Identification of microplastics using Raman spectroscopy: Latest developments and future prospects

Widespread microplastic pollution is raising growing concerns as to its detrimental effects upon living organisms. A realistic risk assessment must stand on representative data on the abundance, size distribution and chemical composition of microplastics. Raman microscopy is an indispensable tool for the analysis of very small microplastics (<20 μm). Still, its use is far from widespread, in part due to drawbacks such as long measurement time and proneness to spectral distortion induced by fluorescence. This review discusses each drawback followed by a showcase of interesting and easily available solutions that contribute to faster and better identification of microplastics using Raman spectroscopy. Among discussed topics are: enhanced signal quality with better detectors and spectrum processing; automated particle selection for faster Raman mapping; comprehensive reference libraries for successful spectral matching. A last section introduces non-conventional Raman techniques (non-linear Raman, hyperspectral imaging, standoff Raman) which permit more advanced applications such as real-time Raman detection and imaging of microplastics.

Catarina F. Araujo, Mariela M. Nolasco, Antonio M.P. Ribeiro, Paulo J.A. Ribeiro-Claro, Water Research, Volume 142, 1 October 2018, Pages 426-440

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Weathering impacts the uptake of polyethylene microparticles from toothpaste in Mediterranean mussels (M. galloprovincialis)

Mediterranean mussels (Mytilus galloprovincialis) were exposed over 21 days to polyethylene (PE) particles (0.01 mg ml−1; 50–570 μm) isolated from toothpaste. PE was deployed in the Outer Oslofjord (Norway) for 21 days, before exposing the mussels to both virgin (PE-V) and weathered PE (PE-W) particles. The mussels ingested both types of particles, but significantly more weathered particles were ingested than virgin (p = .0317), based on PE dosed by weight (mg ml−1) but not when considering particle number (PE-V: 1.18 ± 0.16 particles ml−1; PE-W 1.86 ± 0.66 particles ml-1;). PE particle ingestion resulted in structural changes to the gills and digestive gland, as well as necrosis in other tissues such as the mantle. No differences were found regarding the degree of tissue alteration between PE-virgin and PE-weathered exposures. This current study illustrates the importance of using weathered particles in microplastic exposure studies to reflect the behaviour of plastic particles after entering the marine environment. The observed tissue alterations demonstrate the potential adverse effects to mussels exposed to microplastic particles.

Inger Lise N. Brate, Mercedes Blazquez, Steven J. Brooks, Kevin V. Thomas, Science of The Total Environment, Volume 626, 1 June 2018, Pages 1310–1318

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Plastic microbeads ban enters force in UK

Manufacturing ban means the tiny beads which harm marine life can no longer be used in cosmetics and personal care product.

Plastic microbeads can no longer be used in cosmetics and personal care products in the UK, after a long-promised ban came into effect on Tuesday. The ban initially bars the manufacture of such products and a ban on sales will follow in July. (…) (, 9/01/2018)

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Microplastics releasing from personal care and cosmetic products in China

Microplastics (MPs) have become a major global issue; their release from various products affects the aquatic environment, especially marine ecosystems. As a primary source of MPs, personal care and cosmetics products (PCCPs) containing MPs contribute to this environmental risk. We visited several supermarket chains in Beijing, China to identify PCCPs containing MPs. Overall, 7.1% of facial cleansers contained MPs, with an average weight of 25.04 ± 10.69 mg MP/g and average size of 313 ± 130 μm; whereas, 2.2% of shower gel products contained an average weight of 17.80 ± 7.50 mg MPs/g with an average size of 422 ± 185 μm. The majority of MPs were made of polyethylene, based on Raman and Fourier transform-infrared spectra analyses, while only a few were made of walnut shells and carbon particles. Finally, estimated 39 tons MPs were released into the environment based on PCCPs use in China based on available data.

Kun Lei, Fei Qiao, Qing Liu and al., Marine Pollution Bulletin, Available online 11 September 2017, In Press

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Are There Nanoplastics in Your Personal Care Products?

