A new small device made of glass for separating microplastics from marine and freshwater sediments

Nakajima, Reiko; Tsuchiya, Masashi; Lindsay, Dhugal J.; Kitahashi, Tomo; Fujikura, Katsunori; Fukushima, Tetsuya

doi:10.7717/peerj.7915

Cited by 62 publications

(34 citation statements)

References 36 publications

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“…In general, the process used to determine MP concentrations in sediment samples comprises extraction, separation, identification and quantification (Shim et al, 2017). Several methods have been developed for MP extraction from marine and beach sediment samples, including filtration, sieving, density separation, flotation, chemical decomposition, electrostatic separation, elutriation column optimisation and magnetic extraction using coated Fe nanoparticles to magnetise plastics (Felsing et al, 2018;Grbic et al, 2019;Hengstmann et al, 2018;Hidalgo-Ruz et al, 2012;Müller et al, 2020;Nakajima et al, 2019;Phuong et al, 2021). However, density separation is the most commonly applied method for isolating MPs from sediment and is based on the specific density difference between MPs and sediments to separate less dense plastic polymers from denser sediment particles (Coppock et al, 2017;Phuong et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Selection of a density separation solution to study microplastics in tropical riverine sediment

Duong

Nguyen

et al. 2022

Environ Monit Assess

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critical issue. It is necessary to identify the fate and sources of MPs in the environment, minimise their release and adverse effects. Compared to marine sediments, standardised methods for extracting and estimating the amount of MPs in freshwater sediments are relatively limited. The present study focuses on MP recovery efficiency of four commonly used salt solutions (NaCl, NaI, CaCl 2 and ZnCl 2 ) for isolating MPs during the density separation step from freshwater sediment.

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Section: Introductionmentioning

confidence: 99%

Selection of a density separation solution to study microplastics in tropical riverine sediment

Duong

Nguyen

et al. 2022

Environ Monit Assess

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“…Imhof et al (2012) sorted PP, PE, PS, PVC, and PET [40], and Coppock et al (2017) sorted PP and PVC by shutting off the liquid phase with a ball valve [43]. Nakajima et al (2019) sorted PP, PE, PS, PVC, and PET by shutting off the liquid phase with a partition plate [44]. In all cases, the density of the flotation medium ranged from 1.5 to 1.6 g/cm 3 , and the recovery rate was higher than 90%.…”

Section: Recovery Efficiency Of Each Sorting Methodsmentioning

confidence: 99%

“…On the other hand, Nakajima et al ( 2019) used a different method to prevent water leakage during partition plate insertion [44]. They made a container having a built-in partition plate instead of inserting it later, and moved the container instead of the partition plate (Figure 6b) [44]. After separation into floating matter and sinking matter, the floating matter can be collected by decantation.…”

Section: Bottle Methodsmentioning

confidence: 99%

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Plastic Bottles for Sorting Floating Microplastics in Sediment

Asakura

2022

JMSE

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Plastic waste’s near-permanent pollution of the natural environment is becoming an increasing concern. It is necessary to determine the amount of microplastics (MPs) present in the natural environment and reduce the amount of plastic waste. In this study, the author developed a simple sorting method for MPs in sediment, which can eliminate sediment and does not require filtration, using an apparatus available to the public. This sorting method, called the “bottle method”, can shut off floating matter from sediment and be used for sorting and washing at the same time. When the density of the solid sample is lower than the liquid density, the recovery rate is almost 100%, as theoretically predicted. The recovery rate of MPs by the bottle method is comparable to that by the other two methods, i.e., the spoon method and the overflow method, and the sorting time is reduced by approximately half. As for the dilution of the liquid by the bottle method, the ratio of actual concentration to theoretical concentration is in the range 0.86 to 1.36, and the dilution and washing of the liquid proceeds as theoretically predicted.

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“…Again, the presence of polymeric material in the construction of settling apparatuses could lead to possible sample contamination. Nakajima et al (2019b) engineered a simple all-glass separator, the JAMSTEC microplastic-sediment separator (JAMSS unit). It is comprised of two glass plates (Fig.…”

Section: Density and Other Physical Separationmentioning

confidence: 99%

Analytical Chemistry of Plastic Debris: Sampling, Methods, and Instrumentation

Hale

Seeley

King

et al. 2021

Environmental Contamination Remediation and Management

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Approaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include tire wear, paint chips, semisynthetics (e.g., rayon), and bioplastics. Plastics commonly contain chemical additives and fillers, which may alter their toxicological potency, behavior (e.g., buoyancy), or detector response (e.g., yield fluorescence) during analysis. Field sampling methods often focus on >20 μm and even >300 μm sized particles and will thus not capture smaller microplastics (which may be most abundant and bioavailable). Analysis of a limited subgroup (selected polymer types, particle sizes, or shapes) of microplastics, while often operationally necessary, can result in an underestimation of actual sample content. These shortcomings complicate calls for toxicological studies of microplastics to be based on “environmentally relevant concentrations.” Sample matrices of interest include water (including wastewater, ice, snow), sediment (soil, dust, wastewater sludge), air, and biota. Properties of the environment, and of the particles themselves, may concentrate plastic debris in select zones (e.g., gyres, shorelines, polar ice, wastewater sludge). Sampling designs should consider such patchy distributions. Episodic releases due to weather and anthropogenic discharges should also be considered. While water grab samples and sieving are commonplace, novel techniques for microplastic isolation, such as continuous flow centrifugation, show promise. The abundance of nonplastic particulates (e.g., clay, detritus, biological material) in samples interferes with microplastic detection and characterization. Their removal is typically accomplished using a combination of gravity separation and oxidative digestion (including strong bases, peroxide, enzymes); unfortunately, aggressive treatments may damage more labile plastics. Microscope-based infrared or Raman detection is often applied to provide polymer chemistry and morphological data for individual microplastic particles. However, the sheer number of particles in many samples presents logistical hurdles. In response, instruments have been developed that employ detector arrays and rapid scanning lasers. The addition of dyes to stain particulates may facilitate spectroscopic detection of some polymer types. Most researchers provide microplastic data in the form of the abundances of polymer types within particle size, polymer, and morphology classes. Polymer mass data in samples remain rare but are essential to elucidating fate. Rather than characterizing individual particles in samples, solvent extraction (following initial sample prep, such as sediment size class sorting), combined with techniques such as thermoanalysis (e.g., pyrolysis), has been used to generate microplastic mass data. However, this may obviate the acquisition of individual particle morphology and compositional information. Alternatively, some techniques (e.g., electron and atomic force microscopy and matrix-assisted laser desorption mass spectrometry) are adept at providing highly detailed data on the size, morphology, composition, and surface chemistry of select particles. Ultimately, the analyst must select the approach best suited for their study goals. Robust quality control elements are also critical to evaluate the accuracy and precision of the sampling and analysis techniques. Further, improved efforts are required to assess and control possible sample contamination due to the ubiquitous distribution of microplastics, especially in indoor environments where samples are processed.

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A new small device made of glass for separating microplastics from marine and freshwater sediments

Cited by 62 publications

References 36 publications

Selection of a density separation solution to study microplastics in tropical riverine sediment

Selection of a density separation solution to study microplastics in tropical riverine sediment

Plastic Bottles for Sorting Floating Microplastics in Sediment

Analytical Chemistry of Plastic Debris: Sampling, Methods, and Instrumentation

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