Joseph H Hoover

Interests

Research

I am interested in how geospatial tools and technology advance our knowledge of potential human exposure to deleterious chemicals, alone and in combination using mixture analysis methods. Particular areas of interest in GIS and spatial anlysis, groundwater contaminants, abandoned uranium (and other) hardrock mines, unregulated waste disposal sites; citizen science mapping; Indigenous communities, and community-based participatory research approachs, and data report-back techniques.

Teaching

Geospatial science; spatial analysis and modeling; drinking water and water quality; exposure science; environmental health

Courses

Scholarly Contributions

Chapters

• Hoover, J., Bolt, A., Burchiel, S., Cerrato, J., Dashner-Titus, E., Erdei, E., Estrella, J., Hayek, E., Hudson, L., Luo, L., Mackenzie, D., Medina, S., Schilz, J., Velasco, C., Zychowski, K., & Lewis, J. (2021). A Transdisciplinary Approach for Studying Uranium Mobility, Exposure, and Human Health Impacts on Tribal Lands in the Southwest United States. In Practical Applications of Medical Geology. doi:10.1007/978-3-030-53893-4_6
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  The geology of the Western United States (US) is rich in mineral resources that support a diversity of ecosystems and habitats capable of sustaining significant numbers of land-based human populations. The colocation of abundant mineral resources and human populations, however, can result in significant exposures to toxic metals if natural processes or human activities mobilize these metals in the environment. In 2017, the University of New Mexico Metal Exposure and Toxicity Assessment on Tribal Lands in the Southwest (METALS) Superfund Research and Training Center brought together a diverse group of researchers to merge their historical research interests in a team science approach to address environmental and biomedical challenges associated with abandoned mine wastes on tribal lands. The goals of this SRP Center are to understand how site-specific characteristics influence the mobility of metals in the environment and resulting community-level exposures to metal mixtures and to investigate the biological mechanisms that underlie mine-waste metal toxicity, working from population through molecular mechanistic levels, and manipulating doses and mixtures in controlled animal studies. Collectively, this interdisciplinary approach aims to deepen our understanding of how toxicity develops in order to inform interventions that can help to modify those toxic responses. In this chapter, we discuss the transdisciplinary approach upon which the University of New Mexico METALS SRP is built and highlight ongoing environmental and biological research projects that deepen our knowledge of metals exposures and impacts on indigenous communities. The METALS team builds upon knowledge developed from ongoing work across three generations of impacted community members and works closely with indigenous partners to improve our understanding of current and historical resource use and exposure. Through these partnerships, the METALS team has identified key factors affecting environmental mobility of complex metal mixtures found at abandoned uranium mines and continues working to assess the resulting toxicity that can differ based on the combinations of metals in the mixtures.

