Continuous Exposure to Microplastics Does Not Cause Physiological Effects in the Cultivated Mussel Perna perna

The environmental impact of microplastics is a challenging theme, especially under realistic experimental conditions. We investigated physiological responses to 0.1–1.0 μm PVC particles intake by the mussel Perna perna after a relative long-term exposure (90 days) at a less extreme concentration compared with previous studies (0.125 g/L). Microplastic intake was inferred by the presence of PVC in the feces of mussels, and physiological damages were assessed through ingestion rate, assimilation efficiency, growth rate, cellular and molecular biomarkers (lysosomal integrity, lipid peroxidation, and DNA damage), and condition index. All physiological responses showed nonsignificant effects of the microplastics on the exposed mussels. We suggest that, despite the experimental concentration of microplastics, mussels were able to acclimate to the exposure through their abilities for long-term recovery and tolerance to stresses. These data have positive implications for environmental health and in terms of human food resource because mussel farming is a worldwide practice that heavily relies on plastic materials, increasing the chances of microplastic exposure and mussels contamination.

Marina F. M. Santana,Fabiana T. Moreira, Camilo D. S. Pereira, Denis M. S. Abessa, Alexander Turra, Archives of Environmental Contamination and Toxicology, P; 1-11, 19/01/2018

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Threat of plastic ageing in marine environment. Adsorption/desorption of micropollutants

Ageing of various plastics in marine environment was monitored after immersion of two synthetic (polyvinylchloride, PVC, and polyethylene terephthalate, PET) and one biodegradable (poly(butylene adipate co-terephtalate), PBAT) plastics for 502 days in the bay of Lorient (Brittany, France). Data analysis indicates that aged PVC rapidly releases estrogenic compounds in seawater with a later adsorption of heavy metals; PET undergoes a low weakening of the surface whereas no estrogenic activity is detected; PBAT ages faster in marine environment than PVC. Aged PBAT exhibits heterogeneous surface with some cavities likely containing clay minerals from the chlorite group. Besides, this degraded material occasionally shows a high estrogenic activity. Overall, this study reports, for the first time, that some aged plastics, without being cytotoxic, can release estrogenic compounds in marine environment.

Mikaël Kedzierski, Mélanie D’Almeida, Anthony Magueresse and al., Marine Pollution Bulletin, Volume 127, February 2018, Pages 684-694

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Effects of dietary polyvinylchloride microparticles on general health, immune status and expression of several genes related to stress in gilthead seabream (Sparus aurata L.)

It is a long-recognized fact that marine plastic debris contaminates the oceans and seas of the entire world. Even though their effects on the aquatic biota are not well documented or understood. The effects of dietary polyvinylchloride microparticles (PVC-MPs) on the general health, immune status and some stress markers were studied using gilthead seabream (Sparus aurata) as a model of marine fish. Thirty specimens were randomly placed in three running sea water aquaria and fish in each aquarium received an experimental diet containing 0 (control), 100 or 500 mg kg−1 of PVC-MPs for 30 days. Metabolic parameters in serum indicated that the dietary intake of PVC-MPs negatively affected several vital organs. Humoral immune parameters were determined in serum and skin mucus. Cellular immune parameters were determined in head-kidney leucocytes. Concomitantly, the expression of different genes related to stress was studied in head-kidney and liver. Regarding head-kidney gene expression, prdx5 was significantly decreased by PVC-MPs intake for 15 and 30 days, respect to the values found in control fish. On the other hand, the expression of prdx1 and prdx3 were significantly increased by the PVC-MPs intake during 15 and 30 days, compared with the values found in control fish. Furthermore, the expression of hsp90 and ucp1 genes decreased and increased, respectively, in the liver of fish fed 500 mg kg−1 of PVC-MPs for 30 days. Although ingestion of PVC-MPs provoked few significant effects (mostly increases) in the main immune activities of gilthead seabream compared with the values found in control fish, PVC-MPs are recognized by the fish as stressors. Continued exposure of fish to high concentrations of PVC-MPs could have a negative impact on fish physiology due to the chronic stress produced.

Cristóbal Espinosa, Alberto Cuesta, María Ángeles Esteban, Fish & Shellfish Immunology, Vol. 68, Sept. 2017

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Characterization and Analysis of Microplastics

This book aims to fulfill the gap on the existence of published analytical methodologies for the identification and quantification of microplastics. This overview includes the following main topics: introduction to the fate and behavior of microplastics in the environment, assessment of sampling techniques and sample handling, morphological, physical, and chemical characterization of microplastics, and the role of laboratory experiments in the validation of field data.

