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The "Lead and Copper Rule", or LCR, is a United States federal regulation which limits the concentration of lead and copper allowed in public drinking water at the consumer's tap, as well limiting the permissible amount of pipe corrosion occurring due to the water itself. The U.S. Environmental Protection Agency (EPA) first issued the rule in 1991 pursuant to the Safe Drinking Water Act. EPA promulgated the regulations following studies that concluded that copper and lead have an adverse effect on individuals.〔Regina L. Mcgill, "The Influence of an Educational Fact Sheet on Small System Water Supplier Attitudes toward the Lead and Copper Rule," ''Journal of Environmental Health'' 56.4 (1993).〕 The LCR sought to therefore limit the levels of these metals in water through improving water treatment centers, determining copper and lead levels for customers who use lead plumbing parts, and eliminating the water source as a source of lead and copper. If the lead and copper levels exceed the "action levels", water suppliers are required to educate their consumers on how to reduce exposure to lead. A 2004-2005 study of the LCR by EPA noted that the system had been effective in 96 percent of systems serving at least 3,300 people.〔Vipin Bhardwaj, "Question & Answer: Lead and Copper Rule Revisions," ''Journal of Environmental Health'' 68.5 (2005): 46.〕 EPA has stated that the LCR has reduced exposure to lead "that can cause damage to brain, red blood cells, and kidneys, especially for young children and pregnant women." It also explained that the rule has reduced copper exposure "that can cause stomach and intestinal distress, liver or kidney damage, and complications of Wilson’s disease in genetically predisposed people."〔U.S. Environmental Protection Agency (EPA), Washington, DC (2004). ("Lead and Copper Rule: A Quick Reference Guide." ) Document no. EPA-816-F-04-009.〕 ==Background== Although lead is a known poison, the mechanical and chemical characteristics of the metal continue to keep lead as an important component in many products. In water supply, lead's durability and workability selected it for use as water pipes. Lead alloys (bronze, brass) are used for plumbing fittings. Lead solders were preferred in plumbing. While lead pipes were replaced by other materials, such as plastics, early in the twentieth century, lead alloys continued to be used.〔http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2509614/ Lead Water Pipes〕 Although new lead pipes weren't installed later in the 20th century, some existing lead pipes remain in service in many cities. The U.S. Public Health Service published a non-enforceable standard for lead in 1925, consisting of a tolerance limit of 0.1 mg/L.〔U.S. Public Health Service, Washington, DC (1925). "Report of the Advisory Committee on Official Water Standards." Public Health Rept. 40:693. April 10, 1925.〕 Partially because of lead pipes, some states regulated the corrosivity of water put into the distribution system. Waters which would deposit a protective coating on the pipes rather than dissolving the pipe were preferred. Corrosion indexes such as pH or Langelier Saturation Index are not necessarily representative of the lead corrosion potential in a particular water/pipe system, nor did they measure the amount of lead to which customers were exposed. In the second half of the twentieth century, concern was growing about what constituted a safe level of lead. The 1986 Safe Drinking Water Act amendments defined "lead-free" plumbing and prohibited the use of plumbing for public water supply that did not meet the new definition.〔Safe Drinking Water Act Amendments of 1986. "Prohibition on use of lead pipes, solder, and flux." . , approved 1986-06-19.〕 The amendments also required EPA to set standards limiting the concentration of lead in public water systems. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lead and copper rule」の詳細全文を読む スポンサード リンク
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