Researchers have chased the source of cacao’s cadmium contamination for years. An array of distinct sampling methods and sites led to mixed results. University of Illinois scientists consider the soil factors influencing cadmium’s ride into cacao beans. They aimed feasible and cost-effective ways farmers can minimize uptake.
Scientists re-analysed thousands of data points reported in dozens of published studies. Studies of cacao cropping systems around the world. The study has been published in PLOS ONE.
Acidic pH values also contributed to bioaccumulation of cadmium in leaves and beans.
Scientists understood the routes of cadmium into the bean is the first step to mitigating its uptake. There is more reason than ever to keep cadmium levels low.
Recent EU regulations cap cadmium at 0.1 to 0.8 milligrams per kilogram. It depends on the cocoa product. The standard is forcing many companies to limit imports from cacao-producing regions in the global south. There soils are naturally high in the heavy metal.
Cadmium in cocoa products is a legitimate health concern. Chocolate is a leading source of dietary cadmium in non-smokers. The regulation is bad news for 8 million smallholder farmers for whom cacao is an important cash crop.
Liming soils brings down the acidity. It makes cadmium less soluble and less likely to be taken up by plants. Liming isn’t necessarily simple or affordable for Amazonian farmers. The product isn’t likely available at the corner store. Lime is relatively inexpensive in the U.S. It’s not cheap in high-poverty contexts.
But lime generally increases yield for cacao. It could have dual benefits. Liming could be worth the effort and cost.
The study offers no silver bullet for impoverished growers. But it provides a map for future research. Though researcher plans not to stop indulging in chocolate. Despite the dangers of cadmium.
