Microplastic in Surface Waters of Urban Rivers: Concentration, Sources, and Associated Bacterial Assemblages

By A. McCormick, T. Hoellein, Maxwell G. London, Joshua Hittie, John W. Scott, J. Kelly. 2016

484 citations recorded by the source corpus.

The ecological dynamics of microplastic (<5 mm) are well documented in marine ecosystems, but the sources, abundance, and ecological role of microplastic in rivers are unknown and likely to be substantial. Microplastic fibers (e.g., synthetic fabrics) and pellets (e.g., abrasives in personal care products) are abundant in wastewater treatment plant (WWTP) effluent, and can serve as a point source of microplastic in rivers. The buoyancy, hydrophobic surface, and long transport distance of microplastic make it a novel substrate for the selection and dispersal of unique microbial assemblages. We measured microplastic concentration and bacterial assemblage composition on microplastic and natural surfaces upstream and downstream of WWTP effluent sites at nine rivers in Illinois, United States. Microplastic concentration was higher downstream of WWTP effluent outfall sites in all but two rivers. Pellets, fibers, and fragments were the dominant microplastic types, and polymers were identified as polypropylene, polyethylene, and polystyrene. Mean microplastic flux was 1,338,757 pieces per day, although the flux was highly variable among nine sites (min = 15,520 per day, max = 4,721,709 per day). High-throughput sequencing of 16S rRNA genes showed bacterial assemblage composition was significantly different among microplastic, seston, and water column substrates. Microplastic bacterial assemblages had lower taxon richness, diversity, and evenness than those on other substrates, and microplastic selected for taxa that may degrade plastic polymers (e.g., Pseudomonas) and those representing common human intestinal pathogens (e.g., Arcobacter). Effluent from WWTPs in rivers is an important component of the global plastic “life cycle,” and microplastic serves as a novel substrate that selects and transports distinct bacterial assemblages in urban rivers. Rates of microplastic deposition, consumption by stream biota, and the metabolic capacity of microplastic biofilms in rivers are unknown and merit further research.

Subfields: Biomaterials, Industrial and Manufacturing Engineering, Pollution

View Paper: https://www.semanticscholar.org/paper/e008650192ecf08a2b8ef81058e26d1ff800897e

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Citations in the corpus

Microplastics in freshwaters and drinking water: Critical review and assessment of data quality (2019, background): “Some precautions are less reliable but still provide some useful information on the level of contamination, like the filtration of air, or the sole examination of petri dishes/soaked papers placed next to the samples (Cable et al., 2017; Dris et al. 2015, 2018b; Estahbanati and Fahrenfeld, 2016; Hen”
Direct and indirect effects of microplastics on bivalves, with a focus on edible species: A mini-review (2019, background): “In addition, microplastics have the potential to deliver hazardous microbes to humans; common human intestinal pathogens such as Arcobacter spp. associated with bacteremia, gastroenteritis and diarrhea have been found on microplastics (Figueras et al., 2014; McCormick et al., 2016).”
Microplastics as an emerging threat to terrestrial ecosystems (2018, background): “The three upper circular panels represent zoom on selected effects on soil chemistry (Fuller & Gautam, 2016), microbiome (Mccormick et al., 2016) and the biophysical environment (Huerta Lwanga et al., 2017; Liebezeit & Liebezeit, 2015; Maass et al., 2017; Rillig, Ziersch, et al., 2017; Zhu et al.,…”