Identifying and Responding to Lead in Drinking Water in a University Setting

Overview

This primary study describes a seven-month systematic lead testing campaign at the University of North Carolina at Chapel Hill (UNC-CH) following the discovery of elevated lead in campus drinking water in 2022. The campaign tested 5,954 fixtures across 265 buildings, finding that 8.43% of tests and 11.03% of fixtures had detectable lead above the 1 ppb limit of detection. Fewer than 1.5% of tests exceeded the EPA action level (AL) of 15 ppb. The maximum detected concentration was 1,100 ppb from a 2SS (second sequential sample) at a 1969-era drinking fountain. Buildings constructed before 1975 showed substantially higher lead prevalence. The study provides a remediation and communication framework for higher education institutions, which are not currently subject to federal lead-in-water regulations.

Key numbers

Overall testing summary (n = 5,954 tests):

• Tests above LOD (1 ppb): 502 (8.43%)
• Tests above 10 ppb (NC hazard level / WHO guideline): 83 (1.39%)
• Tests above 15 ppb (EPA action level): 61 (1.02%)
• Tests above 20 ppb (EPA 3Ts threshold): 50 (0.84%)
• Mean concentration (all samples): 1.69 ppb
• Median concentration: 0.71 ppb
• Maximum concentration: 1,100 ppb (2SS from 1969 drinking fountain)

By fixture type:

• Sinks (first draw): highest prevalence, 15.71% above LOD; 2.35% above 10 ppb; max 96.3 ppb
• Drinking fountains (1SS): 7.74% above LOD; 1.30% above 10 ppb; max 515 ppb
• Drinking fountains (2SS): 6.01% above LOD; 1.24% above 10 ppb; max 1,100 ppb
• Bottle fillers (1SS): 2.87% above LOD; 0.21% above 10 ppb; max 16 ppb

By building age:

• Pre-1900: 10.53% of tests above LOD
• 1900-1950: 12.33% above LOD
• 1950-1975: 11.72% above LOD; max 1,100 ppb
• 1975-2000: 9.21% above LOD
• Post-2000: 2.59% above LOD

Regulatory benchmarks applied: AAP 1 ppb, WHO/NC 10 ppb, EPA AL 15 ppb, EPA 3Ts 20 ppb

Method: EPA Method 200.8, ICP-MS (Thermo Scientific iCAP RQ ICP-MS); LOD 1 ppb; samples analyzed at Pace Analytical Services and Eurofins Scientific. Sampling per EPA 3Ts guidance. Cost of campaign: USD 553,377 (not including remediation or staff time).

Methods (brief)

Three-phase systematic testing of all fixtures in all buildings by construction period. Sequential sampling (1SS/2SS) for fountains and bottle fillers after 8-18 hour stagnation; first-draw sampling for sinks. Values below LOD imputed as LOD/sqrt(2). Data analyzed in R v4.2.2. As of April 2024, 98.81% of fixtures with detectable lead had been remediated.

Implications

Certification: This paper is out of scope for food product certification thresholds. Relevant to drinking water as an exposure route for lead; important for institutional food service settings (cafeteria drinking water, formula preparation water in schools or childcare). The finding that 1.02% of tests exceeded 15 ppb in a regulated university environment with a corrosion control program underlines the persistence of legacy infrastructure as an exposure source.

Courses: Strong case study for institutional response to lead discovery: cross-campus network mobilization, systematic vs. selective testing, cost quantification, and transparent communication framework. Useful comparison data: UNC-CH (5,954 samples) vs. comparable institutions (next highest was 1,135 samples), with UNC-CH showing the lowest exceedance rate relative to tests conducted.

App: Not directly applicable to food product contamination estimates. Drinking water Pb is relevant to formula reconstitution risk but requires a separate water-quality data layer.

Wiki pages updated on ingest

• Lead
• lead-exposure-routes

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