Journals/Publications

• Carrol, L., Brizo, A., Clashin, D., Ingram, J., Hoover, J. H., Chief, K., Robbins, E., Janss, K., & Karanikola, V. (2025). Groundwater quality around Dillon Chapter, Navajo Nation. Arizona Cooperative Extension.
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  Document AA2107
• Erdei, E., Shuey, C., Miller, C., Hoover, J. H., Cajero, M., & Lewis, J. (2023). Metal mixture exposures and multiplexed autoantibody screening in Navajo communities exposed to uranium mine wastes. Journal of Translational Autoimmunity, 6. doi:https://doi.org/10.1016/j.jtauto.2023.100201
• Girlamo, C., Hoover, J. H., Woldeyohannes, T., Beene, D., Liu, Z., & Lin, Y. (2023). Meteorological data source comparison—a case study in geospatial modeling of potential environmental exposure to abandoned uranium mine sites in the Navajo Nation. Environmental Monitoring and Assessment, 195(7). doi:https://doi.org/10.1007/s10661-023-11283-w
• Hoover, J. H., Coker, E., Erdei, E., Luo, L., Begay, D., MacKenzie, D., Study Team, N., & Lewis, J. (2023). Preterm birth associated with metal mixture exposure among pregnant Navajo women. Environmental Health Perspectives. doi:10.1289/EHP10361
• Liu, Z., Lin, Y., Hoover, J. H., Beene, D., Singer, N., & Charley, P. (2023). Individual level spatial-temporal modeling of exposure potential of livestock in the Cove Wash Watershed, Arizona. Annals of GIS, 1-21. doi:https://doi.org/10.1080/19475683.2022.2075935
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  Personal exposure studies suffer from uncertainty issues, largely stemming from individual behaviour uncertainties. Built on spatial-temporal exposure analysis and methods, this study proposed a novel approach to spatial-temporal modelling that incorporated behaviour classifications taking into account uncertainties, to estimate individual livestock exposure potential. The new approach was applied in a community-based research project with a Tribal community in the southwest United States to address questions on potential livestock exposure to abandoned uranium mines (AUMs). The study aimed to 1) classify Global Positioning System (GPS) data from livestock into three behaviour subgroups – grazing, travelling or resting; 2) calculate the daily cumulative exposure potential for livestock; 3) assess the performance of the computational method with and without behaviour classifications. Using Lotek Litetrack GPS collars, we collected data at a 20-min-interval for two flocks of sheep and goats during the spring and summer of 2019. Analysis and modelling of GPS data demonstrated no significant difference in individual cumulative exposure potential within each flock when animal behaviours with probability/uncertainties were considered. However, when daily cumulative exposure potential was calculated without consideration of animal behaviour or probability/uncertainties, significant differences among animals within a herd were observed, which does not match animal grazing behaviours reported by livestock owners. These results suggest that the proposed method including behaviour subgroups with probability/uncertainties more closely resembled the observed grazing behaviours. Results from the research may be used for future intervention and policy-making on remediation efforts in communities where grazing livestock may encounter environmental contaminants.
• Hoover, J. H., Been, D., & Chief, K. (2022). A team-science approach to address water quality and security challenges and COVID-19 on the Navajo Nation. Water Resources IMPACT, 24(1), 5-9.
• Nozadi, S., Li, L., Luo, L., Mackenzie, D., Erdei, E., Du, R., Roman, C., Hoover, J., Burnette, C., Lewis, J., & O’donald, E. (2022). Prenatal metal exposures and infants’ developmental outcomes in a navajo population. International Journal of Environmental Research and Public Health, 19(1). doi:10.3390/ijerph19010425
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  Early-life exposure to environmental toxicants can have detrimental effects on children’s neurodevelopment. In the current study, we employed a causal modeling framework to examine the direct effect of specific maternal prenatal exposures on infants’ neurodevelopment in the context of co-occurring metals. Maternal metal exposure and select micronutrients’ concentrations were assessed using samples collected at the time of delivery from mothers living across Navajo Nation with community exposure to metal mixtures originating from abandoned uranium mines. Infants’ development across five domains was measured at ages 10 to 13 months using the Ages and Stages Questionnaire Inventory (ASQ:I), an early developmental screener. After adjusting for effects of other confounding metals and demographic variables, prenatal exposure to lead, arsenic, antimony, barium, copper, and molybdenum predicted deficits in at least one of the ASQ:I domain scores. Strontium, tungsten, and thallium were positively associated with several aspects of infants’ development. Mothers with lower socioeconomic status (SES) had higher lead, cesium, and thallium exposures compared to mothers from high SES backgrounds. These mothers also had infants with lower scores across various developmental domains. The current study has many strengths including its focus on neurodevelopmental outcomes during infancy, an understudied developmental period, and the use of a novel analytical method to control for the effects of co-occurring metals while examining the effect of each metal on neurodevelopmental outcomes. Yet, future examination of how the effects of prenatal exposure on neurodevelopmental outcomes unfold over time while considering all potential interactions among metals and micronutrients is warranted.
• Lin, Y., Lippitt, C., Beene, D., & Hoover, J. (2021). Impact of travel time uncertainties on modeling of spatial accessibility: a comparison of street data sources. Cartography and Geographic Information Science, 48(6). doi:10.1080/15230406.2021.1960609
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  GIS-based spatial access measures have been used extensively to monitor social equity and to help develop policy. However, inherent uncertainties in the road datasets used in spatial access estimates remain largely underreported. These uncertainties might result in unrecognized biases within visualization products and decision-making outcomes that strive to improve social equity based on seemingly egalitarian accessibility metrics. To better understand and address these uncertainties, we evaluated variations in travel impedance for car and bus transportation using proprietary, volunteer-information-based, and free (non-volunteer-information-based) street networks. We then interpreted the measured variations through the lens of street data uncertainty and its propagation in a common E2SFCA model of spatial accessibility. Results indicated that travel impedance disagreement propagates through the modeling process to effect agreement of spatial access index (SPAI) estimates among different street sources, with larger uncertainties observed for bus travel than car travel. Higher impedance coefficients (β), a model parameter, reduced the impact of street-source variations on estimates. Less urbanized regions were found to experience higher street-source variations when compared with the core-metropolitan area. We also demonstrated that a relative spatial access measure–the spatial access ratio (SPAR)–reduced uncertainties introduced by the choice of street datasets. Careful selection of reliable street sources and model parameters (e.g. higher β), as well as consideration of the potential for bias, particularly for less urbanized areas and areas reliant on public transportation, is warranted when leveraging SPAI to inform policy. When reliable/accurate road network data are not accessible or data quality information is not available, the SPAR is a suitable alternative or supplement to SPAI for visualization and analyses.
