Warnings posted for Rattlesnake Lake
October 2, 2008 · Updated 2:44 PM
NORTH BEND _ As the temperature rises people usually flock to
local recreation areas to combat the summer heat. However, Seattle
Public Utility (SPU) officials are warning swimmers to stay out of
Rattlesnake Lake right now because they have found a high amount of bacteria in the water.
Warning signs have been placed around the popular swimming and fishing destination since June 4, and so far there are no plans to officially close the area, said Ralph Naess, the public education specialist for SPU.
"It's a warning that you might have an increased risk of getting ill,"
he said. "If you want to swim, you can; but we don't recommend it."
But the warnings didn't stop Preston resident Michael
Dennett from fly fishing and kayaking in the lake last Thursday.
"I have no cuts or scars and I don't believe the bacteria will harm me because I didn't digest it," he said.
"It's a gamble. If the bacteria are high,
it's high. You just hope for the best."
The bacteria that are polluting the 111-acre lake are called
fecal coliform, which is a non-deadly form of E. coli. The bacterium does its damage only when a person ingests the tainted water. Common ailments from fecal coliform include digestive problems, diarrhea, cramping and flu-like symptoms.
Low amounts of fecal coliform, which are produced from animal
and human waste, are commonly found in swimming areas. However,
when more than 200 bacteria colonies are found in a milliliter of water, the King County health department advises officials to post warning signs about the potential dangers.
"You don't want people ingesting the water. It's the human fecal coliform that will cause most of the problems," said Curt Horner, an environmental health specialist with Public Health
_ Seattle & King County. "If someone already has the flu, a person swimming in that could get the flu, so we worry more about human feces than animal feces."
"But the animal feces is certainly not good for you," he added.
Test counts earlier this week revealed that there were more than
4,000 Colony Forming Units (CFU) in the lake. Counts taken on June 21
revealed that bacteria counts at Rattlesnake Lake ranged from 50 to 19,000 CFU.
To put the numbers in perspective, Naess said, a pure waste
specimen could contain a couple million
SPU officials are not sure what type of waste is causing the
numbers to jump this summer. Several candidates include geese, dogs and even humans. The department plans to conduct a $15,000 DNA test to determine the source of the waste; however, those results probably won't be available until the end of they year.
In the meantime, SPU will continue to search for more clues on
how to solve the fecal coliform problem and learn what they can do to
prevent a re-infestation.
Naess said that one contributing factor might be that when the
water recedes in the fall and winter, geese and dogs might do their "business"
on the newly drained areas. Then when the lake's level rises in the spring and summer, the waste mixes with the water causing the undesirable bacteria.
Another theory is that diapers, otherwise known as "floating bags of bacteria," are being thrown into the lake or left along the shore. Any and all of these possibilities could be the cause of the problem, but again, officials won't know until more studies are done.
SPU will continue taking water samples from the lake three times
a week and won't take away the warning signs until bacteria counts
show up lower than 200 CFUs for three consecutive days.
Right now, there is no threshold CFU number that would make
officials immediately shut down the lake, Naess said.
"Our desire is that we never have to put up these signs again," he
said. "We may decide that if this just keeps on and we can't find a solution,
we may decide to try and prevent people from swimming here."
"But that's way out; it would be the most severe thing," Naess added.
For more information about the latest conditions at Rattlesnake
Lake, call (425) 831-5933.