More than half of the world’s agricultural land at risk of pesticide poisoning

A new study, covering 168 countries, has revealed that 64 per cent of agricultural land worldwide is at risk of pesticide poisoning – with almost a third of these areas considered to be at high risk.

The research, conducted at the University of Sydney and published in Nature Geoscience, modelled the pollution risk of 92 chemicals commonly used in agricultural pesticides and evaluated the risk of those chemicals to soil, the atmosphere and surface and ground water.

The model reveals that Asia has the largest land areas at risk from pesticide pollution, with China, Japan, Malaysia and the Philippines at highest risk of all. As of 2020, about 59.51 per cent of the world’s population lived in Asia, with the result that some of these countries have been labelled ‘food bowl’ nations, home to land that feeds a significant proportion of the world’s population.

Pesticides are a complicated issue. They help ensure bountiful harvests by keeping insect-transmitted diseases at bay, in turn helping to keep food affordable and reducing waste. Nevertheless, the environmental repercussions can be very serious for countless ecosystems. Overuse of pesticides on agricultural land can destabilise ecosystems. Chemicals are also transported to both surface water and ground water through runoff and infiltration, degrading the quality of water sources that humans, animals and plants rely on.

Associate Professor Federico Maggi, Dr Fiona Tang, University of Sydney

‘Our study has revealed 64 per cent of the world’s arable land is at risk of pesticide pollution,’ said Fiona Tang, lead author of the study and a research associate at the University of Sydney. ‘This is important because the wider scientific literature has found that pesticide pollution can have adverse impacts on human health and the environment. Globally, our work shows that 34 per cent of the high risk areas are in high biodiversity regions, 19 per cent in low and lower-middle income nations, and 5 per cent in water scarce areas.’

Agricultural land in Oceania had the lowest pesticide pollution risk, but despite this the region could still be badly affected. ‘Australia’s Murray-Darling basin is considered a high-concern region both due to its water scarcity issues, and its high biodiversity,’ said co-author Federico Maggi. The team also identified watersheds in South Africa, China, India and Argentina as high-concern regions because they have high pesticide pollution risk, bear high biodiversity and suffer from water scarcity.

Associate Professor Federico Maggi, Dr Fiona Tang, University of Sydney

With the global population expected to reach 8.5 billion by 2030, pesticide use is likely to increase in order to meet global food demand. In addition, a warmer climate is predicted to lead to a rise in pest invasions, further exacerbating the problem. Given the repercussions however, the researchers think that pesticide use needs to be tackled.

Dr. Tang said: ‘Although protecting food production is essential for human development, reducing pesticide pollution is equivalently crucial to protect the biodiversity that maintains soil health and functions, contributing towards food security.’

The authors of the study concluded: ‘We recommend a global strategy to transition towards a sustainable, global agricultural model that reduces food wastage while reducing the use of pesticides.’