Submicron Plastic Adsorption by Peat, Accumulation in Sphagnum Mosses and Influence on Bacterial Communities in Peatland Ecosystems

Analytical methods for quantifying PS and PVC Nanoplastic attachment to activated sludge Bacteria and their impact on community structure

Nanoplastics are anticipated to be ubiquitous in various environmental compartments. However, challenges in analytical methods hinder our understanding of risks related to specific nanplastics characteristics such as size and chemical compositions, and interactions between nanoplastics and microorganisms. In this study, we applied fit-for-purpose analytical methods and techniques to understand how nanoplastic chemical composition influences their interaction with bacteria collected from activated sludge. When exposed to polystyrene (PS) and polyvinyl chloride (PVC) nanoplastics for 5 days, the nanoplastics attached to the bacteria. Specifically, on day 1, there was a significant predominance of PS nanoplastics over PVC ones of similar size and shape, possibly due to differences in their chemical composition. After 5 days, there is a substantial decrease in nanoplastics attached to bacteria, suggesting bacterial defence mechanisms may reduce particles attachment over time. The overall bacterial community structure demonstrated a high degree of resilience. This resilience highlights the ability of microbial communities to maintain their structure despite nanoplastic stressors, as evidenced by consistent alpha diversity, PCoA, and PERMANOVA results. Understanding these mechanisms is crucial for assessing nanoplastic fate and thus environmental impacts.

Analysis of environmental biological effects and OBT accumulation potential of microalgae in freshwater systems exposed to tritium pollution

The ecological risk of tritiated wastewater into the environment has attracted much attention. Assessing the ecological risk of tritium-containing pollution is crucial by studying low-activity tritium exposure's environmental and biological effects on freshwater micro-environment and the enrichment potential of organically bound tritium (OBT) in microalgae and aquatic plants. The impact of tritium-contaminated wastewater on the microenvironment of freshwater systems was analyzed using microcosm experiments to simulate tritium pollution in freshwater systems. Low activity tritium pollution (105 Bq/L) induced differences in microbial abundance, with Proteobacteria, Bacteroidota, and Desulfobacterota occupying important ecological niches in the water system. Low activity tritium (105-107 Bq/L) did not affect the growth of microalgae and aquatic plants, but OBT was significantly enriched in microalgae and two aquatic plants (Pistia stratiotes, Spirodela polyrrhiza), with the enrichment coefficients of 2.08-3.39 and 1.71-2.13, respectively. At the transcriptional level, low-activity tritium (105 Bq/L) has the risk of interfering with gene expression in aquatic plants. Four dominant cyanobacterial strains (Leptolyngbya sp., Synechococcus elongatus, Nostoc sp., and Anabaena sp.) were isolated and demonstrated good environmental adaptability to tritium pollution. Environmental factors can modify the tritium accumulation potential in cyanobacteria and microalgae, theoretically enhancing food chain transfer.