Microplastics doi: 10.3390/microplastics3030022

Authors: Byeong-Kyu Min Chon-Rae Cho Hwi-Su Cheon Ho-Young Soh Hyeon-Seo Cho

Microplastic distribution surveys centered on Korea’s Gwangyang Bay and southern coastal waters. Gwangyang Bay seawater averaged 3.17 ± 1.23 particles/L, and sediments averaged 462.4 ± 143.9 particles/kg. The southern coastal seawater averaged 0.10 ± 0.09 particles/L, and the sediments averaged 50.6 ± 29.7 particles/kg. Microplastics flowing from land, through physical modeling of ocean currents in Gwangyang Bay and southern coastal waters, pass through the Yeosu Strait and flow into the southern coastal waters. At the same time, it is judged that the southern coastal waters showed somewhat lower abundance than the Gwangyang Bay waters because they move toward the Korean Strait due to the Jeju warm current water and Tsushima current water, strongly generated in summer. In addition, the seawater microplastic abundance showed a higher abundance than that on the site adjacent to the land in the southern coastal waters, which is the study area. On the other hand, the results for sediment microplastic abundance were opposite to the surface seawater microplastic results. Therefore, it is judged that entering one source of pollution does not affect the distribution of microplastics in Gwangyang Bay and southern coastal waters, but rather this occurs in different forms.

Microplastics doi: 10.3390/microplastics3020021

Authors: Lori Shelton Pieniazek Michael L. McKinney Jake A. Carr Lei Shen

The study of microplastics (MPs) in soils is impeded by similarities between plastic and non-plastic particles and the misidentification of MP by current analytical methods such as visual microscopic examination. Soil MPs pose serious ecological and public health risks because of their abundance, persistence, and ubiquity. Thus, reliable identification methods are badly needed for scientific study. One possible solution is UV–Vis–NIR spectroscopy, which has the ability to rapidly identify and quantify concentrations of soil microplastics. In this study, a full-range, field portable spectrometer (350–2500 nm) with ultra-high spectral resolution (1.5 nm, 3.0 nm, and 3.8 nm) identified three types of common plastics: low-density polyethylene (LDPE), polyvinyl chloride (PVC), and polypropylene (PP). Three sets of artificially MP-treated vermiculite soil samples were prepared for model prediction testing and validation: 150 samples for model calibration and 50 samples for model validation. A partial least square regression model using the spectral signatures for quantification of soil and MP mixtures was built with all three plastic polymers. Prediction R2 values of all three polymers showed promising results: polypropylene R2 = 0.943, polyvinyl chloride R2 = 0.983, and polyethylene R2 = 0.957. Our study supports previous work showing that combining ultra-high-resolution UV–Vis–NIR spectrometry with quantitative modeling can improve the accuracy and speed of MP identification and quantification in soil.

Microplastics doi: 10.3390/microplastics3020020

Authors: Luís André Mendes Ricardo Beiras Jorge Domínguez

The availability of compostable plastic bags has increased greatly in the past few years, as it is perceived that this type of bags will be degraded after disposal. However, there are some knowledge gaps regarding the potential effects on the soil ecosystems. We assessed the rate of degradation of samples of four different types of commercial compostable bags in vermicomposting systems with the earthworm species Eisenia andrei. We also evaluated the biological response of E. andrei (survival and reproduction) to microplastics (MPs) from fragments of the plastic bags (<2000 µm) and assessed seedling emergence in common garden cress (Lepidium sativum L.) exposed to micronized plastic (<250 µm) and the respective leachate, following OECD and ISO guidelines, respectively. The rate of degradation differed significantly depending on the type of plastic rather than the substrate in the vermicomposting system. This finding suggests that the degradation process is more dependent on the microbial community colonizing the different plastic types than on earthworm activity. Regarding the biological response of the soil system, L. sativum seedling emergence was not significantly affected; however, earthworm reproduction was affected, suggesting that although compostable, some of the formulations may potentially be toxic to soil fauna.

Microplastics doi: 10.3390/microplastics3020019

Authors: Johannes Wolfgang Neupert Daniel Venghaus Matthias Barjenbruch

The environmental impact of tire wear emissions has become increasingly apparent, and efforts to reduce their impact on the environment are on the rise. To minimise the generation of tire wear, it is essential to consider the influencing factors. However, as it cannot be entirely prevented, measures to reduce immissions are also necessary. This paper summarises possible measures derived from the literature, stakeholder workshops, and the authors’ own conclusions, taking into account the different perspectives: tire, vehicle, road, sustainable mobility and emissions treatment. The presentation of the entry paths of tire wear into the environment and the hotspots of generation can be used to prioritise reduction measures. Measures should be implemented at a political level, technical solutions applied, and awareness raised among the general public. It is evident that reducing tire wear is a complex task that requires a transdisciplinary approach.

Microplastics doi: 10.3390/microplastics3020018

Authors: Katie Stallings Kimberly J. Zaccaria Megan Riccardi Gregory M. Zarus Gaston Casillas

In the last few years, microplastics research has exploded, with the field exploring new procedures and techniques that focus on a variety of scientific and policy issues. As there are not standardized definitions for many terms in the field, including the term microplastic itself, researchers utilize the same labels to describe different aspects of microplastic pollution. Here we provide a visual tool, called a Hub for Interactive Literature (HIL), to assist researchers in identifying and targeting specific literature. Currently, there are four Hubs for Interactive Learning (HILs) corresponding to previously published reviews, including a scoping review of microplastics literature as well as three reviews examining the human exposure and health effects of microplastics, the unique liver carcinogenicity of polyvinyl chloride (PVC) microplastics, and micro and nanoplastics found in the air. The HILs incorporate all of the literature used to produce the corresponding reviews. A couple of advantages that HILs provide in their capacity as a supportive instrument are the filtering options and easily accessed original references. This tool can be leveraged by researchers to rapidly review microplastics research and isolate specific subtopics of interest to develop new conclusions and quickly identify data gaps. We give an in-depth look at the HIL corresponding to a scoping review of microplastics literature to exhibit the novel functionality and advantages of this exciting tool. We demonstrate a novel world map of the literature to show that microplastics are a global scientific and public health issue. The map offers the additional functionality of filtering the references by country. We also provide a brief description of the current HILs to show the flexibility and personalization available when using this method.

Microplastics doi: 10.3390/microplastics3020017

Authors: Philipp Lau Julia Stein Luisa Reinhold Matthias Barjenbruch Tim Fuhrmann Ingo Urban Katrin Bauerfeld Andrea Holte

Microplastic (MP) has emerged as a significant environmental challenge due to increased plastic production and its widespread presence in the environment. This study aimed to assess MP concentrations throughout the treatment process at nine wastewater treatment plants (WWTPs) in Germany, from influent to effluent. A customized sampling technique was employed, followed by field and laboratory preparation and the quantification of polymers (PE, PP, PS, PMMA, and PET) using TED-GCMS. MP concentrations decreased progressively in the WWTPs, with influent concentrations ranging from 2.5 to 13.6 mg/L. Effluent concentrations in the conventional WWTPs ranged from 0.001 to 0.051 mg/L, while advanced treatment via filtration yielded concentrations below the limit of quantification at 0.005 mg/L. All tested of the WWTPs demonstrated an over 99% removal efficiency for microplastics. Despite effective retention by the WWTPs, a critical evaluation of the results is necessary. There is a need to optimize existing technologies and enhance the standardization of sampling, processing, and measurement methods, as well as intensify efforts towards creating preventive measures to reduce plastic emissions.

Microplastics doi: 10.3390/microplastics3020016

Authors: Gwanghee Lee Jaeheon Jung Sangjun Moon Jihyun Jung Kyoungson Jhang

We introduce a novel microscopic image dataset augmented with segmentation and detection labels specifically designed for microplastic analysis in sewage environments. Recognizing the increasing concern over microplastics—particles of synthetic polymers smaller than 5 mm—and their detrimental effects on marine ecosystems and human health, our research focuses on enhancing detection and analytical methodologies through advanced computer vision and deep learning techniques. The dataset comprises high-resolution microscopic images of microplastics collected from sewage, meticulously labeled for both segmentation and detection tasks, aiming to facilitate accurate and efficient identification and quantification of microplastic pollution. In addition to dataset development, we present example deep learning models optimized for segmentation and detection of microplastics within complex sewage samples. The models demonstrate significant potential in automating the analysis of microplastic contamination, offering a scalable solution to environmental monitoring challenges. Furthermore, we ensure the accessibility and reproducibility 12 of our research by making the dataset and model codes publicly available, accompanied by detailed 13 documentation on GitHub and LabelBox.

Microplastics doi: 10.3390/microplastics3020015

Authors: Carol A. Smith Santosh Mandal Chunlei Fan Saroj Pramanik

Microplastics are tangible particles of less than 0.2 inches in diameter that are ubiquitously distributed in the biosphere and accumulate in water bodies. During the east-coast hot summers (23–29 °C) of 2021 and 2022, June through September, we captured copious amounts of the jellyfish Chrysaora chesapeakei, a predominant species found in the Patuxent River of the Chesapeake Bay in Maryland on the United States East Coast. We determined that their gelatinous bodies trapped many microplastics through fluorescent microscopy studies using Rhodamine B staining and Raman Spectroscopy. The chemical nature of the microplastics was detected using gas chromatography–mass spectroscopy headspace (SPME-GC-MS) and solvent extraction (GC-MS) methods through a professional commercial materials evaluation laboratory. Numerous plastic-affiliated volatile organic compounds (VOCs) from diverse chemical origins and their functional groups (alkanes, alkenes, acids, aldehydes, ketones, ethers, esters, and alcohols) along with other non-microplastic volatile organic compounds were observed. Our findings corroborate data in the available scientific literature, distinguishing our finding’s suitability.

Microplastics doi: 10.3390/microplastics3020014

Authors: Jack H. Prior Justine M. Whitaker Alexis M. Janosik

Primary consumers of microplastics are often zooplankton species such as the mysid shrimp, Americamysis bahia. Ingesting and interacting with these plastics can cause stress and lead to death. In the presence of some environmental stressors, gene expression may be altered without changing DNA sequences via the epigenetic methylation of the DNA. Mysid shrimp were exposed to 5-micrometer fluorescent polystyrene microbeads at different concentrations and different lengths of time. No significant effects were observed on mortality within 72 h, but mortality increased significantly thereafter. Microplastics were consumed by mysids and adhered to the mysid carapace and appendages. An ELISA-like (Enzyme-Linked Imuunosorbent Assay) colorimetric assay was employed to assess mysid DNA for differences in global percent methylation. No significant difference in the average percent methylated DNA nor difference in the number of methylation detections between treatments was found. This is one of few studies that has investigated DNA methylation effects due to microplastics-induced stress and the first study to detect DNA methylation in any member of the order Mysida.

Microplastics doi: 10.3390/microplastics3020013

Authors: Madjid Djouina Suzie Loison Mathilde Body-Malapel

The tremendous plastic production and poor post-use management are current and future sources of environmental and human contamination due to their degradation products: microplastics and nanoplastics (MNPLs). Methodological developments have allowed MNPLs to be detected in an increasing variety of human foods, as well as in stool and colonic mucosa. It was suggested early that the direct contact between MNPLs and intestinal tissues could represent a potential risk for human health. In order to assess this, over the last 3 years, numerous studies have evaluated the impact of MNPL ingestion on intestinal homeostasis in rodents. This comprehensive review reports the preclinical studies published between January 2021 and January 2024, and analyzes their contributions as well as their shortcomings. It shows that evidence is accumulating of the intestinal toxicity of spherical MNPLs, which lead to pro-inflammatory, pro-oxidative, barrier-disruptive and dysbiotic effects. However, the available literature has addressed only a minor part of the potential health issues of MNPLs. Many parameters contributing to MNPL toxicity need to be better taken into account in future studies. Particular attention should be paid to improve the representativeness of MNPLs, as well as to better consider the susceptibility factors of MNPL toxicity, generated especially by an underlying pathology or pathological imprinting.

Microplastics doi: 10.3390/microplastics3020012

Authors: Arthur Braun Harald Seitz

The usage of plastic and its decomposition products leads to their ubiquitous distribution, resulting in their uptake by all living beings, including humans. Polymethylmethacrylate (PMMA) is known as a biocompatible polymer and is used widely in medicine and dentistry, although recent findings have shown its induction of oxidative stress within cells. Worryingly, hardly any data exist investigating the uptake of PMMA particles by cells, the potential effects of these particles on cells and cell signaling pathways and their contributing factors. We assessed the uptake of PMMA beads via confocal microscopy after their incubation with HEK293, A549 and MRC5 cells. Through cell staining, we localized multiple PMMA beads within the cytosol of cells. No alterations regarding cell growth, cell morphology or cell division were found, implying no short-term toxicity towards human cells. Using a cAMP response element binding protein (CREB)-mediated reporter assay, we assessed whether internalized PMMA nanobeads alter cell signaling pathways after stimulation of the cells. CREB was chosen as a well-described transcription factor involved in various cellular processes. Our data led to the assumption that PMMA nano- and microbeads are internalized via endocytosis and end up in lysosomes within the cell cytosol. We concluded that differences regarding the surface composition of the PMMA nanobeads affect their potential to alter cell signaling. These findings emphasize the key role the surface composition plays regarding microplastics and their risks for human health, whereas the usage of medical-grade PMMA remains safe.

Microplastics doi: 10.3390/microplastics3010011

Authors: Valentina Phinikettou Iliana Papamichael Irene Voukkali Antonis A. Zorpas

Environmental pollution caused by microplastics has evolved into a global concern; however, limited knowledge exists about microplastics in soils due to the absence of standardized extraction methods. This research aimed to develop an inexpensive, rapid method with user-friendly and environmentally sustainable outcomes for microplastics retrieval. Three salt solutions (Sodium Chloride, Magnesium Sulfate, Sodium Hexametaphosphate) and an oil solution (canola oil) underwent evaluation for microplastics extraction through the flotation process due to the density and oleophilic properties of plastics. Four widely used plastic types, obtained through fragmentation using a grinding mill from clean new plastic containers or membranes, were subjected to analysis. The experimental procedures for microplastics retrieval varied among the evaluated solutions. Through a comprehensive multicriteria analysis, the saturated Sodium Chloride solution emerged as the optimal scenario for microplastics extraction, followed closely by the canola oil scenario. The recovery method utilizing Sodium Chloride demonstrated economic feasibility, safety, and reliability. This study provides valuable insights into an effective and sustainable approach for mitigating microplastic pollution in soil, offering a promising avenue for future environmental conservation efforts.

