Integrated Environmental Assessment and Management

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1 Integrated Environmental Assessment and Management IEAM Podcast 8.4 Transcript* Title: California Sediment Quality Objectives, with Steve Bay JENNY SHAW: Hello, and welcome to the podcast for the journal, Integrated Environmental Assessment and Management, better known as IEAM. I'm Jenny Shaw. The October 2012 issue of IEAM features a special series entitled "California Sediment Quality Objectives." These seven articles focus on impacts of contaminated sediment to benthic communities and address one aspect of a multiphase project to define sediment quality objectives that will be used to protect fish, wildlife, benthic invertebrates, and even humans. Joining me today is the guest editor of the series, Steve Bay. Steve is a principal scientist with the Southern California Coastal Water Research Project, or SCCWRP as it's known, and his work broadly centers on investigating the responses of marine life to environmental contaminants. Welcome, Steve. Thanks for joining us today. STEVE BAY: Thank you, Jenny. I am happy to talk to you about our special series. JENNY SHAW: And we can't wait to hear about it. So to get us started, would you briefly describe the larger program for developing sediment quality objectives in California? STEVE BAY: Sure. Well, the history on this program starts in the late 1980s when California incorporated into its water code a requirement to develop sediment quality objectives for protecting bays and estuaries in the state. Now, what happened was actually very little on that particular requirement for several decades, mostly because of the complexities that many of us are aware of in relating chemistry to biological effects in the environment. Our activities really started in the early 2000s, when, through a lawsuit, California was required by a court order to actually finally develop these sediment quality objectives, and that's when SCCWRP and our partner scientists were involved in the program. What we've been working with the state to accomplish is to develop an assessment framework to implement three sediment quality objectives, and these sediment quality objectives have the same regulatory power as water quality objectives would have in terms of going into permits and regulations and so forth. And so, they really consist of just three narrative objectives. One, basically, says that sediment contamination should not adversely impact the health of the benthic communities, the sediment-dwelling invertebrates in bays and estuaries. The second states that sediment contamination should not result in harmful human health impacts from people consuming local seafood 1

2 from these bays and estuaries. And that's what we call the indirect effects of sediment contamination through the food chain; whereas, for the benthic community, it's the direct effects that we're trying to protect. And then the third sediment quality objective relates to protecting fish and wildlife such as waterbirds from the effects of sediment contamination, either through their direct exposure or through the food chain. And so, the program itself, there's really -- what's interesting is there's only these three narrative sediment quality objectives that the state has adopted into its water board. The task that we have at SCCWRP is to help the state develop all the details that it takes to implement those. In many programs, that often is thought of as chemical-specific criteria that are used to just evaluate the sediment chemistry. What's different here for the state is that we're taking a much broader approach and developing specific assessment frameworks and really all the methods that go behind it to help them implement each one of those sediment quality objectives. So it's a very large program, and so far we've really only made substantial progress leading to a final adoption for just one of those three sediment quality objectives. JENNY SHAW: And would this be the phase that's presented in the special series articles? STEVE BAY: Correct. It's the first one I mentioned, which we use as a shorthand, would be the direct effects sediment quality objective, which basically states that sediment contamination should not adversely impact the benthic community. So the special series focuses on the work that we did on the technical side to really develop all of the details that it takes to implement that. And this is really, I would say, a fairly unique program within the United States, and what's unique about it is at a couple levels. First off, it's one of the few statewide regulatory programs that fully incorporates what's known as a sediment quality triad, which is the integration of three, what we call, lines of evidence to make an assessment of sediment quality. Those lines of evidence are sediment chemistry, sediment toxicity, and benthic community condition. So these three lines of evidence and this conceptual approach had been used for a long time in various types of monitoring programs both in the United States and internationally, but it's pretty rare that they're fully incorporated into a regulatory program, because beyond the conceptual approach, there's a tremendous amount of detail that you need to know to be able to implement them in a robust and consistent manner for a regulatory program. So that's what we really focused on in this program was to take it to all those next steps, starting with that multiple line of evidence approach and developing the thresholds for interpreting the individual data, the framework for integrating all of those types of results together to make a combined assessment of the sediment quality, and then also developing a means to classify and communicate those results that would be useful for both environmental managers, such as the regulatory agencies and also the individual scientists that are responsible for figuring things out at the next levels. JENNY SHAW: And scientists on this project examined several approaches for assessing impairment to benthic communities. Would you tell us about these approaches and a bit about how they were evaluated? 2

