# RP-Sant/Quintana: Assessment of Exposure to Microbial and Chemical Pollution in US Community Air from the Binational Tijuana River Watershed

> **NIH NIH U54** · SAN DIEGO STATE UNIVERSITY · 2024 · $367,386

## Abstract

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...

## Key facts

- **NIH application ID:** 11002226
- **Project number:** 2U54MD012397-06A1
- **Recipient organization:** SAN DIEGO STATE UNIVERSITY
- **Principal Investigator:** Karilyn Elizabeth Sant
- **Activity code:** U54 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $367,386
- **Award type:** 2
- **Project period:** 2018-09-11 → 2029-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11002226

## Citation

> US National Institutes of Health, RePORTER application 11002226, RP-Sant/Quintana: Assessment of Exposure to Microbial and Chemical Pollution in US Community Air from the Binational Tijuana River Watershed (2U54MD012397-06A1). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/11002226. Licensed CC0.

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