Microplastics doi: 10.3390/microplastics3010010

Authors: Mitra Nikpay Sayna Toorchi Roodsari

Microplastics (MPs), microscopic particles originating from plastic products, have emerged as a persistent environmental challenge, posing threats to both ecosystems and human health. Their omnipresence, extending from the highest mountains to the deepest oceans and infiltrating the bodies of humans and animals, requires urgent attention. In the face of escalating annual plastic production and inefficient waste management, where 79% of plastic production ends up in landfill sites or enters the environment, MPs multiply as its consequence. This emphasizes the urgent need for a comprehensive global framework that transcends borders to systematically address and control the growth of MPs. In response, our research conducts an in-depth investigation and proposes a seven-step strategy, providing a global perspective for mitigating microplastic pollution. The proposed approach begins with initial research steps and closes in predicting the remediation of areas impacted by microplastic pollution.

Microplastics doi: 10.3390/microplastics3010009

Authors: Jeffrey Ashley Amanda Pilat Ariana Ohlweiler Connor Ogden Owen Bradley Priya Modi Spencer Talbot Caya Smith Justin O’Pella Gulnihal Ozbay

Due to the prevalence of plastic pollution in coastal ecosystems, aquatic organisms are at high risk for accumulating microplastics (MPs). Filter-feeding bivalves, such as mussels and oysters, may be exposed to, and subsequently accumulate, MPs due to the high volume of water they pass through their bodies. This study assessed the levels of MPs within Atlantic ribbed mussels (Geukensia demissa), a common filter feeder found along the United States Atlantic Coast, from 12 sites within Rehoboth Bay, Indian River Bay, and Little Assawoman Bay, collectively known as the Delaware Inland Bays. Composited mussels from each site were digested using potassium hydroxide and filtered. Microplastics were physically identified, sorted based on color, and counted using a digital microscope. Microplastics, almost entirely dominated by synthetic microfibers, were found in all mussels well above laboratory blanks. Across all sites, 40% of microfibers were black, and 27% of fibers were clear. The composite concentrations of MPs ranged from 0.25 to 2.06 particles/g wet tissue, with a mean of 0.08 ± 0.06. In general, higher concentrations were found in mussels collected at sites that were adjacent to more urbanized land use versus those from rural sites. At two sites, individual mussels, in addition to composites, were analyzed and had MP concentrations ranging from 11 to 69 particles/mussel. This study represents the first evaluation of MPs in this ecologically important coastal species and suggests its viability as a biomonitoring species for microplastic pollution.

Microplastics doi: 10.3390/microplastics3010008

Authors: Melanie Fritz Lukas F. Deutsch Karunia Putra Wijaya Thomas Götz Christian B. Fischer

Microplastics (MPs) pose a significant risk to humans and animals due to their ability to absorb, adsorb, and desorb organic pollutants. MPs catchment from either sediments or water bodies is crucial for risk assessment, but fast and effective particle quantification of irregularly shaped particles is only marginally addressed. Many studies used microscopy methods to count MP particles, which are tedious for large sample sizes. Alternatively, this work presents an algorithm developed in the free software GNU Octave to analyze microscope images of MP particles with variable sizes and shapes. The algorithm can detect and distinguish different particles, compensate for uneven illumination and low image contrast, find high-contrast areas, unify edge regions, and fill the remaining pixels of stacked particles. The fully automatic algorithm calculates shape parameters such as convexity, solidity, reciprocal aspect ratio, rectangularity, and the Feret major axis ratio and generates the particle size distribution. The study tested low-density polyethylene particles with sizes of 50–100 µm and 200–300 µm. A scanning electron microscope image series analyzed with Octave was compared to a manual evaluation using ImageJ. Although the fully automatic algorithm did not identify all particles, the comprehensive tests demonstrate a qualitatively accurate particle size and shape monitoring applicable to any MPs, which processes larger data sets in a short time and is compatible with MATLAB-based codes.

Microplastics doi: 10.3390/microplastics3010007

Authors: Vyoma Jani Shenghua Wu Kaushik Venkiteshwaran

In recent years, the ubiquitous occurrence of plastic debris has become a significant environmental concern, posing considerable harm to our ecosystems. Microplastics (MPs) (1 μm–5 mm) and nanoplastics (NPs) (<1 μm) are noticeable in diverse forms, spreading throughout the environment. Notably, wastewater treatment plants (WWTPs) emerge as major contributors to the generation of MP and NP. Within these treatment plants, water influx from domestic and commercial sources carries a considerable load of MPs derived from items like fiber clothing, personal care products, and toothpaste. Lacking dedicated removal mechanisms, these MPs persist through the wastewater treatment process, ultimately entering natural water bodies and the soil environment. The novelty of this review lies in its detailed examination of contemporary methodologies for sampling, detecting, and eliminating MPs specifically from WWTPs. By critically assessing the efficacy of current removal techniques at various treatment stages, the review offers targeted insights into practical aspects of MP management in these facilities. As the study of micro/nano plastics is still in its early stages, this article aims to contribute by offering a comprehensive review of the methods utilized for plastic debris removal in both WWTPs and drinking water treatment plants (DWTPs). Furthermore, the article provides a comprehensive overview of the existing rules, regulations, and policies concerning MPs in the United States. This inclusion not only broadens the scope of the review but also establishes it as a valuable reference for understanding the regulatory framework related to MPs. This review uniquely combines a focused evaluation of WWTPs/DWTPs, an exploration of removal methods, and an examination of regulatory framework, making a different contribution to the review article. Through this review, we aim to enhance understanding and awareness of the multi-layered challenges posed by MPs, offering insights that can inform future research directions and policy initiatives.

Microplastics doi: 10.3390/microplastics3010006

Authors: Yuliya Logvina Isabel M. Matas Helena Ribeiro Luís Pinto da Silva Pedro Rodrigues João Leitão Joaquim Esteves da Silva

Micro- and nanoplastics (MNPs) are an important atmospheric aerosol constituent. However, there still needs to be a standard procedure for their sampling and size fractionation, which is an obstacle to the aggregation and critical analysis of results obtained by different research groups. This review focuses on the sampling and fractionation methodologies used for MNPs. Moreover, a streamlined, simplified methodology for sampling and fractionation is proposed.

Microplastics doi: 10.3390/microplastics3010005

Authors: Oskar Świątek Agnieszka Dąbrowska

Microfibers (MFs) are one of the most common and hazardous forms of microplastic found in the aquatic environment. The methods of collecting and analyzing MFs released during washing have to be developed and standardized to understand and model the process of microfibers’ emission better. This study tests a new, innovative method to check if laundry fiber sampling can be approached comprehensively. Pieces of synthetic materials (aged and new polyester, polyester-cotton blend) were placed in chromium-nickel filters envelope-like folded. Then, textile weathering during washing was monitored by the quality and quantity of fibers found directly on the filter surface. Laundry parameters like temperature, detergent presence, and filter size were changed, and results were monitored by Fourier-transform infrared spectroscopy (FTIR), a well-known standard in microplastic identification. In addition, ATR spectra were collected to characterize the materials in detail and evaluate their aging level. Spectroscopy can be used to detect and examine both mechanical and chemical degradation, and the collected microfibers can be assigned to the material they come from. Finally, a quantitative comparison of fibers released during different washing conditions can be used for the process optimization to minimize its environmental impact.

Microplastics doi: 10.3390/microplastics3010004

Authors: Stephanie Damaj Farah Trad Dennis Goevert Jeff Wilkesmann

Given the broad and intense use of plastic, society is being increasingly affected by its degradation and by-products, particularly by microplastics (MPs), fragments smaller than 5 mm in size, and nanoplastics (NPs), with sizes less than 1 µm. MPs and NPs may enter the body primarily through inhalation, consumption, and skin contact. Once ingested, MPs can penetrate tissues, deviating to other parts of the body and potentially affecting important cellular pathways such as nonconforming chemokine receptors that control the communication between the fetus and the mother. Consequently, the potential health harm induced via MP internalization is a major issue, evidenced by multiple studies demonstrating harmful consequences in diverse animal models and human cells. Here, an overview of the various modes of exposure to MPs and NPs is presented, including inhalation, placental transfer, ingestion, breastmilk consumption, and skin absorption, as well as placental and fetal toxicity due to plastic particles based on animal and in vitro studies. Though MPs in our environment are becoming more recognized, their developmental toxicity is still scarcely known. Besides negatively affecting pregnancy, MPs and NPs have been shown to potentially harm the developing fetus, given their ability to cross the placental barrier. Still, considerable gaps remain in our understanding of the dispersion and toxicity of these particles in the environment and the precise types of NPs and MPs bearing the greatest dangers. As a result, we advocate for larger-scale epidemiological investigations, the development of novel approaches for measuring NP and MP exposures, and the necessity of understanding the toxicity of various kinds of NPs to guide future research efforts.

Microplastics doi: 10.3390/microplastics3010003

Authors: Eleonora Brancaleone Daniela Mattei Valentina Fuscoletti Luca Lucentini Gabriele Favero Giancarlo Cecchini Alessandro Frugis Valentina Gioia Marco Lazzazzara

In recent years, microplastic pollution has been a hot topic as these compounds have been used in various production contexts such as health, food or technology due to their chemical and physical properties and “shelf-life,” making them almost indispensable products in daily life. On the other hand, they have a negative impact on the environment and, consequently, on biota and human health. It is therefore necessary to assess the actual presence of microplastics in drinking water by analysing real samples in order to estimate the possible exposure through drinking water consumption. In this pilot study, drinking water from different aqueous matrices was examined for the presence of microplastics and characterized in terms of shape, size, abundance and polymer type by Raman microspectroscopy analysis. Not all samples analysed were found to be contaminated with microplastics, indeed, some, as in the case of water kiosk samples, were found to be free of such contaminants. The results for the various matrices showed that the microplastics content ranged from less than 2 particles/L to a maximum of 5 + 1.5 particles/L, with sizes ranging from 30 to 100 μm and consisted of the most common polymers such as polyethylene, polypropylene or polyethylene terephthalate.

Microplastics doi: 10.3390/microplastics3010002

Authors: Thomas Senfter Andreas Walter Lukas Dür Florian Alber Manuel Berger Michael Kraxner Martin Pillei

Harmonization in the analytical framework is needed to detect, define and further categorize plastics released into the environment. In the range of particles smaller than 200 μm, hydrocyclones (HCs) have proven their capacity in removing microplastics efficiently by offering technical advantages at low operational costs. This publication aims to expand scientific knowledge by introducing four commercially available, low-priced microplastics to a pilot-scale HC setting. The physicochemical characteristics of particles as well as the separation efficiency of the test rig were investigated in depth. Particles with a density of >1000 kg/m3 passed the primary vortex and were discharged into the underflow, allowing us to employ standard mode operation. Particles with a density of <1000 kg/m3 entered the secondary vortex and were removed through the overflow. As expected, separation efficiencies were found to be higher for particles revealing a greater density difference when compared with the mobile phase water. Furthermore, an increase in the inlet volume flow revealed significant positive impacts on the separation efficiency for three plastics to a certain threshold. Data on standard and reverse mode operations presented in this publication can lay out an important source for the harmonization and standardization of future HC research, with the goal of overcoming plastic pollution by developing economically competitive separation processes.

Microplastics doi: 10.3390/microplastics3010001

Authors: Adeola Adelugba Chijioke Emenike

Microplastics (MPs) are ubiquitous and evasive in nature. They can be found in complex agricultural matrices like soil and compost. In the literature, extracting MPs from soil is more prevalent; nonetheless, the same instruments in extraction in soil samples can also be used to assess MPs in compost despite the high levels of organic material. MPs in agricultural environments have recently become a focus of research due to their status as emerging pollutants. However, the lack of standardized instruments and techniques for analysis is a major challenge in assessing MPs. Despite this limitation, this review article identified and suggested some important factors to consider when selecting suitable methods or instruments for MP analysis. This article also categorized instrumental analysis in MP studies as destructive and non-destructive and highlighted the advantages and disadvantages of methods and instruments such as visual inspection, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy (RS), and Scanning Electron Microscope (SEM). These highlights will provide researchers with a useful guide to help them choose the most appropriate method and instrumentation technique for their MP analytical research. Additionally, the article discusses the combination of two or more of these analytical instruments to improve efficiency.

Microplastics doi: 10.3390/microplastics2040031

Authors: Arely Areanely Cruz-Salas Juan Carlos Alvarez-Zeferino Jocelyn Tapia-Fuentes Sheila Liliana Dafne Lobato-Rocha Alethia Vázquez-Morillas Sara Ojeda-Benítez Samantha E. Cruz-Sotelo

Microplastics (MP) have been evidenced in marine and coastal areas worldwide, including the Gulf of California in Mexico, where the Vaquita Marina refuge area is located, which in turn borders the protected natural area Alto Golfo de California y Delta del Rio Colorado. This research aimed to determine the concentrations of microplastics in the Vaquita protection zone, analyzing samples of ten transects of surface water and samples in the sand of five beaches on the coast surrounding the Vaquita protection polygon. The total concentrations of MP in the surface water transects were from 0.000 to 0.020 MP/m3 and their most recurrent characteristics were fragments (69.0%), the chemical composition of polyethylene (60.0%), the blue color (39.0%) and a size of 2.1–3.0 mm (31.0%). While for the beaches, these corresponded to averages ranging from 28.2 ± 36.4; 17.6 to 200.7 ± 77.9; 193.7 MP/m2, the most common characteristics of MP from beaches were filaments (33.2%), PE (32.3%), white (28.0%), and a size of 4.1–5.0 mm (32.0%). The results suggest that part of the MP on the beaches and in the Vaquita Marina refuge area could come from urban areas such as the Gulf of California and activities such as fishing. It is recommended to study all the transects of the Vaquita Marina polygon and more beaches surrounding it in different seasons to better understand the status of MP pollution.

Microplastics doi: 10.3390/microplastics2040030

Authors: Serena Santonicola Michela Volgare Mariacristina Cocca Giampaolo Colavita

Despite the wide distribution of textile microfibers in the marine environment, there is still limited knowledge on microfiber ingestion in fish species intended for human consumption, mostly due to analytical issues. The present study aims to assess the occurrence of microfibers in red mullet (Mullus barbatus) samples collected from the Italian waters of the central Adriatic Sea. M. barbatus is a bottom fish that lives in contact with sediment and therefore was proposed as a sentinel species for the monitoring plastic pollution. A visual approach based on the evaluation of specific microfiber surface morphology was applied for the identification of particles of different origins. The preliminary findings showed the presence of microfibers in 80% of red mullet samples with a mean of 5.95 microfibers/individual. The majority (>80%) of the isolated microfibers were of natural/artificial origin, while the dominant colors were blue and black. The obtained results confirmed that benthic fish species are susceptible to microfiber ingestion and indicate the high availability of these particles in the Adriatic basin. Considering the spectroscopic drawbacks in microfiber analyses and the need to improve the current knowledge on the rate of contamination of fishery products, the visual approach could be a feasible, easy, and accessible method in the study of microfiber pollution, and the assessment of consumer health risks.

