Perfluorinated carboxylic acids (PFCAs) such as perfluorooctanic acid (PFOA), perfluoronanoic acid (PFNA), and perfluorodecanoic acid (PFDA) are worldwide environmental pollutants that are used in many consumer products due to their thermal and chemical stability. They are commonly found in products that resist sticking, water, stains, and grease (e.g. stain-resistant carpet, fire-proof products, paper, and cardboard packaging). The goal of the study was to determine how these PFCA compounds regulate the hepatic transcriptome and especially transporters that are involved in the absorption, disposition, and excretion of drugs, environmental toxicants, and endogenous nutrients. Fully differentiated human liver-cancer-derived HepaRG cells were incubated with 45 μM in the following PFCAs: PFOA (perfluorooctanoic acid), PFNA (perfluorononanoic acid), and PFDA (perfluorodecanoic acid) for 24 hours. The advantage of using HepaRG cells as compared to other common immortalized human hepatocyte cell lines is that HepaRG cells retain more characteristics of human livers and express most drug-metabolizing enzymes, thus serving as an excellent tool to recapitulate toxicological responses in vivo where the research is done within the organism. Total RNA was isolated from vehicle and PFCA-treated HepaRG cells (n=3 per group) and was subjected to RNA sequencing. Pathway analysis showed that PFCAs with increasing carbon chain lengths up-regulated the mRNAs of many amino acid transporters, which are essential for protein synthesis. PFCA compounds with longer carbon chain lengths also down-regulated several uptake transporters for xenobiotics and bile acids, but up-regulated several efflux transporters - likely as a compensatory mechanism to limit further toxic exposures and pump out toxic substances, respectively. Overall, our study is significant because the regulatory responses may function as biomarkers of PFCA exposures in the liver even at low doses; this can help prevent liver injury such as inflammation and possibly liver cancer.

The gut microbiota, or the microorganisms that live in the gastrointestinal tract (GI), play a significant role in both gut and overall health. In LMICs (Low-Middle Income Countries), diarrheal diseases are among the leading causes of death in children under five. The ongoing EcoMiD (Enteropatógenos, Crecimiento, Microbioma, y Diarrea) project aims to study the interaction between infants' gut microbiomes and viral, bacterial, and parasitic enteric pathogens along a rural-urban gradient in Ecuador through a cohort study of 600 mother-child dyads. The objective of this portion of the study was to validate a method for assaying multiple enteric pathogens in stool samples simultaneously using TaqMan Array Cards (TAC). Before samples can be analyzed using TAC, each of the 56 pathogenic targets of interest must be validated to determine the limit of detection, limit of quantification, inhibition effect of the stool matrix on detection, repeatability and reproducibility. The TAC Positive Control validation process initially involves growing up each of the organisms of interest, extracting its' total nucleic acids (TNA) and quantifying this through (RT)-qPCR and Qubit. Analysis of this data enables seeding the positive controls at known concentrations to quantify target TNA for TAC. Of the 56 targets, we have completed this work with 35 targets (26 reference organisms, 9 gBlocks). For targets that are time/cost intensive to work with or not culturable, gBlocks are utilized in place of reference organisms. gBlocks are synthetic gene fragments with a known sequence. Next steps of this process includes validation of the 21 remaining pathogens, some of which involves working with anaerobic organisms. Analysis of this data will inform seeding concentrations to validate the developed TAC and enable quantification of these targets in stool samples from Ecuador. 

Global climate change is here and it is already affecting exposure to heat across Washington state. Heat exposure can exacerbate climate-sensitive health threats by increasing risks for groups who are more susceptible--particularly in non-acclimatized areas. The World Health Organization has predicted that diabetes will be the 7th leading cause of death by 2030. It is critical to define the interactions between heat and diabetes to prevent excess risk; having diabetes leads to reduced thermoregulation (body's ability to regulate heat) which affects other organs critical for sustaining life. My research focuses on the intersection of health impacts of heat on people with diabetes and how these relationships change with increasing temperatures. It also considers how mitigation and adaptation can protect the 1 in 8 people in Washington who have diabetes as part of the overall goal of managing the health risks of climate change. I consider the relationship between heat and diabetes by performing a literature review of peer-reviewed, original research in different academic journals. Then, outcomes are compared and synthesized to determine if there is a causal relationship where temperature affects the odds of diabetes morbidity and mortality. My research found that those who have diabetes have higher odds of negative health outcomes and death as temperatures increase. Through a variety of mitigation and adaptation strategies, we can reduce the odds of and prevent excess morbidity and mortality. Taking this research into account, Washington can be more conscious in its public health interventions during periods of increased heat to prevent excess diabetes-related morbidity and mortality. More research is needed on the effectiveness of specific interventions for Washington on reducing the odds of morbidity and mortality for people with diabetes.

