Claudia Nguyen

Project title: Characterization of Children’s Arsenic Exposure Using Urinary Metabolites

Degree: MS (Applied) | Program: Applied Toxicology (App Tox) | Project type: Project
Completed in: 2021 | Faculty advisor: Elaine M. Faustman


Arsenic is a long-lasting environmental contaminant found in food, water, air, and soil. In Washington, there are multiple geographically unique sources of arsenic ranging from natural sources like sediments and groundwater to man-made sources. Areas surrounding historically operated copper smelters in the Seattle area and lead-arsenate contaminated crop and orchard lands in Yakima could pose a potential health hazard to children due to the potential for arsenic exposure. The aim of this case report is to characterize arsenic exposure in 368 children using urinary arsenic species data from the Washingtonbased Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) cohort. Urinary concentrations of inorganic arsenic (iAs) and its metabolites methylarsonic acid (MMA) and dimethylarsinic acid (DMA) were measured using HPLC-ICP-MS from spot urine samples collected at study site visits between July 2017 and June 2020. Methylation efficiency was evaluated using urinary concentrations (ng/mL, noncreatine corrected) of arsenic metabolites. The impact of factors such as study site location (Seattle or Yakima), race and ethnicity, child sex,and maternal income were evaluated. There was no statistically significant difference in the concentration of urinary arsenic species based on child sex, maternal income, or race and ethnicity. There were some statistically significant (p< 0.05) differences in As(III), iAs, %iAs, %DMA, and primary methylation index (PMI) between study sites. The average concentration of iAs, MMA, and DMA for the cohort was 0.60 ng/mL, 0.54 ng/mL, and 5.24 ng/mL respectively. DMA made up the largest portion of urinary arsenic species. The PMI and secondary methylation index (SMI) for the cohort was 0.88 and 0.89 respectively. There are many factors such as immediate environment and nutritional status that can influence arsenic exposure and metabolism warranting further research.