Limited exposure of captive Australian marsupials to plastics.

The global concern regarding the ubiquitous presence of plastics in the environment has led to intensified research on the impact of these materials on wildlife. In the Australian context, marsupials represent a unique and diverse group of mammals, yet little is known about their exposures to plastics. This study aimed to assess the contamination levels of seven common plastics (i.e., polystyrene (PS), polycarbonate (PC), poly-(methyl methacrylate) (PMMA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), and polyvinyl chloride (PVC)) in both the diet and faeces of kangaroos, wallabies and koalas sampled from a sanctuary in Northeastern Australia. Quantitative analysis was performed by pressurized liquid extraction followed by double-shot microfurnace pyrolysis coupled to gas chromatography mass spectrometry. Interestingly, the analysis of the food and faeces samples revealed the absence of detectable plastic particles; with this preliminary finding suggesting a relatively limited exposure of captive Australian marsupials to plastics. This study contributes valuable insights into the current state of plastic contamination in Australian marsupials, shedding light on the limited exposures and potential risks, and highlighting the need for continued monitoring and conservation efforts. The results underscore the importance of proactive measures to mitigate plastic pollution and protect vulnerable wildlife populations in Australia's unique ecosystems.

Mass quantification of nanoplastics at wastewater treatment plants by pyrolysis-gas chromatography-mass spectrometry.

Municipal wastewater treatment plants (WWTPs) play a crucial role in the collection and redistribution of plastic particles from both households and industries, contributing to their presence in the environment. Previous studies investigating the levels of plastics in WWTPs, and their removal rates have primarily focused on polymer type, size, shape, colour, and particle count, while comprehensive understanding of the mass concentration of plastic particles, particularly those <1 µm (nanoplastics), remains unclear and lacking. In this study, pyrolysis gas chromatography-mass spectrometry was used to simultaneously determine the mass concentration of nine selected polymers (i.e., polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), nylon 6, nylon 66, polyvinylchloride (PVC), poly(methyl methacrylate) (PMMA) and polycarbonate (PC)) below 1 µm in size across the treatment processes or stages of three WWTPs in Australia. All the targeted nanoplastics were detected at concentrations between 0.04 and 7.3 µg/L. Nylon 66 (0.2-7.3 µg/L), PE (0.1-6.6 µg/L), PP (0.1-4.5 µg/L), Nylon 6 (0.1-3.6 µg/L) and PET (0.1-2.2 µg/L), were the predominant polymers in the samples. The mass concentration of the total nanoplastics decreased from 27.7, 18 and 9.1 µg/L in the influent to 1, 1.4 and 0.8 µg/L in the effluent, with approximate removal rates of 96 %, 92 % and 91 % in plants A, B and C, respectively. Based on annual wastewater effluent discharge, it is estimated that approximately 24, 2 and 0.7 kg of nanoplastics are released into the environment per year for WWTPs A, B and C, respectively. This study investigated the mass concentrations and removal rates of nanoplastics with a size range of 0.01-1 µm in wastewater, providing important insight into the pollution levels and distribution patterns of nanoplastics in Australian WWTPs.

Plastic pollution in Moreton Bay sediments, Southeast Queensland, Australia.

The mounting issue of plastic waste in the aquatic ecosystem is a growing source of concern. Most plastic waste originates on land and a significant proportion of this eventually finds its way into the marine environment, which is widely regarded as a major repository for plastic debris. Currently, there exists a substantial gap in our understanding of how much plastic, the main polymer types, and the distribution of plastic in the marine environment. This study aimed to provide information on mass concentrations of a range of plastics in the surface sediments in the semi-enclosed Moreton Bay, just offshore the large city of Brisbane, Southeast Queensland, Australia. Surface sediment samples were quantitatively analysed for a suite of 7 common plastic polymer types (i.e., polystyrene (PS), polycarbonate (PC), poly-(methyl methacrylate) (PMMA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE) and polyvinyl chloride (PVC)) using a pressurized liquid extraction (PLE) followed by double-shot microfurnace pyrolysis coupled to gas chromatography mass spectrometry (Pyr-GC/MS). The advantage of this approach is that it can measure plastics below the limit of visual detection. The study revealed that Σ7plastics were consistently present in the samples, although the concentrations displayed a wide range of concentrations from 3.3 to 2194.2 µg/g across different sites. Among the polymers analysed, PE and PVC were found at the highest concentrations, ranging from 2.3 to 1885.9 µg/g and 3.0-979.5 µg/g, respectively. Based on the average concentrations of plastics measured, the dry bulk density and volume of sediments within the top 10 cm of the bay, it was estimated that there is a minimum of 7000 t of plastics stored in the surface sediments of the bay. This study is the first to report the mass concentrations of identified plastics and identify the main polymer types in Moreton Bay. This is important information to develop management plans to reduce the plastic waste entering the coastal marine environment.

Tracing the origins of plastics in biosolids: The role of sewerage pipe materials and trade waste.

Plastics are ubiquitous in virtually every environment on earth. While the specific sources of plastics entering wastewater are not well known, growing evidence suggests sewage sludge (biosolids) can be a sink for plastics. One potential source could be the sewerage pipe materials used to transport sewage between premises and wastewater treatment plants (WWTPs). To evaluate the significance of sewerage piping as a source of biosolids plastics concentrations, we compared the proportion of the total network (by length and surface area) of polyethylene (PE), polyvinylchloride (PVC), and polypropylene (PP) pipes from 10 WWTPs against their biosolids mass concentrations (mg plastic/g biosolid). Among the 10 catchments, the percentage of the network consisting of PP piping ranged from 0 to 1 %, with 0.8-21 % for PE, and 8-73 % for PVC. Biosolids plastics concentrations ranged from 0.09 to 8.62 mg/g (mg plastic/g biosolid) for PP and PE, respectively. For all three plastics, there was no significant Pearson correlation (r < 0.4) between the biosolids concentration (dry weight mg/g) and the proportion of the network material of the sewerage piping as plastic (either length or surface area). A comparison of trade waste entering a subset of 6 WWTP showed the highest biosolid principal components analysis (PCA) associations between loads of plastics (g/day) and automotive wash bays, general manufacturing, hospitals, laboratories, food manufacturing, laundry and dry cleaning, and cooling towers. A stepwise regression analysis indicated pipe length and surface area, as well as automotive wash bays and food manufacturing may be significant. While our data gave mixed results on the attribution of the sources of plastics entering WWTPs, it suggests that sewerage infrastructure and trade waste may play some role. Future studies should investigate the leachability of sewerage infrastructure and contributions from specific trade waste categories to determine their significance in plastics entering WWTPs.

There's something in the air: A review of sources, prevalence and behaviour of microplastics in the atmosphere.

Literature regarding microplastics in the atmosphere has advanced in recent years. However, studies have been undertaken in isolation with minimal collaboration and exploration of the relationships between air, deposition and dust. This review collates concentrations (particle count and mass-based), shape, size and polymetric characteristics for microplastics in ambient air (m3), deposition (m2/day), dust (microplastics/g) and snow (microplastics/L) from 124 peer-reviewed articles to provide a holistic overview and analysis of our current knowledge. In summary, ambient air featured concentrations between <1 to >1000 microplastics/m3 (outdoor) and <1 microplastic/m3 to 1583 ± 1181 (mean) microplastics/m3 (indoor), consisting of polyethylene terephthalate, polyethylene, polypropylene. No difference (p > 0.05) was observed between indoor and outdoor concentrations or the minimum size of microplastics (p > 0.5). Maximum microplastic sizes were larger indoors (p < 0.05). Deposition concentrations ranged between 0.5 and 1357 microplastics/m2/day (outdoor) and 475 to 19,600 microplastics/m2/day (indoor), including polyethylene, polystyrene, polypropylene, polyethylene terephthalate. Concentrations varied between indoor and outdoor deposition (p < 0.05), being more abundant indoors, potentially closer to sources/sinks. No difference was observed between the minimum or maximum reported microplastic sizes within indoor and outdoor deposition (p > 0.05). Road dust concentrations varied between 2 ± 2 and 477 microplastics/g (mean), consisting of polyvinyl chloride, polyethylene, polypropylene. Mean outdoor dust concentrations ranged from <1 microplastic/g (remote desert) to between 18 and 225 microplastics/g, comprised of polyethylene terephthalate, polyamide, polypropylene. Snow concentrations varied between 0.1 and 30,000 microplastics/L, containing polyethylene, polyamide, polypropylene. Concentrations within indoor dust varied between 10 and 67,000 microplastics/g, including polyethylene terephthalate, polyethylene, polypropylene. No difference was observed between indoor and outdoor concentrations (microplastics/g) or maximum size (p > 0.05). The minimum size of microplastics were smaller within outdoor dust (p > 0.05). Although comparability is hindered by differing sampling methods, analytical techniques, polymers investigated, spectral libraries and inconsistent terminology, this review provides a synopsis of knowledge to date regarding atmospheric microplastics.

