Phosphates stimulate the growth of plankton and water plants that provide food for fish. This may increase the fish population and improve the waterway’s quality of life. If too much phosphate is present, algae and water weeds grow wildly, choke the waterway, and use up large amounts of oxygen. Many fish and aquatic organisms may die. Phosphorus compounds are used in explosives, nerve agents, friction matches, fireworks, pesticides, toothpastes, and detergents.