OH: Grand Lake St. Marys’ fish test negative for liver toxin
St. Marys, Ohio — Officials have removed a warning not to eat
fish from Ohio’s largest inland lake after tests of fish there
showed no signs of a liver toxin.
The Ohio Environmental Protection Agency announced the results Feb.
7. Ohio’s DNR collected fish samples in October from Grand Lake St.
Marys in western Ohio.
The 13,000-acre lake has been plagued by toxic blue-green algae
that led to warnings to avoid contact with the water or eating the
Samples from four species were analyzed to see if a toxin produced
by the algae builds up over time. Researchers tested tissue from
largemouth bass, bluegill, black crappie and channel catfish.
The EPA says officials plan to analyze more fish from the lake and
other state-owned lakes with the blue-green algae.
The state DNR collected fish samples in October and will take more
in April, June and August. The study will cost about $58,500.
The study will allow Ohio EPA scientists to determine whether to
permanately lift the “do not eat” fish consumption advisory, keep
it in place, or modify it to recommend eating a limited number of
fish per month from the lake.
The first fish samples were collected by DNR staff in October. They
have been preserved and will be compared to fish samples that will
be taken from the lake in April, June and August 2011 to determine
if extremely high levels of microcystin recorded in the lake pose a
long-term health risk to humans who consume the fish.
The state issued a “do not eat” advisory for fish taken from Grand
Lake St. Marys last summer after microcystin levels in the water
spiked to more than 2,000 parts per billion (ppb). Microcystin
above 20 ppb is considered high risk to humans for recreational
contact, such as swimming and water skiing, by the World Health
Other studies on microcystin in fish tissue indicate there is no
significant bioaccumulation when fish are exposed to lower levels
of the toxin.
However, these studies did not look at the effects of microcystin
at the extremely high levels recorded at Grand Lake St. Marys last
summer. The state issued the “do not eat” advisory as a precaution
until actual fish tissue data is available.
The complete study will allow the state to make a more informed
decision about future fish consumption advisories at Grand Lake St.
Marys and other Ohio lakes that may experience high algal toxin
A report on the study is expected late this year. The study is
funded by the state.