Pesticide risks need more research and regulation
- Developing countries lack pesticide regulations, training and knowledge
- Huge gaps exist between laboratory data from the North and realities on the ground in the South
- Experts recommend improving the international body that maintains safety checks
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Developing countries need stronger pesticide regulation and a better understanding of how pesticides behave in tropical climates, according to experts behind a series of articles published in Science today.
They also need an international body to carry out regular pesticide safety assessments — ensuring they are used properly by farmers who are given thorough training in their use — and to monitor the safety of chemical levels in food, the experts say.
In the face of projections that the global population will reach nine billion by 2050, scientists must develop new technologies to make pesticides safer, and continue research into crops that will not require pesticides at all, according to the special section in Science.
Millions of tonnes of pesticides are used each year in agriculture, sometimes with poor oversight and knowledge regarding their environmental impact, particularly in developing countries.
A review article by a team led by Kathrin Fenner, a senior scientist at the Eawag aquatic research institute in Switzerland, looks at pesticide degradation. It also identifies knowledge gaps in what happens to pesticides once they are applied in the field.
According to Fenner, the biggest challenge is relating what is measured in laboratory studies to what is observed long-term in the environment. One example is what happens to pesticides that have been in the soil for a long time and what products they leave behind as they degrade.
"There are situations that are not covered, or not fully covered, by laboratory studies, especially situations in low concentrations in groundwater," Fenner says.
Furthermore, laboratory studies carried out for pesticide regulation in the United States or Europe look at factors specific to those regions, such as climate and soil type, and not at the warmer climate zones where many developing countries lie.
"How relevant that really is to more tropical settings, where you have more organic, carbon-rich soils and higher temperatures, is also somewhat of a knowledge gap," says Fenner.
“If you reduce plant diseases, you could feed 20 to 30 per cent more calories to people.”
Efforts to lower dependency on pesticides altogether is one option addressed in the Science articles.
A review article by Jeffery Dangl, a biology professor at the University of North Carolina, United States, and his colleagues, reveals developments in the understanding of plant immune systems and DNA sequencing that allow scientists to engineer crops that are less susceptible to pests and disease, and thus require less pesticides.
The technology could help tackle environmental concerns, such as groundwater contamination. It could also help reduce plant diseases and recover crop losses.
"We lose 20 to 30 per cent of our global food supply to pests and pathogens every year," Dangl tells SciDev.Net. "If you reduce plant diseases and recover that, you could feed 20 to 30 per cent more calories to people."
The research would have a significant impact on developing countries, where, Dangl says, there are health issues and poor regulation of pesticide use.
"One often sees farmers throwing chemicals on their plants, using their hands, and without proper clothing, and they often use fungicides and pesticides that are no longer allowed in the developed world," he says. "There's poor regulation and poor administration of the regulation."
One solution could be to strengthen the international body that works to maintain regular safety assessments of pesticides.
According to an article by Philippe Verger, from WHO and Alan Boobis, from Imperial College London, this would be done through improved cooperation with the Joint FAO/WHO Meeting on Pesticide Residues, an expert body that aims to harmonise the requirements and risk assessments on pesticide residues.
"We know developing countries don't have the resources to adequately assess the risk of these various chemicals," says Verger. "So the WHO, together with FAO, is providing this regulation to give a framework for evaluating these compounds."
The importance of improving such a body would not be limited to the developing world. It would ensure internationally that pesticides are licensed and used properly, and that farmers have instructions and training for their use. Most importantly, it would monitor the safety of the levels of chemicals in the food we eat.
"If we want to continue to feed the world population, we have to increase productivity. To do that, pesticides will increase globally, so the sector needs to integrate the protection of public health," says Verger.
Science doi: 10.1126/science.1236281 (2013)
Science doi: 10.1126/science.1236011 (2013)
Science doi: 10.1126/science.1241572 (2013)