Caution urged over impact of microplastics



Scientists at Heriot-Watt University have voiced caution over the impact of microplastics on marine life until further research is carried out.
Professor Ted Henry and Dr Ana I. Catarino from the Centre for Marine Biodiversity and Biotechnology acknowledge the need to combat the growing problem of plastics in our oceans and rivers but added unsupported speculation over their effect on the environment could lead to a misdirection of resources.

There are important gaps in our understanding about plastics.

Dr Ana I. Catarino

It is well documented that plastic particles are readily transported throughout the oceans and ingested by organisms. However, the polymers that make up plastics are of minimal toxicity to marine life and may not hold any negative consequences.
Professor Ted Henry said: “The big question is, what harm do these plastic particles pose to marine life? 
“A few studies have shown microplastics being absorbed by marine life in extremely small amounts, but others have found the opposite. At this time, we don't even know whether very small nanoplastics with diameters of less than 1,000 nanometres can be absorbed. 
“The studies that do exists on nanoplastics suggest that such absorption is minimal. 
“In short, the jury is still out.”
The issue of microplastics continues to attract worldwide headlines with key questions remaining around the risk posed to human health as well as on sea creatures.
But in one experiment, the scientists discovered food left in the open was far more likely to be contaminated by plastic particles transported by dust in the air than compared with the numbers found in mussels collected around the Scottish coast. 
Their results revealed that while a UK consumer might ingest 100 plastic particles a year from eating mussels, their average exposure to plastic particles during meals from household dust is well over 10,000 per year.
Dr Ana I. Catarino, a NERC Research Associate at the Institute of Life and Earth Sciences at Heriot-Watt University, says not enough evidence currently exists to know the true impact of these plastics on marine eco-systems. 
She added: “There are important gaps in our understanding about plastics. It's not unreasonable for people to fill these with speculation to some extent – funding for research is limited and we cannot wait for scientific research to provide complete answers before taking action. 
“However, we must avoid undue speculation and overstating risks, and instead engage with the actual evidence. Otherwise it will detract from our ability to manage plastic pollution in the most effective way and have a clear sense of the right priorities.”
Throughout 2018, Heriot-Watt University is celebrating its Year of the Sea with a series of events that will span schools, the public, academia, industry collaborators, funders and policy makers. 
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