Plastic and plastic pollution have been receiving a lot of attention in the media of late. But, as we explore alternative materials, how do we know what their long-term ecological impacts will be? Becky LeAnstey asks this question in our latest ‘On the horizon’ post. 

A world without plastic is difficult to imagine, despite it having only been around for just over a century. Cheap manufacturing costs combined with a durable lightweight material has meant plastic has become ubiquitous in today’s society. The use of plastic has driven new inventions, improved medical treatments and ultimately led to many benefits for people all over the world. Durability however, is also one of plastic’s downsides. If plastic waste is poorly managed it escapes into surrounding environments and can become a persistent pollutant.

Plastic pollution is a worldwide problem that has been receiving more and more attention from both public and governments. While surface-based plastic waste in the ocean is the most visible indication of the problem, what is underneath the water can be just as concerning. Although the breakdown of plastics is slow, many eventually fragment into microscopic pieces called microplastics. These microplastics can bind with other pollutants in water, potentially making them more hazardous. Microplastics are present in both marine and freshwater and are often not fully removed during waste water treatment processes. Studies have shown evidence of microplastic ingestion by river-based macro invertebrates. Some new research has suggested that microplastic contamination is not limited to land and water, and could also be an air pollutant. This greater awareness is driving research into improving recycling and reuse as well as finding alternatives to plastic.

Designers and developers are becoming more aware of rising consumer demand for sustainability and are striving to identify and create new materials and products that can be marketed to this growing sector. Novel alternatives that are still at the experimental stage, such as using cellulose fibres to produce a material similar to polystyrene, could eventually result in significant changes to markets.

However, many of these novel alternatives are still in their infancy, which means there is limited life cycle assessment data, making comparisons of sustainability very difficult. What impact the materials will have on the environment, current waste streams and treatment is also unclear at this early stage.

More established alternatives include bioplastics such as polylactide, based on renewable plant biomass such as maize and switchgrass. Although the feedstock is renewable, unlike traditional plastic, there will be trade-offs in terms of the land and water needed to continually produce these. In addition to this, the temperature needed to biodegrade polylactide means it is unlikely to biodegrade in the average household compost heap. Consequently, this does not help with the problem of plastic waste persistence.

How and where plastic is produced may also change, and monitoring and treatment approaches will have to adapt to this. The rise of open source and 3D printers means products manufactured from plastic can already be created in the home. Rapid uptake of this kind of technology could significantly increase the pathways of exposure to the environment. The ability to produce your own products, incorporating multiple materials into a single item could also complicate recycling at the end-of-life stage. Furthermore, research suggests some of the emissions and associated waste products from the 3D printing process could be harmful to health.

The environmental pathways of the spread and breakdown of plastic in the environment are only slowly starting to be revealed and will need to be better understood if we are to use and treat plastic in the most sustainable way. There are no easy answers and a lot of uncertainty which is why ‘Ecological effects of options for reducing plastic pollution’ was selected as a topic for inclusion in the latest Horizon Scan of Emerging Issues for Global Conservation in 2019. In some cases, and at this point in time, plastic may be the best option for particular products. We need to be clear that we have properly thought through any alternatives to plastic, to ensure they are not inadvertently causing more problems than they solve.

A Horizon Scan of Emerging Issues for Global Conservation in 2019 is available to read in Trends in Ecology and Evolution.

Read more from our ‘On the horizon’ series here:

Introduction  by Bill Sutherland and Nancy Ockendon

Climate change and the capacity of Antarctic benthos to store carbon by Nathalie Pettorelli

Deforestation expansion of plantations and infrastructure threaten Indo-Malay island species by Nafeesa Esmail and Alice Hughes

Options for cultivating rice as climate changes and salinity increases by Erica Fleishman

Mercury rising by Colleen Seymour