BFU physicists developed a method of determining the composition of microplastic in water

January 21, 2019

Physicists from Immanuel Kant Baltic Federal University developed and applied a method of identifying microplastic collected in sea waters. The spectroscopy method allows to determine the chemical composition of contaminants regardless of their size. The article about the research was published in Marine Pollution Bulletin.

All plastic that gets into sea waters stays in the sea. It does not disintegrate, only granulated. This way it becomes even more dangerous for marine animals and fish as it easily gets into their body with water and food and is accumulated in the organs. Moreover, microplastic is difficult to catch. It is impossible even to measure the exact tonnage of plastic in the ocean. Collecting it from the surface with nets is not enough, as microparticles often travel from one water layer to another. The existing tools for deep plastic collection are, as a rule, unable to identify the depth at which a sample was taken, and without the information on the distribution of microplastic in different water layers it is impossible to understand how the pollution spreads in the ocean and what the current volume of it is. Even when the samples are collected, scientists still find it difficult to determine the chemical composition of small polymer particles.

A new method for determining the composition of microplastic was suggested by physicists. They identified the particles collected in the Baltic Sea using a new device called PLEX PLastic EXplorer). It has been developed by the physicists of the Northern Water Problems Institute at Karelian Research Centre of the Russian Academy of Sciences together with the Atlantic Department of Shirshov Institute of Oceanology of the Russian Academy of Sciences. The device has a pump able to pump up 2-3 m3 of seawater at any depth up to 100 meters. The water is transported to a ship where all solid particles are filtered from it. Pumps are manually added to the filtration system and washed before sample collection, and filters are changed manually as well. Therefore PLEX should have at least two operators, one to monitor the pump, and one to take care of the filter.

Using the new device the researchers collected microplastic samples from different levels of the Baltic Sea. Additional samples were gathered manually at the shore. The samples underwent detailed study, and the final stage of the analysis was the identification of their chemical composition. Such fragments and threads are incredibly small (e.g. the diameter of the fibers and fragments is 50 micron or less), therefore their analysis requires a very sensitive methodology. BFU physicists developed a method based on Raman scattering spectroscopy. Different substances inelastically scatter light in a different way, and the developed method helped understand the elements of each sample. The scientists found 33 types of contaminants in the samples from the Baltic Sea, including nylon, polyethylene, cellulose, polypropylene, and so on.

"Spectral analysis of microscopic polymeric particles is a difficult task. The fluorescence of the dyes in coloured polymers (that are most widely-spread) is a considerable issue. The polymer and the dye have a strong bond, and one has to create specific experimental conditions to minimize the fluorescence of the dye and at the same time to identify the polymer's signal in the spectrum. In several cases microscopic samples required additional purification and multicomponent spectral analysis to break complex spectrums (e.g. those containing several polymers and a dye) into separate parts. As a result we've developed a method allowing us to clearly identify the chemical composition of the samples. It turned out to be quite useful for applied research of marine physics," says Andrey Zyubin, a senior research associate at the Scientific and Educational Center of BFU "Fundamental and Applied Photonics. Nanophotonics".

Immanuel Kant Baltic Federal University

Related Water Articles from Brightsurf:

Transport of water to mars' upper atmosphere dominates planet's water loss to space
Instead of its scarce atmospheric water being confined in Mars' lower atmosphere, a new study finds evidence that water on Mars is directly transported to the upper atmosphere, where it is converted to atomic hydrogen that escapes to space.

Water striders learn from experience how to jump up safely from water surface
Water striders jump upwards from the water surface without breaking it.

'Pregnancy test for water' delivers fast, easy results on water quality
A new platform technology can assess water safety and quality with just a single drop and a few minutes.

Something in the water
Between 2015 and 2016, Brazil suffered from an epidemic outbreak of the Zika virus, whose infections occurred throughout the country states.

Researchers create new tools to monitor water quality, measure water insecurity
A wife-husband team will present both high-tech and low-tech solutions for improving water security at this year's American Association for the Advancement of Science (AAAS) annual meeting in Seattle on Sunday, Feb.

The shape of water: What water molecules look like on the surface of materials
Water is a familiar substance that is present virtually everywhere.

Water, water everywhere -- and it's weirder than you think
Researchers at The University of Tokyo show that liquid water has 2 distinct molecular arrangements: tetrahedral and non-tetrahedral.

What's in your water?
Mixing drinking water with chlorine, the United States' most common method of disinfecting drinking water, creates previously unidentified toxic byproducts, says Carsten Prasse from Johns Hopkins University and his collaborators from the University of California, Berkeley and Switzerland.

How we transport water in our bodies inspires new water filtration method
A multidisciplinary group of engineers and scientists has discovered a new method for water filtration that could have implications for a variety of technologies, such as desalination plants, breathable and protective fabrics, and carbon capture in gas separations.

Source water key to bacterial water safety in remote Northern Australia
In the wet-dry topics of Australia, drinking water in remote communities is often sourced from groundwater bores.

Read More: Water News and Water Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to