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INNOVATION
Detecting Nanoplastics in Water
Canadian researchers lead the world with AI-based solutions BY TREENA HEIN
ANOPLASTICS represent an extremely
serious global water quality problem, one
that is getting worse by the day. According to
the United Nations, 11 million metric tons
of plastics enter the Earth’s aquatic systems
each year, with 200 million metric tons of plastic
waste already present. As this volume of plastic pollution increases in the world’s oceans, it is continually
degraded by microbial enzymes to eventually become
micro- and nano-sized plastic particles. As noted
recently by a team of Malaysian scientists, these substances are now present in enormous quantities in the
marine environment.
In addition, these scientists point out that due
to their wide bioavailability and ubiquity in both
aquatic and terrestrial areas, it is highly probable that
micro/nanoplastics are present in many food products. Already, they note that micro/nanoplastic fragments have been detected in honey, beer, salt, sugar,
fish, shrimps and bivalves, as well as tap, bottled and
spring waters.
Due to the tiny size of these particles, removal
strategies have not come easy. Readers of Water Canada will recall that in our August issue, we introduced
you to a team of researchers based at University of
Waterloo that is leading the world in removing nanoplastics from wastewater systems.
However, another Canadian team is leading the
world in nanoplastic detection, using an innovative
holographic and artificial intelligence (AI) approach.
According to the Principal Scientist Parisa Ariya,
Professor in the Departments of Chemistry and
Atmospheric & Oceanic Sciences and Director of the
Atmospheric & Interfacial Chemistry Laboratories at
N
Treena Hein is an award-winning
freelance science and technology writer
based in eastern Ontario.
WAT E R C A N A D A . N E T
McGill University in Montreal, this technology “has
the potential to revolutionize how we monitor and
manage plastic pollution.”
A new direction
Up to this point, although they are described as ”excellent” by Ariya, existing detection methods for micro/
nanoplastics have not been very effective in helping
determine the impact of nanoplastics in ecosystems
(for various reasons, one big one being the immediacy of test results). For example, her own group has
developed a highly-successful laser-mass spectrometry
detection method. “This cutting-edge approach has
enabled us to achieve a remarkable feat of a detection
limit of 5 picograms,” she explains. “We have confidently demonstrated the effectiveness by detecting
nano/microplastics in snow in Montreal.”
At the same time, however, Ariya and her colleagues
foresaw the necessity to go in a new and more useful
detection direction. “We knew,” she says, “that we
must do it in real-time and in-situ if we wanted to
look at life cycle analysis or toxicology of nano/microplastics, and to provide physicochemical characterization.”
Over about four years, Ariya and her team (in
collaboration with the National Research Council of
Canada) pursued the development of their entirely
unprecedented and innovative platform, and have
realized success. Their AI-assisted nano digital in-line
holographic microscopy (DIHM) system automatically distinguishes micro/nanoplastics simultaneously
from non-plastic particles within milliseconds, in both
stationary and dynamic natural waters, and without
any sample preparation – even when these plastics are
coated in other particles.
It is a world first of which they are rightly very
proud, having solved thorny optics problems, developed a unique real-time capability to analyze sub-100
nanometer particles and also achieved full automation
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