Amid a week-long heat wave, air quality conditions for communities dealing with the ongoing Tijuana sewage crisis worsened as a group studying air pollution in the Tijuana River Valley found high levels of toxic gases in south San Diego communities.
After a research team led by professors from San Diego State University and UC San Diego announced there were high levels of hydrogen sulfide and hydrogen cyanide in the Tijuana River Valley air, the county’s Public Health Department got different results in follow-up sampling and announced there is “not an imminent threat.”
This conclusion comes after local researchers were pulled out of the area due to unsafe conditions, as reported by the San Diego Union Tribune.
“The air quality from harmful pollutants in the Tijuana River is causing a public health crisis in our region with the current heatwave only exacerbating the health threats,” said Dr. Paula Granados, leading researcher from SDSU’s School of Public Health, in a statement on Sept. 8. “There have been multiple reports from community members of headaches, respiratory symptoms, and nausea as well as the unbearable stench from the toxic gases, which include hydrogen sulfide and VOCs, (or volatile organic compounds originating from certain solids or liquids emitted as gases) especially in the nighttime hours.”
In a press conference on Sept. 12, Granados and Kimberly Prather, professor of atmospheric chemistry at UC San Diego and Scripps Institution of Oceanography, announced that they stand by the data they collected and remain committed to helping the community.
“We welcome collaboration from all of our partners,” Granados told The Coronado News.
Urgent requests
The Tijuana River Pollution Task Force includes representatives from: the City of Imperial Beach and Coronado; San Diego State University School of Public Health; Scripps Institution of Oceanography at UCSD.
In a written statement, Prather said the task force has “brought together top scientists in a major field project in the South Bay area to study how the Tijuana River’s poor water quality is degrading air quality, leading to persistent odors and health issues.”
Members of the task force said preliminary findings combined with alarming spikes in respiratory illnesses prove that persistent toxic gases are a significant public health threat.
“Our families, children, seniors and the immunocompromised are constantly at risk, breathing in harmful toxic gases that no one should have to endure,” said Imperial Beach Mayor Paloma Aguirre in a statement. “We are fighting not just for our health but for our right to clean air and a safe environment.”
On Sept. 8, the task force urged the San Diego County Board of Supervisors, the Air Pollution Control District, and the California Department of Public Health to intervene for the health and safety of local residents.
The group asked local agencies to distribute appropriate air filters and purifiers to all residents, especially immunocompromised, elderly, and families with young children. It also asked that they ensure the health and wellbeing of impacted students, teachers and staff at local schools. Finally, it requested installation of instruments for accurate particle and gas monitoring, and placement of advisory signs across the Tijuana River Valley to caution recreationists of toxic gas exposure.
A data graph by the researchers shows hydrogen sulfide counts surpassed standard levels significantly between midnight and the early morning hours of Sept. 3-4.
This discovery brought in an out-of-state hazmat drone specialist team to limit the exposure of researchers, Aguirre told Fox 5 San Diego, and their sensor equipment detected hydrogen cyanide during field work.
Later that week, the San Diego Union-Tribune reported that researchers were pulled out of those areas, which according to Aguirre, meant they were asked to spend the night elsewhere.
On Tuesday, Sept. 10, San Diego County health officials said air quality in the Tijuana River Valley does not pose a public health threat at this time and asserted there is no immediate threat from hydrogen cyanide and hydrogen sulfide levels.
At a press conference, Interim Public Health Officer Ankita Kadakia said the Centers for Disease Control and Prevention will soon perform a comprehensive community health assessment.
Nora Vargas, chairwoman of the Board of Supervisors, said, “I want to reassure everyone that this is not an imminent threat, and it’s safe to be outside and attend school. …It’s unacceptable that south county residents have to worry about whether it’s safe to go outside. I’m fighting every day to address the root of this issue, but for now, you can trust the data — we’ve got your back.”
Concerning air and water
Elizabeth Cardoza, an Imperial Beach resident, told The Coronado News that her family has avoided the ocean for the past five years and they experience sickness all the time. She said she believes a headache all last week “was due to the poisonous gasses.”
“Poisonous gasses were detected in our air as well and our kids’ school sent us a message saying they will be kept indoor because of it,” wrote Cardoza in an email. “The smell lasts all day but it gets worse at night. We don’t have AC in our home so we’re forced to keep the windows open.”
