Oh! Scientists can contaminate their samples with microplastics

Water sampling from the Hudson River. Credit: Adam Glassy

More than 70% of the microplastics found in samples from oceans and rivers can be obtained from the scientists who collect them.

Do scientists contaminate their own samples? Research shows that we can emit microfiber clouds.

A paper by Staffordshire University and the Rozalia Project, published in Bulletin on Marine Pollution, investigates procedural contamination during microparticle sampling in an aqueous medium. The study shows that a significant amount of microplastics and microfibers from scientists ’clothing and equipment are mixed with environmental pollution in water samples.

Claire Gwyneth, a professor of forensics and environmental science at Staffordshire University, explained: “In this area, this may be due to the dynamic nature of the environment, such as wind or weather, the actions required to obtain samples, and proximity. needed by scientists to acquire and provide samples on a medium-sized vessel, on a small vessel, or by sampling from shore. In the mobile lab, this is often due to the use of small multifunction rooms and similar requirements for scientists to be in close proximity to samples during processing. ”

The data was collected during an expedition on the Hudson River from the 60-foot oceanographic research vessel of the Rozalia project, the American Promise. The team tracked pollution by collecting fibers from all possible sources of pollution on the ship, including clothing worn by both scientific and boat crews, sailing bags and tarpaulins, sails and equipment control lines, and indoor textiles. In this way, they created a catalog in which each fiber and fragment found in environmental samples was first compared. If there was a coincidence, the exact source of procedural pollution was noted. If there was no match, this microparticle was considered contaminant.

Sampling from the Hudson River

Collect samples from the Hudson River by American Promise. Credit: Rachel Z. Miller

The study found that when robust pollution control protocols were not used in water sampling (using a metal bucket for surface samples and a Niskin bottle for mid-column water samples), 71.4% of the microparticles in the samples were contaminated; similarly, when anti-pollution protocols were not used in the treatment of water samples (using the vacuum filtration method), 68.4% of the microparticles in the samples were contaminated.

Co-author Rachel Z. Miller, founder of the Rozalia Clean Ocean Project, said: “This is a study that was designed to strengthen the scientific process and showed the extent to which our clothes shed, not just in the washing machine or dryer, but how we do it. wear and behave in daily life. It looks like we’re all Pigpen, but instead of walking in a cloud of dirt, we can release clouds of microfiber.

“Some conclusions for ordinary people from this study: take care of the clothes we have – this can be done by adapting washing procedures to reduce fiber breakage, such as washing in cold water and air drying if possible; given the clothes we choose – there is more and more information about how different types of fabrics are shedding, and supporting brands and organizations that know about the problem and solve it, working to better understand our textiles and who use innovations to make them more resilient and from materials that put less pressure on our natural world while maintaining their ability to protect us from the elements ”.

The study also outlines methods inspired by forensic science that could reduce by 37% the amount of procedural contamination mistakenly added to environmental samples at the research collection stage. This reduction can save research teams a significant amount of time by reducing the number of microparticles that need to be analyzed.

Solutions for future research include outfitting the entire team in uniform clothing of an unusual color, ideally also with an unusual fiber morphology. This will allow you to quickly identify the contamination. It is important that the entire boat crew was included in these quality control considerations, as fibers from the captain and first mate were also found in the samples during this study.

Researchers are also describing a workflow using a polarizing light microscope (PLM) that can save research teams both time and money if it is necessary to identify microparticles, particularly microfiber. Coupled with Easylift® tape, an innovation used to sample and fix microparticles after vacuum filtration, this study found that PLM can provide high confidence / correct material identification in 93.3% of microfibers found in water samples. PLM can cost less than $ 4,000 and take less time compared to other methods.

Professor Gwyneth added: “As this study has shown, thinking like a forensic pathologist during microplastic sampling has its advantages. Forensic experts are constantly thinking about how they can contaminate samples and how to prevent it. Forensic experts also recognize that zero pollution cannot be achieved, and instead focus on creating protocols to minimize and control.

“Using forensic analysis techniques that aim to fully profile a particle, including its morphological, optical, and chemical characteristics, these“ layers ”of information allow us to draw much more confident conclusions as to whether it is an environment or from procedural contamination. ».

Help: “Are we contaminating our samples? Preliminary study on the study of procedural contamination during sampling and processing of field samples for microplastics and anthropogenic microparticles ”C. Gwinnett and RZ Miller, November 9, 2021, Bulletin on Marine Pollution.
DOI: 10.1016 / j.marpolbul.2021.113095 Oh! Scientists can contaminate their samples with microplastics

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