Spatial monitoring of microplastics in environmental matrices from Galway Bay, Ireland.

Microplastic concentrations have been reported in a variety of environmental matrices and organisms across the world. Assessments of environmental concentrations are essential to understand trends and ensure decision-making processes that reduce environmental pressure. In this study, a combined sampling approach to surface waters, benthic sediments and biota in Galway Bay, Ireland, was carried out. Average concentrations of microplastics in surface waters were 1.42 ± 0.33 MPs m-3, in biota were 4.46 ± 0.36 MPs ind-1 and in benthic sediments were 5.60 ± 1.54 MPs kg-1. The diversity of polymers, microplastic types and colours were more abundant in surface waters and biota, when compared to benthic sediments. Integrated assessments of microplastics that follow existing monitoring programmes are essential to understand environmental trends. This work contributes to provide valuable information to descriptor 10 of the Marine Strategy Framework Directive in Ireland.

Deep Sea Microplastic Pollution Extends Out to Sediments in the Northeast Atlantic Ocean Margins.

Microplastics are ubiquitous emerging contaminants found in every habitat surveyed, building upon international databases globally. Costs and accessibility often correlate to few deep sea sediment surveys, restricting the number of stations within a given sampling area. An extensive survey of the Porcupine Seabight, Porcupine Bank, the Goban Spur, and south-western canyons resulted in identifying microplastics in deep sea sediment surface layers from 33 of the 44 stations sampled (75%), with a total of 83 particles (74 synthetic and 9 natural) recorded. No microplastic hotspots were identified, and abundances (kg d.w.-1) were not correlated with distance from land, depth, or the presence of macrolitter on the seafloor. Understanding the sources of deep sea microplastics, such as marine traffic, is crucial to developing effective mitigation strategies as well as further monitoring campaigns targeting microplastic pollution in areas with significant deep sea biodiversity such as the Porcupine Seabright.

Plastics, prawns, and patterns: Microplastic loadings in Nephrops norvegicus and surrounding habitat in the North East Atlantic.

The presence of microplastics (MPs), a contaminant of emerging concern, has attracted increasing attention in commercially important seafood species such as Nephrops norvegicus. This species lend themselves well as bioindicators of environmental contamination owing to their availability, spatial and depth distribution, interactions with seafloor sediment and position in the ecosystem and food chain. This study assesses the abundance of MPs in N. norvegicus and in benthic sediments across six functional units in the North East Atlantic. Assessment of the relationship between MP abundance in N. norvegicus, their biological parameters and their surrounding environment was examined. Despite the lack of statistical significance, MP abundances, size, shape, and polymer type recorded in N. norvegicus mirrored those found in the surrounding environment samples. The three main polymers identified in both organisms and sediment were polystyrene, polyamide (nylons), and polypropylene. The level of MP contamination in N. norvegicus could be related to local sources, with relatively low abundances recorded in this study for the North East Atlantic in comparison to other regional studies. Furthermore, larger organisms contained a lower abundance of MPs, demonstrating no accumulation of MPs in N. norvegicus. Based on the results of this study, data on MP ingestion could be used to study trends in the amount and composition of litter ingested by marine animals towards fulfilling requirements of descriptor 10 of the Marine Strategy Framework Directive.

Assessing microplastic distribution within infaunal benthic communities in a coastal embayment.

Marine anthropogenic litter is increasing in prevalence in both the marine environment and its inhabitants. This study assesses the levels of anthropogenic microplastics in benthic infauna from 20 subtidal stations in Galway Bay, Ireland. Microplastics were removed from the organisms using an alkaline digestion (KOH) and their synthetic origin was confirmed by µFTIR spectroscopic analysis. The average number of microplastics recorded for all organisms was 0.79 ± 1.14 particles individual-1, similar to previously published results on subtidal fauna of the North Sea. Fibres were the dominant particle type (98%) and the majority were identified as natural (cellulose, cotton). Synthetic polymers identified included PVA (polyvinyl acetate), EPDM (synthetic rubber), PE (polyethylene) and PVC (polyvinyl chloride). Fibres less than 1 mm made up 55% of the recovered lengths. Colours recorded in the organisms were mainly blue and were reflective of the surrounding habitats. Of the five phyla collected, the highest incidence and uptake was associated with the Annelida. A significant difference in ingested MPs was only evident when depth (greater and less than 30 m) was considered as a factor. In addition, no significant differences were found between either the numbers of ingested MPs and phyla or feeding strategies. The results indicate that future studies should follow an ecosystem-based approach to monitor MPs levels in an area where specific bioindicator(s) have not been identified or are unsuitable.

Differences in microplastic abundances within demersal communities highlight the importance of an ecosystem-based approach to microplastic monitoring.

Plastic pollution is prevalent in all habitats and microplastic ingestion has been recorded in several different species examined to date. However, most studies have focused solely on commercial species. This study investigates microplastics (MPs) by assessing the levels present in a mixed demersal trawl at two sites in a coastal embayment. MPs were recovered from species' gastrointestinal tracts and polymers identified with µFTIR spectroscopic analysis. Particles recovered comprised 20% natural fibres. The majority of MPs were identified as PE, PVDF, and PETE. Results show an average MP range of 0.11-4.67 MPs individual-1. Fluctuating trendlines for MPs within species suggest that their bioavailability is influenced by several factors. Individual species show significant differences in ingested MP between trawls; however, when the entire trawl community is assessed there is no significant difference between sites. These results suggest that future studies should follow an ecosystem-based approach to monitor MPs.

Floating microplastics in a coastal embayment: A multifaceted issue.

Floating microplastic debris at the ocean's surface represents about 1% of all plastics found in the environment, with the remainder thought to be either deposited along the coast or sinks to the bottom of the ocean. This exploratory research on a coastal embayment in the Northeast Atlantic Ocean assesses floating microplastic densities and the potential influence of wind. A total of 1182 floating microplastic particles were retrieved from a total surface seawater volume of 2039.86 m3. The average microplastic density (0.56 ± 0.33 MP m-3) is based on a sample of 20 manta trawls. This study reports primary microplastics (microbeads) floating in Irish coastal waters for the first-time. Compared to similar bays in Europe, Galway Bay has a similar microplastic density range. Microplastics in surface waters are a multifaceted issue therefore, multiple types of sample collection along with associated environmental variables are recommended for coastal monitoring purposes.

Microplastics in Galway Bay: A comparison of sampling and separation methods.

Microplastics, an emerging pollutant, are recognised as having a ubiquitous distribution in the environment. Currently several benthic sampling tools are being employed to collect subtidal marine sediment, however, there are no comparative studies on the efficiency of these tools to sample for microplastics or the subsequent extraction methods of microplastics from these marine sediments. This study addresses these knowledge gaps by comparing commonly applied benthic sampling tools (Van Veen grab, box corer, gravity corer) and a variety of density separation methods (elutriation column, sodium chloride solution, sodium tungstate dihydrate solution) for microplastic collection and processing. Each sampling tool was tested at the same station and the collected sediment was used to assess the extraction performance for the different density separation techniques. No statistically significant differences were found between the concentrations of microplastics extracted for any of the sampling tools. However, there were significant differences between the density separation methods using sodium tungstate dihydrate and sodium chloride solution and the elutriation method. This preliminary study provides evidence that the sampling tools tested are both suitable and proficient at determining the abundance of microplastics in sediments. Sodium tungstate dihydrate proved to be a novel and feasible option for dense liquid separation of microplastics in subtidal marine sediments. These results will allow for more confidence in data quality when comparing future surveys applying different benthic sampling tools.