Exposure Pathways
Exposure Pathways
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Framework for Examining Stream Ecosystem Health in Areas of Shale Gas Development—A Multi-Parameter Watershed-Based Case Study in Pennsylvania
In a case study of 25 headwater streams in Pennsylvania, no statistically significant associations were determined between shale gas development and geochemical tracers of produced waters or measures of microbial and macroinvertebrate community composition. Although the results are specific to the region studied, the integrated biological and geochemical framework provides a tool for examining...
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...
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 use of mercury isotope measurements in fish tissue allow for distinguishing different sources of mercury that are bioaccumulating into the food web. Mercury isotope signatures in fish in forested...
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...
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...
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 adverse effects...
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.
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.
Can There be Unintended Benefits when Wastewater Treatment Infrastructure is Upgraded?
Science from the U.S. Geological Survey (USGS) and other entities has shown that a mixture of natural and synthetic estrogens and other similar chemicals are discharged from wastewater treatment plants (WWTPs) to streams and rivers.
Food Resources Lifecycle Integrated Science Team
The team studies the movement of toxicants and pathogens that could originate from the growing, raising, and processing/manufacturing of plant and animal products through the environment where exposure can occur. This information is used to understand if there are adverse effects upon exposure and to develop decision tools to protect health.
Minerals Science Team
The Minerals Integrated Science Team focuses on contaminant exposures in the environment that might originate from mineral resource activities including, transportation, storage, extraction and waste management. Perceived health risks to humans and other organisms will be distinguished from actual risks, if any. If actual risks are identified the science produced by this team can inform how to...
Unique Methods Used to Understand Frog Exposure to Pesticides in Agricultural Settings
Adult frog exposure to pesticides in aquatic and terrestrial habitats was quantified using a novel combination of radio telemetry and passive sampling techniques to better understand factors affecting frog health and survival in agricultural landscapes.