Photochemical weathering of polyurethane microplastics produced complex and dynamic mixtures of dissolved organic chemicals

Abstract

Sunlight exposure can naturally mitigate microplastics pollution in the surface ocean, however it results in emissions of dissolved organic carbon (DOC) whose characteristics and fate remain largely unknown. In this...

Tracking Dynamic Chemical Reactivity Networks with High-Resolution Mass Spectrometry: A Case of Microplastic-Derived Dissolved Organic Carbon

“…The microplastics were photoweathered in a custom-built reactor previously described by Albergamo et al and upgraded as detailed in the SI (Section S3). Briefly, the peak emission at the center of the reactor was 60 μW cm –2 nm –1 at 340 nm, aligning well with current standards for ultraviolet spectral distribution . After 14, 21, and 28 days in the reactor, the cumulative UV dose values integrated over the 300–400 nm range were 940, 1410, and 1880 MJ m –2 , respectively.…”

Formulation Controls the Potential Neuromuscular Toxicity of Polyethylene Photoproducts in Developing Zebrafish

“…An unresolved question is whether the transformation products from inorganic additive-containing consumer plastics generated by weathering processes are toxic to organisms exposed to them . Photochemical degradation is the primary source of thousands of transformation products released from plastics into the environment. − Recent in vitro (using cell-based reporter assays − ) and limited but growing collection of in vivo studies − indicate that exposure to photochemical transformation products can lead to adverse biological effects. For example, photoproducts from additive-free polyethylene (PE) showed greater biological activity than additive-free polypropylene, polyethylene terephthalate, and polystyrene, , which was attributed, in part, to the formation of mono- and dicarboxylic acids. ,, A key limitation of many of these initial studies is that they focused on the transformation of additive-free plastics or uncommon marine plastic debris (e.g., keyboards) that do not accurately reflect the much broader diversity of plastic product formulations. ,, Several studies have recently demonstrated that the formulation of plastics (i.e., the combination of polymer and additives) substantially influences the rates and chemical composition of resultant photoproducts. ,,,, For example, titanium dioxide (TiO 2 ) inorganic additives, used as white pigments in single-use PE bags, promoted photochemical degradation and resulted in unique photoproduct compositions, forming a complex mixture of tens of thousands of compounds .…”

Ranking the accelerated weathering of plastic polymers

“…10 Photodegradation is typically the most important pathway, at least in the presence of sunlight. 5,18–21 It acts to weaken and embrittle plastic litter and typically precedes and fragmentation by mechanical forces, e.g. , abrasion with sand or rocks, wave action and swelling–deswelling, and eventually biodegradation.…”

“…10 Photodegradation is typically the most important pathway, at least in the presence of sunlight. 5,[18][19][20][21] It acts to weaken and embrittle plastic litter and typically precedes and fragmentation by mechanical forces, e.g., abrasion with sand or rocks, wave action and swelling-deswelling, and eventually biodegradation. 5,7,8,22 Conversely, in certain environmental compartments, for example, subtropical saltmarshes where biolm formation limits transmittance of sunlight, biodegradation and mechanical abrasion can be more prevalent than photodegradation.…”