Plastic Plague in Our Oceans Print
Earth News
Written by Joan Russow
Wednesday, 28 January 2015 08:23

By  Dr Mae-Wan HoISIS Report 28/01/15

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Plastics production has gone up 560-fold in just over 60 years to 280 million
tonnes a year, less than half recycled or buried in landfills, the rest litter
the oceans damaging marine life throughout the food chain; scientists call for
the most toxic plastics to be classified hazardous waste, and ultimately for all
plastics to be reused and recycled in closed-loop systems. Dr Mae-Wan Ho

Most comprehensive global estimate to-date

Over five trillion pieces of waste plastic are floating in our oceans weighing
268 940 tonnes and causing damage throughout the marine food chain, according to
data collected by a team of scientists from the United States, France, Chile,
Australia and New Zealand [1, 2]. The team went on 24 expeditions between 2007
and 2013 that surveyed all five sub-tropical gyres (large rotating ocean
currents): North Pacific, North Atlantic, South Pacific, South Atlantic and
Indian Ocean, and extensive coastal regions and enclosed seas (Bay of Bengal,
Australian coasts and the Mediterranean Sea), and include surface net tows and
visual transects for large plastic debris at 1 571 locations in all oceans.

This is the most comprehensive survey to-date, yet it is most likely a gross
under-estimate of the scale of waste plastic pollution in the oceans.

Waste plastic an escalating environmental hazard

In 2012, 280 tonnes of plastic was produced globally; less than half consigned
to landfill or recycled. Much of the remaining 150 million tonnes not still in
use litters continents and oceans [3]. Global trends suggest that waste plastics
are accumulating exponentially in parallel with trends in plastic production
that has increased 56o fold in just over 60 years. These by-products of the oil
industry are icons of the industrial economy built on the over-exploitation of
oil and other fossil fuels that's turning the planet literally into a terminal
wasteland [4] (Redemption from the Plastics Wasteland, SiS 29).

The estimate from the global survey of plastic pollution on the sea surface for
all fragment size classes combined is only 0.1 % of the world annual production.
The estimates are “highly conservative”, the team acknowledged [2]. They do not
account for the potentially massive amounts of plastic washed up on shorelines,
submerged on the seabed, suspended in the water column, and inside organisms.
Also, the survey only collected particles larger than 0.33 mm, due to the size
of the netting used. Sequestration in the sediment is the likely fate of plastic
pollutants after perpetrating numerous impacts on organisms along the way.

Waste plastic in the open ocean is degraded into smaller and smaller fragments
through UV radiation, mechanical abrasion, biological degradation, and
disintegration. The fragments disperse in the ocean, converging in the
subtropical gyres. Generation and accumulation of plastic pollution also occur
in closed bays, gulfs and seas surrounded by densely populated coastlines and
watersheds. The impacts through ingestion and entanglement of marine organisms
ranging from zooplankton to whales, seabirds and reptiles are well documented,
and new studies are showing up harmful effects of nano-size plastic particles
that have escaped inventories so far (see [5] Plastic Poisons in the Food Chain,
SiS 65).

The data from the global survey showed that during fragmentation plastics are
lost from the sea surface [2]. There is a 100-fold discrepancy between the
expected microplastics (particles < 4.75 mm) weight and abundance and the actual
amounts observed, indicating a tremendous loss of microplastics. This suggests
removal processes are operating, including UV degradation, biodegradation (by
microorganisms), ingestion/absorption by organisms, decreased buoyancy due to
fouling organisms, entrapment in settled detritus, and beaching. Fragmentation
rates of already brittle microplastics may be very high, breaking them down into
ever smaller submicron or nanoparticles, and unrecoverable by the nets. Numerous
studies demonstrate that many more organisms ingest small plastic particles than
previously thought, either directly or indirectly via their prey organisms.
These are then packaged into faecal pellets which sink to the bottom.  Further,
there is evidence that some microbes can degrade microplastics.

Plastics should be classified hazardous waste

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