The distribution and morphology of microplastics in coastal soils adjacent to the Bohai Sea and the Yellow Sea

Microplastics (<5 mm) are considered to be emerging pollutants of global concern. Investigations on microplastics pollution in coastal and marine environments have increased recently but knowledge gaps still exist regarding microplastics in coastal beach soils with high-intensity human activities. In the present study a total of 120 soil samples were taken from 53 sites along >3000 km of coastline in Shandong province, east China, adjacent to both the Bohai Sea and the Yellow Sea coastlines under different land use management. Microplastics were separated from the soil samples using a continuous flow and floating separation apparatus. The shape type, size, abundance, spatial distribution, polymer composition and surface morphology of the microplastics were identified by a range of advanced microscopic and micro-analytical methods. The analytical results show that seven shape types, namely foams, pellets, fragments, flakes, fibers, films and sponges, were present in the beach soils. The polymer composition of the microplastics included polyethylene, polypropylene, polystyrene, polyether urethane and a polymer blend of both polyethylene and polypropylene. Approximately 60% of the observed microplastics had a size range < 1 mm. Microplastic abundance varied greatly among the soils, ranging from 1.3 to 14,712.5 N kg−1 (dry weight) as influenced by high-intensity human activities such as mariculture, tourism, and port construction. The seven shape types of microplastics from the coastal environment had different weathering surface morphologies, showing scratches, creases, micropores, cracks, either concave or convex, and of various shapes and sizes, possibly due to physical friction, photochemical oxidation and/or animal attack. Algae or crude oil was observed on the surface of some microplastics. The weathered surfaces of microplastics might act as a high-capacity carrier with adhering microorganisms and chemicals. Further studies are required on the weathering processes, sorption capacity and transport of microplastics especially in smaller size (<1 mm) under coastal conditions.

Qian Zhou, Haibo Zhang, Chuancheng Fu and al., Geoderma, Volume 322, 15 July 2018, Pages 201–208

The article


Comparisons of microplastic pollution between mudflats and sandy beaches in Hong Kong

Most of the previous studies of microplastic pollution on coastal habitats focused on high energy beaches although low energy areas such as mudflats are supposed to retain more microplastics, not to mention that mudflats are biologically more diverse. We quantified and characterized microplastics from 10 mudflats and 10 sandy beaches in Hong Kong spanning from the eastern to western waters. Sediment samples were collected at 1.0 m and 1.5 m above chart datum (CD) and at the strandline. Abundance of microplastics ranged between 0.58 and 2116 items kg−1 sediment with that on mudflats being ten times more than on beaches. Polyethylene (46.9%) was the most abundant and followed by polypropylene (13.8%) and polyethylene terephthalate (13.5%). Expanded polystyrene was the most abundant in the strandline samples but not at 1.0 m and 1.5 m above CD. Although previous studies have concluded that the input from Pearl River is a major source of microplastics on Hong Kong shores, this study has demonstrated that the contribution of local pollution sources such as discharge from sewage treatment plants to microplastic pollution should not be neglected.

Hoi-Shing Lo, Xiaoyu Xu, Chun-Yuen Wong, Siu-Gin Cheung, Environmental Pollution, Volume 236, May 2018, Pages 208–217

The article

Dynamics of plastic resin pellets deposition on a microtidal sandy beach: Informative variables and potential integration into sandy beach studies


• Temporal dynamics of plastic resin pellets deposition ashore were investigated.
• Time-related categories depending on weathering of pellets were established.
• It was found a continuous input of pellets, of which about 50% recently released.
• Reduced beach width hosted higher pellets density independently of temporal variables.
• These findings can be integrated in both beach ecology and citizen science.

Lucia Fanini, Fabio Bozzeda, Ecological Indicators, Volume 89, June 2018, Pages 309–316

The article

Consistent patterns of debris on South African beaches indicate that industrial pellets and other mesoplastic items mostly derive from local sources

Identifying the sources of small plastic fragments is challenging because the original source item seldom can be identified. South Africa provides a useful model system to understand the factors influencing the distribution of beach litter because it has an open coastline with four equally-spaced urban-industrial centres distant from other major source areas. We sampled mesodebris (∼2–25 mm) at 82 South African beaches in 1994, 2005 and 2015. Plastic items comprised 99% by number and 95% by mass of litter items. Industrial pellets were the most abundant plastic items, but fragments of rigid plastic items comprised most of the mass of debris. Strong correlations between industrial pellets and other plastic items indicate that common factors influence the distribution of both pellets and secondary mesoplastics. The abundance of mesodebris at beaches also was correlated in successive surveys, suggesting that beach-specific factors (e.g. aspect, slope, local currents, etc.) influence the amounts of debris on each beach. Sample year had no effect on mesodebris abundance, indicating that there has been little change in the amounts of mesodebris over the last two decades. There were consistently higher densities of both industrial pellets and other plastic items at beaches close to urban-industrial centres; there were only weak correlations with human population density and no correlation with local runoff. The size of industrial pellets decreased away from local urban centres, further supporting the conclusion that, like macroplastic litter, most mesoplastic pollution on continental beaches derives from local, land-based sources. This finding means that local actions to reduce plastics entering the sea will have local benefits, and that it may be possible to assess the efficacy of mitigation measures to reduce marine inputs of mesoplastic items.

