Scientists at the IAEA develop and use techniques using radiotracers to better understand how contaminants move through the marine food chain. Radiotracers are chemical elements, either natural or artificial, that have a unique signature, almost like a fingerprint. They can be used to study natural processes like the flow of water, bone growth rate as well as trace the movement of different substances. They can also be used to track contaminants in the marine environment, such as metals like mercury or cadmium; radionuclides, such as caesium and americium; and organic pollutants, such as polychlorinated biphenyls (PCBs) and pesticides.
The scientists have also developed a way to replicate the human digestive process in the laboratory by creating a mix of enzymes. This allows them to observe which contaminants are broken down during digestion and which remain in the system.
Tracking the flow of contaminants is particularly important for keeping people safe, Metian explained, as the contaminant concentration levels can increase the higher up they get in the food chain, potentially putting people at risk. This amplification process is known as biomagnification. This is a process where contaminants enter the environment and are absorbed or eaten up by small organisms, which in turn are eaten by larger organisms. These contaminants then accumulate in the organisms and their concentration increases. Animals like tuna, whales, and even humans face a greater risk of toxins and contaminants building up and posing a health threat.