Montana Fish, Wildlife, and Parks (MT FWP), in collaboration with the United States Geological Survey (USGS) Wyoming-Montana Water Science Center (WY-MT WSC), Montana Department of Environmental Quality (MDEQ), and the United States Environmental Protection Agency (USEPA) collected fish from the Koocanusa Reservoir in 2021 for tissue analysis. Fish tissue collected included muscle, eggs, liver, and whole body. Analysis of tissues included characterization of the concentration of selenium, mercury and methyl mercury, nitrogen and carbon stable isotopes, and vitamins A and E. The purpose of these analyses was to inform state and federal management agencies on transboundary coal mining impacts to downstream fish health.

This data release includes laboratory analyses for fish tissue samples collected from Lake Koocanusa and the Kootenai River Basin in Montana during 2022. Samples were collected by the U.S. Geological Survey (USGS) Wyoming-Montana Water Science Center (WY-MT WSC) in cooperation with Montana Fish, Wildlife and Parks (MT FWP) and Montana Department of Environmental Quality (MT DEQ). Analyses include histology, percent moisture, carbon and nitrogen stable isotopes, and concentrations for 62 elements, including selenium, mercury, and methylmercury. This data release also compiles laboratory quality-assurance and quality-control data associated with the samples.

This data release includes laboratory analyses for fish tissue samples collected from Lake Koocanusa and the Kootenai River Basin in Montana during 2022. Samples were collected by the U.S. Geological Survey (USGS) Wyoming-Montana Water Science Center (WY-MT WSC) in cooperation with Montana Fish, Wildlife and Parks (MT FWP) and Montana Department of Environmental Quality (MT DEQ). Analyses include histology, percent moisture, carbon and nitrogen stable isotopes, and concentrations for 62 elements, including selenium, mercury, and methylmercury. This data release also compiles laboratory quality-assurance and quality-control data associated with the samples.

This data release includes laboratory analyses for fish tissue samples collected from Lake Koocanusa and the Kootenai River Basin in Montana during 2022. Samples were collected by the U.S. Geological Survey (USGS) Wyoming-Montana Water Science Center (WY-MT WSC) in cooperation with Montana Fish, Wildlife and Parks (MT FWP) and Montana Department of Environmental Quality (MT DEQ). Analyses include histology, percent moisture, and 30 elements, including selenium, mercury, and methylmercury. This data release also compiles laboratory quality-assurance and quality-control data associated with the samples.

