Marine litter in sediments related to ecological features in impacted sites and marine protected areas (Croatia)

Assessment of microplastic abundance and impact on recreational beaches along the western Algerian coastline

Microplastics (MPs) have attracted global attention due to their ubiquity and potential impact on the environment. However, MPs are poorly documented along the Algerian coast. To address this data gap, this study investigated the presence of MPs on three recreational beaches in western Algeria (Stidia, Sablettes and Mersat El Hadjaj). The mean MP abundance for the three beaches was estimated at 55.47 ± 48.01 items/m2. Characterization of MPs shape revealed that fragments (79.81 %) were dominant, followed by pellets (10.58 %), filaments (5.57 %), and foam (3.85 %). An assessment of the Microplastic Pollution Index, the Pellet Pollution Index, and the Coefficient of Microplastic Impact, revealed the presence of very low to moderate levels of MPs on the beaches. This presence was associated with minimal beach pollution and moderate overall impact. The sector analysis approach results confirm that there are two different magnitudes of MPs presence that can negatively impact on the environmental quality of the studied beaches.

Microplastics in the sediments along the eastern Arabian Sea shelf: Distribution, governing factors and risk assessment

Despite the omnipresence of microplastics (MPs), the studies around the western continental shelf of Indian Ocean (Eastern Arabian Sea-EAS) are uncovered and understudied. Thus, the present study was focused to understand the spatial distribution, characterization and risk assessment of MPs in sediment across seven coastal transects (10 to 50 m) all along the EAS shelf. The highest MPs concentration (MPs/kg d.w.) was detected in the northern EAS (NEAS; 2260 ± 1050) followed by central (CEAS; 1550 ± 1012) and southern (SEAS; 1300 ± 513) shelves. Among all distinct locations, the highest concentration of MPs (2500 ± 1042) was detected in the north coastal sediments off Mumbai, followed by off Mangalore (1480 ± 1169) in the center and off Kochi (1350 ± 212) in the south. MPs were found in the form of fibres, fragments and films with a predominance of fibres (~70-80 %). Approximately 74.6 % of the total MPs were in the size range of 300 μm to 5 mm. The surface of detected MPs was rough, irregular, and mechanical weathering features such as pits, grooves also observed and spotted with bacterial community structures. Polypropylene (PP; 34 %), polyisoprene (PIP; 19 %), butyl rubber (18 %), and low-density polyethylene (LDPE; 13 %) were dominant polymers. The pollution load index highlighted minor risk while the polymer hazard index exhibited a hazard level of V. Litter discharge, fishing activities, and active marine navigation are among the many high-risk sources of plastic contamination in this region. Due to the prevailing winds, currents, low sea surface height, and high precipitation, the conditions in the EAS are favorable for the accumulation of both sea-based and land-based particles. Hence, this study provides novel insights into the potential risks posed by MP to the IO rim and associated marine ecosystem which will enhance our knowledge of the ecological implications and consequences of MP pollution, ultimately aiding in developing effective management and mitigation strategies.

The hyperbenthic environment: A forgotten habitat for plastic pollution

This study investigates the abundances and composition of microplastics (MP) among the shallow layers of a coastal Mediterranean Marine Protected Area (Cabrera MPA), seafloor sediments, hyperbenthic environment, and the water column. The mid waters samples were collected mid-way between the sea surface and the seafloor and hyperbenthic samples at the water layer adjacent to the seafloor. Sampling was carried out on patchiness seafloor of Posidonia oceanica meadows. The seafloor sediments showed a mean abundance of 378,769.20 ± 508,109.11 MPs/m3, three orders of magnitude higher than the hyperbenthic (209.17 ± 117.07 MPs/m3), and the mid waters layer (106.48 ± 107.17 MPs/m3). An increasing vertical gradient in MP abundances, mainly composed of fibers was observed. Fibers were made-up mainly of polystyrene (PS, 25 %), expanded polystyrene (EPS, 18 %) and cellulose acetate (CA, 16 %). The results stress the need to increase efforts to find solutions to mitigate fiber pollution in the marine environment.

Rajids ovipositing on marine litter: A potential threat to their survival

Marine litter is a complex environmental issue threatening the well-being of multiple organisms. In the present study, we present an overlooked pathway by which marine litter interaction with certain ovigerous skates (Family: Rajidae) communities could compromise their survival. We propose that skates from the genus Sympterygia deposit their egg capsules on marine litter substrates by accident, which are then washed ashore still unhatched. We conducted 10 monitoring surveys on three beaches of La Libertad Region, on the north coast of Peru, looking for marine litter conglomerates to determine the presence of egg capsules. We registered a total of 75 marine litter conglomerates, containing 1595 egg capsules, out of which only 15.9 % were presumably hatched, and 15.8 % were still fresh. Fishing materials were identified as the main item in marine litter conglomerates. We conclude that this behavior could contribute to the decline of Sympterygia communities, although further research is needed.

