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In 1991, the U.S. Environmental Protection Agency (USEPA) promulgated the Lead and Copper Rule, which established a copper actionlevel of 1.3 mg/L in a 1-liter, first-draw sample collected from the consumer's tap (FederalRegister, 1991a, 1991b, 1992). The rule was established due to potential health concerns causedby elevated copper levels in drinking water. Excessive corrosion of copper can lead to elevatedcopper levels at the consumer's tap, and in some cases, copper corrosion can also lead to pinholeleaks and pipe failure. Water chemistry has a large impact on the type of copper corrosionsolubility that takes place. Phosphate-based chemicals (ortho-, poly-, and blended-phosphates)have been used to control lead solubility and iron precipitation in many drinking water systems.The usefulness of orthophosphate to reduce copper release has also been recognized. Therelationships between the type of orthophosphate, chemical dosage, water quality and coppersolubility are not well defined, nor are the mechanism(s) by which the phosphates work. Somework has shown that polyphosphates can increase metal levels such as lead in water (Holm sub4/sub), sodium chloride (Clsup-/sup), free chlorine (Clsub2/sub Free), hydrochloric acid, sodiumhexametaphosphate (SHMP), and sodium phosphate (Nasub3/subPOsub4/sub) were added to the designatedreservoir to meet desired experimental conditions. Includes 7 references, table, figures.

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Edition: Vol. - No. Published: 11/01/2008 Number of Pages: 6File Size: 1 file , 1.5 MB