Mass quantification of microplastic at wastewater treatment plants by pyrolysis-gas chromatography-mass spectrometry.

Municipal wastewater treatment plants (WWTPs) are a central point of collection of plastic particles from households and industry and for their re-distribution into the environment. Existing studies evaluating levels of plastics in WWTPs, and their removal rates have reported and used data on polymer type, size, shape, colour, and number of plastic particles, while the total mass concentration of plastic particles (especially >1 µm) remains unclear and unknown. To address this knowledge gap, raw influent, effluent, and reference water samples from three WWTPs in Australia were collected to analyse the mass concentrations and removal rates of seven common plastics (>1 µm in size) across the treatment schemes. Quantitative analysis was performed by pressurized liquid extraction followed by pyrolysis coupled to gas chromatography mass spectrometry. Results showed that the total plastic content in the WWTPs raw influent samples was between 840 and 3116 µg/L, resulting in an inflow of between about 2.1 and 196.4 kg/day of the total measured plastics. Overall, >99 % by mass of the plastics entering the three WWTPs from the raw influent was removed during the pre-treatment stages, presumably ending up in the sewage sludge, which means emissions (via treated effluent) from the treatment plants are low. Compared with the raw influent, the plastic mass concentrations in the treated effluents (i.e., Class C, A, and final effluent) from the three WWTPs, as well as the reference water samples within their catchments were below the limits of reporting. Of the five quantified plastic types, polyethylene (PE, 76.4 %), and polyvinylchloride (PVC, 21 %) dominated by mass, while polyethylene terephthalate (PET, 1.9 %), polypropylene (PP, 0.4 %) and polymethyl methacrylate (PMMA, 0.3 %) accounted for a small proportion of the total. Overall, this study investigated the mass concentrations of plastic particles above 1 µm in wastewater and their removal, which provided valuable information regarding the pollution level and distribution characteristics of plastic polymers in Australian WWTPs.

Identification and Quantification of Micro-Bioplastics in Environmental Samples by Pyrolysis-Gas Chromatography-Mass Spectrometry.

Bioplastics are materials that are biobased and/or biodegradable, but not necessarily both. Concerns about environmental plastic pollution are constantly growing with increasing demand for substituting fossil-based plastics with those made using renewable resource feedstocks. For many conventional bioplastics to completely decompose/degrade, they require specific environmental conditions that are rarely met in natural ecosystems, leading to rapid formation of micro-bioplastics. As global bioplastic production and consumption/use continue to increase, there is growing concern regarding the potential for environmental pollution from micro-bioplastics. However, the actual extent of their environmental occurrence and potential impacts remains unclear, and there is insufficient mass concentration-based quantitative data due to the lack of quantitative analytical methods. This study developed and validated an analytical method coupling pressurized liquid extraction and pyrolysis-gas chromatography-mass spectrometry combined with thermochemolysis to simultaneously identify and quantify five targeted micro-bioplastics (i.e., polylactic acid (PLA), polyhydroxyalkanoate, polybutylene succinate, polycaprolactone, and polybutylene adipate terephthalate (PBAT)) in environmental samples on a polymer-specific mass-based concentration. The recovery of spiked micro-bioplastics in environmental samples (biosolids) ranged from 74 to 116%. The limits of quantification for the target micro-bioplastics were between 0.02 and 0.05 mg/g. PLA and PBAT were commonly detected in wastewater, biosolids, and sediment samples at concentrations between 0.07 and 0.18 mg/g. The presented analytical method enables the accurate identification, quantification, and monitoring of micro-bioplastics in environmental samples. This study quantified five micro-bioplastic types in complex environmental samples for the first time, filling in gaps in our knowledge about bioplastic pollution and providing a useful methodology and important reference data for future research.

