processes, to select and study different types of commercial textile auxiliaries and detergent additives with potential to reduce the fibre breakage and avoid the loss of microfibres during laundry.

Contamination of the aquatic ecosystem by microplastic is a growing worldwide problem. Sewage from textile laundry has been identified as a potentially important source of synthetic fragments in the environment; field studies registered synthetic textile fibers in ocean and freshwater samples as well as in sediments.

Recent estimates indicate that 10% of total plastic waste ends up in the oceans and have reached even remote areas such as polar region. Depending on the chemical composition of plastic polymers, these wastes can accumulate on the seabed (about 70%) or remain suspended in the water column.

Microplastics (MPs) are among major micropollutants (<5 mm) which can be found in water sources and air in substantial quantities and which still are not covered by standard sorting and analysis procedures.

The use of disposable plastic bags, one of the leading plastic products encountered in daily life, has been mostly impossible to prevent, even though a falling trend is observed in light of taxes and fines introduced in a number of countries. The term microplastics often recalls the break of larger plastics into smaller “plastic fragments.” Yet, “MP fibers” which are severed apart from synthetic textiles and “MP films” which are produced as plastic bags crumble away in time should also come to one’s mind. The smaller the size of a plastic, the larger the number and range of species it could affect and harm. In terms of volume, microplastic fibers and films are particularly smaller, lighter, and less voluminous compared to “plastic fragments.”

Southeast Asia harbours the highest marine diversity of our planet. At the same time, the countries in the so-called Coral Triangle (CT; Fig. 1) have the highest potential/risk of plastic pollution to the marine environment. Biodiversity research is still struggling with the sheer inventory of biota, as many marine organisms already are under risk of becoming extinct by human influence.

Because of their abundance, persistence, and ubiquity, microplastics (MPs) represent a serious environmental risk, recognized even by the European Union which calls for further investigation. The Mediterranean basin seems to be highly affected by microplastic pollution, and it has been considered the sixth great accumulation area for marine litter.

Marine litter such as microplastics pose a variety of problems once they reach the environment via improper waste disposal or spills, among others. While microplastics are often ingested by marine organisms, marine life is not only threatened by the physical damage plastic items can cause but also by the possible chemical pollution resulting from the leaching of plastic additives or other adsorbed chemicals on the plastics surface during long-range transport. Plastic additives include plasticizers, flame retardants and colour pigments. The demonstrated toxicity of some of these molecules has led to national and international legislations limiting or banning their use. However, a wide variety of substances are still found in plastic products and little is known about their impact on the marine and terrestrial environment.

Microplastic ingestion has been reported by a range of marine fish species, but less known is the level of microplastic contamination by fish species from transitional ecosystems such as estuaries. The aim of this study was to assess the ingestion of microplastics by three important commercial fish species: the sea bass (Dicentrarchus labrax), the commom two-banded seabream (Diplodus vulgaris) and the European flounder (Platichthys flesus) from the Mondego estuary (Portugal). Microplastics were extracted from the gastrointestinal tract of 120 individuals after a digestion solution (10% KOH). A total of 157 microplastics were extracted from the total fish (96% fibers and 4% fragments), with 1.67 ± 0.27 (SD) microplastics per fish. The main plastic polymers identified by μ-FTIR were polyethylene, polypropylene, rayon, polyester, polyacrylonitrile and nylon.

Plastic is widely used in everyday life being one of the more versatile materials ever produced. The rising demand of plastic items to support the societal development has dramatically boosted the annual plastic production from 1.5 in the 1950s to 311 million tonnes in 2014 (PlasticEurope in Plastic-the Facts 2015: an analysis of European plastic production, demand, and waste data, 2014). The dark side of the plastic revolution is the marine pollution, with an estimated amount of 9.5 million tonnes of new plastic waste flowing into the oceans each year (Boucher and Friot in Primary microplastics in the oceans: a global evaluation of sources. IUCN, Gland, p. 43, 2017).

Over 5.25 trillion particles of plastic have spread throughout the worlds’ oceans. The size frequency distribution of plastic particles is thought to be basically uniform across the major oceans. However little is presently known of the plastics finding their way into the remote Southern Ocean. We gathered information on the size frequencies of plastic debris in the range 2–10 mm by surveying a beach and collecting scats from fur seals, a known fish predator, at Sub-Antarctic Macquarie Island. The results show differences in the frequency distributions between the two sampling platforms. Accidental ingestion of plastic particles by Myctophid fish might be a sink for small plastic particles.

Examination of the digestive tracts of two species of siganids (rabbitfish), collected in 2016 in the Mediterranean coastal waters of Israel, for the presence of microplastics (MP) revealed that 92% of the 88 fish examined had consumed between 1 and >500 MP per fish. A comparison of the gut contents of fish that had been collected from the 1960s to the present time showed that there was a temporal increase in the proportion of fish with MP, from ~10% in 1960–1970; ~80% in the 1990s; 92% in 2016. There was also a temporal change in the proportion of MP types ingested by these fish. Siganids may be valuable bioindicators of MP pollution in the sea.

