A U.S. Geological Survey (USGS) scientist collecting a liver tissue sample from a wild-caught white sucker (Catostomus commersonii) from a river in the Great Lakes area.
Images
![USGS scientist collecting a liver tissue sample from a wild-caught white sucker](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/sampling_a_white_sucker.jpg?itok=zM_8o1vU)
A U.S. Geological Survey (USGS) scientist collecting a liver tissue sample from a wild-caught white sucker (Catostomus commersonii) from a river in the Great Lakes area.
Body surface tumor diagnosed as a squamous cell carcinoma on a white sucker fish
Body surface tumor diagnosed as a squamous cell carcinoma on a white sucker fish
![Lip tumor diagnosed as a papilloma on a white sucker](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/lip_tumor_on_white_sucker_brenda_ferris_l.jpg?itok=KGkcrdt1)
A lip tumor diagnosed as a papilloma on a white sucker (Catostomus commersonii) collected from the Milwaukee River.
A lip tumor diagnosed as a papilloma on a white sucker (Catostomus commersonii) collected from the Milwaukee River.
![Dairy cows in an animal feeding operation in New York](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/cows_in_ny_cafo2_l.jpg?itok=Kve8qzNq)
Dairy cows in an animal feeding operation in New York
Dairy cows in an animal feeding operation in New York
Remnants of a spruce forest complex following a severe wildfire in the Yukon Flats National Wildlife Refuge, Alaska. Wildfires are the dominant landscape-scale disturbance operating at annual time scales in Alaska, and fires play a major role in the rate and extent of vegetation growth and productivity of a site.
Remnants of a spruce forest complex following a severe wildfire in the Yukon Flats National Wildlife Refuge, Alaska. Wildfires are the dominant landscape-scale disturbance operating at annual time scales in Alaska, and fires play a major role in the rate and extent of vegetation growth and productivity of a site.
![Cedar Creek in Congaree National Park, SC, showing old growth bottomland hardwood forest](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/nps_steven_mcnamara_cedar_creek_l.jpg?itok=cvyHavHL)
Cedar Creek in Congaree National Park, SC, showing old growth bottomland hardwood forest
Cedar Creek in Congaree National Park, SC, showing old growth bottomland hardwood forest
Photograph showing white-faced ibis nesting at Bear River Migratory Bird Refuge, Great Salt Lake, Utah. U.S.
Photograph showing white-faced ibis nesting at Bear River Migratory Bird Refuge, Great Salt Lake, Utah. U.S.
![USGS scientists measured the concentrations of select endocrine disrupting chemicals (EDCs) in Spirit Creek, Georgia](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/spirit_creek_sc_p5180029_l.jpg?itok=23NqMIij)
USGS scientists measured the concentrations of select endocrine disrupting chemicals (EDCs) in Spirit Creek, Georgia, as part of an assessment of the effects of the closure of a wastewater treatment plant. Sprit Creek is typical of a stream in coastal environments.
USGS scientists measured the concentrations of select endocrine disrupting chemicals (EDCs) in Spirit Creek, Georgia, as part of an assessment of the effects of the closure of a wastewater treatment plant. Sprit Creek is typical of a stream in coastal environments.
U.S. Geological Survey (USGS) hydrologist making field notes during winter water quality sampling from a stream in north central Iowa.
U.S. Geological Survey (USGS) hydrologist making field notes during winter water quality sampling from a stream in north central Iowa.
![Freshwater snail (Lymnaea stagnalis) used in the laboratory exposure tests to understand metal uptake and bioavailability](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/ctt_croteau_the_pond_snail_lymnaea_stagnalis_full_l.jpg?itok=53Oi2C69)
Picture of the freshwater snail (Lymnaea stagnalis) used in the laboratory exposure tests to understand metal uptake and bioavailability.
Picture of the freshwater snail (Lymnaea stagnalis) used in the laboratory exposure tests to understand metal uptake and bioavailability.
![Highest stream mycotoxin concentrations were observed during spring snowmelt conditions in agricultural settings](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/mycotoxins_blairs_3_10_026_crop_l.jpg?itok=ZmejZIjW)
Highest stream mycotoxin concentrations were observed during spring snowmelt conditions in agricultural settings such as pictured in this Iowa stream.
