We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Response of microplastic color to photoaging and its influence on the release characteristics of derived dissolved organic matters
Summary
Researchers investigated how the color of microplastics affects their degradation under sunlight and the release of dissolved organic matter. The study found that red and yellow microplastics degraded faster due to stronger ultraviolet absorption, releasing more dissolved organic matter, and that long-term exposure to degradation byproducts from certain colored microplastics inhibited plant seed germination and antioxidant enzyme activity.
This study systematically investigated the regulatory mechanisms of color parameters on the photoaging behavior and ecological effects of polypropylene (PP) and polymethylmethacrylate (PMMA). We revealed the evolution of the physicochemical properties of various colored microplastics. These results indicate that red and yellow microplastics significantly accelerated surface oxidation and chain breakage due to their strong ultraviolet absorption properties (long wavelength of 380-420 nm). This led to an increase in specific surface area, exemplified by a 10.8% increase in the crystallinity of red PP, an enhancement in surface roughness characterized by dense cracks on the surface of red PMMA, and a greater release of dissolved organic matter (MPs-DOM). DOM components exhibited color dependence, with the red group displaying the highest peak fluorescence intensity. PMMA was primarily composed of humic acids (Ex/Im = 240-250/420-425 nm), while PP released polycyclic aromatic hydrocarbons (Ex/Im = 220-225/305-310 nm). Biological toxicity experiments demonstrated that PMMA-DOM aged for 30 days significantly inhibited the germination rate of Chinese cabbage seeds, averaging 92%. Red PP-DOM promoted a 22.7% increase in seed wet weight during the early stage (10 d). However, long-term exposure (90 days) inhibited the activities of superoxide dismutase (SOD) and catalase (CAT) due to the accumulation of free radicals. Further research has shown that green microplastics exhibit weaker light absorption capabilities and lower toxicity effects related to DOM. This study elucidates the mechanism by which color influences the environmental fate of microplastics through their photoresponsive properties, providing a theoretical foundation for microplastic control strategies based on pigment photosensitivity.