It’s More than Just Sewage: 175 Toxic Chemicals Found in Water Samples, Scientist Says

Turns out there’s a lot more than sewage polluting our rivers, oceans and air, according to scientists who study the cross-border sewage crisis.

More than 175 toxic chemicals have been found in water samples collected from the Tijuana River Valley, according to Dr. Paula Stigler Granados, who spoke at the Coronado High School Stop the Sewage Health Forum on Wednesday.

“These chemicals are bad actors,” said Granados. “These are things that should not be in our waters.”

She said that out of the 392 chemicals found in samples, 224 appear on a regulatory list, and 175 appear in the EPA Toxic Substance list. In addition, many of the chemicals are what scientists call an “emerging concern,” which means no one knows just how toxic they are yet.

“When we talk about sewage, we think about pathogens and we think about bacteria,” said Granados. “But there is stuff in the water other than just sewage, and we want to be very clear about it.”

This includes everything from pharmaceutical drugs like anesthetics to illegal drugs like cocaine and meth, according to a list shared at the meeting. That’s in addition to pesticides and chemicals used in manufacturing.

As if the untreated sewage isn’t bad enough.

“It’s sewage, so we’re finding what we’d expect to find,” said Granados. “Antibiotic-resistant genes are in vast amounts of the sewage that’s leaking out.”

But it’s the sheer quantities that worry the scientists.

“You’ve probably heard of salmonella, strep, tuberculosis, listeria, all of this is in the water,” said Granados. “We know we’ve heard from Navy SEALS, we’ve heard from surfers, we’ve heard from people living on our coastline, people do get sick when they get in the water.”

And then there’s the question…do the chemicals affect the air we breathe? According to Granados, you don’t have to come in direct contact with the water to get sick.

According to research from University of California, San Diego, up to 76% of bacteria found in the air in Imperial Beach is directly linked to the sewage in the Tijuana River.

“That study prompted us to think . . . how much of that do people actually breathe in, and get sick from?” asked Granados.

Researchers do know, for example, that hydrogen sulfide levels grossly exceed state thresholds. It’s one of the easiest chemicals to monitor because it’s easy to smell. The “nuisance level” of hydrogen sulfide is about 30 parts per billion, but samples collected from Imperial Beach put it at 300 or 400 parts per billion.

“There are turbulent areas within the river itself that are creating these gas releases,” said Granados. “As that hydrogen sulfide builds up, it hits some of the aerosolization zones or hotspots, and that’s just where the gases are released and they just spread out.”

She says according to surveys and studies, many residents of Imperial Beach wake up and can’t breathe at night. It’s a frequent occurrence for many, and hits the special population with autoimmune disorders really hard.

According to a recent survey of Imperial Beach residents on the effects of the cross-border sewage crisis, 77% suffer from upper respiratory problems and 41% have had diarrhea. 77% of those surveyed have suffered from headaches, and 62% have had trouble sleeping.

Among families with older adults and children, 80% are spending less time outside.

According to Emily Allen, Area Operations Manager of the United States International Boundary and Water Commission (USIBWC), the current infrastructure just isn’t keeping up with the explosive growth in Tijuana population.

Part of the problem is the sediments in the cross-border flow in the Tijuana River.

“One of the biggest issues we have is that a treatment plant doesn’t deal with sediment trash,” said Allen. “Our U.S. treatment plant treats what’s in the sewage system. But the amount of sediment coming across hits the treatment plant and knocks it out.”

In the last few years, she says she’s seen a “humongous” amount of flow in the river, even during dry season, when we wouldn’t expect it. Allen says this flow is responsible for the beach closures and smells, and high levels of hydrogen sulfide in the hot weather.

“We’re still seeing flow in the river, even with the sewage treatment plants online and taking mass capacity,” she said. “That’s the problem that we need to solve.”

She says the IBWC is working on four key fronts: repair and compliance, rehabilitation and expansion, development of key projects on the Mexican side of the border, and accelerated commissioner meetings on transboundary flows.

“We expect to incrementally increase capacity, and increase the way we treat and remove the transboundary flow, little by little,” she said.

According to Congressman Scott Peters, who sent a representative to attend the meeting, there is great reason for hope.

“It’s painfully slow, but the work is underway,” he wrote in a letter read at the meeting. “Thanks to the nonstop advocacy of San Diego’s congressional delegation, including the support of Coronado, San Diego and Imperial Beach officials, we’ve secured $653 million to modernize the South Bay International Water Treatment Plant.”

He said the plant will capture the wastewater flowing from Mexico, treat it to U.S. Clean Water Act standards and discharge it four miles into the ocean.

“It’s not the only solution, but it will play a major role in solving the problem,” he wrote.

Peters also said that, for the first time, earlier this year the Navy acknowledged negative logistical impacts on training operations because of the sewage.

“We’ve heard about Navy SEALS getting sick from training in these waters, but got no official word from the Navy,” he wrote. “But that changed after the San Diego delegation sent a letter requesting specific information on the health impacts.”

Peters wrote that earlier this week, the EPA administrator Lee Zeldin, along with other officials from the Trump Administration, met with Navy SEALS and staff to learn how the water contamination is hurting operations from those who plan and direct those operations.

But he admitted that there are still “dozens” of projects that must be completed, most of them south of the border. And while Zeldin didn’t give any indication of clawing back funds already approved for international wastewater treatment, he said that Mexico needed to hold up its end of the bargain.

“What he did say is that the administration was not inclined to support one penny more from the federal government until Mexico designates funds needed to complete the projects that they agreed to in the treaty with them,” wrote Peters.

He encouraged residents to keep up with their advocacy.

“Your voices matter in this fight,” wrote Peters. “Stay engaged, and keep speaking out together.”