Abundance and mass of plastic litter on sandy shore: Contribution of stormy events.

The accumulation of marine litter on beaches has a detrimental impact on the environment, human health, and recreational activities. A total of 116 monitoring surveys were conducted along the shore of the Kaliningrad region between 2019 and 2023. Sampling of anthropogenic and plastic litter (>0.5 cm) was carried out under various meteorological conditions on eight sandy beaches. The greatest abundance and mass of plastic marine litter (mean ± SE: 13.75 ± 8.61 items/m2 and 19.97 ± 5.92 gDW/m2, correspondingly) were observed in the aftermath of storms within beach-cast accumulation stains at the shoreline, where it was intermixed with organic debris. This is two orders of magnitude greater than the plastic litter contamination obtained using the OSPAR methodology at the same beach during fine weather (0.11 ± 0.01 items/m2, 0.33 ± 0.02 gDW/m2). The results suggest that the most effective strategy for beach cleaning is to implement it in the post-storm period.

Natural sorting of sediments in the wave run-up zone works for microplastics as well.

The distribution of plastic pollution in the marine environment is highly variable in time and space, making it difficult to assess pollution levels. This study shows that mixing and natural sorting of material in the wave run-up zone of a sandy beach results in a relatively stable abundance of microplastics in the size range 0.5-2 mm (S-MPs). Based on 175 samples collected over 14 months during 42 monitoring surveys at 6 stations along the shore of the Vistula Spit (Baltic Sea), the mean abundance of S-MPs was found to be 64 ± 36 items/kg DW (98.6 % fibers), with a coefficient of variation of only 56 % over more than one year. Statistical tests confirmed its independence from current wind speed, significant wave height, mean sediment grain size, sediment sorting, percentage of certain sand fractions, month, season, or location along the shore. It can therefore be used as a suitable indicator for long-term monitoring of increasing plastic pollution in the marine environment.

The interactions of plastic with tar and other petroleum derivatives in the marine environment: A general perspective.

Plastic and oil pollution are closely linked to our dependence on petroleum derivatives. Their excessive use and inefficiencies in their management, have led to negative impacts on marine ecosystems since their very introduction. Agglomerates of tar, plastic, paraffins, and other petrochemicals and oil derivatives with naturally occurring materials, are increasingly widespread in coastal environments, stalling as an iconic and readable sign of environmental degradation. Starting from a historical review of the available reports on the occurrence of similar aggregates dating back to 1971, we highlight how most of these observations are based on the morphological description of the petroleum residues with no chemical fingerprinting and are mainly related to materials stranded on the coastline, with few and unclear indications for the open sea. We discuss here a list of scientific questions and knowledge gaps, that need to be examined by future studies.

Microplastics in sea ice: A fingerprint of bubble flotation.

Sea ice is heavily contaminated with microplastics (MPs), with the repeatedly confirmed increased number of larger-sized particles, deficit of fibers, and prevalence of materials denser than the surrounding water. To get insight into the drivers behind such a specific pattern, sets of laboratory experiments were performed on the formation of ice by cooling from the surface of fresh and salty (NaCl, 34 g/L) water, with particles of different sizes from heavy plastics (HPP) distributed initially over the bottom of the experimental volume. After freezing, about 50-60 % of HPP were trapped in ice in all the runs. Vertical distribution of HPP, plastic mass distribution, ice salinity (in saltwater experiments), and bubble concentration (in freshwater experiments) were recorded. Formation of bubbles on hydrophobic surfaces was the main cause of the entrapment of HPP into ice, with convection playing a secondary role. Supplementary bubble formation experiments with the same particles in water demonstrated that at larger fragments and fibers, several bubbles grow at the same time, so particle rising and residing at the surface is stable. Smaller HPP experience rising/sinking cycles with minimum time spent at the surface: one bubble is enough to cause a particle rising, but it is most often lost when colliding with the water surface. Application of the results to oceanic conditions is discussed. Oversaturation with gases due to various physical/biological/chemical processes and liberation of bubbles from methane seeps and melting permafrost are common in Arctic waters. Convective water motions are able to relocate HPP in vertical. Based on applied research, the bubble nucleation and growth, the hydrophobicity of weathered surfaces, the effectiveness of flotation methods for plastic particles are discussed. Interaction of plastic particles with bubbles is an important feature, still completely overlooked in the context of MPs behavior in marine environment.

Microplastics distribution in bottom sediments of the Baltic Sea Proper.

An abundance of microplastics particles (0.2-5 mm, MPs) in bottom sediments is analyzed based on 53 samples (3 to 215 m deep) obtained in 8 cruises of research vessels across the Baltic Sea Proper in March-October 2015-2016. MPs content varied between stations from 103 up to 10,179 items kg-1 d.w., with the bulk mean of 863 ± 1371 items kg-1 d.w., showing a statistically significant increase with water depth. As many as 74.5% of MPs are of fibrous shape, followed by films (19.8%) and fragments (5.7%). The distributions of fibres, fragments, films, and different types of natural bottom sediments are significantly different, highlighting the specific behaviour of each of these kinds of bottom deposits. A statistically significant correlation between water depth and fibres content is found. Based on the analysis of oceanographic factors and sedimentological principles, an erosion/transition/accumulation pattern for fibres in the Baltic Sea Proper is outlined. Fibres can be considered as a specific type of "synthetic sediment", while principles of distribution of other MPs are not yet certain.

Dataset on geosynthetic material debris contamination of the South-East Baltic shore.

