We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Quantifying surface topography helps reveal the combined effects of microplastics UV-aging and organic matter on trace metal adsorption in seawater.
Summary
Sunlight exposure makes ocean microplastics rougher and more weathered, and this new study shows that "aged" plastic actually soaks up more toxic metals like copper and lead compared to fresh plastic. Since microplastics are found throughout seafood and drinking water, this matters because sun-damaged plastic particles could be carrying higher loads of harmful metals into the food chain than we previously realized.
This study explores the impact of UV-aging and organic matter (humic acid - HA) on adsorption of essential (Cu, Co, Ni) and nonessential (Cd, Pb) trace metals onto microplastics (MPs), polypropylene (PP) and polystyrene (PS), in seawater. Surface characterization using atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) revealed that UV aging significantly alters microplastic surface properties. AFM measurements show an increase in both surface roughness and surface area under UV radiation. This increase strongly correlated with enhanced metal adsorption, with uptake varying according to polymer type and aging state. Surface transformations upon prolonged MPs aging significantly altered the preferences of Cd, Co and Cu in adsorption dynamics. Cu and Pb showed the highest adsorbed amounts, especially on aged microplastics. The influence of HA was metal-specific and dependent on the aging state of the microplastics. HA had no significant effect on Cd, Co, Ni and Pb, but modulated Cu adsorption, enhancing it on unaged MPs and reducing it on aged MPs, which was consistent with the speciation modeling. This work is the first to assess the combined effects of organic matter and aged MPs on the adsorption of Cd, Co, and Ni in seawater, and to employ AFM for microplastic quantitative surface topography in such context.