Plastic is a fantastic invention that helps make our modern living possible.
Unfortunately, plastic waste has become one of earth’s major contaminants. Every Australian discards an average of 100 kg of plastic waste each year.
We led a study which found agricultural systems and our food supply are increasingly impacted by micro and nanoplastic pollution. The study is one of the first to analyse the academic literature on microplastics from a food safety and food security risk viewpoint. It's clear more research needs to be done.
How are plastics getting into our food supply?
Previous studies have found that plastic travels into waterways and is ingested by the fish we eat. However, we discovered there are more likely pathways for plastic to get into our food.
One major route is contamination from the machinery, equipment and plastic wrapping used to handle, process and package food. Fresh food can start off plastic free but contain plastics by the time it’s been handled, packaged and makes its way to us.
Over 10,000 additives help give plastic its useful properties such as making it flexible or resistant to UV radiation. They include compounds such as flame retardants, heavy metals, phthalates and hardeners among others. However, these chemicals can leach into our environment, also potentially contaminating our food supply. Their concentrations, and thus the potential severity of this issue, remain unquantified.
This study highlights that more research is needed to understand the impact plastics and their additives could have on agricultural systems and our food supply. It’s imperative to improve our understanding of the concentrations of these plastics in the environment and what levels could cause toxicity.
Food security and biosolids fertiliser
The new study also looks at biosolids as a potential source of microplastics on agricultural land.
Did you know that the synthetic materials we make our clothes from, such as polyester, viscose, elastane and others release plastic microfibres when we wash them?
Over 700,000 microfibers are shed from synthetic clothing during an average 6 kg washing machine cycle. Luckily, more than 90 per cent of those synthetic fibres get captured by sludge when the water from our laundries reaches our local wastewater treatment plants.
The treated sludge material is called biosolids, and concentrations of plastic in it vary. Biosolids are considered a rich fertiliser for agricultural land and growing crops. When biosolids are used on soil, plastics may accumulate and change the soil structure. Over time they can affect how well crops grow.
Plastic fibres may also ‘trick’ the good bacteria in the soil into thinking they are the roots of plants. This can mean the plants end up with less of the nutrients they need, which may affect crop production, future food security and ecosystem resilience.
This makes it important to measure microplastic content in soils and agricultural land to ensure correct use of this valuable circular economy fertiliser.
No definite evidence of health effects
There are currently no definitive studies that show micro and nanoplastics in the environment are harmful to humans. More research is needed to better understand any health effects. It is particularly important to get a better understanding of how many particles people are typically exposed to and at which concentrations these become toxic.
More research is also needed to develop better analytical techniques to monitor, assess and establish safe levels in food, drinking water and agroecosystems.
As evidence continues to emerge over time, we can all take steps to reduce plastic pollution and limit human exposure to these particles.
What can you do to help?
There are some simple measures we can all take to help reduce micro and nanoplastic waste from cycling through the environment and entering our food supply.
Avoid plastics where possible in the kitchen for food storage, especially for hot food. Single-use plastics in particular shed a lot of particles in their first use. It’s best not to reheat food in plastic in the microwave, especially in take-away food containers.
You could use non-plastic cutting boards such as wood, bamboo or stone.
When clothes shopping, consider clothes made from natural fibres such as cotton, bamboo, linen or hemp. Wash your favourite clothes a little less often. Opt for full loads, with shorter cycles and cold water. These steps can reduce synthetic microfibres entering our wastewater systems.
Car tyres shed micro and nanoplastics through abrasion when you drive. Another good reason to use public transport where possible or plan ahead to consolidate multiple trips.
And finally, join us on our mission to end plastic waste, with a goal of an 80 per cent reduction in plastic waste entering the Australian environment by 2030.