Fluoride in River Water: What's Happening in Argentina's Mountains?

In Argentina's Sierras de Ambato, rivers flowing through granite mountains carry high levels of fluoride. This fluoride comes from the breakdown of minerals in the rocks and sediments. The main culprits are micas, which are minerals rich in fluoride. When these micas weather, they release fluoride into the water. Scientists studied the Rincón River to understand this process better. They used special techniques like XPS and leaching experiments. These methods helped them see how fluoride moves from the rocks into the water. They found that fluoride can stick to other minerals for a while, but it eventually gets released, especially when the water flow is low.The amount of fluoride in the river changes with the seasons. It's higher during the dry season because there's less water to dilute it. This means that people who rely on these rivers for drinking water might be at risk. High levels of fluoride can be harmful if consumed over a long time. The study shows that the type of rock in the area plays a big role in how much fluoride ends up in the water. This is important for other places with similar granite rocks. It highlights the need to monitor and manage water resources carefully to protect the health of local communities.