The characterization and analysis of microplastics is a hot topic considering the current need for reliable data on concentrations of microplastics in environmental compartments. This book presents a comprehensive overview of the analytical techniques and future perspectives of analytical methodologies in the field.

Comprehensive Analytical Chemistry, Volume 75, Pages 1-286 (2017), edited by Teresa A.P. Rocha-Santos and Armando C. Duarte, ISBN: 978-0-444-63898-4

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Determination of microplastic polyethylene (PE) and polypropylene (PP) in environmental samples using thermal analysis (TGA-DSC)

Microplastics are increasingly detected in the environment and the consequences on water resources and ecosystems are not clear to date. The present study provides a cost-effective and straightforward method to determine the mass concentrations of polymer types using thermal analysis. Characteristic endothermic phase transition temperatures were determined for seven plastic polymer types using TGA-DSC. Based on that, extracts from wastewater samples were analyzed.

Results showed that among the studied polymers, only PE and PP could be clearly identified, while the phase transition signals of the other polymers largely overlap each other. Subsequently, calibration curves were run for PE and PP for qualitative measurements. 240 and 1540 mg/m3 of solid material (12µm to 1mm) was extracted from two wastewater effluent samples of a municipal WWTP of which 34% (81 mg/m3) and 17% (257 mg/m3) could be assigned to PE, while PP was not detected in any of the samples. The presented application of TGA-DSC provides a complementary or alternative method to FT-IR analyses for the determination of PE and PP in environmental samples.

Marius Majewsky, Hajo Bitter, Elisabeth Eiche, Harald Horn, Science of The Total Environment, Volume 568, 15 October 2016, Pages 507–511

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Microplastics on beaches: ingestion and behavioural consequences for beachhoppers

Microplastics are ubiquitous in the marine environment worldwide, and may cause a physical and chemical risk to marine organisms. Their small size makes them bioavailable to a range of organisms with evidence of ingestion at all levels of the marine ecosystem. Despite an increasing body of research into microplastics, few studies have explored how consumption changes complex behaviours such as predator avoidance and social interactions. Pollutant exposure can result in alterations in behaviour that not only leads to sub optimal conditions for individual organisms but may also serve as a warning sign for wider effects on a system. This research assessed the impacts of microplastics on the ecology of coastal biota using beachhoppers (Platorchestia smithi) as model organisms. We exposed beachhoppers to marine-contaminated microplastics to understand effects on survival and behaviour. Beachhoppers readily ingested microplastics, and there was evidence for accumulation of microplastics within the organisms. Exposure tests showed that microplastic consumption can affect beachhopper survival. Individuals also displayed reduced jump height and an increase in weight, however, there was no significant difference in time taken to relocate shelter post disturbance. Overall, these results show that short-term ingestion of microplastics have an impact on survival and behaviour of P. smithi. A reduction in the capacity for beachhoppers to survive and function may have flow on effects to their local environment and higher trophic levels.

, Culum Brown, Jane E. Williamson, Mar Biol (2016) 163: 199

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Suspended micro-sized PVC particles impair the performance and decrease survival in the Asian green mussel Perna viridis

Marine bivalves are known to ingest microplastics, but information on the consequences for their physiological performance is limited. To investigate a potential exposure pathway that has not yet been addressed, we mimicked the resuspension of microplastics from the sediment in a laboratory exposure experiment. For this, we exposed the Asian green mussel Perna viridis to 4 concentrations (0 mg/l, 21.6 mg/l, 216 mg/l, 2160 mg/l) of suspended polyvinylchloride (PVC) particles (1–50 μm) for two 2-hour-time-periods per day. After 44 days, mussel filtration and respiration rates as well as byssus production were found to be a negative function of particle concentration. Furthermore, within 91 days of exposure, mussel survival declined with increasing PVC abundance. These negative effects presumably go back to prolonged periods of valve closure as a reaction to particle presence. We suggest that microplastics constitute a new seston component that exerts a stress comparable to natural suspended solids.

Sinja Elena Rist, Khoirunnisa Assidqi, Neviaty Putri Zamani and al.,  Marine Pollution Bulletin, Volume 111, Issues 1–2, 15 October 2016, Pages 213–220

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