Holes on surfaces of the weathered plastic fragments from coastal beaches

Spectral analysis of environmental microplastic polyethylene (PE) using average spectra

In this study, microplastic samples from surface seawater of Tokyo Bay were collected, polyethylene (PE) microplastics were used to calculate carbonyl index (CI), and average spectra of PE were analyzed and compared with a previous study applying agitation during chemical treatment. It was found that PE and polypropylene (PP) were the predominant polymer type in the samples. Among PE samples, fragments were the most commonly observed shape, with white being the dominant color. Deviations were found in the average spectra among different shapes and colors when compared to the standard PE spectrum. A comparison of the average spectra between the two datasets suggests that pronounced peaks related to oxidation are most likely resulted from agitation during the chemical treatment. Additionally, it was found a closer spectral resemblance between the sample spectra and the spectrum of standard sample of oxidized PE (PEOx) than with the standard PE spectrum, suggesting that using the oxidized PE as a reference spectrum might be more effective for identification. These findings highlight the complex factors affecting the spectral properties of microplastics and highlight the importance of understanding these variations to enhance the accuracy of microplastic identification workflows and understanding of environmental fate of microplastics.

Microplastics in beach sediments of the Azores archipelago, NE Atlantic

Oceanic islands are exposed to plastic debris that has accumulated in the open ocean, particularly in the subtropical gyres. This study investigates the abundance and typology of microplastics (from 0.1 to 5 mm) on 19 sandy beaches spread across 8 oceanic islands of the Azores archipelago. Between January and April 2016, a total of 341 particles retrieved from all beaches, were identified as microplastics. The highest concentration (50.19 ± 21.93 particles kg-1 dw) was found in Terceira Island. Beach morphology and grain size were important factors explaining microplastic concentration. Fibres were the most dominant morphology recovered (80.9 %), followed by fragments (12.3 %). Fourier transform infrared spectroscopy (FTIR) revealed that 41 % of the fibres consisted of polyester and 60 % of the fragments were polyethylene. This research underlines the widespread contamination of microplastics in oceanic islands of the Atlantic Ocean.

Analysis of micro(nano)plastics based on automated data interpretation and modeling: A review

The widespread presence of micro(nano)plastics (MNPs) in the environment threatens ecosystem integrity, and thus, it is necessary to determine and assess the occurrence, characteristics, and transport of MNPs between ecological components. However, most analytical approaches are cost- and time-inefficient in providing quantitative information with sufficient detail, and interpreting results can be difficult. Alternative analyses integrating novel measurements by imaging or proximal sensing with signal processing and machine learning may supplement these approaches. In this review, we examined published research on methods used for the automated data interpretation of MNPs found in the environment or those artificially prepared by fragmenting bulk plastics. We critically reviewed the primary areas of the integrated analytical process, which include sampling, data acquisition, processing, and modeling, applied in identifying, classifying, and quantifying MNPs in soil, sediment, water, and biological samples. We also provide a comprehensive discussion regarding model uncertainties related to estimating MNPs in the environment. In the future, the development of routinely applicable and efficient methods is expected to significantly contribute to the successful establishment of automated MNP monitoring systems.

Evidence of microplastics accumulation in the gills and gastrointestinal tract of fishes from an estuarine system in Ghana

The contamination of aquatic environments by microplastics (MPs) and their subsequent ingestion by fish continues to be a universal ecological challenge. Although numerous studies have been conducted on the accumulation of MPs by fishes globally, not much work has been done within the major estuaries along the Atlantic Coast. This study explored and characterized microplastics in the gills and gastrointestinal tract in 98 specimens of 10 fish taxa (Sarotherodon melanotheron, Pseudotolithus senegalensis, Gobionellus occidentalis, Ethmalosa fimbriata, Chrysichthys nigrodigitalus, Elops lacerta, Mugil bananesis, Cynoglossus senegalensis, Apsilus fuscus and Galeoides decadactylus) from the Pra Estuary, Ghana. The gastrointestinal contents of the fish were extracted, analysed and characterized using a stereomicroscope fitted with an Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR). A total of 529 MP particles were found in the fishes. C. nigrodigitalus recorded the highest MP levels in the gills with an average of 4.83 ± 2.08 items/individual whiles S. melanotheron recorded the highest in the gastrointestinal tract at 9.83 ± 4.63 items/individual. Within the fish, transparent fibrous MPs of size <0.5 mm were the dominate types found. A vertical prevalence of MPs was observed across the feeding and habitat preference of the species suggesting a possible linkage with the ecological niche of fishes. Our findings further demonstrate the need for advance studies on the impacts and level of threat microplastic accumulation pose to the sampled fishes and potential consumers.