The database gives information on the contamination of the shore of the South-Eastern Baltic with the debris of geosynthetic materials for the period 2018-2020. This new type of coastal pollution enters the natural environment due to the destruction of coastal protection structures and construction activities. The database contains sections: (1) a list of types of geosynthetic material residues, their photographic images and photographs illustrating examples of finds in natural conditions [1 List_geosynthetic_debris_SEB], (2) monitoring data on the contamination of the beach strip with the debris of geotextiles, braids from gabions, geocontainers (big bags), geocells and geogrids for the beaches of the South-Eastern Baltic for the period 2018-2020 [2 Monitoring_geosynthetic_debris_SEB]; (3) statistical distributions of the found geosynthetic debris by size [3 Scales_geosynthetic_debris_SEB] and (4) results of test surveys on the shores of Lithuania and Poland adjacent to Kaliningrad Oblast. All data refer to the beaches of the Kaliningrad Oblast (Russia), including the Russian parts of the Vistula and Curonian Spits, but also contains information on a one-time assessment of the pollution of the beaches of the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Materials were collected during field surveys within the ERANET-RUS_Plus joint project EI-GEO, ID 212 (RFBR 18-55-76002 ERA_a, BMBF 01DJ18005).

Investigations of plastic contamination of seawater, marine and coastal sediments in the Russian seas: a review.

Twelve seas with an integral coastline length of about 38,000 km wash upon the Russian coasts. They belong to the basins of the Atlantic, the Arctic, and the Pacific Oceans and stretch over temperate, subpolar, and polar climate zones. This review of 32 studies published between 2015 and August 2020 analyses the available peer-reviewed scientific publications related to the topic of plastic contamination. At present, plastic contamination of the marine environments is confirmed by field investigations in 7 out of 12 Russian seas. Pollution levels vary widely: from 0.6 to 336,000 items/m3 for microplastics in water and from 1.3 to 10,179 items/kg (DW)-in sediments, while median macroplastics abundance is around 1.0 item/m2 at the coast. One monitoring survey of the Barents Sea reported mean macroplastics concentration in the upper 60 m as 0.011 mg/m3 and 2.9 kg/km2 at the sea floor. The identification of the polymer types with spectroscopy techniques is performed only in 9 studies (28%); most researchers use visual identification which makes the results difficult to compare. Most projects aimed at the plastic contamination research use their own collection and extraction methods that poorly agree with other studies. Since the pollution levels in most of the areas are relatively low, sampling is inhomogeneous in space and time. The most extensively studied areas are the beaches of the Baltic Sea, while the least examined is the Arctic region. Our study highlights the need for a discussion on harmonizing sampling methodology and identification techniques among different studies.

Environmental Impact of Geosynthetics in Coastal Protection.

Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80 °C and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years. Dynamic surface leaching and ecotoxicological tests were performed to determine the possible release of contaminants. No harmful effects on the test organisms were observed.

Data on microplastic contamination of the Baltic Sea bottom sediment samples in 2015-2016.

The contamination by microplastics particles (MPs, 0.2-5 mm) in bottom sediments of the Baltic Sea is quantified. In total, 53 sediment samples were obtained in 8 cruises of research vessels in July-October 2015 and March-December 2016. The depths from 3 to 215 m in the Gotland, Gdansk, and Bornholm Basins are covered. Primary data is provided, along with exhaustive information on sampling dates and coordinates, depths, sampling methods, extracting procedures, control measures, detection techniques, and verification by µ-Raman spectroscopy. Number of pieces per kg dry weight is determined separately for fibres, films, and fragments. Distributions by size, plastic colour, and plastic type are presented. Modified NOAA method and µ-Raman spectroscopy were applied to obtain the data, thus they can be used for comparative analyses.

From macro to micro: dataset on plastic contamination along and across a sandy tide-less coast (the Curonian Spit, the Baltic Sea).

The contamination by macrolitter (>25 mm), mesolitter (5-25 mm), large microlitter (2-5 mm), large and small microplastics (L-MPs (2-5 mm) and S-MPs (0.5-2 mm), accordingly) in the surface beach sand at 6 locations along the 100-km-long marine coast of the Curonian Spit UNESCO National Park and the neighboring city beaches is quantified. In total, 55 samples obtained during 1-2 May 2018 are analyzed. Primary data is provided, along with exhaustive information on sampling dates and coordinates, sampling methods, extracting procedures, control measures, detection techniques, and µ-Raman spectroscopy verification. The number of items per m2 and items per kg dry weight (for MPs) is determined separately for fibres, films, and fragments. Distributions by size and plastic type are presented. Standard protocols, a modified NOAA method, and µ-Raman spectroscopy were applied to obtain the data, thus they can be used for comparative analyses.

Plastic pollution on the Baltic beaches of Kaliningrad region, Russia.

Contamination of sandy beaches of the Baltic Sea in Kaliningrad region is evaluated on the base of surveys carried out from June 2015 to January 2016. Quantity of macro/meso/microplastic objects in the upper 2cm of the sandy sediments of the wrack zone at 13 sampling sites all along the Russian coast is reported. Occurrence of paraffin and amber pieces at the same sites is pointed out. Special attention is paid to microplastics (range 0.5-5mm): its content ranges between 1.3 and 36.3 items per kg dry sediment. The prevailing found type is foamed plastic. No sound differences in contamination are discovered between beaches with high and low anthropogenic load. Mean level of contamination is of the same order of magnitude as has been reported by other authors for the Baltic Sea beaches.