Hormetic dose-response relationships between polystyrene microplastics and nitrogen elimination decoded by biofilm dynamics in electro-assisted constructed wetlands

Microplastics can Alter the Nitrogen Cycle in Surface Flow Constructed Wetlands

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Both conventional PVC and biodegradable PLA microplastics disrupted nitrogen cycling in constructed wetlands, with PVC causing ammonium accumulation and PLA acting as a carbon source, while both enhanced biofilm formation and enzyme activities at higher concentrations. These polymer-specific effects on nitrogen dynamics reveal that microplastic contamination poses distinct and complex threats to the water treatment functions of natural and engineered wetlands.

Impact of microplastics on the treatment performance of constructed wetlands: Based on substrate characteristics and microbial activities

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Researchers found that polystyrene microplastic accumulation in constructed wetlands initially improved nitrogen removal efficiency but ultimately impaired treatment performance over a 370-day experiment, altering substrate characteristics and microbial community activities.

Effects of microplastics on carbon and nitrogen cycling in coastal wetlands: A critical meta-analysis

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This meta-analysis of over 1,000 data points from 34 studies found that microplastics significantly altered certain carbon and nitrogen cycling indicators in coastal wetlands under laboratory conditions, but tidal simulation experiments more representative of real environments showed no significant effects. The findings caution against over-interpreting lab results and highlight that tidal dynamics and vegetation factors are often missing from experimental designs.

Temporal dynamics of bacterial biofilms and their relationship with heavy metals on expanded polystyrene microplastics

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A year-long field exposure study on expanded polystyrene microplastics at an aquaculture farm in the South China Sea found significant seasonal variation in attached bacterial communities dominated by Pseudomonas and Exiguobacterium, with high correlations between bacterial composition and co-occurring heavy metals. The findings demonstrate that EPS microplastics in aquaculture environments serve as dynamic carriers of both pathogenic bacteria and heavy metals, posing compounding contamination risks to farmed seafood and the humans who consume it.

Temporal dynamics of bacterial and fungal colonization on polystyrene microplastics in floodplain soils