Search

Expanded polystyrene (EPS) plastic is widely used because of its low density and lightweight properties, enabling it to float on water and increase its exposure to sunlight. In this study, we simulated the photoaging process of flame retardant-added EPS (FR-EPS) and common original EPS (OR-EPS) microplastic (MP) particles with and without methyl octabromoether flame retardant (MOBE) in the laboratory to explore the effect of MOBE on the photodegradation of EPS. Results showed that MOBE accelerated size reduction and surface hole formation on the particles, hastening the shedding and replacement of particle surfaces. FR-EPS particles exhibited a weight loss exceeding that of OR-EPS, reaching 40.85 ± 3.72% after 36 days of irradiation. Moreover, rapid physical peeling of the FR-EPS surface was accompanied by continuous chemical oxidation and fluctuations of the carbonyl index and O/C ratio. A diffusion model based on Fick's second law fitted well for the concentration of MOBE remaining in FR-EPS particles. MOBE's sensitivity to direct photochemical reactions inhibited the early-stage photoaging of EPS MP particles by competing for photons. However, MOBE as chromophores could absorb photons and produce •OH to promote the aging of EPS. Moreover, the capacity of EPS to absorb light energy also accelerated MOBE degradation. These findings suggested that the photoaging behavior of commercial EPS products containing flame retardants in the environment is quite different from that of pure EPS, indicating that additive-plastic interactions significantly alter MP fate and environmental risks. [Display omitted] • Surface spalling was the main pathway of particle fragmentation. • FR-EPS exhibited a greater weight loss than OR-EPS after long-term UV irradiation. • The fluctuation of the oxidation degree of EPS resulted from the surface spalling. • Photoaged EPS MPs had a positive interaction on the photolysis of MOBE. [ABSTRACT FROM AUTHOR]

Expanded polystyrene (EPS) pollution in the marine environment is a pressing issue in Queensland, Australia due to a recent flood that scattered hundreds of EPS-containing pontoons along the coastline, causing severe ecological damage. To assist in the clean-up effort and provide crucial data for developing management guidelines, this study investigates the environmental performance of different end-of-life (EoL) disposal/recycling methods, including (i) landfill; (ii) on-site mechanical re-processing using a thermal densifier (MR); and (iii) on-site dissolution/precipitation using d -limonene (DP). Applying the life cycle assessment framework, the results showed that DP was the most environmentally favourable option. Its impacts in climate change (GWP), acidification (TAP), and fossil fuel depletion (FFD) were 612 kg CO 2 eq, 4.3 kg SO 2 eq, and 184.7 kg oil eq, respectively. For comparison, the impacts of landfilling EPS in these categories were found to be 700 kg CO 2 eq, 3.5 kg SO 2 eq, and 282 kg oil eq, respectively. Landfill also contributed considerably to eutrophication potential (MEP), at 3.77 kg N eq. Impacts from MR were most significant due to the need to transport the densifier unit to the site. The analysis also revealed that the transportation of personnel and heavy machinery to the site, was the biggest contributor to impacts in the EoL stage. Its impacts in GWP, TAP, MEP, and FFD were 1369.8 kg CO 2 eq, 6.5 kg SO 2 eq, 0.2189 kg N eq, and 497.7 kg oil eq, respectively. Monte Carlo analysis showed that the conclusions made from these results were stable and reliable. Limitations of this model and recommendations for future investigations were also discussed in this work. [Display omitted] • Transportation imposed the highest impacts during disposal of missing pontoons. • Mechanical re-processing had highest impacts. • d -limonene dissolution showed the best environmental performance. • Further research is needed to optimise d -limonene dissolution process. • Recovery of PS is desirable, but not feasible. [ABSTRACT FROM AUTHOR]

