Development and Validation of an Efficient Method for Processing Microplastics in Biota Samples

Abstract

The impacts of microplastics on aquatic ecosystems and biota are gaining attention globally. Although microplastics have been widely detected in biota, there currently are few standardized detection and identification methods. The present study developed a novel one‐step digestion method which was evaluated with mussel and fish samples. This method employed nitric acid and hydrogen peroxide (HNO3:H2O2 = 4:1 by volume) as digestion reagents, which completely digested biota samples <5 g weight within 30 min at 50 °C. A density separation step was subsequently used to remove organic residues as necessary. The efficiency and suitability of this method were tested by spiking microplastics of 7 different types and of various sizes (1000, 900, 675, 300, 250, and 150 μm) into mussel and gastrointestinal tracts of fish. The recoveries of microplastics ranged from 90 to 100%. No significant changes in weight, surface area, and particle size (t test, p > 0.05) were observed for all tested polymers. Fourier transform infrared spectral analyses demonstrated that the method did not degrade any of the polymers except for polyethylene terephthalate. The method was demonstrated with mussel and fish samples collected from the Pearl River delta, south China, and was able to recover microplastics effectively. Overall, the present method is time‐saving and easy to operate, with low procedural cross‐contamination. The properties of microplastics recovered by the present method remained largely intact, greatly benefiting subsequent qualitative and quantitative analyses. Environ Toxicol Chem 2019;38:1400–1408. © 2019 SETAC

Overview of global status of plastic presence in marine vertebrates

“…This is largely because the methodology used is still under discussion and several different techniques are currently used depending on species and locations (Provencher et al., 2019). Many studies (Hermsen et al., 2018; Rocha‐Santos & Duarte, 2015; Wesch et al., 2016; Yu et al., 2019; Zhang et al., 2019) have claimed that a comprehensive assessment of macro‐ and microplastic ingestion is needed to establish standardized techniques and identify reliable observation methods, which would allow for comparison of results between species and geographical areas. Additionally, the identification of potential gaps will allow for a better understanding of the impact that plastics have at the individual, population, species and ecosystem levels.…”

A rapid method for extracting microplastics from oily food samples

“…Biota samples (mussel and sh) can be digested in a HNO 3 -: H 2 O 2 mixture solution (v/v ¼ 4 : 1) at 50 C for 30 min. 27 In addition, canola oil was used to separate MPs from sediments and the oil was removed with ethanol. 31 We adopted a HNO 27,32,33 the MPs in aquatic organisms can be extracted using a digestion reagent alone and without the residual oil on the surface of MPs.…”

“…Common chemical reagents including acids, alkalies, oxidants and enzymes were used as digestion solutions. [24][25][26][27] Aer otation using reagents such as sodium chloride or sodium iodide, MPs were ltered using membranes. 28,29 However, the oil in food cannot be digested effectively in a short time and MPs are usually oleophilic, which affects the identication of polymers later, and Crichton et al (2017) also demonstrated that oils interfered with the spectrum of MPs.…”

Isolation and Extraction of Microplastics from Environmental Samples: An Evaluation of Practical Approaches and Recommendations for Further Harmonization

“…Digestion methods may involve some form of pre-treatment to increase efficiency of digestion. For example, mussel soft tissue is often extracted from the shell, [80][81][82] thereby reducing the complexity of the matrix for digestion. Once removed from the shells, mussels can be treated similarly to other soft tissue biota (e.g., fish fillet).…”