Plastic breath: Quantification of microplastics and polymer additives in airborne particles.

The widespread extensive use of synthetic polymers has led to a substantial environmental crisis caused by plastic pollution, with microplastics detected in various environments and posing risks to both human health and ecosystems. The possibility of plastic fragments to be dispersed in the air as particles and inhaled by humans may cause damage to the respiratory and other body systems. Therefore, there is a particular need to study microplastics as air pollutants. In this study, we tested a combination of analytical pyrolysis, gas chromatography-mass spectrometry, and gas and liquid chromatography-mass spectrometry to identify and quantify both microplastics and their additives in airborne particulate matter and settled dust within a workplace environment: a WEEE treatment plant. Using this combined approach, we were able to accurately quantify ten synthetic polymers and eight classes of polymer additives. The identified additives include phthalates, adipates, citrates, sebacates, trimellitates, benzoates, organophosphates, and newly developed brominated flame retardants.

Effects of microplastics on microbial community dynamics in sediments from the Volturno River ecosystem, Italy.

In this study, the sources, abundance, and ecological implications of microplastic (MP) pollution in Volturno, one of the main rivers in southern Italy, were explored by investigating the MP concentration levels in sediments collected along the watercourse. The samples were sieved through 5- and 2-mm sieves and treated with selective organic solvents. The polymer classes polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), nylon 6 (PA6), and nylon 6,6 (PA66) were quantified using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and high-performance liquid chromatography (HPLC). Furthermore, a 16S rRNA metagenomic analysis was performed using next-generation sequencing in Ion Torrent™ to explore the bacterial taxonomy and ecological dynamics of sediment samples. The MPs were detected in all samples collected from the study area. PP and PET were the most abundant and frequently detected polymer types in the analysed samples. The total MP concentration ranged from 1.05 to 14.55 ppm (parts per million), identifying two distinct data populations: high- and low-MP-contaminated sediments. According to the Polymer Hazard Index (PHI), MP pollution was categorised as hazard levels III and IV (corresponding to the danger category). Metagenomic data revealed that the presence of MPs significantly affected the abundance of bacterial taxa; Flavobacteraceae and Nocardiaceae, which are known to degrade polymeric substances, were present in high-MP-contaminated sediments. This study provides new insights into the ecological relevance of MP pollution and suggests that microorganisms may serve as biomarkers of MP pollution.

Microplastic pollution in the sediments of interconnected lakebed, seabed, and seashore aquatic environments: polymer-specific total mass through the multianalytical "PISA" procedure.

The total mass of individual synthetic polymers present as microplastic (MP < 2 mm) pollutants in the sediments of interconnected aquatic environments was determined adopting the Polymer Identification and Specific Analysis (PISA) procedure. The investigated area includes a coastal lakebed (Massaciuccoli), a coastal seabed (Serchio River estuarine), and a sandy beach (Lecciona), all within a natural park area in Tuscany (Italy). Polyolefins, poly(styrene) (PS), poly(vinyl chloride) (PVC), polycarbonate (PC), poly(ethylene terephthalate) (PET), and the polyamides poly(caprolactame) (Nylon 6) and poly(hexamethylene adipamide) (Nylon 6,6) were fractionated and quantified through a sequence of selective solvent extractions followed by either analytical pyrolysis or reversed-phase HPLC analysis of the products of hydrolytic depolymerizations under acidic and alkaline conditions. The highest concentrations of polyolefins (highly degraded, up to 864 µg/kg of dry sediment) and PS (up to 1138 µg/kg) MPs were found in the beach dune sector, where larger plastic debris are not removed by the cyclic swash action and are thus prone to further aging and fragmentation. Surprisingly, low concentrations of less degraded polyolefins (around 30 µg/kg) were found throughout the transect zones of the beach. Positive correlation was found between polar polymers (PVC, PC) and phthalates, most likely absorbed from polluted environments. PET and nylons above their respective LOQ values were found in the lakebed and estuarine seabed hot spots. The pollution levels suggest a significant contribution from riverine and canalized surface waters collecting urban (treated) wastewaters and waters from Serchio River and the much larger Arno River aquifers, characterized by a high anthropogenic pressure.

Magic extraction: solid-phase extraction and analytical pyrolysis to study polycyclic aromatic hydrocarbon and polychlorinated biphenyls in freshwater.

Polycyclic aromatic hydrocarbons and polychlorinated biphenyls are commonly categorized as persistent organic pollutants. In order to analyze these pollutants, customized stationary phases are increasingly being developed and synthesized for solid-phase extraction. In this work, we tested a new solventless solid-phase extraction approach based on the use of a Magic Chemisorber® (Frontier Lab) which consists of a bead-covered polydimethylsiloxane stationary phase with a thickness of 500 µm. These devices are directly immersed into aqueous samples and then introduced into a pyrolysis-gas chromatography-mass spectrometry system equipped with a cryofocusing system for the thermal desorption and analysis of the adsorbed species. Our new method performs better than the most recent solid-phase extraction devices, with limits of detection lower than 2.7 ng/L and limits of quantification lower than 9.0 ng/L. The method was tested on standard compounds and on an environmental sample, showing the potential to characterize other chemical species besides the persistent organic pollutants, such as phthalate plasticizers and antioxidants.

