Beyond Water Regulation: Contamination of Private Wells, Citizen Science, and Corrosion of Household Plumbing

The US Safe Drinking Water Act (SDWA), established in 1974, has improved water quality nationwide through the introduction of maximum contaminant levels, source water protection, and treatment guidelines and requirements. Despite the obvious success many important water quality issues are not covered by regulation. These include the following four topics in this dissertation: 1) Support infrastructure for private well users, 2) Identification and analysis of contaminants in private wells, 3) Leaks or corrosion within building plumbing, and 4) The role of citizen scientists in addressing water quality concerns. Private wells, which provide water for approximately 13% of the population (42.5 million people), are not subject to any federal regulation and well users are responsible for ensuring their own water safety. When water quality issues do arise, state or local organizations can provide critically important support. For instance, in North Carolina (NC) local health departments (LHDs) are required to have private well programs that enforce statewide well construction standards, offer water testing services, and provide well water outreach and assistance. Little is known about the effectiveness of such programs, however, so this work conducted a survey of all NC LHDs to determine their capacity for well water outreach and identify differences among programs around the state. All LHDs reported overseeing the construction of new wells as required by law. However, services provided to existing well users were offered infrequently and/or inconsistently offered. Lack of uniformity was observed in the number of LHD staff and their assigned responsibilities; the costs and availability of well water testing; and the comfort of LHD staff communicating with well owners. While the total number of staff was lower in LHDs in rural counties, the number of outreach activities and services offered was typically not related to the number of well users served. Variations in structure and capacity of well programs at LHDs has created unequal access to services and information for well users in NC. Such gaps in NC, which has among the most stringent state guidelines for well water support, suggests the need to examine conditions in other states nationwide. While direct support to private well users is more common at the state and local levels, the scientific information and resources needed by these officials can be supplemented at the federal level or through academia, especially with respect to emerging contaminants, which many officials may not yet have experience with. For instance, following Hurricane Florence in 2018, dam failures and flooding of coal ash disposal and reuse sites in NC prompted concerns about potential contamination of well water with hexavalent chromium. There is also widespread naturally occurring Cr(VI) in the groundwater however, and methods accessible to state and local officials to identify sources are needed. Literature was reviewed related to source tracking techniques and they were applied to Cr(VI) data we collected from 1,265 private wells across 22 NC counties. Almost two thirds of private wells tested (62.0%) exceeded the Cr(VI) public health goal of 0.07 ppb, with concentrations ranging from <0.02-13.9 ppb (median=0.12 ppb). In the literature review, we identified 33 Cr(VI) groundwater tracking techniques from 51 publications and only 5 techniques were used in more than 12 papers. All papers used different combinations of techniques. We applied these techniques to our well sampling data, and inconclusive results were reported for 7 techniques, while three techniques suggested potential geogenic sources whereas three techniques indicated anthropogenic Cr(VI) sources. Specifically looking at coal ash, two techniques did not support coal ash as a primary source and three were inconclusive. Overall, these techniques did not agree as to the origins of Cr(VI) in well water. This may be due to the fact that these techniques primarily focused on regional scale identification, rather than household-level occurrence. This study demonstrates the difficulty and complexity in identifying and distinguishing the source(s) responsible for Cr(VI) in well water. In addition to private wells, another gap in the SDWA framework involves corrosion of plumbing within a home or private building. The Lead and Copper Rule (LCR) was the first SDWA legislation to include sampling at the tap in private buildings, although these results are only used to inform control of the corrosivity of the water at the treatment plant. Thus, there is no maximum level of lead or copper enforced at the consumers tap, and protection against excessive private plumbing corrosion is not required. A survey conducted about a decade ago suggested that recent efforts to increase temperatures of hot water systems to better control Legionella bacteria might also be increasing pinhole leaks in copper plumbing. Recently, an overseas large building experienced at least 300 pinhole leaks in a hot water recirculation system that frequently exceeded > 65°C in 2018. The occurrence of leaks along the top of the pipes where thick deposited of metal oxides were not visibly protective, was not consistent with conventional patterns of failure, but seemed to be a manifestation of an unusual type of hot water pitting due to the presence of cathodic iron or manganese oxide suggested in prior literature. A macro-cell apparatus was developed and tested to mechanistically test this novel hot water pitting corrosion mechanism experimentally. Cathodic manganese oxides deposits were shown to drive pitting corrosion on a part of the pipe surface without deposits. Pitting occurred over a wide range of pH and was worst at a high ratio of sulfate to bicarbonate. While iron oxide coatings tested in this work did not behave cathodically, as suggested in prior literature, further research could determine if some iron oxides might behave similarly to the manganese oxide tested in this work. Past failures to follow provisions of the SDWA has undermined trust in water safety nationally. Collaborations between citizens and scientists can sometimes expose problems with water safety. Over the last decade we have helped consumers evaluated their concerns using citizen science collaborative approaches. We documented and summarized several case studies conducted by the U.S. Water Study team at Virginia Tech that had varying degrees of success in exposing problems with water supplies via citizen science collaborations. The case studies start with a discussion of work in Flint, MI (lead and Legionella bacteria) in 2015 and St. Joseph, LA in 2016 (lead and iron). Later cases included: Enterprise, LA (lead and iron), Denmark, SC (lead, iron, and Halosan), Chicago, IL (lead), Moore, OK (arsenic), Santa Barbara, CA (copper), anonymous town in SC (Acanthamoeba), and Harrisonburg, VA (Legionella). Approaches, challenges and outcomes of each case study are reviewed along with lessons learned.

Overall, this dissertation explored water quality issues which, for various reasons, fall outside of the existing SDWA regulatory framework. The importance of well water support was emphasized by documenting inequalities between local health departments well services and by critically reviewing literature to find a lack of scientific guidance for source determination for an important emerging contaminant. Development of a novel apparatus for monitoring of chemistry related hot water pitting allows for a better understanding of this mechanism and provides a baseline of guidance for avoiding or mitigating such problems in the future. Finally, the use of citizen science to address past water quality concerns and that considers reasonable expectations for future work was evaluated.