Interactions between microplastics and insects in terrestrial ecosystems-A systematic review and meta-analysis

The presence of microplastics (MPs) in terrestrial ecosystems has been confirmed worldwide. Due to their widespread distribution and diversity in habitats, insects will readily interact with MPs via various pathways. Although the topic of MP-insect interactions is still in the early stages of research, it is becoming increasingly important. We used a META approach with phylogenetic control and subgroup examination to summarize the evidence from both field and laboratory experiments in quantitative form. The field evidence suggests that insects can take and transfer MPs along food chains via ingestion and adherence. Also, they are active in the bio-fragmentation of MPs and the generation of secondary pollutants. The exposure to MPs impaired key biological traits of insects, mainly their behavior and health, such as reducing climbing ability and increasing oxidative stress. In terms of exposure conditions, the small-sized MPs can induce more severe effects on the insects, while the insect response to MPs was not significantly reliant on exposure times or MP concentrations based on the current evidence available. We propose that insects not only play roles in the redistribution of MPs spatially and in food chains via bio-fragmentation but are also threatened by MPs. Our research deepens our understanding of the environmental risks posed by MPs in insect ecosystems.

Analysis of microplastics in ships ballast water and its ecological risk assessment studies from the Persian Gulf

Transport of ballast water is considered a significant vector for dispersion of different pollutants, including microplastics (MPs), throughout the world's oceans. However, there is limited information on MPs in ballast water. Size distribution, polymer type, and ecological risks of MPs in ballast water were investigated for the first time in this study. The mean levels of MPs in ballast water and seawater samples were 12.53 and 11.80 items/L, respectively. MPs with a size category of 50-300 μm was the most abundant. Fiber, black, and polycarbonate (PC) were the predominant shape, color, and polymer type of identified MPs in ballast water and seawater, respectively. The pollution load index (PLI), hazard index (HI), and risk quotient (RQ) indicated high levels of MP pollution, potentially indicating an ecological risk. These findings increase our understanding of the major sources (such as ballast water), transportation routes, and related ecological risks of MPs to marine ecosystems.

Plastic and paint debris in marine protected areas of Peru

Contamination with anthropogenic debris, such as plastic and paint particles, has been widely investigated in the global marine environment. However, there is a lack of information regarding their presence in marine protected areas (MPAs). In the present study, the abundance, distribution, and chemical characteristics of microplastics (MPs; <5 mm), mesoplastics (MePs; 5-25 mm), and paint particles were investigated in multiple environmental compartments of two MPAs from Peru. The characteristics of MPs across surface water, bottom sediments, and fish guts were similar, primarily dominated by blue fibers. On the other hand, MePs and large MPs (1-5 mm) were similar across sandy beaches. Several particles were composite materials consisting of multiple layers confirmed as alkyd resins by Fourier-transformed infrared spectroscopy, which were typical indicators of marine coatings. The microstructure of paint particles showed differentiated topography across layers, as well as different elemental compositions. Some layers displayed amorphous structures with Ba-, Cr-, and Ti-based additives. However, the leaching and impact of potentially toxic additives in paint particles require further investigation. The accumulation of multiple types of plastic and paint debris in MPAs could pose a threat to conservation goals. The current study contributed to the knowledge regarding anthropogenic debris contamination in MPAs and further elucidated the physical and chemical properties of paint particles in marine environments. While paint particles may look similar to MPs and MePs, more attention should be given to these contaminants in places where intense maritime activity takes place.

A Hidden Pathway for Human Exposure to Micro- and Nanoplastics-The Mechanical Fragmentation of Plastic Products during Daily Use

In numerous environmental compartments around the world, the existence of micro- and nanoplastics (MNPs) in the environment has been verified. A growing number of studies have looked at the interaction between MNPs and human activities due to the risks they may pose to humans. Exposure pathways are key factors in measuring MNPs risks. However, current research largely ignores the contribution of mechanical fragmentation pathways to MNPs exposure during the daily use of plastic products. Our critical review demonstrated the research gap between MNP fragmentation and risk assessments via a network analysis. The release of fragmented MNPs and their properties were also described at various scales, with emphasis on environmental stressors and mechanical fragmentation. In the scenarios of daily use, plastic products such as food packaging and clothing provide acute pathways of MNPs exposure. The release tendency of those products (up to 102 mg MNPs) are several orders of magnitude higher than MNPs abundances in natural compartments. Despite the limited evidence available, waste recycling, landfill and municipal activities represented long-term pathways for MNPs fragmentation and point sources of MNPs pollution in environmental media. Assessing the health effects of the fragmentation process, unfortunately, is further hampered by the current absence of human exposure impact assessments for secondary MNPs. We proposed that future studies should integrate aging evaluation into risk assessment frameworks and establish early warning signs of MNPs released from plastic products.