EPA finds algae in stream is all natural

Reports that a stream running through the Deer Grove Forest Preserve near Palatine had turned milky green and smelled like detergent prompted visits Saturday by the Illinois Environmental Protection Agency and area fire departments.

IEPA emergency workers went to the stream near Quentin and Lake-Cook roads and determined the substance is a naturally occurring blue-green algae bloom, said spokeswoman Jill Watson.

Blue-green algae is bacteria that sometimes forms when nutrient-rich, stagnant water meets warm weather.

"It can look like someone painted the water when in high concentration," said Joe Ferencak, a program manager with the Department of Natural Resources. "They're not as common as regular algae but still occur."

In addition to its bright color, a blue-green algae bloom can produce an earthy or sewagelike smell.

IEPA tests contradict accounts by the Barrington Fire Department, which reported the unusual color and smell was caused by a runoff of algaecide from a nearby lake.

Deputy Chief John Feit said his understanding was authorities traced the substance back to a small pond on Carlisle Drive in Inverness, just west of the forest preserve.

He said the privately owned pond was being treated with algaecide that overflowed into storm sewers and into the forest preserve.

Whatever the case, experts say to stay away.

"Some forms of blue-green algae emit toxins that can irritate the skin," said Ferencak. "Definitely don't bathe in it or ingest it."

The algae can also kill off fish due to oxygen depletion.