Characterizing Waterborne Lead in Private Water Systems
Lead is a common additive in plumbing components despite its known adverse health effects. Recent research has attributed cases of elevated blood lead levels in children and even fetal death with the consumption of drinking water containing high levels of lead. Although the federal Environmental Protection Agency (USEPA) strives to minimize lead exposure from water utilities through the Lead and Copper Rule (LCR), an estimated 47 million U.S. residents reliant on private unregulated water systems (generally individual and rural) are not protected. Detection, evaluation, and mitigation of lead in private systems is challenging due to lack of monitoring data, appropriate sampling protocols, and entities to fund research.
Through a statewide sampling survey, over 2,000 homeowners submitted water samples for analysis. This survey documented that 19% of households had lead concentrations in the first draw sample (i.e., 250 mL sample collected after 6+ hours of stagnation) above the EPA action level of 15, with concentrations as high as 24,740. Due to the high incidence observed, this research focused on identifying system and household characteristics that increased a homeowner's susceptibility of lead in water. However, 1% of households had elevated lead concentrations after flushing for five minutes, which highlighted potential sources of lead release beyond the faucet. Therefore, a follow-up study was conducted to investigate sources and locations of lead release throughout the entire plumbing network. Using profiling techniques (i.e., sequential and time series sampling), three patterns of waterborne lead release were identified: no elevated lead or lead elevated in the first draw of water only (Type I), erratic spikes of particulate lead mobilized from plumbing during periods of water use (Type II), and sustained detectable lead concentrations (>1 ) even with extensive flushing (Type III). Lastly, emphasis was given to understand potential lead leaching from NSF Standard 61 Section 9 certified lead-free plumbing components as the synthetic test water is not representative of water quality observed in private water systems. Overall, this dissertation research provides insight into a population that is outside the jurisdiction of many federal agencies.