Microplastics can poison our health and living environment — here’s how to reduce our exposure to them

About 10 billion tons of plastic have been produced to date, of which around six billion tons have been discarded as waste. This is a severe threat to the environment, particularly oceans and lakes.

When plastics break down into particles smaller than five millimetres we call them microplastics. They are especially worrying.

Microplastics are an emerging threat to human health. They have been detected in organs in the human body and circulating in our bloodstreams. Studies have shown microplastics may deform red blood cells, inhibiting their ability to transport and transfer oxygen.

A study on mice exposed to microplastics found them in every tissue examined, and showed behavioural changes and heightened inflammation. While the exact effects on human health are not yet known, the risk is high enough that we should be very cautious about allowing them to pervade our atmosphere and food supply.

Microplastics have even been detected in high amounts in clouds, where they may affect rainfall patterns. They can also enter our food supply through rainfall.

A recent study of sediments in the Vaal River found an alarmingly high abundance of microplastics, which may enter the local food supply through crop irrigation. The sampling in this study was done in the region of the Vaal River Barrage, which is downstream of the Vaal Dam and fed by rivers that pass through heavily populated areas including Johannesburg.

Sampling at the Barrage gives direct insight into the rates at which we are producing microplastics in major population centres. And sampling at the Vaal Dam, which is the major drinking water supply for Gauteng, provides insight into the extent to which our drinking water is affected. Both these sampling points are needed as we track the levels of microplastics. Those levels are likely to rise dramatically; the microplastics we are seeing currently are only the tip of the iceberg, as there is a lag between the production of plastic, and it breaking down into microplastics.

Read more in Daily Maverick: With microplastics now being found in human blood, nurdle pollution must be tackled

Microplastic proliferation is not tied directly to accumulation of waste plastic. Examination of microplastics to ascertain their source is not an exact science, but it is reported that the main sources of microplastic pollution, at least for now, are car tyres and textiles and the pollution arises, not at the end-of-life when these are discarded as waste, but during their day-to-day use.

In other words, even if we solve the problem of waste plastic, we would still face the problem of microplastics that are emitted during the normal lifespan of products made of plastic.

Avoiding microplastic spread