Association between children’s blood lead levels, lead service lines, and water disinfection, Washington, DC, 1998–2006

Evaluate the effect of changes in the water disinfection process, and presence of lead service lines (LSLs), on children’s blood lead levels (BLLs) in Washington, DC. Three cross-sectional analyses examined the relationship of LSL and changes in water disinfectant with BLLs in children 3 times as likely to have BLLs ≥10 μg/dL versus children who never had LSLs. LSLs were a risk factor for elevated BLLs even when WASA met the EPA water action level. Changes in water disinfection can enhance the effect of LSLs and increase lead exposure. Partially replacing LSLs may not decrease the risk of elevated BLLs associated with LSL exposure. ► In Washington, DC, between November 2000 and December 2006, children living in homes with an LSL were at increased risk of having higher BLLs than children living in homes without an LSL. ► This association was strongest during 2003 when chloramine alone was used for water disinfection. ► The association persisted after controlling for the age of housing. ► Partial replacement of LSLs did not result in a decrease in the association between LSL and elevated BLL.