Earth & Sky

The following person was interviewed for today’s program. Our thanks to:

Tracy Collier, Ph.D.
Program Manager
Ecotoxicology and Environmental Fish Health Program
Northwest Fisheries Science Center
Seattle, WA

Interview with Dr. Collier:

ES:

TC: Historically, we’ve looked at what we call legacy pollutants, and point sources ? things like PCBs, polychlorinated biphenyls, and aromatic hydrocarbon ? or PAHS ? polycyclic aromatic hydrocarbons, and we’ve found a number of effects on the biota of Puget Sound, focusing mostly on fish as our sentinel species. And things like cancer, reproductive dysfunction, these things have been known about for some time. Other people have reported them as well. Puget sound is probably one of the best-studied ecosystems for looking at the effects of these sorts of contaminants in aquatic waters, in aquatic ecosystems. And, more recently we’ve branched out from what we call the legacy pollutants, to things that are defined more as non-point source pollutants, or non-point source contamination. Things like – and these get a little bit of a mouthful to say ? PBDEs, the polybrominated diphenyl ethers ? commonly used flame retardants put into a lot of materials ? computers, upholstery, cushions, foam, that sort of thing, to reduce fires in houses and save lives. But what’s happening is that these compounds like the PBDEs are turning up in the ecosystems, and turning up in Puget Sound as well, in a variety of animals, all the way from the invertebrates, fish, up to the orca whales ? the killer whales ? that inhabit Puget Sound. So, these types of compounds, which were believed to be fairly non-persistent, are turning out to be environmentally more persistent than people believed when they were approved for use as flame-retardants. So what’s happening is that these are showing up more and more in the biota. People are getting increasingly concerned that these are a diffuse source of contamination they come from all sorts of sources ? from all sorts of urban run-off, dust in the air, etc? So they get very hard to control. What we found with the polychlorinated biphenyls and the PAHs is, especially with things like the PCBs, which are resistant to being metabolized, we can clean up the sources, we can dig up dirty sediments, we can shut off sources at point-source discharges if that’s possible, but what looks like what’s happening is that some of these PCBs are actually cycling through the ecosystem, or cycling through the biota. So there may be, essentially this very long-lived reservoir of PCBs in the ecosystem, that no matter what we do we won’t be able to remove. It’ll just take an awful lot of time. So when we have other compounds that are even more difficult to control with their sources, like these flame-retardants, the issue is, how do we keep them out of the ecosystem to start with? Because, I think that most people that have studied aquatic toxicology, environmental toxicology for a long time have come to the conclusion that it is far, far better to stop these things from getting into the ecosystem as compared to trying to clean them up later on.

ES:

TC: Basically, what that means is that as these compounds are taken up by the biota, generally in plankton, invertebrates eaten up by fish, fish eat other fish, they bioacculmulate, or biomagnify in the food chain, until they get into the higher level vertebrates, the higher level predators such as the salmon, the killer whales, etc. And, that’s in their bodies and it builds up. But then they die in the ecosystem. They then, their bodies then become an ongoing source of these contaminants to the invertebrates, to the microbes, etc… Basically, they’re just cycling through with the energy flow. These compounds accumulate with fat, and that’s obviously a prime source of nutrients for a lot of different animals. So what happens is, as that fat is consumed by different animals, the contaminants go with it. They basically follow the biology.

ES:

TC: Of course, we don’t generally put our people back into the ecosystem, I guess we either cremate them or bury them into the cemeteries. We are part of the ecosystem, from the standpoint that humans accumulate these contaminants in their bodies, but they’re not part of that recycling issue.

ES:

TC: I’m concerned about it. I’ve been studying aquatic toxicology issues now for over 30 years, and increasingly, I’m feeling that some of the things that we’re seeing in our ecosystems are actually due to these contaminants that are getting into our ecosystem everyday. And a lot of these are diffuse contaminants, these non-point source contaminants. And a lot of these studies we’re doing here area looking at the effects of very low levels of pesticides on fish behaviors, and finding that actually, at environmentally relevant levels of pesticides in water, fish behavior is altered substantially. It’s really a problem for a salmon, which have very complex life histories. They have to go through their normal suite of behaviors in order to spawn, to reproduce, to imprint on their home stream, to return to their home stream to spawn. So these effects on behavior are actually fairly major.

ES:

TC: One of the major impacts that these pesticides have – many pesticides are designed to be neurotoxic. They kill insects and pests by interfering with their nervous system. And the salmon’s nose….

