Appendix C: QA Comparison Exercise 



analyses of bivalve tissue and QA sample) to the Project Secretariat. Participation in this exercise 

 was voluntary, but we emphasized that in order to create a future regional database from the results 

 of combined analytical efforts, intercomparison exercises were essential. 



We requested that each analyst use the analytical method currently in use in his/her lab and 

 report the analytes normally reported. In addition, we asked that complete analytical results 

 including QA information listed below, be included in addition to analyte concentrations. Such 

 information, is essential for one laboratory's data to be compared with that from other laboratories. 

 QA Information requested: 



• sample weight (report dry weight and how derived) 



• extract weight (total lipid) 



• SRM recovery spikes used and amount spiked per sample 



• % recovery (include how calculated) 



Note: recovery data from other (i.e., non-EMW) tissue analyses run in each lab was requested as 

 well, if available. We anticipated the analysis of one internal recovery spike in the triplicate 

 analysis of freeze-dried tissue homogenate. 



• lab blank results (and lab limit of detection) 



• sample injection volume, total sample volume (gc) 



• quantification calculations, including total amount of analyte concentration relative 

 to extracted tissue 



• a copy of the analytical method used 



A total of 12 Host-Country laboratories retained EMW-collected tissue samples for analysis 

 at the time of the visit of the IMW Field Scientist. All of these laboratories received a collection of 

 Standard Reference Materials (SRM's) and a freeze-dried tissue from the Project Secretariat along 

 with instructions for reporting results. Six labs have reported analyte concentration data in the 

 freeze-dried sample supplied to the Project Secretariat. The total number of reported analytes and 

 the specific analytes reported by any single lab varied greatly, as did the level of detail of 

 methodology and quality assurance data. For these reasons, a complete discussion of this data, as 

 is presented in the body of this report is not possible. A summary of the data is presented in Table 

 C2. 



Given that the IMW Host Country interlaboratory comparison exercise began at the final 

 step of the ideal iterative exercise described above, the results are encouraging and should cause the 

 participating analysts to look forward to future exercises. Variations in the reported results cannot 

 be explained here because insufficient analytical detail was available to make valid comparisons. 



Some data on organic contaminant concentrations in environmental samples from the IMW 

 Initial Phase Region has been published and selected reports are cited in the reference section of 



C3 



