Tuesday, May 11, 2021

‘Potentially dangerous’ levels of microplastics found in rice: researchers

<i>Note that word "potentially".  A near synonym would be "unproven".  And even the chief researcher says: "I don’t think people should be concerned".

Note that most plastics are inert so any toxic level would be high</i>

A world first study has found rice contains a ‘potentially dangerous’ contaminating item, with levels highest in instant rice.

One of Australia’s most popular staple foods has been found to harbour “potentially dangerous” microplastics, a world-first Australian study has found.

University of Queensland researchers at the Queensland Alliance for Environmental Health Sciences identified 3-4mg of plastic in an average 100g single serve of uncooked rice.

The study, published today in the Journal of Hazardous Materials, also found instant or pre-cooked rice contained four times more plastic – averaging 13mg per 100g serve.

Lead author Dr Jake O’Brien said they found washing rice before cooking reduced plastics contamination by 20 to 40 per cent.

Dr O’Brien said they used everyday rice bought from a local store for the research. An average grain of rice was 8mm long, with microplastics defined as a plastic material measuring 5mm or less.

The researchers tested for seven different plastic types ranging from the most common plastic, Polyethylene to plastics used in clothing and food production, laminates, technical engineering, polystyrene, acrylics and tube piping.

The innovative method developed and used by the UQ research team is based on the plastic quantification technique used in their previous studies on plastics in seafood species and sewage sludge.

Dr O’Brien said the presence of microplastics was relatively low, but there was still much to be learned about their effects on human health.

“I don’t think people should be concerned, I think people should be aware,” he said.

“Currently there are many unknowns about how harmful consuming microplastics is to human health, but we do know exposure can cause an element of risk.”

He said it was still very early days in research to develop methods to measure plastic contamination in foods, and it was “really challenging to determine our exposure and exposure sources of these chemicals.”

“We hope this study encourages further research on where plastic contamination of rice is occurring, so we can reduce contamination and increase community awareness of where plastic exposure happens on a daily basis,” he said.

“In future studies, we aim to incorporate a measure of the plastic size, along with the concentration, because potential health impacts from microplastics are likely size dependent.”

Dr Thava Palanisami, a senior research fellow at The University of Newcastle, has been researching microplastics for many years.

In 2019 he co-led a project that combined data from more than 50 studies on the ingestion of microplastics by people.

The project led to a report that suggested people were consuming about 2000 tiny pieces of plastic every week. This was on average 5g – the size of a credit card.

Dr Palanisami said the presence of that quantity of microplastics in rice was a concern.

“Generally the smaller the size, the more potentially dangerous it can be to health,” he said. “It can get into the blood stream and the organs.”

Dr O’Brien said the research, while still in its very early days, showed washing rice before use was the best way to reduce risk. He said future research would examine other staple foods, including grains.