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New Study Traces Airborne Dust Back To Shrinking Salton Sea

A bird skirts the Salton Sea's receding shoreline, April 10, 2015.
Nicholas McVicker
A bird skirts the Salton Sea's receding shoreline, April 10, 2015.
New Study Traces Airborne Dust Back To Shrinking Salton Sea
New Study Traces Airborne Dust Back To Shrinking Salton Sea GUEST:David Wagner, science and technology reporter, KPBS

OUR TOP STORY, WHEN IT COMES TO THE SALTON SEA, MOST OF WHAT WE HEAR IS GRIM PREDICTIONS OF WHAT WILL HAPPEN IF CALIFORNIA'S LARGEST LAKE IS ALLOWED TO EVAPORATE. A STUDY SAYS THE PREDICTIONS HAVE ALREADY STARTED HAPPENING. SECTIONS OF THE SALTON SEA THAT HAVE ALREADY DRIED UP, ARE CREATING MORE DUST AND HEALTH RISKS. JOINING ME AS DOSH IS DAVID WAGNER. -- IS DAVID WAGNER. WHAT DO WE LEARN THAT IS NEW IN THE STUDY?BASICALLY THE STUDY COMES ALONG AND CONFIRMS ONE CONCERN THAT PEOPLE HAVE HAD ABOUT IT DRYING UP. IT ALSO PROVIDES SOME PRELIMINARY GOOD NEWS ABOUT A DIFFERENT CONCERN. THE RESEARCHERS WHO LED THE STUDY SAY THIS IS THE FIRST STUDY TO LOOK AT, AIRBORNE PARTICLES AND TRACE IT BACK TO WHERE IT IS COMING FROM. IS IT COMING FROM A NEWLY EXPOSED LAKEBED OR FROM THE DESERT AS IT NORMALLY WOULD. THEY SAY IT IS THE FIRST STUDY TO LOOK AT THE CHEMICAL COMPOSITION OF THE NEW DUST, WHAT IS IN IT, IS A DIFFERENT, THE BAD NEWS FIRST. THE STUDY CONFIRMS YES, THIS NEWLY EXPOSED PLAYA IS CAUSING MORE DUST TO BE KICKED UP IN THOSE AREAS, THEY FOUND 10% OF THE PARTICLES IN AREAS AROUND THE SALTON SEA, PARTICLES LINKED WITH NEGATIVE EFFECTS ON HUMAN HEALTH, 10% IS COMING FROM THIS EXPOSED PLAYA. THEY DID THE SAMPLING IN 2015 AND 2016, THAT IS THE BAD NEWS. THE GOOD NEWS, WHEN THEY LOOKED AT THE CHEMICAL COMPOSITION THEY FOUND IT WAS NOT ESPECIALLY TOXIC COMPARED TO REGULAR DESERT DUST.WHAT TYPES OF IMPACTS, AND THIS CAUSE?THIS KIND OF DUST CAN INCREASE THE RISK OF HEART DISEASE, LUNG DISEASE AND OVERALL MORTALITY FOR PEOPLE LIVING AROUND THE AREA. IT IS JUST ABOUT THE KIND OF DUST THAT THIS IS. NORMAL DESERT DUST WHICH CONTRIBUTED TO 45% OF THIS PARTICULATE MATTER ARE ALREADY LINKED WITH THESE KINDS OF HEALTH PROBLEMS AND THE CONCERN HERE IS WE ARE GETTING MORE AND MORE OF THAT.HOW IS THIS DUST COMING OFF THE LAKEBED DIFFERENT THAN THE DIFFERENT DESERT DUST.IT IS DIFFERENT IN SOME WAYS, ONE OF THE WAYS IT IS DIFFERENT IS IT IS SALTIER. IT HAS MORE SODIUM, THAT IS TO BE EXPECTED. THE SALTON SEA IS SALTIER, SALTIER THAN THE OCEAN. WE HAVE MORE SODIUM IN THIS DUST AND RESEARCHERS SAY THAT COULD BE HAVING NEGATIVE ECOLOGICAL IMPACTS AROUND THE CITY BUT IT'S NOT A HUMAN HEALTH CONCERN. THEY FOUND THEY WERE DOSH THERE WERE ALSO HIGHER LEVELS -- THERE WERE HIGHER LEVELS OF OTHER ELEMENTS. THEY DID NOT EXCEED CALIFORNIA EPA THRESHOLDS, EXCEPT FOR ONE EXCEPTION, NICKEL DID EXCEED THE THRESHOLD, THREE TIMES OUT OF THE 24 TIMES THEY SAMPLED. OVERALL, LOW LEVELS OF TOXIC CHEMICALS IN THIS DUST COMPARED TO REGULAR DESERT DUST.THERE WERE CONCERNS THAT IT HAS BEEN SUSTAINED BY RUNOFF FOR LONG PERIODS OF TIME. IT HAS PESTICIDES, THE STUDY DOESN'T SHOW THERE IS A SIGNIFICANT AMOUNT OF PESTICIDES ENDING UP IN THE DUST FROM THE PLAYA?THEY FIND THE CHEMICALS ARE FAR BELOW THE THRESHOLD FOR WHAT WOULD BE CONCERNING. YOU ARE RIGHT IT HAS BEEN FOR DECADES, THIS AGRICULTURAL RUNOFF SINK AND IT IS PESTICIDES ACCUMULATING IN THEIR. THIS IS THE FIRST STUDY, AN EARLY STUDY, IT IS PRELIMINARY, EVIDENCE BUT IT DOES NOT CONFIRM THE WORST FEARS THAT SOME PEOPLE HAVE HAD.THE PROBLEM WITH THE EXPOSED LAKEBED IS ONLY EXPECTED TO GET WORSE. ESPECIALLY WHEN MEDICATION WATERS STOPPED BY THE END OF THE YEAR.UNDER A MAJOR WATER TRANSFER AGREEMENT, THE DISTRICT IS SCHEDULED TO STOP PUMPING WHAT IS KNOWN AS MITIGATION WATER INTO THE SALTON SEA AFTER THE END OF THE YEAR. THIS IS WATER THAT KEEPS IT FROM SHRINKING TOO RAPIDLY. WITH THAT WATER NOT FLOWING INTO THE SALTON SEA BY 2018, THERE IS CONCERN THAT THE SHRINKING WILL ACCELERATE, EXPOSING MORE PLAYA TO DESERT LANDS AND CONTRIBUTING MORE DUST. RIGHT NOW, WE SEE PLAYA DUST ACCOUNTING FOR 10% OF THAT MATTER OUT THERE, BUT THE CONCERN IS THAT COULD SPIKE AFTER IT STOPS RECEIVING THE MITIGATION WATER.WHAT IS BEING DONE FROM KEEPING MORE PLAYA BEING EXPOSED.THE IMPERIAL IRRIGATION DISTRICT HAS BEEN LAUNCHING PROJECTS OVER THE YEARS TO CREATE THINGS LIKE BIRD HABITATS, RE-FLOOD TO CERTAIN AREAS, CREATING WETLANDS, DEVELOP GEOTHERMAL ENERGY, ALL WITH THE GOAL OF TRYING TO KEEP DOWN THE NEW SOURCE OF DUST. THOSE PROJECTS WILL BE EXPENSIVE, THEY WILL TAKE A LONG TIME TO COME TO FRUITION. I THINK A LOT OF RESIDENTS, THEIR CONCERN IS WHAT WILL HAPPEN IN THE NEAR FUTURE AS THE SHRINKING OF THE SEA COULD START TO ACCELERATE.I HAVE BEEN SPEAKING WITH DAVID WAGNER, THANK YOU.