Chemical pollution and ecotoxicological effects of high-density polyethylene microplastics in Mytilus galloprovincialis from two Italian lagoon ecosystems

Transitional water ecosystems have low water exchanges and can trap chemicals and microplastics (MPs). In this study, MPs, trace elements, polycyclic aromatic hydrocarbon-PHAs levels and the oxidative stress response were assessed in Mytilus galloprovincialis from two Italian lagoon ecosystems (Orbetello and Varano). In addition, the ecotoxicological effects induced by the exposure of M. galloprovincialis to high-density polyethylene-HDPE MPs were also determined. Levels of trace elements were almost always comparable among the sites, whereas MPs were found only in mussels from Orbetello. PAHs were always under the limit of quantification. Glutathione peroxidase and malondialdehyde levels were significantly higher in mussels from Varano. As regard the exposure test, it was found a significant effect of treatment, site and their interaction on mortality and biochemical biomarkers in both fed and unfed mussels. However, principal component analysis suggests similar effects of both color and nourishment condition on biochemical biomarkers. These findings warrant further investigation.

First assessment of microplastics in offshore sediments along the Lebanese coast, South-Eastern Mediterranean

Few studies on microplastics (MPs) in the marine environment have been conducted along the Eastern part of the Mediterranean Sea and even fewer along the Lebanese coast. This study aims to determine MPs contamination for the first-time in coastal and continental shelf sediments collected along the Lebanese shores, South-Eastern Mediterranean Sea. Sediments were collected as transects in 10 sites with a total of 23 samples between 2 and 120 m depth and suspected MPs were assessed by moving farther from land-based sources. Microplastics concentrations ranged between 0 and 4500 MPs/kg of dry sediment (1126 ± 1363 MPs/kg). Polypropylene, polyethylene, polyethylene terephthalate and polystyrene were the polymers identified on micro-Raman. Coastal landfills and raw sewage effluents were identified as the main sources and routes for MPs into the Lebanese coastal marine environment. This study serves as the first database reporting MPs in continental shelf sediments in the South-Eastern Mediterranean.

Characterization and distribution of plastic particles along Alexandria beaches, Mediterranean Coast of Egypt, using microscopy and thermal analysis techniques

Microplastics (MPs) contamination has become a global concern with potential impacts on the marine environment. Alexandria is the second-largest city in Egypt and a significant contributor of plastic litter inputs into the Eastern Mediterranean Sea. The current study provides an in-depth analysis of the plastic particles accumulated along Alexandria beaches. Types, composition, and potential sources of MPs were investigated using microscopy and thermal analysis. A mean value of 389.1 ± 285.9 items kg^-1 dry weight was detected in the shore sediments similar to other records from the Eastern Mediterranean region. An average of 457.4 ± 281.8 items m^-3 was recorded in the surface water, which was the highest recorded MPs density in onshore waters of the Mediterranean region. Thermogravimetric analysis (TGA) showed that plastics made up 0.5% - 72% of the materials extracted from the sediment samples, and 0.58% - 20.6% from the water samples. Differential scanning calorimetry (DSC) identified ten semi-crystalline polymers. Low-density polyethylene (LDPE) and polyethylene vinyl acetate (PEVA) were the common polymers. The single-use plastic bags and detergents were the land-based sources of marine plastic litter. The sea-based sources included antifouling paints, maintenance of ships, and abandoned fishing gears. Proper management plans of domestic waste input, polluter-pay strategy, and education programs aiming at the Fishermen and how plastic pollution would impact their livelihood are urgently needed.

First evidence of plastic pollution in beach sediments of the Skikda coast (northeast of Algeria)

This study is the first attempt to provide original data on plastics debris occurrence in beach sediments of the Gulf of Skikda in Algeria (southwestern Mediterranean). Sediment samples from seven beaches were collected to extract, quantify and characterize mesoplastics and microplastics. Particles were classified by size into mesoplastics (5-25 mm) and large microplastics (1-5 mm). Overall, microplastics were the most abundant size fraction in terms of number of items. The average mass of mesoplastics was twice that of microplastics, revealing a notable reservoir of plastics that is scarcely ever reported in the literature. The predominant types were fragments and pellets, white/transparent in color. The average concentrations of total plastic were 1067.19 ± 625.62 items/m², 106.98 ± 62.39 items/kg, and 50.65 ± 9.82 g/m², showing variability between beaches and within sampling sites. Thus, the Skikda coast has high levels of pollution compared to other areas of the Mediterranean Sea.

