Full Description

A switch from free chlorine to chloramine disinfectant triggered problems with excessivelead in Washington, D.C., drinking water. High levels of lead originated in the service lines, butexcessive lead was also derived from solder or brass plumbing materials. In many cases,the highest lead concentrations emerged from the tap after about 1 minute of flushing, atroublesome outcome, given that routine public notification recommended that consumers flushfor about a minute to minimize lead exposure. Bench-scale testing found that chlorine reactswith soluble Pb+2 to rapidly precipitate a red-brown-colored lead solid that was insolubleeven at pH 1.9 for 12 weeks; this solid did not form in the presence of chloramine. Furtherexperiments indicated that chloramines sometimes dramatically worsened lead leachingfrom brass relative to free chlorine, whereas new lead pipe was not strongly affected. Includes 51 references, figures.

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Edition: Vol. 96 - No. 10 Published: 10/01/2004 Number of Pages: 13File Size: 1 file , 370 KB