New Study Traces Airborne Dust Back To Shrinking Salton Sea
A new UC Riverside study provides some answers to the question of whether the shrinking Salton Sea is worsening air quality and hurting the health of nearby residents.

As the Salton Sea shrinks — exposing land that was once underwater to desert winds — one concern has been that increased dust emissions will make already poor air quality worse for nearby residents. A recently published study out of UC Riverside confirms this is already starting to happen.

"With drying up of the lake and exposing of the shoreline, we get an additional source of airborne dust," said UC Riverside associate professor of atmospheric science Roya Bahreini, who led the study. "And exposure to these particles can have health impacts for humans."

The researchers wanted to know how much of the airborne dust around the Salton Sea is actually coming from newly exposed lakebed, known as "playa." So they sampled airbone particulate matter at Bombay Beach and Salton City in August 2015 and again in February 2016.

They found that nearly 10 percent of the kind of particulate matter known to raise the risk of heart and lung disease came from playa. Forty-five percent came from desert sources. Man-made pollution also contributed to the particulates in the air the researchers sampled.

Though the contribution from playa emissions may seem relatively low now, Bahreini said it could increase sharply in the near future. Under a water transfer agreement, the Salton Sea is scheduled to stop receiving inflows of "mitigation" water from the Imperial Irrigation District at the end of 2017. That means the sea is likely to shrink more quickly.

"Contribution of the playa to airborne dust is going to increase because the water inputs are going to decrease significantly by the end of the year," Bahreini said.

The researchers also looked at the chemical composition of the airborne playa dust. They wanted to understand if pesticides that flowed into the Salton Sea for decades could make airborne playa dust more hazardous to human health, as some have feared.

But they found that while airborne playa dust was saltier and higher in some trace elements like calcium and selenium, it was not especially toxic compared to desert soils. The concentrations of toxic elements remained far below thresholds set by the California EPA. The only exception was the element nickel, which did exceed the agency's reference exposure levels during three of the 25 sampling periods.