The La Palma volcano did not significantly contaminate the island's bananas.

Bananas from La Palma were not significantly contaminated after the Tajogaite volcano eruption in 2021. This is the conclusion of a study conducted using mass spectrometry and published in the scientific journal PLOS One this Monday. Given the possible risk of contamination by ash and magma, a team of researchers from Spanish centers analyzed the composition of bananas in the eruption area in the months following the event. The study confirms that their consumption is safe and healthy.

For most potentially toxic elements, the estimated maximum intake remained below 1% of the tolerable daily intake and in no case exceeded 3%. The study is important not only for the snapshot it shows, but because it reflects how contaminants from a volcanic eruption can pass up the food chain.

In 2021, the eruption of the La Palma volcano caused the loss of 53,000 tons of bananas, equivalent to 50% of its production, which is crucial to the local economy. Volcanoes are one of the main natural sources of heavy metal pollution. Volcanic ash contains heavy metals such as mercury, arsenic, lead, cadmium, and chromium.

"These elements fall into the soil and water, and can then pass into food," explains Luis Alberto Henríquez Hernández , professor at the Toxicology Unit of the University of Las Palmas de Gran Canaria and co-author of the study. "But how many of these elements are discarded and how many are incorporated into the food chain? That's what we wanted to establish in this study."

To do so, they took samples from different locations on the island to compare those closest to the volcano with those farther away. They also analyzed bananas from other islands as a reference for untouched fruit. Both the peel and the fruit were analyzed using mass spectrometry (ICP-MS) to quantify up to 55 inorganic elements. The result was clear: for most potentially toxic elements, the estimated maximum intake remained below 1% of the tolerable daily intake and in no case exceeded 3%.

“Banana consumption habits were taken into account,” Henríquez points out. “That's why the model was designed for the average consumer and the extreme consumer, anyone who consumes a lot of bananas. In both cases, banana consumption poses no risk.”

Pablo Gago Ferrero , a senior scientist at IDAEA-CSIC, highlights the variety of samples analyzed. "It's especially interesting that it includes elements that have been little studied in volcanic contexts, such as rare earths, and that it compares both the before and after of the eruption and different geographical areas," the expert, who was not involved in the study, told the scientific website SMC España . On the same website, Miguel Motas, professor of Toxicology at the University of Murcia, added that "it's quite a novel study" and emphasized that "although the levels of elements increase after the eruption, the toxic risk from these elements is minimal and they don't pose any problems for the population, making bananas not only a safe but also a healthy option."

Henríquez is satisfied with his study, but emphasizes the importance of continuing to analyze the area's plantains to see how they evolve. It seems clear that their consumption was safe from the outset, but their evolution must be monitored, not so much for consumer interest but for scientific reasons. "The introduction of these types of elements into the food chain takes time; it depends on more or less rainfall, the type of soil, the food studied... These transfers vary depending on the link in the food chain we are analyzing, which is why it's important to keep these studies alive and continue monitoring."