Working in cooperation with EPA, the USGS coordinated the collection of fish tissue for processing and analyses by the EPA Region 10 Manchester Environmental Laboratory located in Port Orchard, WA. This effort was being tied to existing operations work performed by state wildlife agencies in Idaho and Montana (Ross et al. 2018). Annually, in late August and September, the Idaho Department of Fish and Game (IDFG), the Montana Department of Fish, Wildlife and Parks (MTFWP), and the Kootenai Tribe of Idaho conduct population surveys on the Kootenai River. During the 2018 electrofishing population surveys, state wildlife agency personnel also retained collected fish for this effort. The following were key design components of fish collection in the Kootenai River: (1) Fish were caught and analyzed for selenium and mercury in multiple tissues (filet, whole body, and/or egg/ovaries) as available to assess baseline contamination/bioaccumulation in fish species between Libby Dam and downstream of Bonners Ferry, ID. (2) Fish were caught from the mainstem Kootenai River in early September 2018 and analyzed for selenium and mercury from immediately downstream of Libby Dam (tailwater), downstream of Troy, MT, downstream of the ID/MT border, and in the proximity of Shorty’s Island downstream of Bonner’s Ferry. (3) The EPA Region 10 laboratory provided in-kind support for selenium and mercury analyses for the 142 fish samples collected. EPA Region 10 also provided data and sample management support via the Scribe Project Manager (RSCC). More details of the study design are given by USEPA and USGS (2018). Results: A total of 142 fish representing 13 species were retained for tissue analysis. Eggs were obtained from two species, kokanee salmon and mountain whitefish. In kokanee salmon, eggs were found in two fish from only site KR13 (Kootenai River below Libby Dam) and ranged from 4.17 to 5.01 mg/kg selenium as dry weight (dw). Eggs were found in mountain whitefish from all sites except the most downstream site sampled, KR4 (Kootenai River near Shorty’s Island). Selenium concentrations in mountain whitefish eggs ranged from 11.6 to 24.8 mg/kg (dw). An objective of the study was to compare selenium concentrations in fish and water to USEPA nationally recommended water quality criteria for selenium. The national criteria recommend that concentrations in fish eggs not exceed 15.1 mg/kg (dw), concentrations in whole-body of fish not exceed 8.5 mg/kg dry weight, or (b) concentrations in muscle tissue not exceed 11.3 mg/kg dry weight (USEPA 2016). For eggs, 6 of the 8 mountain whitefish egg samples exceeded EPA’s recommended value. No samples exceeded the whole-body criterion component of 8.5 mg/kg dry weight and no samples exceeded the muscle criterion component of 11.3 mg/kg dry weight. References: Ross, T.J., K. McDonnell, R. Hardy, and S. Stephenson. 2018. Kootenai River resident fish mitigation: white sturgeon, burbot, native salmonid monitoring and evaluation (Annual Progress Report May 1, 2016 — April 31, 2017). BPA Project # 1988-065-00, Idaho Department of Fish and Game. Report to the Bonneville Power Administration, Environment, Fish and Wildlife, Portland, OR. 118 pp. https://www.cbfish.org. USEPA. 2016. Aquatic Life Ambient Water Quality Criterion for Selenium – Freshwater 2016. 822-R-16-006, U.S. Environmental Protection Agency. 807 pp. https://www.epa.gov/wqc/aquatic-life-criterion-selenium [Accessed February 21, 2018]. USEPA and USGS. 2018. Kootenai River Fish Tissue Study Quality Assurance Project Plan. Prepared by U.S. Environmental Protection Agency, Regions 8 and 10, and U.S. Geological Survey, Idaho Water Science Center. 28 August 2018 (Revised 01 October 2018). 41 pp.

