If you've ever stood on a beach on the coast of southern San Diego and caught a whiff of something foul that made your nose hairs curl, it wasn't your imagination — and definitely not something the ocean does. Nope, some of that sea breeze is contaminated by the Tijuana River. Wastewater. Chemicals. Even traces of drugs. And while it sounds gross, researchers say it's more than just a bad smell; it may also be hazardous to people's health.

What's happening?

A new study from UC San Diego tracked pollution from the Tijuana River and found it's showing up in the air, not just the water. According to Phys.org, scientists detected sewage pollutants — including industrial runoff and personal care product chemicals — in sea spray aerosol.

Lead author Adam Cooper collected samples across several sites, including Imperial Beach and La Jolla. Among the pollutants found were methamphetamine, benzoylecgonine (a cocaine byproduct), tire chemicals, and octinoxate — a common sunscreen ingredient.

"It's been shown that octinoxate can degrade DNA when exposed to light," said Jonathan Slade. "And if it's in these tiny aerosols we're breathing in, it can get deep into our lungs and pass into our bloodstream. That's very concerning."

Why is this concerning?

Residents near the Tijuana River, especially in Imperial Beach, are breathing these contaminants every day. Some, like cocaine, appear in tiny amounts. Others, like octinoxate, show up in concentrations similar to those inside wastewater treatment plants.

Slade said exposure depends heavily on proximity to the river. And locals have already reported issues like headaches, insomnia, and breathing problems. Some beaches have been shut down for nearly three years due to high bacteria levels.

"Often the sewage crisis is considered a water issue — and it is — but we show that it's in the air too," Slade said.

What can be done about it?

EPA Administrator Lee Zeldin addressed the issue during a recent visit, calling for more than just water treatment — real changes that cut pollution at the source.

"I was just briefed that Mexico is dumping large amounts of raw sewage into the Tijuana River, and it's now seeping into the U.S. This is unacceptable. Mexico MUST honor its commitments to control this pollution and sewage!" Zeldin said in a post on X.

Cooper said the problem isn't technology, it's policy. "The solutions... aren't constrained by technical challenges," he said. "They're constrained by political challenges and policy issues."

When the air, the water, and the people are all getting hit, it's time to treat this like the shared responsibility it is.

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