A NASA instrument aboard the International Space Station has detected contamination from Mexican sewage that spilled into the Pacific Ocean off the coast of Southern California.
Why It Matters
The Tijuana River flows from Mexico into California and drains into the Pacific Ocean, transporting millions of gallons of untreated sewage along with it. This long-standing issue has raised alarms over its impact on both public health and the environment.
What To Know
The instrument, known as the Earth Surface Mineral Dust Source Investigation (EMIT), was originally used to map minerals in desert regions but is now offering insights into water quality.
In a recent study, EMIT was able to identify phycocyanin—a pigment found in cyanobacteria—within a massive wastewater plume off the mouth of the Tijuana River.
Cyanobacteria are an organism capable of causing illness in humans and animals through ingestion or inhalation, NASA said.
EMIT operates by analyzing light reflected from Earth’s surface, breaking it down into hundreds of visible and infrared color bands. Each material, including pollutants, has a unique spectral signature that allows scientists to identify it.
Researchers matched EMIT’s satellite data of the Tijuana River plume with results from ground-tested water samples. Both methods identified a spectral signature indicating the presence of phycocyanin.
The findings come as Southern California beaches near the United States-Mexico border have repeatedly faced closures due to contamination. Millions of gallons of wastewater enter the Tijuana River annually, emptying into the ocean and posing a health hazard to swimmers and military personnel stationed in the area.
San Diego County beaches have seen 1,000 days’ worth of closures in recent years, and a report from the Department of Defense’s Office of Inspector General documented 1,100 cases of illness among Navy SEALs and other service members exposed to polluted waters.
What People Are Saying
Christine Lee, a scientist at NASA’s Jet Propulsion Laboratory and a co-author of the study, said: “From orbit you are able to look down and see that a wastewater plume is extending into places you haven’t sampled.
“It’s like a diagnostic at the doctor’s office that tells you, ‘Hey, let’s take a closer look at this.'”
Eva Scrivner, a doctoral student at the University of Connecticut and the study’s lead author, said that the findings “show a ‘smoking gun’ of sorts for wastewater in the Tijuana River plume.”
What Happens Next
Lee Zeldin, the administrator of the Environmental Protection Agency, stated in May that the U.S. International Boundary and Water Commission was expediting an expansion of the South Bay International Wastewater Treatment Plant, which treats sewage and wastewater from Tijuana, by 10 million gallons per day in an effort to mitigate the crisis.
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