TOXIC CHEMICALS FROM THE TIJUANA RIVER CONTAMINATE SAN DIEGO'S AIR, SAYS NEW STUDY

Vicente Calderón Tijuana Press - With permission

A study conducted by the University of California, San Diego claims to have found evidence of something that has long been suspected and sparked controversy along the border:

That the pollution carried by the Tijuana River affects the air breathed in San Diego.

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The research published in the scientific journal Science Advances states that the current carries a mixture of wastewater, including sewage and industrial waste, in which chemicals such as methamphetamine, traces of cocaine components, and ingredients used in tire manufacturing and sunscreen were detected.

When the river flows into the ocean, it triggers a reaction that spreads the contamination from the water into the air.

“We found that these wastewater compounds become aerosols and are detectable in both water and air,” says the report released this week.

It explains that samples taken in the Tijuana River Valley, Imperial Beach, and La Jolla beaches show that when waves crash against the polluted shoreline, they release a cocktail of hazardous chemicals into the atmosphere.

“Local populations are potentially exposed to tens of nanograms per hour through inhalation,” the study's conclusions add.

The research team, led by Adam Cooper of the Department of Chemistry and Biochemistry at the aforementioned University of San Diego, used an innovative approach, tracking benzoylecgonine—a cocaine metabolite found in human urine—as a wastewater marker. This allowed them to definitively link airborne pollutants to wastewater sources crossing the border.

Chemical concentrations in both air and water samples were highest near the Tijuana River, gradually decreasing as they moved north. The pattern clearly shows the river as the primary source of cross-border pollution, the report says.

 “After rainfall events, we found a correlation between aerosol concentrations and sea spray production,” the scientists explain. As polluted ocean water churns in the surf zone, the formation of bubbles propels pollutants skyward.

Among the most troubling findings is that residents near Imperial Beach are inhaling approximately ten times more octinoxate—a sunscreen chemical—compared to areas farther north. Exposure to methamphetamine through breathing was also significantly elevated.

The study authors acknowledge that further research is needed to understand the true health impacts of these types of pollutants in the air, but their work indicates real impacts even without direct contact with the polluted waters from the Mexican side.

This article was written with the assistance of Artificial Intelligence platforms.