3 STEVE BAY: Yeah. Sure. Let me backtrack a little bit. There's probably two most noteworthy aspects of this program. First was to formally incorporate these three lines of evidence, and then the second was the kind of equal and full emphasis that we gave to interpreting the benthic community condition. This has always been the most difficult line of evidence for scientists to interpret because there really aren't good consistent and validated methods for interpreting the benthic community that can be used in kind of a broad program such as the statewide program in California. So we put a lot of effort into evaluating and refining various sediment quality indices based on the benthic community for that. And what we did is worked on developing four types of benthic community indices, and we focused on benthic indices which integrate information on abundance and species composition into a type of score value as opposed to looking at just individual metrics, something like species diversity. And the reason for that is what we found in our previous research is that these benthic indices are much more robust and have less variability than do kind of individual counts of species or measurements of species diversity. So they're more robust, and they're a little bit less affected by the variations small scale variations in habitat. The second big advantage of them is that they incorporate an evaluation to what the reference condition would be or the expectation of the reference in the index scores and thresholds. And this is really important because what it means is that programs can evaluate a few sites within their area of interest, and by using these benthic indices with the thresholds that we've developed, they can make a determination on whether or not those conditions are similar or different from the expectation for reference without having to analyze and interpret and find some suitable reference sites, which is commonly what's done for other benthic programs, and so it really greatly facilitates the using of benthic community data kind of at a small scale. So I mentioned we put a lot of work into developing these indices and adapting them from other programs, and there's really four types of benthic indices that we worked on. Two of them have been used previously in California. One is called the benthic response index, and this one looks at the abundance of individual species, and what we've done is determined what we call a pollution tolerance score for each of those species. So the general mix of species and their abundance gives us an overall score that relates to the pollution tolerance of that whole community. The second one is called the relative benthic index, and this has been used previously in California in some of its hot spot investigations. And so, we adapted and refined that index to give us a connection with some of the previous work in California, and that also uses a mixture of indicator species and abundance information. Two of the other indices are adaptations of other indices that have been used throughout the nation. One is known as an IBI or Index of Benthic Biologic Integrity, and it combines various types of metrics together to also give us a score that relates to how different that site is from the reference. And the third one is called RIVPACS. It stands for River 3

4 Invertebrate Protection and Classification System, and as the title indicates, it's often used in fresh water systems, and so what we did is adapted this conceptual approach, and I think for one of the first times applied it to the marine environment. And this index is a little bit different from all the others because it predicts the number of reference-type species, the most sensitive species, that you would expect if your study site was just a reference area without any contamination. And then it compares that predicted number of species to what's actually present at the site. And so, it's all based on the expected number of reference organisms versus what was observed. So the reason why we developed these four indices and we use all four in the program is because we found that no single index really was accurate enough or robust enough to just use by itself. And that was really a significant finding was that, you know, we needed to use a combination for the best results. How we figured that out was really one of the other really novel parts of the program, which was there is no reference sample or gold standard that you can use to evaluate the benthic community to judge the accuracy of these indices, like we have for chemical analysis. Traditionally, what's done is you get a couple of experts together, and they use their expert opinion or best professional judgment to determine the condition of the benthos, which is a little bit subjective and it's hard to reproduce over time, but we use that approach to evaluate and really calibrate these indices. So what we did is we got a group of nine experts that were national and had high degrees of local expertise to classify a subset of stations, and that became our gold standard the conditions that they determined of the benthic community for those sites, and then we compared each of these indices to that. And so, we were able to take this quantitative approach of judging the accuracy for each one of these benthic indices. So what we found is that no single index was accurate enough to be acceptable for just use by itself, but when we used the combination of these four indices that I just described, we were able to achieve an accuracy of about 90 percent relative to the experts. Basically, this combination of indices was just as accurate as any one of these experts might be in combination with other experts, and so that was a major challenge and, really, a novel solution to this problem of figuring out how best to interpret the benthic community. JENNY SHAW: So in contrast to the benthic community indices, your introductory paper in this series mentions a new sediment quality guideline index, or SQG index. I think our listeners would be interested in hearing about how this index could be used for identifying toxic hot spots, cleanup, and other remediation activities. Could you tell us about the development of the index and some of the data that were used? STEVE BAY: Sure. As I mentioned previously, most sediment quality programs put a high emphasis on comparing the sediment chemistry of the site to what's known as sediment quality guideline values for assessing the chemistry. So our previous research had indicated that the existing sediment quality guidelines didn't do that good of a job of predicting the likelihood of toxicity in the California sediments that we work with, so we put a lot of effort into this program into evaluating various indices, refining and calibrating them, and also seeing if we could develop perhaps a better performing approach that 4