ES:

TC: Well, it’s kind of an interesting story. The history of this lab, which a little over 30 years ago when I started as an undergraduate, basically was a bunch of people working on fish oils – trying to extract fish oils, characterize them, because people were aware that fish oils were very nutritious, and had some positive benefits for human health. As they were extracting these fish oils to look at them, they started finding these strange peaks in their chromatograms, the chemical analysis of the oils. And these peaks turned out to be these PCBs, these polychlorinated biphenyls, which were used because they were thought to be biologically inert, they were very good flame retardants – they were used a lot as insulators, insulating foods. So some people in that lab started breaking off to try to understand where these PCBs were coming from. And, at the same time, people were reporting PCBs distributed worldwide through different parts f the ecosystem. So, basically out of this fat chemistry approach, people started finding these fat soluble contaminants. And then they branched off and started looking at effects. That was all in the early to mid 70s. Probably, it was more in the 1980s, mid 1980s, when people started getting more and more concerned about non-point source pollution, about stream runoff, airborne deposition. And it’s just a much more difficult beast to tackle, toxicologically, because there are so many contaminants, there are so many sources. So we have focused in our lab at looking at animals in their natural ecosystem, on doing a lot of field studies as opposed to focusing so much on laboratory studies, which is what toxicology used to be all about. Now we’re going out to the field, and trying to understand how the animals are behaving and surviving, what they’re exposed to, in trying to make those linkages between exposure and effects.

ES:

TC: We’ve got a 45-foot research boat that we use, here in Puget Sound. And, depending on the program, depending on the project, our boat is usually out in the field on average two days a week. And if we’re working on bottom fish, we trawl the bottom with a small, scientific fishing net. We capture the fish; we usually dissect them, and look for chemical accumulations in their body. We look for biomarkers of chemical exposure. And also, we assess biological function. How well they’re reproducing, how well they’re growing, that sort of thing. Sometimes, we just tag the fish. Recently we’ve started using different tags, different sonic tags, so that we can actually track these fish. We catch them and release them back into the environment. And then we track them for up to a year and a half, to try and understand where they go and what habitats they use, to try and get a better handle as to what sorts of contaminant exposure they may be experiencing. If we’re working on salmon, on juvenile salmon, then we’ll use beach stains, or mid-water tows to try to understand, not only contaminant exposure, but there’s a great deal of effort going on here at the center, looking at how salmon use near-shore habitats. Because that’s really a mystery in their life cycle. How they use them, how long they use them, how important those habitats are. It’s a pretty complex scientific undertaking here at the lab, so it’s hard to encapsulate it all into one mouthful.

ES:

TC: So the compounds like the PCBs and the PBDEs are turning out to have a wide range of biological effects. One of the major effects they have is an alteration of the immune system, and reduced disease resistance in animals that are exposed to them. They cause things like reduced growth, the animals are unable to convert nutrients into energy and don’t grow as well. The PBDEs, one of the causes for concern for those is their similarity to, what we call thyroxin-like hormones and the influences on a lot of developmental processes. So there’s a lot of concern for embryo and larval development in animals exposed to PBDEs. These PBDEs in rodent studies are turning out to show deficits in cognitive function, or learning behavior. Animals don’t appear to learn as well when they’ve been exposed to PBDE. And that’s obviously of concern to humans as well, ecological concerns.

ES:

TC: We can, right. We have behavioral assays in what we call cognitive function assays that we can do in fish. And we’re just starting those studies here on the PBDEs. We’re going to be bringing in a post-doc pretty soon to work across a couple of different divisions here at the Center to look at this issue of PBDEs and their impacts on the early life history and early developmental processes in fish. Because it is a cause for concern, that these compounds are out there, and we really don’t know the biological effects, yet they’re there. We have to get some information to know how much of a concern we should have.

ES:

TC: Yeah, that’s what’s causing a lot of people to get concerned. A lot of the NGOs, a lot of the government scientists, a lot of the university scientists are getting pretty concerned at the trends they see in PBDEs in the environment. Some estimates coming out of work done in California, where they’re pulling a lot of this together, and they’re one of the more progressive states in taking the lead in trying to reduce the inputs of some of these compounds. Their synthesis documents basically are showing that basically these are doubling in the ecosystem every five to seven years, the levels going up that quickly in humans as well. The good news is I suppose is that in Sweden, where they have banned the production and use of most PBDEs – they did that several years ago – the levels in humans are now starting to come down. So, banning the use and distribution of some of these compounds will reduce their inputs, and that should result in reduced levels in the environment.

ES:

TC: They were believed to be inert, but biologically they are active. People have not done – that I’m aware of – definitive studies in humans – because that’s so hard to do. So those types of studies, obviously the human exposure studies, haven’t been done. And then when you try and look at humans, and tie in body burdens of PBDEs to functions in people, you don’t have that single variable. You have everything else that they’ve been exposed to as well. So it gets really hard to tease out. What we’re doing here at the Center is, we’ve just recently been designated as one of three NOAA Centers of Excellence in Ocean and Human Health. And this program is just getting started, but one of the tacks we’re going to take is that because we can’t study humans directly, and because so many of these contaminants end up in our oceans and in our surface waters, we can actually use the animals there to understand a little more about the implications for human health. We’ll use animals, marine mammals and fish as what we call sentinel species, to look for things like immune dysfunction, growth reduction, potential cognitive dysfunction, in association with exposure to these contaminants.