A novel method for the quantification of tire and polymer-modified bitumen particles in environmental samples by pyrolysis gas chromatography mass spectroscopy.

Tire and road wear particles may constitute the largest source of microplastic particles into the environment. Quantification of these particles are associated with large uncertainties which are in part due to inadequate analytical methods. New methodology is presented in this work to improve the analysis of tire and road wear particles using pyrolysis gas chromatography mass spectrometry. Pyrolysis gas chromatography mass spectrometry of styrene butadiene styrene, a component of polymer-modified bitumen used on road asphalt, produces pyrolysis products identical to those of styrene butadiene rubber and butadiene rubber, which are used in tires. The proposed method uses multiple marker compounds to measure the combined mass of these rubbers in samples and includes an improved step of calculating the amount of tire and road based on the measured rubber content and site-specific traffic data. The method provides good recoveries of 83-92% for a simple matrix (tire) and 88-104% for a complex matrix (road sediment). The validated method was applied to urban snow, road-side soil and gully-pot sediment samples. Concentrations of tire particles in these samples ranged from 0.1 to 17.7 mg/mL (snow) to 0.6-68.3 mg/g (soil/sediment). The concentration of polymer-modified bitumen ranged from 0.03 to 0.42 mg/mL (snow) to 1.3-18.1 mg/g (soil/sediment).

Phthalate esters in face masks and associated inhalation exposure risk.

This study assessed the composition of single-use face mask materials, quantified the concentration of phthalate esters in masks and evaluated associated inhalation exposure risk. All the mask samples, including 12 surgical and four N95/P1/P2 masks, were identified to be made of polypropylene, with polyethylene terephthalate present in the N95/P1/P2 masks. Di-methyl phthalate, di-n-butyl phthalate, di-ethyl phthalate, di-isobutyl phthalate and di(2-ethylhexyl) phthalate were frequently detected and their concentration summed up 55 ± 35 ~ 1700 ± 140 ng per surgical mask and 2300 ± 150 ~ 5200 ± 800 ng per N95/P1/P2 mask. Our simulation experiment suggested a mean loss of 13 - 71% of phthalate mass depending on compounds, during 5-hour wearing of these masks. This resulted in an estimated daily intake of individual compounds no higher than 20 ng/kg/day for adults and 120 ng/kg/day for toddlers, which were at least 80 times lower compared to relevant tolerable daily intake values. Two interventional trials were conducted where a volunteer wore a mask for four hours and urine samples were collected before and after the mask wearing. No obvious increase was observed for the urinary concentration of any phthalate metabolite, indicating minimal contribution to overall exposure to phthalate esters.

Does size matter? Quantification of plastics associated with size fractionated biosolids.

This study investigated the occurrence and contribution of plastic particles associated with size fractionated biosolids to the total concentration in biosolids (treated sewage sludge) samples collected from 20 wastewater treatment plants (WWTP) across Australia. This was achieved through sequential size fractionation of biosolids samples to quantify the mass concentration of 7 common plastics across a range of biosolids size fractions, including below 25 µm which has not been assessed in many previous studies. Quantitative analysis was performed by pressurized liquid extraction followed by pyrolysis coupled to gas chromatography - mass spectrometry. Of the total quantified plastics (Σ7plastics), the greatest proportion (27%) of the total mass were identified in the nominal <25 µm sized biosolids fraction. Polyethylene dominated the polymer mass in every size fraction, even though profiles varied between WWTPs. When comparing the sum of all sites for each sized biosolids fraction, the plurality of the polyethylene, polyvinyl-chloride, polystyrene, polypropylene, polycarbonate, and polyethylene-terephthalate concentrations were associated with the smallest size fraction (<25 µm). We confirm for the first time the presence of plastic particles in biosolids below a size fraction that is not captured by many methods. This is important, because of the potential greater significance of plastics in the low sizes to environmental and human health.

