NEW global mapping shows that 64 per cent of the agricultural land in 168 countries is at risk of pesticide pollution.
More worrying is that almost a third of the affected land is considered to be at high-risk.
The study, published in Nature Geoscience, produced a global model mapping pollution risk caused by 92 commonly used agricultural pesticides.
The study examined risk to soil, the atmosphere, and surface and ground water.
The map also revealed Asia has the largest land areas at high risk of pollution, with China, Japan, Malaysia, and the Philippines at highest risk. Some of these areas are considered "food bowl" nations, feeding a large portion of the world's population.
University of Sydney research associate and the study's lead author, Dr Fiona Tang, said the widespread use of pesticides in agriculture - while boosting productivity - could have potential implications for the environment, human and animal health.
"Our study has revealed 64pc of the world's arable land is at risk of pesticide pollution," Dr Tang said.
"This is important because the wider scientific literature has found that pesticide pollution can have adverse impacts on human health and the environment."
Pesticides can be transported to surface waters and groundwater through runoff and infiltration, polluting water bodies, thereby reducing the usability of water resources.
"Although the agricultural land in Oceania shows the lowest pesticide pollution risk, 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 Associate Professor Federico Maggi from the School of Civil Engineering and the Sydney Institute of Agriculture.
Some of the mapping is confusing (see map below), suggesting there are potential problems in extensive grazing areas where chemical usage is extremely low. These areas include Cape York, most of western Queensland and large areas of pastoral NSW, South Australia and Western Australia.
Queensland Country Life has asked the authors why the mapping appears to generally follow the Queensland/Northern Territory border, when cattle production dominates both areas.
Also, the mapping does not appear to reflect the development of intensive agriculture in the Northern Territory, in particular horticulture.
"Globally, our work shows that 34pc of the high-risk areas are in high-biodiversity regions, 19pc in low-and lower-middle-income nations and five percent in water-scarce areas," Dr Tang said.
There is concern that overuse of pesticides will tip the balance, destabilise ecosystems and degrade the quality of water sources that humans and animals rely on to survive.
Future outlook
Global pesticide use is expected to increase as the global population heads towards an expected 8.5 billion by 2030.
"In a warmer climate, as the global population grows, the use of pesticides is expected to increase to combat the possible rise in pest invasions and to feed more people," Associate Professor Maggi said.
Dr Tang said although protecting food production was essential for human development, reducing pesticide pollution is equivalently crucial. to protect the biodiversity that maintains soil health and functions, contributing towards food security."
Co-author Professor Alex McBratney, Director of the Sydney Institute of Agriculture at the University of Sydney, said the study showed it was important to carefully monitor residues on an annual basis to detect trends in order to manage and mitigate risks from pesticide use.
The authors of the paper recommended a global strategy to transition towards a sustainable, global agricultural model that reduced food wastage while reducing the use of pesticides.
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