Monday, October 7, 2019
Perils of Microplastics
While the world focuses on
environmental damage we can see and feel directly – heat, floods and storms
from global climate change or massive accumulations of garbage on the
land and in the sea – there is another massive pollution source that isn’t so
visible but carries lots of health threats too: microplastics. We are just
beginning to explore the impact of these particles, many of which are so small
that they find their way in our drinking water, even after filtration. Or show
up in our food chain. In short, most of us are walking around with significant
deposits of microplastics in our bodies. Because there are a variety of such
tiny pollutants, there is no uniform medical reaction to them. While much of
those microplastics pass through the human (and animal) body, it is equally
clear that some of these particles simply remain and accumulate.
“Microplastics are commonly defined
as plastic particles smaller than 5 millimeters and classified into five
general categories: foam; ‘spheres or pellets,’ such as microbeads; jagged ‘fragments’
from larger plastic debris; ‘film,’ such as broken-down plastic bags and wraps;
and ‘fibers,’ from the likes of textiles, fishing gear and even cigarette
filters. Rubber is also considered plastic, both natural (isoprene) and
synthetic (styrene butadiene)…
“Once plastic enters the environment,
it breaks down into smaller and smaller pieces but never goes away. The tiny
particles make their way into the ocean and the stomachs of marine animals, and
ultimately the food and water that people consume.
“A recent UC Davis study sampled
seafood sold at markets in Half Moon Bay, Calif., and found that one-quarter of
the fish and one-third of the shellfish contained plastic debris. A survey
comparing 150 tap-water samples from five continents found synthetic
microfibers in almost every sample — 94% in the United States.
“Microplastics have been found in
Lake Tahoe, in the deep, deep ocean — even in the Arctic, one of the most
remote regions in the world. A scientific review of 52 studies recently
concluded that humans on average consume a credit card’s worth of microplastic
each week. The European Union is trying to classify microplastics as a
contaminant that is unsafe at any level of discharge.” Los Angeles Times,
October 3rd.
Scientists have noted some additional risks
generated by this form of plastics pollution: “While plastic products entering
the ocean represent a range of varied polymers and plasticizers, many absorb
(taking in) and adsorb (sticking to) other persistent organic pollutants and
metals lost to the environment, resulting in a long list of toxicants
associated with plastic debris. Gas stations will sometimes use giant mesh
socks full of polyethylene pellets draped around storm drains to absorb
hazardous chemicals before they reach the
watershed. In the aquatic environment, plastic behaves similarly, mopping up
chemicals in surrounding water. Several persistent organic pollutants (POPs)
bind to plastic as it is transported through the watershed, buried in sediment,
or floating in the ocean. A single pellet may attract up to one million times
the concentration of some pollutants in ambient seawater, and these chemicals
may be available to marine life upon ingestion.
“The chemistry of plastic in consumer products
raises human health as well as ecological concerns. For
example, they include polyfluorinated compounds (‘PFCs’) and the
pesticide/sanitizer triclosan, also used in over-the-counter drugs,
antimicrobial hand soaps and some toothpaste brands, flame retardants,
particularly PBDEs [polybrominated
diphenyl ethers, often used as such flame retardants], and nonylphenols.
Bisphenol A (BPA), the building block of polycarbonates, and phthalates – the
plastic additive that turns hardened PVC into pliable vinyl − are both known
endocrine disruptors.” From Microplastics: What Are the Solutions? by ,
and
Driving is not just an air pollution
and climate change problem — turns out, it just might be the largest
contributor of microplastics in California coastal waters.
“That is one of many new findings,
released Wednesday [9/2], from the most comprehensive study to date on
microplastics in California. Rainfall washes more than 7 trillion pieces of
microplastics, much of it tire particles left behind on streets, into San
Francisco Bay each year — an amount 300 times greater than what comes from
microfibers washing off polyester clothes, microbeads from beauty products and
the many other plastics washing down our sinks, sewers and storm drains.” LA
Times.
The solutions are wildly expensive
and difficult to measure… but they are necessary as the European Union
considers regulations to regulate this outflow as “hazardous materials.” Except
at the state and local level in the U.S., it clear that the potential of
federal intervention and regulation under the Trump administration is nil. Time
is not on our side, and nature does not care if we self-destruct. How do we
even approach a solution?
“Doing no more harm requires upstream
intervention. The further upstream mitigation occurs, the greater the
opportunity to collect more plastic with less degradation and fragmentation and
identifying sources before environmental impacts occur. For most scientists and
policymakers, ocean cleanup is not economically or logistically feasible,
moving the debate to upstream efforts, like zero waste strategies, improving
waste recovery, and management and mitigating point and nonpoint sources of
microplastic creation and loss to the environment…
“There is wide agreement that
microplastic at sea is a case of the tragedy of the commons, whereby its
abundance in international waters and untraceability makes it nearly impossible
to source to the company or country of origin. In terrestrial environments,
identification to source is easier due to less degradation, but capturing and
quantifying microplastics in any environment is difficult and can easily be
contaminated or misidentified, and in inland waterways there is the challenge
of sorting debris from large amounts of biomass. In the United States provisions under the Clean
Water Act and state TMDLs (Total Max Daily Loads) direct environmental agencies
to regulate plastic waste in waterways, like California’s TMDLs, though they
are often limited to >5 mm and miss microplastic entirely.” Microplastics: What Are the Solutions? Too difficult to deal with? How bad do health
and environmental problems from such pollutants have to get before we care
enough to deal with this?
I’m
Peter Dekom, but at a minimum, we can live a little bit smaller, think about
what we are throwing away and what we are discharging down the drain… and care.
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Want another ray of hope, assuming the enzymes, bacteria and fungi themselves do not create new environmental problems? Try this: “Three years ago, Japanese scientists discovered a tiny new bacteria with an unusual ability: The organism, which lived in soil near a plastic bottle recycling plant, could eat plastic. A year later, a plastic-eating fungus was discovered in a landfill in Pakistan. The year after that, a college student discovered plastic-eating bacteria in a polluted site in Houston. Now, researchers from Hitachi and Cambridge Consultants, an engineering and product development company, plan to use synthetic biology to manufacture a similar plastic-eating enzyme. It could later be used in recycling plants or in the environment—and potentially even in the ocean, where as much as 12.7 million metric tons of plastic ends up every year.” Adele Peters writing for the October 3rd FastCompany.com
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