Contaminant Level Goal (MCLG)
Lead is a toxic metal that was regularly used in a wide range of household and industrial products throughout much of the last century, and found in plumbing and service lines until the EPA established a lead ban in 1986.
Lead rarely occurs naturally in water. When found, it is usually a result of industrial, smelting or mining wastes, or from corrosion of plumbing.
Lead is toxic to all humans, but the risk of lead poisoning is highest in children and pregnant women. Children absorb 30-75%, adults only 11 percent.
The EPA lists several symptoms associated with acute lead poisoning:
Lead can cause a variety of adverse health effects when people are exposed to it at levels above the action level [15 parts per billion] for relatively short periods of time. These effects may include interference with red blood cell chemistry, delays in normal physical and mental development in babies and young children, slight deficits in the attention span, hearing, and learning abilities of children, and slight increases in the blood pressure of some adults.
The agency also warns that lead is a potential carcinogen, and can lead to kidney disease or stroke with long term exposure.
Lead can be treated with ion exchange (water softeners) or reverse osmosis. It can also be treated by removing the source, or through corrosion control methods in pipes, including: pH and alkalinity adjustment; calcium adjustment; silica or phosphate-based corrosion inhibition.
Sources: EPA, Water Technology Magazine Volume 31, Issue 8 - August 2008. Photo: images-of-elements.com
(whole house & well units)