Microplastics doi: 10.3390/microplastics2040029

Authors: Vera I. Slaveykova Matea Marelja

The present review critically examines the advancements in the past 5 years regarding research on the bioavailability and toxicity of the nanoplastics (NPLs) to freshwater plankton. We discuss the recent progress in the understanding of adsorption, absorption, trophic transfer, and biological effects in phyto- and zooplankton induced by NPLs exposure. The influence of plankton on NPLs’ bioavailability via the excretion of biomolecules and formation of eco-corona is also examined. Despite important research developments, there are still considerable knowledge gaps with respect to NPLs’ bioavailability and trophic transfer by plankton as well as a potential adverse effect in natural aquatic systems. As plankton play a critical role in primary production, nutrient cycling, and food web structure, understanding the interactions between NPLs and plankton is essential in assessing the potential implications of NPLs pollution for aquatic ecosystem biodiversity and services.

Microplastics doi: 10.3390/microplastics2040028

Authors: Thúlio Righeti Corrêa Christine C. Gaylarde José Antônio Baptista Neto Jéssica de F. Delgado Leonardo da S. Lima Danieli L. Cunha Estefan M. da Fonseca

Environmental pollution management combined with food safety represents two of the main challenges of the last decades. Soil and water contamination has historically threatened food safety. As ubiquitous pollutants, microplastics (MPs) have attracted increasing attention over the last few years. These particles can affect the balance of terrestrial, aquatic, and aerial ecosystems. Their negative impacts are intensified when they adsorb and carry toxic chemicals. They can circulate through organisms and accumulate in human beings via food and water. Physiological dysfunctions in all species continue to be reported, both in terrestrial and aquatic ecosystems. This article considers how this might be affecting the global production of food. It reports the adverse effects induced by MPs in soils, their properties and organisms growing within and upon them, including livestock and the pollinating agents necessary for plant growth. A separate section discusses the effects of MPs on aquaculture, mentioning effects on wild species, as well as farmed fish. The growing concern of the food production sector with MPs mimics that of the world with global warming; the danger is real and requires urgent attention.

Microplastics doi: 10.3390/microplastics2040027

Authors: Kalouda Grigoriadi Merel Nooijens Ali Taşlı Max Vanhouttem Sieger Henke Luke Parker Jan Urbanus Arjen Boersma

The Microplastic Index (MPI) was presented in a previous paper as a method to assess the formation of microplastics during the application of impact and wear stresses, based on selected mechanical and physical properties of polymers. In this paper, the experimental validation of the MPI model is presented. A series of ten polymers was characterized to obtain the relevant parameters for the calculation of the MPI, i.e., the minimum particle size and volume of microplastics formed. The milling (addressing impact stress) and sanding experiments (addressing wear stress) resulted in particle sizes between 3 and 200 μm and 0.3 and 25 μm, respectively. These values were very well predicted by the MPI model, showing smaller particles for brittle polymers and larger ones for ductile polymers. In addition, the experimental-specific wear rates of impact and wear correlated well with the predicted ones, being 0.01–30 mm3/Nm for impact and 0.0002–0.012 mm3/Nm for wear. These results indicate that the MPI can be very well used to predict the tendency of a material to form microplastics. In the search for understanding and mitigating microplastic formation, the MPI can be used by both producers and end users to choose plastic grades that form fewer microplastics.

Microplastics doi: 10.3390/microplastics2040026

Authors: Michael Toni Sturm Erika Myers Anika Korzin Sabrina Polierer Dennis Schober Katrin Schuhen

The fast, affordable, and standardized detection of microplastics (MP) remains one of the biggest challenges in MP research. Comparable data are essential for appropriate risk assessments and the implementation of laws and limit values. The fluorescent staining of MP in environmental samples is a possible solution to this problem. This study investigates the optimization of a sample preparation process (hydrogen peroxide digestion) and the staining process (temperature, concentration, time, surfactants as staining aids) for using a specifically developed fluorescent dye for MP detection. The optimization is performed by comparing the sample preparation process and staining of MP from different polymers and natural particles. Further, the suitability of the optimized process for the detection of fluoropolymers and tire abrasion was tested. The results show that the optimized method (increased temperature and optimized stain concentration) can detect microplastics reliably with a total sample preparation and measurement time of 2.5–3 h per sample, reaching recovery rates of 93.3% (polypropylene) to 101.7% (polyester). Moreover, two of the three tested fluoropolymers could be detected reliably. Tire abrasion could not be detected with the here presented method, as the black color leads to strong quenching. A long-term study measuring the MP pollution in the effluent of a municipal wastewater treatment plant compared the optimized and original processes and confirmed the stability of the improved method for routine measurements and contamination control.

Microplastics doi: 10.3390/microplastics2040025

Authors: Tim Kiefer Martin Knoll Andreas Fath

This study investigates the impact different mesh-sized filtration methods have on the amount of detected microplastics in the surface water of the Danube River delta. Further, the distribution of microplastics in different size categories (20 µm, 65 µm, 105 µm) and in the water column (0 m, 3 m, 6 m) was analyzed. Our findings show that the Danube River carries 46 p∙L−1 (microplastic particles per liter) with a size larger than 105 µm, 95 p∙L−1 larger than 65 µm and 2677 p∙L−1 that are larger than 20 µm. This suggests a negative logarithmic correlation between mesh size and particle amount. The most abundant polymer throughout all samples was polyethylene terephthalate, followed by polytetrafluorethylene. Overall, the data shows that different sampling methods cannot be compared directly. Further research is needed to find correlations in particle sizes for better comparison between different sampling methods.

Microplastics doi: 10.3390/microplastics2030024

Authors: Hiroshi Asakura

Environmental pollution by microplastics (MPs) has become a growing concern, and not only professional researchers but also the citizenry are needed to understand the pollution situation and to confirm the decreasing trend of MP pollution as a result of the global reduction in plastic use. In this study, the author evaluated the accuracy of a simple method of investigating MPs on sandy beaches that can be conducted even by high school students. In a land survey using simple tools such as a tape measure and cardboard, the maximum coefficient of variation is approximately 1%. Even without heavy liquid, 89% of MPs could be recovered using only seawater. An investigation of MP content by sampling 0.5 cm of the surface layer of sand could explain more than half of the MP content when the sand was sampled to a depth of approximately 50 cm below the surface layer. A method in which the recovered MPs are not visually sorted but floating matter after boiling is considered as MPs is acceptable. If there was no concern about pumice contamination, the overestimation was approximately 1.5 times. Simple laboratory equipment such as buckets, sieves, seawater, hot plates, dryers, and electronic balances could achieve lower limits of quantification of MPs of 13 mg-MPs/m2-sand and 2 mg-MPs/kg-sand.

Microplastics doi: 10.3390/microplastics2030023

Authors: Nicolás Alejandro Sacco Fernanda Miranda Zoppas Alejandra Devard María del Pilar González Muñoz Gonzalo García Fernanda Albana Marchesini

Microplastic pollution has become a global environmental concern with detrimental effects on ecosystems and human health. Effective removal of microplastics from water sources is crucial to mitigate their impacts. Advanced oxidative processes (AOPs) have emerged as promising strategies for the degradation and elimination of microplastics. This review provides a comprehensive overview of the application of AOPs in the removal of microplastics from water. Various AOPs, such as photocatalysis, ozonation, and Fenton-like processes, have shown significant potential for microplastic degradation. These processes generate highly reactive species, such as hydroxyl radicals, which can break down microplastics into smaller fragments or even mineralize them into harmless byproducts. The efficiency of photocatalytic oxidation depends on several factors, including the choice of photocatalysts, reaction conditions, and the physicochemical properties of microplastics. Furthermore, this review discusses the challenges associated with photocatalytic oxidation, such as the need for optimization of operating parameters and the potential formation of harmful byproducts. Overall, photocatalytic oxidation offers a promising avenue for the removal of microplastics from water, contributing to the preservation of aquatic ecosystems and safeguarding human health. However, further research is needed to address the limitations and optimize the implementation of this process for effective and sustainable microplastic remediation.

Microplastics doi: 10.3390/microplastics2030022

Authors: Dahlia E. Carmona-Valdivieso Tizziana Valdivieso Víctor D. Carmona-Galindo

When plastics are discarded, they do not biodegrade and instead break down over time into progressively smaller particles, termed secondary microplastics, which adversely impact biota and human health as well as persist in the environment for centuries. Our research objective was to evaluate the capabilities of object-based image analyses in detecting compositionally varied microplastics suspended in an aquatic mesocosm under no-slip and turbulent water conditions. We found that the presence of polypropylene, polyethylene terephthalate, and low-density polyethylene microplastic pollution in both single-type and mixed-type suspensions was not detectable by either average red (R), average blue (B), average green (G), or average RBG pixel intensities, but was significantly detectable by means of total RBG pixel intensity from digital imagery of the surface-water. Our findings suggest that object-based image analyses of surface waters to quantify pixel information is better suited for monitoring the presence and absence of suspended microplastics, rather than for the stepwise determination of microplastic concentrations. We propose the development of a smartphone application to facilitate citizen-science monitoring of microplastic contamination as well as comment on future applications utilizing drone imagery to boost cloud-based mapping spatiotemporal plumes.

Microplastics doi: 10.3390/microplastics2030021

Authors: Maria Alejandra Porras-Rojas Cristina Charry-Vargas Jorge Leonardo Muñoz-Yustres Paula Martínez-Silva Luis David Gómez-Méndez

Wetlands are being contaminated by housing developments, effluents, industrial areas, and poor sanitation, resulting in the presence of plastic polymers and the development of biofilms on these materials, which represent an elevated risk to freshwater fauna and flora. The objective of this study was to characterize mesoplastics and microplastics, collected in the Gualí Wetland, Colombia, as well as to verify the presence of biofilms on such polymers. Nine water samples (36 L per sample) were evaluated at three points of the wetland; the size of the particles was determined by image analysis, the type of polymer through FTIR, and the presence of biofilms by microscopy. A total of 79 items/0.135 m3 were collected, 2 macroplastic items, 53 mesoplastic items, and 24 microplastic items. The presence of fragments (70%) and pellets (41%), with transparent (40%) and white (30%) being the predominant ones, was outstanding. Among the polymers, high-density polyethylene (HDPE) dominated, followed by expanded polystyrene. The results of SEM demonstrated the presence of diatoms on the surface of the plastic polymers. Furthermore, the results showed a greater amount of HDPE mesoplastics and microplastics in the shape of fragments and pellets. In addition, the presence of biofilms on these plastic particles can increase the adsorption of contaminants, negatively affecting this ecosystem. The outcome of this study can be used to identify bacteria that reside in biofilms associated with microplastics and mesoplastics.

Microplastics doi: 10.3390/microplastics2030020

Authors: Olga Novillo-Sanjuan Sergio Gallén Juan Antonio Raga Jesús Tomás

Microplastics’ presence in the pelagic environment is still largely unknown due to the difficulty of sampling in this part of the ocean. In this study, we quantify microplastics’ exposure in a pelagic lanternfish species from the western Mediterranean, Lampanyctus crocodilus (Risso 1810), which occupies an intermediate position in the marine food web. L. crocodilus were captured in the Ibiza Channel by a trawling vessel and microplastics were extracted by digestion of their gastrointestinal systems. Almost half of the analysed lanternfish contained microplastics, mostly blue and black fibres (40.9% and 34.66%, respectively). In fishes with at least one microplastic, the median was 3 MPs/fish (CI 95% = 3.46–6.8), similar to other studies performed in other fish species in the area. Biometric parameters of fish, such as total length and body condition, were not correlated with the number of microplastics. Data presented here contribute to quantifying the severity of microplastic pollution in the pelagic environment and in a wild, non-commercial species.

Microplastics doi: 10.3390/microplastics2030019

Authors: Clara Ivonne Ruíz-Reyes Fabiola Lango-Reynoso María del Refugio Castañeda-Chávez Angel Moran-Silva

The low cost of production and the widespread use of plastics has brought about a problem that is difficult to measure; microplastics are considered emerging pollutants because their presence can pose a risk to the environment. This study focuses on the characterization of microplastics (MPs) in the nesting area of green (Chelonia mydas) and Kemp’s ridley (Lepidochelys kempii) sea turtles, on the coastal municipalities of Nautla and Vega de Alatorre, Veracruz, Mexico. Five beaches along 15.5 km of coastline were analyzed and samples were taken in the intertidal zone. In this work, only microplastics in sizes from one to five mm were analyzed. A characterization of the potential sources of microplastics at the basin level was carried out and 94% of the samples analyzed presented MPs, the greatest amount was at site Playa Navarro (B32) (1.2 Item/kg dw), and in the high tide zone (4.86 ± 2.79 Item/kg dw). The predominant color of the MPs was white (42%), the most representative form were fragments (31%), while most of the MPs presented sizes of 4–5 mm (35%) followed by 1–2 mm (34%). The chemical composition of most of the MPs was polyethylene (55%). Regarding the sources of the MPs generation, livestock, agriculture, fishing, tourism, wastewater discharges, urban solid waste and, to a lesser extent, the plastic industry were identified. The mobilization factors of the MPs turned out to be the Colipa and Misantla rivers with runoff from the basin, wind, waves and marine currents.

Microplastics doi: 10.3390/microplastics2030018

Authors: Monika Bleszynski Edward Clark

Microplastic pollution has become an increasing danger to marine wildlife and ecosystems worldwide. The continued increase in the production of plastic products has caused microplastic pollution to become more distributed, especially along shorelines. Therefore, to better assess the pervasiveness of microplastics around the Pacific Islands, in this work, we conducted a preliminary investigation into the pervasiveness of microplastics along eight different North and South Pacific Island beaches located in New Zealand and Hawaii. Microplastic prevalence was investigated as a function of beach location, sand type, and microplastic type. Our analysis found that all eight locations contained some level of microplastics, and sheltered fine-grained sand beaches contained the highest level of microplastics, with the largest particle size distribution. In addition, spectroscopy analysis was conducted to assess the plastic type, which showed that nylon and polypropylene were the most common types of microplastics among the tested samples. The results of this study offer a preliminary insight into the microplastic accumulation among different beaches, indicating that sheltered fine-grained beaches and ecosystems may be more susceptible to microplastic accumulation.

