SHELTON (May 24, 2007) – Harmful bacteria leaking from failing septic systems and other animal sources may be getting trapped in the top layer of tideland sediments in upper Oakland Bay. The bacteria may be growing stronger especially during the warm, summer months.
“Bacteria feeding on nutrients in the sediment can amplify the actual pollution problem,” said John Konovsky, environmental program manager for the Squaxin Island Tribe.
One piece of evidence to support the sediment theory is the relationship between wind and bacteria levels. The windier the conditions, the higher the fecal coliform counts. When the wind kicks up, the churning action of the water re-suspends sediment and any bacteria present.
The tribe is investigating this phenomena by collecting samples from the top gooey layer of sediment in the bay, and studying how fecal coliform in the sediment relate to the water column bacteria levels and wind conditions. “The tainted sediment isn’t the source of the pollution, but it can make a small pollution problem a lot worse,” said Konovsky. “The sediment could be masking the original source of pollution.”
Bacteria such as fecal coliform usually can’t survive long in saltwater and sunlight, but if they become trapped in the tideland sediments, nutrients stimulate the production of a chemical that allows the bacteria to persist. “When bacteria respond to nutrients in the sediment, they endure much longer and a little problem becomes a big problem,” said Konovsky. “It makes it all the more important to find the original bacteria sources no matter how small.”
About 60 acres at the head of Oakland Bay was downgraded to restricted shellfish harvest status by the state Department of Health on late last fall because of the fecal pollution. To rectify the bacteria problems, the Mason County Commissioners formed a Shellfish Protection District around Oakland Bay on this spring. It is the first action taken under the newly formed “Mason County Clean Water Initiative.”
Expansion of harvest closures in Oakland Bay would be disastrous for tribal harvesters and would hamstring the local shellfish industry, a vital part of the local economy. Over $10 million of shellfish is taken from the bay every year, including over 3 million pounds of clams and 1.8 million oysters.
“Tribal members always have depended on shellfish as a source of nutrition, for income and as a way of life” said Andy Whitener, natural resources director for the tribe. “We need to get a better idea of where the pollution is coming from and how to prevent it from further closing Oakland Bay shellfish beds.”
For more information, contact: John Konovsky, environmental program manager, Squaxin Island Tribe, (360) 432-3804. Emmett O’Connell, South Sound information officer, NWIFC, (360) 528-4304, [email protected].