• De La Rosa, V., Hoover, J., Du, R., Jimenez, E., MacKenzie, D., & Lewis, J. (2020). Diet quality among pregnant women in the Navajo Birth Cohort Study. Maternal and Child Nutrition, 16(3). doi:10.1111/mcn.12961
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  Proper nutrition during pregnancy is vital to maternal health and fetal development and may be challenging for Navajo Nation residents because access to affordable and healthy foods is limited. It has been several decades since reported diet quality during pregnancy was examined on Navajo Nation. We present the first study to estimate iodine intake and use the Healthy Eating Index (HEI-2015) to assess maternal diet quality among pregnant women in the Navajo Birth Cohort Study (NBCS). Based on dietary intake data derived from food frequency questionnaires, overall estimated micronutrient intake has remained similar since the last assessment in 1981, with potential improvements evident for folate and niacin. A high proportion of women (>50%) had micronutrient intakes from dietary sources below the Estimated Average Requirements during pregnancy. The median urinary iodine concentration for NBCS women (90.8 μg/L; 95% CI [80, 103.5]) was less than adequate and lower than concentrations reported for pregnant women that participated in the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014. Overall, average diet quality of NBCS women estimated using the HEI-2015 (62.4; 95% CI [60.7, 64.0]) was similar to that reported for women of child-bearing age and pregnant women in NHANES. Although, NBCS women had diets high in added sugar, with sugar-sweetened beverages as the primary contributors. Our study provides updated insights on maternal diet quality that can inform health and nutrition initiatives in Navajo communities emphasizing nutrition education and access to prenatal vitamins and calcium, iodine, and vitamin E dense foods.
• Hoover, J., Erdei, E., Begay, D., Gonzales, M., Jarrett, J., Cheng, P., & Lewis, J. (2020). Exposure to uranium and co-occurring metals among pregnant Navajo women. Environmental Research, 190. doi:10.1016/j.envres.2020.109943
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  Navajo Nation residents are at risk for exposure to uranium and other co-occurring metals found in abandoned mine waste. The Navajo Birth Cohort Study (NBCS) was initiated in 2010 to address community concerns regarding the impact of chronic environmental exposure to metals on pregnancy and birth outcomes. The objectives of this paper were to 1) evaluate maternal urine concentrations of key metals at enrollment and delivery from a pregnancy cohort; and 2) compare the NBCS to the US general population by comparing representative summary statistical values. Pregnant Navajo women (N = 783, age range 14–45 years) were recruited from hospital facilities on the Navajo Nation during prenatal visits and urine samples were collected by trained staff in pre-screened containers. The U.S. Centers for Disease Control and Prevention (CDC), National Center for Environmental Health's (NCEH) Division of Laboratory Sciences (DLS) analyzed urine samples for metals. Creatinine-corrected urine concentrations of cadmium decreased between enrollment (1st or 2nd trimester) and delivery (3rd trimester) while urine uranium concentrations were not observed to change. Median and 95th percentile values of maternal NBCS urine concentrations of uranium, manganese, cadmium, and lead exceeded respective percentiles for National Health and Nutrition Evaluation Survey (NHANES) percentiles for women (ages 14–45 either pregnant or not pregnant.) Median NBCS maternal urine uranium concentrations were 2.67 (enrollment) and 2.8 (delivery) times greater than the NHANES median concentration, indicating that pregnant Navajo women are exposed to metal mixtures and have higher uranium exposure compared to NHANES data for women. This demonstrates support for community concerns about uranium exposure and suggests a need for additional analyses to evaluate the impact of maternal metal mixtures exposure on birth outcomes.
• Lin, Y., Hoover, J., Beene, D., Erdei, E., & Liu, Z. (2020). Environmental risk mapping of potential abandoned uranium mine contamination on the Navajo Nation, USA, using a GIS-based multi-criteria decision analysis approach. Environmental Science and Pollution Research, 27(24). doi:10.1007/s11356-020-09257-3
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  The Navajo Nation (NN), a sovereign indigenous tribal nation in the Southwestern United States, is home to 523 abandoned uranium mines (AUMs). Previous health studies have articulated numerous human health hazards associated with AUMs and multiple environmental mechanisms/pathways (e.g., air, water, and soil) for contaminant transport. Despite this evidence, the limited modeling of AUM contamination that exists relies solely on proximity to mines and only considers single rather than combined pathways from which the contamination is a product. In order to better understand the spatial dynamics of contaminant exposure across the NN, we adopted the following established geospatial and computational methods to develop a more sophisticated environmental risk map illustrating the potential for AUM contamination: GIS-based multi-criteria decision analysis (GIS-MCDA), fuzzy logic, and analytic hierarchy process (AHP). Eight criteria layers were selected for the GIS-MCDA model: proximity to AUMs, roadway proximity, drainage proximity, topographic landforms, wind index, topographic wind exposure, vegetation index, and groundwater contamination. Model sensitivity was evaluated using the one-at-a-time method, and statistical validation analysis was conducted using two separate environmental datasets. The sensitivity analysis indicated consistency and reliability of the model. Model results were strongly associated with environmental uranium concentrations. The model classifies 20.2% of the NN as high potential for AUM contamination while 65.7% and 14.1% of the region are at medium and low risk, respectively. This study is entirely a novel application and a crucial first step toward informing future epidemiologic studies and ongoing remediation efforts to reduce human exposure to AUM waste.
• Scammell, M., Sennett, C., Laws, R., Rubin, R., Brooks, D., Amador, J., Ramirez-Rubio, O., Friedman, D., McClean, M., Lewis, J., Erdei, E., Begay, D., Cajero, M., Chavez, C., Hoover, J., Laselute, C., Mackenzie, D., Pacheco, B., Smith, B., , Anderson, Q., et al. (2020). Urinary metals concentrations and biomarkers of autoimmunity among navajo and nicaraguan men. International Journal of Environmental Research and Public Health, 17(15). doi:10.3390/ijerph17155263