Microplastics doi: 10.3390/microplastics2030017

Authors: Farhan R. Khan Miguel Oliveria Tony R. Walker Cristina Panti Gary Hardiman

Plastic and microplastic pollution is a complex, muti-faceted challenge that has engaged a broad alliance of stakeholder groups who are concerned with environmental, biotic and human health [...]

Microplastics doi: 10.3390/microplastics2020016

Authors: Gireeshkumar Balakrishnan Fabienne Lagarde Christophe Chassenieux Taco Nicolai

The detection and quantification of micro(nano)plastics in the marine environment are essential requirements to understand the full impacts of plastic pollution on the ecosystem and human health. Here, static light scattering (SLS) and dynamic (DLS) light scattering techniques are assessed for their capacity to detect colloidal particles with diameters between d = 0.1 and 0.8 µm at very low concentrations in seawater. The detection limit of the apparatus was determined using model monodisperse spherical polystyrene latex particles with diameters of 0.2 µm and 0.5 µm. It is shown that the concentration and size of colloids can be determined down to about 10−6 g/L. Light scattering measurements on seawater obtained from different locations in Western Europe show that colloidal particles were detected with DLS in seawater filtered through 0.8 µm pore size filters. The concentration of these particles was not higher than 1 µg/L, with an average diameter of about 0.6 µm. We stress that these particles are not necessarily plastic. No particles were detected after filtration through 0.45 µm pore size filters.

Microplastics doi: 10.3390/microplastics2020015

Authors: Yudai Ikuno Hirofumi Tsujino Yuya Haga Haruyasu Asahara Kazuma Higashisaka Yasuo Tsutsumi

Microplastics are ubiquitous in the environment, including in the ocean, soil, and air. Therefore, there are concerns regarding human exposure. Since it is known that the surface of microplastics in various environments is chemically deteriorated by external factors such as ultraviolet rays and waves, it is essential to evaluate the biological effects of degraded microplastics. In this study, we experimented by accelerating the degradation of polyethylene (PE) using vacuum ultraviolet light and prepared PE samples with different degrees of degradation. Then, we evaluated the effects of undegraded and variously degraded PE on cells using cytotoxicity tests. Based on the cytotoxicity test results, we saw a tendency for increased cytotoxicity with increasing degradation. Therefore, this study substantially links the deterioration of microplastics with their biological effects.

Microplastics doi: 10.3390/microplastics2020014

Authors: Belem Anahy Estrella-Jordan Fabiola Lango-Reynoso María del Refugio Castañeda-Chávez Jesús Montoya-Mendoza David Reynier-Valdes

Microplastic contamination has become a topic of interest and concern worldwide due to its persistence and the possible effects it may cause to the environment. When microplastics are present, they can alter their physical properties, negatively affecting the surrounding fauna, such as sea turtles that use the beaches to nest in the sand. In this study, the exposure of sea turtle nests to microplastics on the beaches of Nautla and Vega de Alatorre, Veracruz, one of the main nesting areas for the green turtle Chelonia mydas, as well as Kemp’s ridley turtle Lepidochelis kempii from the Gulf of Mexico, was determined. Sand samples were obtained directly from the nests in situ on four beaches in the area and from two nesting pens, revealing the presence of microplastics in 100% of the nests in situ, with an average abundance of 2.43 ± 2.66 #MP/kg SS and a concentration of 0.00672 ± 0.02286 mgMP/kg SS, predominantly the form of foam, white in color, and from 1 to 2 mm in size.

Microplastics doi: 10.3390/microplastics2020013

Authors: Stefania M. Manolaki Dimitra Chatzivasileiou Maria Lampa Panagiotis D. Dimitriou Aggelos Philippidis Ioannis Karakassis Nafsika Papageorgiou

Τhis study aims to measure the abundance of microplastic (MP) particles in the soft tissue of mussel (Mytilus galloprovincialis) and pearl oyster (Pinctada imbricata radiata) specimens. Samples were collected at four sites in Greece (Sagiada, Malesina, Elounda, Rhodes) from wild and farmed populations. The identification of MPs was accomplished by Raman spectroscopy. Comparisons were made between the two different species where the two species co-existed (Malesina), between the four study sites (five sampling stations) in relation to P. imbricata radiata individuals, and also in every station for the different MP types found. For the specimens from Malesina, M. galloprovincialis had more MPs in their soft tissue compared to P. imbricata radiata. Microfibers were found in abundance in M. galloprovincialis, while microfragments were found in P. imbricata radiata specimens. The main MP type found in P. imbricata radiata specimens was microfragments in all five sampling stations, and ranged between 1.54 ± 0.63 (Rhodes-baskets) and 3.56 ± 0.35 (Sagiada) MP particles/g. While the samples of mussels and pearl oysters were similar in age, the differences found in the concentrations of MPs appears to be due to their different farming methods and location characteristics concerning the five sampling stations of pearl oysters. This study indicates that the culturing system does not affect MP concentration in bivalves, and further investigation is needed to find the most appropriate method to limit and reduce MPs that end up in the farmed organisms.

Microplastics doi: 10.3390/microplastics2010012

Authors: Lyuyuan Wu Kshiti Patel Mohamad Zandieh Juewen Liu

Microplastics can adsorb and spread a variety of pollutants in the ecosystem posing a threat to human health. One of the common pollution sources of environmental waters is metal ions, which not only adsorb on microplastics but can also promote the adsorption of other invasive species such as environmental DNA. Recently, we showed that environmentally abundant metal ions (Na+, Mg2+ and Ca2+) can promote the adsorption of single-stranded DNA (ssDNA) onto microplastics. Herein, we investigated the effect of transition metal ions including Zn2+ and Mn2+ and compared them with Mg2+ for promoting DNA adsorption. To better mimic environmental DNA, we also used a salmon sperm double-stranded DNA (dsDNA) (~2000 bp). For both ssDNA and dsDNA, the transition metals induced a higher adsorption capacity compared to Mg2+, and that correlated with the higher binding affinity of transition metals to DNA. Although metal-mediated interactions were vital for ssDNA adsorption, the dsDNA adsorbed on the microplastics even in the absence of metal ions, likely due to the abundance of binding sites of the 100-times longer dsDNA. Finally, desorption studies revealed that hydrophobic interactions were responsible for dsDNA adsorption in the absence of metal ions.

Microplastics doi: 10.3390/microplastics2010011

Authors: Luca Cozzarini Joana Buoninsegni Corinne Corbau Vanni Lughi

The use of single-use or disposable plastic objects has massively increased during the last few decades, and plastic has become the main type of litter found in marine environments. The Adriatic Sea is seriously prone to marine litter pollution, and it collects about one-third of all the freshwater flowing into the Mediterranean, mainly via the river Po. This study investigated the type and composition of large microplastic debris collected in different sites in the Po Delta area. Visual classification was performed by relevant criteria, while chemical composition was assessed by infrared spectroscopy. The main plastic fraction is composed of polyolefin (76%), followed by polystyrene (19%). This proportion roughly matches global plastic production, rescaled after excluding plastics with negative buoyancy: all the identified compounds have a specific gravity lower than that of the seawater. Fragments (irregularly shaped debris) represent the most abundant category fraction (85%), followed by pellets, which represent roughly 10% of the total. Overall, the results provided an insight into large microplastic pollution in beach sediments in the Po delta area.

Microplastics doi: 10.3390/microplastics2010010

Authors: Natalja Čerkasova Kristina Enders Robin Lenz Sonja Oberbeckmann Josef Brandt Dieter Fischer Franziska Fischer Matthias Labrenz Gerald Schernewski

During recent years plastics became one of the focuses of EU policy. A harmonisation and comparability of microplastics monitoring results across Europe is needed. The complexity of microplastic data makes it necessary to develop a specific, tailor-made database rather than adapting and modifying one of the existing databases. To meet this demand, we present a publicly accessible, flexible, and extendable structured relational database for particle-based microplastic data. The developed relational database is adaptive and meets the specific demands of microplastics, e.g., a large variety of sampling, processing and analytical methods, many types of plastics, and a very wide size spectrum ranging from micrometres to millimetres. In this paper we discuss the development of the database, data entry specifics, sample analysis methods, microplastics data manipulation and quality assurance, and database integration and accessibility.

Microplastics doi: 10.3390/microplastics2010009

Authors: Antonio Pellegrino Denise Danne Christoph Weigel Harald Seitz

In today’s age, plastic waste is a major problem for our environment. The decomposition of plastic waste causes widespread contamination in all types of ecosystems worldwide. Micro-plastics in the lower micrometer size range and especially nano-plastics can become internalized by cells and thus become a threat to human health. To investigate the effects of internalized micro- and nano-plastics on human gene transcription, we used an in vitro assay to quantify CREB (cAMP response element binding protein) mediated transcription. Here we show that CREB mediated gene expression was mainly but not exclusively induced by phosphorylation. In addition, the amount of CREB affected transcription was also studied. We were also able to show that the strong CREB mediated stimulation of transcription was diminished by micro- and nano-plastics in any chosen setting. This indicates a threat to human health via the deregulation of transcription induced by internalized micro- and nano-plastics. However, this established quantifiable in vitro transcription test system could help to screen for toxic substances and non-toxic alternatives.

Microplastics doi: 10.3390/microplastics2010008

Authors: Monika Rani Serena Ducoli Stefania Federici Laura Eleonora Depero

The abundance of microplastics in the environment poses a constant threat to all parts of the ecosystem, and the scientific community is called upon to help solve the problem. Numerous studies have been published for microplastic analysis, especially in the last decade, with vibrational spectroscopy being the preferred method. According to recent literature, portable spectrometers operating in the near-infrared (NIR) range are being used for the analysis of different types of polymers, and this technique has recently found its way into the analysis of microplastics as a good alternative to expensive and complicated benchtop instruments, such as Fourier-transform infrared (FTIR) spectrometers. The aim of this study is to investigate and evaluate research trends, leading publications, authors, countries, and limitations of the use of NIR spectroscopy in microplastics research, with a comparison to the established FTIR technique.

Microplastics doi: 10.3390/microplastics2010007

Authors: Lauriane Ledieu Ngoc-Nam Phuong Bernard Flahaut Pauline Radigois Julya Papin Cécile Le Guern Batrice Béchet Johnny Gasperi

Municipal landfills receive a high amount of plastic waste and due to the occurring physical and biochemical degradation processes, could be significant sources of microplastics (MP). Evaluating the threat to groundwater through the transfer of MP via landfill leachates require more research. The former “Prairie de Mauves” landfill, operated from 1963 to 1987 by the municipality of Nantes (France), and located above the alluvial groundwater of the Loire River, represents a good candidate for such investigations. Leachates and groundwater were sampled along a transect line from upstream to downstream of the landfill, in March and June 2022. MP (>25 µm) were quantified and characterized using µFTIR imaging in transmission mode. MP were observed in every sample with concentrations ranging from 0.71 to 106.7 MP/L. Concentrations in the leachates and the alluvial groundwater illustrate a migration of MP. Twelve polymers were identified and polyethylene (PE) and polypropylene (PP) were predominant. After a conventional rainfall event (14.3 mm), higher concentrations, diversity, and size ranges of MP were observed. Water infiltration through the heterogeneous geological substratum therefore enhanced the migration of larger MP towards the alluvial groundwater of the Loire River.

Microplastics doi: 10.3390/microplastics2010006

Authors: Gaston Casillas Brian Charles Hubbard Jana Telfer Max Zarate-Bermudez Custodio Muianga Gregory M. Zarus Yulia Carroll April Ellis Candis M. Hunter

Scientific studies of microplastics have expanded since 2015, propelling the topic to the forefront of scientific inquiry. Microplastics are ubiquitous in the environment and pose a potential risk to human health. The purpose of this review is to organize microplastics literature into areas of scientific research, summarize the state of the literature and identify the current data gaps in knowledge to promote a better understanding of human exposure to microplastics and their potential health effects. We searched for published literature from eight databases. Our search focused on three categories: (1) microplastics in the environment, (2) adsorption and absorption of chemicals to microplastics, and (3) human exposure to microplastics in the environment. We screened all abstracts to select articles that focused on microplastics. We then screened the remaining articles using criteria outlined in a questionnaire to identify and assign articles to the three scoping review categories. After screening abstracts, we selected 1186 articles (19%) to thoroughly assess their appropriateness for inclusion in the final review. Of the 1186 articles, 903 (76.1%) belonged to the environmental category, 268 (22.6%) to the adsorption and absorption category, and 16 (1.3%) to the human exposure category. Water was the most frequently studied environmental medium (440 articles). Our assessment resulted in 572 articles selected for the final review. Of the 572 publications, 268 (48.2%) included a geographic component and 110 (19.2%) were the product of literature reviews. We also show that relatively few publications have investigated human health effects associated with exposures to microplastics.

Microplastics doi: 10.3390/microplastics2010005

Authors: Marcelo Pompermayer de Almeida Christine Gaylarde Fabiana Cunha Pompermayer Leonardo da Silva Lima Jessica de Freitas Delgado Danniela Scott Charles Vieira Neves Khauê Silva Vieira José Antônio Baptista Neto Estefan Monteiro Fonseca

Microplastic pollution in aquatic ecosystems has drawn attention not only because microplastics are likely to accumulate anywhere but also because they cause negative impacts both to aquatic biota and, indirectly, to public health, as a result of their presence. The understanding of the distribution and accumulation patterns of this “new contaminant” is fundamental for the calibration of environmental risk studies. However, research on its migration pattern and consequent distribution is still limited. The present study has focused on the peculiar physical characteristics of plastic microparticles and the response to environmental factors such as hydrodynamics and physical chemistry of water on the diffusion dynamics of these pollutant agents. Therefore, we examined information about the vertical abundance distribution, the composition, and the sizes of microplastics, along with the varied aquatic environments existing on Earth. This study provides valuable evidence for the accumulation trend of microplastics across the environment and the peculiar particle characteristics that dictate their distribution patterns. The present study concluded that detailed studies should be carried out in order to add information about the behavior of plastic microparticles in aquatic environments and thus subsidize the calibration of existing information, thus increasing its accuracy in understanding the diffusion patterns of these polluting agents.

Microplastics doi: 10.3390/microplastics2010004

Authors: Microplastics Editorial Office Microplastics Editorial Office

High-quality academic publishing is built on rigorous peer review [...]

