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August 18, 2019
THE THREAT TO LIFE FROM OCEAN MICROPLASTICS
Meena Miriam Yust and Arshad Khan
When Chelsea Rochman at the University of Toronto and colleagues began their
study on medakas (small Japanese rice paddy fish), they did not expect to find what
They first soaked ground-up polyethylene in San Diego Bay for three months and
then fed it to these fish along with a laboratory diet. They also fed the same diet to a
comparison group of medakas but along with virgin polyethylene also ground-up. The
medakas eating the plastic immersed in the Bay suffered greater liver damage. How
much of a danger then is our seafood?
Defined as less than 5mm in size, microplastics have been found in 114 types of
aquatic life, over half of which are consumed by humans. Oysters exposed to
food-container plastic (polystyrene) have fewer eggs and impaired less-motile sperm.
Does eating them do the same to us? Nobody knows. A comprehensive study of
plastics in seafood and its implications for human health points to the gaps in our
knowledge. It calls for more research into the toxicity of various plastics and in
identifying lower risk seafood.
There is some evidence for the quantity of microplastic pieces per cubic meter of
water -- from the surface to a depth of 1000 meters in one study. The numbers range
from four pieces at the surface increasing to about a dozen at 200 meters down then
declining to three or so at a 1000 meters down. It is certainly not super dense. At the
same time, little fish ingesting it and bigger fish eating smaller ones, and one can see
a problem developing, particularly for us the final consumer.
The copious plastic debris flowing into the ocean estimated at 8 million tons annually
continues to add to the 100 million tons already there. Engineering experts at
Stanford University have discussed "the potential for meaningful change" in the status
quo. They have some interesting observations: Microplastics are now in "about a
quarter of the sea foods in our markets and even in table salt." They are also in "94
percent of tap water samples in the US and in nearly every brand of bottled water." At
this we checked tap water and some bottled water and did not notice any. Insidious, if
these are microscopic.
Research in other parts of the world exemplify the global extent of the microplastics
menace. In a study of commercial fish caught off the Portuguese coast, microplastics
were found in 19.8 percent of the 26 species of fish tested. Plastic polymers,
polyethylene and polypropylene as well as fibers like polyester, rayon and nylon had
been ingested. As might be expected, the fish taken off Lisbon and its environs were
In another study, fish and bivalves taken from markets in California and Makassar,
Indonesia were examined for anthropogenic debris. Plastic was again confirmed in
seafood sold for human consumption. Debris was found in about a quarter of
individual fish and a third of shellfish raising concerns about human health.
North Sea fish have been studied for plastic ingestion also. Foekema and his fellow
researchers found particles up to 4.8 mm in five of seven common North Sea fish
species. Usually only one particle was found and in only 2.6 percent of the 1204
individual specimens tested. Cod showed the highest frequency with one third
involved. In another study of 400 individual fish from four species, only two particles
were found, both in one individual, a sprat, confirming the relative low incidence of
plastics in North Sea fish. The particles in the sprat were microbeads.
Then there is the ubiquitous cigarette butt. Is there something prophetic about
dropping and stubbing it as the final act of a habit statistically known to shorten the
lives of smokers? Discarding butts may be socially acceptable but when 6.5 trillion
cigarettes are smoked each year around the world, and an estimated two-thirds of the
ends flicked away carelessly, butts become the most littered plastic item. Made of
cellulose acetate they degrade slowly, and then into tiny microplastic pieces finding
their way often into waterways and oceans.
The thrown-away butt, a lethal parcel of absorbed nicotine, heavy metals and
chemicals, appears to marine life as food floating on the surface. It has been found to
be deadly to fish, and to inhibit plant growth. A new addition, e-cigarettes are growing
in popularity, their discarded pods posing a similar problem -- not to mention the
e-cigarette itself, a package of plastic, electric circuitry and battery.
Another disturbing trend is for manufacturers to add plastic microbeads as cheap
fillers in household products like toothpaste, shampoo and cosmetics. Washed down
the drain, and small enough to bypass the water filters at reclamation plants, these
eventually find their way into the ocean. Of course some can be swallowed
accidentally by product users. A Mother Jones (May 28 , 2015) article pictures an
array of products containing them.
Fish are fooled by microbeads which are a similar size and shape to fish eggs. Add
all the other plastics and the chemicals adhering to them and they become a meal
with long-term consequences for other predators as well. The Guardian newspaper
reports on five species affected by ocean plastics. Fish-eating birds, whales with
plastic-clogged stomachs, turtles snagged by plastic six-pack holders, crabs ingesting
microplastics that also enter through their gills, even vital oxygen producing ocean
bacteria are being harmed.
Birds eating plastic had stunted growth and kidney problems noted a University of
Tasmania study with particular reference to the near-threatened flesh-footed
shearwaters (long-winged oceanic birds). They have estimated a million seabirds
dying annually from plastic ingestion, and other researchers have tagged balloons as
the "no.1 marine debris risk of mortality for seabirds." A high-risk item, ingesting a
balloon fragment is 32 times more likely to cause death than a hard plastic item.
A map of the US showing the interest levels in plastic pollution for the different states
as measured by the numbers of tweets about the subject might be appropriate in our
new world of politics by tweet led by the president. None of it helps the individual
dying of kidney, liver or pancreatic cancer. Infertility clinics abound as sperm counts
decline in the west and specially in the US ... joining the oysters mentioned earlier.
If we reflect on the issues, a logical answer emerges; that is, to reduce plastics, ban
single-use items, increase recycling, and dispose of the rest safely. Above all,
educating us remains key. Who knew cigarette butts are not just an unsightly
nuisance but deadly?
Meena Miriam Yust is an attorney based in Chicago, IL with a special interest in the
Arshad M. Khan is a former professor who has, over many years, written occasionally
for the print and often for online media outlets.