Plastic: fantastic microjunk

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Rhonda Lee McIsaac —

“Microplastics are everywhere,” Dr. Gies said, as she handed out small bottles full of brightly coloured samples to those gathered at the Haida Heritage Centre this past month.Vancouver Aquarium research biologist Dr. Esther Gies was here to present her latest research on microplastics.

Since the 1950s the production of plastic has increased dramatically. In the 50s we produced about 1.5 tonnes worldwide. Today close to 300 million tonnes of plastic is produced every year and as useful as the substance is, it’s made to last and does not biodegrade significantly, said Gies. If you take a short walk along a beach anywhere on the Islands you can find many items from the 2013 Top 10 Items Found Along Shorelines, including cigarette filters, bottle caps, bottles, cans, straws and plastic or foam packing

At least eight millions tonnes of plastic end up in the ocean every year and much of it accumulates and circulates in five gyres, or patches, spread out across the Earth’s oceans. The Atlantic and Pacific Oceans have two patches, which are governed by the North and South Equatorial currents and there’s also a patch in the Indian Ocean. The North Pacific Ocean patch is 268,581 square miles (695,622 km2), the size of Texas; the microplastic in also the gyres don’t just float around on top, but are also suspended in the water column looking like translucent slurry.

The durability of plastic is what makes the substance so convenient, but that is also part of the problem. It takes a plastic bag 10-20 years to degrade in the ocean and the plastic never does actually go away, it just breaks down into smaller and smaller pieces.

Particles less than five millimeters in size, which have broken or worn off larger pieces of plastic are also a big problem, said Gies. The issue with debris at this microscopic size has recently come to light in the media due to the realization that plastic microbeads being used in personal care products such as exfoliating shower gel, toothpaste, and makeup, all which end up flushing down the drain, into the ocean and then into the food chain.

Secondary microplastics like those that have broken down or worn off larger items like buckets, bottles, and totes also add to the problem, as does discarded packaging.

The small pieces of plastic that break off these larger items are a threat to marine animals, which can get tangled in the debris: things like pop tin packing bands or fishing line and net, which takes 600 years to degrade. Between 2005-2012 there were a reported 550 sea lion entanglements to which the Vancouver Aquarium responded.

Dr. Gies is able to identify specific microjunk using what she calls the “magic plastic machine” but is also known by it’s manufacturing name, the Fourier Transform Infrared Spectroscopy!

“It reads, detects and analyzes microplastics and other materials and then compares it to what is found in a known library [of samples]. It can determine between natural and plastic materials,” explained Gies. “The machine even lists the manufacturer of the plastic type.”

Microfabrics are also abundant but less obvious, Gies said. Microfabric particles are often finer than silk, which is finer than the smallest human hair, but can be readily seen under a microscope.

Vancouver Aquarium researchers found 50 plastic fibres in wild oysters and 178 in farmed mussels.

The problem with crustaceans ingesting microfibres is that it can affect the animal’s growth, reproduction, digestion, and even their survival instincts.

Gies cited the example of European perch larvae, which had ingested polystyrene, the substance that many plastic bags are made of. After it had eaten the plastic the larvae tended to not evade predators and after only 16 hours the larvae was eaten by a predator.

Because these products don’t actually biodegrade, this micro junk is also accumulating in our food chain, Gies explained.

The filter feeder, zooplankton, which is at the bottom of the chain, ingests plastic and fabric 1.3mm to 0.4 mm in size, the plankton is then eaten by a juvenile salmon and although most of us don’t eat the contents of the salmon’s stomach it doesn’t mean that microjunk is not getting into our bodies. It is – we are just ingesting it in other ways. One way is when we launder our fleece clothing and the dryers vent those microparticles into the air we breathe.

“We are just at the beginning of our understanding about microplastics,” Gies acknowledged.

Dr. Esther Gies received her doctorate in Microbial Ecology from the University of British Columbia in November 2015. She is now working as a postdoctoral researcher for the Vancouver Aquarium’s Ocean Pollution Research Program. Her work focuses on microplastic pollution in the ocean, including the transport of microplastics into the ocean.


Categories: Marine


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