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. / Doctor of Philosophy / In the United States, drinking water is usually collected and treated by a local drinking water treatment plant before being sent out to all customers within a city or community. Since the 1970's, the US Environmental Protection Agency (EPA) has regulated treatment plants to make sure they do not send out water that could be potentially dangerous to the health of those drinking, cooking, or bathing with it. These EPA regulations have helped deliver cleaner and cleaner water across the country, but they do not protect every aspect of drinking water for every person in the US. This dissertation covers four topics that EPA regulations do not cover including: 1) Support systems for people getting their water from private wells, 2) Understanding dangers to safe water in unregulated private wells, 3) Leaks in plumbing within a building, and 4) The role of citizens working closely with scientists to determine if their water is safe.
More than 1 in 10 people in the US get their drinking water from private wells, and EPA regulations do not protect the safety of that water. Instead, consumers are on their own to make sure it is safe to drink. When water that could be dangerous is discovered, state or local governments are important sources where residents can get help in treating it. For instance, in North Carolina (NC), local county health departments are required to have programs focused on private wells. The goals of these programs are to make sure new wells are built according to legal codes, offer to test well water for residents, and answer questions people have about their well water. No one has ever determined how well how well health departments meet these goals. This work sent a survey to each health department in NC to figure out how much each was doing and identify any differences between counties. All health departments were checking new wells to make sure they were installed according to state law. But all health departments did not provide support or answer questions of people who had older wells. Some of the differences were due to the number of staff working on these problems, costs charged for well water testing, and the confidence with which staff answered well water questions. Well users in different NC counties get a different level of service as a result. The fact that these differences exist in NC, a state believed among the best in supporting private well owners, suggests a need for a similar analysis in other states.
Local health departments and state agencies are more likely to work directly with people concerned about their well water. College or federal government researchers can still help support these groups. Extra support is important when contaminants that state or local officials haven't experienced before become concerning. In one example, after Hurricane Florence in NC in 2018, sites where coal power plants had been throwing away their coal ash became flooded, and coal ash was introduced into floodwaters. Coal ash has been known to contain Cr(VI), which can is believed to increase chances of cancer if consumed in drinking water. Cr(VI) also occurs naturally, when it is leached from rocks in groundwater. Figuring out where Cr(VI) found in a private well is from is difficult. To determine methods of figuring out the sources of Cr(VI) we reviewed scientific literature and documented the methods that had been used before to determine Cr(VI) sources. Then, we conducted a sampling campaign across the state, and sampled 1,265 private wells from 22 different NC counties. Cr(VI) was found in many of the wells we tested, and nearly 2/3 had Cr(VI) above the level established by the NC state government as a potential health concern. From previous literature, we reviewed 51 papers and found 33 methods that had been used to determine the source of Cr(VI) in groundwater. Only five of these methods were used by more than 12 papers and while many papers used more than one method, no papers used the same grouping of methods. When we used the methods from the literature to see how the results compared between methods, they did not all agree. Three said that Cr(VI) was coming from natural sources, three indicated it came from industry, and seven made no prediction. Overall, this study shows how difficult it can be to find out the source of Cr(VI) that occurs in private wells.
Leaks in copper plumbing inside of a home or building are also not covered at all by EPA laws. The Lead and Copper Rule (LCR), passed in 1991, does include testing the water coming out of peoples' faucets for copper. But those testing results are only used to make changes at the water treatment plant to make the water less corrosive. Over the last 10-20 years, scientists have become worried that pipes may be at risk of forming more leaks, when higher hot water temperatures are used to prevent the growth of dangerous bacteria that can grow in plumbing. In one large building outside the US, at least 300 leaks were found in hot water pipes, costing large amounts of money to fix. In the past, most leaks like this were at the bottom of pipes, under settled particles with iron and manganese oxides in them. In this building though, leaks were at the top of pipes, where there was no deposit, which was very surprising. One reason for this could have been a type of reaction from past studies where iron or manganese coatings cause a reaction which forms leaks in nearby copper pipe. No experiments have ever proven this reaction though. Our study made a lab setup to learn more about this reaction and proved that it is possible and was due to manganese oxide. We found the most corrosion occurred in water with high pH and high levels of sulfate. Iron oxide particles did not cause the reaction in our study, but it is possible that other types of iron oxide could still have a role in making the reaction happen.
Past examples of cities or towns not following EPA rules has caused distrust in public drinking water. Citizens and scientists working closely together have sometimes been able to find out about such problems and get them fixed. Over the last 10 years, we have helped people learn more about their water concerns by working with them to take and analyze water tests. We documented a number of those cases which had different levels of success. The first case we talk about is Flint, MI in 2015, then St. Joseph, LA in 2016. Later cases include cities in Louisiana, South Carolina, Illinois, Oklahoma, California, and Virginia, with a number of different water risks. The first two cases caused drastic and quick changes to water safety and drinking water emergencies were declared. But after that the response was less urgent. If scientists want to pursue work with citizens who have concerns, they will need to be ready for keep working on it for a long time, and face disagreement from agencies and government groups who provide the water.
Overall, this work tried to help people, who were not being protected by government rules, or who felt that they were being harmed by governments or companies who were breaking the rules. Many of these problems make people worried about their water, or create worries that are not necessary, or cost consumers a lot of money. More work is needed to address this type of problem.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/112233 |
| Date | 19 October 2022 |
| Creators | Wait, Kory David |
| Contributors | Civil and Environmental Engineering, Edwards, Marc A., Pieper, Kelsey Janette, Widdowson, Mark A., Cai, Wenjun |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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