Monday, 30 March 2026, 8:39 pm
Article: Independent Media Institute
Microplastics, plastic particles smaller than 5
millimeters, can be found in land, air, and water, and have
infiltrated our food chain, resulting in far-reaching health
consequences for humans and nonhumans alike. In 2020, scientists
discovered the “highest level of microplastic ever
recorded on the seafloor,” revealing the extent of their
impact on the marine ecosystem.
The lead author of the
study, Ian Kane from the University of Manchester, said:
“Almost everybody has heard of the infamous ocean
‘garbage patches’ of floating plastic, but we were
shocked at the high concentrations of microplastics we found
in the deep-seafloor.”
These microplastics enter the
marine ecosystem directly and indirectly, for example, from
landfills, where they are carried by wind into rivers and
seas. “It is estimated that 8 million tonnes of plastics
enter the seas and oceans each year,” stated
a 2021 study published in MDPI.
Mussels can act as
sentinels to assess and monitor microplastic pollution.
Globally distributed in both freshwater and saltwater
ecosystems as filter feeders, mussels are both sensitive to
environmental pollution and play a key role in engineering
aquatic ecosystems by processing huge quantities of
water.
With serious concerns about microplastic
contamination of food, particularly
seafood, and human bodies growing, mussels will
inevitably serve as an increasingly
important bioindicator of microplastic pollution from
the present into the future.
The Impacts of Plastic
Disintegration
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Manmade, fossil fuel-based plastics
don’t biodegrade like natural materials; instead, they
break up into increasingly tiny plastic particles. Scientists
categorize these particles by size: those 5–10
millimeters are called “mesoplastics,” those between 1
nanometer and 5 millimeters (about the diameter of a pencil
eraser) are called “microplastics,” and those 1
nanometer (a human hair is 80,000-100,000
times nanometers wide) and smaller are
“nanoplastics.” While nanoplastics are too small to be
seen, microplastics and mesoplastics are fairly
visible.
Microplastics that are “intentionally
produced” for inclusion in cosmetics or exfoliating
products, such as soap scrubs and toothpastes, are typically
manufactured as tiny beads or flat pieces of glitter. These
ready-made microplastics are called “primary”
microplastics. Primary microplastics also include
nurdles—small pellets of plastic melted down into the
plastic products we are familiar with. Nurdles are often
discharged into waterways through industrial
wastewater runoff from plastic production facilities,
and during shipping
fires and spills from cargo ships. About 445,970
tons of nurdles are estimated to directly pollute the
environment globally every year, especially aquatic
ecosystems.
Plastic particles that form due to the
disintegration of plastic materials are called “secondary”
microplastics. These particles may be pieces of plastic
film, fibers (from textiles and rope), foam, hard or soft
fragments, and lines (such as from fishing gear). They break
down from plastic packaging, synthetic textiles, paint, and
other plastic materials used in our homes. Plastic’s breakdown
is accelerated by sunlight, extreme temperatures,
exposure to bacteria, fungi, and water, and by
weathering.
These particles were first documented in
marine ecosystems in the early 1970s
and have since been found in indoor and outdoor air,
drinking water, fresh and processed foods, fresh waters,
household dust, plants and trees, oceans, soils, and in
animals—including humans.
Plastics are not only
harmful to our health but also impose significant economic
costs. “Estimates suggest that plastic pollution causes
about $75 billion per year in environmental damages, with
$13 billion of this tied to marine ecosystems. For example,
plastic pollution can deplete fish stocks and impact coastal
tourism by littering popular beaches. It can damage
infrastructure like urban drainage systems. It can even
de-operationalize or sink ships by entangling propellers or
clogging water intake systems responsible for cooling their
engines,” pointed
out the World Resources Institute.
Microplastics
Threaten Marine Life
While plastic particles have
virtually contaminated the entire Earth due to their
constant movement through the biosphere, marine ecosystems
in particular are a major repository for mesoplastics,
microplastics, and nanoplastics. Freshwater systems empty
into the oceans, and populous
coastal areas—especially those that have been
industrialized—are major sources of microplastic pollution
in marine ecosystems. About
80 percent of plastics in the oceans are estimated to
have traveled there via rivers and other freshwater systems.
Flooding
and weather events can push microplastics into rivers in
significant quantities.
A 2021 report
by the UN Environment Program (UNEP) stated that plastic
accounts for 85 percent of marine litter, and by 2040, we
can expect the volume of plastic pollution to nearly triple
if we don’t take preventative measures.
