The occurrence of microplastic contamination in littoral sediments of the Persian Gulf, Iran

Microplastics (MPs; <5 mm) in aquatic environments are an emerging contaminant of concern due to their possible ecological and biological consequences. This study addresses that MP quantification and morphology to assess the abundance, distribution, and polymer types in littoral surface sediments of the Persian Gulf were performed. A two-step method, with precautions taken to avoid possible airborne contamination, was applied to extract MPs from sediments collected at five sites during low tide. MPs were found in 80% of the samples. Across all sites, fiber particles were the most dominate shape (88%), followed by films (11.2%) and fragments (0.8%). There were significant differences in MP particle concentration between sampling sites (p value <0.05). The sediments with the highest numbers of MPs were from sites in the vicinity of highly populated centers and municipal effluent discharges. FTIR analysis showed that polyethylene (PE), nylon, and polyethylene terephthalate (PET) were the most abundant polymer types. More than half of the observed MPs (56%) were in the size category of 1–4.7 mm length, with the remaining particles (44%) being in the size range of 10 μm to <1 mm. Compared to literature data from other regions, intertidal sediments in the Persian Gulf cannot be characterized as a hot spot for MP pollution. The present study could, however, provide useful background information for further investigations and management policies to understand the sources, transport, and potential effects on marine life in the Persian Gulf.

Abolfazl Naji, Zinat Esmaili, Sherri A. Mason, A. Dick Vethaak, Environmental Science and Pollution Research, pp 1–10, 14 July 2017

The article

Microplastic contamination of intertidal sediments of Scapa Flow, Orkney: A first assessment

The concentration of microplastic particles and fibres was determined in the intertidal sediments at selected sites in Scapa Flow, Orkney, using a super-saturated NaCl flotation technique to extract the plastic and FT-IR spectroscopy to determine the polymer types. Mean concentrations were 730 and 2300 kg− 1 sediment (DW), respectively. Detailed spatial and quantitative analysis revealed that their distribution was a function of proximity to populated areas and associated wastewater effluent, industrial installations, degree of shore exposure and complex tidal flow patterns. Sediment samples from Orkney showed similar levels of microplastic contamination as in two highly populate industrialized mainland UK areas, The Clyde and the Firth of Forth. It was concluded that relative remoteness and a comparative small island population are not predictors of lower microplastic pollution. Furthermore, a larger concerted effort across Scotland and the UK is required to establish a baseline microplastic database for the evaluation of future policy measures.

J. Blumenröder, P. Sechet, J.E. Kakkonen, M.G.J. Hartl, Marine Pollution Bulletin, Available online 11 July 2017, In Press

The article

The first evaluation of microplastics in sediments from the complex lagoon-channel of Bizerte (Northern Tunisia)

Microplastics (MPs) in sediments from the complex lagoon-channel of Bizerte were investigated, for the first time, to evaluate the occurrence and abundance of MPs in Tunisia. After density separation in saline solution, MPs were counted by a stereomicroscope. The number of MPs was at the range of 3–18 items/g sediment (3000–18,000 items/kg dry sediment) and the most contaminated site was of Menzel Abderrahmane (MA) followed by Carrier Bay (CB), Menzel Jemil (MJ) and Channel of Bizerte (C). The MPs gathered during the survey varied in size from 0.3 to 5 mm, and appear in a variety of shapes and colours. The dominant shape was fibre (88.88% in MA, 91.00% in CB, 82.35% in C and 21.05% in MJ). The rest of MPs are fragments whilst no micro beads were found. Colours are clear, white, blue, green, red and black. Cities discharges, fishing activity and industrial production sites are the most likely sources of MPs. This first work provides original data on the presence of MPs that determines their bioavailability to organisms as seafood, and then possibly transfers of to human. The high MP concentrations registered in the complex lagoon-channel of Bizerte suggest that this site is a hotspot for MP pollution and there is an urgency to understand their origins and effects on marine life. The results will provide useful background information for further investigations.

