According to the World Health Organization, contaminated water is the largest health problem in the world. Throughout the world, 50,000 human beings die every day to waterborne disease. The Center for Disease Control estimates that 1,000,000 people in the United States of America suffer health problems caused by microbiologically contaminated water each year. In the U.S., an average 1,000 people die every year from water-related diseases. Furthermore, waterborne gastrointestinal infections account for 80% of all diseases in the world. Health-related problems from chemical contamination is also a serious problem. Biological and chemical water-related health problems are expected to dramatically increase around the world as public water treatment centers seem likely to be temporarily disabled by Y2K technology failures. The three natural biological water-related health threats are bacteria, viruses, and protozoa-- all of which are generally invisible to the unaided human eye. Bacteria are one-celled organisms that generally vary from 0.2 and 1.5 microns (maximum 10 microns). The most common waterborne bacteria which cause infections include: typhoid, para-typhoid, dysentery, colibacillosis, and cholera. Viruses vary in size from 0.1 to 0.004 microns. While most a virus can pass through the smallest filter, viruses tend to adhere to particles in the water. Many filters can filter out these virus-carrying particles. Common water-borne viral infections include hepatitis, yellow fever, and poliomyelitis. Protozoa are one-celled animals; they vary in size from 10 to 100 microns. They can be carried by insects or in the form of cysts when outside of the human or animal organism. Water-borne protozoans that cause disease include amoeba, giardia, cryptosporidium, and malaria. Chemicals (found in tap or well water) that may cause health-related problems include toxic chemicals, heavy metals, and common radionuclides. Among the toxic chemicals are trialomethanes, PCB, PCE, detergents, and pesticides. Some heavy metals to be concerned about may include aluminum, asbestos, cadmium, chromium, copper, lead, and mercury. A common radionuclide such as Radon 222 may be found in some well water in areas where Radon is a problem.

-- (Ladylogic@.........), February 17, 2000