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

Abstract

Sunlight transforms plastic into water-soluble products, the potential toxicity of which remains unresolved, particularly for vertebrate animals. We evaluated acute toxicity and gene expression in developing zebrafish larvae after 5 days of exposure to photoproduced (P) and dark (D) leachates from additive-free polyethylene (PE) film and consumer-grade, additive-containing, conventional, and recycled PE bags. Using a "worst-case" scenario, with plastic concentrations exceeding those found in natural waters, we observed no acute toxicity. However, at the molecular level, RNA sequencing revealed differences in the number of differentially expressed genes (DEGs) for each leachate treatment: thousands of genes (5442 P, 577 D) for the additive-free film, tens of genes for the additive-containing conventional bag (14 P, 7 D), and none for the additive-containing recycled bag. Gene ontology enrichment analyses suggested that the additivefree PE leachates disrupted neuromuscular processes via biophysical signaling; this was most pronounced for the photoproduced leachates. We suggest that the fewer DEGs elicited by the leachates from conventional PE bags (and none from recycled bags) could be due to differences in photoproduced leachate composition caused by titanium dioxide-catalyzed reactions not present in the additive-free PE. This work demonstrates that the potential toxicity of plastic photoproducts can be product formulation-specific.

Minimizing the Environmental Impacts of Plastic Pollution through Ecodesign of Products with Low Environmental Persistence

“…This poses challenges in knowing whether k d represents the chemical degradation (depolymerization) of the polymer or merely the physical degradation (disintegration) to microplastics. Future research should prioritize the relative importance and controls of plastic degradation processes and products, as well as the environmental impacts (e.g., ecotoxicity) of any degradation products and leachable compounds released from plastics into the environment. , …”

“…Future research should prioritize the relative importance and controls of plastic degradation processes and products, as well as the environmental impacts (e.g., ecotoxicity) of any degradation products and leachable compounds released from plastics into the environment. 76 , 77 …”

Moldable Plastics (Polycaprolactone) can be Acutely Toxic to Developing Zebrafish and Activate Nuclear Receptors in Mammalian Cells

“…Despite the LC 50 for consumer-grade PCL (30 mg/mL) being well above the concentration of plastic found in natural waters (∼10s ng/L to ∼100s mg/L; <100 particles/L), the acute toxicity of PCL raises concern. This is because any mortality of zebrafish embryos from exposure to relatively large pieces of plastic compared to the size of the embryos is rare.…”

“…Zebrafish are a widely used model organism in chemical and material toxicology because of their rapid development, ease of use, and well-documented phenotypes and responses to chemical toxicants (e.g., polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and bisphenol A). , Additionally, fish embryos can be more susceptible to toxicants during early development, thus providing greater sensitivity to the effects of any leached chemicals from the moldable plastic. Exposure to plastics and their associated chemicals has often resulted in sublethal effects reflected by changes in gene expression, metabolic activity, and behavior. − Only in a few instances have plastic items been acutely toxic to zebrafish embryos. In these cases, toxicity has been attributed to the release of a residual, nonintentionally added substance (e.g., acrylate monomer or surfactant). , …”

Identification of Additives in Disposable Face Masks and Evaluation of Their Toxicity Using Marine Medaka (Oryzias melastigma)

“…The additives in the face masks can be leached out once they are in the ocean, posing a potential hazard to marine organisms. , Previous studies have demonstrated that plastic additives can cause various adverse effects on the development, nerve, and endocrine system in aquatic animals. − In addition, mask fragments can downregulate the transcription of target genes related to reproduction in zebrafish, cause histopathological alterations of the liver, gills, and intestine of zebrafish, and disrupt their aggressive behavior . However, research on the toxicity of face masks, particularly their additives, to marine organisms is extremely scarce.…”