Drying Salton Sea has caused dangerous pollution, health problems for nearby communities, study finds

SAN DIEGO (CN) — Back in 2003, farmers in California's Imperial Valley agreed to send some of their Colorado River water to cities on the coast. The deal was touted as a win for thirsty Californians and a boon for efforts to conserve water.

But the deal also caused dangerous pollution for those living near the Salton Sea, according to a new study published in the American Journal of Agricultural Economics on Wednesday.

For the study, researchers looked at 20 years of daily air pollution data collected from around the inland and heavily saline Salton Sea between 1998 to 2018. As the water-transfer program reduced agricultural runoff that replenishes the sea, once-underwater lakebed was exposed to wind, leading to increased dust and air pollutants that can cause heart and respiratory issues, they found.

Airborne particulate concentrates of PM₁₀ and PM_2.5 in dust pollution are particularly harmful to people. PM_2.5 can get deep into lungs and the bloodstream, causing problems with the hearts and lungs.

“Atmospheric PM_2.5 due to dust storms has been shown to decrease birth weight and increase infant mortality,” the researchers wrote in their study. And both types of pollutants increased as water flows to the Salton Sea decreased and the sea shrunk, they found.

Cross-referencing this data with health-screening information that tracks conditions like asthma by zip code, researchers concluded that dust from the exposed lakebed was driving up rates of asthma and other health problems in communities around the sea.

They warned about the consequences of water deals like the one in 2003, which — though perhaps good for Californians elsewhere — caused harm for people living near the sea, including majority Latino communities and nearby Indigenous governments.

“Imperial County’s population is 80% Hispanic and 10.5% Black, meaning it is a community made up almost entirely of historically marginalized groups that have predominantly not been included in the political decisions to transfer the water," the researchers wrote. They noted that 20% of children in Imperial County were estimated to have asthma, compared to just 8.3% for the U.S. population overall. What's more, "Imperial County has two times the rate of pediatric asthma-related emergency room visits relative to California."

Eric Edwards, an assistant professor of agricultural and resource economics at the University of California in Davis and an author of the study, compared the situation in the Salton Sea to another Californian water-related fiasco.

In the early 20th century, officials drained Owens Lake to supply water for Los Angeles — causing the lakebed to become the largest source of particulate pollution in the country. In the years since, L.A. Department of Water and Power users have spent more than $2.5 billion on dust mitigation efforts in the area.

Edwards said he and other researchers would continue to study how the drying Salton Sea is affecting health outcomes for nearby residents. Going forward, he hoped officials would "include these groups that are going to be impacted in the planning and mitigation policies.”

The impacts, he warned, might affect not just U.S. communities but settlements in Mexico, including the nearby city of Calexico.

"The border doesn’t stop this dust,” he said.

In some ways, the history of the Salton Sea is itself a story of human folly.

Over millions of years, the changing course of the Colorado River has cyclically flowed into a large basin that covers parts of Imperial County, Riverside County and Baja California. Those periodic flows created a large inland sea called Lake Cahuilla, which supported the Cahuilla, Kumeyaay and Cocopah Indigenous communities.

In the early 20th century, when the lakebed was dry, engineers attempted to build an irrigation canal to funnel water from the Colorado into the valley to quench the growing demands of the burgeoning agricultural industry. Floodwaters breached the canal and flowed into the dry lakebed, creating the current Salton Sea.

As the agriculture industry grew, farm runoff fed the sea and kept it from evaporating. In the 1950s, state officials added fish from the Gulf of California to create a sport fishery.

The fish attracted migratory birds, who needed a place to rest and eat especially as California drained others wetlands and marshes for development. The birds enticed birdwatchers, which attracted investment in the 1950s and '60s, leading to resort towns along the sea like Bombay Beach that in turn attracted Hollywood stars and other tourists.

But farm runoff is not the same as river water — and the Salton Sea was in trouble. The water grew saltier than the ocean and became increasingly contaminated with pesticides, causing greater numbers of fish and then birds to die. Far from a recreation destination, the Salton Sea became a cautionary tale.

In 2003, the Imperial Irrigation District signed a massive agreement to send more water from the river to cities on the coast.

Officials planned for projects to conserve the sea. At the same time, California agricultural industry was under increasing pressure to save water, causing even less inflows. The Salton Sea continued to recede, exposing dust from that lakebed that contained toxins like selenium and DDT. Pollutants like these now drift in the winds around Southern California — but even today, thousands of people still call communities around the sea home.

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