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.

Distribution and environmental risk assessment of microplastics in continental shelf sediments in the southern East China Sea: A high-spatial-resolution survey

We report a high-spatial-resolution study on the distributions, characteristics, and environmental risks of microplastics in surface sediments of the southern East China Sea. Microplastics were omnipresent in the sediments (concentration range: 53.3-246.7; mean: 138.4 particles/kg dry-weight sediment) and enriched in nearshore areas close to urban centers relative to lower offshore concentrations. The microplastics identified were dominated by polyethylene (41.2%) and polyethylene terephthalate (19.9%) in polymer type, fibers (45.8%) and fragments (40.3%) in shape, 0.1-0.5 mm (61.0%) in size, and black (52.0%) in color. The benthic environment experienced low to moderate microplastic pollution, with polyvinylchloride exhibiting the highest ecological risk index. The high-resolution sampling revealed highly diverse polymer types and strongly patchy distributions of microplastic abundance and pollution indices in sediments. Results from this study imply that complex physical, biological, and topographic interactions control the distribution of microplastics and the associated environmental risks in coastal sediments.

Distribution and characterization of microplastics in marine sediments from the Montenegrin coast

PURPOSE

Plastic pollution in the world has led to an abundance of microplastics (MPs) and has been identified as a potential factor that can lead to serious environmental problems, especially in oceans and seas. Information on the current status of MPs pollution along the Montenegrin coast is insufficiently investigated. This study monitors the abundance, distribution, and sources of MPs, and identifies present polymers in the surface sediment of the Montenegrin coast, as well as comparison with previous research.

MATERIALS AND METHODS

Ten sampling sites along the Montenegrin coast were selected to collect surface sediment samples. The upper layer of sediment (0-5 cm) was collected by a Petite ponar grab. The samples were dried, and density separation was performed using a NaCl solution. The abundance and morphological characteristics of MPs were determined using an optical microscope (DP-Soft software), while FT-IR analysis was done to identify the polymer type.

RESULTS AND DISCUSSION

Microplastics were identified in all sediment samples with an average abundance of 307 ± 133 (SD) MPs/kg in dry sediment. The highest abundance of MPs was found in locations in the vicinity of highly populated areas, near wastewater discharges, and areas with high fishing and tourist activities. The most dominant shape types of MPs in all samples were filaments and fragments. The most common colors of MPs were blue and red, while the dominant MPs sizes were 0.1-0.5 mm and 0.5-1.0 mm. Of the eight identified polymers, PP, PE, and PET were the most common.

CONCLUSION

This study reveals MPs characteristics (abundance, distribution, shape type, colors, size, polymers type) in surface sediment along the Montenegrin coast, as well as the most significant sources of MPs pollution, and provides important data for further research on MPs to identify the effects of MPs pollution on the quality, health, and functionality of the marine environment.

Marine debris knows no boundaries: Characteristics of debris accumulation in marine protected areas of the Florida Keys

Marine debris is a persistent and pervasive threat worldwide including inside marine protected areas (MPAs). To assess marine debris accumulation rates and potential impacts, we counted and evaluated trap, non-trap fishing gear, and non-fishing debris in unprotected areas and MPAs with different management boundary regulations in the Florida Keys (USA). Analyses identified that neither MPA type nor size were strong drivers of debris density and that debris densities were not statistically different between unprotected areas and MPAs. Non-fishing and non-trap fishing gear debris densities were potentially related to unexplored local differences in human behavior, while trap debris density was likely associated with oceanographic forces that transported traps into the MPAs. Overall, our results suggested that the drivers of marine debris accumulation for each debris category were different and may vary with each individual MPA, and that marine debris is not constrained by MPA boundaries.

Microplastics in Surface Sediments along the Montenegrin Coast, Adriatic Sea: Types, Occurrence, and Distribution

Considering that microplastics are widespread in the marine environment, in this study we evaluated the presence, identify distribution, abundance, shape type, and color of microplastics in surface sediment along the Montenegrin coast, on the Adriatic Sea. These preliminary results provide the first published record of microplastics found in the surface sediment of this area and highlight the importance of microplastics as a component of marine debris. We documented the presence of microplastics at all sampling locations. The identification of polymer types was performed using Fourier-transform infrared (FTIR) spectroscopy, whereby the presence of three polymer types became evident: polypropylene (54.5%), polyethylene (9.7%), and acrylate copolymer (2.0%). Another 22.2% of particles were unidentified polymers, and the remaining 11.5% were non-synthetic materials. The most common shape type of microplastics was filaments (55.5%), followed by granules (26.3%), fragments (14.9%), and films (3.3%). The dominant colors of microplastics followed the order: blue > yellow > red > clear > black > green > blue-white > white. The average abundance of microplastics in all sampling locations was 609 pieces of microplastic/kg of dry sediment. Compared with other studies, the surface sediment of the Montenegrin coast is moderately to highly polluted with microplastics, depending on the examined location.