Understanding the human health effects from marine plastics is an emerging field of public health. Marine plastic waste contributes to a global plastic problem. Evaluating health impacts from marine litter requires approaches that characterize plastics as well as health perceptions from different populations. This project contains two parts: 1) a focused review of nanoplastic methodologies to frame how standardization is needed to compare findings across studies and measure health effects and 2) a household survey to understand how marine plastics impact well-being in two coastal communities in Ghana. The meta-analysis on nanoplastic techniques showed a variety of techniques are used, among which the most common are Raman spectroscopy and Pyrolysis Gas Chromatography Mass Spectrometry. Different definitions of nanoplastics were identified across studies, where “nanoplastic” was most commonly defined as a plastic polymer with a diameter less than 1000 nanometers. The meta-analysis also showed that many studies analyzed spherical polystyrene because they are easy to obtain rather than other plastic polymers that are representative of environmental exposure. The Ghana survey included a quantitative analysis of demographics, plastic dependency, stress, well-being, and perceptions on plastic waste management. The majority (72%) of Ghana survey respondents were of low socioeconomic status (making less than 355 Ghanaian Cedi a month (~54 United States Dollars) during the pandemic). Many respondents agreed that plastics have improved their quality of life but expressed concern about plastics effects on their health and livelihood. As the field of marine plastics develops, robust standardized techniques must be adopted and real world nanoplastic samples need to be included in studies. Considerations of equity and health outcomes should be in place as well. Understanding how different populations, especially underserved and marginalized communities, perceive and use plastics is instrumental for solving this global plastic problem.

Farmworkers often experience substandard housing conditions, including crowding, temperature and humidity variability, and limited cooling access. We investigated how in-home temperature, humidity, bedroom crowding, and cooling impacted sleep duration among Washington State (WA) farmworkers. We hypothesized that elevated sleep temperatures, humidity, and crowding would be associated with reduced sleep duration. In the summer of 2019, 81 orchard and vineyard workers in Central WA participated in a baseline housing characteristic survey, three successive monthly sleep surveys, and three sleep temperature measurements. We assessed housing quality, our exposure of interest, defined as: housing type, air conditioning (AC) availability, crowding (> 2 adults in bedroom) and sleeping room temperature and humidity measured with Kestrel Drops. Our outcome measure was self-reported sleep hours per night. On average, participants were 42 years of age, male (64%), had 3.4 years of agriculture experience, and slept 6.5 hours per night at 76°F and 50% humidity. 45% lived in single-family homes, 11% in apartments, 28% in barracks, and 16% in mobile homes. Average temperature did not differ between housing types. Maximum temperature was greatest in barracks (average max=83.3°F) and apartments (85.0°F) versus single-family homes (79.7°F) and mobile homes (80.1°F). Relative humidity was highest in barracks (55.5%) versus single-family homes (48.9%), mobile homes (44.9%), and apartments (45.7%). Crowding and access to AC also varied with housing type, with 100% of barracks participants and 14% of mobile home participants reporting overcrowding, and apartment participants (100%) and barracks participants (97%) being the most likely to report AC. Participants in barracks reported less sleep per night than participants in single-family or mobile homes (6 versus 7 hours, respectively). We found variation in farmworker housing conditions and reduced sleep duration in barracks. We recommend future research examining the role of housing and workplace characteristics on worker sleep quality.

