LONGMONT — Health officials late Friday afternoon began monitoring air quality around a stinky pond south of the city after warning nearby residents to evacuate if they suffer health problems because of the stench.
An algae bloom in Little Gaynor Lake, located southeast of Oxford Road and 95th Street, is causing the pond to produce large amounts of hydrogen sulfide, a gas that smells like rotten eggs, according to health workers.
The lake is probably not emitting dangerous levels of the gas, Boulder County Public Health environmental health chief Jeff Zayach said.
“We want to rule out any health concern,” he said. “We’re going to be monitoring 24 hours a day.”
Homeowners living near the lake began noticing the stench weeks ago.
“It’s like a bad septic tank,” resident Aine Loomis said Thursday. “It wakes you up at night.”
Marjorie McGinty, a south Longmont resident, said in a phone message Friday that she periodically noticed the stink from her house, which is 3 miles north of the pond.
The health department’s hotline, 303-441-1460, urges residents to evacuate and see a doctor if they experience headaches, nausea, eye irritation, confusion, seizures or tremors.
Health officials took their first readings Friday at the pond with a hard-to-find portable hydrogen sulfide meter borrowed from the state health department.
“We’re getting readings. It’s nothing alarming,” said Iris Sherman, an environmental health specialist with Boulder County Public Health.
On Monday, workers will install four stationary meters around the lake that will check air quality every 30 seconds for a week, Zayach said.
Officials monitored hydrogen sulfide levels at Sombrero Marsh on Boulder’s east side in 2000 after that pond began emitting an obnoxious smell. Despite the odor, the gas never reached dangerous levels, he said.
Ecologists refer to Little Gaynor Lake and Sombrero Marsh as “prairie potholes,” low-lying natural bodies of water that are not fed by running water, county spokesman Jim Burrus said.
The algae bloom that triggered the stench and reddish water color at Little Gaynor Lake occurred naturally and was likely caused by record heat in July, Burrus said.
Officials will avoid treating the water with chemicals because it is a wildlife sanctuary managed by Boulder County Parks and Open Space, Burrus said. However, they may dump barley hay in the water to curb algae growth.
Brad Turner can be reached at 720-494-5420, or by e-mail at bturner@times-call.com.
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