Publications by year
Burrows S, Olive R, O'Brien S, Galloway T (2022). Connection is key when there's no planet B: the need to innovate environmental science communication with transdisciplinary approaches. Science of the Total Environment, 853, 158435-158435.
Okoffo ED, O'Brien S, O'Brien JW, Tscharke BJ, Rauert C, Rødland ES, Ribeiro F, Burrows SD, Toapanta T, Mueller JF, et al
(2022). Does size matter? Quantification of plastics associated with size fractionated biosolids. Sci Total Environ
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 Abstract
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Burrows SD, Ribeiro F, O'Brien S, Okoffo E, Toapanta T, Charlton N, Kaserzon S, Lin CY, Tang C, Rauert C, et al
(2022). The message on the bottle: Rethinking plastic labelling to better encourage sustainable use. Environmental Science and Policy
The message on the bottle: Rethinking plastic labelling to better encourage sustainable use
Plastic pollution continues to worsen globally in volume and complexity. The complexity in plastic production, use and disposal is significant, highlighting the importance of clear communication to consumers. Yet despite this, poor plastic labelling is clear, evident from poor waste management metrics even in the most equipped countries. Plastic labelling must change to contribute to a holistic intervention on global plastic mismanagement. Discussion on this topic leads to three key recommendations: 1. An accurate and clear “sustainability scale” to empower consumers to make decisions informed by environmental and human health implications; 2. Directions for appropriate disposal action in the region of purchase; 3. A comprehensive list of plastic composition, including additives. Abstract
Toapanta T, Okoffo ED, Ede S, O'Brien S, Burrows SD, Ribeiro F, Gallen M, Colwell J, Whittaker AK, Kaserzon S, et al
(2021). Influence of surface oxidation on the quantification of polypropylene microplastics by pyrolysis gas chromatography mass spectrometry. Sci Total Environ
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. Abstract
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Okoffo ED, O'Brien S, Ribeiro F, Burrows SD, Toapanta T, Rauert C, O'Brien JW, Tscharke BJ, Wang X, Thomas KV, et al
(2021). Plastic particles in soil: state of the knowledge on sources, occurrence and distribution, analytical methods and ecological impacts. Environmental Science: Processes & Impacts
Plastic particles in soil: state of the knowledge on sources, occurrence and distribution, analytical methods and ecological impacts
Increased production and use of plastics has resulted in growth in the amount of plastic debris accumulating in the environment, potentially fragmenting into smaller pieces. Abstract
Okoffo ED, Donner E, McGrath SP, Tscharke BJ, O'Brien JW, O'Brien S, Ribeiro F, Burrows SD, Toapanta T, Rauert C, et al
(2021). Plastics in biosolids from 1950 to 2016: a function of global plastic production and consumption. Water Res
Plastics in biosolids from 1950 to 2016: a function of global plastic production and consumption.
Plastics are ubiquitous contaminants that leak into the environment from multiple pathways including the use of treated sewage sludge (biosolids). Seven common plastics (polymers) were quantified in the solid fraction of archived biosolids samples from Australia and the United Kingdom from between 1950 and 2016. Six plastics were detected, with increasing concentrations observed over time for each plastic. Biosolids plastic concentrations correlated with plastic production estimates, implying a potential link between plastics production, consumption and leakage into the environment. Prior to the 1990s, the leakage of plastics into biosolids was limited except for polystyrene. Increased leakage was observed from the 1990s onwards; potentially driven by increased consumption of polyethylene, polyethylene terephthalate and polyvinyl chloride. We show that looking back in time along specific plastic pollution pathways may help unravel the potential sources of plastics leakage into the environment and provide quantitative evidence to support the development of source control interventions or regulations. Abstract
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O'Brien S, Okoffo ED, Rauert C, O'Brien JW, Ribeiro F, Burrows SD, Toapanta T, Wang X, Thomas KV
(2021). Quantification of selected microplastics in Australian urban road dust. J Hazard Mater
Quantification of selected microplastics in Australian urban road dust.
Microplastics (1 - 5000 µm) are pervasive in every compartment of our environment. However, little is understood regarding the concentration and size distribution of microplastics in road dust, and how they change in relation to human activity. Within road dust, microplastics move through the environment via atmospheric transportation and stormwater run-off into waterways. Human exposure pathways to road dust include dermal contact, inhalation and ingestion. In this study, road dust along an urban to rural transect within South-East Queensland, Australia was analysed using Accelerated Solvent Extraction followed by pyrolysis Gas Chromatography-Mass Spectrometry (Pyr-GC/MS). Polypropylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, poly (methyl methacrylate) and polyethylene were quantified. Microplastic concentrations ranged from ~0.5 mg/g (rural site) to 6 mg/g (Brisbane city), consisting primarily of polyvinyl chloride (29%) and polyethylene terephthalate (29%). Size fractionation ( Abstract
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Burrows SD, Frustaci S, Thomas KV, Galloway T
(2020). Expanding exploration of dynamic microplastic surface characteristics and interactions. TrAC - Trends in Analytical Chemistry
Expanding exploration of dynamic microplastic surface characteristics and interactions
Microplastics have been found in all marine ecosystems, raising concern about their potential environmental impacts. Yet relatively little research has focused on surface characteristics, compared to polymer type. The aim of this review is to discuss the importance of microplastic surface properties and how expanded characterisation and more detailed quantification can aid in assessing their behaviours in aquatic environments. Concepts including surface roughness, formation of surface ecocoronae and sorptive behaviours of microplastic surfaces are discussed. To address these concepts, three exemplary methods are introduced and their application to the study of microplastic surfaces discussed with the following recommendations; atomic force microscopy should be explored for conducting physical surface characterisation and to examine surface roughness; double-shot Pyrolysis-Gas Chromatography–Mass Spectroscopy should be considered for examining microplastic sorption behaviours in multi-solute media; and finally, Whispering Gallery Mode nanosensing techniques should be explored as a potential means to generate data on microplastic sorption kinetics. Abstract
Okoffo ED, Tscharke BJ, O'Brien JW, O'Brien S, Ribeiro F, Burrows SD, Choi PM, Wang X, Mueller JF, Thomas KV, et al
(2020). Release of Plastics to Australian Land from Biosolids End-Use. Environ Sci Technol
Release of Plastics to Australian Land from Biosolids End-Use.
Plastics are contaminants of emerging concern that can enter the environment from multiple sources, including via land application of treated sewage sludge (biosolids). Biosolids samples collected from 82 wastewater treatment plants (WWTPs) across Australia and covering 34% of the population during census week in 2016 were quantitatively analyzed to estimate the release of seven common plastics. Quantitative analysis was performed by pressurized liquid extraction followed by double-shot microfurnace pyrolysis coupled to gas chromatography mass spectrometry. Ninety nine percent of the samples contained plastics (Σ6plastics) at concentrations of between 0.4 and 23.5 mg/g dry weight (median; 10.4 mg/g dry weight), while polycarbonate was not detected in any sample. Per-capita mass loads of plastics (Σ6plastics) released were between 8 and 877 g/person/year across all investigated WWTPs. Polyethylene was the predominant plastic detected, contributing to 69% of Σ6plastics. Based on the concentrations measured, it was projected that around 4700 metric tons (Mt) of plastics are released into the Australian environment through biosolids end-use each year, equating to approximately 200 g/person/year, which represents 0.13% of total plastics use in Australia. of this, 3700 Mt of plastics are released to agricultural lands and 140 Mt to landscape topsoil. Our results provide a first quantitative per-capita mass loads and emission estimate of plastic types through biosolids end-use. Abstract
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