As the Salton Sea shrinks, a toxic mess looms

The Salton Sea, the largest lake in California, is drying up, revealing a bed packed with toxic chemicals, the residue of a century of runoff from Imperial Valley farms. Public-health experts worry that those chemicals pose a grave risk to the health of people who live nearby, mostly farmworkers, the elderly and families too poor to relocate, as Lindsay Fendt reports in FERN’s latest story, published with The Weather Channel.

“The lake was formed in 1905, after the Colorado River breached an irrigation canal and flooded the Salton Sink, a basin in the desert that has periodically held lakes throughout history,” Fendt writes. “Once the canal was repaired, two years later, the Salton Sea had no source of water other than the runoff that flowed in from the nearby farms of the Imperial Valley, one of the state’s agricultural hubs.

“This runoff water, full of chemicals and nitrates, was saltier than the lake water. As it drained through the soil, it combined with ancient salt deposits, raising the salinity even further, and in the 1970s scientists started warning that change was coming to the Salton Sea. The salt would transform the lake, causing it to shrink and making it inhospitable to wildlife.

“Sure enough, before the decade was up, fish started dying off and bird populations declined. The lake began to stink, spurring the state to issue periodic odor advisories that sometimes extended as far away as Los Angeles. Today, the lake is about twice as salty as the Pacific Ocean.

“Now the Salton Sea has another problem: Climate change is making this dry region even drier. And a growing demand for water in the booming cities and suburbs of Southern California has reduced the amount of Colorado River water diverted to nearby farms. In the coming years these two factors are expected to dramatically increase the pace at which the lake shrinks, exposing more lake bed and the agricultural toxins trapped in the mud. 

“The desert winds lift dust from the lakebed, and scientists fear that eventually the toxic residue of more than a century of agricultural runoff will be blown into the air — and into the lungs of residents. The area surrounding the Salton Sea already has some of the worst air quality in the country, caused by particulate matter swept up from farms and the desert. Local residents have some of the highest rates of asthma and other respiratory problems in the state, and public health officials say the heavy metals and chemicals in the lake bed pose an even greater threat.”