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Lake's Algae Levels Jump Sharply, Researcher Finds: Pollution Levels Well Below EPA Limits

Posted on: Tuesday, 9 May 2006, 12:03 CDT

By Katie N Johannes, The Bellingham Herald, Bellingham, Wash.

May 9--It's no surprise that Lake Whatcom had more blue-green algae, less oxygen and more phosphorus in 2005 than in previous years.

What is surprising to researchers is how fast it's changing.

The Lake Whatcom Monitoring Project 2004/2005 Final Report describes a lake going through natural changes at an unnaturally rapid rate. That could lead to an inhospitable environment for just about everything except algae and the bacteria that break them down.

"Changes over tens of thousands of years are normal," said Robin Matthews, director of the Western Washington University Institute for Watershed Studies and the primary researcher for the report. "What's not normal are changes in a short enough time frame that a scientist can watch it."

For the more than 86,000 Bellingham-area residents who drink the water, the biggest public health hazard is created during the treatment process: more carcinogenic byproduct is released when there's more blue-green algae. But those and all other pollution levels are still well below the Environmental Protection Agency's prescribed limits.

"I'm still drinking water from the tap," Matthews said. "It's the cleanest dirty water I've ever studied."

Matthews has been monitoring the overall condition of the lake for the city of Bellingham since 1986. The city paid $450,000 two years ago for the latest contract for research.

One of the most dramatic changes in Lake Whatcom during the past couple of summers has been the increase in blue-green algae, which Matthews explained is actually bacteria.

Charts in the report show a slow increase in bacteria every summer since 1992, then a near vertical line representing a sharp increase since 2004.

"It's an exponentially increasing of numbers in the blue-green algae," she said. "The past couple of years I had to reset the scale I use to plot them, and I've been using the same scale as I used for two decades."

The sharp rise in blue-green algae is one symptom of a circuit of problems, which can be blamed largely on an increase in phosphorus washing into the lake off of pavement and rooftops.

Phosphorus is a naturally occurring substance, but without adequate storm-water controls, streets and buildings don't allow the ground to filter it out before it gets to the lake.

Blue-green algae eats the phosphorus, the same way plants in a garden draw it out of fertilizer. When the algae dies, the bacteria that feed off of it use up oxygen, choking off the supply for fish and other plants.

Low oxygen sets up an environment that more easily allows mercury and phosphorus to be released from sediments on the bottom of the lake. That's how mercury gets into the food chain, and phosphorus exacerbates the algae problem.

The low oxygen supply landed Lake Whatcom on the state Department of Ecology list of impaired water bodies in 1998. Ecology is working on models that project the condition of the lake over time, and they will help establish regulations for increasing oxygen. SLOWING PROGRESS Matthews said that even though the technology is available to clean up toxic water bodies, reversing the lake's problems now is going to be much less labor intensive than waiting until it turns toxic.

"The cost for going backwards is going to be much more expensive," she said.

Steven Hood, a water quality engineer for the state Department of Ecology, said the greatest hope for slowing the lake's degradation is to improve storm-water controls, allowing water to seep through the ground slowly rather than run directly into the lake.

"The best lead we have is to go back to stuffing the water into the ground," he said. "When water filtrates into the ground, it leaves a lot of the phosphorus behind."

He suggested convincing developers and homeowners to make use of rain gardens, and said the city and county should come up with incentives.

"If people are willing to live with a spongy lawn for the wettest part of the year, it's not such a big expense."

Reach Katie N. Johannes at katie.johannes@bellinghamherald.com or call 756-2805.

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Copyright (c) 2006, The Bellingham Herald, Bellingham, Wash.

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Source: The Bellingham Herald, Wash.

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