Transboundary movement of marine litter in an estuarine gradient: Evaluating sources and sinks using hydrodynamic modelling and ground truthing estimates

Marine debris’ transboundary nature and new strategies to identify sources and sinks in coastal areas were investigated along the Paranaguá estuarine gradient (southern Brazil), through integration of hydrodynamic modelling, ground truthing estimates and regressive vector analysis. The simulated release of virtual particles in different parts of the inner estuary suggests a residence time shorter than 5 days before being exported through the estuary mouth (intermediate compartment) to the open ocean. Stranded litter supported this pathway, with beaches in the internal compartment presenting proportionally more items from domestic sources, while fragmented items with unknown sources were proportionally more abundant in the oceanic beaches. Regressive vector analysis reinforced the inner estuarine origin of the stranded litter in both estuarine and oceanic beaches. These results support the applicability of simple hydrodynamic models to address marine debris’ transboundary issues in the land-sea transition zone, thus supporting an ecosystem transboundary (and not territorial) management approach.

Allan Paul Krelling, Mihael Machado Souza, Allan Thomas Williams, Alexander Turra, Marine Pollution Bulletin, Volume 119, Issue 1, 15 June 2017, Pages 48–63

The article

Colour spectrum and resin-type determine the concentration and composition of Polycyclic Aromatic Hydrocarbons (PAHs) in plastic pellets

This study assessed the concentration and composition of Polycyclic Aromatic Hydrocarbons (PAHs) in plastic pellets, collected from sandy beaches and considered different resin and colour tones. Results showed that polyethylene pellets, while displaying a greater range of total PAH concentrations did not differ significantly from polypropylene pellets. More importantly, both resin types demonstrated predictable increases in total PAH across a spectrum of darkening colour tones. Multivariate comparisons of 36 PAH groups, further showed considerable variability across resin type and colour, with lighter coloured pellets comprising lower molecular weight, while darker pellets contained higher weight PAHs. Overall, we show predictable variation in PAH concentrations and compositions of plastic pellets of different ages and resin types that will directly influence the potential for toxicological effects. Our findings suggest that monitoring programs should take these attributes into account when assessing the environmental risks of microplastic contamination of marine and coastal habitats.

Mara Fisner, Alessandra Majer, Satie Taniguchi, Márcia Bícego, Alexander Turra, Daniel Gorman, Marine Pollution Bulletin, Available online 3 July 2017, In Press

The article

Quantifying Microplastics on National Park Beaches

This report details the results from a project funded by the NOAA Marine Debris Program and led by the National Park Service (link is external) and Clemson University (link is external), in which beach sediments were collected and analyzed to assess the abundance and distribution of microplastics and microfibers on U.S. National Park beaches. Thirty-seven National Park beaches, representing 35 National Parks, Monuments, Seashores, and Recreation areas were sampled for microplastics and microfibers. Scientists found microplastics or microfibers in sand samples collected from all 37 beaches. Microfibers were the predominant type of debris found (97% by count). Individual beaches in the Great Lakes and Pacific Islands had the highest concentrations of microplastics and microfibers. Microplastics and microfibers were even found in remote areas of Alaska. (NOAA, June 2017)

The report

Beach macro-litter monitoring and floating microplastic in a coastal area of Indonesia

Qualitative analysis of the structures of the polymers composing floating plastic debris was performed using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and the aging of the debris was assessed by measuring carbonyl group formation on the particle surfaces. Plastic material made up > 75% of the 2313 items collected during a three-year survey. The size, shape and color of the microplastic were correlated with the polymer structure. The most abundant plastic materials were polypropylene (68%) and low-density polyethylene (11%), and the predominant colors of the plastics were white, blue and green. Cilacap Bay, Indonesia, was contaminated with microplastic at a concentration of 2.5 mg·m3. The carbonyl index demonstrated that most of the floating microplastic was only slightly degraded. This study highlights the need to raise environmental awareness through citizen science education and adopting good environmental practices.

Agung Dhamar Syakti, Rafika Bouhroum, Nuning Vita Hidayati and al., Marine Pollution Bulletin, Available online 20 June 2017, In Press

The article

OSPAR standard method and software for statistical analysis of beach litter data

The aim of this study is to develop standard statistical methods and software for the analysis of beach litter data. The optimal ensemble of statistical methods comprises the Mann-Kendall trend test, the Theil-Sen slope estimation, the Wilcoxon step trend test and basic descriptive statistics. The application of Litter Analyst, a tailor-made software for analysing the results of beach litter surveys, to OSPAR beach litter data from seven beaches bordering on the south-eastern North Sea, revealed 23 significant trends in the abundances of beach litter types for the period 2009–2014. Litter Analyst revealed a large variation in the abundance of litter types between beaches. To reduce the effects of spatial variation, trend analysis of beach litter data can most effectively be performed at the beach or national level. Spatial aggregation of beach litter data within a region is possible, but resulted in a considerable reduction in the number of significant trends.

Marcus Schulz, Willem van Loon, David M. Fleet, Paul Baggelaar, Eit van der Meulen, Marine Pollution Bulletin, Available online 21 June 2017, In Press

The article

An estimation of the average residence times and onshore-offshore diffusivities of beached microplastics based on the population decay of tagged meso- and macrolitter

Residence times of microplastics were estimated based on the dependence of meso- and macrolitter residence times on their upward terminal velocities (UTVs) in the ocean obtained by one- and two-year mark-recapture experiments conducted on Wadahama Beach, Nii-jima Island, Japan. A significant linear relationship between the residence time and UTV was found in the velocity range of about 0.3–0.9 ms− 1, while there was no significant difference between the residence times obtained in the velocity range of about 0.9–1.4 ms− 1. This dependence on the UTV would reflect the uprush-backwash response of the target items to swash waves on the beach. By extrapolating the linear relationship down to the velocity range of microplastics, the residence times of microplastics and the 1D onshore-offshore diffusion coefficients were inferred, and are one to two orders of magnitude greater than the coefficients of the macroplastics.

Hirofumi Hinata, Keita Mori, Kazuki Ohno, Yasuyuki Miyao, Tomoya Kataoka, Marine Pollution Bulletin, Available online 16 June 2017, In Press

The article