We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Enhanced aging of polystyrene microplastics in sediments under alternating anoxic-oxic conditions
Summary
Researchers discovered that alternating anoxic-oxic conditions in sediments significantly enhanced the aging and degradation of polystyrene microplastics, challenging the assumption that microplastic aging is limited to sunlit areas.
Aging of microplastics (MPs) (i.e., degradation and weathering) is ubiquitous in the environment. The MP aging process is thought to be limited to light and static areas, while aging in dark and fluctuating anoxic-oxic areas is poorly understood. Here, we provide initial evidence for aging of polystyrene microplastics (PS-MPs) under different anoxic/oxic conditions in sediments, and we further explored these mechanisms using sediment column experiments and pure-culture experiments. The results showed that PS-MPs in alternating anoxic-oxic sediments displayed the highest degree of aging. In the in-situ experiment, both the weight losses and O/C ratios of PS-MPs aged under alternating anoxic-oxic conditions were ∼2 times higher than those aged under static oxic and static anoxic conditions during 2-month experiments. In a 2-month column experiment, the PS-MPs in the alternating anoxic-oxic group showed weight losses and O/C ratios that were, respectively, triple and double the corresponding values for the static oxic and static anoxic groups. Column and pure-culture experiments demonstrated that dark production of ·OH which showed a positive correlation with a Fe redox process could explain enhanced MP aging under the alternating anoxic-oxic conditions. These findings provide a basis for risk assessment and management of MPs in the natural environment, such as in intertidal zones and paddy fields, and also have implications for engineering of optimized MP degradation processes.
Sign in to start a discussion.
More Papers Like This
Dissolved Organic Matter Promotes the Aging Process of Polystyrene Microplastics under Dark and Ultraviolet Light Conditions: The Crucial Role of Reactive Oxygen Species
Researchers found that dissolved organic matter commonly present in natural water environments accelerates the aging and degradation of polystyrene microplastics under both dark and ultraviolet light conditions. The study identified reactive oxygen species as the crucial driver of this aging process, with fulvic acid showing a stronger effect than humic acid due to its greater ability to generate semiquinone radicals.
Probing the aging process and mechanism of microplastics under reduction conditions
Researchers investigated how microplastics age under oxygen-depleted reduction conditions rather than the more commonly studied oxidative environments, finding that reduction conditions still alter microplastic surface properties and may affect their environmental behavior in anaerobic sediments and deep waters.
Photoaging of Polyvinyl Chloride and Polystyrene Under UVA Radiation in Diverse Environmental Conditions
Researchers exposed polyvinyl chloride and polystyrene plastics to UVA radiation under diverse environmental conditions and tracked their photoaging and fragmentation, finding that UVA exposure accelerates microplastic generation in ways that vary with environmental context.
Understanding microplastic aging driven by photosensitization of algal extracellular polymeric substances
Researchers found that substances released by algae significantly speed up the breakdown of polystyrene microplastics under sunlight. The algal compounds generate reactive molecules that attack the plastic surface, creating smaller fragments and releasing dissolved organic matter. The findings are particularly relevant for understanding how microplastics degrade in waterways affected by algal blooms.
Effects and mechanisms of aged polystyrene microplastics on the photodegradation of sulfamethoxazole in water under simulated sunlight
Researchers found that aged polystyrene microplastics inhibited the photodegradation of the antibiotic sulfamethoxazole in water, with inhibition increasing proportionally to the aging degree due to light-scattering effects and reactive oxygen species quenching.