Streams, lakes, and oceans can all be polluted, but pollution can have a different effect on each of them. Streams can recover from moderate levels of degradable and oxygen-demanding wastes through dilution and bacterial biodegradation. This operation can take from several days to several weeks. This process is extremely helpful, but it doesn't work when a waterway becomes overloaded with such pollutants or when drought, dams, or water diversion reduce its flow. This process also does not remove slowly degradable and non-degradable pollutants. Lakes and reservoirs are less effective at diluting pollutants. The flow and exchange of water in lakes can take anywhere from one to a hundred years, much longer than that of streams. Groundwater extraction is a very important method of providing drinking water to people. Pollutants such as fertilizers, pesticides, gasoline and organic solvents can enter groundwater. The natural removal process can take decades or thousands of years (Miller, 2014). Oceans can become polluted by pesticides, herbicides, chemical fertilizers, detergents, oil, sewage, plastic and other solids. These pollutants collect in the depths of the ocean where they are consumed by marine organisms. These pollutants can kill or mutate marine life. Humans also end up consuming fish contaminated by pollutants, which can be very harmful (National Geographic, 2016). It is very important to conserve all the bodies of the earth