One type of nutrients pollution is sewage pollution. It causes disease to form in the water, it has a high level of bacteria which also takes up oxygen in the water, and it releases mineral ions which leads to too many nutrients in the water. When there are too many nutrients, it increases plant life and stops light from coming into the water. It leads to smaller plants dying and fish not having food. In 2009, Rio had huge amounts of nutrients pollution. Many fresh water sources were heavily polluted with sewage and bacteria from pipes, hospitals, and dumps. It was causing harm to humans, plants, and animals around the areas. To help clean it up, wastewater treatment plants and sewage collection systems were built.