Home Archived February 2, 2018

Emerging Contaminants




Today on the USGS CoreCast we explore what impact emerging contaminants have on the health and development of aquatic wildlife. We traveled to the Pacific Northwest to talk with a multidisciplinary research team of USGS scientists about an ongoing study that characterizes the contaminants and habitats for a number of aquatic species along the lower Columbia River.


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[Steven Sobieszczyk]

Good or bad, you know an issue has infiltrated the public consciousness when it has been satired in the Sunday paper. However, chemicals, pharmaceuticals, and pollutants in our rivers are no laughing matter.


Hello and welcome. I’m Steven Sobieszczyk. In today’s episode of the USGS CoreCast we’re exploring what impact water pollution has on the health and the development of aquatic wildlife. Since the 1990s there have been numerous studies around the country that have been investigating how a wide range of chemical compounds, industrial pollutants, and human by-products have made it into our Nation’s waterways. Traditionally, most people were not overly concerned about this because the old mantra used to be “dilution is the solution to pollution.” However, this is far from true. In fact, recent studies have shown a much starker reality. After the contaminants make it into the rivers and streams, tests now show that there are measurable quantities of these contaminants within the water, itself, as well as in the under-water sediments, the nearby aquatic insects, migratory fish that were eating these insects, and even predatory wildlife that consume all these different organisms.


In the last few years the USGS has increased its efforts to monitor these emerging contaminants in lakes and rivers around the United States, including the Potomac, Mississippi, Colorado, and Columbia Rivers. To explore, in more detail, one example of what impact these contaminants are having in our nearby streams, we traveled to the Pacific Northwest to talk with a team of USGS scientists about an ongoing study that characterizes the contaminants and habitats for a number of aquatic species along the lower Columbia River. This contaminant and habitat study, or ConHab for short, is a multidisciplinary research project composed of 12 USGS scientists from 7 different states, including Oregon, Washington, California, Colorado, Missouri, Texas, and Louisiana. Using their unique expertise in chemistry, biology, geology, and hydrology, these researchers have been exploring emerging contaminants, such as flame-retardants, pharmaceuticals, personal care products, and industrial chemicals in the Columbia River.


[Elena Nilsen] What we refer to as emerging contaminants can mean many different kinds of chemicals. To understand what these chemicals are we just need to think about our urban lifestyle. And we know that we use products everyday that have chemicals in them, and that they end up going through wastewater treatment plants because plants weren’t designed to take these chemicals out. And they eventually end up in the rivers. Similarly, industrial processes that have their own treatment process probably don’t remove all these chemicals. So there are various ways that these chemicals get into the environment, but we know they are getting into the environment and we’re concerned about the effects they might be having on organisms that live in the Columbia River.


[Steven Sobieszczyk] In order to effectively assess the impact of chemical pollutants in an environmental setting there must be a clear objective for the investigation. The approach used by investigators in this study focused on 3 sites that represented a gradation of contamination, with a focus on how this contamination affected a number of species within a predefined food web.


[Elena Nilsen] So at the ConHab study sites, we’re sampling several levels of the food web to try and answer this question of “are the chemicals there and are they moving from one organism to another?” We’re using passive samplers to try to tell us what the chemical concentrations are in the water; we’re collecting sediments; we’re collecting invertebrate biomass, or the bugs that live on the bottom of the river; we’re collecting largescale suckers as a resident fish; and we collecting osprey eggs, a bird of prey that eats the largescale sucker.


[Jennifer Morace] So many of the newer emerging compounds we don’t have great toxicity information for, so it’s hard for us to know at “x” concentration this will happen to a biode or to a fish. So that wass part of why we decided to do a foodweb study to try and look at if we’re seeing these concentrations in the river, what does this mean for the fish? Can we tell if with the biomarkers…that helps us tell if there are effects we’re seeing in the fish and trying to tie those back to the contaminant concentrations. Then, likewise, trying to see what effects it might be having on the osprey and other portions of the foodweb.


