Gulf of Maine: Council on the Marine Environment

Gulf of Maine Projects

Final Report: Evaluation of the Gulfwatch Monitoring Program

Gulfwatch Review (cont.)

Sampling and Analysis

Appropriate Sample Collection and Sample Handling

The choice of methods for measuring nutrient or toxic contaminants and for enumerating pathogens will be dependent on the nature of the management question being addressed (e.g., regulatory requirements or a more detailed analysis of sources and fates). Monitoring staff should be prepared to choose appropriate methodologies and to conduct a quality control/quality assurance program for all measurements made. In many cases, a lower resolution "standard method" may be required by regulation. The high resolution method may be used to provide higher precision and accuracy in circumstances where that level of analysis is warranted to address a specific question. These analytical methods are always more expensive and often cannot be conducted using the same apparatus or even the same laboratory space. A less sensitive analytical method may be adequate for a baseline survey and screening techniques that measures some bulk parameter may be a sufficient analytical tool in many cases. The choice of appropriate analytical methodology should be made in reference to already-defined management needs and this step needs to be reevaluated by Gulfwatch.

Ancillary Measurements

The use of "transplanted" mussels in cages can be a powerful adjunct to sampling native populations to address some scientific or management questions. Caged mussels have been used by Gulfwatch to compare native tissue burdens to uptake by transplanted animals. Although the 5-year report discusses in great detail possible reasons why the transplanted mussels may have overshot the native mussel concentrations, the most likely conclusion that these results are due to an experimental artifact still needs to be ruled out. The caged mussel aspect of the program is time consuming and expensive. The data obtained from the transplant experiment does not seem to be based on any specific management question. The use of caged mussels by Gulfwatch should be reconsidered and incorporated into the program only when uptake data is required for a previously identified purpose.

It is appropriate that growth and Condition Index (CI) be monitored, but there is little hope that these measurements will ever be linked back to contaminate burdens except in grossly polluted sites. CI data reported by Gulfwatch is very variable and does not permit unequivocal conclusions. Growth is strongly affected by food availability and other factors that are beyond the scope of this monitoring program. The use of newer technologies (e.g., cellular or molecular indicator of exposure) seems to be a better approach, and the introduction of such new techniques to Gulfwatch will require strong collaborative links between the program and academic researchers. One specific question arises related to growth that should be resolved by Gulfwatch before drawing conclusions from the data: mussels of similar size are being collected but do we know they are also of similar age? This detail would be useful for interpreting the body burden data. Growth data has been produced but it is not discussed in the 5-year report; even if these results are confusing, the attempt deserves discussion (even if only as a reassessment of this parameter as an included component of the monitoring program).

Necessary and Sufficient QA/QC

QA/QC and inter laboratory comparison results are an essential component of monitoring reports and must be integral to the conclusions drawn. Quality control protocols are well-described in Gulfwatch reports for the metal and organic analyses but the information on standard reference materials, limits of detection, blank analyses and spike recoveries are missing. What is the comparison between the observed concentrations of metals or organics and published (accepted) concentrations on standard reference biological materials, for example? Apparently, Gulfwatch is generally following the analytical procedures of NOAA NS&T and has participated in some inter-laboratory comparison exercises. However, the results of this work are not reported in the Gulfwatch materials reviewed. The fact that appropriate QA/QC has apparently been carried out is to be applauded, but reporting these results is an essential and integral part of the tissue concentration interpretation. Gulfwatch data at this point are uninterpretable (and therefore unreviewable) because this essential information is missing. Articles by Taylor, (1985, 1985a) provide good overviews of this critical topic. Community standards exist for this presentation (NOAA, 1993; UNEP, 1990, Villeneuve and Mee, 1991 and 1992). In addition, NOAA and UNESCO have published manuals for the use of standards and reference materials (NOAA, 1994; UNESCO, 1990; UNEP, 1990; UNEP, 1991).

Reviewers identified a detection limit difference between NOAA and Gulfwatch above. Gulfwatch partially addresses this detection limit issue in a discussion the 5-year report. This summer, we supervised a student intern who attempted to use a combination of Gulfwatch and NOAA NS&T data to create a combined database in an effort to elucidate regional trends in space and (if possible) time. We found that the limits of detection in the Gulfwatch data are higher than those of NS&T, making it impossible to create a usable combined dataset except in highly contaminated areas such as Boston Harbor. The incomplete QA/QC discussion in Gulfwatch reports does not permit a user to identify the precision or accuracy of reported concentrations, rendering the dataset useless for many purposes. This important issue deserves vigorous attention by Gulfwatch and the application of a significant portion of Gulfwatch resources to an on-going QA/QC effort.