Pesticides from farms in Southern Brazil can end up in rivers during floods. The study looked at how pesticides move with water and sediment in the Conceição River watershed. They found pesticides like simazine and glyphosate in the water, and AMPA in the sediment. The way pesticides move depends on how much it rains, when pesticides are used, and how much sediment is carried by the water. Using a lot of pesticides, heavy rain, and not controlling runoff can make the problem worse. Monitoring pesticides during big rain events is important to see how much ends up in the environment.