These data were collected as part of the Southwest Alaska Inventory and Monitoring Network (SWAN) freshwater contaminants protocol. The protocol outlines a framework for monitoring mercury (Hg) concentrations in resident lake fish within SWAN parks. The primary goal of this monitoring is to understand the spatial differences, temporal trends, and health ramifications of Hg contamination in resident lake fish. Monitoring relies on total Hg in fish axial muscle as an indicator of methyl Hg exposure. It targets four high-priority lakes which vary in size, depth, wetland cover, glacial influence, and Hg concentration. These lakes are in Katmai National Park and Preserve (KATM). The focal species is lake trout (Salvelinus namaycush), a widespread, long lived, top predator in SWAN lakes. However, if other species are sampled as bycatch, they may be retained and analyzed if they represent species-specific data gaps in Hg concentration. Two broad types of data are generated from this protocol. The first type includes observations and measurements that are recorded while sampling and processing fish (e.g., length, weight, sex). The second type includes results of analyses performed by contract laboratories (e.g., age, total Hg). This particular dataset includes those two broad types of data for 40 fish sampled in 2021. Of those fish, all 40 were lake trout.

These data were collected as part of the Southwest Alaska Inventory and Monitoring Network (SWAN) freshwater contaminants protocol. The protocol outlines a framework for monitoring mercury (Hg) concentrations in resident lake fish within SWAN parks. The primary goal of this monitoring is to understand the spatial differences, temporal trends, and health ramifications of Hg contamination in resident lake fish. Monitoring relies on total Hg in fish axial muscle as an indicator of methyl Hg exposure. It targets four high-priority lakes which vary in size, depth, wetland cover, glacial influence, and Hg concentration. These lakes are located in two parks: Lake Clark National Park and Preserve (LACL) and Katmai National Park and Preserve (KATM). The focal species is lake trout (Salvelinus namaycush), a widespread, long lived, top predator in SWAN lakes. However, if other species are sampled as bycatch, they may be retained and analyzed if they represent species-specific data gaps in Hg concentration. Two broad types of data are generated from this protocol. The first type includes observations and measurements that are recorded while sampling and processing fish (e.g., length, weight, gender). The second type includes results of analyses performed by contract laboratories (e.g., age, total Hg). This particular dataset includes those two broad types of data for 49 fish sampled in 2019 and 2020 from 2 lakes in LACL: Lake Clark and Kijik Lake. Of those 49 fish, 40 were lake trout, 6 were burbot (Lota lota), 2 were Arctic grayling (Thymallus arcticus), and 1 was Arctic char (Salvelinus alpinus).

These data were collected as part of the Southwest Alaska Inventory and Monitoring Network (SWAN) freshwater contaminants protocol. The protocol outlines a framework for monitoring mercury (Hg) concentrations in resident lake fish within SWAN parks. The primary goal of this monitoring is to understand the spatial differences, temporal trends, and health ramifications of Hg contamination in resident lake fish. Monitoring relies on total Hg in fish axial muscle as an indicator of methyl Hg exposure. It targets four high-priority lakes which vary in size, depth, wetland cover, glacial influence, and Hg concentration. These lakes are located in two parks: Lake Clark National Park and Preserve (LACL) and Katmai National Park and Preserve (KATM). The focal species is lake trout (Salvelinus namaycush), a widespread, long lived, top predator in SWAN lakes. However, if other species are sampled as bycatch, they may be retained and analyzed if they represent species-specific data gaps in Hg concentration. Two broad types of data are generated from this protocol. The first type includes observations and measurements that are recorded while sampling and processing fish (e.g., length, weight, gender). The second type includes results of analyses performed by contract laboratories (e.g., age, total Hg). This particular dataset includes those two broad types of data for 49 fish sampled in 2019 and 2020 from 2 lakes in LACL: Lake Clark and Kijik Lake. Of those 49 fish, 40 were lake trout, 6 were burbot (Lota lota), 2 were Arctic grayling (Thymallus arcticus), and 1 was Arctic char (Salvelinus alpinus).

Comma-separated values (.csv) file containing data related to mercury in fishes collected from Clear Lake, California.

This data release includes results of raw water, soil, seston, and fish tissue samples collected from 14 lakes within Lake Clark National Park and Katmai National Park between 2007 and 2017. Specifically, these data include total mercury and methylmercury concentrations in water, size-sieved seston, and particulate matter. Additionally, these data include soil and volcanic ash measurements from the surrounding watersheds. Finally, these data include energetic profiling of seston, lake trout (Salvelinus namaycush), and sockeye salmon (Oncorhynchus nerka) as well as mercury isotope measurements of the fishes. These data, except for Lake Clark data, were use in interpreting mercury mass balance flows and bioavailability to the food web and are a part of an associated journal article published in Environmental Science and Technology Letters (https://doi.org/10.1021/acs.estlett.2c00096). Lake Clark data include mercury and methylmercury concentrations in water, seston, and fish tissue from 2011 and 2012. Mercury isotope measurements were not collected as part of this assessment. These data were used to understand drivers of bioaccumulation within predator fish from southwest Alaska and are part of an associated journal article published in Environmental Pollution (https://doi.org/10.1016/j.envpol.2023.121678).