Microplastics doi: 10.3390/microplastics2010003

Authors: Madalina Andreea Badea Mihaela Balas Anca Dinischiotu

Microplastics (MPs) represent small plastic particles with sizes between 1 μm and 5 mm, are insoluble in water, andclassified as primary (these are originally produced in small sizes) or secondary (the result of the degradation of plastic) types. MPs accumulate in all ecosystems, including freshwater environments, where they are subjected to degradation processes. Due to their ubiquitous nature, freshwater ecosystems, which have a vital importance in human life, are permanently subjected to these small plastic particles. In this context, MPs pollution is considered to be a global issue, and it is associated with toxic effects on all the elements of the freshwater environment. In this review, we present, in detail, the main physical (density, size, color, shape, and crystallinity) and chemical (chemical composition and modification of the MPs’ surface) properties of MPs, the mechanism of biodegradation, and the consequences of autotrophic organisms and fauna exposure by focusing on the freshwater environment. The toxicity mechanisms triggered by MPs are related to the critical parameters of the particles: size, concentration, type, and form, but they are also dependent on species exposed to MPs and the exposure route.

Microplastics doi: 10.3390/microplastics2010002

Authors: Melek Isinibilir Kamil Mert Eryalçın Ahmet Erkan Kideys

Microplastic pollution is a problem not only in the marine environment but also in freshwater ecosystems. Water flea (Daphnia magna) is one of the most common omnivorous cladocerans in freshwater ecosystems. In this study, the potential effects of microplastics (fluorescent polystyrene beads with dimensions of 6 microns) on the survival, growth and reproduction of Daphnia magna were examined during 21 days of laboratory experiments. Microplastics (MPs) were observed to be ingested alone or along with either the microalgae Chlorella vulgaris (Cv) or baker’s yeast (By). D. magna fed exclusively with microplastics showed a drastic decline in survival similar to that in the starving group. The least growth in total length or width was observed in Daphnia specimens fed only MPs and the starved groups. Daphia fed with a mixture of MPs/Cv or MPs/By produced a significantly (p < 0.05) lower number of ephippia. Our results show that high concentrations of microplastics adversely affect Daphnia magna populations.

Microplastics doi: 10.3390/microplastics2010001

Authors: Davi R. Munhoz Paula Harkes Nicolas Beriot Joana Larreta Oihane C. Basurko

Although (micro)plastic contamination is a worldwide concern, most scientific literature only restates that issue rather than presenting strategies to cope with it. This critical review assembles the current knowledge on policies and responses to tackle plastic pollution, including peer-reviewed scientific literature, gray literature and relevant reports to provide: (1) a timeline of policies directly or indirectly addressing microplastics; (2) the most up-to-date upstream responses to prevent microplastics pollution, such as circular economy, behavioral change, development of bio-based polymers and market-based instruments as well as source-specific strategies, focusing on the clothing industry, tire and road wear particles, antifouling paints and recreational activities; (3) a set of downstream responses tackling microplastics, such as waste to energy, degradation, water treatment plants and litter clean-up strategies; and examples of (4) multifaceted responses focused on both mitigating and preventing microplastics pollution, e.g., approaches implemented in fisheries and aquaculture facilities. Preventive strategies and multifaceted responses are postulated as pivotal to handling the exacerbated release of microplastics in the environment, while downstream responses stand out as auxiliary strategies to the chief upstream responses. The information gathered here bridges the knowledge gaps on (micro)plastic pollution by providing a synthesized baseline material for further studies addressing this environmental issue.

Microplastics doi: 10.3390/microplastics1040045

Authors: Rebecca Talbot Maritza Cárdenas-Calle James M Mair Franklin López Guillermo Cárdenas Beatríz Pernía Mark G. J. Hartl Miguel Uyaguari

The composition, abundance and distribution of macroplastics (MAPs) and microplastics (MPs) in the Vinces and Los Tintos rivers were determined in three sites (Pueblo Nuevo, Santa Marianita, Los Tintos) from the low basin in the coastal province of Guayas, Ecuador. MAPS were recorded by visual census, covering a total distance of 140 m, and MPs were extracted in the intertidal sediments via density separation using a saturated NaCl solution, and these were counted using a stereomicroscope. A total of 940 plastic items were identified. The predominant debris was plastic with 85.2%, followed by manufactured materials and metals. The Vinces River contained the highest abundance of plastic in the locality of Pueblo Nuevo. The most abundant plastic was MPs. The most common MAPs were plastic bags (23%), food packaging (17%) and foamed plastic (8%). MP size classes quantified between 0.15 and 2.52 mm in intertidal, very fine sandy sediment and decreased in abundance with increasing grain size. The most common MPs were fibres (65.2%) (black (43.8%) and blue (25.8%)), and their distribution has a high correlation with population density and water flow direction: Santa Marianita 5.55 g−1, Pueblo Nuevo 7.39 g−1, Los Tintos 8.17−1. A significant abundance of fibres was identified in Pueblo Nuevo. The plastic spatial distribution revealed major plastic pollution in areas where recreational and tourism activities have been developed. Therefore, we recommend implementing awareness campaigns by educating businesses, residents and tourists on managing solid waste (especially plastic) and wastewater. Our results can serve as a baseline for future plastic monitoring in the area.

Microplastics doi: 10.3390/microplastics1040044

Authors: Daniele Calore Nicola Fraticelli

Microplastics make up a significant amount of the overall quantity of plastic debris that is present in seawater. However, their detection and monitoring at sea is cost-inefficient and challenging; typically, it consists of water sampling with special manta nets, followed by long (i.e., weeks) laboratory analysis to obtain valid results. The analysis of the state-of-the-art technologies capable of monitoring/detecting microplastics in the sea (typically in coastal areas) presented in this paper shows that there are currently no specific tools to obtain quick measurements. The classic multiparametric probes are useless and the contribution of their relative chemical–physical parameters to determine the presence of microplastics in water is insignificant. The evolution in the last decade of hardware and software tools for capturing hologram images and related post-processing seems to be one of the most effective methods available currently for the rapid detection of microplastics in seawater. In particular, some results of monitoring campaigns carried out in the Adriatic Sea using this type of technology are reported. The acquired data are analyzed and discussed, highlighting their strengths and weaknesses, with indications of the possible methodologies that could be used to improve these systems.

Microplastics doi: 10.3390/microplastics1040043

Authors: Judith S. Weis Francesca De Falco

Microplastics have become a topic of considerable concern and intensive study over the past decade. They have been found everywhere in the oceans, including the deepest trenches and remotest parts of the Arctic. They are ingested by many animals and some are incorporated into tissues. There is considerable effort in studying what effects they have on marine life. It has become clear that when water samples are collected in ways that prevent most long thin particles from escaping through pores of a net, the most abundant type of microplastics found in water and sediments are microfibers (fibers with dimensions less than 5 mm). The major source of these pollutants is synthetic textiles, such as polyester or polyamides, which shed microfibers during their entire life cycle. Microfibers are released during textile manufacturing, everyday activities (e.g., washing, drying, wearing) and final disposal. The complexity of microfiber release mechanisms and of the factors involved make the identification and application of ways to reduce the inputs of microfibers very challenging. A comprehensive approach is strongly needed, taking into account solutions at a number of levels, such as re-engineering textiles to minimize shedding, applying washing machine filters, developing advanced wastewater treatment plants and improving the management of textile wastes. To harmonize and make mandatory the solutions identified, a variety of potential government policies and regulations is also needed.

Microplastics doi: 10.3390/microplastics1040042

Authors: Collin J. Weber Moritz Bigalke

After five years of research on microplastic pollution of soils it becomes obvious that soil systems act as a reservoir for microplastics on global scales. Nevertheless, the exact role of soils within global microplastic cycles, plastic fluxes within soils and environmental consequences are so far only partly understood. Against the background of a global environmental plastic pollution, the spatial reference, spatial levels, sampling approaches and documentation practices of soil context data becomes important. Within this review, we therefore evaluate the availability of spatial MP soil data on a global scale through the application of a questionnaire applied to 35 case studies on microplastics in soils published since 2016. We found that the global database on microplastics in soils is mainly limited to agricultural used topsoils in Central Europe and China. Data on major global areas and soil regions are missing, leading to a limited understanding of soils plastic pollution. Furthermore, we found that open data handling, geospatial data and documentation of basic soil information are underrepresented, which hinders further understanding of global plastic fluxes in soils. Out of this context, we give recommendations for spatial reference and soil context data collection, access and combination with soil microplastic data, to work towards a global and free soil microplastic data hub.

Microplastics doi: 10.3390/microplastics1040041

Authors: Rawa Ahmed Mahmood Niyazi Ugur Kockal

Investigations on the usability of waste plastics as a new generation of construction materials have become one of the main concerns of researchers and engineers in recent decades. Waste plastics can be used either as aggregate replacement or as fiber reinforcement to enhance the properties of cementitious mixtures. This study focuses on the properties of waste PVC fiber-reinforced mortars containing silica fume and micro silica. Plastic fibers were added to the mortar mixes by volume fractions of 0%, 1%, 2%, and 3%. Cement was replaced by micro silica and silica fume by 5%, 10%, and 15% by weight of cement, respectively. In total, 28 different groups of mortars were produced. The results showed an enhanced ductility and deformation behavior of mortars upon the addition of waste PVC plastic fibers. It can be seen that fibers restricted crack propagation and maintained integrity, hence improving the ductility of the mortars. On the other hand, the addition of fibers led to a reduction in the physical and mechanical properties of the mortar samples. The compressive strength of the mortar samples decreased gradually by increasing the fiber content. Cement replacement by silica fume improved mechanical and microstructural properties of the mortars. The results also demonstrated that silica fume significantly decreased the porosity and water absorption capacity of mortar samples.

Microplastics doi: 10.3390/microplastics1040040

Authors: Sinem Hazal Akyildiz Rossana Bellopede Hande Sezgin Ipek Yalcin-Enis Bahattin Yalcin Silvia Fiore

Textile wastewater is polluted by inorganic/organic substances, polymers, dyes, and microfibers (MFs), which are microplastics (MPs) and natural fibers. This work is aimed at the preliminary investigation of MFs and MPs in textile industrial wastewater, and at evaluating the removal efficiency of an on-site wastewater treatment plant (WWTP). Ten samples of inflows and outflows of the WWTP of a textile company (applying a physic-chemical process) have been analyzed. Firstly, the samples underwent a pretreatment with 15% hydrogen peroxide at 25 °C for 5 days to remove organic compounds. Secondly, the MFs were recovered from the aqueous phase by pre-screening centrifugation, density separation, and filtration as alternative options. Filtration obtained the best performances, compared to the other recovery processes. Thirdly, the MFs were counted through optical microscopy and the MPs were identified through micro-FTIR. The MFs amount in the inflow samples was in the range of 893–4452 MFs/L. The outflow samples (310–2404 MFs/L) exhibited a 38–65% reduction compared to the inflows, demonstrating that up to 62% of residual MFs can enter the sewer network or the receiving water body. Cotton and wool, and numerous MPs (acrylic, polyester, polypropylene, polyamide, and viscose/rayon) were identified in the inflow and outflow samples (with the only exception of “dense” viscose (rayon), not detected in the outflows, and probably retained by the WWTP with the sludge). This study, even if just preliminary, offers interesting hints for future research on MFs/MPs detection in textile wastewater, and on the performance of a full-scale WWT process for their removal.

Microplastics doi: 10.3390/microplastics1030039

Authors: Leonardo Lopes Costa Lucia Fanini Mohamed Ben-Haddad Maurizio Pinna Ilana Rosental Zalmon

In order to identify how research contributes to the knowledge of marine litter as a pressure on beaches, we reviewed interactions of beach fauna with this pollutant. Entanglement of pinnipeds in fishing gear, negative correlations between macroinvertebrates abundance and sediment pollution, and the presence of plastic surrounding burrows were primary evidence of beach fauna interacting with stranded litter. Ingestion represents the main body of research; microplastic uptake by invertebrates has been studied by laboratory experiments and field collections to report the presence of polymers in tissues. In the natural context, the higher the urbanization surrounding beaches and sediment pollution, the higher the concentration of microplastics in organs of bivalves. This approach currently constitutes the main research direction, but ecotoxicological assays are emerging prospects to assess the effects of exposure to microplastics. Beached macroplastics entangle and entrap invertebrates and vertebrates, and studies have reported increasing negative interactions with seals and sea turtles. Changes in nesting and feeding behavior of resident and transient organisms have been shown as typical early warning indicators of marine litter impacts. The focus on fauna–litter interactions holds terrific potential for research and citizen science projects, which finally becomes a powerful driver towards environmental awareness on sandy beaches.

Microplastics doi: 10.3390/microplastics1030038

Authors: Vo Khuyen Dinh Le Hung Le Axel Fischer Christina Dornack

Plastic pollution is one of the significant environmental concerns due to the threefold increase in global plastic waste. Marine microplastics, including petroleum-based plastic pieces and synthetic and artificial fibers smaller than 5 mm, are not only ubiquitous in natural water but also high in wastewater streams due to the direct discharge, transfer and breakdown of plastic items. This research aims to investigate the presence and dispersion of microplastics in the downtown area and coastal suburban area of Ho-Chi-Minh City by using Raman microscopy. As a result, the most common plastics (PE, PET, PA, PP, PVC, PS and PMMA) were detected, and most of them were fibrous shorter than 500 μm. The total microplastics decreased gradually from the urban waterborne (up to 220 MPs/L) via Can Gio UNESCO Mangrove Biosphere Reserve (10 MPs/L) and to the East Sea (3 MPs/L), which reveals the potential role of the mangrove in reducing marine contaminants including microplastics. This study provides important insights into microplastic pollution in the Western Pacific Region, especially the Saigon-Dong Nai river systems, supporting useful data for natural water resources management.

Microplastics doi: 10.3390/microplastics1030037

Authors: Maris Klavins Linards Klavins Olena Stabnikova Viktor Stabnikov Andrii Marynin Linda Ansone-Bertina Marcis Mezulis Ashok Vaseashta

A large amount of the globally produced plastics are not treated and are eventually released into landfills or natural environments, including surface waters. The plastics that enter the aquatic environment are very often microplastics, which are produced in households by the slow degradation or abrasion of plastic products, or as whole plastic products, which eventually degrade (abrasion, photodegradation). Together with microplastics, other pollutants such as pharmaceuticals of various kinds enter surface waters—both of these counterparts can interact with each other as well as with organic and inorganic molecules available in the natural environment. The aim of this study was to identify the interaction of microplastics with pharmaceuticals, especially under conditions that are common in inland waters as well as the seas and oceans that the rivers feed their water into. It was found that salinity has a great impact on the sorption capacity of microplastics and pharmaceuticals. The sorption of naturally occurring humic substances (humic and fulvic acids) can greatly increase when the microplastic–pharmaceutical complex is formed; however, the priority of the interaction happens with pharmaceuticals and humic substances. Such complexes can influence the organisms that feed on small organic-matter particles, as they can be mistaken for food and thus be transferred throughout the food chain.