Influence of surface oxidation on the quantification of polypropylene microplastics by pyrolysis gas chromatography mass spectrometry.

The influence of photo-oxidation on the quantification of isotactic polypropylene by Pyrolysis Gas Chromatography/Mass Spectrometry (Pyr-GC/MS) was assessed. Beads (oval shape, ~5 mm) and fragments (irregular shaped, 250-50 µm and 500-1000 µm) were subjected to relatively harsh simulated accelerated weathering conditions (using a filtered xenon-arc reproducing sunlight's full spectrum) for up to 37 and 80 days, respectively. Samples collected (n = 10 replicates for each treatment) at increasing number of weathering days were analysed by Fourier-transform infrared spectroscopy with Attenuated Total Reflection (FTIR-ATR), scanning electron microscopy, and differential scanning calorimetry in order to assess the extent and the rate of degradation. The rate of surface oxidation occurred faster for fragments compared to beads, probably due to their higher surface area. Quantification of the polypropylene trimer (2,4-dimethyl-1-heptene) via double shot Pyr-GC/MS, showed that the signal of the trimer relative to the mass of polypropylene was reduced through weathering with a degradation rate of 1:3 faster for fragments over beads. Signal reduction and carbonyl index were correlated to show that polypropylene with a carbonyl index of ≥13 has a significantly reduced 2,4-dimethyl-1-heptene signal when compared to virgin material. Consequently, the quantification of polypropylene subjected to weathering under harsh conditions may be underestimated by 42% (fragments, carbonyl index: 18) to 49% (beads, carbonyl index: 30) when quantified by Pyr-GC/MS and using virgin polypropylene calibration standards. Pyrolysis at a lower temperature (350 °C) identified six degradation specific markers (oxidation products) that increased in concentration with weathering. Further comparisons between virgin and weathered microplastics may need to be considered to avoid underestimation of microplastic concentrations in future studies.

Plastics contamination of store-bought rice.

This study investigated mass concentrations of selected plastics in store-bought rice, the staple of more than half the world's population. Polyethylene, polyethylene terephthalate, poly-(methyl methacrylate), polypropylene, polystyrene and polyvinyl chloride were quantified using pressurized liquid extraction coupled to double-shot pyrolysis gas chromatography/mass spectrometry. Polyethylene, polypropylene and polyethylene terephthalate were quantifiable in the rice samples with polyethylene the most frequently detected (95%). There was no statistical difference between total plastic concentration in paper and plastic packaged rice. Shaking the rice in its packaging had no significant difference on the concentration of plastics. Washing the rice with water significantly reduced plastic contamination. Instant (pre-cooked) rice contained fourfold higher levels of plastics, suggesting that industrial processing potentially increases contamination. A preliminary estimate of the intake of plastic through rice consumption for Australians established 3.7 mg per serve (100 g) if not washed and 2.8 mg if washed. Annual consumption was estimated around 1 g/person.

Microparticles and microplastics contamination in African table salts.

The presence of micro/plastic particles has been reported in various seafood products. However, information on microplastics contamination in salts from African continent is very limited. This study analysed 23 brands of table salts from 8 African countries for microplastics using microscopic/spectroscopic techniques. South Africa showed the highest microplastics concentration (0-1.33 ± 0.32 particles/kg), Nigeria, Cameroun, and Ghana (0-0.33 ± 0.38 particles/kg each); characterized as polyvinyl acetate, polypropylene, and polyethylene. Other countries have no detectable microplastics at 0.3 µm filter pore size. To our best knowledge, this is the first study to characterize micro-fibres/plastics in table salts across African countries, confirming that it is an emission source of micro-fibres/plastics into the human food chain, highlighting the overarching need to understand their effects on human health.