Much attention has been paid in recent years to the fate of microplastics in the environment. Several studies have shown that microplastics can be taken up by a variety of organisms (e.g., fish, mussels, zooplankton, sea urchin, birds) and thus can cause adverse effects such as death due to ingestion and entanglement, as well as pro-inflammatory responses.

The existence of microplastic particles (polymer particles <5 mm) in our environment has already been proven by several studies [Cole et al. in JAMA 62:2588–2597, 2011, Cózar et al. in JAMA 28:10239–10244, 2014].

Plastic debris represents a significant problem among the various problems facing the marine environment. In this work, we aim to explore the ability of two marine indigenous communities to degrade secondary microplastics. Polyethylene (low-density as well as high-density polyethylene) films were exposed to UV radiation until they were fragmented to microplastics under mild mechanical stress. Next, 50mg of sterile microplastics with size 2 mm–250 μm was added into sterile flasks and was incubated separately with these two pelagic microbiomes. A significant decrease in the weight of microplastics was determined along the experimental period, implying the potential ability of indigenous communities to in situ degrade secondary microplastics. Moreover, the protein content marginally decreased while carbohydrate content of both treatments increased at this time interval. Accordingly, the populations increased along experimental period.

In the process of becoming independent from fossil hydrocarbon resources bio-based plastic is one option, being also favoured by programmes of the European Commission. To achieve maximum sustainability bio-based polymers that are also biodegradable are entering the market, with nationally differing regulation. It is wise to assess the risk of these new materials especially in fields where their use is intrinsically linked to a loss to the environment (e.g. by conversion to micro-plastics through wear), or where unintentional littering is probable. Thus, standard tests (e.g. ISO) are needed to validate the claim of a material being “biodegradable” for consumer safety and environmental impact. Here we give an overview of current marine standard tests and present results from the EU-funded project Open-Bio on the development of tests of biodegradability under marine conditions. We present feasible field test systems for three coastal scenarios: plastic being buried in intertidal beach sand (eulittoral test), plastic floating in the shallow water column (pelagic test) and plastic sunken to the sandy sublittoral (benthic test). The field tests were optimized to a state that the test material could be observed in situ over a time of up to 2 years without loss of larger fragments, and marine disintegration could be followed for common biodegradable polymers. Degradation rates for the tested polymers are given. A set of mesocosm experiments simulating the same three habitats supported the field research in a semi-controlled setting of environmental conditions, and allowed to critically evaluate field and lab test results, leading to an environmentally relevant test scheme. Our outlook shows the next steps of test development needed to provide a comprehensive toolset to cover the majority of conditions in which plastic is found in the marine realm.

Biodegradable plastic is gaining attention, also through market regulation by a growing number of countries. The substitution of conventional plastic by these new materials is discussed as one mitigation measure to the ever-growing global problem of marine plastic litter. Modelling showed that the estimated substitution potential on a global scale might be small, with a contribution of only 0.3% to the total marine debris. However, there are huge potentials for substitution on local level, and for single plastic items and applications of one single polymer. In order to assess the environmental risk of new materials such as biodegradable plastics being introduced to the market and potentially also lost to the environment, in-situ studies of the performance under marine conditions have been conducted. Two studies in the Mediterranean Sea are summarized and the role of biofilm formation and fouling on disintegration are highlighted. Preliminary results of ongoing studies in tropical SE Asia are presented.

Active packaging refers to packaging systems with active functions beyond the inert passive containment and protection of the product. It is commonly used with foods, as it helps extend shelf life, improve safety or sensory properties and maintain food quality (Vermeiren et al. in Trends Food Sci Technol 10:77–86, 2009). Most diffused active packaging systems include the use of oxygen scavengers, carbon dioxide or ethylene emitters and scavengers, ethanol releaser, as well as antimicrobial and antioxidant agents. The active agent may be placed in the package with the food, within a small sachet or pad of permeable material, able to release volatile antimicrobial agents without allowing a direct contact with the food product.

This study aims to investigate the degradation of biodegradable polymers such as poly(lactic acid) (PLA) and polycaprolactone (PCL), polyhydroxybutyrate (PHB) and polybutylene succinate adipate (PBSA) buried in sand, to verify the behaviour of these polymers in habitat where plastic waste can be stranded when carried by the sea.

Sargassum algae are brown free-floating seaweed found worldwide in temperate and tropical regions and provide shelter and food for many animal species. In recent years, their wide-spread presence has gone out of control, leaving dense clumps of rotting weeds and toxic waste along urban beaches. Nevertheless, this harmful brown seaweed is a valid source of sodium alginate (SA), a well-known biodegradable and biocompatible polysaccharide, widely used in food, pharmaceutical and biomedical applications due to its stabilizing and gelling properties. The aim of this paper was the extraction and chemico-physical characterization of sodium alginate from Sargassum seaweeds wastes by using unconventional ultrasound method.