Microplastics doi: 10.3390/microplastics1030036

Authors: Stefanie Krais Nils Anthes Sven Huppertsberg Thomas P. Knepper Katharina Peschke Aki S. Ruhl Hannah Schmieg Tabea Schwarz Heinz-R. Köhler Rita Triebskorn

As there is still little knowledge of interactions between microplastics (MP) and hydrophilic compounds, we propose ways the toxicity of hydrophilic pesticides can be modulated by MP, when sorption can be excluded. Larvae of Chironomus riparius were exposed to thiacloprid (TH, 1 µg/L) and polystyrene microplastic particles (PS; <50 µm; 150,000 and 1,000,000 particles/L) for 96 h, solely or in co-exposure. Burrowing behavior and mortality were observed. Larvae in treatments containing PS established themselves quicker in the sediment and kept the ability to rebury for a longer time compared to control and TH, respectively. While TH elevated the mortality, exposure to PS alone did not affect the survival of the larvae. In co-exposure of TH and PS, a concentration of 150,000 particles/L significantly reduced the toxicity of 1 µg/L TH after 96 h, an effect that was not observed at 1,000,000 particles/L. Therefore, we hypothesize that this modulation of the toxicity of TH eventually may have resulted from a combination of a ‘protective MP layer’ in the gut and a higher retention time of particles in larvae exposed to 150,000 particles/L than in those exposed to 1,000,000 particles/L due to the lower number of ingestible particles in the former.

Microplastics doi: 10.3390/microplastics1030035

Authors: Tanja Pušić Branka Vojnović Mirjana Čurlin Ivica Bekavac Tea Kaurin Katia Grgić Kristina Šimić Zorana Kovačević

Textile materials from polyester fibres are sensitive to washing, especially at higher temperatures, due to their thermoplastic properties, hydrophobic nature and sensitivity to the alkaline medium. The issue of microplastic fibres’ (MFs’) release from polyester textiles is a topic that attracts the attention of researchers from different scientific fields, since microplastics are now among the serious environmental risks. In this study, two washing protocols, a standard and an innovative procedure, were presented, aiming to preserve the properties of polyester fabrics and reduce the pollution of washing effluents. The standard procedure followed HRN EN ISO 6330, while the innovative procedure was a modification of the standard that involved gradually cooling the bath before rinsing. The effects of these washing protocols were studied based on the physicochemical properties of the fabrics compared to the unwashed material, the composition of the effluents, and the filtrates after 10 cycles. The characterisation parameters of the fabrics, effluents and filtrates according to the standard and the innovative washing protocols showed differences in the observed parameters during the 10 washing cycles. The obtained results show the usefulness of the proposed concept of cooling the bath before rinsing in order to preserve the properties of polyester fabrics and reduce the load of washing effluents. Hierarchical cluster analysis (HCA) also confirmed differences in pH, conductivity and turbidity for effluents and filtrates from standard and innovative washing protocols.

Microplastics doi: 10.3390/microplastics1030034

Authors: Valeria Jimenez-Cárdenas Andrea Luna-Acosta Luis David Gómez-Méndez

This study aims to determine whether differences exist between the presence of microplastics and mesoplastics in fishes of coral reef and mangrove ecosystems, in Isla Grande, Colombian Caribbean. The collection of three species of coral reef (Centropomus undecimalis, Caranx hippos, and Lutjanus synagris) and three species of mangrove from coral reef (Centropomus undecimalis, Eugerres plumieri, and Archosargus rhomboidalis) were found to have ingested microplastics and mesoplastics, with a significantly higher in the mangrove species than in the coral reef species (1.9 vs. 1.6 items/individual). Furthermore, the average abundance and weight of microplastics and mesoplastics were significantly higher in females than in males (p < 0.05) and the abundance of microplastics and mesoplastics in the intestines was significantly higher than in the stomach (p < 0.05). PE, polyester, PVC, and PET were the most abundant polymers among common plastics found in species of the two habitats. Our findings highlight the importance of more rigorous plastic waste management strategies in areas nearby the coast and mangrove habitats.

Microplastics doi: 10.3390/microplastics1030033

Authors: Wihann Conradie Christie Dorfling Annie Chimphango Andy M. Booth Lisbet Sørensen Guven Akdogan

A wide range of weathering processes contributes to the degradation of plastic litter items which leads to the formation of microplastics that may be detrimental to marine ecosystems and the organisms inhabiting them. In this study, the impact of UV exposure on the degradation of clear polypropylene (CPP), black polypropylene (BPP), and polyethylene terephthalate (PET) packaging materials was investigated over a period of 6 weeks under dry air conditions representing the terrestrial environment. The exposure was conducted using differently sized and shaped samples at irradiation intensities of 65 W/m2 and 130 W/m2. Results indicated that UV irradiation led to changes in the properties of PET, BPP, and CPP that were proportional to the intensity delivered, leading to a higher level of mass loss, carbonyl indices, crystallinities, and microhardness in all polymer types at 130 W/m2 relative to 65 W/m2. However, material shape and size did not have a significant influence on any property for any of the test materials. Increased mass loss over time was accompanied by considerable increases in carbonyl index (CI) for both PPs. Clear PP (CPP) underwent the most severe degradation, resulting in the highest mass loss, increase in crystallinity, and CI. BPP was less degraded and modified by the UV irradiation than the CPP, indicating that the colorant, carbon black, provided some degree of protection to the bulk polymer material. PET was the least degraded of the three materials, suggesting this polymer type is more resistant to UV degradation. The differences in the degradation behaviours of the three test materials under dry environmental conditions indicate that the UV exposure history of plastic litter might play an important role in its potential for further degradation once it reaches the marine environment. Furthermore, analysis of samples exposed to UV in aqueous media reveals a more irregular set of trends for most material properties measured. Overall, the degree of degradation resulting from UV irradiation in dry environments was more pronounced than in aqueous environments, although the most significant property changes were observed for materials without previous UV exposure histories. Samples with previous UV histories showed higher resistance to further crystallinity changes, which appeared to be due to crosslinking in the pretreatment exposures inhibiting chain alignment into crystalline structures. The effect of solution medium was insignificant, although the presence of water allowed hydrolytic degradation to proceed simultaneously with UV degradation for PET. The reduction of CI in pretreated materials in the aqueous exposures, combined with the mass loss, suggest that the degraded surface layer erodes or products dissolve into surrounding solution medium, leaving a fresh surface of plastic exposed.

Microplastics doi: 10.3390/microplastics1030032

Authors: Manuela Piccardo Gabriele Salvatore Priami Serena Anselmi Stanislao Bevilacqua Monia Renzi

An intra-laboratory calibration to quantify microplastic in fine-grained marine sediments was performed with two objectives: (a) to determine the recovery rate of self-produced microplastics characterized by a size ranging from 220 µm to 5 mm and differing in color (pink, orange, gray, yellow, silver), shape (fragments, filaments, spheres, films), and chemical composition (polystyrene, polyethylene, polyvinyl chloride, acrylonitrile-butadiene-styrene, polypropylene, poly(methyl methacrylate)) artificially introduced into real samples; and (b) to analyze whether operator experience can be a key factor in the quality of the results. To answer this question, the same protocol was assigned to an experienced and an inexperienced operator. The results of this comparison are detailed in terms of root mean square and percent error. Possible strategies to increase the recovery rate are presented, and an ad hoc category, namely “glitter”, was created to adjust the results with respect to this unique type of microplastic usually ignored and excluded from the analysis.

Microplastics doi: 10.3390/microplastics1030031

Authors: Klytaimnistra Katsara George Kenanakis Eleftherios Alissandrakis Vassilis M. Papadakis

Food packaging has been demonstrated as a crucial issue for the migration of microplastics (MPs) into foodstuffs, concerning human health risk factors. Polymeric materials called plastics are continuously utilized in food packaging. Polyethylene (PE) is commonly used as a food packaging material, because it offers easy handling during transportation and optimal storage conditions for food preservation. In this work, three types of cured meat products of different fat compositions and meat processing methods—bacon, mortadella, and salami—were studied using spectroscopic methods (Raman and FT–IR/ATR) to determine the migration of low-density polyethylene (LDPE) from plastic packaging to the surface of the meat samples. The experimental duration of this study was set to be 28 days owing to the selected meat samples’ degradation, which started to become visible to the human eye after 10 days of storage in vacuum LDPE packaging, under refrigerated conditions at 4 °C. Spectroscopic measurements were performed at 0, 3, 9, 12, 15, and 28 days of storage to obtain comparative results. We demonstrated that the Raman spectral peaks of LDPE firstly appeared as a result of polymeric migration on day 9 in Bacon, on day 15 in Salami, and finally on day 28 in Mortadella. On day 28, all meat samples were tainted, with a layer of bacterial outgrowth developed, as proven by bright–field microscopic observation. Food packaging migration to the surface of cured meat samples was validated using Raman vibrational spectroscopy. To ensure minimal consumption of MPs in cured meat products stored in plastic packaging, while at the same time maintaining good food quality, they should be kept in refrigerated conditions and consumed within a short period of time. In this work, the migration of MPs from food packaging to the surface of cured meat samples was observed using micro-Raman spectroscopy.

Microplastics doi: 10.3390/microplastics1030030

Authors: Klytaimnistra Katsara George Kenanakis Eleftherios Alissandrakis Vassilis Papadakis

In ancient Greece, people said that “honey is the Food of the Gods”, and they were right. They believed that honey fell from the sky, with the morning dew, on the flowers and leaves, and from this point, the bees collected it. Honey is one of the most nutritious food products, which can be found in most homes. A lot of honey products are stored in different types of packaging materials, including plastics. Plastic packaging has been studied for the migration of plasticizers, chemical compounds, and MPs and NPs in foodstuffs. Most of them have been achieved through food simulations, while some studies managed to detect and isolate MPs/NPs. Recent studies presented evidence for the presence of MPs/NPs in honey products but not directly connected to food packaging or to the different types of honey and their properties (viscosity, pH value, and moisture content) or their storing conditions (temperature, humidity, light, and time). Spectroscopic and analytical techniques like Raman, FTIR, HPLC, and GC-MS are in the foreground for MP/NP detection and identification, but a universal way of isolation, detection, characterization, and quantification has not yet been found. This leaves an open field for more work to be done to clarify the factors affecting the migration of plastic packaging material in honey.

Microplastics doi: 10.3390/microplastics1030029

Authors: Beatrice Malchiodi Erika Iveth Cedillo-González Cristina Siligardi Paolo Pozzi

Microplastic (MP) contamination is an urgent environmental issue to address. Fibrous microplastics (FMPs) are the principal MP type in the air and have already been found in human stool and lung tissues. FMPs are generated from the lifecycle of synthetic and blended textiles and are expected to increase due to fast fashion. Among textile processes, the finishing of fabrics is estimated to generate 5000 t/year of textile waste fibers in Italy, including FMPs. To limit FMPs spread, this paper suggests, for the first time, the direct collection of blended finishing textile waste microfibers and reuse in designing thermal-insulating and mechanical-performing fiber-reinforced cementitious composites (FRCs). The microfibers were thoroughly characterized (size, morphology, composition, and density), and their use in FRCs was additionally evaluated by considering water absorption and release capacity. Untreated, water-saturated, and NaOH-treated microfibers were considered in FRCs up to 4 wt%. Up to a +320% maximum bending load, +715% toughness, −80% linear shrinkage, and double-insulating power of Portland cement were observed by increasing microfiber contents. NaOH-treated and water-saturated microfibers better enhanced toughness and linear shrinkage reduction. Therefore, green and performant composite construction materials were obtained, allowing for the mitigation of more than 4 kg FMPs per ton of cement paste. This is a great result considering the FMP contamination (i.e., 2–8 kg/day fallout in Paris), and that FRCs are promising and shortly-widely used construction materials.

Microplastics doi: 10.3390/microplastics1030028

Authors: Georgia Chatziparaskeva Iliana Papamichael Irene Voukkali Pantelitsa Loizia Georgia Sourkouni Christos Argirusis Antonis A. Zorpas

Composite materials constitute an appealing choice in many industrial sectors, due to their unique composition and characteristics, such as low maintenance requirements, light weight, corrosion resistance, and durability. However, the sustainable management of end-of-life composite materials remains a challenge. Recovery strategies, design aspects, and their interconnection are currently largely unexplored, while technologies involved in the circular economy (reuse, reduce, recycle, refurbish, etc.) could be improved. The current paper provides an overview of the existing methods of composite material waste management, while presenting new circular economy prospects for end-of-life strategies and providing a brief roadmap towards circularity for industries. Finally, existing circular economy practices in regard to composites are presented in different European countries to present the applicability of composite material end-of-life waste management.

Microplastics doi: 10.3390/microplastics1030027

Authors: Jana Weisser Teresa Pohl Natalia P. Ivleva Thomas F. Hofmann Karl Glas

Assessing data analysis routines (DARs) for microplastics (MP) identification in Fourier-transform infrared (FTIR) images left the question ‘Do we overlook any MP particles in our sample?’ widely unanswered. Here, a reference image of microplastics, RefIMP, is presented to answer this question. RefIMP contains over 1200 MP and non-MP particles that serve as a ground truth that a DAR’s result can be compared to. Together with our MatLab® script for MP validation, MPVal, DARs can be evaluated on a particle level instead of isolated spectra. This prevents over-optimistic performance expectations, as testing of three hypotheses illustrates: (I) excessive background masking can cause overlooking of particles, (II) random decision forest models benefit from high-diversity training data, (III) among the model hyperparameters, the classification threshold influences the performance most. A minimum of 7.99% overlooked particles was achieved, most of which were polyethylene and varnish-like. Cellulose was the class most susceptible to over-segmentation. Most false assignments were attributed to confusion of polylactic acid for polymethyl methacrylate and of polypropylene for polyethylene. Moreover, a set of over 9000 transmission FTIR spectra is provided with this work, that can be used to set up DARs or as standard test set.

Microplastics doi: 10.3390/microplastics1030026

Authors: Juan A. Conesa

The presence of microplastics (MPs) in the environment, and the effects that the ingestion of these materials can have on organisms, can be aggravated by the adsorption of harmful substances on the surface or inside the MPs. Of special relevance are the studies that have been carried out on the adsorption and transport of polycyclic aromatic hydrocarbons (PAHs) as well as persistent organic pollutants (POPs) such as dioxins and furans (PCDD/Fs). This review will delve into the research carried out to date regarding the adsorption by conventional and biodegradable MPs of dangerous organic compounds such as those mentioned. In general, the presence of MPs is considered a vector for the entry of these contaminants into living beings, since their capacity to adsorb contaminants is very high and they are ingested by different organisms that introduce these contaminants into the trophic chain.

