Contaminant Biology Program

Featured Science Activities

Our science activities are summarized in a series of feature articles that highlight recent U.S. Geological Survey (USGS) environmental health science activities. They are short summaries of peer-reviewed journal articles and USGS reports co-authored by our specialized teams of scientists.
Older featured science activities are on our old Web site.

Filter Total Items: 53
Date published: November 20, 2019
Status: Completed

Refined Model Provides a Screening Tool to Understand Exposure to Contaminants from Incidental Wastewater Reuse

Refinement of the existing national-scale “de facto reuse incidence in our nation’s consumable supply” (DRINCS) model, complemented by field measurements, provides a screening tool to understand human and wildlife exposure to toxicants and pathogens associated with the incidental reuse of treated wastewater in the Shenandoah River watershed. The model results can be accessed in a companion...

Date published: November 18, 2019
Status: Completed

Prevalence of Malignant Melanoma in Brown Bullhead from Lake Memphremagog Greater than Expected—Linkages to Contaminant Exposure and Implications for Fish Population Health are Currently Unknown

Raised black lesions observed in 30 percent of the brown bullhead collected from two sites in Lake Memphremagog from 2014 through 2017 were identified microscopically as malignant melanoma. Malignant melanoma in freshwater fishes has been reported before, but this cancer occurrence cluster is raising questions about the cause of the tumors and the implications for the long-term health of fish...

Contacts: Vicki Blazer
Date published: November 13, 2019
Status: Completed

Food Web Changes Dampen Expected Reductions in Lake Trout Mercury Levels in Lake Michigan—Invasive Species Play Major Role

Combined analyses of mercury, nitrogen, and carbon isotopes in archived lake trout (Salvelinus namaycush) tissues and sediment cores in Lake Michigan from 1978 to 2012 indicated that lake trout mercury concentrations mirrored declines in mercury sources prior to the arrival of invasive species that changed mercury transfer through the food and dampened the expected decreases in mercury...

Date published: October 11, 2019
Status: Completed

Mercury Isotope Ratios used to Determine Sources of Mercury to Fish in Northeast U.S. Streams

Mercury isotope analyses were used to distinguish different sources of mercury to fish in 23 streams along a forested-rural to urban-industrial land-use gradient in the Northeastern United States – the first time biological tissues have been used to map mercury sources across a geographic region. The use of mercury isotope measurements in fish tissue allow for distinguishing different sources...

Date published: October 4, 2019
Status: Completed

Science to Help Understand Exposure and Toxicological Effects of Environmental Mercury to Representative Birds

Exposure and toxicity of environmental mercury to birds can be enhanced or lessened due to the available sources and forms of mercury and other species dependent factors such as life stage, migratory patterns, foraging and nesting behaviors, transfer of mercury from mothers to eggs, and sex. For example, mercury exposure can lead to sublethal toxicological effects that can influence parental...

Contacts: Josh T Ackerman
Date published: October 3, 2019
Status: Completed

Intersex in Male Smallmouth Bass in the Missisquoi River in Vermont: Understanding Factors that Can Lead to Endocrine Disruption in Field Settings

The presence of testicular oocytes (intersex) in male smallmouth bass (Micropterus dolomieu) in the Missisquoi River in Vermont varied over the period of the study and was not related to concentrations of known endocrine disrupting chemicals in the River. Although previous studies have shown linkages between endocrine disrupting chemical exposures and intersex in fish, these results...

Date published: October 2, 2019
Status: Completed

Amphibians Exposed to Oil and Gas Co-Produced Wastewaters: Differentiating the Actual and the Perceived Inorganic Contaminant Hazards — Prairie Pothole Region

Chloride and metals in oil and gas co-produced wastewaters (often referred to as brines) are commonly perceived as contaminant hazards for biota. Amphibian abundance in the Prairie Pothole Region affected by historic oil and gas co-produced wastewaters was lower in wetlands with high concentrations of chloride indicating an actual contaminant hazard. Metals detected in sediments and amphibian...

Contacts: Kelly Smalling
Date published: October 1, 2019
Status: Completed

No Adverse Reproductive Effects Observed in Tree Swallows Exposed to Perfluoroalkyl Substances in Clarks Marsh, Michigan

Perfluoroalkyl substance (PFAS) concentrations in tree swallows (Tachycineta bicolor) breeding at Clarks Marsh near a decommissioned U.S. Air Force base in Michigan were among the highest concentrations ever documented in birds indicating significant PFAS exposures.   In contrast to previous studies where reproductive impairment was documented at lower PFAS exposure, there were no...

Date published: May 7, 2019
Status: Active

Sublethal Effects of Contaminants in Aquatic Food Webs—Research Challenges and Considerations for Future Studies

U.S. Geological Survey (USGS) and academic scientists partnered to identify challenges and provide considerations for future scientific study designs to advance our understanding of the often subtle sublethal effects of contaminants on individuals, populations, communities, and entire aquatic food webs. 

Contacts: Kelly Smalling
Date published: April 22, 2019
Status: Active

No Evidence of Toxicity to Birds Ingesting Neonicotinoid-Coated Wheat Seeds During Controlled Laboratory Study

Scientists determined what happens to the neonicotinoid insecticide, imidacloprid, on coated wheat seeds once ingested by Japanese quail (Coturnix japonica)—a model species for free-range, seed-eating, upland game birds. Imidacloprid was found to be rapidly adsorbed, metabolized, and excreted, and resulted in no overt signs of toxicity during a controlled laboratory study.

Date published: February 25, 2019
Status: Completed

Uranium in Springs Sampled Near the Grand Canyon Likely from Natural Sources

Scientists measured nine naturally occurring elements including uranium at 37 spring sites in the Grand Canyon area to establish baseline conditions and to understand the sources of uranium to local springs. Scientists found relatively greater concentrations of uranium at 6 of the 37 springs. A comprehensive geochemical analysis coupled with an understanding of the flow patterns in the area...

Date published: February 25, 2019
Status: Completed

Roadmap to Understanding Factors Influencing Mercury Exposure and Adverse Health Effects

In a comprehensive overview, scientists explain that human and wildlife exposure and toxicological responses to mercury are dependent on factors that operate across global, individual, and molecular scales. They provide a roadmap for unified research to facilitate a better understanding of human and wildlife health risks from mercury exposure.