Asbestos
Asbestos has never been a major concern in water treatment. Asbestos is actually a general term used to describe six separate fibrous materials. All have separable long fibers that are strong and flexible. Asbestos forms the basis of more than 3,000 separate products. For example, brake pads, roofing and cement pipe for water distribution. It has been a popular product since the 1800s because of its strength and resistance to heat. It is very absorbent and has great tensile strength. Asbestos exists in natural sources, but the main exposure to humans is from the breakdown of manufactured products. Use of asbestos cement for water pipes has been the main contributor of asbestos to water supplies. Long exposure to asbestos can cause lung disease and cancer, but there is no known health effect from short-term exposure. The most common exposure is breathing air in workplaces where asbestos products are made. Long term exposure through breathing leads to a disease called asbestosis—development of scar-like tissue in the lungs and the membrane that surrounds the lung. EPA MCL for asbestos in water is 7,000,000 fibers per liter. [This is not an ideal figure, but EPA concedes that it is difficult for water suppliers to remove asbestos below that level with present technology.] OSHA also has regulations for asbestos fibers in the air at workplaces. What are asbestos' health effects as regards drinking water?
In 1989 the EPA issued an Asbestos Ban and Phase Out Rule, but this rule was subsequently overturned. Currently, trace amounts of asbestos are allowed in consumer products. Treatment for Asbestos in Water: “The following treatments have been approved by the EPA for removing asbestos from water: Coagulation/filtration, direct and diatomite filtration, and corrosion control.” (Water Technology magazine, July, 2010.) To our knowledge, there are currently no asbestos treatment methods recommend for point of use. |
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