Seafloor litter along the Italian coastal zone: An integrated approach to identify sources of marine litter

A heterogeneous amount of waste of different origins is continuously generated along Italian coasts in the Mediterranean Sea. In this paper, using information regarding the quantities and the different types of marine litter based on Project AWARE's "Dive Against Debris" data, we try to identify the main sources of this waste. In particular, the methodological approach used associates the origin of marine litter sources with the dataset of geo-localised state-owned maritime concessions, which are loaded by the granting bodies (regions, municipalities, port authorities) on the State Property Information System (Sid). The sources of marine litter were evaluated using the matrix scoring technique (MST). Then, to assess the weight of each source in each station, the community-level weighted mean (CWM) was calculated. Single-use plastic accounted for the highest percentage (19.13%), followed by glass beverage bottles (10.90%), shopping bags (9.03%), aluminium beverage cans (4.91%), and cigarette butts (4.61%). Tourism and beach users contributed to 42.3% of the litter found, followed by fishing (15.7%) and yachting (11.3%). The overlapping of the data collected by scuba divers with the state concessions of activities from offshore and mainland areas was used to distinguish the anthropic pressures that impact the coast. Policy makers and the local administrator may use these results to define new methods of collection and reuse of anthropic waste through a more harmonised approach in the management of marine waste.

A critical review on marine litter in the Adriatic Sea: Focus on plastic pollution

Marine litter affects various habitats across the world. This review focuses on the Adriatic region, considering the presence of marine litter as well as microplastics (mPs) and macroplastics (MPs) in different environments (water, beach, seabed and biota). Data from 53 scientific papers were critically analysed, providing a snapshot of this type of contamination, and evidencing critical issues. The final part of the review provides considerations on spatial and temporal trends, comparing data with the available information provided by transport forecasting models. It emerges that the most investigated areas are those most subjected to the contribution of rivers, tourism or have the greatest relevance to nature conservation. Our analysis also reveals that, even though many international research projects have played a fundamental role in the creation of shared methods and protocols, currently available data are difficult to compare. Nevertheless, our results enhance knowledge of the state of the art in the research carried out so far, and on the situation regarding pollution due to the marine litter in the Adriatic Sea, as well as highlighting avenues for future investigation.

Microplastic's story

The problem of microplastic pollution is now the order of the day in front of everyone's eyes affecting the environment and the health of leaving creature. This work aims to retrace the history of microplastics in a critical way through a substantial bibliographic collection, defining the points still unresolved and those that can be resolved. Presence of marine litter in different environments is reviewed on a global scale, focusing in particular on micro and macro plastics definition, classification and characterization techniques.

Microplastics pollution along the Lebanese coast (Eastern Mediterranean Basin): Occurrence in surface water, sediments and biota samples

The Mediterranean Sea is the largest semi-enclosed sea and one of the worst affected regional seas with sub-basin scale heterogeneity in plastics concentration. Few studies on microplastics (MPs) pollution have been conducted in the Eastern part of the Mediterranean basin. This study aims to evaluate, for the first time, the MPs pollution of the Lebanese coast (Levantine Basin) as well as the most common polymers found, and to assess the potential role of coastal landfills in this pollution. Two important seafood species that are wholly consumed by the Lebanese community: the European anchovy, Engraulis encrasicolus, and the spiny oysters, Spondylus spinosus, were sampled in three different sites englobing the littoral (Tripoli, Beirut and Sidon). Sea water and sediment samples were also collected from the same sites. Results showed different patterns of MPs concentration in the analyzed matrices: Sidon water sample was highly contaminated in MPs (6.7 MPs/m³) while Tripoli had the highest MPs in sediments (4.68 MPs/g). The occurrence of MPs in the biota was high (83.4% and 86.3% in anchovies and spiny oysters, respectively). Both anchovies and oysters from Beirut region had the highest ingested MPs/individual (2.9 ± 1.9 and 8.3 ± 4.4 MPs/individual, respectively). This study is the first that investigated microplastics ingestion by Spondylus spinosus while indicating the most common polymers found in the three matrices (water, sediments and biota) in the Eastern Mediterranean. These results highlighted the high MPs pollution found in the Levantine Basin in comparison to other Western Mediterranean regions. In addition, the obtained results indicate a potential contribution of coastal landfills to this pollution.

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.