The Safe Drinking Water Act of 1974 requires the EPA to establish national drinking water standards, called maximum contaminant levels. (MCL). By 1990 the EPA had set maximum levels of only 65 of at least 700 potential pollutants. Of the chemicals found in drinking water that have been tested, 97 cause cancers, 82 cause mutations, 28 are toxic, and 23 promote tumors in test animals. By 1995, the EPA is required by Congress to set new standards for 108 drinking water contaminants.
Municipal Water Treatment: Water from a lake, reservoir, river, or wells is pumped to a treatment plant. At the treatment plant, (1) chlorine is added to kill bacteria, (2) alum (aluminum sulfate) is added to coagulate organic particles, (3) the water is put into a settling basin to let the precipitate settle, (4) it is then filtered through sand filters, (5) treated with lime to adjust the pH, and (6) put into a storage reservoir until delivery to homes.
Some people object to using chlorine because it may react to form very small concentrations of some cancer causing compounds. However, if the bacteria are not killed, a person has a greater chance of dying from water borne diseases.
Adapted from: Miller, G., Living in the Environment, 7th Ed., Wadsworth Pub. Co., 1992 p. 629.
In 1990, about 1 in 17 Americans spent more than $2 billion to buy bottled water at an average price 700 times that of tap water. Water bottling companies can legally get their water from springs, wells, or public water from the tap. More than one third of the bottled water sold in the U.S. comes from the same ground water and surface waters that provide municipal tap water. Sellers are not required to identify on their labels the source of the water or the type of purifying equipment, if any, used.
Bottled water is regulated by the FDA, not the EPA, and the FDA requires bottlers to check only 22 of the 30 chemicals tested for in the tap water provided by municipalities. Only bottled water marketed over state lines must meet all federal drinking-water standards, and testing is required every one to four years, except for bacteria, which are tested weekly. Bottlers are not required to submit test results to the EPA as do the municipalities. FDA inspectors check bottling plants only every two or three years. Mineral water is not regulated by the FDA or any other agency.
An important consideration is whether the bottler belongs to the International Bottled Water Association (IBWA) and adheres to the testing requirements. The IBWA requires its members to test for 181 contaminants and sends an inspector from the National Sanitation Foundation, a private lab, to bottling plants annually to check all pertinent records. By 1991, IBWA water testing standards were required in 15 states.
Consult: Consumer Reports, January, 1987 for test evaluation of 50 bottled waters. Consumer Reports, January, 1990 for evaluation of water treatment equipment.
Terms: coagulation, floc, settling tanks, sand filters, chlorination What are the general processes which are used to convert "raw" water into drinking quality water? What tests and their results are done to ensure water quality?
In preparation for the debate, go to the grocery store and make an inventory of some the types of bottled water. List brand names, claims of purity, ingredients lists, methods of purification etc.