Regional Applied Research Effort Mercury Source Identification and Risk Management Recommendations for Fish Tissue Consumption from Livestock Ponds on the Cheyenne River Sioux Tribal Lands


FY 2002
                         FFORT
   Through the Regional Applied Research Effort (RARE) ORD responds to the high priority,
   near-term research needs of EPA's Regional Offices. Annually, each EPA Region submits a
   project to an ORD Laboratory /Center where it is processed as an extramural research
   activity. Joint participation bystafffrom both the Laboratory and the Regional Office
   throughout the development of the project and through completion of the research fosters
   communication and collaboration between ORD and the EPA Regional Offices.

    REGION 8:  MERCURY SOURCE IDENTIFICATION AND RISK  MANAGEMENT

 RECOMMENDATIONS FOR  FISH TISSUE CONSUMPTION  FROM  LIVESTOCK  PONDS

                  ON  THE  CHEYENNE RIVER Sioux TRIBAL  LANDS
       Mercury contamination, and resultant health and
environmental effects after mercury exposure, has been
the focus of national and congressional importance in
recent years for the USEPA. The agency has outlined
the current state of knowledge for anthropogenic mer-
cury emissions in the U.S., Hg fate and transport, expo-
sure assessment,  Hg health effects, ecological Hg ef-
fects, and evaluation of Hg control technologies and
costs. Across Region 8 states, 55 fish advisories have
now been issued and more investigations are pending.
       In addition to the many non-point source pollu-
tion efforts to monitor and regulate mercury releases,
the Superfund program has been looking at mining-re-
lated point sources of Hg contamination. In a collabora-
tive 3 year study with the Cheyenne River Sioux Tribe
Department of Environmental Protection (CRST DEP),
and the Agencies' Environmental Response Team, Re-
gion VIII  investigated Hg levels in fish tissues from the
Cheyenne River and Lake Oahe in northwestern South
Dakota. In 2000, the CRST released a fish advisory rec-
ommending less consumption of fish, especially for sen-
sitive individuals within their population (pregnant and
elderly).
       One mitigating risk management recommenda-
tion from the CRST to its constituents was to consume
fish from livestock ponds, which, having no influence from
mining related  activities and  at the time, presumably
would have lower concentrations of mercury in fish tis-
sue. However, fish from livestock ponds with seemingly
similar outward appearances had significant differences
in accumulation in both the same species or within spe-
cies of the same trophic position. Therefore, the linger-
ing research questions are:
•  Can the means be developed to predict which ponds
will be safe to consume fish which inhabit them?
•  Can these ponds act as mesocosms to help under-
stand the bioconcentration of mercury in the larger wa-
ter bodies such as Lake Oahe?
       This research project  will attempt to address
the following issues:
1) Determine the source of mercury bioaccumulating in
fish tissue. The primary focus will be to determine if the
source of mercury ultimately accumulating in fish is ei-
ther anthropogenically related to aerial deposition or natu-
rally occurring sources related to geologic formation. In
doing so, a quantitative prediction of mercury loading
and bioaccumulation can be used to predict accumula-
tion.  Given the many factors which influence the fate
and transport of mercury, these stock ponds can be used
in a research mesocosm approach to help further under-
stand mechanisms of bioaccumulation of methylmercury
when there are no apparent point sources. Data collec-
tion will focus on input data needed for running models
developed by EPA ORD at the National Exposure Re-
search Laboratory in Athens, GA. These two models
will be used to estimate total watershed loading and iden-
tify principle loading components
2) Make risk management recommendations to tribal
members to reduce mercury exposure. The goal here
will be to use the results from the first objective to make
future fish stocking recommendations in ponds with the
least  potential for bioaccumulation of methylmercury. The
researchers will determine if there are defined sizes of
watersheds, geologic formation  (i.e. soil types), or physi-
cal parameters which can adequately predict a critical
health-based tissue burden in fish tissue.

               Regional Contact: Dale Hoff             ORD Contact: John Johnston

                            • us at http://www/epa.gov/osp/regions/rarefact.htm

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