Detailed Research Information

Detailed project information for
Study Plan Number 02095

Branch : Aquatic Ecology Branch

Study Plan Number : 02095

Study Title : Effects of Stream Water Chemistry on Mercury Concentrations in Brook Trout in Shenandoah National Park

Starting Date : 10/01/2003

Completion Date : 03/31/2006

Principal Investigator(s) : Snyder, Craig

Primary PI : Snyder, Craig

Telephone Number : (304) 724-4468

Email Address : csnyder@usgs.gov

SIS Number :

Primary Program Element :

Second Program Element :

Status : Completed

Abstract : BACKGROUND
The National Park Service, in collaboration with scientists from the U.S. Geological Survey and the University of Virginia, proposes a comparative watershed study designed to determine the distribution, abundance, and variability of mercury in fish within Shenandoah National Park, and to assess the relationship between stream water chemistry and mercury accumulation in brook trout, the primary game species in the park. The goal of the study is to ensure that mercury contamination poses no threat to humans or fish populations in the park. Results of the study will: (1) provide data needed to evaluate human health risks associated with the consumption of contaminated fish in Shenandoah National Park (SNP), (2) determine the potential for acute or chronic problems with trout populations associated with Hg accumulation and toxicity, and (3) improve our understanding of the factors governing the bioavailability of mercury in stream ecosystems. The study will make use of the extensive water chemistry database developed as part of the Shenandoah Watershed Assessment Study (SWAS) to provide the basis for sample site selection and the context for interpreting data.

Mercury (Hg) is a toxic element that naturally occurs in aquatic systems in very low concentrations. Past human use of the metal for industrial and agricultural purposes has resulted in serious contamination of many surface waters. Even in remote, relatively pristine areas where direct anthropogenic inputs are lacking, long-range atmospheric transport of Hg from fossil fuel combustion and other sources has led to increased concentrations in freshwater systems and biota (Downs et al. 1998, Fitzgerald et al. 1998). Concentrations of Hg sufficient to prompt fish consumption advisories (i.e., > 0.5 ug/g) have been reported for predatory fish from relatively remote areas with no on-site anthropogenic or geologic sources of Hg (e.g., Abernathy and Cumbie 1977, Bodaly et al. 1984).

The chemistry of Hg is complex and consequently its behavior is difficult to predict in nature. Total mercury concentrations in the environment have not been found to be effective predictors of bioaccumulation in fish. Depending on physical, chemical, and biological conditions at a site, Hg can remain largely tied up in sediments, released from sediments to the water column, be lost to the atmosphere, be transported with sediment particulate matter to other locations, or be taken up by aquatic biota where it may concentrate and become a threat to humans and other fish-eating animals (reviewed in Ulirich et al. 2001). Although the precise factors controlling the accumulation of Hg in aquatic biota are not fully understood, it is clear that fish and other aquatic species are much more efficient in accumulating methylmercury (MMHg) than the inorganic forms that predominate in the abiotic component of the environment (Mason et al. 1995). Thus, factors that influence the rate in which in inorganic Hg is transformed to MMHg also influence bioaccumulation as well.
Although the process of Hg methylation is complex, the results of numerous studies on contaminated lakes indicate that enhanced Hg methylation rates and bioaccumulation have been consistently linked to low pH, low salinity, and the presence of organic matter in low oxygen environments (reviewed in Ullrich et al. 2001). The relationship between water chemistry and Hg methylation has not been fully investigated in stream ecosystems.

Streams in SNP vary considerably in terms of pH and other important water chemistry parameters due to variation in dominant bedrock class underlying individual catchments. All the streams in SNP are characterized by low salinnity or ionic strength. Streams underlain by siliciclastic bedrock have low acid neutralizing capacities (ANC) and consequently very low pH. As a result of their low pH, these streams may be the most vulnerable to mercury contamination. Streams underlain by basaltic bedrock have higher ANC and pH. Streams underlain by granitic bedrock have intermediate ANC and pH. We thus expect that bedrock distribution in SNP may reflect a gradient in watershed response to atmospheric deposition of mercury.
OBJECTIVES
The goal of the study is to ensure that mercury contamination poses no threat to humans or fish populations in the park. The specific objectives are to determine the distribution, abundance, and variability of Hg in fish in Shenandoah National Park, and to assess the relationship between stream water chemistry and Hg concentrations in brook trout, the primary game species in the park.
PUBLICATIONS
Synder, C.D., R. Webb, J. Atkinson, and S. Spitzer. 2006. Effects of stream water chemistry on mercury concentrations in brook trout in Shenandoah National Park. Final report submitted to the National Park Service. 25pp.

