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November 8, 2016

Studies on the aquatic food web, tree swallows, and the spread of contaminants take center stage at SETAC 2016.

The health of the environment is a research priority for the U.S. Geological Survey, and some of the recent highlights of that research will be on display at the Society of Environmental Toxicology and Chemistry’s 2016 North American conference this Fall. For reporters interested in attending these presentations at the conference, or for following up with the scientists who did the research, please call or email Alex Demas at 703-648-4421 or

Maintaining the Aquatic Food Web

The largest subject area that USGS will have presentations and posters in is studies on the health of aquatic organisms, such as aquatic invertebrates. Although not as charismatic, aquatic invertebrates serve an essential function in the food web, and are often on the front lines of exposure to contaminants.

Some of those contaminants come from mine waste or drainage. Often these are metals, and they can have significant toxic effects on aquatic invertebrates. USGS is presenting studies that look at the effects of these metals on caged and wild crayfish, mussels, aquatic insects like caddisflies, and amphipods, which are tiny invertebrates that are an important food source for many other animals.

When one part of the food web is affected, it can ripple throughout the entire ecosystem. Thus, studies of the entire food web are important to show the true effects a contaminant can have. In one such example, USGS is presenting a study on how the insecticide bifenthrin can have significant impacts on aquatic food webs and even affect nearby land-based food webs.

Moving up the food web, USGS has studies on frog species’ exposure to the neonicotinoid insecticides clothianidin and thiamethoxam, as well as a study on the effects of the herbicide atrazine on fathead minnows. Although each of these species is not the target of the pesticide in question, they can still be affected, either through bioaccumulation in the food the species eat or exposure in the environment.

In the same vein of unintended consequences, natural disasters can have longer-reaching effects than the initial destruction they’re known for. USGS will be presenting studies on organic pollutants spread by Hurricane Sandy and their effects on bluefish and resident mussels.

And finally, USGS plays an important role in the methodologies that go into studying the health of aquatic organisms. Strategies to address endocrine disruption in Chesapeake Bay fish and wildlife; the chronic toxicity of various chemicals to freshwater mussels; and the role of mesocosms in studying aquatic life are three presentations that USGS has on environmental health methodology.

The Science of Spills in Streams

In addition to studying the organisms that live in aquatic environments, USGS studies the health of the aquatic environments themselves. For instance, in addition to studying the actual effects of pesticides on aquatic organisms, USGS scientists study how the pesticides can reach the aquatic organisms in the first place.

This year, USGS has presentations on how an additive to the popular pesticide glyphosate can spread in the environment; what the effects of various pesticide mixtures are in Midwestern streams; and what levels of neonicotinoid insecticides are in certain agricultural and urban streams throughout the United States.

In addition, USGS looks at unintended spills of various chemicals, with presentations on diluted bitumen spills in the Kalamazoo River and the residual toxicity of NaOH-based ballast water treatment system for freshwater bulk freighters. Also, USGS has a presentation on what can happen to sediment toxicity during a dam’s removal.

Finally, just as with the aquatic organisms, USGS has valuable studies on how to research the health of aquatic environments. In addition to the well-established EPA MDL procedure, USGS examines how to estimate detection levels for multi-analyte methods, which is important for determining contaminant levels in streams. Also, USGS has taken a look at the use of the tool ToxCast to evaluate organic contaminant effects in Great Lakes Tributaries and whether or not reducing the amount of sulfate can mitigate the production of methylmercury in the Great Lakes.

Taking to the Sky

Aquatic organisms aren’t the only ones USGS studies. This year, there are a number of papers and posters that look at the health of birds, namely what chemicals and contaminants they’re exposed to and the effects they may experience.

Tree swallows received the most attention, with USGS and EPA looking at the distribution and effects of legacy contaminants on egg and nestling survival in Great Lakes Areas of Concern, as well as whether the swallows are appropriate bioindicators for other toxicants. In addition, they were also used to assess how effective various remedies were in those Areas of Concern.

Birds of prey were also studied, because their position at the higher end of the foodweb means they can be exposed to significant bioaccumulation of various contaminants. However, USGS research on ospreys showed that, at least in the Chesapeake and Delaware Bays, they largely have a clean bill of health.  Two other studies looked at American kestrels and what happens when they are exposed to persistent organic pollutants or priority flame retardants while developing in eggs.

The Science of Environmental Chemistry

Finally, USGS has several presentations about the science of environmental chemistry, including one on environmental chemistry perspectives from around the world. And, before the conference officially begins, USGS is giving a workshop on exploratory data analysis and plotting data with ggplot2 in R.

The Society of Environmental Toxicology and Chemistry’s 2016 North American conference runs from November 6-10 in Orlando, Fla.

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