Mysterious foam at Lake Mead officially deemed safe for swimmers

By Brian Nordli

Wednesday, June 12, 2013 | 10:05 p.m.

Pay no attention to the brown, foamy substance in the water at the Overton Arm of Lake Mead — officials have deemed the water nontoxic and safe for swimmers.

Lake Mead National Recreation Area park officials issued a precautionary advisory on June 8 after the substance and about 25 dead carp were found in a northern stretch of the lake. That advisory was lifted on Wednesday after investigation into the foam deemed it was nontoxic, although park officials still have not determined what it is.

“While we haven't received anything definitive as to the cause, we have reasonably evaluated the situation,” Christie Vanover, park spokeswoman, said in a press release. “Through all the scientific investigation, nothing dangerous to humans has been found.”

The park tested the foam samples with the Southern Nevada Water Authority, the Nevada Department of Wildlife and the Nevada Division of Environmental Protection. Water samples were found to be in the normal ranges of temperature, specific conductance, pH level and dissolved oxygen values, park officials said. The foam appeared to be made up of proteins from dead algae.

“It is unclear if the fish die-off was related to the foam,” said Vanover. “The foam does seem to be dissipating and no recently dead fish have been found. We will continue to observe the area with routine patrols."

Park officials recommend swimmers avoid any obvious patches of foam that have not dissipated.