Expanded polystyrene (EPS) is a major component of marine debris globally. Recently, hazardous hexabromocyclododecanes (HBCDDs) were detected in EPS buoys used for aquaculture farming. Subsequently, enrichment of HBCDDs was found in nearby marine sediments and mussels growing on EPS buoys. It was suspected that EPS buoys and their debris might be sources of HBCDDs. To confirm this, the release of HBCDDs from EPS spherules detached from a buoy to seawater was investigated under field (open sea surface and closed outdoor chambers with sun exposure and in the dark) and laboratory (particle-size) conditions. In all exposure groups, initial rapid leaching of HBCDDs was followed by slow desorption over time. Abundant release of HBCDDs was observed from EPS spherules exposed to the open sea surface (natural) and on exposure to sunlight irradiation or in the dark in controlled saline water. Water leaching and UV-light/temperature along with possibly biodegradation were responsible for about 37% and 12% of HBCDDs flux, respectively. Crumbled EPS particles (≤1 mm) in samples deployed on the sea surface for 6 months showed a high degree of weathering. This implies that surface erosion and further fragmentation of EPS via environmental weathering could enhance the leaching of HBCDDs from the surface of EPS. Overall, in the marine environment, HBCDDs could be released to a great extent from EPS products and their debris due to the cumulative effects of the movement of large volumes of water (dilution), biodegradation, UV-light/temperature, wave action (shaking), salinity and further fragmentation of EPS spherules. [ABSTRACT FROM AUTHOR]

Yellow mealworms (Tenebrio molitor larvae) are capable of biodegrading polystyrene (PS) and low-density polyethylene (LDPE). This study tested biodegradation of one expanded PS (EPS) with a weight-average molecular weight (M w) 256.4 kDa and two LDPE foams with respective M w of 130.6 kDa (PE-1) and 288.7 kDa (PE-2) in T. monitor larvae obtained in Beijing, China. The larvae consumed EPS and both LDPEs over a 60 day. Fourier transform infrared spectroscopy and thermogravimetric analyses of frass confirmed the formation of new oxygen-containing functional groups, as well as a change in physical property and chemical modification, indicating that biodegradation of EPS and LDPE occurred. Gel permeation chromatography analysis confirmed broad depolymerization of EPS and PE-1 (i.e., a decrease in both M w and a number-average molecular weight (M n)) but revealed limited extent depolymerization of PE-2 (i.e. , increase in M n and decrease in M w). For all materials, the size-average molecular weight (M z) was decreased. Biodegradation and oxidation of EPS and LDPE were confirmed using FTIR and TGA analysis. Depression of gut microbes by the antibiotic gentamicin resulted in significant inhibition of EPS depolymerization but did not stop LDPE depolymerization, resulting in the increase in M n and revealing that PS biodegradation was gut microbe-dependent but LDPE biodegradation was less dependent or independent of gut microbes. Gut microbial community analysis indicated that, as expected, under different dietary conditions, the intestinal flora significantly shifted to communities associated with biodegradation of EPS and LDPE. The results indicated the complexity and limitation of biodegradation of plastics in plastics-eating T. molitor larvae. Image 1 • Biodegradation of PS and two LDPE with decreased M z by Tenebrio molitor larvae. • Broad depolymerization of PS and one LDPE with decreased both M w and M n. • Limited extent depolymerization of LDPE with decreased M w but increased M n. • The antibiotic gentamicin inhibited depolymerization of PS but not LDPE. • Distinct microbiomes observed with three different diets bran, PS, and LDPE. [ABSTRACT FROM AUTHOR]

As expanded polystyrene (EPS) has been utilized in soil environments, there is a need to understand interactions between chemical adsorption and the soil system. We conducted a plant bioassay using agricultural crops in a soil system containing a macro-sized EPS (8.3 ± 0.5 mm). When the EPS was collected after cultivation of no crop (control), mung bean, lettuce, and rice, we found that its water absorption rate significantly (p < 0.05) increased after mung bean and rice cultivation as compared to the no crop condition. We expected that these crop-dependent differences would be highly linked with metal adsorption and desorption. However, cadmium (Cd) adsorption percentages (%) from the initial Cd solution were calculated as 15-18% with no significant differences between the different crop cultivation conditions. The desorption percentages also showed low levels of interaction with the crop-dependent water absorption rate. These results provide useful data for better understanding the interaction between plastics and their roles as chemical vectors in the soil system., (Copyright © 2018 Elsevier Ltd. All rights reserved.)