Thesis
Monitoring and treatment of combined radium in Iowa private wells
University of Iowa
Master of Science (MS), University of Iowa
Autumn 2021
DOI: 10.17077/etd.006288
Abstract
Unregulated private drinking water supplies, especially private wells, are likely to be disproportionately impacted by naturally-occurring radioactive material (NORM), which contaminates groundwater supplies across the United States. Well users are solely responsible for water treatment decisions, but data on well water quality is often limited. This research encompasses an investigation of two major NORM groundwater contaminants in private well water, radium-226 (226Ra) and radium-228 (228Ra). In the Upper Midwest, elevated 226Ra and 228Ra naturally occurs in groundwater, posing a possible health risk to private well users. This work encompasses one of the first high-resolution studies of the occurrence of 226Ra, 228Ra, and associated inorganic water quality parameters in private wells in Iowa. The purpose of this research is to gain an understanding of radium geochemistry in an often-overlooked water source affected by complex groundwater matrices. For the wells evaluated in this study, 53% (n = 50) measured below minimum detectable activity whereas 6.3% (n = 6) were found to contain Ra levels greater than the U.S. EPA Maximum Contaminant Level of 5 pCi/L. No associations with well depth, age, region, or water quality indicators (e.g., concentrations of other alkaline earth metals) were observed in samples with measurable activity. A resampling campaign during winter 2020 targeted 12 private wells from the 2019 survey that measured above detection for 226Ra and/or 228Ra to assess the efficacy of study participants’ in-home drinking water treatment devices at point-of-use. From a snapshot of paired indoor and outdoor samples, it was observed that water softeners and reverse osmosis reduced radium isotopes to non-detectable activity, yet other inorganic groundwater contaminants (As, Ba, and Li) persisted after treatment. This study demonstrates that Ra contamination is highly localized and occurs unpredictably in Iowa. Further, the efficacy of household water treatment technologies employed by well users merits additional assessment to ensure devices are adequately removing common inorganic groundwater contaminants. Management of radium and inorganic metal and metalloid pollutants in private well water requires knowledge of local water quality issues, regular testing at both hydrant and point-of-use, and routine evaluation and maintenance of in-home water treatment devices.
Details
- Title: Subtitle
- Monitoring and treatment of combined radium in Iowa private wells
- Creators
- Margaret Elizabeth Carolan
- Contributors
- David Cwiertny (Advisor)Tori Forbes (Advisor)Michelle Scherer (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Civil and Environmental Engineering
- Date degree season
- Autumn 2021
- DOI
- 10.17077/etd.006288
- Publisher
- University of Iowa
- Number of pages
- x, 73 pages
- Copyright
- Copyright 2021 Margaret Elizabeth Carolan
- Language
- English
- Description illustrations
- color illustrations, color maps
- Description bibliographic
- Includes bibliographical references (pages 47-59).
- Public Abstract (ETD)
Naturally-occurring radioactive materials, including radium, are common but understudied contaminants affecting unregulated water sources throughout the United States and represent a significant public health problem. These pollutants are present in high concentrations in Iowa aquifers as evidenced by measurements in groundwater-supplied public water systems and groundwater monitoring wells. Drinking water from private well systems are particularly at risk because groundwater can contain elevated concentrations of these radioactive contaminants, and well users may not employ adequate water quality monitoring tools and/or water treatment devices to remove them. This work comprises two studies of radium isotopes in private wells in Iowa to understand factors influencing the distribution of major radioactive contaminants in these water supplies. 94 wells were sampled during fall 2019 in ten Iowa counties for radium-226, radium-228, metals, metalloids, and uranium-238. Detectable concentrations of radium were randomly distributed in the samples tested and not clearly associated with other groundwater contaminants. In fall 2020, a subset of twelve private wells with detectable radium as measured in the 2019 study were resampled at both the well hydrant and the primary drinking water tap to evaluate the performance of drinking water treatment devices on the removal of major radium and uranium isotopes, as well as inorganic pollutants. Water softeners were widely used by these well users and were effective at reducing detectable radium in source water to non-detectable levels. However, several wells in this study also had issues with elevated levels of other contaminants following treatment, including arsenic, uranium, lithium, and barium. The efficacy of household water treatment technologies employed by well users merits assessment to ensure devices are adequately removing common groundwater contaminants. Management of radium and other pollutants in private well water requires knowledge of local water quality issues, regular testing at both hydrant and point-of-use, and routine evaluation and maintenance of in-home water treatment devices.
- Academic Unit
- Civil and Environmental Engineering
- Record Identifier
- 9984210528102771
Metrics
4 File views/ downloads
54 Record Views