Long term exposure to air pollution can be detrimental to health, leading to respiratory effects, cardiovascular effects, and total mortality. In the 1930s, a practice called redlining reduced the accessibility of mortgage financing for racial minorities and immigrants, and continues to affect the infrastructure and demographics of neighborhoods today. Understanding characteristics of air pollutants is important because people of color and low income communities have historically been exposed to higher concentrations of air pollution as a result of discriminatory practices. Communities exposed to high levels of multiple pollutants at once may be more at risk for health effects. In this project I aimed to define pollutant mixtures of black carbon (BC), nitrogen dioxide (NO₂), carbon dioxide (CO₂), and ultrafine particles (UFPs) at measured locations in Seattle, then predicted the mixtures at other locations to evaluate exposure disparities due to redlining. Annual average air pollution estimates for BC, NO₂, CO₂, and UFPs were obtained from mobile monitoring measurements of 309 residential locations throughout urban Seattle in 2019 and 2020. Distances to roadways, airports, and other pollution sources were obtained using GIS software, and land use, population density, and greenspace were also characterized. Initial pollutant mixtures were defined at the mobile monitoring locations using principal component analysis. The first PC is a weighted average of pollutants, representing the contrast between high and low exposure locations, and the second PC is a contrast between UFPs and other pollutants. I then predicted the mixtures in redlined neighborhoods using geographic covariates. These predictions provide insight into how the patterns of UFP exposure differ from other pollutants, giving us a better understanding of the pollutant mixtures in our community as a result of urban planning. These insights can lead to further research on the toxicity of these mixtures and to equitably work toward cleaner air.

The ‘Pesticides Labels Now!’ mobile application strives to minimize agricultural worker and community exposure and illness from agricultural pesticides through improving access to pesticide labels and safety information in Spanish and English. Pesticide handlers, managers, and supervisors are able to gain access to this information, change behaviors accordingly, and transfer the safety information to others. We hypothesized that user characteristics such as language choice, mobile device type, and location would determine frequency of interactions with the application. This study investigates the application’s user audience and their preferences for app utility. Statistical analysis and graphing was conducted with R Studio (Version 2021.09.1) for users accessing the application over one year starting in August 2020. The raw data set consisted primarily of users from the State of Washington, containing 67,754 interactions and a total of 503 unique users. The results showed that user utilization is predominantly concentrated in central Washington, which is part of the Columbia Basin, and has very productive agricultural land. The overall frequency of each language accessed on the application was relatively comparable - with 59% in English and 41% in Spanish. The analysis further indicated the majority of users utilize the application through an iOS system. An estimated 74% of interactions were accessed through an iPhone device and 26% were accessed through an Android device. By understanding the effect of user characteristics in their interaction with the application, necessary adjustments can be made to the application to create a more user-friendly experience and contribute to improving access to pesticide labels and their safety information.

Individuals experiencing homelessness and housing instability in King County have inadequate access to water, sanitation, and hygiene (WASH) services. This urgent matter of community health has only been exacerbated by the coronavirus disease (COVID-19) pandemic in recent years and can necessitate open defecation or unsafe disposal of wastewater. Particularly among those residing in recreational vehicles (RVs) and use their bathroom facilities, unsafe sanitation practices increase the risks of intestinal pathogen transmission and infection in densely populated communities. In a continuation of efforts to address this, I have developed a study that aims to identify an optimal method of RV wastewater concentration for downstream detection of pathogens. With informed consent from RV residents and sampling assistance from Seattle Public Utilities, I have began collecting a representative collection of samples of RV wastewater from multiple neighborhoods across Seattle. I have utilized a split-and-seed approach in which half the samples were seeded with known amounts of target bacterial, viral, and spore-forming organisms, and the other half left unseeded as a control. These samples will be used to compare two methods of sample concentration, skimmed milk flocculation and membrane filtration, using a weighted rubric that evaluates biosafety, seeded organism recovery efficiency, personnel time, and cost. Upon observation in the lab, I have found that skimmed milk flocculation led to inhibition during detection via molecular assays. Additionally, high turbidity of the samples yielded significant logistical challenges with processing skimmed milk samples, leading my team and I to instead favor the membrane filtration technique. As we move forward, I anticipate detecting elevated levels of pathogens in wastewater from RVs when compared to samples from control locations chosen to represent populations living in sewered and unsewered environments representing populations. Upon development of the optimized protocol, my work will be prepared for publication in a peer-reviewed journal and shared with the City of Seattle.