[Steven Sobieszczyk] With the ConHab study finishing up, results demonstrating how emerging contaminants impact aquatic wildlife prove very interesting.


[Elena Nilsen] As far as the concentrations of contaminants in the fish at the three sites, we looked also not just at whole fish, but we looked at five different tissues. We looked at brains, gonads, stomachs, fillets, and livers. And the concentrations in the livers were higher at all the sites than the other tissues that we looked at. This makes sense if you think of the liver as filtering out the toxins of the fish’s body. Preliminary results do indicate that we’re seeing a difference in some of the biomarkers between the sites, as well. For instance, the gonadal somatic index, or the ratio of gonad size to the mass of the organism. And some of the sperm viability and motility studies are showing lower sperm motility and viability at the sites with higher concentrations of contaminants.


[Steven Sobieszczyk] Since most of the data for this project was collected at three sites, finding a way to project, or extrapolate, this data across the length of the Columbia River was nearly as important as the data collection, itself.


[Elena Nilsen] As part of the project we have done some sediment transport modeling. This is an important part of the project because our thought is that a lot of these emerging contaminants are going to be associated with suspended sediments in the river. You can think of them as being very sticky. So they stick to the sediments and move throughout the systems on the sediments. So, by modeling the transport of the sediments we get an idea of the distribution of these contaminants throughout the larger system.


[Animation 1 - Streamflow]


[Elena Nilsen] In this video we can see the flow changing direction and changing velocity, with the higher velocities in red and lower in blue. This changes with tidal cycle. The higher velocities, obviously, will transport the heavier sediment and transport more sediment, overall. In the lower velocities is where we expect some of the sediment to start falling out and be distributed on the bed.


[Animation 2 – Point-Source Tracer]


[Elena Nilsen] So in this video we’re showing the foodweb area that’s near the urbanized corridor near Portland, where the Willamette River comes in. What this is is showing a tracer input, it’s approximating if a contaminant were introduced into the river how the dispersal of the contaminant, with fine-grained sediments would be different at those different locations given the different flow forcing, tidal influence versus the higher flow. In the top panel, we’re showing base flow, highlighting the tidal influence, and in the lower panel we’re showing the experimented high flow.


[Elena Nilsen] So some of these results are similar to what we’re seeing in some of the other studies done in, for instance, Lake Mead or Potomac. What’s different is in some of those studies we’re seeing higher concentrations and maybe more obvious biological changes in the fish, but what’s different here is we’re trying to piece together how the fish fit into the foodweb as a whole.


[Jennifer Morace] If we could combine these types of foodweb studies with source identification then we could try to tie contaminants to effects. And then also look for where the sources of these contaminants are to work toward reduction to try and improve conditions in the ecosystem. Because the Columbia River is a beautiful river, the Pacific Northwest is a great place, it’s very culturally important and we want to preserve that. And sometimes when people look at the river now and the great setting that we have it’s hard for them to image that there are problems in this ecosystem. But we know there are hints at some of these problems that may be arising and we want to stop that before we get to that type of condition that leads us to where…some of the issues that like Chesapeake Bay or Lake Mead are trying to deal with. We want to try and preserve our way of life here.


[Steven Sobieszczyk] If you want to learn more about the ConHab project or emerging contaminants, as a whole, check out the links in our show transcripts, which you can find at the CoreCast website at usgs.gov/corecast. If you want to see what else is going on in the Pacific Northwest, you can also check out the local podcast, the USGS Oregon Science Podcast at or.usgs.gov/podcasts. If you want to follow USGS daily, you can also go to our USGS social media website at usgs.gov/socialmedia. There you can follow the USGS on Facebook, Twitter, YouTube, and even Flickr.


Until next time. I’m Steven Sobieszczyk.


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This podcast is a product of the U.S. Geological Survey, Department of the Interior.


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