Role of UV radiation and oxidation on polyethylene micro- and nanoplastics: impacts on cadmium sorption, bioaccumulation, and toxicity in fish intestinal cells

• Published in: Environmental science and pollution research international 2024-07, Vol.31 (35), p.47974-47990
• Main Authors: Pinto, Estefanía Pereira, Scott, Justin, Hess, Kendra, Paredes, Estefanía, Bellas, Juan, Gonzalez-Estrella, Jorge, Minghetti, Matteo
• Format: Article
• Language: English
• Subjects: Animals; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bioaccumulation; Bioavailability; Cadmium; Cadmium - toxicity; Cell size; Coated particles; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Exposure; Fourier transforms; High density polyethylenes; Infrared radiation; Infrared spectroscopy; Intestine; Intestines - drug effects; Light scattering; Microplastics; Microplastics - toxicity; Oncorhynchus mykiss; Oxidation; Oxidation-Reduction; Photon correlation spectroscopy; Plastic pollution; Polyethylene; Polyethylene - chemistry; Polyethylene - toxicity; Proteins; Research Article; Salmon; Toxicity; Trout; Ultraviolet radiation; Ultraviolet Rays; Waste Water Technology; Water Management; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Water Pollution Control; Zeta potential
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-024-34301-x

This study investigated the role of ultraviolet (UV) radiation and oxidation in high-density polyethylene microplastics (2–15 μm) and nanoplastics (0.2–9.9 μm) (NMPs) on particle chemistry, morphology, and reactivity with cadmium (Cd). Additionally, toxicity of NMPs alone and with Cd was evaluated using RTgutGC cells, a model of the rainbow trout ( Oncorhynchus mykiss ) intestine. The role on NMPs on Cd bioaccumulation in RTgutGC cells was also evaluated. Dynamic light scattering indicated that after UV radiation NPs agglomerated size increased from 0.8 to 28 µm, and to 8 µm when Cd was added. Oxidized MPs agglomerated size increased from 11 and 7 to 46 and 27 µm in non-UV- and UV-aged oxidized MPs when adding Cd, respectively. Cd-coated particles exhibited generally significantly higher zeta potential than non-Cd-coated particles, while attenuated total reflectance–Fourier transform infrared spectroscopy showed that the functional chemistry of the particles was oxidized and modified after being exposed to UV radiation. Presence of NMPs resulted in a significant decrease in Cd bioaccumulation in RTgutGC cells (100.5–87.9 ng Cd/mg protein) compared to Cd alone (138.1 ng Cd/mg protein), although this was not quite significant for co-exposures with UV-aged NPs (105.7 ng Cd/mg protein). No toxicity was observed in RTgutGC cells exposed to NMPs alone for 24 h. Moreover, co-exposures with Cd indicated that NMPs reduce the toxicity of Cd. Altogether these results show that UV aging enhances NMP surface reactivity, increasing Cd absorption in solution, which resulted in a reduction in Cd bioavailability and toxicity.