Impact of Well Water Regulations on the Understanding of Lead Occurrence in North Carolina

Presenter: Linnea Wilson

Research Category: Interdisciplinary Topics, Centers and Institutes
College: Bouve College of Health Sciences
Major(s): Health Science
Graduation Date: 2022

In North Carolina, drinking water from private wells is unregulated. The USEPA does not regulate private wells and the North Carolina Department of Health and Human Services (NCDHHS) only tests newly constructed private wells. Moreover, well water samples analyzed by NCDHHS are collected after extensive flushing of the system and only measures levels >5 µg/L. In 2019, our team collected 1,148 first draw and flushed water samples from private wells to assess lead concentrations and provide commentary on current state water safety guidelines. Of first draw samples, 8.3% exceeded the USEPA action level of 15 µg/L. After flushing the systems, only 2.1% of our samples and 2.4% DHHS flushed samples exceeded 15 µg/L. These results demonstrate that lead concentrations are underestimated after system flushing. Additionally, 93.5% of our flushed samples were 1-5 µg/L which would be Ònon-detectableÓ when sampled by the DHHS. Consistent with prior work, we observed that lead was associated with low pH, dug/bored wells compared to drilled wells, and brass corrosion. This underreporting of lead in private well water is a serious public health concern. When consumed lead can enter the bloodstream, with higher water lead levels generally leading to higher blood lead levels. Currently, I am modeling blood lead levels using our and NCDHHS data to explore underestimated lead levels by the state could impact health. Preliminary results suggest sampling procedure and detection limit greatly influence water lead levels measured, likely impacting remediation efforts and may be affecting blood lead levels.