The Long Road to Clean Water: Doce River's Struggle After Mining Disaster

The Doce River in Minas Gerais, Brazil, faced a significant challenge after the Fundão tailings dam burst in 2015. The focus is on whether the river's water quality has recovered since the disaster. To find out, 15 different water quality measures were checked. These measures were compared from before and after the dam collapsed. Nine spots along the river were picked for water samples, with six of these spots being where water is taken for drinking. After the dam broke, there were more problems with certain pollutants in the water. These included iron, aluminum, color, cloudiness, and tiny particles floating around. However, there was a drop in manganese and lead levels. These findings are based on guidelines set by COPAM in 2008. When looking at the data over time, no clear patterns emerged. Only iron, total dissolved solids, and aluminum showed changes in how spread out the data was. This was found using a test called Levene's test. When comparing the middle values of key pollutants before and after the dam collapse, there were no significant changes. This was found using a test called the Mann-Whitney test. For seven specific metals, there were changes in the middle values and sudden shifts in the data after the dam broke. These metals were arsenic, cadmium, chromium, lead, mercury, nickel, and zinc. However, it is hard to say for sure what caused these changes. Some changes were seen in tests and monitoring stations even before the accident. After the accident, it is still not clear if the river is getting better. This shows how important it is to keep checking the water quality in the Doce River. The Doce River is not the only waterway that has faced problems because of mining. Many rivers around the world have been affected by pollution from mining activities. This includes acid mine drainage, which can make water too acidic for plants and animals to live in. It also includes heavy metals, which can build up in the food chain and harm wildlife and people. The Doce River's struggle highlights the need for strong regulations and monitoring to protect our waterways from mining pollution. It is also worth noting that the Doce River is an important waterway for both people and wildlife. It flows through several states in Brazil and provides water for drinking, farming, and industry. It is also home to many different species of plants and animals. The river's health is closely tied to the health of the people and wildlife that depend on it.