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  Metals are suspected contributors of autoimmune disease among indigenous Americans. However, the association between metals exposure and biomarkers of autoimmunity is under-studied. In Nicaragua, environmental exposure to metals is also largely unexamined with regard to autoimmunity. We analyzed pooled and stratified exposure and outcome data from Navajo (n = 68) and Nicaraguan (n = 47) men of similar age and health status in order to characterize urinary concentrations of metals, compare concentrations with the US National Health and Nutrition Examination Survey (NHANES) male population, and examine the associations with biomarkers of autoimmunity. Urine samples were analyzed for metals via inductively coupled plasma mass spectrometry (ICP-MS) at the US Centers for Disease Control and Prevention. Serum samples were examined for antinuclear antibodies (ANA) at 1:160 and 1:40 dilutions, using an indirect immunofluorescence assay and for specific autoantibodies using enzyme-linked immunosorbent assay (ELISA). Logistic regression analyses evaluated associations of urinary metals with autoimmune biomarkers, adjusted for group (Navajo or Nicaraguan), age, and seafood consumption. The Nicaraguan men had higher urinary metal concentrations compared with both NHANES and the Navajo for most metals; however, tin was highest among the Navajo, and uranium was much higher in both populations compared with NHANES. Upper tertile associations with ANA positivity at the 1:160 dilution were observed for barium, cesium, lead, strontium and tungsten.
• Dashner-Titus, E., Hoover, J., Li, L., Lee, J., Du, R., Liu, K., Traber, M., Ho, E., Lewis, J., & Hudson, L. (2018). Metal exposure and oxidative stress markers in pregnant Navajo Birth Cohort Study participants. Free Radical Biology and Medicine, 124. doi:10.1016/j.freeradbiomed.2018.04.579
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  Contamination of soil and water by waste from abandoned uranium mines has led to chronic exposures to metal mixtures in Native American communities. Our previous work demonstrated that community exposures to mine waste increase the likelihood of developing cardiovascular disease, as well as the likelihood of developing multiple chronic diseases including diabetes, hypertension and kidney disease. Exposure to various environmental metals is associated with elevated oxidative stress, which is considered a contributor to these and other chronic disease states. The purpose of the current research was to assess potential associations between exposure to uranium and arsenic and evidence for increased oxidative stress as measured by urinary F2 -isoprostanes in pregnant women enrolled in the Navajo Birth Cohort Study. The current study also included an analysis of zinc as a potential mediator of oxidative stress in the study population. Urinary arsenic and uranium, serum zinc and urinary F2 -isoprostanes were measured for each study participant at enrollment. Study participants were pregnant women with median age of 26.8; 18.9% were enrolled in the 1st trimester, 44.7% were enrolled in the 2nd trimester, and 36.4% were enrolled in the 3rd trimester. Median urinary metal levels were 5.5 and 0.016 µg/g creatinine for arsenic and uranium, respectively. Multivariable regression analysis indicated a significant association between arsenic exposure and the lipid peroxidation product 8-iso-prostaglandin F2α controlling for zinc and trimester. No associations were detected with uranium despite evidence that levels were in the Navajo Birth Cohort samples were 2.3 times the median reported for women in the National Health and Nutrition Examination Survey (2011-12). Zinc was not found to have any causal mediation of the effects of the other metals on oxidative stress. The current work is consistent with other studies that have detected an association between arsenic and elevated oxidative stress. In contrast to arsenic, uranium did not appear to increase oxidative stress response in this study population. These findings are relevant to assessing the potential human impact of chronic exposure to mixed metal waste from abandoned uranium mines.
• Eggers, M., Doyle, J., Lefthand, M., Young, S., Moore-Nall, A., Kindness, L., Medicine, R., Ford, T., Dietrich, E., Parker, A., Hoover, J., & Camper, A. (2018). Community engaged cumulative risk assessment of exposure to inorganic well water contaminants, crow reservation, Montana. International Journal of Environmental Research and Public Health, 15(1). doi:10.3390/ijerph15010076
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  An estimated 11 million people in the US have home wells with unsafe levels of hazardous metals and nitrate. The national scope of the health risk from consuming this water has not been assessed as home wells are largely unregulated and data on well water treatment and consumption are lacking. Here, we assessed health risks from consumption of contaminated well water on the Crow Reservation by conducting a community-engaged, cumulative risk assessment. Well water testing, surveys and interviews were used to collect data on contaminant concentrations, water treatment methods, well water consumption, and well and septic system protection and maintenance practices. Additive Hazard Index calculations show that the water in more than 39% of wells is unsafe due to uranium, manganese, nitrate, zinc and/or arsenic. Most families’ financial resources are limited, and 95% of participants do not employ water treatment technologies. Despite widespread high total dissolved solids, poor taste and odor, 80% of families consume their well water. Lack of environmental health literacy about well water safety, pre-existing health conditions and limited environmental enforcement also contribute to vulnerability. Ensuring access to safe drinking water and providing accompanying education are urgent public health priorities for Crow and other rural US families with low environmental health literacy and limited financial resources.
• Harmon, M., Lewis, J., Miller, C., Hoover, J., Ali, A., Shuey, C., Cajero, M., Lucas, S., Pacheco, B., Erdei, E., Ramone, S., Nez, T., Campen, M., & Gonzales, M. (2018). Arsenic association with circulating oxidized low-density lipoprotein in a Native American community. Journal of Toxicology and Environmental Health - Part A: Current Issues, 81(13). doi:10.1080/15287394.2018.1443860
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  More than 500 abandoned uranium (U) mines within the Navajo Nation contribute U, arsenic (As) and other metals to groundwater, soil and potentially air through airborne transport. The adverse cardiovascular health effects attributed to cumulative exposure to these metals remains uncertain. The aim of this study was to examine whether environmental exposure to these metals may promote or exacerbate the oxidation of low-density lipoprotein (LDL) cholesterol in this Native American population. The correlation of cardiovascular biomarkers (oxidized LDL (oxLDL) and C-reactive protein (CRP)) from a Navajo cohort (n = 252) with mean annual As and U intakes from water and urine metals was estimated using linear regression. Proof-of-concept assays were performed to investigate whether As and U directly oxidize human LDL. Mean annual As intake from water was positively and significantly associated with oxLDL, but not CRP in this study population, while U intake estimates were negatively associated with oxLDL. In an acellular system, As, but not U, directly oxidized the apolipoprotein B-100 component of purified human LDL. Neither metal promoted lipid peroxidation of the LDL particle. Both the population and lab results are consistent with the hypothesis that As promotes oxidation of LDL, a crucial step in vascular inflammation and chronic vascular disease. Conversely, for outcomes related to U, negative associations were observed between U intake and oxLDL, and U only minimally altered human LDL in direct exposure experiments. Only urine U was correlated with CRP, whereas no other metals in water or urine were apparently reliable predictors of this inflammatory marker.