Highest stream mycotoxin concentrations were observed during spring snowmelt conditions in agricultural settings such as pictured in this Iowa stream.
![The mayfly (Cinygmula) is one of the insects scientists use to study the bioaccumulation of dissolved and dietary metals.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/ctt_croteau_mayfly_cinygmula_crop_l_0.jpg?itok=8-M_oH-X)
The mayfly (Cinygmula) is one of the insects scientists use to study the bioaccumulation of dissolved and dietary metals.
The mayfly (Cinygmula) is one of the insects scientists use to study the bioaccumulation of dissolved and dietary metals.
![Three images showing 1) hands working on lab equipment, 2) a woman handling test tubes in a bag and 3) glass flasks in a lab.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/LabAnalytical-MicrobiaBiogeochem.png?itok=GbFFJPbA)
Left: Distillation rig used in the measurement of microbial sulfate reduction rates associated with a method based on the incubation of sediment samples with radioactively labeled sulfate. Photographer: M. Marvin-DiPasquale. Date: 3/5/2001.
Left: Distillation rig used in the measurement of microbial sulfate reduction rates associated with a method based on the incubation of sediment samples with radioactively labeled sulfate. Photographer: M. Marvin-DiPasquale. Date: 3/5/2001.
![USGS hydrographers collecting a water-quality sample at the Zumbro River near Rochester, Minnesota](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/rochester_09222009_us_jdl_aam_2_l.jpg?itok=R8BSFvzK)
USGS hydrographers collecting a water-quality sample at the Zumbro River near Rochester, Minnesota
USGS hydrographers collecting a water-quality sample at the Zumbro River near Rochester, Minnesota
![Image: Testing Coal-Tar Sealcoats for Toxic PAH Emissions](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/ParkingLot153-1.jpg?itok=kOfSDYpY)
A professional applicator applies coal-tar-based sealcoat to a test plot used to measure emission of polycyclic aromatic carbons (PAHs) into the air.
A professional applicator applies coal-tar-based sealcoat to a test plot used to measure emission of polycyclic aromatic carbons (PAHs) into the air.
The team of USGS scientists collected stream water samples before and after rainfall events for this study. In this photo a USGS scientist is taking measurements of field parameters (dissolved oxygen, water temperature, specific conductance, and pH) from New York Branch, Iowa, at low flow (baseflow) conditions.
The team of USGS scientists collected stream water samples before and after rainfall events for this study. In this photo a USGS scientist is taking measurements of field parameters (dissolved oxygen, water temperature, specific conductance, and pH) from New York Branch, Iowa, at low flow (baseflow) conditions.
![View of stream water following a manure spill, which has strongly discolored the water.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/sm_spill_discolored_stream_dsc01391_l.jpg?itok=SK2uy7Xo)
View of stream water following a manure spill, which has strongly discolored the water.
View of stream water following a manure spill, which has strongly discolored the water.
![Upper workings of the Pennsylvania Mine in the headwaters of Peru Creek, Colorado](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/pennsylvania_mine_peru_creek_co_rlr_img_0010_l.jpg?itok=NhJwjBZ7)
Upper workings of the Pennsylvania Mine in the headwaters of Peru Creek, Colorado.
Upper workings of the Pennsylvania Mine in the headwaters of Peru Creek, Colorado.
Mountain Sheep Spring, Arizona, is one of the 37 springs north of the Grand Canyon near areas of breccia-pipe uranium mining that U.S. Geological Survey (USGS) scientists studied.
Mountain Sheep Spring, Arizona, is one of the 37 springs north of the Grand Canyon near areas of breccia-pipe uranium mining that U.S. Geological Survey (USGS) scientists studied.
This cyanobacterium has radiating filaments and basal heterocysts. Green is Sytox Green (a DNA stain that is excluded from live cells).
This cyanobacterium has radiating filaments and basal heterocysts. Green is Sytox Green (a DNA stain that is excluded from live cells).
Schmutz Spring, Arizona, is one of the 37 springs north of the Grand Canyon near areas of breccia-pipe uranium mining that U.S. Geological Survey (USGS) scientists studied.
Schmutz Spring, Arizona, is one of the 37 springs north of the Grand Canyon near areas of breccia-pipe uranium mining that U.S. Geological Survey (USGS) scientists studied.