Quantitative assessment of visual microscopy as a tool for microplastic research: Recommendations for improving methods and reporting

Kotar, Syd; McNeish, Rae; Murphy-Hagan, Clare; Renick, Violet Compton; Lee, Chih-Fen T.; Steele, Clare; Lusher, Amy; Moore, Charles J.; Minor, Elizabeth C.; Schroeder, Joseph H.; Helm, Paul A.; Rickabaugh, Keith; Frond, Hannah De; Gesulga, Kristine; Lao, Wenjian; Munno, Keenan; Hampton, Leah M. Thornton; Weisberg, Stephen B.; Wong, Charles S.; Amarpuri, Gaurav; Barnett, Steven M.; Christiansen, Silke; Cowger, Win; Crampond, Kévin; Du, Fangni; Gray, Andrew B.; Hankett, Jeanne M.; Ho, Kay T.; Jaeger, Jost; Lilley, Claire; Mai, Lei; Mina, Odette; Lee, Eunah; Primpke, Sebastian; Singh, Samiksha; Skovly, Joakim; Slifko, Theresa R.; Sukumaran, Suja; Bavel, Bert van; Brocklin, Jennifer Van; Vollnhals, Florian; Wu, Chenxi; Rochman, Chelsea M.

doi:10.1016/j.chemosphere.2022.136449

Cited by 45 publications

(14 citation statements)

References 20 publications

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“…However, it is important to note that limitations still exist in the field with respect to quantifying microplastics in environmental samples. For example, fiber loss in field sampling and the detection of smaller microplastics remain challenges (Barrows et al, 2017; Kotar et al, 2022). In addition, microplastic concentration is known to be spatially and temporally heterogeneous (Tamminga & Fischer, 2020), so the use of “environmentally relevant concentrations” as in the present study may not represent all scenarios in nature.…”

Section: Discussionmentioning

confidence: 99%

No Effect of Realistic Concentrations of Polyester Microplastic Fibers on Freshwater Zooplankton Communities

Klasios,

Kim,

Tseng

2024

Enviro Toxic and Chemistry

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Zooplankton are a conduit of energy from autotrophic phytoplankton to higher trophic levels, and they can be a primary point of entry of microplastics into the aquatic food chain. Investigating how zooplankton communities are affected by microplastic pollution is thus a key step towards understanding ecosystem‐level effects of these global and ubiquitous contaminants. Although the number of studies investigating the biological effects of microplastics has grown exponentially in the last decade, the majority have used controlled laboratory experiments to quantify the impacts of microplastics on individual species. Given that all organisms live in multi‐species communities in nature, here we use an outdoor 1130L mesocosm experiment to investigate the effects of microplastic exposure on natural assemblages of zooplankton. We endeavored to simulate an environmentally relevant exposure scenario by manually creating ~270,000 0.015mm x 1‐1.5mm polyester fibers and inoculating mesocosms with zero, low (10 particles/L) or high (50 particles/L) concentrations. We recorded zooplankton abundance and community composition three times throughout the 12‐week study. We found no effect of microplastics on zooplankton abundance, Shannon diversity, or Pielou's evenness. NMDS plots also revealed no effects of microplastics on zooplankton community composition. Our study provides a necessary and realistic baseline upon which future studies can build. Because numerous other stressors faced by zooplankton (e.g. food limitation, eutrophication, warming temperatures, pesticides) are likely to exacerbate the effects of microplastics, we caution against concluding that polyester microfibers will always have no effect on zooplankton communities. Instead, we encourage future studies to investigate the triple threats of habitat degradation, climate warming, and microplastic pollution on zooplankton community health.

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Section: Discussionmentioning

confidence: 99%

No Effect of Realistic Concentrations of Polyester Microplastic Fibers on Freshwater Zooplankton Communities

Klasios,

Kim,

Tseng

2024

Enviro Toxic and Chemistry

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“…The use of a standard colour reference has been suggested to overcome inter‐observer subjectivity and allow for the use of more categories (Martí et al., 2020; Provencher et al., 2017), but to date few have adopted this approach, likely because it is time consuming to do manually. As plastics become smaller it also becomes increasingly more difficult to visually assess colour and thus the use of a standard colour reference may be limited to larger plastic fragments (Kotar et al., 2022; Lusher et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

“…When these properties are reported, most are determined by hand: researchers manually counting pieces of plastic, measuring their size with callipers or by sieving, and categorising colour based on visual inspection (Lavers et al., 2021; Provencher et al., 2017). Even with training, such methods can be slow, laborious and prone to human error or unintended bias (Kotar et al., 2022). The assessment of colour is particularly subjective; the apparent colour of an object will vary significantly depending on lighting and context and may be categorised differently by different people, which necessitates a relatively small number of colour categories for reproducibility.…”

