IMW Initial Phase Report 



The QA/QC samples were as follows: 



A) Deer Island. A freeze dried (lyophilized) sample of Mytilus edulis tissue from a 

 large batch of samples collected several years ago from a coastal site near the Deer Island sewage 

 treatment plant, Boston, Massachusetts USA, homogenized, frozen and subsamples used in a 

 previous IOC/ICES QA/QC exercise for petroleum hydrocarbons. (Farrington et al, 1983). Each 

 laboratory received three sub-samples chosen by random. 



B) Staten Island. A batch of mussels collected from Staten Island in the harbor of 

 New York City, New York ,USA, was shucked to obtain tissues, blended, stored frozen (wet), 

 and distributed to the Analytical Centers. Each laboratory received one sub-sample for triplicate 

 analysis. These samples were prepared by Dr. Rodger Dawson and colleagues of the Center of 

 Estuarine and Environmental Studies, University of Maryland, USA for the GESRM Program of 

 IOC. 



C) NOAA-NIST. Samples prepared for the U.S. National Oceanic and 

 Atmospheric Administrations Status and Trends Program by the U.S. National Institute of 

 Standards and Technology as a working reference sample of a mussel tissue homogenate (soon to 

 be a Standard Reference Material) were distributed to the IMW Analytical Centers by U.S. NOAA 

 at the request of the Project Secretariat. Each laboratory participated in the NOAA-NIST 

 comparison exercise along with other NOAA-funded labs. 



D) IMW Field Samples. At nearly all collection sites, seperate "replicate" field 

 samples were taken. In several cases, seperate analyses of these field replicates were conducted by 

 each Analytical Center, splits of samples from 1 1 field stations were analyzed by both laboratories. 



All data resulting from the analyses of these QA/QC samples were reported directly to the 

 Project Secretariat and were not available to the other Analytical Center until a preliminary report 

 was distributed for the Sao Paulo data review meeting in April of 1993. A review of the available 

 data prior to the Sao Paulo meeting led to the discovery that the Analytical Centers had 

 inadvertently reported results from a different working reference material of the NOAA-NIST 

 sample set. This error was subsequently rectified with one laboratory reporting additional data for 

 the correct sample. 



In addition to the Analytical Center QA/QC program, participating Host-Country 

 laboratories received splits of field samples, Standard Reference Materials and a working reference 

 freeze-dried tissue sample for analysis. A summary of the results of that exercise is reported in 

 Appendix C. 



Detection limits reported by the two Analytical Centers are listed in Table 2. The two 

 laboratories routinely use different philosophies and methodologies in arriving at what they each 

 term "detection" limits. GERG follows U.S. Federal agency requirements and MEL, as a U.N. 

 laboratory, has adopted a UNEP reference method. (See footnotes in Table 2.) 



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