Plastic found in mussels from Arctic to China – enters human food

Tiny bits of plastic are contaminating mussels from the European Arctic to China in a sign of the global spread of ocean pollution that can end up on people’s dinner plates.

Mussels in apparently pristine Arctic waters had most plastic of any tested along the Norwegian coast, according to a study this month by the Norwegian Institute for Water Research (NIVA).

Plastics may be getting swept north by ocean currents and winds from Europe and America, ending up swirling around the Arctic Ocean, NIVA researcher Amy Lusher told Reuters.

“Microplastics have been found in mussels everywhere scientists have looked,” she said.

Past surveys have found microplastics off nations including China, Chile, Canada, Britain and Belgium. Off Norway, the molluscs contained on average 1.8 bits of microplastic – defined as smaller than 5 mm long (0.2 inch) – with 4.3 in the Arctic. (…) (reuters.com, 20/12/2017)

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Assessing the relationship between the abundance and properties of microplastics in water and in mussels

Microplastic pollution is increasingly becoming a great environmental concern worldwide. Microplastics have been found in many marine organisms as a result of increasing plastic pollution within marine environments. However, the relationship between micoplastics in organisms and their living environment is still relatively poorly understood. In the present study, we investigated microplastic pollution in the water and the mussels (Mytilus edulis, Perna viridis) at 25 sites along the coastal waters of China. We also, for the first time, conducted an exposure experiment in parallel on the same site using M. edulis in the laboratory. A strong positive linear relationship was found between microplastic levels in the water and in the mussels. Fibers were the dominant microplastics. The sizes of microplastics in the mussels were smaller than those in the water. During exposure experiments, the abundance of microbeads was significantly higher than that of fibers, even though the nominal abundance of fibers was eight times that of microbeads. In general, our results supported positive and quantitative correlations of microplastics in mussels and in their surrounding waters and that mussels were more likely to ingest smaller microplastics. Laboratory exposure experiment is a good way to understand the relative impacts of microplastics ingested by marine organisms. However, significant differences in the results between exposure experiments and field investigations indicated that further efforts are needed to simulate the diverse environmentally relevant properties of microplastics.

Xiaoyun Qu, Lei Su, Hengxiang Li, Mingzhong Liang, Huahong Shi, Science of The Total Environment, Volume 621, 15 April 2018, Pages 679–686

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Factors influencing the microplastic contamination of bivalves from the French Atlantic coast: Location, season and/or mode of life?

Monitoring the presence of microplastics (MP) in marine organisms is currently of high importance. This paper presents the qualitative and quantitative MP contamination of two bivalves from the French Atlantic coasts: the blue mussel (Mytilus edulis) and the Pacific oyster (Crassostrea gigas). Three factors potentially influencing the contamination were investigated by collecting at different sampling sites and different seasons, organisms both wild and cultivated. Inter- and intra-species comparisons were also achieved. MP quantity in organisms was evaluated at 0.61 ± 0.56 and 2.1 ± 1.7 MP per individual respectively for mussels and oysters. Eight different polymers were identified. Most of the MPs were fragments; about a half of MPs were grey colored and a half with a size ranging from 50 to 100 μm for both studied species. Some inter-specific differences were found but no evidence for sampling site, season or mode of life effect was highlighted.

Nam Ngoc Phuong, Laurence Poirier, Quoc Tuan Pham, Fabienne Lagarde, atlAurore Zalouk-Vergnoux, Marine Pollution Bulletin, Available online 26 October 2017, In Press

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A simple method to quantify PC and PET microplastics in the environmental samples by LC-MS/MS

Occurrence of microplastics (MPs) in the environments have been frequently reported. However, studies on the quantification methods for MPs are still needed. Plastics are polymers of different degrees of polymerization. In this study, alkali assisted thermal hydrolysis was applied to depolymerize two plastics containing ester groups, polycarbonate (PC) and polyethylene terephthalate (PET), in pentanol or butanol system. By determining the concentrations of the depolymerized building block compounds, i.e. bisphenol A (BPA) and para-phthalic acid (PTA), the amounts of PC and PET MPs in the environmental samples were quantified. Recoveries of 87.2-97.1% were obtained for the PC and PET plastics particles spiked in the landfill sludge. The method was successfully applied to determine the occurrence of PC and PET MPs in the samples of sludge, marine sediments, indoor dust, digestive residues in mussel and clam, as well as in sea salt and rock salt. High concentrations of 246 and 430 mg/kg were determined for PC and PET type MP in an indoor dust, respectively. In addition, 63.7 mg/kg of PC and 127 mg/kg of PET were detected in the digestive residues of a clam.

