cadmium in chocolate


The International Atomic Energy Agency (IAEA) published an article on tackling cadmium levels in Cocoa this week.

The organisation is working with farmers in Panama who were severely affected by changes in the EU regulation to restrict imports of foods with cadmium levels higher than 0.8 mg per Kilogram in 2019.

There was widespread concern in the industry about how this would affect farmers, especially in Some Central and South American countries, including Venezuela and Panama. 

For an explanation of what Cadmium is and the risks associated with it, see below, What is Cadmium, and What is the Effect of Cadmium on the body.

Now in an unexpected move from an organisation we do not normally associate with farming, the IAEA might come to the rescue with a scientific approach that can track the progress of Cadmium in the trees and the fruit and help reduce the absorption.

In Panama, in the province of Bocas del Toro, about 1,400 farmers working to traditional cocoa-growing methods face hurdles to get their Cocoa accepted for export because they are grown in a region with naturally high levels of Cadmium in the soil.

The IAEA believed they could find a way to detect how the metal moved from the soil through the tree and into the fruit and apply some science even to control the levels of absorption where it was required.

Working with the Agricultural Research Institute of Panama (IDIAP) and the Food and Agriculture Organization of the United Nations (FAO), the scientists started by measuring the Cadmium in the soil, then the Cadmium in the fruit, and could then determine the levels of absorption.

Atomic Tracing

In an inspired solution, and perhaps why this involved the IAEA, is how they trace the movement and thus the absorption of the heavy metal. 

All elements have isotopes, that is to say, a kind of variant of themselves. Using a car analogy, you can have two identical cars, but one is red, and one is yellow. It’s not a perfect analogy because some isotopes have different properties that can determine if they are stable, or unstable and radioactive. For example, Cadmium has several isotopes, both stable and unstable. 

By introducing into the soil a different and stable isotope of Cadmium than the naturally occurring one found in the soil at Bocas del Toro, they effectively created a tracer element. Sticking with our analogy, if all the cars were yellow and a red car was introduced, it would be easy to follow its path.

Reducing the absorption

Once this was understood, they could then deploy some organic material which increased the PH in the soil. This reduces the absorption of Cadmium by the trees, in effect locking some of the Cadmium in the soil.

Because some variants of Cocoa are less prone to Cadmium absorption, the IAEA has started training locals in using the tracing method to evaluate which of the varieties is most resistant and deploying the anti-absorption techniques.

The hope is that by adopting this strategy, the country’s farmers can get back on their feet and return with confidence to the export market and earn a stable income. 

What is Cadmium?

Cadmium is a silver-coloured metal that most of us might know from being one of the ingredients in some types of rechargeable batteries (nickel-cadmium Ni-Cd). It is found in soil but has a particularly high density in some regions.

What is the effect of Cadmium on the body?

It has a severe effect on kidney health by reducing the ability of the kidneys to act as a filter and increasing the chances of Cancer. Because the metal stays in the body between 10 to 30 years before it is finally absorbed, even small doses of Cadmium can build up in the body and cause these damaging effects.

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