Fish and
other marine animals are exposed to microplastics in waters
and sediments, from the sea surface to the seafloor. Many
animals, including some fish
species that people eat, consume nurdles and other round
microplastics because they resemble their usual food
sources, such as fish eggs and other plankton. Some fish
species and marine animals are attracted
to the smell of weathered plastic particles. Even
relatively small amounts of plastic can be deadly to marine
wildlife. For example, a 2025 study
in the Proceedings of the National Academy of Sciences
suggests consuming the equivalent volume of less than one
sugar cube of plastic can kill one in two Atlantic puffins;
less than half a baseball’s size in plastics can kill one
in two Loggerhead turtles; and the amount of plastic in less
than a sixth of a soccer ball can kill one in two harbor
porpoises.
Microplastic consumption has been linked to
adverse health effects in marine animals, including mussels.
“Circulatory system of fish is impacted by the
microplastic bioaccumulation in their tissues, influencing a
number of hematological indices that are connected with
immunity, osmotic pressure, blood clotting, molecular
transport and fat metabolism,” stated a 2024 study
in Toxicology Reports. Microplastics and plastic chemicals
have also been linked
to gastrointestinal blockages, neurological
issues, starvation, toxicity, and reproductive issues in
marine life.
Filter feeders, including mussels,
have limited abilities to sort and reject plastic particles
as they siphon water for food. Mussels
pull in about one-fourth cup of sea water per minute, a
huge volume for a small animal. Studies have shown mussels
from different regions with varying
quantities and types of microplastics in their soft
tissues and digestive systems. Mussels and other
filter-feeding shellfish ingest greater
amounts of microplastics than other marine creatures.
Like other pollutants, microplastics bioaccumulate
up the food web, concentrating inside the bodies of
predators as they consume prey.
Ingestion of polyester
plastic fibers has been shown to stunt
the growth of young blue mussels by more than one-third.
Smaller mussels with lower growth rates and stressors like
inflammation
can reduce the survival of mussels, and thus the overall
availability of food sources for animals that prey on them,
from birds to crabs, starfish, whelks, and, of course,
people. Microplastics have also been linked to cellular
and molecular damage in mussels.
What’s more, chemicals commonly
manufactured into plastics, such as heavy
metals, phthalates,
and PFAS,
have also been shown to bioaccumulate
in the marine food web.
Marine Microplastic Pollution
Raises Human Health Concerns
Microplastics have been
detected
throughout the human body, in people’s
bloodstreams,
bones, bone marrow,
brains,
breast milk,
urine and feces of adults and infants,
hair,
hearts,
kidneys,
livers,
lungs,
penises,
placentas,
saliva and sputum,
semen,
skin,
spleens,
stomachs,
testes, throat
and airways,
uteruses, and
veins.
The presence of microplastics in people has
been linked to
Alzheimer’s disease, dementia
(in mice),
Parkinson’s disease, and other neurodegenerative
disorders; inflammation,
heart attack, stroke, and death; they have been found in
samples of
bladder cancer; and are suspected to harm
human fertility and reproductive health. Exposure to
microplastic particles is also linked to
cell damage and death.
Exactly how and why
microplastics cause harm is under investigation. But
scientists do know that microplastic particles can contain
any number of 16,000 plastic
chemicals, at least 4,200 of which have already been
linked to adverse human health effects, including causing
cancer and disrupting
hormones.
In fish, microplastics tend to accumulate
in the gills and digestive system, so it would seem that
eviscerating fish before human consumption would minimize
exposure. However, gilling and gutting fish does
not necessarily eliminate microplastics. What’s more,
some seafood, including some bivalves, crustaceans, and
oilfish like sardines, are typically eaten whole, and it’s
not always possible or practical to excise microplastic
hotspots in their bodies. Seafood may contain more
microplastics during
certain seasons due to changes in ocean currents,
rainfall and runoff, flooding, and other factors that
increase pollution.
“Researchers estimate that
adults in the United States may ingest nearly 4 million
microplastic particles per year from protein sources
alone,” stated
EarthDay.org.
Scientists are still determining the
full range of risks linked to human consumption of
microplastics. Recommendations
on the frequency and type of seafood consumption, based on
age, sex, and pregnancy status, currently exist in the United
States and Europe
to minimize exposure to chemicals like PCBs and mercury.
However, pollutants on which such guidelines have been
developed do not necessarily include
microplastics.
The Way Forward
The fact that
seafood—and other major sources of nutrition, including fresh
fruits and vegetables—are increasingly polluted with
microplastics is a serious concern for human health.
Billions of people around the world depend on seafood as a
key source of nourishment (not to mention their
livelihoods).
