Assessing lead-contaminated drinking water in a large academic institution: a case study.

Drinking water is an important source of lead exposure, and definitively characterizing the sources of lead in drinking water, particularly in large institutional settings, can be time-consuming and costly. This study examined lead concentrations in drinking water at a large university, focusing on variability in first-draw samples and variability with dispensed volume. Over 350 sources were sampled twice by independent groups, and while 78% of these samples were within 2.5 mu g/L, almost 10% differed by >10 mu g/L. In both sampling events, approximately 50% of sources had lead concentrations >1 mu g/L, 6% were >15 mu g/L, and 30% were between 1 and 15 mu g/L. The highest lead concentration detected was 400 mu g/L, with five sources >100 mu g/L. Nine sources were sampled more intensively and six had first-draw sample ranges >5 mu g/L. Lead concentration versus dispensed volume profiles indicated that while most sources had decreasing lead concentrations after the first draw, others had maximum lead concentrations at higher dispensed volumes. The variability observed suggests that assessments using only one or two samples per source may not identify all sources with elevated lead concentrations, and management strategies should account for this possibility.