An assessment of lead exposure potential from residential cutoff valves. (Practical Stuff!).This department, "Practical Stuff!" originated from you, our readers, via your responses on "Tell Us What You Think" forms. Many of you have expressed to us that one of the main reasons you read the Journal of Environmental Health is to glean glean v. gleaned, glean·ing, gleans v.intr. To gather grain left behind by reapers. v.tr. 1. To gather (grain) left behind by reapers. 2. practical and useful information for your everyday work-related activities. In response to your feedback, we dedicate ded·i·cate tr.v. ded·i·cat·ed, ded·i·cat·ing, ded·i·cates 1. To set apart for a deity or for religious purposes; consecrate. 2. this section to you with salient points to remember about two features in each issue. * 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 drinking water supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. 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 United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. 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 corrosive /cor·ro·sive/ (kor-o´siv) producing gradual destruction, as of a metal by electrochemical reaction or of the tissues by the action of a strong acid or alkali; an agent that so acts. , the leaching leaching, method of extraction in which a solvent is passed through a mixture to remove some desired substance from it. A simple example is the passage of boiling water through ground coffee to dissolve and carry out the chemicals necessary for producing the beverage. 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 submersible, small, mobile undersea research vessel capable of functioning in the ocean depths. Development of a great variety of submersibles during the later 1950s and 1960s came about as a result of improved technology and in response to a demonstrated need for 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 ball valve n. A valve regulated by the position of a free-floating ball that moves in response to fluid or mechanical pressure. . * 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. |
|
||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion