We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Increased adsorption of diflubenzuron onto polylactic acid microplastics after ultraviolet weathering can increase acute toxicity in the water flea (Daphnia magna)
Summary
Researchers found that UV-weathered biodegradable polylactic acid microplastics absorbed significantly more of the pesticide diflubenzuron than conventional PET microplastics, leading to greater toxicity in water fleas. The weathering process created more surface cracks and functional groups on the biodegradable plastic, increasing its ability to carry harmful chemicals. The study challenges the perception that biodegradable plastics are inherently safer, showing they may actually enhance pesticide toxicity in aquatic environments after environmental aging.
The ultraviolet (UV) weathering of microplastics (MPs) can lead to higher adsorption of harmful contaminants, thus increasing the potential risks of their combined effects. Because biodegradable MPs are more susceptible to UV weathering than conventional MPs, concerns have arisen about their ecological toxicity and environmental impact. Therefore, this study investigated the mechanisms associated with the adsorption of the pesticide diflubenzuron (DFB) onto polylactic acid (PLA) MP particles after UV weathering and the acute effects (48 h) of their combination on the water flea Daphnia magna. These effects were also compared with those of the conventional MP polyethylene terephthalate (PET). UV weathering led to a greater number of cracks and pores in the PLA particles compared to PET, as well as a higher number of oxygen-based functional groups and a larger surface area. These surface changes in UV-weathered PLA particles promoted higher DFB adsorption, which in turn led to stronger acute toxicity for D. magna compared to UV-weathered PET particles. Combined exposure to 25 ng L DFB and both UV-weathered and non-UV-weathered MPs significantly reduced the chitin content in D. magna, while combined exposure to 12.5 ng L DFB and the MPs increased the chitin content. This effect was more pronounced for UV-weathered PLA exposure than UV-weathered PET exposure. The expression of the genes for chitinase and endocrine glycoprotein, both of which are closely associated with the toxic mechanisms of DFB, showed no significant changes with the combination of 25 ng L DFB and non-UV-weathered MPs but were significantly downregulated after UV weathering. Overall, the UV weathering of PLA promoted the adsorption of DFB, thus increasing its toxic effects. Our findings demonstrate the importance of considering the effects of UV weathering and interactions with environmental pollutants when assessing the ecological risks associated with biodegradable MPs.
Sign in to start a discussion.
More Papers Like This
Ecotoxicity of polylactic acid microplastic fragments to Daphnia magna and the effect of ultraviolet weathering
Scientists compared the toxicity of biodegradable PLA (polylactic acid) microplastics with conventional polyethylene microplastics on water fleas, a key species in aquatic food chains. The biodegradable PLA microplastics were actually more acutely toxic than conventional ones, partly because their higher density led to greater accumulation in the organisms. UV weathering further increased the toxicity of PLA microplastics, challenging the assumption that biodegradable plastics are automatically safer for the environment.
Adsorption/desorption behavior of degradable polylactic acid microplastics on bisphenol A under different aging conditions
Researchers studied how different types of UV-simulated aging affect the ability of polylactic acid microplastics to adsorb and release bisphenol A. The study found that aging conditions changed the surface properties of the biodegradable plastic, altering its interaction with this common environmental contaminant. The findings suggest that even biodegradable microplastics can act as carriers of harmful chemicals depending on their degradation state.
Adsorption behaviors of chlorpyrifos on UV aged microplastics
Researchers investigated how UV aging affects the adsorption of the pesticide chlorpyrifos on biodegradable and non-degradable microplastics, finding that UV irradiation significantly modified plastic surfaces and enhanced their capacity to carry organic pollutants.
Toxicity comparison of polylactic acid and polyethylene microplastics co-exposed with methylmercury on Daphnia magna
Researchers compared the toxicity of biodegradable polylactic acid microplastics with conventional polyethylene microplastics, both alone and in combination with methylmercury, on water fleas. The biodegradable microplastics caused greater harm, significantly reducing survival and reproduction while also increasing mercury accumulation in the organisms. The findings challenge the assumption that biodegradable plastics are always safer for the environment, suggesting they may actually enhance the toxicity of co-occurring pollutants.
The effect of UV exposure on conventional and degradable microplastics adsorption for Pb (II) in sediment
Researchers studied how UV aging affects the ability of conventional polyethylene and degradable polylactic acid microplastics to adsorb lead ions from aquatic sediment. They found that UV aging increased the surface area and oxygen content of both plastic types, enhancing their capacity to adsorb heavy metals. The study suggests that weathered microplastics in the environment may be more effective carriers of heavy metal contamination than pristine particles.