Identification and quantification of microplastics in wastewater using focal plane array-based reflectance micro-FT-IR imaging

Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.This work is funded by a NERC (Natural Environment Research Council) CASE studentship (NE/K007521/1) with contribution from industrial partner Fera Science Ltd., United Kingdom. The authors would like to thank Peter Vale, from Severn Trent Water Ltd, for providing access to and additionally Ashley Howkins (Brunel University London) for providing travel and assistance with the sampling of the Severn Trent wastewater treatment plant in Derbyshire, UK. We are grateful to Emma Bradley and Chris Sinclair for providing helpful suggestions for our research

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

Marine Litter: Are There Solutions to This Environmental Challenge?

Between 1950 and 2015, it is estimated that 6300 Mt of plastic waste have been produced. Of this,around the 80% ended up in landfills or in the natural environment [1]. The combination of this typeof waste disposal and of the durability and resistance to degradation of plastics, has led to the currentubiquitous and abundant presence of plastic debris in the environment. The greatest warning signalof this plastic pollution problems has come from marine environment, where it is estimated that 75%of all marine litter is plastic and this debris has been reported to be accumulating at the sea surface[2], on shorelines of the most remote islands [3], in the deep sea [4] and in arctic sea ice [5]. Despitefirst reports on marine plastic litter dates back to the 1960s (Kenyon & Kridler, 1969) only recentlyit has been recognized as a pervasive global issue [1].There is a range of evidence on the harm caused by marine litter; with negative impacts oncommercial fisheries, maritime industries and infrastructures, as well as on a wide range of marineorganisms as a consequence of entanglement and ingestion [6].Plastic debris can be defined and described according to different characteristics including origin,polymer type, shape, size, colour or original use. However, the main classification used is about thesize: macroplastic (\u3e20 mm diameter), mesoplastic (5–20 mm) and microplastic (\u3c5 mm) [7]. Sincemacroplastics are more visible, they have been for long time considered as one of the most concerningforms of plastic pollution. In fact, these items can be more easily recognized and categorisedaccording to their original usage (i.e. fishing, packaging, or sewage related debris). More subtle andcomplicate is instead the pollution related to the presence of microplastics that, with accumulatingdata on the impact and consequences of such debris, has received increasing research interest andcurrently represents one of the greatest challenges in the fight against plastic pollutio

Freshwater Sponges Have Functional, Sealing Epithelia with High Transepithelial Resistance and Negative Transepithelial Potential

Epithelial tissue — the sealed and polarized layer of cells that regulates transport of ions and solutes between the environment and the internal milieu — is a defining characteristic of the Eumetazoa. Sponges, the most ancient metazoan phylum [1], [2], are generally believed to lack true epithelia [3], [4], [5], but their ability to occlude passage of ions has never been tested. Here we show that freshwater sponges (Demospongiae, Haplosclerida) have functional epithelia with high transepithelial electrical resistance (TER), a transepithelial potential (TEP), and low permeability to small-molecule diffusion. Curiously, the Amphimedon queenslandica sponge genome lacks the classical occluding genes [5] considered necessary to regulate sealing and control of ion transport. The fact that freshwater sponge epithelia can seal suggests that either occluding molecules have been lost in some sponge lineages, or demosponges use novel molecular complexes for epithelial occlusion; if the latter, it raises the possibility that mechanisms for occlusion used by sponges may exist in other metazoa. Importantly, our results imply that functional epithelia evolved either several times, or once, in the ancestor of the Metazoa

Sources, Distribution, and Fate of Microscopic Plastics in Marine Environments

Microplastics are pieces of plastic debris <5 mm in diameter. They enter the environment from a variety of sources including the direct input of small pieces such as exfoliating beads used in cosmetics and as a consequence of the fragmentation of larger items of debris. A range of common polymers, including polyethylene, polypropylene, polystyrene, and polyvinyl chloride, are present in the environment as microplastic particles. Microplastics are widely distributed in marine and freshwater habitats. They have been reported on shorelines from the poles to the equator; they are present at the sea surface and have accumulated in ocean systems far from land. Microplastics are also present in substantial quantities on the seabed. A wide range of organisms including birds, fish, and invertebrates are known to ingest microplastics and for some species it is clear that a substantial proportion of the population have microplastic in their digestive tract. The extent to which this might have harmful effects is not clear; however, the widespread encounter rate indicates that substantial quantities of microplastic may be distributed within living organisms themselves as well as in the habitats in which they live. Our understanding about the long-term fate of microplastics is relatively limited. Some habitats such as the deep sea may be an ultimate sink for the accumulation of plastic debris at sea; indeed, some recent evidence indicates quantities in the deep sea can be greater than at the sea surface. It has also been suggested that microplastics might be susceptible to biodegradation by microorganisms; however, this is yet to be established and the prevailing view is that even if emissions of debris to the environment are substantially reduced, the abundance of microplastics will increase over the next few decades. However, it is also clear that the benefits which plastics bring to society can be realized without the need for emissions of end-of-life plastics to the ocean. To some extent the accumulation of microplastic debris in the environment is a symptom of an outdated business model. There are solutions at hand and many synergistic benefits can be achieved in terms of both waste reduction and sustainable use of resources by moving toward a circular economy

Data associated with Matveev et al: Sense Induced Flow - Active use of ambient flow by a deep-sea glass sponge

How flow moves through porous structures like sponges is a fluid dynamic problem that has challenged physical and biological scientists. Sponges possess biological pump cells that are known to drive water flow, and yet their porous bodies have often been proposed to take advantage of ambient currents passively. Here we focus on the ‘induced-flow’ theory which proposes that pipe-shaped structures can allow flow external to the tube to drive flow through the tube. This concept has been widely applied to both living systems and biogenic structures and particularly resonates with paleontologists who often give a poriferan-affinity to fossils with holes, assuming that the canals of sponges are inert. A modern understanding of sponge morphology and physiology however, shows sponges possess a sophisticated sensory system, even in the canals. Glass sponges (Hexactinellida) are an ideal group with which to re-examine the hypothesis because individuals have large oscula and have a well-studied sensory system that can cause feeding current arrests. Here we studied filtration and metabolism from glass sponges in their natural habitat on a glass sponge reef at 190m depth. We used custom oxygen and flow sensors to record oxygen removed per liter pumped over several tidal cycles, to test the hypothesis that the glass sponge Aphrocallistes vastus expends less energy to filter more water during higher ambient flow. We found that more water was filtered during periods of higher ambient current in only one of six individuals. However, all sponges arrested pumping independently of ambient currents, indicating they have control over pumping. We compared oxygen removal between low and high ambient flow during periods when sponges were pumping (high excurrent). Surprisingly, four of six sponges removed on average 30% less oxygen when the ambient current was high. This suggests a mechanism by which the sponge senses the increase in ambient flow rates and reduces the cost of filtration. The underlying mechanism by which the sponges sense the change in ambient current and control the flow through its body remains unknown, but may involve feedback from primary cilia at the osculum that are involved in flow sensing and dilation of canals in other sponges. Our experiments show that while sponges can take advantage of current-induced flow, the flow through these animals is controlled by their complex physiology. Overall these results imply that the feedback system in nerveless sponges functions in a manner similar to other animals formed by tubes