Lei Wang, Junjie Zhang, Shaogang Hou, and Hongwen Sun, Environ. Sci. Technol. Lett., Just Accepted Manuscript, November 2, 2017

Dechlorane Plus induces oxidative stress and decreases cyclooxygenase activity in the blue mussel

Dechlorane Plus (DP) is a chlorinated flame retardant used mainly in electrical wire and cable coating, computer connectors, and plastic roofing materials. Concentrations of DP (syn and anti isomers) are increasingly being reported in aquatic ecosystems worldwide. However, there is exceedingly little information on the exposure-related toxicity of DP in aquatic organisms, especially in bivalves. The objective of this study was to investigate the in vivo and in vitro effects of DP exposure on histopathology, lipid peroxidation (LPO) levels, cyclooxygenase (COX) activity, phagocytosis capacity and efficiency, and DNA strand breakage in the blue mussel (Mytilus edulis) following a 29 days exposure (0.001, 0.01, 0.1 and 1.0 μg DP/L). Blue mussels accumulated DP in muscle and digestive gland in a dose-dependent manner. LPO levels in gills were found to increase by 82% and 67% at the 0.01 and 1.0 μg DP/L doses, respectively, while COX activity in gills decreased by 44% at the 1 μg/L dose. No histopathological lesion was found in gonads following DP exposure. Moreover, no change in hemocyte DNA strand breakage, phagocytosis rate, and viability was observed following DP exposure. Present study showed that toxicity of DP may occur primarily via oxidative stress in the blue mussel and potentially other bivalves, and that gills represent the most responsive tissue to this exposure.

Pierre-Luc Gagné, Marlène Fortier, Marc Fraser and al., Aquatic Toxicology, Volume 188, July 2017, Pages 26-32

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Fate and stability of polyamide-associated bacterial assemblages after their passage through the digestive tract of the blue mussel Mytilus edulis

We examined whether bacterial assemblages inhabiting the synthetic polymer polyamide are selectively modified during their passage through the gut of Mytilus edulis in comparison to the biopolymer chitin with focus on potential pathogens. Specifically, we asked whether bacterial biofilms remained stable over a prolonged period of time and whether polyamide could thus serve as a vector for potential pathogenic bacteria. Bacterial diversity and identity were analysed by 16S rRNA gene fingerprints and sequencing of abundant bands. The experiments revealed that egested particles were rapidly colonised by bacteria from the environment, but the taxonomic composition of the biofilms on polyamide and chitin did not differ. No potential pathogens could be detected exclusively on polyamide. However, after 7 days of incubation of the biofilms in seawater, the species richness of the polyamide assemblage was lower than that of the chitin assemblage, with yet unknown impacts on the functioning of the biofilm community.

Katharina Kesy, Alexander Hentzsch, Franziska Klaeger, Sonja Oberbeckmann, Stephanie Mothes, & Matthias Labrenz, Marine Pollution Bulletin, Volume 125, Issues 1–2, 15 December 2017, Pages 132-138

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Adherence of microplastics to soft tissue of mussels: A novel way to uptake microplastics beyond ingestion

Microplastic pollution is recognized as an emerging threat to aquatic ecosystems. One of the main environmental risks associated with microplastics is their bioavailability to marine organisms. Up to date, ingestion has been widely accepted as the sole way for the animals to uptake microplastics. Nevertheless, microplastics have also been found in some organs which are not involved in the process of ingestion. We hypothesize that the animal might uptake microplastics through adherence in addition to ingestion. To test this hypothesis, we collected mussels from the fishery farms, conducted exposure/clearance experiments and analyzed the accumulation of microplastics in specific organ of mussels. Our studies clearly showed the uptake of microplastic in multiple organs of mussels. In the field investigations, we found that the abundance of microplastic by weight but not by individual showed significant difference among organs, and the intestine contained the highest level of microplastics (9.2 items/g). In the uptake and clearance experiment, the accumulation and retention of microfibers could also be observed in all tested organs of mussels including foot and mantle. Our results strongly suggest that adherence rather than ingestion led to the accumulation of microplastics in those organs which are not involved in ingestion process. To our best knowledge, it is the first time to propose that adherence is a novel way for animals to uptake microplastics beyond ingestion. This new finding makes us rethink about the bioavailability, accumulation and toxicity of microplastics to aquatic animals.

Prabhu Kolandhasamy, Lei Su, Jiana Li, Xiaoyun Qu, Khalida Jabeen, Huahong Shi, Science of The Total Environment, Volumes 610–611, 1 January 2018, Pages 635-640

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