We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Effect of microplastics on sulfate reduction in landfill leachate-saturated zone
Summary
Researchers investigated how different types of microplastics affect sulfate reduction in landfill leachate-saturated zones at varying temperatures. They found that polylactic acid microplastics dramatically increased hydrogen sulfide release compared to polystyrene, polyethylene, and PVC, with cumulative release at 55 degrees Celsius being 33 times higher than at 25 degrees. The study suggests that biodegradable plastics in landfills may paradoxically worsen certain pollution processes by enriching sulfate-reducing microbial communities.
The sulfate reduction behavior in the leachate-saturated zone of landfills is significantly influenced by the type of microplastics (MPs) and temperature. This study established different temperature conditions based on the leachate-saturated zone of landfills to investigate the sulfate reduction behavior influenced by different types of MPs at different temperatures. The results showed that HS release was more intense under the influence of polylactic acid (PLA). Additionally, the cumulative HS release increased with rising temperature. In the PLA group, the cumulative HS release at 55 °C was 33.2, 2.3, and 1.4 times higher than at 25 °C, 35 °C, and 45 °C, respectively. The sulfate reduction behavior in the PS, PE, and PVC groups is relatively weak, with the cumulative HS release at 55 °C being only 0.004-0.01 times that of the PLA group. Compared to the influence of temperature, the type of MPs was the main factor contributing to significant differences in the dissimilatory sulfate reduction (DSR) process. The DSR functional genes were more easily enriched in PLA, leading to the release of large amounts of HS. However, for the assimilatory sulfate reduction (ASR) process, the overall consumption of SO for microbial synthesis of cell components was not significantly influenced by the type of MPs. Furthermore, temperature was the main factor contributing to significant differences in the ASR process, with the enrichment ability of MPs for ASR functional genes decreasing as the temperature increased. Additionally, compared to the PS, PE, and PVC, PLA was more conducive to the growth and enrichment of dissimilatory sulfate-reducing bacteria , but the dominant genus responsible for HS release was determined by temperature. The dominant genus changed from Desulfonatronum and Thermodesulfomicrobium at mid-to-low temperatures (25 °C and 35 °C) to Candidatus_Desulforudis at high temperatures (45 °C and 55 °C) in the PLA group. This study reveals the sulfate reduction behavior under the influence of MPs in the leachate-saturated zone of landfills, providing new insights for landfill management and pollution control, such as controlling the entry of microplastics at the source to reduce the risk of significant HS release.
Sign in to start a discussion.
More Papers Like This
Microplastic, a possible trigger of landfill sulfate reduction process
Researchers investigated microplastic occurrence in landfill environments through field sampling and found abundances reaching over 11,000 particles per gram in deeper soil layers. The study revealed a significant correlation between microplastic abundance and sulfate reduction metabolites, suggesting that microplastics may trigger the sulfate reduction process that contributes to landfill odor emissions.
Microplastic release and sulfate reduction response in the early stage of a simulated landfill
An experiment simulating a landfill found that microplastics rapidly leach into landfill liquid (leachate) during the early stages of waste decomposition, with circulating leachate carrying 1.45 times more microplastics than non-circulating systems. Larger plastic fragments broke down into smaller particles during the process, and a positive correlation was found between microplastic release and sulfate-reducing activity. Landfills represent an underappreciated but significant pathway for microplastics to enter groundwater and surrounding environments.
Differential effects of sulfide-induced transformation of biodegradable and conventional microplastics on sedimentary CO2 and CH4 emissions: Underlying microbiome-mediated mechanisms
Microplastics buried in sediments don't just sit inert — they interact with soil microbes in ways that affect how much methane and CO2 the sediment releases into the atmosphere. This incubation study found that fresh biodegradable plastic (PLA) dramatically increased greenhouse gas emissions, but once the plastic had aged through a chemical process called sulfidation, it actually suppressed them — while conventionally aged polyethylene had the opposite effect, boosting methane by stimulating methane-producing microbes. The findings complicate the assumption that biodegradable plastics are automatically better for the environment, and suggest that how plastics age underground matters as much as what they are made of.
Comparison of sulfide-induced transformation of biodegradable and conventional microplastics: Mechanism and environmental fate
Researchers compared how sulfide chemicals in oxygen-free environments (like deep sediments) transform biodegradable plastics versus conventional plastics. They found that biodegradable PBAT microplastics were more easily changed by sulfides than conventional polyethylene, releasing more dissolved organic carbon and potentially different environmental effects. This suggests that so-called biodegradable plastics may not behave as safely as expected when they break down in certain natural environments.
Investigating the impact of microplastics on sulfur mineralization in different soil types: A mechanism study
This study used soil microcosm experiments to investigate how polystyrene and polyphenylene sulfide microplastics affect sulfur mineralization in different soil types, revealing mechanisms by which MPs alter soil physicochemical properties and microbial activity.