Leached degradation products from beached microplastics: A potential threat to coastal dune plants.

Plants play a fundamental role in maintaining coastal dunes but also accumulate littered microplastics (MPs). Migration tests suggest that naturally weathered MPs can leach out a broader range of potentially phytotoxic chemicals than virgin MPs. Thus, assessing MPs effects on plants using beached-collected particles rather than virgin ones is critically important. Here, the effects on plants of leachates from two pools of beach-collected and virgin MPs, high-density polyethylene (HDPE) and polypropylene (PP), and their mixture, were explored combining toxicity tests and chemical analyses. Phytotoxicity of MP leachates at different dilutions was evaluated under standard laboratory conditions using test species and under environmentally realistic conditions using the dune species Thinopyrum junceum. Leachates from beached PP and HDPE adversely affected all species, and the extent of these effects varied according to polymer type, concentration, and species. Virgin MPs had weaker effects than beached ones. Several potentially phytotoxic oxidized compounds were detected in water by GC/MS analysis, and their amount estimated. Results indicate that the molecular species leaching from beached MPs - at ppm concentration levels for the individual chemical species - can inhibit plant growth, and the effects of leachates from mixtures of degraded MPs can differ from those from individual polymers, highlighting the need for further investigation of MPs consequences for coastal ecosystems.

Seeping plastics: Potentially harmful molecular fragments leaching out from microplastics during accelerated ageing in seawater.

Microplastics are the particulate plastic debris found almost everywhere as environmental contaminants. They are not chemically stable persistent pollutants, but reactive materials. In fact, synthetic polymers exposed to the environment undergo chemical and physical degradation processes which lead not only to mechanical but also molecular fragmentation, releasing compounds that are potentially harmful for the environment and human health. We carried out accelerated photo-oxidative ageing of four reference microplastics (low- and high-density polyethylene, polypropylene, and polystyrene) directly in artificial seawater. We then made a characterization at the molecular level along with a quantification of the chemical species leached into water. Gas chromatography/mass spectrometry analyses performed after selective extraction and derivatization enabled us to identify more than 60 different compounds. Analysis of the leachates from the three polyolefins revealed that the main degradation products were mono- and dicarboxylic acids, along with linear and branched hydroxy acids. The highest amount of leached degradation species was observed for polystyrene, with benzoic acid and phenol derivatives as the most abundant, along with oligomeric styrene derivatives. The results from reference microplastics were then compared with those obtained by analyzing leachates in artificial seawater from aged plastic debris collected in a natural environment. The differences observed between the reference and the environmental plastic leachates mainly concerned the relative abundances of the chemical species detected, with the environmental samples showing higher amounts of dicarboxylic acids and oxidized species.

Detection of plastic particles in marine sponges by a combined infrared micro-spectroscopy and pyrolysis-gas chromatography-mass spectrometry approach.

Plastic pollution threatens the marine environment, especially due to the adverse effects caused by micro and nano particles interacting with the marine biota. In order to provide reliable data regarding micro and nanoplastic contamination and the related impacts, efficient analytical solutions are needed. We developed a new analysis workflow that uses marine sponges to monitor plastic pollution by characterizing the plastic particles accumulated in their tissue. Specimens of cf. Haliclona (Haplosclerida) were sampled in the Maldivian archipelago. The aim was to optimize the method and to carry out a pilot study of the contamination of the related reef habitat. Particles were isolated, size fractioned, counted and submitted to morphological and chemical characterization. The constituting polymer was identified by infrared microspectroscopy for particles >25 µm, and by pyrolysis coupled with gas chromatography mass spectrometry for those <25 µm. Method recoveries were between 87 and 83% and limits of quantitation (LOQs) were between 6.6 and 30.2 ng/g. Analyses showed that 70% of the sponges presented plastic contamination, with an average of 1.2 particles/g tissue for the 25-150 µm size range, and a total plastic concentration of up to 4.8 µg/g in the 0.2-25 µm size range, with polyolefin being the most represented polymer in both size ranges. Overall, the study demonstrated the reliability of the proposed analytical workflow and of the use of sponges as biosamplers for plastic particles.

A Systematic Study on the Degradation Products Generated from Artificially Aged Microplastics.