Sami Abidli, Hela Toumi, Youssef Lahbib, Najoua Trigui El Menif, Water, Air, & Soil Pollution,  July 2017, 228:262

The article

Screening for microplastics in sediment, water, marine invertebrates and fish: Method development and microplastic accumulation

Measurements of microplastics in biota and abiotic matrices are key elements of exposure and risk assessments for this emerging environmental pollutant. We investigated the abundance of microplastics in field-collected biota, sediment and water. An improved sediment extraction method, based on density separation was developed. For analysis of microplastics in biota we found that an adapted enzymatic digestion protocol using proteinase K performed best, with a 97% recovery of spiked plastic particles and no observed degradation effects on the plastics in subsequent Raman analysis. Field analysis revealed that 8 of 9 tested invertebrate species from the North Sea and 68% of analyzed individuals of brown trout (Salmo trutta) from the Swedish West Coast had microplastics in them. Based on the number of plastic particles per kg d.w. the microplastic concentrations found in mussels were approximately a thousand-fold higher compared to those in sediment and surface water samples from the same location.

Therese M. Karlsson, A. Dick Vethaak, Bethanie Carney Almroth, Freek Ariese, Martin van Velzen, Martin Hassellöv, Heather A. Leslie, Marine Pollution Bulletin, Available online 6 July 2017, In Press

The article

The effect of microplastic on the uptake of chemicals by the lugworm Arenicola marina (L.) under environmentally relevant exposure conditions

It has been hypothesized that ingestion of microplastic increases exposure of aquatic organisms to hydrophobic contaminants. To date, most laboratory studies investigated chemical transfer from ingested microplastic without taking other exposure pathways into account. Therefore we studied the effect of polyethylene (PE) microplastic in sediment on PCB uptake by Arenicola marina as a model species, quantifying uptake fluxes from all natural exposure pathways. PCB concentrations in sediment, biota lipids (Clip) and porewater measured with passive samplers were used to derive lipid-normalized bioaccumulation metrics Clip, Biota sediment accumulation factor (BSAF), Bioaccumulation factor (BAF) and the Biota plastic accumulation factor (BPAF). Small effects of PE addition were detected suggesting slightly increased or decreased bioaccumulation. However, the differences decreased in magnitude dependent on the metric used to assess bioaccumulation, in the order: Clip>BSAF>BPAF>BAF, and were non-significant for BAF. The fact that BAF, i.e. normalization of Clip on porewater concentration, largely removed all effects of PE, shows that PE did not act as a measurable vector of PCBs. Biodynamic model analysis confirmed that PE ingestion contributed marginally to bioaccumulation. This work confirmed model-based predictions on the limited relevance of microplastic for bioaccumulation under environmentally realistic conditions, and illustrated the importance of assessing exposure through all media in microplastic bioaccumulation studies.

Ellen Besseling, Edwin M. Foekema, Martine J. Van Den Heuvel-Greve, and Albert A. Koelmans, Environ. Sci. Technol., Just Accepted Manuscript, July, 6, 2017

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

Microplastics in the sediments of Terra Nova Bay (Ross Sea, Antarctica)

This is the first survey to investigate the occurrence and extent of plastic contamination in sediments collected in Terra Nova Bay (Ross Sea, Antarctica). Plastic debris extracted from 31 samples of sediments were counted, weighted and identified by Fourier-transform infrared spectroscopy (FT-IR). All sediment samples contained plastics: a total of 1661 items of debris (3.14 g) were recorded from the 31 samples of sediment. Plastic particles in the samples ranged from 0.3 to 22 mm in length. Fibres were the most frequent type of small plastics debris detected. In terms of abundance, microplastics (< 5 mm) accounted for 78.4% of debris. 9 polymer types were found: the most common material (94.13% by weight) was styrene-butadiene-styrene copolymer (SBS), widely used in pneumatic tires, etc. A decreasing concentration of plastic debris at increasing distances from the Mario Zucchelli Base was evidenced.

Cristina Munari, Vanessa Infantini, Marco Scoponi, Eugenio Rastelli, Cinzia Corinaldesi, Michele Mistri, Marine Pollution Bulletin, Available online 20 June 2017, In Press

The article