The document discusses water pollution and provides details about various types of water pollutants and their sources. It summarizes that water pollution occurs when foreign materials contaminate water supplies, harming living things. The major types of water pollutants are biological impurities like bacteria, inorganic impurities such as heavy metals, and organic impurities including pesticides. Pollution comes from natural sources like volcanic eruptions and human sources such as sewage, industrial waste, and agricultural runoff. Water pollution harms ecosystems, animal health, and human health by causing diseases and environmental damage. Several major rivers around the world are severely polluted due to waste dumping and lack of treatment, including the Mississippi, Ganges, and Yellow Rivers