Section: Introductionmentioning

confidence: 99%

Quantitative photography for rapid, reliable measurement of marine macro‐plastic pollution

Razzell Hollis,

Henderson,

Lavers

et al. 2023

Methods Ecol Evol

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Plastics are now ubiquitous in the environment and have been studied in wildlife and in ecosystems for more than 50 years. Measurement of size, shape and colour data for individual fragments of plastic is labour‐intensive, unreliable and prone to observer bias, particularly when it comes to assessment of colour, which relies on arbitrary and inconsistently defined colour categorisations. There is a clear need for a standard method for data collection on plastic pollution, particularly one that can be readily automated given the number of samples involved. This study describes a new method for standardised photography of marine plastics in the 1–100 mm size range (meso‐ and macro‐plastics), including colour correction to account for any image‐to‐image variation in lighting that may impact colour reproduction or apparent brightness. Automated image analysis is then applied to detect individual fragments of plastic for quantitative measurement of size, shape, and colour. The method was tested on 3793 fragments of debris ingested by Flesh‐footed Shearwaters (Ardenna carneipes) on Lord Howe Island, Australia, and compare results from photos taken in two separate locations using different equipment. Photos were acquired of up to 250 fragments at a time with a spatial resolution of 70 μm/pixel and were colour‐corrected using a reference chart to ensure accurate reproduction of colour. The automated image analysis pipeline was found to have a 98% success rate at detecting fragments, and the different size and shape parameters that can be outputted by the pipeline were compared in terms of usefulness. The evidence shown in this study should strongly encourage the uptake of this method for cataloguing macro‐scale plastic pollution, as it provides substantially higher quality data with accurate, reliable measurements of size, shape and colour for individual plastics that can be readily compared between disparate datasets.

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“…For larger particles, environmental and/or organismal plastic detection is conducted visually ( Moser and Lee, 1992 ; Eriksen et al, 2014 ; Van Sebille et al, 2015 ; Forrest and Hindell, 2018 ; Kotar et al, 2022 ). Additional methods and plastic detection and quantification include: Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and Pyrolysis-gas chromatography coupled to mass spectrometry ( Bouwmeester et al, 2015 ; Renner et al, 2018 ; Primpke et al, 2020 ; Cowger et al, 2021 ).…”

Section: Detecting and Estimating Exposure To Nanoscale Plasticsmentioning

confidence: 99%

Critical gaps in nanoplastics research and their connection to risk assessment

et al. 2023

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Reports of plastics, at higher levels than previously thought, in the water that we drink and the air that we breathe, are generating considerable interest and concern. Plastics have been recorded in almost every environment in the world with estimates on the order of trillions of microplastic pieces. Yet, this may very well be an underestimate of plastic pollution as a whole. Once microplastics (<5 mm) break down in the environment, they nominally enter the nanoscale (<1,000 nm), where they cannot be seen by the naked eye or even with the use of a typical laboratory microscope. Thus far, research has focused on plastics in the macro- (>25 mm) and micro-size ranges, which are easier to detect and identify, leaving large knowledge gaps in our understanding of nanoplastic debris. Our ability to ask and answer questions relating to the transport, fate, and potential toxicity of these particles is disadvantaged by the detection and identification limits of current technology. Furthermore, laboratory exposures have been substantially constrained to the study of commercially available nanoplastics; i.e., polystyrene spheres, which do not adequately reflect the composition of environmental plastic debris. While a great deal of plastic-focused research has been published in recent years, the pattern of the work does not answer a number of key factors vital to calculating risk that takes into account the smallest plastic particles; namely, sources, fate and transport, exposure measures, toxicity and effects. These data are critical to inform regulatory decision making and to implement adaptive management strategies that mitigate risk to human health and the environment. This paper reviews the current state-of-the-science on nanoplastic research, highlighting areas where data are needed to establish robust risk assessments that take into account plastics pollution. Where nanoplastic-specific data are not available, suggested substitutions are indicated.

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Quantitative assessment of visual microscopy as a tool for microplastic research: Recommendations for improving methods and reporting

Cited by 45 publications

References 20 publications

No Effect of Realistic Concentrations of Polyester Microplastic Fibers on Freshwater Zooplankton Communities

No Effect of Realistic Concentrations of Polyester Microplastic Fibers on Freshwater Zooplankton Communities

Quantitative photography for rapid, reliable measurement of marine macro‐plastic pollution

Critical gaps in nanoplastics research and their connection to risk assessment

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