Microplastic pollution on Caribbean beaches in the Lesser Antilles

Here we investigate microplastics contamination on beaches of four islands of the Lesser Antilles (Anguilla, St. Barthélemy, St. Eustatius and St. Martin/Maarten). These islands are close to the North Atlantic subtropical gyre, which contains high levels of microplastics. On average 261 ± 6 microplastics/kg of dry sand were found, with a maximum of 620 ± 96 microplastics on Grandes Cayes, Saint Martin. The vast majority of these microplastics (>95%) were fibers. Levels of microplastics differed among islands, with significantly lower levels found in St. Eustatius compared to the other Islands. No difference in microplastic levels was found between windward and leeward beaches. Our research provides a detailed study on microplastics on beaches in the Lesser Antilles. These results are important in developing a deeper understanding of the extent of the microplastic challenge within the Caribbean region, a hotspot of biodiversity.

Thijs Bosker, Lucia Guaita, Paul Behrens, Marine Pollution Bulletin, Volume 133, August 2018, Pages 442–447

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Microplastics on the Portuguese coast

Marine anthropogenic litter was analysed in eleven beaches along the Portuguese coast, over a two-year period (2011−2013). Of all collected items, 99% were plastic and 68% were microplastics (MP; 1–5 mm in diameter). Higher MP concentrations were found in winter/autumn, near industrial areas and/or port facilities and in beaches exposed to dominant winds. Resin pellets (79%) were the dominant category close to industrial areas and high concentrations of fragments and polymeric foams were found near fishing ports. The most frequent pellet size classes were 4 and 5 mm (respectively 47% and 42%). Results suggest that MP have predominately a land-based origin and are deliberately discarded or accidentally lost in watercourses and/or coastal areas. A combination of measures within stakeholders, namely industry and fishing sectors and share of good practices are needed to prevent marine anthropogenic litter.

J. Antunes, J. Frias, P. Sobral, Marine Pollution Bulletin, Volume 131, Part A, June 2018, Pages 294-302

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Sticky tape and simulations help assess microplastic risk

Tiny pieces of plastic, now ubiquitous in the marine environment, have long been a cause of concern for their ability to absorb toxic substances and potentially penetrate the food chain. Now scientists are beginning to understand the level of threat posed to life, by gauging the extent of marine accumulation and tracking the movement of these contaminants. (…)

N. Grover, Horizon EU magazine, 23/04/2018

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Optimising beached litter monitoring protocols through aerial imagery

The monitoring of beached litter along the coast is an onerous obligation enshrined within a number of legislative frameworks (e.g. the MSFD) and which requires substantial human resources in the field. Through this study, we have optimised the protocol for the monitoring of the same litter along coastal stretches within an MPA in the Maltese Islands through aerial drones, with the aim of generating density maps for the beached litter, of assisting in the identification of the same litter and of mainstreaming this type of methodology within national and regional monitoring programmes for marine litter. Concurrent and concomitant in situ monitoring of beached litter enabled us to ground truth the aerial imagery results. Results were finally discussed within the context of current and future MSFD monitoring obligations, with considerations made on possible future policy implications.

A. Deidun, A. Gauci, S. Lagorio, F. Galgani, Marine Pollution Bulletin, Volume 131, Part A, June 2018, Pages 212–217

The article

Abundance, composition, and distribution of microplastics larger than 20 μm in sand beaches of South Korea

To support microplastic management, the abundance, composition, and spatial distribution of microplastics on a national scale must be known. Hence, we studied the baseline level of microplastic pollution at 20 sandy beaches along the South Korean coast. All microplastic particles extracted from the sand samples were identified down to 20 μm in size using Fourier transform infrared spectroscopy. The abundances of large microplastics (L-MPs; 1–5 mm) and small microplastics (S-MPs; 0.02–1 mm) were in the range of 0–2088 n/m2 and 1400–62800 n/m2, respectively. Maximum microplastic abundance was in the size range of 100–150 μm, and particles smaller than 300 μm accounted for 81% of the total abundance. Expanded polystyrene (EPS) accounted for 95% of L-MPs, whereas S-MPs were predominantly composed of polyethylene (49%) and polypropylene (38%). The spatial distribution of L-MPs, excluding EPS, was significantly related to population, precipitation, proximity to a river mouth and abundance of macroplastic debris on beach. However, there were no relationships between S-MPs and other environmental and source-related factors, except for macroplastic debris and L-MPs excluding EPS. These results imply that S-MPs are mainly produced on beaches by weathering, whereas L-MPs other than EPS are mainly introduced from land-based sources and are also partly produced on beaches.

Soeun Eo, Sang Hee Hong, Young Kyoung Song and al., Environmental Pollution, Volume 238, July 2018, Pages 894-902

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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

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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

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