This data release includes sampling location data, field-collected water chemistry data, cation and anion concentration data for water and tissues of submerged aquatic vegetation, aquatic insect larvae, adult aquatic insects and riparian spiders from 35 first- and second-order sub-alpine streams that ranged over several orders of magnitude in metal concentrations but were similar in elevation, geology, and stream morphology. Sampling was completed in late summer, after snowmelt runoff was complete and as the streams approached baseflow conditions.

The U.S. Geological Survey is monitoring concentrations of metals and other trace elements in streambed sediment and aquatic invertebrates in post-wildfire watersheds in five western states including California, Oregon, Montana, Colorado and New Mexico. This data release makes available major and minor trace element concentrations in bed sediment and aquatic invertebrates collected from 2022-2024.

Biogeochemical processes are key drivers of chemical solubility and mobilization. Understanding these processes will lead to improved predictive capabilities and may aid with watershed management decisions. This data release presents results from the Boulder Creek, Colorado watershed, including analyses of water and sediment. From April to August 2019, water samples were collected weekly at 2 sites along Boulder Creek and 4 tributary sites draining into Boulder Creek. In August 2022, water samples were collected every 2 hours for 34 hours at 2 sites on Boulder Creek (upstream and downstream of the city of Boulder). Samples for both studies were analyzed for major cations and anions, dissolved organic carbon, UV absorbance, total dissolved nitrogen, ammonium, nitrate, alkalinity, trace metals, water isotopes, and field parameters including dissolved oxygen, pH, water temperature, and specific conductance. In August 2022, bed sediment (0-3 cm depth) samples were collected at 8 sites along Boulder Creek. The sediment was dried, sieved, pulverized, digested, and then analyzed for metals, total carbon, sulfur, and carbonate. In 2021 and 2022, laboratory incubations of sediment and stream water were conducted to assess how different oxidation-reduction conditions affect metal and nutrient concentrations. Sediment cores (0-5 cm and 5-10 cm depth) and surface water were collected from Boulder Creek at three sites upstream, within, and downstream of the city of Boulder. Samples were collected from incubation reactors over time and analyzed for major cations and anions, dissolved organic carbon, UV absorbance, total dissolved nitrogen, ammonium, nitrate, trace metals, total arsenic, pH, and specific conductance. Sediments used for the incubations were further characterized by sequential extractions with hydroxylamine and dithionite and analyzed for major cations and trace metals. Site information, soil characterization details, incubation preparation and biogeochemical nutrient data, sediment sequential extraction data, and water-quality data are presented in this data release as ten comma-separated values (.csv) formatted tables. A data dictionary file describes the data found in the .csv files. Method details and references are located in the metadata file “Boulder Creek Watershed Data (2019-2023).xml.”

Biogeochemical processes are key drivers of chemical solubility and mobilization. Understanding these processes will lead to improved predictive capabilities and may aid with watershed management decisions. This data release presents results from the Boulder Creek, Colorado watershed, including analyses of water and sediment. From April to August 2019, water samples were collected weekly at 2 sites along Boulder Creek and 4 tributary sites draining into Boulder Creek. In August 2022, water samples were collected every 2 hours for 34 hours at 2 sites on Boulder Creek (upstream and downstream of the city of Boulder). Samples for both studies were analyzed for major cations and anions, dissolved organic carbon, UV absorbance, total dissolved nitrogen, ammonium, nitrate, alkalinity, trace metals, water isotopes, and field parameters including dissolved oxygen, pH, water temperature, and specific conductance. In August 2022, bed sediment (0-3 cm depth) samples were collected at 8 sites along Boulder Creek. The sediment was dried, sieved, pulverized, digested, and then analyzed for metals, total carbon, sulfur, and carbonate. In 2021 and 2022, laboratory incubations of sediment and stream water were conducted to assess how different oxidation-reduction conditions affect metal and nutrient concentrations. Sediment cores (0-5 cm and 5-10 cm depth) and surface water were collected from Boulder Creek at three sites upstream, within, and downstream of the city of Boulder. Samples were collected from incubation reactors over time and analyzed for major cations and anions, dissolved organic carbon, UV absorbance, total dissolved nitrogen, ammonium, nitrate, trace metals, total arsenic, pH, and specific conductance. Sediments used for the incubations were further characterized by sequential extractions with hydroxylamine and dithionite and analyzed for major cations and trace metals. Site information, soil characterization details, incubation preparation and biogeochemical nutrient data, sediment sequential extraction data, and water-quality data are presented in this data release as ten comma-separated values (.csv) formatted tables. A data dictionary file describes the data found in the .csv files. Method details and references are located in the metadata file “Boulder Creek Watershed Data (2019-2023).xml.”

