GeoHEALTH-USGS Newsletter, April 2021
The GeoHEALTH–USGS Newsletter—published since 2004—provides information on USGS science pertinent to safeguarding the health of fish, wildlife, domesticated animals, livestock, and people from environmental exposures to contaminants and pathogens, featuring research from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
Dragonfly Larvae are Effective Bioindicators of Mercury Exposure in Fish and Amphibians—Results of Citizen Science in 100 National Parks and Protected Places
Mercury concentrations were measured in dragonfly larvae across more than 450 sites in 100 national parks and protected places as part of a partnership among Federal agencies, academic researchers, and more than 4,000 citizen scientists. Mercury concentrations in dragonfly larvae were positively correlated with mercury concentrations in fish and amphibians living in the same aquatic environments, thus providing a tool to predict mercury exposure in other wildlife. This study also provides a framework for engaging citizen science as a component of research and monitoring programs.
Framework Developed to Evaluate the Practicality of Effects-Directed Analyses to Identify Endocrine Active Chemicals in Complex Environmental Sample Mixtures
An effects-directed analyses (EDA) framework for endocrine active chemicals was developed to help decision makers quickly evaluate the efficacy and practicality of an EDA approach in waste and surface waters and how adjustments could be made to increase its success.
Clothianidin Exposure Associated with Changes in Tadpole Behavior
During a laboratory exposure study, tadpole movement decreased with increased concentrations of clothianidin, a neonicotinoid pesticide. Decreased movement could affect a tadpole’s ability to forage, escape predation, and metamorphose before ponds dry.
Wetland Management Technique Designed to Reduce Mercury in Water and Fish Tested During a Short-Term Field Study
Results from a 3-year study indicate there was support for the use of open- and deep-water treatment pools at the downstream end of seasonal wetlands to reduce methylmercury concentrations in water exported from the wetlands, but the treatment had no measurable effect on wetland fish. Questions remain about the long-term potential for mercury removal using this wetland management strategy.
Bird Hatchling Development Following Exposure to Environmentally Relevant Levels of Brominated Flame Retardants
Scientists performed laboratory studies with American kestrels and zebra finch to determine the effects of brominated flame retardant exposure on hatchlings. They found evidence that exposure while in the egg disrupted thyroid function in female American kestrel hatchlings and affected nestling body condition in zebra finch hatchlings, but no other effects were detected.
New Virus Identified in Melanistic Skin Lesions on Smallmouth Bass from the Chesapeake Bay Watershed
Scientists determined the risk factors associated with smallmouth bass melanistic skin lesions on smallmouth bass in the Susquehanna and Potomac Rivers, in the Chesapeake Bay watershed. A new virus, which appears to be a member of an emerging viral family, the Adomaviridae, was identified in the lesions. Questions remain about the full characterization of the virus and the role of environmental factors, such as temperature and chemical contaminants, in initiation, progression, and health effects of the lesions.
Mercury Accumulation in Waterbirds (Black Rails) Related to Sediment Chemistry in San Francisco Bay Wetlands
The U.S. Geological Survey (USGS) assessed the effect of sediment chemistry, food web structure, and diet on mercury bioaccumulation in black rails in the San Francisco Bay watershed. Differences in mercury accumulation in the birds were related to differences in sediment chemistry in the wetlands.
Review of Cyanobacterial Neurotoxins—Information for Prioritizing Future Science Directions
The current state of knowledge on the modes of action, production, fate, and occurrence of the freshwater cyanobacterial neurotoxins, anatoxin-a and saxitoxin, was reviewed and synthesized to identify gaps and critical research needs to better understand the health effects of algal toxins.
U.S. Geological Survey Research Scientist Recognized for Advancing Exposure Science
U.S. Geological Survey (USGS) Scientist Dana Kolpin was presented the International Environmental Award by Reciphram celebrating his research on the occurrence, sources, fate, and effects of environmental contaminants such as pharmaceuticals and pesticides.
Bioaccumulation of Mercury in Fish Varied by Species and Location in the Chesapeake Bay Watershed—Summary of Existing Data and a Roadmap for Integrated Monitoring
Fish mercury data from State monitoring programs and research studies within the Chesapeake Bay were compiled and summarized to provide a comprehensive overview of the variation in fish mercury concentrations among species and habitats within the watershed. These data are put into context with existing health benchmarks for humans, birds, and fish. Scientists also provide a roadmap for an integrated monitoring program.
Technique Used to Distinguish Natural Background from Human-Caused Enrichment of Trace Elements in Soils
Human activities can enrich toxic trace elements like uranium and arsenic in the environment, but these elements also are from natural sources and occur at background levels. Scientists utilized a technique that identifies the background and the elemental fingerprint of human-caused enrichment and tested the new technique on data collected near uranium mines in Arizona.