(The Center Square) – The Tijuana River sewage crisis continues to grow as a new study shows pollutants in the wastewater are degrading air quality in San Diego.
A study from the University of California San Diego published in Science Advances May 28, shows the presence of pollutants in the air and water along the coast of San Diego. The study raises health concerns among San Diegans as millions of gallons of wastewater continue to flow every day across the U.S.-Mexico border into the Pacific Ocean from the Tijuana River.
“Oftentimes we think of pollution as in only going into the ocean and affecting marine life, but we show from our study that pollution can be airborne and affect people on the coast,” Adam Cooper, the paper’s lead author, told The Center Square.
The study looked at samples Cooper collected in 2020 from the water and air at various points along the coast such as the U.S.-Mexico Border, Imperial Beach and the Scripps Institution of Oceanography in La Jolla.
Assistant Professor of Chemistry and Biochemistry Jonathan Slade’s lab then looked at the samples, first searching for a chemical the lab knew came from sewage – benzoylecgonine or BZG – which is produced when people take cocaine and urinate. Researchers found that the BZG levels in Imperial Beach ocean water rose after rainfall, and BZG levels in the air in Imperial Beach rose when there was an increase in sea spray aerosol emissions, according to UC San Diego.
Slade’s lab then looked at other pollutants and discovered that other chemicals act in a similar way as BZG including methamphetamine; octinoxate, a UV filter used in sunscreen; and dibenzylamine, a compound used in car manufacturing, according to NBC 7 San Diego.
Low amounts of methamphetamine and dibenzylamine were found, but significant levels of octinoxate were found.
“When octinoxate is exposed to sunlight, it can degrade into a more toxic photoproduct,” Slade told The Center Square Monday. “This photoproduct has been known to lead to DNA damage.”
Although the samples were taken several years ago, Cooper and Slade said they believe the information in the study is still relevant today because the population in the Tijuana area is increasing, and large amounts of water continue to flow into the U.S. from the Tijuana River.
“We haven’t made any recent measurements of it so we can’t say for sure, but there hasn’t been any large-scale changes in how the issue has been treated, so it’s effectively the same,” Slade said. “Potentially worse, because there’s more people. So as the urban population grows, it is likely that there is more stuff getting into the environment.”
Mike Bastasch, spokesperson for the Environmental Protection Agency, said the pollution has been a long going issue, but noted President Donald Trump and Mexican President Claudia Sheinbaum Pardo have given the EPA immense support in solving it. Bastasch also said the EPA and the U.S. and Mexico section of the International Boundary and Water Commission announced on May 20 plans to accelerate the expansion of the South Bay International Wastewater Treatment Plan from 25 gallons to 35 gallons in 100 days, instead of the original plan of two years.
“We’re committed to a 100% solution that permanently ends the decades-long Tijuana sewage crisis,” Bastasch said in a statement to The Center Square. “This is a public health and national security imperative.”
Slade said more research groups are working to better understand the severity of the Tijuana River sewage problem such as co-author of the UC San Diego research paper Kimberly Prather’s research group. Slade also said Prather has made some new discoveries.
“They are collecting air samples at the Tijuana River itself and are seeing high levels of other pollutants coming directly from the river,” Slade said. “That is a new seeing because we had thought previously that this was only happening at the coast where there were crashing waves. But I guess you can have it directly in the river where there is turbulence.”
Slade said he hopes that from the research being done and the growing awareness of the Tijuana River sewage crisis, people can become more aware of their waste output.
“It is important to realize that what we waste, that waste can be put back into the air. And we can be exposed to it in ways we never thought before,” Slade said.
