A RANGE of food crops which are struggling to cope with extreme weather are generating chemical compounds that can cause health problems for people and livestock who eat them, scientists have warned.
Crops such as wheat and maize are creating more potential toxins as a reaction to protect themselves from extreme weather, a new report by the United Nations Environment Programme (UNEP) said.
But these compounds are harmful to people and animals if consumed for a prolonged period of time, according to the report.
“Crops are responding to drought conditions and increases in temperature just like humans do when faced with a stressful situation,” explained Jacqueline McGlade, chief scientist and director of the Division of Early Warning and Assessment at UNEP.
Under normal conditions, for instance, plants convert nitrates they absorb into nutritious amino acids and proteins. But prolonged drought slows or prevents this conversion, leading to more potentially problematic nitrate accumulating in the plant, the report said.
If people eat too much nitrate in their diets, it can interfere with the ability of red blood cells to transport oxygen in the body, it added.
Crops susceptible to accumulating too much nitrate in times of stress include maize, wheat, barley, soybeans, millet and sorghum.
Some drought-stressed crops, when then exposed to sudden large amounts of rain that lead to rapid growth, in turn accumulate hydrogen cyanide, more commonly known as prussic acid, the report said.
Prussic acid – one of the ingredients used in some types of chemical warfare – interferes with oxygen flow in humans, McGlade said.
Plants such as cassava, flax, maize and sorghum are most vulnerable to dangerous prussic acid accumulation, the report said.
Aflatoxins, molds that can affect plant crops and raise the risk of liver damage, cancer and blindness, as well as stunting foetuses and infants, also are spreading to more areas as a result of shifting weather patterns, scientists said.
McGlade said about 4.5 billion people in developing countries are exposed to aflatoxins each year, and the numbers are rising.
The report said Europe will be at growing risk from aflatoxins in locally grown crops if global temperatures rise by at least 2ºC. The world is on a path to a more than 3ºC temperature rise, scientists believe.