This dataset presents the results of analysis of aquatic biota tissue samples, collected over multiple sampling events from in from 2007 to 2014 at three sites (Las Vegas Bay, Overton Arm, and Boulder Basin) in Lake Mead National Recreational Area. The tissue samples were analyzed for concentrations of Carbon 13 and Nitrogen 15 isotopes by the University of California, Davis in Davis, California. Data are presented in 1 spreadsheet worksheet that is organized by year, location, and taxa. General trophic level (Vander Zanden and Rasmussen, 1999) and calculations of benthic reliance (Umek and others, 2010) also are included. Combined data from sampling events in 2007 and 2008 previously were published in Umek and others, 2010. Common species names are used in the spreadsheet and scientific names can be found in the metadata.

Abstract The purpose of this sampling was to collect matched aquatic insect and water samples to support metals mixture toxicity modeling. This is part of a larger study that included exposing naturally colonized insect communities to metals mixtures in long-term laboratory toxicity tests, field surveys, and modeling (Schmidt and others, 2019). The Panther Creek sampling was conducted to give a field comparison to laboratory exposures of aquatic insect communities to cobalt (Co) plus copper (Cu) mixtures, the results of which were presented as part 4 of Schmidt and others (2019). The water samples from the Panther Creek area were collected to interpret metals concentrations in the tissues of mayflies and caddisflies relative to experimental exposures and to compare to community composition. Samples were collected from sites expected to give a gradient of metals concentrations, ranging from natural background reference sites to concentrations expected to be high enough to produce substantial bioaccumulation of metals. Results The results are presented in a workbook consisting of 6 datasheets which respectively include data on: 1. Summary: includes sampling locations and summarized matched water and tissue samples 2. Water-detailed: Field measurements and analytical results of water sampling 3. Tissue-detailed: Analytical results of insect tissue analyses 4. Benthic macroinvertebrates: Counts of benthic macroinvertebrate samples that coincided with the water and tissue samples 5. Water-QC: Results of quality control analyses associated with the water samples 6. Tissue-QC: Results of quality control analyses associated with the tissue samples For the 12 environmental stream samples from the Panther Creek watershed, Co values ranged from <0.01 to 329 µg/L and Cu values ranged from 0.2 to 24 µg/L. Dissolved organic carbon ranged from 0.72 to 2.2 mg/L, pH ranged from 7.1 to 8.8 units, alkalinity ranged from 8 to 50 mg/L as CaCO3, and hardness ranged from 17 to 167 mg/L as CaCO3. Approximate diel swings in pH for Panther Creek, measured at the Deep Creek campground prior to sunrise and in late afternoon were 0.4 units, and in Big Deer Creek at the mouth measured in early morning and late afternoon, the changes were less than 0.1 units. Cobalt and copper tissue concentrations ranged widely in the insects. Cobalt values ranged from 0.4 to 634 mg/kg dry weight in insect tissues and copper values ranged from 12 to 1080 mg/kg. Funding was from USGS Mineral Resources Program, and the Panther Creek sampling was conducted in cooperation with the Blackbird Mine Site Group. References Schmidt, T.S., Mebane, C.A., Miller, J.L., and Balistrieri, L.S., 2019, Effects of metal mixtures on aquatic insect communities in experimental streams: cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), and zinc (Zn): US Geological Survey Data Release, also available at http://dx.doi.org/10.5066/P9XXBSAK