Most of the analytical studies focused on microplastics (MPs) are based on the detection and identification of the polymers constituting the particles. On the other hand, plastic debris in the environment undergoes chemical and physical degradation processes leading not only to mechanical but also to molecular fragmentation quickly resulting in the formation of leachable, soluble and/or volatile degradation products that are released in the environment. We performed the analysis of reference MPs-polymer micropowders obtained by grinding a set of five polymer types down to final size in the 857-509 µm range, namely high- and low-density polyethylene, polystyrene (PS), polypropylene (PP), and polyethylene terephthalate (PET). The reference MPs were artificially aged in a solar-box to investigate their degradation processes by characterizing the aged (photo-oxidized) MPs and their low molecular weight and/or highly oxidized fraction. For this purpose, the artificially aged MPs were subjected to extraction in polar organic solvents, targeting selective recovery of the low molecular weight fractions generated during the artificial aging. Analysis of the extractable fractions and of the residues was carried out by a multi-technique approach combining evolved gas analysis-mass spectrometry (EGA-MS), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), and size exclusion chromatography (SEC). The results provided information on the degradation products formed during accelerated aging. Up to 18 wt% of extractable, low molecular weight fraction was recovered from the photo-aged MPs, depending on the polymer type. The photo-degradation products of polyolefins (PE and PP) included a wide range of long chain alcohols, aldehydes, ketones, carboxylic acids, and hydroxy acids, as detected in the soluble fractions of aged samples. SEC analyses also showed a marked decrease in the average molecular weight of PP polymer chains, whereas cross-linking was observed in the case of PS. The most abundant low molecular weight photo-degradation products of PS were benzoic acid and 1,4-benzenedicarboxylic acid, while PET had the highest stability towards aging, as indicated by the modest generation of low molecular weight species.

New methodologies for the detection, identification, and quantification of microplastics and their environmental degradation by-products.

Sampling, separation, detection, and characterization of microplastics (MPs) dispersed in natural water bodies and ecosystems is a challenging and critical issue for a better understanding of the hazards for the environment posed by such nearly ubiquitous and still largely unknown form of pollution. There is still the need for exhaustive, reliable, accurate, reasonably fast, and cost-efficient analytical protocols allowing the quantification not only of MPs but also of nanoplastics (NPs) and of the harmful molecular pollutants that may result from degrading plastics. Here a set of newly developed analytical protocols, integrated with specialized techniques such as pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS), for the accurate and selective determination of the polymers most commonly found as MPs polluting marine and freshwater sediments are presented. In addition, the results of an investigation on the low molecular weight volatile organic compounds (VOCs) released upon photo-oxidative degradation of microplastics highlight the important role of photoinduced fragmentation at a molecular level both as a potential source of hazardous chemicals and as accelerators of the overall degradation of floating or stranded plastic debris.

Microwave-assisted solvent extraction and double-shot analytical pyrolysis for the quali-quantitation of plasticizers and microplastics in beach sand samples.

Pollution from microplastics (MPs) needs to be evaluated by deploying reliable analytical techniques that provide qualitative and quantitative data on the extent of contamination in the various environmental matrices. Solvent extraction of MPs followed by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) provides data that not only regard the soluble plastics, but also the organic additives contained in MPs and the low-molecular weight degradation products of insoluble plastics. In this study, the potential of microwave-assisted solvent extraction and double-shot Py-GC-MS was investigated in order to obtain quali-quantitative information on polystyrene and on phthalate plasticizers in environmental samples. The method was validated and provided recoveries higher than 96 %, and detection limits lower than 1 ng and 1 µg for phthalates and polystyrene, respectively. We used the method to analyze samples of sand collected from a shoreline in Tuscany (central Italy) and thereby determine the content of phthalates and polystyrene at different depths and distances from the coastline. Qualitative data were also obtained regarding the presence of oxidation products derived from polyethylene and polypropylene. The different contents of plasticizers, plastics, and degradation products in the investigated samples are discussed in relation to how environmental agents affect the leaching and degradation processes of the polymers.

Plastics in Heritage Science: Analytical Pyrolysis Techniques Applied to Objects of Design.

The first synthetic polymers were introduced as constituents of everyday life, design objects, and artworks at the end of the 19th century. Since then, the history of design has been strictly connected with the 20th century evolution of plastic materials. Objects of design from the 20th century are today a precious part of the cultural heritage. They raise specific conservation issues due to the degradation processes affecting synthetic polymer-based plastics. Museums and collections dealing with the conservation of design objects and modern materials need to base their conservation strategies on compositional data that reveal the formulations of historical plastics and their decay processes. Specific and specifically optimized analytical tools are thus needed. We employed flash analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS) and evolved gas analysis coupled with mass spectrometry (EGA-MS) to characterize "historic polymeric materials" (HIPOMS) and heritage plastics at the molecular level with high chemical detail. This approach complements non-invasive spectroscopic diagnosis whenever it fails to obtain significant or complete information on the nature and the state of preservation of the materials under study. We determined the composition of several 20th century design objects (1954-1994) from the Triennale Design Museum of Milan (Triennale Milano - Museo del Design Italiano), which for different morphological, chemical, or physical reasons were unsuitable for characterization by non-invasive spectroscopy. EGA-MS proved capable for the study of the different fractions constituting heterogeneous micro-samples and for gaining an insight into their degradation processes from the contextual interpretation of thermal and mass-spectrometric data.