• Hoover, J., Coker, E., Barney, Y., Shuey, C., & Lewis, J. (2018). Spatial clustering of metal and metalloid mixtures in unregulated water sources on the Navajo Nation – Arizona, New Mexico, and Utah, USA. Science of the Total Environment, 633. doi:10.1016/j.scitotenv.2018.02.288
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  Contaminant mixtures are identified regularly in public and private drinking water supplies throughout the United States; however, the complex and often correlated nature of mixtures makes identification of relevant combinations challenging. This study employed a Bayesian clustering method to identify subgroups of water sources with similar metal and metalloid profiles. Additionally, a spatial scan statistic assessed spatial clustering of these subgroups and a human health metric was applied to investigate potential for human toxicity. These methods were applied to a dataset comprised of metal and metalloid measurements from unregulated water sources located on the Navajo Nation, in the southwest United States. Results indicated distinct subgroups of water sources with similar contaminant profiles and that some of these subgroups were spatially clustered. Several profiles had metal and metalloid concentrations that may have potential for human toxicity including arsenic, uranium, lead, manganese, and selenium. This approach may be useful for identifying mixtures in water sources, spatially evaluating the clusters, and help inform toxicological research investigating mixtures.
• Lin, Y., Wimberly, M., Da Rosa, P., Hoover, J., & Athas, W. (2018). Geographic access to radiation therapy facilities and disparities of early-stage breast cancer treatment. Geospatial Health, 13(1). doi:10.4081/gh.2018.622
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  Few studies of breast cancer treatment have focused on the Northern Plains of the United States, an area with a high mastectomy rate. This study examined the association between geographic access to radiation therapy facilities and receipt of breast cancer treatments among early-stage breast cancer patients in South Dakota. Based on 4,209 early-stage breast cancer patients diagnosed between 2001 and 2012 in South Dakota, the study measured geographic proximity to radiation therapy facilities using the shortest travel time for patients to the closest radiation therapy facility. Two-level logistic regression models were used to estimate for early stage cases i) the odds of mastectomy versus breast conserving surgery (BCS); ii) the odds of not receiving radiation therapy after BCS versus receiving follow-up radiation therapy. Covariates included race/ethnicity, age at diagnosis, tumour grade, tumour sequence, year of diagnosis, census tract-level poverty rate and urban/rural residence. The spatial scan statistic method was used to identify geographic areas with significantly higher likelihood of experiencing mastectomy. The study found that geographic accessibility to radiation therapy facilities was negatively associated with the likelihood of receiving mastectomy after adjustment for other covariates, but not associated with radiation therapy use among patients receiving BCS. Compared with patients travelling less than 30 minutes to a radiation therapy facility, patients travelling more than 90 minutes were about 1.5 times more likely to receive mastectomy (odds ratio, 1.51; 95% confidence interval, 1.08-2.11) and patients travelling more than 120 minutes were 1.7 times more likely to receive mastectomy (odds ratio, 1.70; 95% confidence interval, 1.19-2.42). The study also identified a statistically significant cluster of patients receiving mastectomy who were located in south-eastern South Dakota, after adjustment for other factors. Because geographic proximity to treatment facilities plays an important role on the treatment for early-stage breast cancer patients, this study has important implications for developing targeted intervention to reduce disparities in breast cancer treatment in South Dakota.
• Harmon, M., Lewis, J., Miller, C., Hoover, J., Ali, A., Shuey, C., Cajero, M., Lucas, S., Zychowski, K., Pacheco, B., Erdei, E., Ramone, S., Nez, T., Gonzales, M., & Campen, M. (2017). Residential proximity to abandoned uranium mines and serum inflammatory potential in chronically exposed Navajo communities. Journal of Exposure Science and Environmental Epidemiology, 27(4). doi:10.1038/jes.2016.79
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  Members of the Navajo Nation, who possess a high prevalence of cardiometabolic disease, reside near hundreds of local abandoned uranium mines (AUM), which contribute uranium, arsenic and other metals to the soil, water and air. We recently reported that hypertension is associated with mine waste exposures in this population. Inflammation is a major player in the development of numerous vascular ailments. Our previous work establishing that specific transcriptional responses of cultured endothelial cells treated with human serum can reveal relative circulating inflammatory potential in a manner responsive to pollutant exposures, providing a model to assess responses associated with exposure to these waste materials in this population. To investigate a potential link between exposures to AUM and serum inflammatory potential in affected communities, primary human coronary artery endothelial cells were treated for 4 h with serum provided by Navajo study participants (n=145). Endothelial transcriptional responses of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and chemokine ligand 2 (CCL2) were measured. These transcriptional responses were then linked to AUM exposure metrics, including surface area-weighted AUM proximity and estimated oral intake of metals. AUM proximity strongly predicted endothelial transcriptional responses to serum including CCL2, VCAM-1 and ICAM-1 (P
• Hoover, J., Gonzales, M., Shuey, C., Barney, Y., & Lewis, J. (2017). Elevated arsenic and uranium concentrations in unregulated water sources on the Navajo Nation, USA. Exposure and Health, 9(2). doi:10.1007/s12403-016-0226-6
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  Regional water pollution and use of unregulated water sources can be an important mixed metals exposure pathway for rural populations located in areas with limited water infrastructure and an extensive mining history. Using censored data analysis and mapping techniques we analyzed the joint geospatial distribution of arsenic and uranium in unregulated water sources throughout the Navajo Nation, where over 500 abandoned uranium mine sites are located in the rural southwestern United States. Results indicated that arsenic and uranium concentrations exceeded national drinking water standards in 15.1% (arsenic) and 12.8% (uranium) of tested water sources. Unregulated sources in close proximity (i.e., within 6 km) to abandoned uranium mines yielded significantly higher concentrations of arsenic or uranium than more distant sources. The demonstrated regional trends for potential co-exposure to these chemicals have implications for public policy and future research. Specifically, to generate solutions that reduce human exposure to water pollution from unregulated sources in rural areas, the potential for co-exposure to arsenic and uranium requires expanded documentation and examination. Recommendations for prioritizing policy and research decisions related to the documentation of existing health exposures and risk reduction strategies are also provided.
