WC137 JulyAug 2024 - Magazine - Page 33
Plastics found in places
without human activity
Of the nine lakes studied, none were free
of microplastics. Regardless of the level
of activity on the lake, and the extent of
human access measured, plastics were
found in every single lake tested. There
was no pattern whereby lakes with more
human activity had more microplastics,
suggesting that local human activity was
not the source of the pollution.
Moreover, microplastics were found
in the atmospheric deposition samples,
suggesting the source may be via the air.
The researchers believe the majority of
the plastics found in these remote lakes
came through atmospheric deposition.
This is because the plastics found in the
air above the lake had microplastics that
were of a similar composition to those
found in the lake.
As surprising as these findings may
seem, they are relatively aligned with discoveries of plastics in some of the globe’s
most remote areas—from freshly-fallen
snow in the Antarctic to the clouds above
Mount Fuji.
Getty Images
A study conducted at Canada’s IISD Experimental Lakes Area found plastics in
each of the nine lakes tested. Remote lakes that saw little human activity saw
similar levels of plastic waste as lakes more easily accessed.
The researchers selected nine lakes in that area as part of their
preparation for a larger project. Three of these lakes were lightly
visited by humans, and only for research. Three were used for
research often, and thus had moderate human activity. The final
three lakes were used for recreation by the public as well as research. Although these three had the greatest amount of human
activity, their activity was much lower than in urban areas.
To understand how much microplastics were at IISD-ELA,
the team sampled the surface water of all nine lakes. They also
sampled the sediment in some of them, as well as the atmospheric
deposition around them to help determine how the plastics ended
up there in the first place, whether through direct inputs (point
source) or through the air (atmospheric deposition). In every sample, every piece of microplastic was tediously counted, measured,
and chemically analyzed to determine the material type.
WAT E R C A N A D A . N E T
Where does the research go from here?
Going forward, it seems clear that more
monitoring and testing of lakes across
the world—even in remote and semi-remote areas—is critical to
work out through which sources and pathways plastics pollution
is entering freshwater bodies, and, ultimately, to determine the
best ways to mitigate that contamination.
For the pELAstic project, the research continues. After two
summers of work using in-lake mesocosms that separate a
segment of the water column from the rest of the lake, they are
currently in the ‘whole-ecosystem’ phase of their research. At this
moment, the team is gearing up for a second year of microplastic
additions into a whole lake back at IISD Experimental Lakes
Area in an attempt to answer all manner of questions regarding
the fate, movement, and impacts of microplastics pollution within freshwater lakes.
As always, however, the results of this work are not destined
to end their journey on a dusty shelf. The ultimate goal is to take
the findings and translate them into sound and evidence-based
policy recommendations in Canada and around the world, as the
campaign to protect the environment and our precious freshwater resources from the scourge of freshwater pollution continues
to intensify.
WATER C AN ADA • JULY/AUGUS T 2024
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