Scientists continue to search for
microplastics inside the flesh, gills, and guts of marine
animals eaten as seafood, including mussels. Researchers
have found microplastics in
all of the most-eaten mussel species purchased from
markets, with an average of 0.13 to 2.45 microplastic
particles per gram of mussel meat. The most contaminated
organisms were found in the North Atlantic and South
Pacific. In another 2024 study, researchers found that 99
percent of seafood samples purchased in stores and
collected from fishing vessels on the U.S. West Coast
contained microplastics, with shrimp being the most
contaminated type of seafood studied.
The study and
understanding of how microplastics affect food safety is
still in its “infancy.” Advanced analytical methods can
help ensure more accurate detection of microplastic levels
in certain foods, thereby enhancing monitoring. Governments,
meanwhile, need to step up regulations and ensure
“specific practices in food production, processing, and
packaging to minimize the introduction and spread of
microplastics,” according
to an article in Smart Food Safe. Greater Industrial and
international cooperation to address the issue can lead to
consistent standards to make the food chain safer from
microplastics. Moreover, “Regularly updating methodologies
and standards based on new scientific findings ensures that
strategies remain effective and aligned with the latest
knowledge,” added the article.
California is leading
the U.S. in monitoring microplastics in the marine
environment. In 2022, it established its Statewide
Microplastics Strategy, focusing on identifying
microplastic pollution trends, risks, and sources. Academics
continue to focus on monitoring microplastics, increasingly
in sentinel species like mussels, often with the help of
community scientists.
Mitigating Plastic Pollution
Needs to Start at the Source
Pressure
from consumers and strong policies, such
as bans and taxes on single-use plastic products, can help
eliminate plastic that inevitably breaks down into secondary
microplastics. These actions are necessary to force
businesses to move away from plastic and adopt
plastic-free practices and products. Other laws, like the
European Parliament’s 2025 legally
binding regulation implementing mandatory prevention
measures relating to “pellet loss” and the U.S. Microbead-Free
Waters Act of 2015, which “prohibits
the manufacturing, packaging, and distribution of rinse-off
cosmetics containing plastic microbeads,” further help
address the issue of primary sources of microplastic
pollution upstream.
Litigation is also another tool
utilized by communities and organizations to hold polluters
accountable. Some cases successfully
target downstream pollution resulting from
microplastics. Others are working to address
longstanding systemic issues like racism that perpetuate
the unjust targeting of underserved communities as
“sacrifice zones” for industrial polluters. While some
others are challenging
polluters’ use of false and misleading marketing
claims around their plastic products labeled as
“sustainable” or “healthy.”
The key to
mitigating plastic pollution is starting at the source, with
fossil fuel extraction and plastic production. Ultimately,
society needs to shift its reliance on fossil fuels and
plastics toward safe, plastic-free reuse and regenerative
solutions at a systemic level.
Plastic recycling is
not a solution in and of itself; it actually can perpetuate
plastic production and requires virgin (new) plastic and
plastic additives, as plastic diminishes in quality with
each round of recycling.
“Fossil fuel and other
petrochemical companies have used the false promise of
plastic recycling to exponentially increase virgin plastic
production over the last six decades, creating and
perpetuating the global plastic waste crisis and imposing
high costs on communities that are left to pay for the
consequences… As of 2021, the U.S. recycling rate for
plastic is estimated to be only 5-6 percent,” according
to a 2024 report by the Center for Climate
Integrity.
Plastic and fossil fuel corporations have
long pushed recycling as a solution to plastic pollution,
when in reality, ceasing plastic production is the core
solution. Inevitably, some recycling may be required in the
future to address the plastic already in circulation, but
recycling practices might be improved to prevent further
harm. Similarly, while cleanups cannot solve the problem,
they will inevitably be needed in the future to reduce the
risks posed by microplastics.
Microplastics are a
systemic pollution problem requiring a coordinated
global response, such as a strong Global
Plastics Treatythat addresses plastic pollution
throughout its toxic life cycle. While negotiations on the
treaty continue,
countries need to take steps to reduce plastic production
and use, and consumers need to make better choices to drive
change at the individual level. These steps are necessary to
mitigate the damage already caused by the unchecked plastic
use and to ensure a more sustainable
future.
Author Bio: Erica
Cirino is a writer, artist, and author who explores the
intersection of the human and more-than-human worlds. Her
photographic and written works have appeared in Scientific
American, the Guardian, VICE, Hakai Magazine, the Atlantic,
and other publications. She is a recipient of fellowships
from the Woods Hole Oceanographic Institution, the Craig
Newmark Graduate School of Journalism at CUNY, and others,
as well as several awards for visual art. She is a
contributor to the Observatory.
This
article was produced by Earth
| Food | Life, a project of the Independent Media
Institute.
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