Globally, freshwater use has tripled since 1950 due to rising populations and increased agricultural irrigation. This causes people to go to ever greater aquifer depths and increase surface collection to get sufficient supplies. Glaciers provide fresh water for much of the world's populations. The Tibetan plateau, for example feeds Asia's river systems bringing water to over 2 billion people. It goes without saying, water is a critical resource.
Drought is also an ongoing concern. When groundwater supplies are depleted they cannot be replenished. Water shortages are anticipated in 36 states by 2013. The causes are not fully understood, but the net reality is that a drier climate will lead to lower supplies. Even today, the Colorado River goes dry for part of the year. As it does, so goes the level of supply in Lake Mead and other important lakes and waterways.
Americans on average use 100 gallons of water per day. Translated: that is 1,600 glasses of water. Water for household use comes either from private wells or municipal systems. Public water systems provide 90% of the drinking water, gathered from either aquifers or groundwater, including rain and snowmelt flowing into rivers, lakes and reservoirs. To protect public health, the EPA regulates water safety. There is good reason to do so. Contaminants routinely cleansed in utility systems fall into five categories: Microorganisms, disinfectants, inorganic chemicals, organic chemicals and radionuclides. Microorganisms include viruses and cryptosporidium from animal waste and can cause gastrointestinal illness. Disinfectants we use to purify the water break down into two categories: Disinfectant byproducts include bromated (cancer risk) and trihalomethanes (liver, kidney, and nervous system problems). Disinfectants include water additives such as chlorine to control microbes (stomach problems). Inorganic chemicals run the gamut from atrazine from herbicides used on crops (cardiovascular problems) to benzene from factories, gas storage tanks and landfills (cancer and anemia). Organic chemicals range from arsenic from glass and electronics production (cancer risk) to cadmium from waste batteries and paints (kidney damage) to nitrates from fertilizer (dangerous to adults and children). Radionuclides include radium 226 and 228 from erosion of natural deposits (cancer risk). One can see why landfills are so heavily monitored and controlled. The EPA website www.epa.gov provides an eye-popping list of every substance that is harmful to our water supply.
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