Plastic is everywhere. It is in cars, in computers, in water bottles – and increasingly also in the ocean and in our drinking water. In this article we aim to answer why more and more plastic waste ends up in landfill sites or the ocean, how this plastic finds its way back to us as microplastic particles, and whether it poses a health risk.

Nowadays, many people have gotten used to take-away food and, consequently, to the plastic containers it is delivered in – be it in the form of PET bottles, cling film or plastic bags. The use of such containers is just one example that illustrates how abundantly plastic items are used in our society. However, while single-use plastic packaging may be convenient for consumers and economically viable for producers, it also generates an enormous amount of waste.

In 2018, the US alone produced 32 million metric tons of plastic waste, of which only 9% were recycled; the rest was either incinerated (16%) or put into landfill sites (75%) [1]. This distribution of plastic waste treatment is representative of most countries on the planet [2] and highlights a key issue: plastics are not easily recyclable. This is in part because there are numerous different types of plastic with various applications, and in order to have a chance to recycle one particular type, it has to be pure. For example, a PET recycling process can be ruined when contaminated by only a small amount of PVC [3]. Moreover, for most common plastics used in packaging, such as PVC, recycling is much more expensive than new production. Also, even plastics that are generally thought to be recyclable, like PET, are most often ‘downcycled’ to lower grade materials, such as fleece, which cannot be recycled anymore. Therefore, the commonly chosen options for plastic disposal are incineration – which is controversial due to the release of harmful substances into the atmosphere – or landfill – which requires physical space that is becoming increasingly sparse [3].

As a consequence, a drastically increasing amount of plastic waste ends up in the oceans [4] where sea currents accumulate it into massive patches of floating plastic waste. The most popular example of such a patch is the ‘Great Pacific Garbage Patch’ located north of Hawaii [5]. Such accumulations of plastic waste obviously pose a significant threat to marine wildlife [6]. Moreover, the constant movement of seawater breaks down macroscopic plastic waste – such as pieces of packaging – into tiny microplastic particles that can enter the bloodstream and organs of fish and other sea animals [7].

Such microplastic particles have also been discovered in drinking water [8] and even in human tissue [7]. Scientists are currently investigating the effects of these particles on human health with some studies pointing towards an inflammatory response upon exposure [9]. Yet, many experts find that sufficient knowledge about the effects of microplastics on humans is lacking and they are therefore hesitant to draw conclusions [10].

However, it is becoming very clear that the way plastic waste is handled globally is not sustainable. Therefore, significant efforts are being made to solve this problem. One solution could be infinitely recyclable plastic – a material engineered to be fully and effectively recycled time and time again [11]. Another solution could be the use of special man-made enzymes that rapidly degrade plastics, like PET, into their precursor components so that new plastics can be made from them [12]. Such approaches may seem like science fiction, but many of them have already been shown to work effectively.

Yet, the most impactful thing that we consumers can do to battle increasing plastic waste would be to cut down on single-use plastic items – even if this means ordering less take-out.