• Rodriguez-Freire, L., Avasarala, S., Ali, A., Agnew, D., Hoover, J., Artyushkova, K., Latta, D., Peterson, E., Lewis, J., Crossey, L., Brearley, A., & Cerrato, J. (2016). Post Gold King Mine Spill Investigation of Metal Stability in Water and Sediments of the Animas River Watershed. Environmental Science and Technology, 50(21). doi:10.1021/acs.est.6b03092
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  We applied spectroscopy, microscopy, diffraction, and aqueous chemistry methods to investigate the persistence of metals in water and sediments from the Animas River 13 days after the Gold King Mine spill (August 5, 2015). The Upper Animas River watershed, located in San Juan Colorado, is heavily mineralized and impacted by acid mine drainage, with low pH water and elevated metal concentrations in sediments (108.4 ± 1.8 mg kg-1 Pb, 32.4 ± 0.5 mg kg-1 Cu, 729.6 ± 5.7 mg kg-1 Zn, and 51 314.6 ± 295.4 mg kg-1 Fe). Phosphate and nitrogen species were detected in water and sediment samples from Farmington, New Mexico, an intensive agricultural area downstream from the Animas River, while metal concentrations were low compared to those observed upstream. Solid-phase analyses of sediments suggest that Pb, Cu, and Zn are associated with metal-bearing jarosite and other minerals (e.g., clays, Fe-(oxy)hydroxides). The solubility of jarosite at near-neutral pH and biogeochemical processes occurring downstream could affect the stability of metal-bearing minerals in river sediments. This study contributes relevant information about the association of metal mixtures in a heavy mineralized semiarid region, providing a foundation to better understand long-term metal release in a public and agricultural water supply.
• Hoover, J., Sutton, P., Anderson, S., & Keller, A. (2014). Designing and evaluating a groundwater quality Internet GIS. Applied Geography, 53. doi:10.1016/j.apgeog.2014.06.005
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  Contaminated unregulated drinking water in rural communities is a continuing health issue, leading many resource users to unknowingly consume water with elevated levels of harmful chemicals. Though geographic information systems (GIS) and Internet technology have been particularly useful for water resource management, to date, there exist few studies that specifically address the development of Internet-based GIS applications to increase user access to unregulated drinking water source information. Informed by an existing user centered development framework for Internet mapping, we created an Internet GIS that visualized groundwater contamination on the Navajo Nation in the southwest United States. We employed a usability focus group, expert review of content and pilot test of a prototype GIS application to gather empirical evidence on effectiveness for informing users of a significant water quality issue. Results suggested that the designed and deployed GIS application was appropriate for the target audience of environmental nongovernmental organization (ENGO) and institution of higher education (IHE) professionals. Usability testing and expert review confirmed the importance of these evaluation measures to ensure a high quality GIS prior to deployment. Use of existing Internet mapping guidelines was found to be insufficient for creating a refined GIS interface appropriate for the target audience. Additionally, we demonstrated that an existing user centered design and evaluation framework could be applied successfully to visualize water quality for unregulated groundwater wells in the rural southwest United States. Suggestions for continued research in the use of Internet GIS to inform rural residents about drinking water quality are provided. © 2014 Elsevier Ltd.
• Hale, R., Hoover, J., Wollheim, W., & Vörösmarty, C. (2013). History of nutrient inputs to the northeastern United States, 1930-2000. Global Biogeochemical Cycles, 27(2). doi:10.1002/gbc.20049
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  Humans have dramatically altered nutrient cycles at local to global scales. We examined changes in anthropogenic nutrient inputs to the northeastern United States (NE) from 1930 to 2000. We created a comprehensive time series of anthropogenic N and P inputs to 437 counties in the NE at 5 year intervals. Inputs included atmospheric N deposition, biological N2 fixation, fertilizer, detergent P, livestock feed, and human food. Exports included exports of feed and food and volatilization of ammonia. N inputs to the NE increased throughout the study period, primarily due to increases in atmospheric deposition and fertilizer. P inputs increased until 1970 and then declined due to decreased fertilizer and detergent inputs. Livestock consistently consumed the majority of nutrient inputs over time and space. The area of crop agriculture declined during the study period but consumed more nutrients as fertilizer. We found that stoichiometry (N:P) of inputs and absolute amounts of N matched nutritional needs (livestock, humans, crops) when atmospheric components (N deposition, N2 fixation) were not included. Differences between N and P led to major changes in N:P stoichiometry over time, consistent with global trends. N:P decreased from 1930 to 1970 due to increased inputs of P, and increased from 1970 to 2000 due to increased N deposition and fertilizer and decreases in P fertilizer and detergent use. We found that nutrient use is a dynamic product of social, economic, political, and environmental interactions. Therefore, future nutrient management must take into account these factors to design successful and effective nutrient reduction measures. Key Points Spatiotemporal patterns of nutrient inputs were dynamic and unique for N and P. Livestock consume the majority of nutrient inputs to the NE. Human population density best predictor of nutrient inputs. © 2013. American Geophysical Union. All Rights Reserved.
• Scott, C., Pierce, S., Pasqualetti, M., Jones, A., Montz, B., & Hoover, J. (2011). Policy and institutional dimensions of the water-energy nexus. Energy Policy, 39(10). doi:10.1016/j.enpol.2011.08.013
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  Energy and water are interlinked. The development, use, and waste generated by demand for both resources drive global change. Managing them in tandem offers potential for global-change adaptation but presents institutional challenges. This paper advances understanding of the water-energy nexus by demonstrating how these resources are coupled at multiple scales, and by uncovering institutional opportunities and impediments to joint decision-making. Three water-energy nexus cases in the United States are examined: (1) water and energy development in the water-scarce Southwest; (2) conflicts between coal development, environmental quality, and social impacts in the East; and (3) tensions between environmental quality and economic development of shale natural gas in the Northeast and Central U.S. These cases are related to Eastern, Central, and Western regional stakeholder priorities collected in a national effort to assess energy-water scenarios. We find that localized challenges are diminished when considered from broader perspectives, while regionally important challenges are not prioritized locally. The transportability of electricity, and to some extent raw coal and gas, makes energy more suitable than water to regionalized global-change adaptation, because many of the impacts to water availability and quality remain localized. We conclude by highlighting the need for improved coordination between water and energy policy. © 2011 Elsevier Ltd.