Microplastics doi: 10.3390/microplastics1030025

Authors: John J. Mbugani John F. Machiwa Daniel A. Shilla Dativa Joseph Wahabu H. Kimaro Farhan R. Khan

Microplastics-induced histopathological changes in gastrointestinal tracts of fish have been widely reported. However, the translation of adverse effects in the gut to impacts on growth are understudied. This study investigated the effect of MP-induced small intestinal histomorphological changes on growth performance of Oreochromis urolepis juveniles. Sixty larvae were exposed in control (0), 1, 10, and 100 polyethylene microplastic particles (PE MPs)/mL treatment groups. On day 65, juveniles were euthanized, dissected, and biometric data were taken. Small intestine histomorphological lesion index (HLI) was calculated following histological preparation using routine hematoxylin and eosin procedure. Results showed increase in HLI proportional to PE MPs exposure dose. These deteriorations equally reduced growth in final weight, weight gain and total length (One-Way ANOVA, p > 0.05), and Specific Growth Rate (SGR) (Kruskal–Wallis Test, p > 0.05), though there were insignificant differences between treatment groups. Condition factors of fishes in control and 1 PE MPs differed significantly and with other treatment groups (Tukey HSD, p < 0.05). Small intestines HLI correlated significantly with growth pattern (Spearman, r = 1.00, p = 0.01), condition factors (Pearson, r = −0.995, p < 0.05), final weight, weight gain, and total length (Spearman, r = −1.00, p = 0.01) but not with SGR. The allometric growth pattern changed towards isometric corresponding to increasing HLI. These findings suggest that MPs damaged small intestine structure and thus impaired digestion and nutrients absorption functions which disrupted growth. Such effects may impair juveniles’ ability to escape enemies, find food, and eventually reproduce, and therefore require further study.

Microplastics doi: 10.3390/microplastics1030024

Authors: Michela Volgare Roberto Avolio Rachele Castaldo Maria Emanuela Errico Hakim El Khiar Gennaro Gentile Andreja Sinjur Danilo Susnik Andrej Znidarsic Mariacristina Cocca

In recent years, microfibers released from synthetic fabrics have been identified as the main contributor to primary microplastic pollution. These pollutants have been detected in several products for human consumption. This work aims to evaluate the efficiency of a specific device used with the purpose to monitor and reduce this anthropogenic pollution in potable water. The device was tested using potable water from several cities in Slovenia by mounting the device containing the porous membrane directly to the faucet in private and public buildings. The results highlight the effectiveness of the applied device in removing natural and synthetic microfibers from tap water and confirm the abundance of microfibers as a contaminant of potable water.

Microplastics doi: 10.3390/microplastics1020023

Authors: Tony R. Walker

Plastic pollution has attracted considerable media attention from the public, governments, and industry in the past decade resulting in increased awareness of the direct environmental, economic and human health impacts [...]

Microplastics doi: 10.3390/microplastics1020022

Authors: Federica Pizzurro Sara Recchi Eliana Nerone Romolo Salini Nadia Beatrice Barile

Microplastics (MPs; <5 mm) are present throughout the marine environment and are recognized as an emerging threat to aquatic ecosystems. Filter feeding organisms, such as mussels, are considered as bioindicators of MP pollution and are useful to evaluate the potential risks of MPs to human health. The work presented shows data on potential MPs found in Mytilus galloprovincialis samples collected from the Adriatic Sea during two sampling sections (1st sampling: December 2019 and 2nd sampling: May 2020). The mussels were subjected to digestion with H2O2 individually and filtered and the MP elements found were observed using a stereomicroscope and ultimately categorized by shape, size class and color, with the aid of a digital camera and data acquisition software. The highest MP concentrations were observed in the mussels collected in December 2019 (1.11 microplastic items per gram wet weight of mussels’ tissue), highlighting the possible influence of the following two main factors: greater river discharges following adverse weather events and higher river water pollution due to industrial activities. Indeed, the second sampling was performed after the Italian lockdown, due to the COVID-19 emergency. MP fibers (50–80%) were the most abundant type of MPs identified, followed by fragments (10–40%), granules (1.5–2.5%), non-categorized shape (1–2%) and foam (<1%). The color black (50–70%) and sizes smaller than 500 µm were the most dominant characteristics recorded both in the 1st sampling (50–70%) and the 2nd survey (30–50%). These data could be overestimated, due to the lack of polymer identification. The results of this study provide further data on the importance of bivalves as environmental bioindicators with regard to the pollution of MPs in the Adriatic Sea, supporting their instrumental role as environmental bioindicators for MP pollution.

Microplastics doi: 10.3390/microplastics1020021

Authors: Serena Felline Manuela Piccardo Giuseppe Egidio De Benedetto Cosimino Malitesta Antonio Terlizzi

This study reports on the presence of microplastics in the gastrointestinal tracts and livers of demersal fish (the mullet, Mullus spp.) from a Marine Protected Area (Porto Cesareo) along the Ionian Sea coast (Apulia, Southern Italy). The results showed microplastic ingestion in more than 60% of specimens analyzed with an average of three items per fish and average levels in red mullets being almost twice as high as the average in the congeneric striped red mullets. The dominant polymers identified by Attenuated Total ReflectanceFourier Transform Infrared spectroscopy (ATR-FTIR) and Prolysis Gas Chromatography/Mass Spectrometry (Py-GCMS) analysis were polyethylene and polystyrene. Results can be used to set baseline levels for the assessment of microplastic pollution useful for the implementation of the Marine Strategy Framework Directive (MSFD) descriptor 10 in the Italian coast of Ionian Sea.

Microplastics doi: 10.3390/microplastics1020020

Authors: Stefania Federici Zahida Ademovic Mónica J. B. Amorim Moritz Bigalke Mariacristina Cocca Laura Eleonora Depero Joydeep Dutta Wolfgang Fritzsche Nanna B. Hartmann Gabriela Kalčikova Nicolas Keller Thomas C. Meisel Denise M. Mitrano Liam Morrison Jean-Marie Raquez Aleksandra Tubić Milica Velimirovic

Plastic fragments, weathered into or released in the form of micro- and nanoplastics, are persistent and widespread in the environment, and it is anticipated that they have negative environmental impacts. This necessitates immediate efforts for management strategies throughout the entire plastics lifecycle. This opinion paper was initiated by the EU COST Action CA20101 PRIORITY, which focuses on the need to develop an effective global networking platform dealing with research, implementation, and consolidation of ways to address the worldwide challenges associated with micro- and nanoplastics pollution in the environment.

Microplastics doi: 10.3390/microplastics1020019

Authors: Sylwia Rytelewska Agnieszka Dąbrowska

The aim of this paper is to contribute to the investigation of microplastics reaching the Baltic Sea with freshwater input. The scope of the paper was to analyze samples from several locations with different environmental characteristics. First, samples from urban areas differing in their degree of urbanization, a forest, a river and its watercourse were examined. Secondly, the ageing quantitative and qualitative characterization is discussed. Spectral techniques are crucial in identifying polymers, but the signal itself constitutes a valuable source of the crystallinity and density parameters of the polyethylene materials. The study indicates that polypropylene, polyethylene, polycarbonate and polystyrene are the most common types of microplastics in the investigated areas.

Microplastics doi: 10.3390/microplastics1020018

Authors: Keon Beigzadeh Julie M. Rieland Catherine B. Eastman David J. Duffy Brian J. Love

Inadvertent consumption of latent microplastics is a lethal challenge for developing creatures in aquatic environments. There are compelling needs to classify which kinds of plastics are most likely to be encountered by sea creatures and to develop mitigation strategies to reduce exposure. We analyzed an ensemble of microplastic particle fragments isolated from sea turtle post-hatchlings to identify their composition and other features and attributes. These microplastic particles were likely consumed by post-hatchlings because of the adsorbed biofilm formation mimicking normal food sources. Of the hundreds of particles that were collected, 30 were selected for analysis using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and density assessment to identify them compared with other compositional libraries. These thermophysical measurements were also compared with observational assessments via optical microscopy. Of the particles tested, nearly all were polyolefins such as polyethylene and polypropylene. The melting points of the extracted polymers were typically lower than for product grades of these resins, indicative of some level of degradation. Spectral analysis by FTIR often showed absorption indicative of new chemistries likely from both hydrolysis and biofilm growth observed on the surface that was subsequently investigated through surface abrading. Separate assessments of density of these particles were conducted and tended to reinforce identification via FTIR and DSC. The density results can be misleading if additives, fillers or biofilms that form alter the particle density relative to those of the neat resins. We suggest that since post-hatchlings commonly feed in the neritic or nearshore environment, less dense polymers are more likely to convey, thereby threatening sea turtle hatchlings who consume them inadvertently.

Microplastics doi: 10.3390/microplastics1020017

Authors: John J. Mbugani John F. Machiwa Daniel A. Shilla Wahabu Kimaro Dativa Joseph Farhan R. Khan

The histopathological effects of microplastics (MPs) in the gastrointestinal tracts of fish following long-term exposure and depuration are relatively understudied. This study investigated histomorphological damage in the small intestine of Oreochromis urolepis larvae following 65 d exposure to 38–45 μm of polyethylene microspheres (PE MPs) and after a recovery period of 60 d. Larval fish were assigned to each treatment group (control, 1, 10 and 100 PE MPs), where ingestion and degenerative changes in the small intestine were examined using a routine hematoxylin and eosin staining technique. The results highlighted significant PE MPs ingestion and retention proportional to exposure dose (χ2 = 49.54; df = 2). Villi height and width and epithelial cell height were significantly affected and differed between treatment groups. Indices of damage to the small intestine organ (χ2 = 47.37; df = 2; p < 0.05) and reaction patterns of villi, epithelial, goblet and cryptic glandular cells, leucocytic infiltration and blood congestion revealed significant occurrence of alteration as PE MPs exposure dose increased. After the recovery period, no PE MPs were observed, and villi height, width and epithelial cells showed recovery with no significant difference between treatment groups. Organ indices declined (χ2 = 12; df = 2; p < 0.05) but remained significantly different between treatment groups, largely due to leucocytic infiltration (χ2 = 9.08; df = 2; p < 0.05). The study demonstrated that microplastics induced small intestinal wall degeneration, but recovery in young fish occurred slowly. The damage likely compromised its digestive function, which may affect growth and reproduction. This requires further research.

Microplastics doi: 10.3390/microplastics1020016

Authors: Nadia Bouzid Christelle Anquetil Rachid Dris Johnny Gasperi Bruno Tassin Sylvie Derenne

Pyrolysis-GC/MS is increasingly used to quantify microplastics (MP) in environmental samples. In general, prior to analysis, purification steps are carried out to reduce the environmental matrix in sediment samples. The conventionally used protocol of density separation followed by digestion of organic matter does not allow for complete isolation of MP from the associated organic and mineral matter. Among the pyrolysis products used as indicator compounds for plastic polymers, some may originate from other substances present in the environmental samples. In this paper, the indicator compounds are reviewed for the most common polymers: PE, PP, PS, PET and PVC and selected taking into account potential interactions with substances present in environmental matrices. Even after a purification step, a residual mineral fraction remains in a sediment sample, including matrix effects. This effect may be positive or negative, depending on the investigated polymer and is thus important to consider when using Pyr-GC/MS for the quantification of MP in sediment samples. It also shows that no external calibration can be used to reliably quantify MP in such samples and that the use of internal standards is compulsory.

Microplastics doi: 10.3390/microplastics1010015

Authors: Thomas Senfter Andreas Walter Lukas Dür Florian Alber Martin Pillei

Despite the high number of scientific publications on related topics, such as sustainability, pollution control, etc., research on microplastic (MP) is still in its infancy. To advance the quality of future MP investigations, scientists have recently called for harmonization regarding the definition and categorization of MP, as well as for consensus in sampling and investigations methodologies. The application of standardized and fully characterized MP particles, which are commercially available on a large scale but rarely characterized by manufacturers, could add another piece to that mosaic. This publication aims to introduce ten low-priced MP powders that can be used as reference particles in future MP studies. The physical parameters shape, particle density and particle size distribution were examined, and results compared to technical information reports and data sheets, available. Particle densities were almost in line with the manufacturer’s information. However, significant leaks could be revealed for particle size specifications, thus underlining the demand for an accurate description of the particle size distribution, e.g., D50 or D90.

Microplastics doi: 10.3390/microplastics1010014

Authors: Ahmed K. Gad Stephen R. Midway

In the northern Gulf of Mexico, microplastics are reported in very high concentrations, which are thought to be partly sourced from the Mississippi River. This study sought to quantify microplastics across body size in two fish species, the hardhead catfish (Ariopsis felis) and southern flounder (Paralichthys lethostigma), common to Gulf of Mexico estuaries. We hypothesized that counts of ingested microplastics would be higher in smaller fishes than larger fishes. Fish were sampled in 2018 and 2019 across coastal Louisiana and represented a balanced range of length classes. Both species in our study ingested microplastics—25% of southern flounder and 15% of hardhead catfish. There was a significant positive effect of total length on microplastic loads in hardhead catfish. Due to the biological importance and management relevance of fish length, the study of microplastic loads and effects on fish may need to move beyond aggregating a species to considerations of individual size.

Microplastics doi: 10.3390/microplastics1010013

Authors: Carmen Sorasan Fernando E. Ortega-Ojeda Antonio Rodríguez Roberto Rosal

This work investigated the structural and chemical changes of plastics undergoing accelerated ageing upon irradiation that simulated the ultraviolet component of solar radiation for a five-year period. The plastics selected were polyethylene (PE) and polypropylene (PP) microplastic debris sampled from a sandy beach as well as pure pellets and fragments of objects made of the same polymers. We recorded Fourier Transform Infrared (FTIR) spectra at prescribed intervals during the irradiation procedure. The spectra were used to study the evolution of the absorption peaks usually associated with the environmental ageing of polyolefins, namely the peaks of hydroxyl and carbonyl stretching, the peaks relating to the presence of double bonds, and those associated with the crystallinity of PE and the tacticity of PP. The results showed that none of the usual degradation indexes followed a clear trend with increasing exposure and that the evolution of absorption peaks was not consistent among different fragments. We used the Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) method to process the whole information contained in the FTIR spectra in response to the chemical changes occurring during photochemical ageing. The results showed that the FTIR spectra contained sufficient information to cluster samples according to the irradiation received. Variable Importance of the Projection (VIP) analyses showed that the information for discriminating among different exposures was mainly contained in the absorption peaks corresponding to the hydroxyl and carbonyl stretching absorptions. The chemometric models had large determination coefficients, despite the large number of variables involved and could be applied to assess the environmental fate of plastics under environmental stressors.

