Odor advisory issued for Salton Sea area; hydrogen sulfide leads to rotten-egg smell

An odor advisory was issued Sunday for the Salton Sea area in Riverside County due to elevated levels of a gas that smells like rotten eggs, according to state air regulators.

The advisory was issued for the Coachella Valley and will remain in effect until at least Monday because of winds from the south, with peak concentrations of hydrogen sulfide emissions occurring in the morning hours, the South Coast Air Quality Management District said in a statement.

“Hourly average concentrations of hydrogen sulfide peaked [Sunday] morning at 239 parts per billion immediately downwind of the Salton Sea - at a monitor close to the shore, in an area with little population,” the district said.

The standard for outdoor levels of hydrogen sulfide is 30 parts per billion over one hour. At that level, most individuals can smell the odor and some may experience symptoms such as headaches and nausea, the district said. However, those symptoms are temporary and do not cause any long-term health effects.

Hydrogen sulfide is associated with the natural processes occurring in the Salton Sea, a non-draining body of water with no ability to cleanse itself. Trapped in its waters are salt and selenium-laden agricultural runoff from surrounding farms, as well as heavy metals and bacterial pollution that flow in from Mexico’s New River, authorities said.

The Salton Sea was created in 1905 when the Colorado River broke through a silt-laden canal and roared unimpeded for two years into a basin near Brawley known as the Salton Sink. It eventually grew into a 360-square-mile lake that straddles Riverside and Imperial counties.

But the lake has shrunk over the years and recently has become an environmental hazard prone to choking dust storms.