Cardoza added that she couldn’t enroll her kids to play at the IB little league this year for fear of them getting sick being so close to the river.
On Sept. 9, a delegation of San Diego congressional representatives reiterated their request to Gov. Gavin Newsom and President Biden about proclaiming a federal state of emergency in a letter highlighting the “noxious gases” reported by researchers.
Last week, state leaders introduced a bill, the Border Water Quality Restoration and Protection Act of 2024, which would designate the Environmental Protection Agency (EPA) as the lead agency to manage projects to combat the ongoing Tijuana River transboundary sewage pollution crisis.
Earlier that week, Aguirre wrote a letter to Newsom asking him to join the California Legislature in asking Biden for a national emergency declaration, as the more than 60 million gallons of sewage flowing into the ocean daily have led to 1,000 consecutive days of beach closures as of Sept. 7, she said.
“While we recognize the recent declaration of a state of emergency in Rancho Palos Verdes to assist 300 affluent residents affected by shifting land, it is deeply frustrating that a similar level of urgency has not been applied to the ongoing sewage crisis in the Tijuana River, which impacts the health and safety of 750,000 people in south San Diego County,” reads the letter.
Aguirre also asked Mexico’s president, Andrés Manuel Lopez Obrador, for his support in redirecting flows in the Tijuana River to be treated and mitigated before entering the U.S., through the use of wastewater treatment plant Arturo Herrera or La Morita as well as activating an additional pumping station.
Morgan Rogers, Area Operations Manager for the U.S. International Boundary and Water Commission’s South Bay International Wastewater Treatment Plant, announced that repairs have been completed on a key Mexican pipeline.
“Pump station PBCILA has been returned to operation with two pumps online and again diverting flows in the Tijuana River to pump station PB1,” wrote Rogers in an email. “The flows to PB1 are then pumped to San Antonio de los Buenos for ocean discharge south of Tijuana.
According to Rogers, flow in the river dropped from 42 million gallons daily on Sept. 9 to 11 million on Sept. 10.
On Sept. 11, the agency reported that transboundary flows in the Tijuana River had stopped.
Prather’s team announced that levels of hydrogen sulfide during this pause dropped significantly below 100 parts per billion.
The following day Rogers said PBCILA will operate two pumps from 10 p.m. to 1 a.m, during typical evening river peak flows, as the agency is striving for no transboundary flows.
“Our data show high pollution levels that validate residents’ concerns,” Prather said. “Just as we filter water, we must filter the air inside our homes to provide short-term relief while long-term solutions are developed.”
Last month, the county distributed free air purifiers as part of a pilot program approved earlier this year that allocated $100,000 for purifiers to a selected number of homes.
“Four hundred air filters distributed via lottery for approximately 30,000 homes, is not enough,” said Aguirre in the release.
According to Vargas’s office, she will advocate for increased funding and resources from the EPA to expand the distribution of air purifiers to residents affected by pollution odors.
Study still underway
The primary study objective on cross-border water sewage pollution and its impact on air quality is to investigate poor water and air quality in the southern San Diego region and learn its effect on public health, according to the UC San Diego researchers’ project website.
Academics from UC San Diego are collaborating with UT Austin, San Diego State University, UC Riverside, University of Trieste, National Oceanic and Atmospheric Administration, and National Center for Atmospheric Research, reads the online page.
Lauren Fimbres Wood, Director of Strategic Communications at Scripps Institution of Oceanography at UC San Diego, said current field work advances previous studies from Prather’s lab in March 2023 that found “coastal water pollution transfers to the atmosphere in sea spray aerosol, which can reach people beyond just beachgoers, surfers, and swimmers.”
Councilmembers from La Mesa, National City and Imperial Beach stood side by side with Granados and Prather as they called for additional mitigation measures during a Sept. 12 press conference on Hollister Street, at a study “hotspot.”
“I saw the monitors myself, “ said Councilmember Marcus Bush from National City, who sits on the San Diego County Air Pollution Control District. “It’s not safe… My throat started burning after thirty minutes.”
“It is a local emergency,” added La Mesa Councilmember Jack Shu, who is also a board member for the Pollution Control District. “But we need it to be a state and national emergency because when that happens you get other resources.”