Proceedings Publications

• Estacio, I., Hoover, J., Li, X., Lim, C., & Román-Palacios, C. (2024). Open-source automatic extraction of Urban Green Space: Application to assessing improvement in green space access. In The Role of Photogrammetry for a Sustainable World.
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  Urban Green Space (UGS) is vital for improving the public health and sustainability of cities. Vector data on UGS such as open data from governments and OpenStreetMap are available for retrieval by interested users, but the availability of UGS data is still limited on global and temporal scales. This study develops the UGS Extractor, a web-based application for the automatic extraction of UGS given user inputs of Area of Interest and Date of Interest. To accommodate various types of green spaces, such as parks or lawns, the application additionally allows users to set parameters for the minimum size of each UGS and the Minimum Urban Neighbor Density, enabling customization of what qualifies as UGS. The UGS Extractor implements a methodological framework that applies object-based image processing, edge detection and extraction, and image neighborhood analysis on the near real-time 10m Dynamic World collection of Land Use/Land Cover images. The application's utility was demonstrated through two case studies. In the first, the UGS Extractor accurately mapped major parks when compared to open data sources in New Orleans, USA. In the second, the UGS Extractor demonstrated significant increases in the total area of UGS from 2015 to 2023 in Songdo, South Korea, which consequently improved green space accessibility. These results underscore the UGS Extractor's utility in extracting specific types of UGS and analyzing their temporal trends. This user-friendly application overall offers higher spatial resolution compared to publicly available satellite-based methods while facilitating temporal studies not possible with vector datasets.

Presentations

• Hoover, J. H. (2024, April). GIS database management for TCLs and protecting data sovereignty. West Coast Tribal Cultural Landscapes Intertribal Working Group. Sacramento, CA: Udall Foundation.
• Hoover, J. H. (2024, February). Building and Sustaining Local Capacities. Partnerships for Environmental Public Health 2024 Conference. Research Triangle Park, NC: NIEHS.
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  Invited panelist, unable to participate due to illness.
• Hoover, J. H. (2024, June). Environmental connections with human health. Beyond Cancer. Pascua Yaqui, Tucson, AZ: University of Arizona Cancer Center and the Indigenous Resilience Center.
• Hoover, J. H. (2024, March). Supporting Indigenous environmental health using geospatial technologies. ConocoPhillips Geography Career Spotlight Speaker. Stillwater, OK: Oklahoma State University.
• Hoover, J. H. (2024, October). Centering Community values and voice in environmental science research. 2024 Society for Advancing Chicanos/Hispanics and Native Americans in Science (SACNAS) Annual Meeting. Phoenix, AZ: SACNAS.
• Hoover, J. H. (2024, September). Community-engaged climate change and health research with SCORCH. 2024 NIEHS Environmental Health Sciences Core Centers Annual Meeting. Baltimore, MD: Johns Hopkins University.
• Hoover, J. H., & Erdei, E. (2024, April). Uupdates on CRST Tribal environmental health research in the P50 Native Environmental Health Equity Center. Wellness & Research in Indian Country Symposium. Rapid City, SD: Missouri Breaks Industries Research, Inc.
• Hoover, J. H., & MacKenzie, D. (2024, February). Updates from the Center for Native Environmental Health Equity Research. 2024 Centers of Excellence for Environmental Health Disparities Annual Meeting. Research Triangle Park, NC: Baylor University.
• Hoover, J. H., & Woldeyohannes, T. (2024, June). What's in that awful smelling smoke?. Crow Water Quality Project Community Open House. Crow Agency, MT: Crow Water Quality Project, Little Big Horn College.
• Hoover, J. H. (2023, April). An overview of the Navajo Water GIS Application. Water is Life Webinar. Zoom: New Mexico Social Justice and Equity Institute.
• Hoover, J. H. (2023, Fall). Addressing water data gaps through community-engaged projects. Native Voices in STEM. Tucson, AZ/Zoom: Indigenous Resilience Center.
• Hoover, J. H. (2023, Spring). Geospatial methods for community driven environmental health disparities research with Indigenous communities. Spring Seminar for School of Geography and Regional Development, University of Arizona. Tucson, AZ: School of Geography and Regional Development, University of Arizona.
• Hoover, J. H. (2023, Spring). Spatial patterns of human exposure to environmental pollutants in abandoned mine lands. Spring Seminar for the University of Arizona Superfund Research Center. Tucson, AZ: University of Arizona Superfund Research Center.
• Hoover, J. H. (2023, Spring). What’s in that awful smelling smoke?. Crow Water Quality Project Open House,. Crow Agency, MT: Crow Water Quality Project, Little Big Horn College.
• Hoover, J. H., & Erdei, E. (2023, April). Updates from the Center For Native Environmental Health Equity Research. Cheyenne River Sioux Tribe Community Research Symposium. Eagle Butte, SD: Missour Breaks Research Industries, Inc.
• Hoover, J. H., Beene, D., & Matiukaite, S. (2023, July). Using mobile applications to visualize water quality data for underserved communities. Arizona Water Resources Research Center Annual Conference. Tucson, AZ: Arizona Water Resources Research Center.
• Hoover, J. H., Ingram, J., Akee, R., Beene, D., Tulley, N., Gray, B., Chee, R., Shuey, C., Carroll, S. R., Lewis, J., & Chief, K. (2023, March). Assessing COVID-19 risk factors on the Navajo Nation - Preliminary Results. 2023 American Association of Geographers. Denver, CO: American Association of Geographers.
• Robinson, D., Hoover, J. H., Ingram, J., & Lin, Y. (2023, Spring). Cove livestock study: Update to USEPA Region 9, project close out presentation. EPA Region 9 Monthly Team Meeting. San Francisco, CA/Zoom: US Environmental Protection Agency.
• Shuey, C., Dixson, E., Sethuraman, A., Tsotie, K., & Hoover, J. H. (2023, Fall). Updates on Sanders Water Quality Project: Testing results and next steps. Nahata Dziil Commission Governance (New Lands Chapter, Navajo Nation) Meeting. Sanders, AZ: Nahata Dziil Commission Governance (New Lands Chapter, Navajo Nation).
• Hoover, J. H. (2022, May). Tribal household water security on the Navajo Nation – A review of existing studies. 2022 Interdisciplinary Workshop - Water in the West: Toward Convergent Solutions to Water Security. Bozeman, MT: Montana State University.
• Hoover, J. H. (2022, October). GIS and Environmental Science. Guest Lecture, ENVS 210. Tucson, AZ: ENVS Instructor Katrina Henry.
• Hoover, J. H., & Lin, Y. (2022, May). Results of Animal Collaring and Spatial Analysis of the Cove Livestock Study. Diné College NSF TCUP 2022 Summer Internship Program Meeting. Virtual: Dine College.
• Hoover, J. H., Gonzales, M., & Erdei, E. (2022, July). Community-informed practices for assessing exposure to pollutants generated from inadequate solid waste management. Plastics and Human Health Virtual Webinar. Virtual: National Institute of Environmental Health Science Partnerships for Environmental Public Health.
• Hoover, J. H., Lin, Y., & Erdei, E. (2022, November). Updates about the Center For Native Environmental Health Research for the Crow Environmental Health Steering Committee. Quarterly Meeting of the Crow Environmental Health Streering Committee. Bozeman, MT: Crow Environmental Health Steering Committee.
• Hoover, J. H., Lin, Y., & James, L. (2022, August). Updates on the Blue Gap/Tachee Livestock Study. August Chapter Meeting, Blue Gap/Tachee Chapter, Navajo Nation. Virtual: Blue Gap/Tachee Chapter.
• Hoover, J. H., Lin, Y., & James, L. (2022, September). Updates on the Blue Gap/Tachee Livestock Study. September Chapter Meeting, Blue Gap/Tachee Chapter, Navajo Nation. Virtual: Blue Gap/Tachee Chapter.
• Hoover, J. H., Mackenzie, D., & Lewis, J. (2022, December). Updates on the Center for Native Environmental Health Equity Research. 2022 Centers of Excellence for Environmental Health Disparities Annual Meeting (Virtual). Virtual: National Institute for Minority Health and Health Disparities.
• Lin, Y., & Hoover, J. H. (2022, November). Applying Geospatial Tools and Technology to Implement Community Driven Environmental Health Disparities Research with Indigenous Communities. STEM Events: See yourself in STEM Workshop Series. Virtual: Bunker Hill Community College (Boston, MA), Louis Stokes Alliances for Minority Participation (LSAMP).
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  Joint presentation by myself and Dr. Lin

