Authors: Dr. Arshad M. Khan and Meena Miriam Yust
The ubiquitous plastic water bottle, crystal clear and shiny, can find its way into lakes, rivers and the oceans, carelessly discarded by cruise ships so notorious for the occasional dumping of garbage into the seas on long cruises; that bottle or parts of it can end up inside marine animals.
If plastic waste gets lodged in their stomachs, the poor creatures have a mistaken feeling of fullness and become nutritionally deprived causing an early death.
Polyethylene Terephthalate (PET) is the plastic used to make the bottles. It is light in weight, clear, has high strength and stiffness and high chemical resistance i.e. barrier properties — being also cheap makes it a desirable choice. But it takes centuries to degrade.
Polycarbonates are used for the harder plastics like baby bottles and refillable ones, also for dinnerware, eyeglass lenses, even compact discs. And they form the protective lining for beverage and food cans. But research on a chemical, bisphenol A (BPA), used in its manufacture is a cause for concern: it disturbs the hormone estrogen, possibly increasing cancer risk.
If BPA is no longer being used in baby bottles and sip cups, it still lines steel cans. The Food and Drug Administration maintains the amounts leaching into the contents do not pose a risk to human health.
More than 380 million tonnes of plastic are produced annually worldwide. The figure represents what is around to pollute our environment if not disposed of safely.
In the U.S., a total of 35.7 million tons of plastics were disposed of in municipal solid waste (MSW) in 2018, according to the American Chemistry Council. Landfills received 27 million tons. Another 5.6 million was combusted together with other MSW recovering energy for heating and power generation. Only 31 million tons were recycled representing less than 9 percent. For PET bottles the number is higher, closer to 29 percent.
Aside from fossil fuels, big oil also produces lentil-sized plastic pellets called nurdles from petroleum. These are bought by manufacturers in large plastic sacks and fed into injection molding machines to make the everyday plastic items we see around us. As can be expected, the nurdles can be spilled — as an example, a container ship carrying them foundered a few years ago spreading them in the sea around the southeastern United States.
Trillions of nurdles are produced each year and sent to factories all over the globe. They are then melted and formed into various products – anything from plastic bottles to electronics to car parts. Unfortunately, not all nurdles are melted into products. Unregulated, 200,000 metric tonnes of nurdles, 10 trillion by number, end up in the oceans annually. Looking remarkably like fish eggs, these can even be swallowed by small fish, filling stomachs and causing starvation.
Plastic bottles have been found inside marine mammals’ stomachs. And smaller pieces can find their way into the stomachs of littler creatures — fish, birds, oysters, to name a few.
Beached whales are often discovered to contain plastics in their stomach, sometimes in quantities large enough to have compromised feeding and digestion. One found in Scotland two years ago had ingested a horrendous 220 pounds of plastic.
Changing consuming habits can help. Plastic straws will take a couple of centuries or more to degrade. Why not straight from the glass or use a paper one. Regular coffee drinkers collecting their morning brew can bring their own favorite mug or an insulated container.
There is one piece of good news: a team of University of Texas scientists have developed a protein enzyme (FAST-PETase) which breaks down PET making it easier for natural decomposition.
In the end, as with most things, it’s up to us …