RESEARCH PROJECT - SANT/QUINTANA - Project Summary This project investigates exposures and potential health effects in communities disproportionately burdened by environmental exposures near the US-Mexico border, and the potential to mitigate these risks on children’s health through a home-based intervention. The Tijuana River is a binational watershed flowing from Tijuana, Baja California, Mexico north into the US near the communities of San Ysidro and Imperial Beach, CA. This watershed is highly impaired, due to high volumes of sewage, industrial waste and runoff that enter the river and estuary. In our Center-funded Pilot Project, a 2-year spatiotemporal field survey of water within the Tijuana River and Estuary, we applied state-of-the-art non-targeted chemical analysis and metagenomics to characterize a broad suite of contaminants. We discovered that microbes with antibiotic-resistant genes, a public health concern, were highly elevated in the Tijuana River in sites near the waste flows relative to more distant sites. Persistent and toxic chemicals associated with untreated sewage and industrial waste were highly concentrated in the near-border sites. This impaired water also poses a potential threat to air quality in the community. Unlike water, air can diffuse across the community and enter homes, childcare centers, and schools, and expose community members who are not contacting the water source. In addition, while long- range transport of persistent chemicals transferring from water to air is a well-known cause of global chemical contamination, transfer to air in communities near impaired water bodies has not been explored from an environmental justice lens. In Aim 1, we will use cutting-edge non-targeted methods to assess microbial and chemical constituents of community air samples in relation to proximity to the Tijuana River, especially antibiotic resistance genes. In Aim 2, we will examine chemical and microbial signatures of Tijuana River source pollution identified in Aim 1 in community air and inside of homes, including detection of antibiotic resistance genes within household dust, in relation to child microbiome, assessed via hand, oral, and fecal swabs. In Aim 3, we will inform the development of a home-based intervention with Casa Familiar, a community-based organization with a long-history of environmental justice work. Together, we will use well- established and innovative formative research methods and Intervention Mapping to identify determinants and change strategies important for mitigating environmental risks, with a specific emphasis on reducing barriers to implementation of prevention and control measures. Overall, we aim to apply these high-throughput, state-of- the-art environmental science laboratory methods to a border health framework and using an environmental justice lens. The methodologies developed and used in this Research Project can be broadly applied to environmental justice communities experiencing unequ...