Poster Presentations

• Castro, A., Sethuraman, A., & Hoover, J. H. (2023, December). Seasonal Variation of Uranium in the Puerco River Basin. American Geophysical Union Annual Meeting. San Francisco, CA: American Geophysical Union.
• Jim, R., Sethuraman, A., & Hoover, J. H. (2023, October). Science Communication of Polycyclic Aromatic Hydrocarbons (PAH) Exposures from Waste & Landfill Burning in an Indigenous Community. American Indian Science Engineering Society Conference. Spokane, WA: American Indian Science Engineering Society.
• Sethuraman, A., Shuey, C., Dixon, E., Tsotie, K., & Hoover, J. H. (2023, December). Establishing a citizen science monitoring program for groundwater quality in a Southwestern US community: an intervention for water resilience and climate adaptation. American Geophysical Union Annual Meeting. San Francisco, CA: American Geophysical Union.
• Woldeyohannes, T., Doyle, J., Girlamo, C., Liu, Z., Sethuraman, A., Eggers, M., Erdei, E., Lin, Y., & Hoover, J. H. (2023, August). Researching Environmental Health Impacts from Unregulated Solid Waste Disposal (USWD) with Native American Communities.. NIH IDeA Western Regional Conference. Santa Ana Pueblo, NM: National Institutes of Health.
• Woldeyohannes, T., Doyle, J., Girlamo, C., Liu, Z., Sethuraman, A., Eggers, M., Erdei, E., Lin, Y., & Hoover, J. H. (2023, December). Researching Environmental Health Impacts from Unregulated Solid Waste Disposal (USWD) with Native American Communities.. Superfund Research Program Annual Grant Recipient Meeting. Albuquerque, NM: National Institute of Environmental Health Science.
• Harvey, D., Lee, A., Exum, N., Schwab, K., Cuddy, R., Barlow, A., Hoover, J. H., Clapp, R., Tulley, N., Lee, W., Tulley-Cordova, C., & Chief, K. (2022, October). Assessing the Challenges to Improve Water Access for Navajo Nation Households Without Piped Drinking Water. Water and Health Conference. Chapel Hill, NC: University of North Carolina.
• Hoover, J. H., Doyle, J., Woldeyohannes, T., Girlamo, C., & Lin, Y. (2022, December). Improving geospatial environmental health research with Tribal communities in Montana and New Mexico. 8th Biennial National IDeA Symposium of Biomedical Research Excellence. Virtual: IDeA program of the National Institute of General Medical Sciences (NIGMS).

Other Teaching Materials

• Yazzie, S., Hoover, J. H., & Van Orneals, Y. H. (2023. Methods, Ethics and Practice to Collaborate with Communities, Session leads for: Data sovereignty and translational science. Indigenous Environmental Health Research Workshop.