This dataset includes fish scientific name, fish common name, site identification codes, latitude, longitude, site name, sample identification codes, collection date, tissue type, percent moisture content in fish samples, and wet and dry total mercury concentrations in fish tissues.

Biological indicators including morphometric (length, weight), age, sex and health indicators including organismal (health assessment index, condition factor), organ (hepatosomatic index, gonadosomatic index), cellular (intersex, parasite density, macrophage aggregate density), subcellular (plasma vitellogenin, estradiol, testosterone, 11-keto testosterone) and molecular (hepatic transcript abundance) were measured in smallmouth bass from tributaries in the Chesapeake Bay watershed. Total mercury was measured in these fish and correlations between mercury and biological indicators were assessed.

Biological indicators including morphometric (length, weight), age, sex and health indicators including organismal (health assessment index, condition factor), organ (hepatosomatic index, gonadosomatic index), cellular (intersex, parasite density, macrophage aggregate density), subcellular (plasma vitellogenin, estradiol, testosterone, 11-keto testosterone) and molecular (hepatic transcript abundance) were measured in smallmouth bass from tributaries in the Chesapeake Bay watershed. Total mercury was measured in these fish and correlations between mercury and biological indicators were assessed.

Comma-separated values (.csv) file containing data related to mercury in smallmouth bass (Micropterus dolomieu) collected from the Snake River, USA.

Comma-separated values (.csv) file containing data related to mercury in smallmouth bass (Micropterus dolomieu) collected from the Snake River, USA.

Data includes fine‑scale (1.5 cm minimum resolution) vertical solute concentrations for filtered methylmercury (ng/L), filtered total mercury (ng/L), dissolved organic carbon (mg/L), and dissolved chloride (micromole/L) in SixMile Brook, New York and McTier Creek, South Carolina. Vertical solute data were assessed one time at one site in each stream in 2009, at edge-of-water (margin) and center-of-channel (channel) using two mini-piezometer (USGS MINIPOINT) devices (seven 0.325 cm stainless steel tubes, 0.8 cm screened interval). Each MINIPOINT device was installed with sampling points in surface water and at approximately 1.5, 4.5, 7.5, 12.5, 17.5, 30, and 60 cm below the bed-sediment/surface-water interface.

Data includes fine‑scale (1.5 cm minimum resolution) vertical solute concentrations for filtered methylmercury (ng/L), filtered total mercury (ng/L), dissolved organic carbon (mg/L), and dissolved chloride (micromole/L) in SixMile Brook, New York and McTier Creek, South Carolina. Vertical solute data were assessed one time at one site in each stream in 2009, at edge-of-water (margin) and center-of-channel (channel) using two mini-piezometer (USGS MINIPOINT) devices (seven 0.325 cm stainless steel tubes, 0.8 cm screened interval). Each MINIPOINT device was installed with sampling points in surface water and at approximately 1.5, 4.5, 7.5, 12.5, 17.5, 30, and 60 cm below the bed-sediment/surface-water interface.

Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.

Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.

Under the Great Lakes Restoration Initiative, the U.S. Geological Survey Mercury Research Lab (USGS MRL) conducted a multiyear assessment of mercury across the Laurentian Great Lakes. Biannual sampling was conducted across all five lakes onboard the U.S. Environmental Protection Agency (US EPA) research vessel Lake Guardian (in years 2010–2014, 2018) at pelagic sampling locations established by the long-term US EPA Great Lakes monitoring program. In addition to the regularly scheduled biannual sampling, in September 2013 and 2014 Lake Michigan and Lake Erie (respectively) were sampled with increased focus on shallow nearshore locations. Throughout these sampling efforts, sediments, mussels, surface water, and plankton were collected from open-water locations within all five of the Great Lakes. Additionally, surface water from Great Lake tributaries were sampled by the USGS MRL and preceded (2005 or 2006) or overlapped (2010-2015) with the open lake sampling efforts. All surface water samples were analyzed for methylmercury, total mercury, and dissolved organic carbon. Plankton and mussel tissue were analyzed for methylmercury, total mercury, and carbon/nitrogen stable isotopes and concentrations (plankton only). Sediments were analyzed for methylmercury, total mercury, and carbon content.