This data release includes results of raw water, soil, seston, and fish tissue samples collected from 14 lakes within Lake Clark National Park and Katmai National Park between 2007 and 2017. Specifically, these data include total mercury and methylmercury concentrations in water, size-sieved seston, and particulate matter. Additionally, these data include soil and volcanic ash measurements from the surrounding watersheds. Finally, these data include energetic profiling of seston, lake trout (Salvelinus namaycush), and sockeye salmon (Oncorhynchus nerka) as well as mercury isotope measurements of the fishes. These data, except for Lake Clark data, were use in interpreting mercury mass balance flows and bioavailability to the food web and are a part of an associated journal article published in Environmental Science and Technology Letters (https://doi.org/10.1021/acs.estlett.2c00096). Lake Clark data include mercury and methylmercury concentrations in water, seston, and fish tissue from 2011 and 2012. Mercury isotope measurements were not collected as part of this assessment. These data were used to understand drivers of bioaccumulation within predator fish from southwest Alaska and are part of an associated journal article published in Environmental Pollution (https://doi.org/10.1016/j.envpol.2023.121678).

These data represent Hg concentrations in tissue from 104 analyses of fish samples collected at 7 sites in streams/rivers and lakes during 2004 to 2013 within or near to Bad River Tribal lands. Nine fish species are represented in this dataset. Most fish specimens were collected by the Bad River Tribe, but collection agency was not always indicated in source files.

The Northeast Stream Quality Assessment (NESQA) performed mercury (Hg) isotope analysis of prey fish, game fish, and sediments from 29 sites across an urban to forested land-use gradient. The data presented here includes the chemical analysis of Hg concentrations and isotopes, capture information for fish species, land use, and stream water quality variables. Using these parameters it was determined that the preservation of Hg isotope signatures, which are indicative of source (e.g. atmospheric deposition, industrial point discharge), were dependent on land use, proximity to point sources, and variables related urbanization (e.g. road density and impervious surface cover). Additional Information regarding the interpretation of this data set can be found in the corresponding journal article: (https://pubs.acs.org/doi/10.1021/acs.est.9b03394).

In 2021, the U.S. Geological Survey (USGS) Mercury Research Laboratory (MRL) conducted a large-scale assessment of mercury (Hg) concentrations and Hg stable isotope values in tributaries of Lake Superior in order to define the sources and amounts of Hg entering the lake. Water samples were collected monthly from 18 tributaries in the United States from April through October in 2021 and during 2022 spring melt (May 2022). As a complement, 10 tributaries on the Lake Superior Northshore were sampled three times a year (spring, summer, and fall) by Lakehead University and Lakehead Region Conservation Authority. Nine tributaries were also sampled twice per year (spring and summer) in Pukaskwa National Park by Parks Canada. Filtered total Hg (THg) concentrations from United States and Canadian Northshore ranged from 0.2 to 8.8 nanograms per liter (ng L-1), with a median value of 1.2 ng L-1. Unfiltered THg in Pukaskwa National Park ranged from 0.6 to 5.0 ng L-1 with a median of 3.2 ng L-1, but encompassed both the filtered and particulate bound Hg. Median methylmercury (MeHg) values were approximately 0.1 ng L-1 for both filtered and unfiltered waters, but could reach levels greater than 1 ng L-1 during higher flow events. THg and MeHg concentrations were positively correlated to dissolved organic carbon (DOC) concentrations for most tributaries. Hg loads to Lake Superior were calculated for U.S. tributaries using the R package loadflex ( http://dx.doi.org/10.1890/ES14-00517.1 ), median loads for THg were 18 grams per day, but could increase to 590 grams per day under high flow and snow melt conditions.

As part of the larger Great Lakes Cooperative Science and Monitoring Initiative (CSMI) , the U.S. Geological Survey Mercury Research Laboratory (MRL) completed a binational assessment partnering with the U.S. Environmental Protection Agency (US EPA), Environmental Climate Change Canada (ECCC), Michigan-DNR (MI-DNR), University of Minnesota-Duluth Natural Resources Research Institute (UM-NRRI), and the National Oceanographic and Atmospheric Association (NOAA), to assess contaminant concentrations within seston, mussels, preyfish, waters, and surface sediments within Lake Huron. All matrices were assessed for mercury and methylmercury concentrations to examine spatial trends of mercury within the lakes. Sediments were also analyzed for total mercury stable isotope composition to approximate sources of mercury contamination to the lake.