ES:

TC: Our main program here – we do chemical analysis nationally as part of the National Marine Mammal Health and Stranding Response Program. So our laboratory does chemical analysis for PCBs, for a number of different persistent organic pollutants in marine mammals nationally, and internationally. We’re focusing right now – we have a marine mammal program in Seattle, and we’re focusing on trying to understand the fluxes, or the pathways by which these contaminants are getting into the Orca whales. Is there anything we can do about it? If we clean up contaminated sediments in Puget Sound, where the orcas live for a good part of the year, will that reduce contaminant loads into prey, and therefore reduce the loads into orca whales? Or, as I talked about before, if these things are cycling through the ecosystem, is there anything constructive that we can do at this point. I tend to think, my personal belief is cleaning it up and getting it out of there is always going to make a difference in the long run. It will always help. But we need to know the rate at which these things might help, so that we can better allow managers to know how to prioritize different types of management actions to conserve these species like the cetaceans. People get a little confused – and it is confusing. People tend to think of contaminants as one thing, but contaminants – there are literally hundreds and thousands of them in the environment. We, working in toxicology tend to break them into classes of different contaminants, with some properties. But even so, when I talk about PAHs, for instance, the aromatic hydrocarbons, those are not really of concern for human health and for orcas and higher trophic levels in food webs, because they don’t bioacculmulate. They’re very quickly metabolized and excreted from the body. But the animals that are exposed can show biological effects in the process of taking them up, metabolizing them, and excreting them. But they don’t biomagnify. so you have to focus on those contaminants if you’re concerned about things like cetaceans, the higher trophic levels, then you focus on those contaminants that we call persistent, that basically don’t metabolize well in the body, and therefore do bioacculmulate as they follow the lipid through the food chain.

ES:

TC: I think so; I know that Washington State has a task force on what they call PBT, persistent bioacculmulate toxicants. There are a lot of acronyms flying around those fields. Many states, and most developed countries have people that are very concerned about persistent contaminants and the non-point source nature of it. And they’re grappling with what to do, how do you regulate it in the industrial process, how do you regulate it in post release, what are allowable levels in sediments and waters. So people are definitely getting concerned, but it is very much tougher to work on than the point source contaminants and things like oil spills. But again, I think the take-home message is that once these things get out in the environment, then you’ve lost a good deal of the battle. Because just getting them back out of the environment is so tough to do. People are concerned, people are working on it pretty diligently, and it’s really the question of resources and competing priorities. The problem with a lot of the contaminants is that you can’t see them. You can’t see them, you can’t tell they’re there; you don’t taste them, except in the case of something like an oil spill. So therefore it’s hard to get people behind doing something about it, because they’re invisible to the public.

ES:

TC: Well, we focus on a range of different contaminants, but the ones that we focus on quite a bit, what we call the persistent ones, they tend to bioacculmulate. They bioacculmulate, but what they do in the environment if there’s not fat around is they’ll stick to organic carbon, which is basically in aquatic ecosystems that’s particulate material. So what happens is generally, as soon as these compounds enter the ecosystem, whether it’s through street runoff or rainfall, or airborne deposition, they find a particle with organic carbon, and they latch on to it. And then these particles tend to coalesce and aggregate, and then they precipitate out, they settle out to the bottom. And so most of the persistent contaminants that we’re most concerned about end up in bottom sediments.

ES:

TC: Generally near shore areas. Again, these things are found globally, but the areas of the greatest contamination tend to be the areas closest to the cities, etc.. So they stick to particles, the particles settle out, in what we call depositional zones, areas where settlement accumulates – that’s where you tend to find most of the persistent contaminants. So that’s where you focus on – can you cap it, can you dredge it up and dispose of it in a sanitary landfill so that it’s contained. Those are expensive, messy propositions, but that’s are what people are doing to clean up some of their coastal environments.

ES:

TC: We did a study here in Puget Sound where there was a site that was very seriously contaminated with aromatic hydrocarbons, in the bottom sediments. And the fish there had rates of cancer and pre-cancerous conditions approaching 90% of the fish at this site. And the site was cleaned up by the EPA and the Army Core of Engineers, working together, and we were monitoring fish health at the site. It takes a long time for the health effects to wind down, because these effects take years to build up and it takes them years to go away, but after about 6-7 years, the rate of the cancer and precancerous legions of these fish dropped to less than 10%, and it looked essentially like a clean site. So, cleaning up areas can have positive effects – but again, that can be an expensive proposition.

ES:

TC: Add to list of science advisors on the list of toxicology, environmental toxicology

November is a time of maximum non-point source pollution in the Puget Sound – lot of rain and a lot of runoff.