Microbial ecology of microplastic biofilm in fresh- and wastewater

"Microplastics are emerging contaminants of concern in the freshwater environment due to their ecotoxicity to aquatic organisms. A secondary concern related to microplastic pollution is that these particles may serve as carriers of microbial communities from source waters into receiving waters. A limited number of field studies have raised alarm that the biofilm communities on microplastics in the fresh and marine water environment may possess pathogens, perhaps due to by-pass of disinfection processes for wastewater derived microplastics. Here, we were interested in understanding the role of source water quality, polymer type, and microplastic particle size on the resulting biofilm microbial communities. A controlled laboratory was performed to investigate the microbial communities observed in bulk water compared to those in the microplastic biofilm via high throughput sequencing. The biofilm community varied as a function of source water and polymer type, but not particle size. The biofilm microbial communities differed from the bulk water communities but using qPCR, they did not have a higher prevalence of indicator organisms based (BacHum gene copies / 16S rRNA gene copies). These data can help us better understand microprticle biofilms in different water environments."