Peter G. Ryan, Vonica Perold, Alexis Osborne, Coleen L. Moloney, Environmental Pollution, Available online 16 February 2018, In Press

The article

Three-dimensional distribution of anthropogenic microparticles in the body of sandy beaches

External oceanographic conditions rather than anthropogenic influence are shown to cause the 3-dimensional distribution of anthropogenic microparticles (MP, 0.5–5 mm) within the body of sandy beaches of a non-tidal sea with strong wind/wave climate and seasonal sea level variations (the Baltic Sea). A patchy structure is confirmed in all three dimensions, with background concentrations of several tens of MP items per kg of dry sample weight versus peaking spots with several hundreds of items per kg dry weight. The background MP concentrations are of the same order of magnitude for the beach surface, beach body, and sands of underwater coastal slopes, highlighting that the contaminated by MPs sand cover of the entire sea coastal zone is one single entity, repeatedly re-distributed between its underwater and beach parts by every next storm. Peaking concentrations are related to stormy events and places with stronger water dynamics, and are associated with locations of coarser sands within the beach body and wracklines at the beach surface. This suggests that marine waters are the source of anthropogenic microparticles for the beach, and not vice versa. The prevalence of wave-driven over wind-driven beaching mechanism for MPs extracted from the beach samples is confirmed by the flotation tests. Size distribution of the extracted MPs is found to be similar to that obtained for plastics floating at the ocean surface. Such a coherency for different oceanic environments speaks in favor of independence of general fragmentation processes on the particular external conditions, shifting the attention to the fragmentation process and material properties of synthetic particles in marine environment.

I.P. Chubarenko, E.E. Esiukova, A.V. Bagaev and al., Science of The Total Environment, Volumes 628–629, 1 July 2018, Pages 1340–1351

The article

Beach litter along various sand dune habitats in the southern Adriatic (E Mediterranean)

Marine litter accumulates on sandy beaches and is an important environmental problem, as well as a threat to habitat types that are among the most endangered according to EU legislation. We sampled 120 random plots (2 × 2 m) in spring 2017 to determine the distribution pattern of beach litter along the zonation of habitat types from sea to the inland.

The most frequent litter items were plastic, polystyrene and glass. A clear increase of litter cover along the sea-inland gradient is evident, and foredunes and pine forests have the highest cover of litter. Almost no litter was present in humid dune slacks. Shoreline and recreational activities are the major source of beach litter, while ocean/waterway activities are more important in the aphytic zone and strandline.

Urban Šilc, Filip Küzmič, Danka Caković, Danijela Stešević, Marine Pollution Bulletin, Volume 128, March 2018, Pages 353–360

The article

Alert calling in port areas: Marine litter as possible secondary dispersal vector for hitchhiking invasive species

Floating plastic debris, such as bottles and fishing gear, is a shelter for different species in the oceans. Litter may therefore help the spread of non-indigenous species (NIS). Here we have challenged the idea of using the abundance of marine litter present in a zone to estimate the risk of NIS introduction. To test this, a targeted sampling of plastic bottles and fishing gear (ropes and nets) was performed along 22 beaches from the Cantabrian coast where ports have been reported as a source of biological invasions. All items with attached organisms were collected and recorded. Genetic barcoding was used to ascertain the species and identify NIS. In total 17 species attached to plastic bottles and fishing gears were identified. Three of them, found on the two types of items, are catalogued as invasive species: Austrominius modestus; Magallana gigas; and, Amphibalanus amphitrite. Prevalence and mean intensity of non-indigenous biota on plastic bottles and fishing gear were not significantly different. The abundance of barnacles in litter was significantly correlated with that found from ports in the same region. The results suggest that ropes are able to transport different marine organisms and NIS as plastic bottles do. Monitoring biota on marine litter could serve as an additional tool for NIS detection.

Laura Miralles, Marta Gomez-Agenjo, Fernando Rayon-Viña and al., Journal for Nature Conservation, Volume 42, April 2018, Pages 12–18

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