The washing processes of synthetic clothes have been lately identified as a main source of microplastic pollution in marine environment. During a common washing process, synthetic fabrics undergo mechanical and chemical stresses that induce the detachment of microfibers from the main yarns. Such microfragments remain in the wastewater, eventually reaching marine ecosystems where they represent a serious threat for the flora and fauna. A possible solution that could mitigate such source of microplastic pollution is the application of functional finishing treatments able to protect fabrics during washings, reducing the amount of microfibres released. The present work proposes an innovative finishing treatment of polyamide fabrics by using pectin, a natural polysaccharide extracted from fruits. Pectin was chemically modified by reaction with glycidyl methacrylate (GMA), whose vinylic groups were exploited to graft pectin on the surface of the polyamide fabric, creating a coating on the fibres. The effectiveness of the surface treatment was assessed by using the following characterization techniques: scanning electron microscopy (SEM), solid-state nuclear magnetic resonance spectroscopy (NMR) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Furthermore, washing tests of untreated and treated fabrics were carried out to assess the release of microplastics. The washing effluents were filtered and the filters were analysed by SEM to evaluate the amount of microfibres released. The obtained results showed that the application of the pectin-based coating, could reach a reduction of more than 80% of the number of microplastics released by untreated polyamide fabrics during a domestic washing process.

Until today, many studies (Hidalgo-Ruz and Gutow et al. in Environ SciTechnol 46:3060–3075, 2012; Auta et al. in Environ Int 102:165–176, 2017) were focused on the origin or the formation mechanisms of microplastics. Microplastics comprise a very heterogeneous group of fragments that vary in size, shape, color, specific density, chemical composition, and other characteristics.

Polymer nanocomposites of conductive polymer, polyaniline (PANI) with multi-walled carbon nanotubes (MWCNTs), have gained a great interest for their application in environmental and water quality monitoring (where pH value becomes one of the reliable data). Compared to the inorganic counterparts, conducting polymers have advantage in achieving high sensitivity and selectivity by virtue of their chemical and structural diversity. In the framework of FP7 project COMMON SENSE (OCEAN 2013.2-614155), screen-printed electrodes as a pH nanosensors based on nanocomposites of conductive polymer matrix-PANI and MWCNT were prepared by electrochemical polymerization. Characterization was performed by several spectroscopic techniques and electrical measurements. Electrochemical synthesis of the PANI-based composites was performed at 0.75 V vs. saturated calomel electrode (SCE) for 40 and 60 minutes. The working conditions were determined using electrochemical steady-state polarization measurements. Morphology of the produced composites was observed using scanning electron microscope (SEM), structural characteristics were studied using Raman spectroscopy, while thermal stability was determined using thermal gravimetric analysis (TGA/DTA). The results point out on fibrous and porous structure of PANI-based composites, with strong interaction between quinoidal structure of PANI with carbon nanostructures via p–p stacking according to Raman spectroscopy measurements. TGA coupled with DTA showed the increased thermal stability of the studied composites. The obtained nanocomposites exhibited a high value of conductivity which attributed to the synergy effect of the conductive polymer matrix and carbon nanostructure. Resistivity (i.e., conductivity) changes were measured at different pHs (4 to 10) as well as in different marine regions.

The rapid industrial development and urbanization have intensified environmental pollution and caused deterioration of ecosystems by accumulation of many pollutants, especially heavy metals. Most of the heavy metals are toxic, and their ions are not biodegradable with the tendency to accumulate in the soil, water resources and the living organisms; hence, they are significant environmental pollutants. Therefore, the treatment of the heavy metal ions and their elimination from water and wastewater is very important for environmental protection and thus the public health. In the frame of this work, the adsorption abilities of natural and nanosorbents, particularly natural peanut husks, expanded perlite and graphene, to remove Ni(II), Pb(II), and Fe(II) ions from water systems, were investigated. The influence of the pH (4–8) of the solution, the amount of adsorbent (0.5–5.5 g/l), the initial metal ion concentration (0.3–2.0 mg/l), and the contact time (5–180 min.) on the efficiency of removal of metal ions was investigated. Thus, the optimal conditions for achieving maximal effectiveness for heavy metals removal were determined. The characterization of the sorbents was performed utilizing the following techniques: SEM and TGA. Adsorption equilibrium of the systems was analyzed using the following isotherms: Langmuir, Freundlich, Langmuir–Freundlich, and Redlich–Peterson. The maximal adsorption capacity of the peanut husks, perlite and graphene for Ni(II), Fe(II), Pb(II) was obtained, and the percentage of removal was determined. A comparative analysis for the efficiency of all used sorbents for Ni(II), Pb(II), and Fe(II) ions removal from the three component systems was conducted at the end. The expanded perlite gave the best results for the removal of Ni (II) and Pb (II) ions, while graphene proved to be excellent adsorbent for Fe(II) ions with an efficiency of 100%.

The sources of microplastics in the oceans—and in the Mediterranean Sea—are multiple. One of the sources are microplastics that are added to cosmetic products. Several states have adopted national bans on microplastics in rinse-off products. Before EU regulation might accomodate a ban on microplastics in cosmetics, the REACH Regulation has to be amended to include the registration, evaluation and, if necessary, restrict the use of polymers as chemical substance in certain products. Informing consumers about microplastics in cosmetic products, for example by labelling, remains essential as long as there is no ban on microplastics.