Monitoring of microplastic pollution in the Arctic: recent developments in polymer identification, quality assurance and control, and data reporting

Abstract

The pollution of the environment with plastics is of growing concern worldwide, including the Arctic region. While larger plastic pieces are a visible pollution issue, smaller microplastics are not visible with the naked eye. These particles are available for interaction by Arctic biota and have become a concern for animal and human health. The determination of microplastic properties includes several methodological steps, i.e. sampling, extraction, quantification and chemical identification. This review discusses suitable analytical tools for the identification, quantification and characterization of microplastics in the context of monitoring in the Arctic. It further addresses quality assurance and quality control (QA/QC) which is particularly important for the determination of microplastic in the Arctic, as both contamination and analyte losses can occur. It presents specific QA/QC measures for sampling procedures and for the handling of samples in the laboratory, either on land or on ship, and considering the small size of microplastics as well as the high risk of contamination. The review depicts which data should be mandatory to report, thereby supporting a framework for harmonized data reporting.

Finding the Balance between Research and Monitoring: When Are Methods Good Enough to Understand Plastic Pollution?

“…Similar methods for large plastics and marine litter are already being implemented, reflecting their early inclusion in monitoring recommendations (e.g., refs , ). Methods for microplastic analysis reached a certain baseline level of suitable sampling, extraction, and identification tools in recent years (e.g., refs , − ). Still, many techniques are targeted by method optimization approaches and improvement in the speed of analysis.…”

“…This has led to diverse approaches being adopted around the world. Of those instruments in place to begin monitoring (i.e., Descriptor 10 - EU MSFD), methods used to analyze plastics (especially microplastics) tend to vary in terms of sampling, sample extraction, identification, and data reporting. − Challenges posed by choice of methodological approach, as well as access to infrastructure to perform analysis, further complicate the matter. Subsequently, data on plastic presence in the environment vary in quality, resolution, and focus .…”

Abundance and distribution of microplastics in surface waters of the Kattegat/ Skagerrak (Denmark)

“…Thereby, a proper analysis of these MPs requires laborious sample preparation with several steps of chemical and enzymatic treatments (Löder et al, 2017) and μFTIR techniques. Furthermore, prevention of contamination and strict quality control to estimate contamination during sampling and analyses of samples is particularly relevant for precisely determining the small-size MPs fractions (Wesch et al, 2017;Hermsen et al, 2018;Koelmans et al, 2019;Brander et al, 2020;Primpke et al, 2022).…”

Efficient extraction of small microplastic particles from rat feed and feces for quantification

“…However, to assess the risk, exposure studies need to be evaluated in context with environmental contamination in the same size class and chemical identity. Current detection methods are insufficient to quantify MP in the small micrometre range, if not marked by rare metals, isotopes or fluorescence before exposure, and need considerable method development [ 30 ]. Recently several interesting approaches aiming at small MP quantification have been published [ 31 , 32 ], but recovery and proficiency tests still need to be improved and developed, respectively.…”

“…These range from visual identification preceded by a simple density separation step [ 39 , 50 ] or digestion protocol [ 36 ] to identification of plastic polymers by FTIR (Fourier-Transform InfraRed) spectroscopy preceded by more complex extraction protocols [ 40 , 51 ]. While microscopic individual identification of MP by identification methods such as FTIR, LDIR (Laser Direct Infrared) or Raman is meaningful for characterization of the contamination including the size distribution, it is also a time-consuming endpoint analysis [ 30 ]. For exposure control in laboratory studies or surveillance tasks requiring true quantification with a higher sample throughput, pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) methods may be the better choice due to a faster analysis time of larger numbers of small particles.…”