5 might relate more directly to this sediment quality objective, which remember is for the protection of benthic community condition. So what you're referring to is that we developed a completely new sediment quality guideline index approach that we called a Chemical Score Index, and what's new about this is that it relates directly to the relationship of sediment chemistry to the benthic community condition. Most other sediment quality guidelines are really based on the relationship between chemistry and toxicity as you measure in a laboratory test. So there's always that potential for a disconnect between the toxicity results and the actual thing that we're trying to protect, which is the benthic community. So we were fortunate in California because of all of our work on benthic community indices that we had a large data set of benthic community and chemistry data that were matched that we could use to look at these relationships. And so we developed our very statistically intensive approach that looked at the relationships of individual sediment contaminants and the benthic community responses using these indices that I've talked about before. And what we did is we developed effect levels or thresholds for a subset of about 12 different chemicals that are the common ones that are measured in monitoring programs and related those to changes in the benthic community condition, and then this index is essentially a weighted average of those values. So now what we have is another tool in our toolbox for assessing sediment quality that relates directly to the chemical association of contamination on benthic community. What was really interesting in this study that we found was that those relationships, those effect thresholds and the overall index value that we developed for the benthic community relationship to chemistry, was actually very similar to that which we have previously documented for toxicity, and so that was really a new finding that really helps us put into perspective the relationships between toxicity and benthic community responses. Now, related to the second part of your question, which was using them in various types of activities like identifying toxic hot spots, cleanup, and remediation, one of the things that s really important in this program is that we recognize the limitations of these types of chemical indices for some of those activities. They're great for identifying the relative magnitude of chemical exposure, and so they are really helpful for identifying toxic hot spots, but for determining specific chemical concentrations for cleanup or remediation, really, none of the sediment quality guideline approaches that we are using or even have developed can really do a very good job for that. And so, what the program also talks about and gives some guidance on is that you really need to use other methods such as toxicity identification evaluations to really determine what the cause of the impacts are and to develop your cleanup levels based on that information in addition to the sediment quality guideline values. JENNY SHAW: I would be remiss if I didn't actually bring up the calculations behind these SQGs. A fair amount of effort has been invested in developing SQGs from toxicity assays, which are mostly derived from lowest effect concentration and no effect concentration values or "LOECs" and "NOECs." Given the recent spate of editorials and IEAM addressing 5

