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Hong Kong environmental issues

Your toothpaste may be irreparably damaging Hong Kong’s marine life – all because of tiny plastic beads

Hong Kong researchers find exfoliating microbeads commonly seen in beauty and personal care products can be devastating to even the toughest of species, which sometimes end up on our plates

PUBLISHED : Monday, 05 March, 2018, 11:00pm
UPDATED : Tuesday, 03 July, 2018, 5:31pm

Microbeads – the tiny plastic pellets added to many beauty and personal care products for their “exfoliation effect” – can cause irreversible damage to even the toughest of marine species if exposure comes in high enough concentrations, Hong Kong researchers have found.

The study sheds further light on the complicated environmental impact of microplastic pollution in the world’s oceans, which by some estimates contain up to 50 trillion such particles.

Found in products ranging from facial scrubs to toothpastes, microbeads, which are manufactured microplastics, are small enough to be washed down drains and flushed into the ocean, where they can end up in the digestive tracts of fish and other marine creatures that humans eat.

In two separate experiments each lasting two years, researchers at the University of Science and Technology’s division of life sciences exposed two common, pollution-tolerant marine invertebrates to concentrations of microbeads.

Both suffered irremediable impairments to their growth and development.

In one test, slipper limpets that were exposed to high concentrations of pollutants – more than 1,000 beads per millilitre of water – in their diet at their larval stage only grew to about 70 per cent of their normal size.

The tiny sea snails are an invasive species in Hong Kong and have a reputation for being hardy and resilient.

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They are generally unaffected by normal environmental concentrations of microplastics in the sea, according to Professor Karen Chan Kit-yu, who led the study.

Results from another test group, which was exposed to a microbead-infested environment for two weeks and then switched back to a normal diet for three months, found the stunted growth rate could not be reversed.

“This shows a strong legacy effect of the exposure,” Chan said. “Even if the pollutants are removed from their environment, they are still negatively affected.”

In another test, bristle worms – harvested commercially as fish bait – were exposed to microbead-infused water. They were unable to regenerate their tails as quickly as those placed in cleaner water. Small beads caused more damage than larger ones.

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“Small beads are more likely to be confused as food, and the speed at which toxins are released is quicker,” Chan said.

The studies were recently published in the scientific journals Environmental Pollution and Marine Pollution Bulletin. Sea urchins are their next test subjects.

Chan said it was the first time scientists had shown that the harmful effects of microplastic pollution were not confined to upscale, commonly consumed invertebrates such as abalones and oysters.

Previous studies have indicated that high microplastic exposure in invertebrates such as mussels could cause the pollutants to enter the digestive system. It can also induce liver toxicity and pathology in other vertebrates and fish.

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In Hong Kong, 9.3 billion microbeads are released into local waters every day. Chan urged Hongkongers to avoid using microbead-containing products.

“Do something before it is too late,” she said.

A Baptist University survey commissioned by Greenpeace in 2016 showed there was a lack of public awareness about the matter in Hong Kong. About 85 per cent of 804 adults polled did not know certain products contained plastic microbeads. Two-thirds did not know they could pollute the sea.