Many studies have reported the occurrence of microplastics in different environmental compartments, through the description of their morphological characteristics and chemical identification, obtained mainly by spectroscopic techniques. However, the scientific community still lacks the implementation of standardized analytical methods that aim to assess not only the identification of the particle, but also its stage of degradation. It is understood that this information would be extremely useful in helping elucidate the main sources of pollution and contributing to strategies and mitigating measures for the management of solid waste and microplastics in the environment. In this respect, the aim of this study was to evaluate the efficiency of Fourier-transform infrared spectroscopy, Raman spectroscopy, carbon elemental analysis coupled with mass spectrometry, and scanning electron microscopy with energy dispersive X-ray spectrometry for the characterization of virgin and aged polyethylene and polypropylene microplastics samples. The degraded samples were subjected to accelerated aging in a QUV chamber in accordance with American standard for measuring accelerated weather testing (ASTM G-154). This work discusses the efficiency and limitations of each technique for the detailed chemical characterization of microplastic samples collected from the environment.
Microplastics are environmental contaminants consisting of small plastics ≤ 5 mm. Concerns over the adverse effects of microplastics have led to a rapid growth in the available literature despite the lack of harmonized methods and materials. Therefore, the field is becoming increasingly daunting to new researchers. A state-of-the-art guide was assembled following a comprehensive literature review of microplastics research with the intent of addressing contemporary challenges, prioritized based on a survey, and introducing best practices. The lack of standardized methods and reference materials, the lack of access to analytical equipment, and the difficulty in working with lower environmental concentrations in laboratory tests (e.g., toxicity assays) remain a great challenge. The present work addresses these issues across three main sections: definitions, sampling, and evaluation of adverse effects. Harmonized methods and greater collaboration were identified as opportunities in this rapidly evolving field. A review of available interlaboratory comparison tests was also conducted to support additional recommendations.
Growing concern about the impact of plastic pollution on the environment has led to the creation of global public policies and the consumption of “environmentally friendly” products, such as oxy-biodegradable plastics. In this context, “greenwashing” practices can arise, i.e., the product promises more environmental benefits than it actually offers, which can lead to superfluous use, inappropriate disposal, and the generation of microplastics (MPs). However, the scientific literature lacks studies that evaluate the behavior of oxy-biodegradable plastic when exposed to the freshwater environment. In this respect, the aim of the current study was to evaluate the degradation process of oxy-biodegradable plastic bags made from high-density polyethylene (HDPE) in river water. To this end, the current study aimed to assess whether these bags actually meet the label information (which corresponds to the complete degradation of material) or whether they correspond to greenwashing practices. The physical and chemical alterations, and the formation of biological communities that occurred on the surface of the plastic material when exposed to natural aging and submerged in freshwater were monitored using mid-infrared absorption spectroscopy with attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM). The characterization of the samples after 180 days of exposure showed that the oxy-biodegradable bags were not completely degraded, with only fragmentation of the material and generation of MPs. In addition, it was also observed that microorganisms present in the water easily colonized the plastic surface from the start of the experiment. In this way, the oxy-biodegradable bags analyzed correspond to a greenwashing practice, which is extremely harmful, since it can influence the increase in consumption of these products, generating greater improper disposal of these materials, and consequently the generation of MPs and the formation of biofilms, which can carry pathogenic microorganisms to the aquatic biota and to humans.
Per- and poly-fluoroalkyl substances (PFAS) represent an extensive and expanding group of chemicals considered contaminants of emerging concern (CECs). These elements have found widespread usage in diverse industrial and commercial sectors since the 1940s. The advancement of modern analytical methods in developed countries has significantly contributed to the increased research on the environmental behavior and risk assessment of PFAS. However, what about developing countries? Over time, the focus on PFAS has expanded beyond legacy PFAS to encompass novel ones. In this perspective, we focus on analyzing the existing knowledge concerning PFAS in the marine environment, aiming to shed light on the limited research pertaining to per- and polyfluoroalkyl pollution in the marine ecosystems of Africa.
Carbon-based adsorbents, such as graphene, graphene oxide (GO), activated carbon/biochar (AC/BC), carbon nanotubes (CNTs), metal-modified carbon, and fly ash, are garnering increasing attention due to their exceptional structural properties, enabling their potential effectiveness in removing microplastics and nano-plastics (MPs/NPs) from aqueous solutions. A key attribute contributing to the efficacy of these carbon adsorbents in addressing MPs/NPs is their flexibly tunable surface properties. To advance the applicability of functionalized carbon adsorbents in the context of MPs/NPs removal, it is necessary to highlight their interactions with MPs/NPs in aqueous environments. The review commences by outlining the main adsorption mechanisms. Subsequently, the adsorption behavior of different types of MPs/NPs on carbon-based adsorbents is analyzed and how different factors influence their adsorption performance is examined. Finally, the review concludes by offering insights into prospective avenues for future research concerning functional carbon adsorbents for MPs/NPs removal.
Microplastics’ ecotoxicological potential in almost all ecosystems makes them a global environmental issue. This review evaluates Southeast Asian microplastic contamination data from 2013 to 2023. This evaluation examined 285 research publications from Scopus, Web of Science, and ScienceDirect, mostly on sediment and water matrices. Based on their size, shape, polymer type, and potential risks from polymer hazards in Southeast Asian countries, this analysis assesses microplastic pollution in biota, sediment, water, and other environmental matrices. The majority of microplastics in this region are small (46%) and large (32%). Within the biota matrix, small microplastics (SMP) and large microplastics (LMP) dominated. Fibers predominated in all matrices, particularly the biota matrix. Polyethylene emerged as the most abundant polymer type (22%), found in all four matrices. Despite being less abundant, polyurethane and polyamide have high hazard scores, raising ecological concerns due to their detrimental effects on environmental matrices. According to the analyzed data, Southeast Asian countries face significant risks due to high levels of microplastic contamination in water, sediments, biota, and other matrices. However, there are noticeable discrepancies in Southeast Asian data, indicating progress in microplastic research, with most data coming from Indonesia, Thailand, Malaysia, Vietnam, and the Philippines and little information in the literature regarding microplastic contamination from East Timor, Laos, Brunei, Myanmar, and Cambodia.
Sewage treatment plants are designed to handle wastes that include several types of pollutants, including microplastics (MPs), which are synthetic polymer materials fragmented to sizes < 5 mm. Investigating the abundance and removal efficiency rates of MPs in wastewater treatment plants is important because the water body to which plant effluents are discharged may be adversely affected by the released MPs. Therefore, the abundance, characteristics, and removal of MPs at two sewage treatment plants located on the southwest coast of Norway are studied. Twenty-four samples were collected across two sampling sessions by using an ad hoc-designed plastic-free water sampling device, which was improved by applying a cascade of certified stainless-steel sieves. A combined sequence of enzymatic and strong oxidative incubations was performed for sample preparation. The obtained samples were chemically characterized and quantified using thermoanalytical techniques. The overall amounts of polymers in the inlet wastewater and outlet water were 366-616 μg/L and