Microplastics – There are two categories for those tiny pieces of plastic less than 5mm across: primary and secondary. A good example of primary microplastics is microbeads from the cosmetic industry. Secondary microplastics are broken-off bits of larger pieces, such as fibres from synthetic clothing and tyre abrasion.
Plastic has very poor degradability and is a major source of pollution in the sea. The sea floor is the final resting place for everything including plastics and the figure for this has tripled since the year 2000.
Data of plastic litter on the seafloor from the Global Oceanographic Data Centre found, more than a third of the total amount of human debris was plastic and of that, 89% was of single-use items.
Microplastic makes its way into the food chain when fish and shellfish ingest it. Studies found that 49% of fish have microplastic in them with around 3.5 pieces per fish. North America had the highest rate of microplastics in fish compared to any other region.
While a portion of these ingested microplastic passes through the digestive system of fish and is expelled, some migrates to other parts including, the fillet and liver where it may remain.
Is there more microplastics in some seafood than others?
According to research from the University of Hull, shellfish including mussels, oysters and clams had more microplastic in them than fish, with up to 10.5 microplastics per gram. This compared with 8.6 microplastics per gram in crustaceans and 2.9 in fish.
While the University of Ghent in Belgium found that those who eat shellfish in the EU consume 11,000 microplastics yearly.
Countries with the most plastic pollution are USA, India, China and suprisingly, Maldives. Flinders University found high concentrations on the beaches which they attributed to ocean currents as well as poor waste management practices there.
What are the human health impacts?
Microplastics can enter the body through inhalation or ingestion.
Ingestion can be from eating food that contains them such as fruit, vegetables, fish and shellfish.
Microplastic also leach into food and water from plastic packaging. Bottled water, in fact, introduces more microplastics into our bodies than anything else! The full effects of microplastics inside the human body are as yet unknown but there is evidence that they can damage cell membranes and affect functioning.
Although we don’t know the harmful effects on humans, we do know that microplastics affect the endocrine system in birds and reproductive system in fish, as well as stressing the liver.
Smaller studies on humans have found microplastics in the lungs, blood and even the placenta of unborn babies. While we don’t know the implications of this, we do know that microplastics have toxins in them and they should not be in our bodies.
What can we do?
We may not be able to control microplastics entering our bodies, but we can reduce our usage of single-use plastics. Especially, bottled water. Using a reusable bottle is a simple solution.
As more of us express our distaste for single-use plastics, more pressure is put on the government and merchants to change. We saw this with the banning of plastic straws, cotton buds and the charge on carrier bags.
Recently, it was announced the UK government are introducing a ban on single-use plastics such as disposable cutlery, food containers, and balloon sticks in England in October.
If we all make a small effort to reduce our single-use plastics by 20% this year this will bring a positive change. The less plastic there is entering the environment, the less enters our bodies.