Microplastic-Associated Biofilms: A Comparison of Freshwater and Marine Environments

Microplastics (<5 mm particles) occur within both engineered and natural freshwater ecosystems, including wastewater treatment plants, lakes, rivers, and estuaries. While a significant proportion of microplastic pollution is likely sequestered within freshwater environments, these habitats also constitute an important conduit of microscopic polymer particles to oceans worldwide. The quantity of aquatic microplastic waste is predicted to dramatically increase over the next decade, but the fate and biological implications of this pollution are still poorly understood. A growing body of research has aimed to characterize the formation, composition, and spatiotemporal distribution of microplastic-associated (“plastisphere”) microbial biofilms. Plastisphere microorganisms have been suggested to play significant roles in pathogen transfer, modulation of particle buoyancy, and biodegradation of plastic polymers and co-contaminants, yet investigation of these topics within freshwater environments is at a very early stage. Here, what is known about marine plastisphere assemblages is systematically compared with up-to-date findings from freshwater habitats. Through analysis of key differences and likely commonalities between environments, we discuss how an integrated view of these fields of research will enhance our knowledge of the complex behavior and ecological impacts of microplastic pollutants

Understanding How Microplastics Affect Marine Biota on the Cellular Level Is Important for Assessing Ecosystem Function: A Review

Plastic has become indispensable for human life. When plastic debris is discarded into waterways, these items can interact with organisms. Of particular concern are microscopic plastic particles (microplastics) which are subject to ingestion by several taxa. This review summarizes the results of cutting-edge research about the interactions between a range of aquatic species and microplastics, including effects on biota physiology and secondary ingestion. Uptake pathways via digestive or ventilatory systems are discussed, including (1) the physical penetration of microplastic particles into cellular structures, (2) leaching of chemical additives or adsorbed persistent organic pollutants (POPs), and (3) consequences of bacterial or viral microbiota contamination associated with microplastic ingestion. Following uptake, a number of individual-level effects have been observed, including reduction of feeding activities, reduced growth and reproduction through cellular modifications, and oxidative stress. Microplastic-associated effects on marine biota have become increasingly investigated with growing concerns regarding human health through trophic transfer. We argue that research on the cellular interactions with microplastics provide an understanding of their impact to the organisms’ fitness and, therefore, its ability to sustain their functional role in the ecosystem. The review summarizes information from 236 scientific publications. Of those, only 4.6% extrapolate their research of microplastic intake on individual species to the impact on ecosystem functioning. We emphasize the need for risk evaluation from organismal effects to an ecosystem level to effectively evaluate the effect of microplastic pollution on marine environments. Further studies are encouraged to investigate sublethal effects in the context of environmentally relevant microplastic pollution conditions

Microplastics in Soil Ecosystem : Insight on Its Fate and Impacts on Soil Quality

Plastic film has been intensively used in (semi-)arid agricultural regions, attributing to its great benefits of improving soil productivity and crop yield in China. However, plastic debris, as a consequence of film mulching, remains and accumulates in soil leading to severe soil quality problems, as well as environmental concerns especially the small fragmented particles referred to as microplastics (MPs). Though increasing attention has been aroused for MPs in the aquatic environment, the knowledge of MPs’ behavior and its effects on soil quality is extremely insufficient and urgently needed. In this study, we oriented the benefits of plastic film use, its contribution to agriculture productivity, and the effects of MPs on soil properties and its related soil quality indicators. Admittedly, the increasing trend of using plastic film made by light density of polyethylene would be continued in China, and the pieces of plastic particles would either be persistent and accumulated in soil layers or be slowly aging and degraded. The impacts of MPs on soil quality need more attention due to the limited studies available focusing on its fate and interactions associated with soil ecosystem services and environmental resilience. Although policies and agricultural extending services on plastic film application have been laughed for a few years, alternative materials used for producing environment-friendly film, plastic debris recycling, and solutions on pieced particle removal are the great challenges for sustainable farming. Thus, it is urgent to understand MPs’ effects on soil quality which is crucial for soil-plant system and soil pollution monitoring and prevention.</p