For More Information : /aeb/mercury_report.pdf

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Branch :	Aquatic Ecology Branch
Study Plan Number :	02095
Study Title :	Effects of Stream Water Chemistry on Mercury Concentrations in Brook Trout in Shenandoah National Park
Starting Date :	10/01/2003
Completion Date :	03/31/2006
Principal Investigator(s) :	Snyder, Craig
Primary PI :	Snyder, Craig
Telephone Number :	(304) 724-4468
Email Address :	csnyder@usgs.gov
SIS Number :
Primary Program Element :
Second Program Element :
Status :	Completed
Abstract :	BACKGROUND The National Park Service, in collaboration with scientists from the U.S. Geological Survey and the University of Virginia, proposes a comparative watershed study designed to determine the distribution, abundance, and variability of mercury in fish within Shenandoah National Park, and to assess the relationship between stream water chemistry and mercury accumulation in brook trout, the primary game species in the park. The goal of the study is to ensure that mercury contamination poses no threat to humans or fish populations in the park. Results of the study will: (1) provide data needed to evaluate human health risks associated with the consumption of contaminated fish in Shenandoah National Park (SNP), (2) determine the potential for acute or chronic problems with trout populations associated with Hg accumulation and toxicity, and (3) improve our understanding of the factors governing the bioavailability of mercury in stream ecosystems. The study will make use of the extensive water chemistry database developed as part of the Shenandoah Watershed Assessment Study (SWAS) to provide the basis for sample site selection and the context for interpreting data. Mercury (Hg) is a toxic element that naturally occurs in aquatic systems in very low concentrations. Past human use of the metal for industrial and agricultural purposes has resulted in serious contamination of many surface waters. Even in remote, relatively pristine areas where direct anthropogenic inputs are lacking, long-range atmospheric transport of Hg from fossil fuel combustion and other sources has led to increased concentrations in freshwater systems and biota (Downs et al. 1998, Fitzgerald et al. 1998). Concentrations of Hg sufficient to prompt fish consumption advisories (i.e., > 0.5 ug/g) have been reported for predatory fish from relatively remote areas with no on-site anthropogenic or geologic sources of Hg (e.g., Abernathy and Cumbie 1977, Bodaly et al. 1984). The chemistry of Hg is complex and consequently its behavior is difficult to predict in nature. Total mercury concentrations in the environment have not been found to be effective predictors of bioaccumulation in fish. Depending on physical, chemical, and biological conditions at a site, Hg can remain largely tied up in sediments, released from sediments to the water column, be lost to the atmosphere, be transported with sediment particulate matter to other locations, or be taken up by aquatic biota where it may concentrate and become a threat to humans and other fish-eating animals (reviewed in Ulirich et al. 2001). Although the precise factors controlling the accumulation of Hg in aquatic biota are not fully understood, it is clear that fish and other aquatic species are much more efficient in accumulating methylmercury (MMHg) than the inorganic forms that predominate in the abiotic component of the environment (Mason et al. 1995). Thus, factors that influence the rate in which in inorganic Hg is transformed to MMHg also influence bioaccumulation as well. Although the process of Hg methylation is complex, the results of numerous studies on contaminated lakes indicate that enhanced Hg methylation rates and bioaccumulation have been consistently linked to low pH, low salinity, and the presence of organic matter in low oxygen environments (reviewed in Ullrich et al. 2001). The relationship between water chemistry and Hg methylation has not been fully investigated in stream ecosystems. Streams in SNP vary considerably in terms of pH and other important water chemistry parameters due to variation in dominant bedrock class underlying individual catchments. All the streams in SNP are characterized by low salinnity or ionic strength. Streams underlain by siliciclastic bedrock have low acid neutralizing capacities (ANC) and consequently very low pH. As a result of their low pH, these streams may be the most vulnerable to mercury contamination. Streams underlain by basaltic bedrock have higher ANC and pH. Streams underlain by granitic bedrock have intermediate ANC and pH. We thus expect that bedrock distribution in SNP may reflect a gradient in watershed response to atmospheric deposition of mercury. OBJECTIVES The goal of the study is to ensure that mercury contamination poses no threat to humans or fish populations in the park. The specific objectives are to determine the distribution, abundance, and variability of Hg in fish in Shenandoah National Park, and to assess the relationship between stream water chemistry and Hg concentrations in brook trout, the primary game species in the park. PUBLICATIONS Synder, C.D., R. Webb, J. Atkinson, and S. Spitzer. 2006. Effects of stream water chemistry on mercury concentrations in brook trout in Shenandoah National Park. Final report submitted to the National Park Service. 25pp.
For More Information :	/aeb/mercury_report.pdf
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U.S. Department of the Interior \|\| U.S. Geological Survey 11700 Leetown Road, Kearneysville, WV 25430, USA URL: http://www.lsc.usgs.gov Maintainer: lsc_webmaster@usgs.gov Last Modified: October 21, 2002 dwn Privacy Policy and Disclaimers \|\| FOIA \|\| Accessibility