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Final summary of the laboratory culture and toxicity testing of juvenile western pearlshell (Margaritifera falcata) native to the western United States: Expansion of freshwater mussel water and sediment toxicity testing methods
Citation:
Wang, N., J. Kunz, C. Ivey, C. Ingersoll, C. Barnhart, B. Glidewell, B. Shephard, AND T. Norberg-King. Final summary of the laboratory culture and toxicity testing of juvenile western pearlshell (Margaritifera falcata) native to the western United States: Expansion of freshwater mussel water and sediment toxicity testing methods. U.S. Environmental Protection Agency, Washington, DC, 2015.
Impact/Purpose:
A Regional Applied Research Effort project with EPA Region 10, ORD and USGS was initiated as a result of a baseline ecological risk assessment (BERA) problem formulation for the Upper Columbia River (UCR) site in northwest Washington. The UCR site is a 165-mile stretch of the Columbia River between Grand Coulee Dam and the U.S.-Canadian border. A portion of the baseline BERA problem formulation for the UCR includes assessing sediment toxicity with mussels. About 37% of the 300 freshwater mussel species in the U.S. are listed as either threatened, endangered, or are candidates for listing as threatened or endangered species. The Unionid mussel (fatmucket, Lampsilis siliquoidea) is native to the Mississippi and Illinois River systems, and is used in water only toxicity tests. However, native mussels to the Northwest are the greatest conservation concern in the rivers. One of the goals of the research was to expand both the number of mussel species from fatmucket to include other species that can be used for toxicity testing in water column and sediment experiments. Following a literature review of the various Pacific Northwest freshwater mussels, the Western pearlshell (Margaritifera falcata) was chosen for method development. The focus of this project was on development of methods for collecting, culturing, and conducting both water column and sediment toxicity tests with freshwater mussels native to the western US. Testing of mussels requires the collection of adults, establishing laboratory cultures, and evaluating methods for conducting toxicity tests (e.g., test conditions, test acceptability criteria). During the study, the juvenile western pearlshell were successfully propagated in the laboratory over two seasons for acute toxicity testing, the grow-out of juveniles for up to six months in culture was low. Acute 96-h toxicity test results for the pearlshell were compared the results of five unionid species for 10 chemicals (with modes of action of narcosis, metallic stress, respiratory toxicity). The pearlshell was about equally or less sensitive for all the chemicals. For the chronic testing, survival of >80% was observed under control conditions in several 28-d water and sediment treatments when tests were initiated with 3-mo pearlshell; however, the control survival of the pearlshell in two subsequent chronic 28-day water-only chromium toxicity tests was problematic. Unfortunately, a sediment toxicity test was not be performed due to high mortality of juvenile pearlshell in the culture and insufficient numbers of mussels >1.0 mm in length available. The mussel sediment toxicity test method is still in development. These results will be finalized with a joint USGS/EPA ORD and Region 10 peer-reviewed journal publication(s) on the comparative sensitivity of early life stages of the selected species in acute and chronic water column exposures relative to the sensitivity of other standard test species. Applicable data will be incorporated to EPA’s Web-ICE toxicity database. EPA Region 10 plans to use the unionid data for the BERA. As Region 10 has over 20 years of experience using early life stage marine mussel, bivalve, and echinoderm toxicity test procedures for assessments, the use of a freshwater mussel test would allow expanding on the limited number of invertebrate species for rivers and stream assessments.
Description:
A Regional Applied Research Effort project with EPA Region 10, ORD and USGS was initiated as a result of a baseline ecological risk assessment (BERA) problem formulation for the Upper Columbia River (UCR) site in northwest Washington. The UCR site is a 165-mile stretch of the Columbia River between Grand Coulee Dam and the U.S.-Canadian border. A portion of the baseline BERA problem formulation for the UCR includes assessing sediment toxicity with mussels. About 37% of the 300 freshwater mussel species in the U.S. are listed as either threatened, endangered, or are candidates for listing as threatened or endangered species. The Unionid mussel (fatmucket, Lampsilis siliquoidea) is native to the Mississippi and Illinois River systems, and is used in water only toxicity tests. However, native mussels to the Northwest are the greatest conservation concern in the rivers. One of the goals of the research was to expand both the number of mussel species from fatmucket to include other species that can be used for toxicity testing in water column and sediment experiments. Following a literature review of the various Pacific Northwest freshwater mussels, the Western pearlshell (Margaritifera falcata) was chosen for method development. The focus of this project was on development of methods for collecting, culturing, and conducting both water column and sediment toxicity tests with freshwater mussels native to the western US. Testing of mussels requires the collection of adults, establishing laboratory cultures, and evaluating methods for conducting toxicity tests (e.g., test conditions, test acceptability criteria). During the study, the juvenile western pearlshell were successfully propagated in the laboratory over two seasons for acute toxicity testing, the grow-out of juveniles for up to six months in culture was low. Acute 96-h toxicity test results for the pearlshell were compared the results of five unionid species for 10 chemicals (with modes of action of narcosis, metallic stress, respiratory toxicity). The pearlshell was about equally or less sensitive for all the chemicals. For the chronic testing, survival of >80% was observed under control conditions in several 28-d water and sediment treatments when tests were initiated with 3-mo pearlshell; however, the control survival of the pearlshell in two subsequent chronic 28-day water-only chromium toxicity tests was problematic. Unfortunately, a sediment toxicity test was not be performed due to high mortality of juvenile pearlshell in the culture and insufficient numbers of mussels >1.0 mm in length available. The mussel sediment toxicity test method is still in development. These results will be finalized with a joint USGS/EPA ORD and Region 10 peer-reviewed journal publication(s) on the comparative sensitivity of early life stages of the selected species in acute and chronic water column exposures relative to the sensitivity of other standard test species. Applicable data will be incorporated to EPA’s Web-ICE toxicity database. EPA Region 10 plans to use the unionid data for the BERA. As Region 10 has over 20 years of experience using early life stage marine mussel, bivalve, and echinoderm toxicity test procedures for assessments, the use of a freshwater mussel test would allow expanding on the limited number of invertebrate species for rivers and stream assessments.