Abstract The purpose of this sampling was to collect matched aquatic insect and water samples to support metals mixture toxicity modeling. This is part of a larger study that included exposing naturally colonized insect communities to metals mixtures in long-term laboratory toxicity tests, field surveys, and modeling (Schmidt and others, 2019). The Panther Creek sampling was conducted to give a field comparison to laboratory exposures of aquatic insect communities to cobalt (Co) plus copper (Cu) mixtures, the results of which were presented as part 4 of Schmidt and others (2019). The water samples from the Panther Creek area were collected to interpret metals concentrations in the tissues of mayflies and caddisflies relative to experimental exposures and to compare to community composition. Samples were collected from sites expected to give a gradient of metals concentrations, ranging from natural background reference sites to concentrations expected to be high enough to produce substantial bioaccumulation of metals. Results The results are presented in a workbook consisting of 6 datasheets which respectively include data on: 1. Summary: includes sampling locations and summarized matched water and tissue samples 2. Water-detailed: Field measurements and analytical results of water sampling 3. Tissue-detailed: Analytical results of insect tissue analyses 4. Benthic macroinvertebrates: Counts of benthic macroinvertebrate samples that coincided with the water and tissue samples 5. Water-QC: Results of quality control analyses associated with the water samples 6. Tissue-QC: Results of quality control analyses associated with the tissue samples For the 12 environmental stream samples from the Panther Creek watershed, Co values ranged from <0.01 to 329 µg/L and Cu values ranged from 0.2 to 24 µg/L. Dissolved organic carbon ranged from 0.72 to 2.2 mg/L, pH ranged from 7.1 to 8.8 units, alkalinity ranged from 8 to 50 mg/L as CaCO3, and hardness ranged from 17 to 167 mg/L as CaCO3. Approximate diel swings in pH for Panther Creek, measured at the Deep Creek campground prior to sunrise and in late afternoon were 0.4 units, and in Big Deer Creek at the mouth measured in early morning and late afternoon, the changes were less than 0.1 units. Cobalt and copper tissue concentrations ranged widely in the insects. Cobalt values ranged from 0.4 to 634 mg/kg dry weight in insect tissues and copper values ranged from 12 to 1080 mg/kg. Funding was from USGS Mineral Resources Program, and the Panther Creek sampling was conducted in cooperation with the Blackbird Mine Site Group. References Schmidt, T.S., Mebane, C.A., Miller, J.L., and Balistrieri, L.S., 2019, Effects of metal mixtures on aquatic insect communities in experimental streams: cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), and zinc (Zn): US Geological Survey Data Release, also available at http://dx.doi.org/10.5066/P9XXBSAK

The dataset reports biological endpoints (survival, growth, developmental stage, and body burden of selected metals) for larval spadefoot toads (Spea multiplicata) in laboratory-based exposures to 1) field-collected water or sediment from a containment pond at the Pinyon Plain Mine in Arizona, USA, during its pre-production phase and 2) six concentrations of copper or cobalt in water-only bioassays. Also reported are data on water quality and the concentration of metals in the test media during the assays.

This U.S. Geological Survey (USGS) data release contains data from stream water, groundwater, and stream sediment samples collected in August 2023 in the East Mancos River watershed in southwestern Colorado. Data were collected as part of a study aimed at identifying sources of elevated metal concentrations in the stream. Eighteen streambank wells were installed in pairs at nine locations to capture the emerging groundwater from the left and right banks (relative to downstream-facing direction) and a synoptic sampling campaign was conducted to quantify stream metal loads. A continuous, instream injection of sodium bromide (NaBr) was initiated at the head of the ~17 km study reach prior to the synoptic sampling campaign and maintained throughout the duration of the study. Bromide concentrations were subsequently used to determine streamflow in the upper ~2.7 km of the stream using the tracer-dilution method. Streamflow was quantified for tributaries and locations farther downstream using data from a series of sodium chloride slug additions wherein specific conductivity readings were used as a surrogate for the tracer concentration. Stream and groundwater samples, including the wells and inflows from the left (LBI) and right (RBI) banks, were collected mainly in the upper ~0.9 km of the stream course (primary study reach). Environmental tracer data were collected to better understand groundwater flowpaths to the stream. Stream sediment samples, including some ferricrete samples, were also collected to help identify potential instream and near-stream metal sources.

The data presented include concentrations of 10 metals in sediments and composite larval amphibian tissues from 20 wetlands across the United States. Sixteen of the wetlands were sampled in 2019 and four were sampled in 2015-2016. Where possible both larval anurans (frogs and toads) and salamanders were collected from each wetland. The data also include information on metal concentrations in amphibian tissues after the gut contents were removed to understand metal bioaccumulation potential and the molar ratio of selenium to mercury in each tissue composite sample. This data release supports the following publication: Smalling, K.L., Oja, E.B., Cleveland, D.M., Davenport, J.M., Eagles-Smith, C., Grant, E.H.C., Kleeman, P.M., Halstead, B.J., Stemp, K.M., Tornabene, B.J., Bunnell, Z.J. and Hossack, B.R., 2021, Metal accumulation varies with life history, size, and development of larval amphibians: Environmental Pollution, https://doi.org/10.1016/j.envpol.2021.117638.