An assessment of lead exposure potential from residential cutoff valves. (Practical Stuff!).
* Tap water continues to represent 14 to 20 percent of total lead exposure for U.S. residents.
* Until recently, nearly all household kitchen and bathroom faucets were constructed of 2 to 7 percent leaded brass.
* These faucets leach high amounts of lead into residential drinking water when new and, in many cases, even after years of use.
* In 1995, all major U.S. faucet manufacturers agreed to phase out the use of leaded-brass alloys in faucets by the end of 1999.
* Nearly all were in compliance by the end of 1997.
* But virtually all residential brass water meters installed in the United States are made of 5 or 7 percent leaded brass.
* These meters leach significant amounts of lead into drinking water when new.
* If the composition of the water is corrosive, the leaching continues after many years.
* A lawsuit filed in California led to an August 1999 settlement under which the nine major U.S. manufacturers of these meters agreed to switch to lead-free brass alloys by 2001.
* In late 1994, the manufacturers of submersible well pumps, which provide drinking water to over 40 million U.S. residents, switched to lead-free brass alloys.
* Through these regulatory and litigatory initiatives, the exposure of the U.S. public to lead in drinking water has steadily decreased over the past decade, especially for the residents of new buildings.
* Decrease in exposure risk has been much less for residents of older buildings.
* One of the remaining sources of lead in residential drinking water is cutoff valves.
* As of March 2002, the valves used in residential plumbing systems continue to be made with 5 to 7 percent leaded brass.
* This study measured the amount of lead discharged by valves under laboratory conditions.
* It was found that the typical resident would be exposed to small amounts of lead from each valve, particularly from gate and ball valves.
* Typically, water passes through three to six such valves before reaching the tap.
* Thus, leaded-brass valves represent a significant, widespread, and needless source of lead exposure, especially given that numerous models of no-lead valves are now commercially available.
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|Publication:||Journal of Environmental Health|
|Article Type:||Brief Article|
|Date:||Jul 1, 2002|
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