6 the statistical inadequacies of "LOECs " and "NOECs," should SQGs be so prominent in the decision framework, or is there hope that these metrics can be improved? STEVE BAY: Yes. Well, we were certainly aware of the concern and controversy about the statistics that you mention for interpreting toxicity tests in our program. My opinion is that that's not a critical limitation. First off, in the work we did, we tried to minimize those types of concerns by utilizing a combination of both statistics, like you mentioned, and also the magnitude of effect, which helps minimize some of these concerns for interpreting our toxicity results. But really what I think is the most important thing is that we need to recognize it's not so much the limitations of the statistical methods in my opinion, but the limitations of our chemical methods. Really, we don't do a very good job in monitoring programs right now of measuring chemistry in a way that corresponds to the actual dose that the organisms are responding to in these toxicity tests. We measure total chemistry, for example, not the portion that's actually bioavailable. So because of that, I think the level of uncertainty that we see in the relationship between chemistry and toxicity is driven mostly by that type of situation, the inability to do a very good job of measuring chemical bioavailability. It's much more important than it is these differences in the statistical tests. Like we did in this program, there's -- there are ways that you can deal with that, and, you know, the best way for expressing these toxicity responses is not just purely toxic or not, but is to really utilize the magnitude of response in your interpretation, and that's what we've done in the California program for working with our toxicity data. The importance of this issue on the chemistry limitations is also the reason why, in the guidance that we developed for this program, you know, we very strongly advise and, essentially, prohibit the users from just using the chemistry data the chemistry sediment quality guideline data just by itself. This was a very strong recommendation that the program received from our independent peer reviewers that provided guidance along the program which was that, you know, there really was never a situation where you could come up with a reliable assessment of sediment quality just based purely on the chemistry data by itself. JENNY SHAW: You mentioned that this is a three-phase program, and that the first part is what is covered in the special series in October. Could you tell us about the remaining phases of the program and what the next steps are? STEVE BAY: Certainly. As you mentioned, we're certainly in the midst of a longer term effort. So we're currently working on what's known as Phase 2 of the program. And Phase 2 focuses on that second sediment quality objective that I mentioned which was for looking at the impacts of sediment contamination on human health through consuming seafood, the indirect effects one. So we've developed an assessment framework that's, in some cases, conceptually similar but, obviously, different in the details to what we've developed for the direct effects. It uses a combination of fish tissue chemistry evaluation and also bioaccumulation modeling to provide the assessment relative to the objective. And we think that's a pretty robust framework that will work well for California. What we're currently focused on is developing the details and the guidance for implementing that so that it will work appropriately, and people will know how to interpret the results 6

7 for just the tremendous variety of applications that we have in California, everything from small lagoons or basins to very large estuarine systems such as San Francisco Bay. So we're hoping to finish that effort within the next couple years, and then it will come up for consideration by both the State of California and the EPA regional office. JENNY SHAW: Okay. Well, we'll look forward to hearing more about that then. So I understand there's also a short course related to this work that's being offered at the upcoming SETAC North America annual meeting, which is happening this November 2012 in Long Beach, California. STEVE BAY: Yes. Definitely. On the Sunday, you know, the official opening day of the meeting, we'll be conducting a full-day short course. Both myself and one of the key staff members at the California water board will be the instructors, and this will be a great opportunity for folks to learn in greater detail about the components and some of the critical methods and relationships that underlie this sediment quality objectives framework for the benthic community protection. And we'll include both a lot of descriptions of it, and also some hands-on experience in working with the data and the various data analysis routines which are really very specific to the program, and I hope will provide a good model for folks in other parts of the nation to consider as they move forward on this very important area of research. JENNY SHAW: Sounds great. Steve, thank you so much for taking the time to speak with us today. STEVE BAY: Well, I'm happy to, Jenny. I always enjoy talking about this program. It's been a big part of my life for almost the last decade here. JENNY SHAW: Well, and it sounds like we'll be hearing a lot more about this work as the next phases start coming into completion. STEVE BAY: Yes, I hope so. JENNY SHAW: For our listeners, you've been listening to Steve Bay discuss the special series, California Sediment Quality Objectives. Access the full set of papers in the October 2012 issue of IEAM. Just go to setacjournals.org. I'm Jenny Shaw, and thank you for listening to the IEAM podcast. (end of recording) * Transcription was generated from audio files and may contain minor errors due to sound quality. 7