PORT TOWNSEND — A new warning will be added this week to the yellow caution signs at Anderson, Leland and Gibbs lakes.
Just underneath the suggestion that all fish be cleaned and the guts discarded will be the following wording:
“Warning — algae toxins may be present in fish tissue. For more information, please call 360-385-9444” — the phone number for Jefferson County Public Health.
The change in the signs, which are supplied by the state Department of Health, was not prompted by any change in the lakes’ algae content.
None of the three lakes posted with the caution signs has visible blooms. No large amounts of toxin have been found in the water. Fishing is permitted in the lakes.
Caution signs went up early this month because minuscule amounts of toxin-producing algae were found in water samples.
The change in wording was prompted by a March 2010 study by the state Department of Ecology of fish in six lakes, including Anderson and Leland in East Jefferson County.
The study, which is supported by research elsewhere, found that the toxin microcystin, which can cause liver failure, accumulates in muscle tissue — the part of the fish that is eaten.
That’s a change from earlier research indicating that the toxin accumulated only in the viscera, which is usually discarded.
No studies, including Ecology’s last year, have linked consumption of fish from lakes with toxic algae to an effect on human health, said Dr. Tom Locke, public health officer for Jefferson and Clallam counties.
“We now have pretty clear information that one of the toxins produced by blue-green algae does get into the tissue of the fish,” he said.
“Since we know that the toxin is in the fish, we felt we needed to advise people of that.
“People need to factor that in when considering how much of the fish to eat.”
Anderson Lake, in particular, is one of the Peninsula’s most popular trout fishing holes.
Health authorities can’t say how much fish is safe to eat.
“We can’t give specific advice on how much is safe or if [members of the public] should restrict their intake,” Locke said.
“We do know that when the algae is present, there is toxin in the fish.
“Whether there’s a significant health consequence or not is unknown. We can expect that question to eventually be answered in the research that’s on-going.
Public health authorities say that the risk appears to be more from long-term exposure than from infrequent ingestion of fish.
“It takes a fairly long time to build up the toxins in your body that would cause liver damage,” said Greg Thomason, Jefferson County environmental health specialist, citing studies of people who developed liver failure after years of drinking water from lakes containing toxic algae.
“You would have to eat a lot of fish over a long period of time,” he said.
Locke said that Ecology’s test results were not consistent, and that more study is needed.
“Consumption of fish containing blue-green algae toxins represents a poorly-studied, but potentially important, exposure route for humans,” says the Ecology study, which can be found at http://tinyurl.com/65kq9me.
It concludes: “Follow-up study is recommended to obtain higher quality microcystin data that can be used to better assess the human health risk.”
Microcystin can kill quickly if a large amount is ingested.
“We’re nowhere near those toxins levels when talking about the flesh of fish,” Locke said.
“The real concern in fish is that low levels can act as a liver toxin.”
No toxin in found in fish when no algae is present.
The liver can clean small, infrequent amounts of microcystin out of the body, but if a person ingests the poison over a long period of time in a constant supply, “eventually it wears the liver out,” Thomason said.
Microcystin is one of the two blue-green algae toxins that have been discovered historically in some East Jefferson County lakes, especially Anderson Lake, a
The other algae toxin found in Jefferson County lakes, anatoxin-a, doesn’t accumulate in tissues.
Anatoxin-a, a potent neurotoxin, is more likely than microcystin to kill quickly. It’s the toxin responsible for the deaths of two dogs who drank water from Anderson Lake in May 2006.
Those death led to the closure of the lake and the beginning of county monitoring of Anderson, Leland and Gibbs lakes.
No lakes in Clallam County are tested. The policy is to wait for an algae bloom, Locke said.
“The lakes in Clallam County appear to be very different than the three in Jefferson County that we’re monitoring,” Locke said.
Algae tends to grow in older, shallower lakes, such as Lake Anderson, rather than cold, deep lakes.
Updates on weekly tests of samples from Anderson, Leland, Gibbs and Sandy Shore lakes are at http://tinyurl.com/6z64ofy.
If an algae bloom is spotted in a Clallam County lake, it should be reported to the county environmental health division at 360-417-2258.
________
Managing Editor/News Leah Leach can be reached at 360-417-3531 or leah.leach@peninsuladailynews.com.