Microplastics in African ecosystems: Current knowledge, abundance, associated contaminants, techniques, and research needs.

Despite Africa ranking top in mismanaged plastic waste, there is insufficient data on the extent of microplastics and its interaction with other contaminants in its ecosystems. Microplastics pollution has been documented globally, however, specific data from the continent is crucial for accurate risk assessment and to drive policies. We critically reviewed 56 articles from 1987 to 2020 and provide an overview of the current knowledge of the abundance and distribution of microplastics and associated contaminants in African aquatic systems and organisms. Most of the studies were carried out in the marine environment and there is currently no available data on the abundance of microplastic pollution in the African terrestrial environment. We show that across all studies, 5-100% of all sampled aquatic organisms contained microplastics. Concerning high levels of microplastics were reported in fish from Egypt compared to other parts of Africa and the world. Across all persistent organic pollutants sampled in microplastics, hopanes and phthalates were present at high concentrations while sodium and zinc were high relative to other trace metals reported. The most frequently occurring plastics were polyethylene followed by polypropylene and polystyrene. We found that most of the studies relied on visual inspection (52%) > FTIR (38%) > Raman spectroscopy (5%) > Scanning electron microscopy (3%) > Differential scanning calorimetry (2%) for identifying microplastics. Major gaps in sampling and identification techniques which may have overestimated or underestimated the current levels were identified. We discuss other research priorities and recommend solutions to address these issues associated with microplastic pollution in Africa.

Quantitative Analysis of Selected Plastics in High-Commercial-Value Australian Seafood by Pyrolysis Gas Chromatography Mass Spectrometry.

Microplastic contamination of the marine environment is widespread, but the extent to which the marine food web is contaminated is not yet known. The aims of this study were to go beyond visual identification techniques and develop and apply a simple seafood sample cleanup, extraction, and quantitative analysis method using pyrolysis gas chromatography mass spectrometry to improve the detection of plastic contamination. This method allows the identification and quantification of polystyrene, polyethylene, polyvinyl chloride, polypropylene, and poly(methyl methacrylate) in the edible portion of five different seafood organisms: oysters, prawns, squid, crabs, and sardines. Polyvinyl chloride was detected in all samples and polyethylene at the highest total concentration of between 0.04 and 2.4 mg g-1 of tissue. Sardines contained the highest total plastic mass concentration (0.3 mg g-1 tissue) and squid the lowest (0.04 mg g-1 tissue). Our findings show that the total concentration of plastics is highly variable among species and that microplastic concentration differs between organisms of the same species. The sources of microplastic exposure, such as packaging and handling with consequent transference and adherence to the tissues, are discussed. This method is a major development in the standardization of plastic quantification techniques used in seafood.

Identification and quantification of selected plastics in biosolids by pressurized liquid extraction combined with double-shot pyrolysis gas chromatography-mass spectrometry.

The identification and quantification of selected plastics (polystyrene (PS), polycarbonate (PC), poly-(methyl methacrylate) (PMMA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE) and polyvinyl chloride (PVC)) in biosolids (treated sewage sludge) was performed by pressurized liquid extraction (PLE) combined with double-shot pyrolysis gas chromatography-mass spectrometry. Validation of the method yielded recoveries of between 85 and 128% (mean RSD 11%) at a linear range of between 0.01 and 2 µg. The distribution of plastics within 25 biosolid samples from a single wastewater treatment plant in Australia was assessed. The mass concentration of PE, PVC, PP, PS and PMMA was between 0.1 and 4.1 mg/g dry weight (dw) across all samples, with a total plastic concentration Æ©Plastics of between 2.8 and 6.6 mg/g dw (median = 4.1 mg/g dw). PE was the predominant plastic detected (mean concentration of 2.2 mg/g dw), contributing to 50% of the total of all plastics. Overall, this study demonstrates that pressurized liquid extraction (PLE) combined with double-shot pyrolysis gas chromatography-mass spectrometry can be used to identify and quantify PE, PP, PVC, PS, and PMMA in biosolids.