Gruber's Grove Fish Tested

[Laura Olah <olah@speagle.com>]

Gruber's Grove Fish Tested
Elevated Mercury Levels Still Considered Safe, DNR says

MERRIMAC  This spring, the Wisconsin Department of Natural Resources (DNR)
did a mercury content analysis on fish collected in Gruber's Grove Bay
located on Lake Wisconsin just north of Sauk City.  The results contain both
good news and bad news.  The good news is that according to the copy of the
DNR memorandum dated August 10, 1999 and forwarded to CSWAB, none of the
mercury samples exceeded the mercury advisory limit of 0.5 ug/g.  Therefore,
no fish advisory is considered necessary.

The bad news is that the average mercury concentrations in largemouth bass
and walleye collected in Gruber's Grove Bay are higher than levels in
comparable sized fish of these species collected in other portions of Lake
Wisconsin.  The average mercury level in largemouth bass is 0.39 ug/g and in
walleyes is 0.28 ug/g.  The averages in tests conducted in 1993 were 0.16
ug/g for largemouth bass and 0.15 ug/g for walleyes. This shows that the
mercury concentrations in the fish have increased, in many cases doubled,
compared with the results of testing in 1993.

The discovery of contamination in bay sediments late last year prompted the
fish testing.   In November 1998, the DNR collected four sediment cores from
Gruber's Grove Bay, which is the outfall for all industrial wastewater
discharges from Badger Army Ammunition Plant.  Analysis at the State
Laboratory of Hygiene revealed high levels of several heavy metals and
ammonia.

Very high levels of mercury (24 mg/kg) and lead (800 mg/kg) pose threats to
humans and aquatic organisms from both bioaccumulation and direct toxicity,
the DNR said.  By comparison, mercury concentrations up to 4 mg/kg was the
focus of a contaminated sediment removal project at Starkweather Creek in
Dane County.

The correlation between the higher mercury concentrations in the Gruber's
Grove Bay fish and the high concentrations of mercury found in the sediments
is hard to determine.  The DNR feels that it bears further investigation.

DNR personnel propose to have sediment samples analyzed for methyl mercury
and look into the possibility of using caged fish to determine the potential
to bioaccumulate methyl mercury.  They will look into this further.

CSWAB, a local activist organization that has been working since 1990 to get
Badger Army Ammunition Plant cleaned up and restored for conservation, said
the DNR has promised to keep community members informed of further
discussion and possible actions.

*   *   *

Laura Olah, Executive Director
Citizens for Safe Water Around Badger
E12629 Weigand's Bay South
Merrimac, WI  53561
phone (608)643-3124
fax (608)643-0005 alt fax (608)643-2682
Email: olah@speagle.com
Website: http://www.speagle.com/cswab