Strong Association between Children’s Elevated Blood Lead Levels and Lead Service Lines: A Census Tract-Level Analysis for Two Midwest Cities

The contribution of lead service lines (LSLs) to children's blood lead levels (BLLs) has long been suggested but has been difficult to quantify due to limited LSL inventory data. This study examines the association between LSL prevalence and elevated BLLs (EBLLs; ≥5 μg/dL) among children served by the Grand Rapids Water System (GRWS) and the Greater Cincinnati Water Works (GCWW). Address-level LSL records were aggregated to the census tract level and linked with EBLL prevalence data. Strong positive correlations were observed between LSL prevalence and EBLLs in both GCWW (<i>r</i> = 0.71, <i>p</i> < 0.001; <i>n</i> = 195) and GRWS (<i>r</i> = 0.83, <i>p</i> < 0.001; <i>n</i> = 52). Linear and weighted quantile sum (WQS) regression showed that LSL prevalence was a stronger predictor of Pb exposure risk than EPA's Random Forest Models (RFv1 and RFv2) and HUD's Deteriorated Paint Index, though somewhat weaker─but comparable─to Vox's Lead Exposure Risk score. In WQS models including multiple predictors, LSL prevalence received the highest component weight for GCWW and surpassed the threshold of significance for both systems. These findings underscore the independent contribution of LSLs to children's lead exposure and support LSL replacement as an effective public health strategy.