Fragmentation of plastic debris and the commercial use of plastic microbeads have led to the widespread distribution of microplastics in natural environments. Several studies have reported on the occurrence and toxicity of microplastics in soils and waters; however, due to methodological challenges, the presence and impact of nanoplastics (<100 nm) in natural systems have been largely ignored. Microbeads used in consumer products such as scrubs and shampoos are processed by mechanical means that may lead to their fragmentation into potentially more hazardous nanoplastics. In this study, three commercial facial scrubs containing polyethylene microbeads (~0.2 mm diameter) were examined to verify whether they contained nanoplastics. Particulates in the scrubs were fractionated using sequential filtration to isolate particles smaller than 100 nm. Scanning electron microscopy was used to confirm the presence of nanoparticles ranging in size from 24 ± 6 nm to 52 ± 14 nm. X-ray Photoelectron Spectroscopy and Fourier Transform Infrared Spectroscopy were used to confirm that the identified nanoparticles consisted of polyethylene. This study confirms the (unexpected) presence of nanoplastics in personal care products containing polyethylene microbeads and highlights the need for further studies to characterize the release and distribution of nanoplastic litter in natural aquatic and soil environments.

Laura M. Hernandez, Nariman Yousefi, and Nathalie Tufenkji, Environ. Sci. Technol. Lett., 2017, 4 (7), pp 280–285

Characterisation of plastic microbeads in facial scrubs and their estimated emissions in Mainland China

Plastic microbeads are often added to personal care and cosmetic products (PCCPs) as an abrasive agent in exfoliants. These beads have been reported to contaminate the aquatic environment and are sufficiently small to be readily ingested by aquatic organisms. Plastic microbeads can be directly released into the aquatic environment with domestic sewage if no sewage treatment is provided, and they can also escape from wastewater treatment plants (WWTPs) because of incomplete removal. However, the emissions of microbeads from these two sources have never been estimated for China, and no regulation has been imposed on the use of plastic microbeads in PCCPs. Therefore, in this study, we aimed to estimate the annual microbead emissions in Mainland China from both direct emissions and WWTP emissions. Nine facial scrubs were purchased, and the microbeads in the scrubs were extracted and enumerated. The microbead density in those products ranged from 5219 to 50,391 particles/g, with an average of 20,860 particles/g. Direct emissions arising from the use of facial scrubs were estimated using this average density number, population data, facial scrub usage rate, sewage treatment rate, and a few conservative assumptions. WWTP emissions were calculated by multiplying the annual treated sewage volume and estimated microbead density in sewage. We estimated that, on average, 209.7 trillion microbeads (306.9 tonnes) are emitted into the aquatic environment in Mainland China every year. More than 80% of the emissions originate from incomplete removal in WWTPs, and the remaining 20% is derived from direct emissions. Although the weight of the emitted microbeads only accounts for approximately 0.03% of the plastic waste input into the ocean from China, the number of microbeads emitted far exceeds the previous estimate of plastic debris (>330 μm) on the world’s sea surface. Immediate actions are required to prevent plastic microbeads from entering the aquatic environment.

Pui Kwan Cheung, Lincoln Fok, Water Research, Volume 122, 1 October 2017, Pages 53–61

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Government drops opposition to Bill banning microplastics

The Government has reversed a decision to oppose a Labour Party Bill banning the use of microplastics and microbeads in personal care items including scrubs, soaps, lotions and toothpastes.

Minister for Housing Simon Coveney had originally planned to reject the Prohibition of microplastics Bill on the grounds that it could place Ireland in breach of EU Treaty articles on the free movement of goods and that it was flawed in definitions, enforcement and its “level of ambition”.

But in the Dáil on Thursday he told the Bill’s author, Cork East Labour TD Seán Sherlock, that the Government would not oppose the legislation but would probably abstain and allow it to proceed on the basis that “if and when we produce the Government’s legislative response to this whether in the foreshore Bill or in a separate piece of legislation after the work that needs to be done first”. (…) (, 4/05/2017)

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