Working in cooperation with EPA, the USGS coordinated the collection of fish tissue for processing and analyses by the EPA Region 10 Manchester Environmental Laboratory located in Port Orchard, WA. This effort was being tied to existing operations work performed by state wildlife agencies in Idaho and Montana (Ross et al. 2018). Annually, in late August and September, the Idaho Department of Fish and Game (IDFG), the Montana Department of Fish, Wildlife and Parks (MTFWP), and the Kootenai Tribe of Idaho conduct population surveys on the Kootenai River. During the 2018 electrofishing population surveys, state wildlife agency personnel also retained collected fish for this effort. The following were key design components of fish collection in the Kootenai River: (1) Fish were caught and analyzed for selenium and mercury in multiple tissues (filet, whole body, and/or egg/ovaries) as available to assess baseline contamination/bioaccumulation in fish species between Libby Dam and downstream of Bonners Ferry, ID. (2) Fish were caught from the mainstem Kootenai River in early September 2018 and analyzed for selenium and mercury from immediately downstream of Libby Dam (tailwater), downstream of Troy, MT, downstream of the ID/MT border, and in the proximity of Shorty’s Island downstream of Bonner’s Ferry. (3) The EPA Region 10 laboratory provided in-kind support for selenium and mercury analyses for the 142 fish samples collected. EPA Region 10 also provided data and sample management support via the Scribe Project Manager (RSCC). More details of the study design are given by USEPA and USGS (2018). Results: A total of 142 fish representing 13 species were retained for tissue analysis. Eggs were obtained from two species, kokanee salmon and mountain whitefish. In kokanee salmon, eggs were found in two fish from only site KR13 (Kootenai River below Libby Dam) and ranged from 4.17 to 5.01 mg/kg selenium as dry weight (dw). Eggs were found in mountain whitefish from all sites except the most downstream site sampled, KR4 (Kootenai River near Shorty’s Island). Selenium concentrations in mountain whitefish eggs ranged from 11.6 to 24.8 mg/kg (dw). An objective of the study was to compare selenium concentrations in fish and water to USEPA nationally recommended water quality criteria for selenium. The national criteria recommend that concentrations in fish eggs not exceed 15.1 mg/kg (dw), concentrations in whole-body of fish not exceed 8.5 mg/kg dry weight, or (b) concentrations in muscle tissue not exceed 11.3 mg/kg dry weight (USEPA 2016). For eggs, 6 of the 8 mountain whitefish egg samples exceeded EPA’s recommended value. No samples exceeded the whole-body criterion component of 8.5 mg/kg dry weight and no samples exceeded the muscle criterion component of 11.3 mg/kg dry weight. References: Ross, T.J., K. McDonnell, R. Hardy, and S. Stephenson. 2018. Kootenai River resident fish mitigation: white sturgeon, burbot, native salmonid monitoring and evaluation (Annual Progress Report May 1, 2016 — April 31, 2017). BPA Project # 1988-065-00, Idaho Department of Fish and Game. Report to the Bonneville Power Administration, Environment, Fish and Wildlife, Portland, OR. 118 pp. https://www.cbfish.org. USEPA. 2016. Aquatic Life Ambient Water Quality Criterion for Selenium – Freshwater 2016. 822-R-16-006, U.S. Environmental Protection Agency. 807 pp. https://www.epa.gov/wqc/aquatic-life-criterion-selenium [Accessed February 21, 2018]. USEPA and USGS. 2018. Kootenai River Fish Tissue Study Quality Assurance Project Plan. Prepared by U.S. Environmental Protection Agency, Regions 8 and 10, and U.S. Geological Survey, Idaho Water Science Center. 28 August 2018 (Revised 01 October 2018). 41 pp.

These data were compiled to study mercury and selenium concentrations in fish species and assemblages in lotic waterbodies across the Upper Colorado River Basin. Data were compiled from State and Federal agencies. This data table contains raw concentration data, as well as standardized concentrations corrected for differences based on sample type (i.e., tissue type), species-specific bioaccumulation rates (Table S1), and fish size (Table S2). The data were used in linear mixed effects models to estimate average mercury and selenium concentration in fish species and in fish assemblages, including fish total length (cm), sampling location (Sub basin name and GPS coordinates), and sampling year (Figures 2,3, and 4 from manuscript).

These data were compiled to study mercury and selenium concentrations in fish species and assemblages in lotic waterbodies across the Upper Colorado River Basin. Data were compiled from State and Federal agencies. This data table contains raw concentration data, as well as standardized concentrations corrected for differences based on sample type (i.e., tissue type), species-specific bioaccumulation rates (Table S1), and fish size (Table S2). The data were used in linear mixed effects models to estimate average mercury and selenium concentration in fish species and in fish assemblages, including fish total length (cm), sampling location (Sub basin name and GPS coordinates), and sampling year (Figures 2,3, and 4 from manuscript).

