Nano Girl Michelle Dickinson: How cosmetic microbeads affect marine food chain

In 1976, chemical engineer John Ugelstad invented a technique on Earth that other scientists believed could only be carried out in the weightless conditions of space.

His discovery enabled the mass production of monodisperse spheres, tiny microscopic spherical plastic beads. The beads were typically 0.5-500 micrometres in diameter, about the width of one to five strands of human hair.

These little beads enabled new advances to be made in cancer treatments and helped create alternative methods for HIV, bacteriology and DNA research.

Tiny latex beads still form the basis for some home pregnancy tests today and thanks to Uglestad's discovery the medical use of microbeads has helped move drug treatments forward.

More recently, microbeads have moved from medical additives to exfoliators found in face washes, toothpaste, body scrubs, and other everyday beauty products.

The non-biodegradable solid plastic beads are commonly made from polyethylene, polypropylene, and polyethyleneterephthalate, the same plastics used for single-use shopping bags and plastic bottles.

After they have been washed off your skin, the microbeads go down the plughole and into the waste-water treatment plant where some of them become trapped in the filtering sludge, but some microbeads pass through into our waterways and oceans.

Because their size and shape is similar to many plankton species, microbeads are eaten by marine creatures such as shrimp and fish caught for human consumption.

Plastic particles from microbeads and other plastic items in the ocean have been found in the stomachs of fish, shellfish, turtles and birds and have caused harm to these creatures.

Plastic microbeads have been found to act like magnets around organic pollutants with reports indicating a single immersed plastic particle can absorb up to one million times more of these chemicals than the water around it. The common pollutants including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides, and perfluorinated surfactants (PFCs) have been found to stick to the beads due to their large surface area and the chemistry of the plastics used.

This absorption transforms the microbeads into chemical-carrying dots, and new research published in the journal Environmental Science and Technology found that when feeding on similar-sized food in the water, fish also ate PBDE-exposed microbeads from a commercial facial scrub.

After just 21 days, 12.5 per cent of PBDE chemicals were found to have leached from the ingested microbeads into the tissues of the fish, causing concern that persistent organic pollutants accumulate in the tissue of fish exposed to microbeads and other plastic debris.

Research is now under way to determine the implications this chemical exposure pathway has on public health by calculating how much pollution could be entering the human food chain.

Many large cosmetics companies have made voluntary commitments to phase out microbeads by 2020 but they are easy to spot in the liquid if consumers want to avoid them. Alternatives include sea salt, apricot kernels and ground seeds which can be used as biodegradable skin exfoliates.

Microbeads, are just one source of our oceans' plastic pollution problem, and many other plastics grind down over time into small plastic pieces causing similar issues.

This year, Canada became the first country in the world to list microbeads as a toxic substance under its Environmental Protection Act, allowing it to ban them in personal care products.

The US has also moved to ban the production of personal care products and cosmetics containing microbeads from July 2017. It's pleasing to see these other nations leading the way with their legislation. Looking at the recent science research, let's hope that New Zealand will follow suit.