Plastic pollution ‘poses hidden and persistent threat’ to food supply — study

Microplastic could have a serious impact on food production by reducing ’ ability to perform photosynthesis, experts have warned. The chemical process is used by certain organisms to convert carbon dioxide and water into oxygen using energy from the Sun.

Researchers in analysed data from 157 previous studies to investigate the impact of plastic pollution. They found that exposure to microplastics appeared to reduce the photosynthesis of terrestrial plants, marine algae, and freshwater algae by 7% to 12%. It also appeared to decrease the total chlorophyll (a pigment involved in photosynthesis) content of such organisms.

Writing in the journal PNAS, the team from Nanjing University and the Chinese Academy of Sciences concluded that the effects of microplastics could “pose a hidden yet persistent threat to global food security, highlighting the urgency of integrating plastic mitigation into global efforts to ensure a sustainable food supply”.

They estimated that such photosynthesis losses could lead to a 4% to 14% reduction in the annual global production of rice, wheat, and maize.

The experts wrote: “In 2022, between 691 and 783 million individuals were affected by hunger as a consequence of conflicts, climate extremes, economic shocks, and growing inequality.

“Microplastics exposure is expected to exacerbate this crisis, with a net increase of hundreds of millions of people estimated to be at risk of starvation worldwide.”

British researchers cautioned that the work was speculative and may have overestimated the impact of microplastics on food supplies.

Professor Denis Murphy, an expert in biotechnology at the University of South , said it was important to note that there are hundreds of different forms of microplastics which differ in their chemical composition, size and environmental distribution.

Cautioning against a “one size fits all” approach, he added: “While this analysis is valuable and timely in reminding us of the potential dangers of microplastic pollution and the urgency of addressing the issue, some of the major headline figures require more research before they can be accepted as robust predictions that, for example, might affect policy on food production.”

Dr Florian Busch, a plant physiologist at the University of Birmingham, said: “While photosynthesis is the driver behind biomass production (and thus yield), the relation between the two is not absolute. 

“A given crop plant might grow somewhat slower under conditions that decrease photosynthesis, but the final plant biomass and yield may remain unchanged, only delayed.”