The water in your body is billions of years old. It has been recycled millions of times. Not all pollution is manmade. Volcanic ash, for example, can kill aquatic life. Some sediment pollution is caused by natural erosion, without which there would be no Grand Canyon.
Man can do little to control natural pollution.
According to the Federal Water Quality Administration, the United States southeastern region, which includes Virginia, has the lowest percentage of polluted stream miles. By the year 2020, the United States will produce three times the sewage it did in 1970. Cholera, typhoid fever and dysentery are transmitted through water. Chlorination eliminates these diseases. All have been found in ground water and municipal drinking water supplies.