A recent study revealed that NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) was able to detect signs of sewage in the water near a Southern California Beach.
The study examined a large wastewater plume at the mouth of the Tijuana River, south of Imperial Beach near San Diego.
Satellites have long-tracked water quality issues like harmful algal blooms, but other pollutants and bacteria are more difficult to monitor because they are harder to distinguish with traditional satellite sensors, according to NASA.
EMIT was built at NASA’s Jet Propulsion Laboratory (JPL) to map minerals on earth. The hyperspectral instrument orbits Earth aboard the International Space Station where it observes sunlight reflecting off the planet's surface. It has advanced optical components that split the visible and infrared wavelengths into hundreds of color bands.
Scientists can analyze each satellite scene to discern what molecules are present based on their unique spectral “fingerprint,” according to NASA.
Scientists compared the observations from EMIT with water sampled from the Tijuana River. Both detected phycocyanin, a pigment in cyanobacteria – an organism that can sicken humans and animals if ingested or inhaled.
“From orbit you are able to look down and see that wastewater plume is extending into places you haven’t samples,” said Christine Lee, scientist at JPL in Southern California and coauthor of the study, in a JPL news article. “It’s like a diagnostic at the doctor’s office that tells you, ‘Hey, let’s take a closer look at this.’”
Doctoral student at the University of Connecticut, and lead author of the study, Eva Scrivner noted that EMIT could be useful for filling data gaps where traditional water sampling takes a lot of time and money.
The full study can be found here.