Microplastics doi: 10.3390/microplastics1010012

Authors: Mel Constant Mathieu Reynaud Lisa Weiss Wolfgang Ludwig Philippe Kerhervé

Plastic waste and its fragments (microplastics, <5 mm) are a global, persistent, and ubiquitous threat for land and marine ecosystems. We have investigated the occurrence and composition of microplastics within 18 coastal fish species of the northwestern Mediterranean Sea. Digestive tracts were digested using hydrogen peroxide, and residues were observed under a stereo-microscope. Suspected microplastics were analyzed with a Fourier Transform InfraRed (FTIR) spectrometer to confirm its plastic nature and to identify the polymer type. A rigorous blank control and FTIR correction was applied, leading to the removal of 78% of the initially sorted and suspected particles. Corrected concentrations range from 0.00 to 5.15 items per fish, a result within the same range than this has been reported for other coastal species previously investigated in this area. Fibers, made of polyester (PES), polyamide (PA), acrylic (A) and polypropylene (PP), largely dominate the microplastic shapes (91%). A single driving force could not be identified, but several species traits (morphology, feeding, and habitat) may influence the number of ingested microplastics.

Microplastics doi: 10.3390/microplastics1010011

Authors: Paulina Piskuła Aleksander Maria Astel

Because of the increasing worldwide awareness concerning the occurrence of microplastics (MPs) in aquatic ecosystems, our goal was to analyze for the first time the quality and abundance of MPs and assess their seasonal variation in two unique rivers flowing through the low-land area in northern Poland. Their uniqueness is due to the fact they flow through landscape parks and urbanized zones, possess mountainous characteristics, and are aquatic habitats for sea trout (Salmo trutta m. trutta) and salmon (Salmo salar). In this pioneering study, the morphological types, geometric dimensions, and color of MP particles were analyzed by the use of an optical microscope. MPs particles were detected in 62.5% of the river water samples, while the average abundance was 3.6–4.2 items per sample. In terms of general seasonality, the sum of MPs items found in investigated river water samples decreased in the following order: spring (75 items) > summer (64 items) > autumn (52 items). Neither the total MPs abundance nor any morphological MPs types were statistically different between rivers according to single seasons. The quantity of MPs present in the river water was higher downstream of the wastewater treatment plant studied, which confirms that treated sewage effluent is a key source of MPs in an aquatic environment. Among the morphological types, fragments were prevalent among granules and fibers, while their average length not exceeding 1.0 mm enabled them to be classified as small. MPs were classified into nine colors, however, the bright colors were dominating only in the case of granule. In the case of the fragments and fibers, the dominating colors were transparent, white, blue, and black. Fourier transform infrared spectroscopy was performed on a small sample of microplastics (21.0%) due to their small size. Polymers containing polyethylene, polyvinyl chloride, polypropylene, polyester, and polystyrene were identified.

Microplastics doi: 10.3390/microplastics1010010

Authors: Juan José Alava Ana Tirapé Karly McMullen Miguel Uyaguari Gustavo A. Domínguez

COVID-19, caused by SARS-CoV-2, was declared a global pandemic on 11 March 2020 by the World Health Organization. The pandemic has triggered an unprecedented increase in the production, consumption and disposal of multiple types of plastic-based personal protective equipment (PPE) as a measure to reduce the infection. Recent research shows that plastic surfaces can serve as a fomite for coronavirus transmission as it can remain stable and be viable on polypropylene for up to 72 h or on other plastic surfaces for up to 9 days. While it is unknown whether or to what extent macroplastic debris and ubiquitous microplastics emitted into the environment can serve as physical vectors or fomites of pathogenic viruses, recent studies have reported that both macroplastic and microplastics can serve as vectors for harmful pathogens and invasive species (biological pollution). Here, hypothetical scenarios based on the weight of evidence are proposed to plausibly state the role of plastic debris (e.g., single-use-plastics), discarded PPE supplies, including facemasks, sanitizer bottles, gloves, and plastic bags, as well as microplastics as potential physical vectors of SARS-CoV-2, serving as a route of exposure to humans and wildlife in the terrestrial, freshwater and marine ecosystems.

Microplastics doi: 10.3390/microplastics1010009

Authors: Stefano Castelluccio Clara Bretas Alvim María Amparo Bes-Piá José Antonio Mendoza-Roca Silvia Fiore

Full-scale wastewater treatment facilities are not able to prevent microplastics (MPs) from discharging into natural waters and they are also associated with the land application of the sludge. This study evaluates the distribution of microfibers (MFs) in a lab-scale sequencing batch reactor (SBR) fed by synthetic wastewater (SW) for 93 days. The MFs were analyzed through optical microscopy in the mixed liquor (ML) and the effluent, and sulfuric acid digestion was applied to discriminate between natural and synthetic MFs (i.e., MPs). The results of the optical microscopy analyses were further validated through FTIR spectroscopy. A model describing the evolution over time of the MF concentration in the ML was created, accounting for the MFs entering the system through the SW and atmospheric deposition. The ratio between the MF concentration in the ML and the effluent was 1409 ± 781, demonstrating that MFs settle with the sludge. Consistently, in the ML, 64.9% of the recovered MFs were smaller than 1000 µm (average size 968 µm), while in the effluent, 76.1% of MFs were smaller than 1000 µm (average size 772 µm). Overall, 72% of MFs recovered from the ML were natural fibers and sulfuric acid digestion was successful in eliminating the natural MFs.

Microplastics doi: 10.3390/microplastics1010008

Authors: Javier Bayo Belén Ramos Joaquín López-Castellanos Dolores Rojo Sonia Olmos

This study investigates the ability of water-soluble detergent capsules to effectively release microplastics from their composition. A total of 39 different brands of water-soluble capsulated detergents were tested, 20 of them for washing machines and 19 for dishwashers, from four different countries in the EU, i.e., Spain, Portugal, Belgium, and Italy, as well as two different devices for microplastic recovery from laundry wastewater. Wastewater samples from all laundry capsules reported microplastics, mainly as entangled fibers from PET blankets, although none could be associated to capsule itself. This paper displays, through a calculated rate for microplastics, that fiber shedding from clothing maybe related to different detergent characteristics. Wastewater from both catching devices reported microplastics after their use, although samples from Guppyfriend bag displayed less fibers than those collected after the use of Cora Ball. Eventually, wastewater samples form dishwashing detergent capsules were much less contaminated with microplastics than those from laundry ones.

Microplastics doi: 10.3390/microplastics1010007

Authors: Avanthi Deshani Igalavithana Mahagama Gedara Y. L. Mahagamage Pradeep Gajanayake Amila Abeynayaka Premakumara Jagath Dickella Gamaralalage Masataka Ohgaki Miyuki Takenaka Takayuki Fukai Norihiro Itsubo

Microplastics (MPs) have been identified as an emerging soil pollutant and a global environmental concern. Scientists have recently paid attention to the contamination of soil by MPs as their detrimental impacts on soil systems are largely unknown. MPs are considered to be vectors for other soil contaminants, such as potentially toxic elements (PTEs) and organic contaminants. PTEs are persistent contaminants and are often released into soils in large quantities. MPs adsorb PTEs, mainly via electrostatic attraction and surface complexation, and increase their mobility in soils. These complexes can be easily absorbed by plants; hence, the accumulation of PTEs in plants can be enhanced in both microplastic and PTE contaminated soils. Furthermore, there is a high risk of food chains contamination by PTEs due to crops grown in both microplastic and PTE-contaminated soils. Consequently, countermeasures including policy- and governance-based approaches that target circular economy as well as reduce, reuse, recycle (3R) applications are being discussed around the world to minimize the environmental contamination of MPs.

Microplastics doi: 10.3390/microplastics1010006

Authors: Katerina Karkanorachaki Panagiota Tsiota Giorgos Dasenakis Evdokia Syranidou Nicolas Kalogerakis

Concern regarding the pollution of the marine environment with plastics has been rising in recent years. Plastic waste residing in and interacting with the environment fragments into secondary particles in the micro- and nanoscale, whose negative impacts on the environment are even greater than those of the parent items. In this work, secondary high density polyethylene (HDPE) and low density polyethylene (LDPE) microplastics were produced by irradiation of virgin films following mechanical fragmentation. The fragments with size ranging from 250 μm to 2 mm were selected for subsequent microcosm experiments. Incubation for 120 days in seawater inoculated with two marine communities, Agios, acclimatized to utilizing plastics as a carbon source, and Souda, as was collected at the Souda bay (Crete, Greece), resulted in biofilm formation by polyethylene (PE) degraders. Monthly FTIR (Fourier-transform infrared spectroscopy) examination of the samples revealed changes in the chemical structure of the surface of the polymers. Dynamic light scattering (DLS) was employed and nano- and microparticles with sizes in the range between 56 nm and 4.5 μm were detected in the seawater of inoculated microcosms. It was thus demonstrated that weathered plastics particles can biodeteriorate and biofragment as a result of biofilm attachment, resulting in the production of nanoplastics due to microbial activity.

Microplastics doi: 10.3390/microplastics1010005

Authors: Emma Caitlin Hunter Raquelle de Vine Olga Pantos Phil Clunies-Ross Fraser Doake Hayden Masterton Robert A. Briers

Plastic pollution is threatening aquatic ecosystems and wildlife. Understanding the characteristics and extent of plastic pollution is the first step towards improving management and therefore the environmental impacts. Pre-production pellets are used in the manufacture of a range of consumer items. The Avon–Heathcote Estuary/Ihutai in Aotearoa–New Zealand, an important wildlife habitat, was assessed for the presence and characteristics of pre-production pellets. Following a visual survey of the estuary’s perimeter to establish overall levels, seven accumulation hotspots were identified, and surveyed in more detail. The enumeration and characterisation of pellet colour, size, morphology, degree of weathering and polymer type was undertaken. A total of 3819 pellets were identified, with pellets present at all sites. The pellets were predominantly clear (86%), 3 mm in size (54%), cylindrical in shape (62%), showed moderate weathering (41%) and were made of low-density polyethylene (LDPE) (53%). Pellet abundance and characteristics varied between sites. Accumulation and abundance may be influenced by river inflows along which plastic manufacturers are located, weather conditions, locality to stormwater outlets and pellet characteristics. Pellet pollution is a notable problem in the Avon–Heathcote Estuary/Ihutai and it highlights the need to better understand the sources and improve best management practices.

Microplastics doi: 10.3390/microplastics1010004

Authors: Anna MacDonald Deonie Allen Elsa João

The problems of plastic pollution are increasing and have been linked to sustainability efforts. Some communities have tried to tackle this issue by implementing ‘plastic free’ initiatives, such as the ‘Plastic Free Community’. Community initiatives foster change and encourage improved environmental outcomes; however, it is unclear if ‘plastic free’ initiatives have the capacity to ‘snowball’ into further sustainable behaviors or if they are a ‘distraction’ from more pressing environmental issues. This study presents the behavioral changes, snowball and distraction effects from the first Scottish mainland ‘plastic free community’ initiative. The pilot study of ‘Plastic Free Anstruther’ (Scotland) identifies self-transcending values and locus of control as important drivers for change, but adoption of single-use plastic alternatives and a ‘single use’ mindset resulted in a limited ‘snowball’ effect. Future ‘Plastic Free Community’ initiatives should focus on encouraging more circular approaches and individual behavior change to reduce waste and improve environmental outcomes. While the initiative resulted in greater awareness of wider environmental issues, additional incentives for individual and business pro-environmental behavior could further improve economic, social and environmental sustainability.

Microplastics doi: 10.3390/microplastics1010003

Authors: Amarachi Onyena Donald Aniche Bright Ogbolu Md. Rakib Jamal Uddin Tony Walker

Threats emerging from microplastic pollution in the marine environment have received much global attention. This review assessed sources, fate, and impacts of microplastics in marine ecosystems and identified gaps. Most studies document the ubiquity of microplastics and associated environmental effects. Effects include impacts to marine ecosystems, risks to biodiversity, and threats to human health. Microplastic leakage into marine ecosystems arises from plastic waste mismanagement and a lack of effective mitigative strategies. This review identified a scarcity of microplastics’ mitigation strategies from different stakeholders. Lack of community involvement in microplastic monitoring or ecosystem conservation exists due to limited existence of citizen science and stakeholder co-management initiatives. Although some management strategies exist for controlling effects of microplastics (often implemented by local and global environmental groups), a standardized management strategy to mitigate microplastics in coastal areas is urgently required. There is a need to review policy interventions aimed at plastic reduction in or near coastal ecosystems and evaluate their effectiveness. There is also a need to identify focal causes of microplastic pollution in the marine environment through further environmental research and governance approaches. These would extend to creating more effective policies as well as harmonized and extended efforts of educational campaigns and incentives for plastic waste reduction while mandating stringent penalties to help reduce microplastic leakage into the marine environment.

Microplastics doi: 10.3390/microplastics1010002

Authors: Refilwe Precious Mofokeng David Glassom

Once in the environment, preproduction plastic polymers between 2–5 mm in size, also known as pellets, can cause physical harm to animals that mistake them for food as they have been reported to accumulate toxic substances, including on their surface. However, the rate of metal enrichment on pellets is not well investigated. In October 2018, Durban experienced a storm that resulted in ±2000 tons of polyethylene pellets being spilt into Durban Harbour, which caused environmental pollution concerns. This event provided a unique opportunity to study metal accumulation on pellets. Pellets were collected at one-month intervals for 6 months following the spill from October 2017 to March 2018, and metal concentrations were compared to concentrations found on pellets collected before the spill. The pellets were digested using a mixture of concentrated nitric acid (55%) and sulphuric acid (60%) at a ratio of 3:1 and analysed for numerous trace metals (Al, As, Pb, Cd, Cr, Fe, Cu, Mn, Ni, and Zn) using the Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Pellets collected in Durban Harbour prior to the spill in a related study (unpublished data) showed higher metal accumulation; however, there was no evident linear increase in metal concentration in pellets over time. ANOVA showed no significant difference for all metals (p > 0.05) in metal concentration between months; however, there was a significant difference between aged and newly introduced pellets.

Microplastics doi: 10.3390/microplastics1010001

Authors: Nicolas Kalogerakis

Microplastics is a new, open-access, peer-reviewed journal by MDPI that will provide an advanced forum for scientists to discuss the challenges faced by the ubiquitous presence of microplastics in the environment, as well as their impact on human health and ecosystem services [...]