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Hours after a November storm, the Tijuana River flooded a grove of trees in Imperial Beach, gushed through a row of calverts and exploded into mounds of fetid foam.
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This is ground zero for the contaminated river, which sickens thousands of people in southern San Diego County.
“The Tijuana River is one of, if not the most polluted, river in the entire United States,” said San Diego County Supervisor Paloma Aguirre, who viewed the overflowing river wearing black rain boots and a hot pink respirator mask. “The river is carrying dangerous chemicals, pollutants, pathogens and toxic gases that are impacting South San Diego communities.”
The site, known as the Saturn Boulevard hot spot, is part of a system of polluted waterways and failed sewage treatment plants in the cross-border region. In the ocean, the contamination leaves swimmers and surfers with breathing problems, digestive illness and rashes. Unsafe conditions have closed parts of the Imperial Beach shoreline for three years.
Last year, researchers discovered that the pollution is airborne as well. Foul-smelling hydrogen sulfide emissions near the river sometimes rise hundreds of times higher than the state’s odor threshold. At those levels the gas triggers headaches, nausea, eye irritation and respiratory distress. And there are other chemicals, viruses and bacteria in the mix.
For children, the effects are worse, said Tom Csanadi, an Imperial Beach physician who has been active in the issue. Their lung surface area to body size is higher, which means they absorb more toxins. Children breathe faster than adults and they’re still growing, so it can affect their body tissues more severely. There are 11 schools within three kilometers of the hot spot.
“It could lower IQ, stunt cognitive development,” Csanadi said.
As a surfer, activist and elected leader, Aguirre has spent two decades tackling this problem, which she considers one of the worst environmental crises in the country.
















