Gulf of Maine Projects

Final Report: Evaluation of the Gulfwatch Monitoring Program

Gulfwatch Review (cont.)

Future Program Design Modifications

Hypothesis Testing

Now that direct field experience has been acquired and the strengths and limitations of this approach are specifically known, it is appropriate to return to ask a specific testable question. This is a critical step, from which the entire program should develop. There are differences between monitoring to measure compliance with existing requirements (e.g., to meet outfall permit requirements) and monitoring to determine spatial and temporal trends in contaminant distributions. Both are important activities but data collected for one purpose are usually not applicable for another and the goals for data collection must be clearly stated at the outset. The incentive to overuse monitoring data will be reduced if both data collectors and resource managers clearly understand the inherent limits on any data set. These limits become apparent if clear statements of purpose are included with the data.

During this just-completed initial implementation phase of Gulfwatch, a necessary focus on the mechanics of starting a new program has somewhat obscured this very basic issue. The Gulfwatch program has responsibly evolved in response to realities of the field sampling but this response has focused on the logistical and programmatic details while losing sight of the higher level mission questions. The program has reacted to logistical issues and made methodological adjustments well. It is now an appropriate point in time to use the 5-year experience base to reassess program mission and as well as methods.

Sampling in Environmentally Relevant Scales

As Gulfwatch evolves, and if it expands in scope beyond tissue sampling, samples need to be taken with an understanding of ecosystem complexities and the processes governing variability in each compartment of the ecosystem if meaningful data are to be generated. For example:

Water : The coastal water mass, driven by stormand tidal energy, is changing vertically and horizontally on the time scales of minutes-to-hours; extremely low concentrations of toxic organics in sea water cannot be detected easily by standard analytical methods.

Biota: Tissue concentrations can vary with physiological state, age and health of the organism and season. The organism's location in the food web and habitat characteristics can have an effect on contaminant distribution and concentration.

Sediment : Concentrations of organic contaminants in sediments are usually correlated with the organic carbon content and grain size distribution; therefore a sampling strategy for organics should first assess such bulk parameter distribution. Muddy, high carbon sediments are usually a long-term reservoir of toxic contaminants and should be the primary sampling focus. For nutrient-related issues, sediments are the site of major nutrient transformation within the system and more frequent sampling may be required to resolve the rates and extent of nutrient biogeochemistry. A sampling strategy involving sediments and may require sampling in different spatial and temporal scales to resolve issues of toxics, nutrients and pathogens.

One specific Gulfwatch issue related to sampling with respect to environmental complexities relates to clearing of the gut prior to analysis. Evidently, the program decision not to allow the guts to clear was to provide parity with NS&T as well as to simplify the procedure. This decision presents a problem in areas with high suspended sediment loads. The observed order of magnitude difference in aluminum (Al) concentrations clearly represents something other than body burden but this question cannot be resolved with existing data. Perhaps this is an area where further testing could be done; one possibility is to routinely allow the caged mussels to clear their guts before analysis (if this aspect of Gulfwatch continues; see discussion below) and then test deploy them in areas where high suspended loads are suspected to be causing a problem. If this alternative is attempted, possible loss of organics with gut clearing must be considered. As collected, the caged mussel data are not directly comparable to native mussels for some questions, in any case. This gut-clearing issue is also related to data that was omitted from analysis because the iron (Fe) and aluminum concentrations were unexpectedly high. The logical explanation offered was that gut contents of sediment were probably high. Perhaps the tissue data could be salvaged by analysis of the Metal/Al or Metal/Fe ratios? It would also help the interpretation of metal concentrations to know the concentrations in bottom and suspended sediments at the sampling site. A reassessment of the program should include reconsideration of sediment sampling in some cases.

Gulfwatch and NOAA

National Status and Trends (NS&T) sampling periods are offset by 6 months. Previously published studies have shown that seasonal patterns exist in mussel metal body burdens and concentrations (Phillips, 1976, 1980 ). Mucklow (1996) reports a similar result in the Gulf. For most metals, Gulf concentrations were higher in the spring than in fall. In addition, differences in the physiological state of the mussels in spring vs. fall may affect contaminant burden and there are also likely to be seasonal differences in inputs (although the NS site studied by Mucklow was located near a sewage outfall which may have been a relatively constant local source of metals). Mussels removed some distance from local sources of pollutant may reflect contaminants from distant sources in the spring when river discharges are at their highest and therefore show an even greater seasonal change in concentration. These environmental and physiological factors make the direct comparison of data between NS&T and Gulfwatch difficult. In addition, there appear to be some differences in the analytical methods which are discussed below. One suggestion might be for Gulfwatch to sample the NS&T sites more often in one year in order to provide information on seasonal variation at these sites and allow for a direct comparison of data with the labs running the NS&T samples. Gulfwatch certainly should regularly participate in the inter laboratory comparison exercises conducted by NOAA.

Benchmark stations were chosen in an effort to quantify interannual variability. It would seem best to choose these stations to represent fairly clean sites which respond to regional scale pollution inputs. There may also be strong reasons to choose benchmark stations in heavily contaminated areas to address specific management questions; for example, Deer Island would have value as a benchmark for many questions relevant to the Gulf. By monitoring these benchmark stations annually there should be a reasonable chance of picking up regional trends in 3-5 year time scales. However, as presently designed, the number of benchmark stations is fairly small and it's not obvious that they are sufficiently removed from local contamination sources that might skew their value as representative of the Gulf-region. It would be good to consider moving some of these stations and increasing the number if this variability detection objective is to be met.

Reviewers note that the reported limit of detection for most analytes is higher than that of NS&T. Trace concentrations in samples require more elaborate, often non-standard analytical methods that account for analytical artifacts and recovery levels (e.g., high resolution, low detection limit, negligible "blank" concentrations, etc.). This issue must be resolved by Gulfwatch through improved QA/QC practices and inter laboratory comparison before data can be produced in relatively clean areas to resolve the interannual question. A regional program such as Gulfwatch has an opportunity to focus on regional issues such as long-distance atmospheric transport that local programs, with their inherently narrower focus, normally cannot. Some contaminants have a distant source (Pb from gasoline, PCBs, etc.) as well as local sources and by selecting an adequate number of stations, these multiple sources might begin to be sorted out. Such questions are prime candidates for partnerships between a monitoring program and academic research efforts.

Overall, the issue of benchmark stations should be re-examined by Gulfwatch. By only monitoring the other sites every 3 years it will take a decade or more to determine if an individual site is getting cleaner or more polluted. This seems to be an acceptable time-frame, given the regional nature of the program and the current funding level, but it also implies a continued long-term source of program support.

Links to On-going Research

The bivalve monitoring concept has been successfully tested at local, regional, national and international scales for more than three decades. The best of these programs have allocated adequate resources for communication of results and for QA/QC activities. These successful programs have also kept up-to-date with these activities by maintaining close links with academic researchers who are also working in the area of coastal environmental quality. Successful monitoring programs are designed to make as simple a measurement as possible, but monitoring measurements must be interpreted in the context of ecosystem complexities. Data interpretation and the decision of when to move up to more expensive measurements would benefit close dialog with active research projects. The search for simple answers to complex questions is a recipe for failure. Newer methodologies and techniques may be necessary to address specific questions and monitoring program links to academic research is essential if the program is to make use of (or even be aware of) these new methods. Interesting peripheral questions and some of the "high-tech" analyses can be addressed through partnerships between the monitoring program and academia.

Gulfwatch is ideally situated to build these connections but does not seem to have done so to date because of the initial phase focus on start-up details. These links need to receive much higher priority as the program matures and will require program resources.

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