A Production and Fractionation Protocol for Polyvinyl Chloride Microplastics.

Concerns about the presence of microplastics in the environment has increased in recent years, prompting more attention from scientists. Thorough exposure studies using artificially produced microplastics containing additives are required to assess their potentially hazardous effects. Therefore, an efficient microplastic production and fractionation protocol was established using a cryogenic grinding and wet-sieving approach. The developed cryogenic grinding method was able to produce (20-40 g/h) polyvinyl chloride (PVC) microplastics having a volume-weighted mean particle size of 391 µm and a span of 2.12. Performing a second grinding cycle on the same particles resulted in microplastics which were smaller (volume-weighted mean size = 219 µm) and had a narrower particle size distribution (span = 1.59). In addition, the microplastics were also fractionated into different particle size ranges using a vibrating wet-sieving tower. The latter technique allowed separating 10 g of PVC microplastics into seven different fractions using six sieves (Ø 200 mm) for 30 min while shaking. By using the developed method, PVC microplastics could easily be made and fractionated into desired particle-size ranges. The proposed protocol could also be adjusted to produce and fractionate microplastics of other plastics.

Ingestion and excretion dynamics of microplastics by black soldier fly larvae and correlation with mouth opening size.

Black soldier fly (BSF) larvae (Hermetia illucens) are voracious feeders that can be reared on food waste streams originating from the food industry and retailers. Because these food waste streams are automatically being unpacked in substantial amounts, they can contain microplastics, potentially jeopardising the larvae's chemical safety when applied as compound feed ingredients. During this study, the dynamics of ingestion and excretion of microplastics by BSF larvae reared on substrates containing different contents (wMP = 0.00, 0.01, 0.10, 0.50, 1.00, 3.00%) of fluorescent blue-labelled microplastics (median size, Dv(50) = 61.5 µm) were monitored. To correlate the particle size with their uptake, larval mouth opening dimensions were measured during the rearing process. In conclusion, it appeared that ingestion of microplastics by BSF larvae depends on initial particle load, mouth size, and consequently also age. The larvae took up between 131 (wMP = 0.01%) and 4866 (wMP = 3.00%) particles leading to bioaccumulation factors (BAF) between 0.12 (wMP = 3.00%) and 1.07 (wMP = 0.01%). Larvae also appeared to excrete the microplastics, lowering the BAFs to values between 0.01 (wMP = 3.00%) and 0.54 (wMP = 0.01%).

Characterizing Mechanical, Heat Seal, and Gas Barrier Performance of Biodegradable Films to Determine Food Packaging Applications.

In an organic circular economy, biodegradable materials can be used as food packaging, and at end-of-life their carbon atoms can be recovered for soil enrichment after composting, so that new food or materials can be produced. Packaging functionality, such as mechanical, gas barrier, and heat-seal performance, of emerging biodegradable packaging, with a laminated, coated, monomaterial, and/or blended structure, is not yet well known in the food industry. This lack of knowledge, in addition to end-of-life concerns, high cost, and production limits is one of the main bottlenecks for broad implementation in the food industry. This study determines application areas of 10 films with a pragmatic approach based on an experimental broad characterization of packaging functionality. As a conclusion, the potential application of these materials is discussed with respect to industrial settings and food and consumer requirements, to support the implementation of commercially available, biodegradable, and, more specifically, compostable, materials for the identified food applications.