University of Arizona
Norma Villagómez-Márquez is a Ph.D. Candidate in Soil Water Science at the University of Arizona. Norma has an M.S. in Chemical and Environmental Engineering and is the recipient of a 2018 Carson Haury Scholars Program Scholarship, given to diverse graduate students who are studying renewable energy, environment, and social justice. She was selected as a 2018 Singapore UNLEASH Innovation Lab Talent by the UN to participate in the development of solutions for Sustainable Development Goal # 6 Clean Water & Sanitation. Norma is a 2019 recipient of the Climate Assessment for the Southwest (CLIMAS) Climate & Society Graduate Fellows Program.
Emerging Contaminants in Roof-Harvested Rainwater Collected in Rural and Urban Communities in Arizona
Today, about 40% of the global population lives in arid and semi-arid environments. In these geographic areas water scarcity concerns are common. Harvesting rain has been used as a water conservation measure, particularly where other water resources are scarce. As water scarcity increases steadily, interest in alternative methods to conserve and collect water also rise. Roof-harvested rainwater is one possible alternative to address the global issue. In arid climates like the Sonoran Desert, rainwater can provide a vital component of water resources. National water quality standards for both potable and non-potable domestic usages are thus far undetermined as roof-harvested rainwater is a developing practice worldwide. This project is a citizen scientist driven program that teaches communities across the state of Arizona the scientific method. Over the course of three years, participants will collect roof-harvested rainwater samples and send them to be analyzed for bacteria, organic and inorganic contaminants at University of Arizona by our team of scientists. This poster will cover the organic chemistry aspect of this project only; including sample preparation, analytical method development, and preliminary results. The objective of this study is to fortify informal science learning in underserved communities and help generate water quality guidelines and recommendations for non-potable roof-harvested rainwater domestic use. We aim to investigate the presence of thirty target analyte chemicals in roof-harvested rainwater by applying high-resolution liquid chromatography-tandem mass spectrometry (HR-LC-MS/MS). Roof-harvested rainwater samples were preconcentrated using solid phase extraction (SPE) in preparation for analysis. Chromatographic separations were achieved using a Phenomenex Kinetex (150 x 2.1 mm, 2.6 ?m C18 100 Å) maintained at a constant temperature of 25 °C. The mass spectrometer was operated in positive or negative mode, the spray voltage was 4.0 kV in both modes, and the temperature of the heated capillary was set at 250 °C. Nitrogen was used as the nebulizer and auxiliary gas. Parallel reaction monitoring (PRM) experiments were conducted for pentachlorophenol, glyphosate, nonylphenol, perfluorooctanesulfonic acid, perfluorooctanoic acid, and 2,4-dichlorophenoxyacetic acid, chlorpyrifos, prometon, atrazine, and simazine. Results of the first year of this study confirm detection of nonylphenol and perfluorooctanoic acid in roof-harvested rainwater samples in four Arizona communities: Dewey-Humboldt, Hayden-Winkelman, Globe-Miami and Tucson during all sampling periods in 2018. Prometon was detected in roof-harvested rainwater samples only in the urban community of Tucson during all sampling periods of the same year. Simazine, 2,4- dichlorophenoxyacetic acid and chlorpyrifos were not detected in roof-harvested rainwater samples in the communities of Dewey-Humboldt and Hayden-Winkelman. Atrazine was consistently not detected in roof-harvested rainwater samples in the community of Dewey-Humboldt during all sampling periods. Similarly, simazine was not detected in Globe-Miami roof-harvested rainwater samples and chlorpyrifos was not detected in Tucson roof-harvested rainwater samples during all sampling periods in 2018.