This dataset includes analyses of selenium (Se) in water, sediment, periphyton, and benthic invertebrate and fish tissues from the Kootenai River in Idaho and Montana. The samples were collected as part of a study intended to evaluate selenium distribution and bioaccumulation in the aquatic food webs of the Kootenai River. Version 1.0 of this dataset includes complete food web sample results from our first three semi-annual sampling events (fall 2020, spring 2021, and fall 2021), in addition to more limited data from September 2018-2023 (mainly water sample results). Samples were collected from four sites on the Kootenai River between Libby Dam, Montana, and the border between Idaho, USA, and British Columbia, Canada. Sites were located at about 1, 81, 105, and 185 kilometers (km) downstream from Libby Dam. An additional comparison sampling site was on Lake Creek, near Troy, Montana. The water samples were analyzed for dissolved Se and Se species, including selenite, selenate, selenocyanate, methylseleninic acid, selenomethionine, and unknown Se species. Sediment samples were collected by scooping from depositional areas in shallow, quiescent water near the river edge. Sediment samples were sieved (63 micron pore size Nitex fabric) and analyzed for Se. Three types of periphyton and suspended particulates were sampled: periphyton scraped from rocks (PRS), periphyton grown on glass microscope slides (PSL), and suspended particulate material on flow-through filters (SPM). For invertebrates, whole-body tissues were analyzed from 43 distinct benthic invertebrate taxa, and multiple tissues were additionally analyzed for one taxon, the western pearlshell mussel, Margaritifera falcata. Five fish species were targeted for repeat sampling: mountain whitefish (Prosopium williamsoni), rainbow trout (Oncorhynchus mykiss), slimy sculpin (Cottus cognatus), redside shiner (Richardsonius balteatus), and northern pikeminnow (Ptychocheilus oregonensis). Occasional samples were also obtained from 4 additional species: kokanee (Oncorhynchus nerka), brown trout (Salmo trutta), longnose sucker (Catostomus catostomus), and largescale sucker (Catostomus macrocheilus). Fish were sometimes analyzed for whole body selenium concentrations, or dissected for separate analyses of muscle, liver, and egg-ovary tissues, and the carcass (everything leftover after the other tissues were removed). The specific tissue samples removed and analyzed varied by the sex and size of the fish, sampling event, and specific objectives. The total sample counts included in Version 1.0 of this dataset are 292 water sample results from 83 water samples, 27 sediment results, 114 periphyton results, 343 benthic invertebrate results, and 1,448 fish tissue results from 524 individual fish. Most analyses in the present dataset were for selenium with some additional analyses of mercury (Hg). Samples were collected and processed in collaboration with personnel from the Montana Fish, Wildlife, and Parks Department (MTFWP), Idaho Department of Fish and Game (IDFG), and the Kootenai Tribe of Idaho (KTOI). Laboratory analyses of water samples for Se were performed by Brooks Applied Laboratory, Seattle, WA. Laboratory analyses of solid phase samples were analyzed by the U.S. Geological Survey (USGS) Menlo (now Moffett) Selenium Laboratory, Menlo Park, CA; the U.S. Environmental Protection Agency’s (USEPA) Region 10 Manchester Environmental Laboratory, Manchester, WA; and by ALS Laboratory, Kelso, WA. Funding for this work was provided by a congressional appropriation to the USGS for mining-associated pollution monitoring in U.S. and British Columbia, Canada, transboundary watersheds.

The U.S. Geological Survey is studying Lake Koocanusa, a border reservoir between British Columbia in Canada and Montana, in collaboration with the Montana Department of Environmental Quality and the U.S. Environmental Protection Agency (Region 8). This work is part of a multi-agency project to apply an ecosystem-scale selenium modeling methodology (Presser and Luoma, 2010) to the lake to support development of a site-specific selenium guideline for the protection of aquatic life. This Data Release makes available measurements taken during the periods of May, 2015 to October, 2015 and April, 2016 to September, 2016. Spatially and temporally matched sets of dissolved and suspended particulate material selenium concentrations were collected mainly at two locations (forebay and international boundary) and at two depths (epilimnion, 3 meters below lake surface; hypolimnion, 3 meters above lake bottom). These data allow calculation of an environmental partitioning factor (i.e., Kd) between dissolved and suspended particulate material selenium concentrations as an initial modeling step. This Data Release contains 1) a location map; 2) a modeling schematic; 3) collection methods, analytical methods, and quality control information; 4) spreadsheets and graphical displays of selenium data; and 5) hydrological parameters related to sampling conditions at the lake. This Data Release will be updated and modified as additional sampling and analysis takes place.