Quality control , SPMDs

In subsequent chapters, we provide an overview of SPMD fundamentals and applications (Chapter 2) the theory and modeling which includes the extrapolation of SPMD concentrations to ambient environmental concentrations (Chapter 3) study considerations such as the necessary precautions and procedures during SPMD transport, deployment, and retrieval (Chapter 4) the analytical chemistry and associated quality control for the analysis of SPMD dialysates or extracts (Chapter 5) a survey and brief description of bioassays-biomarkers used to screen the toxicity of SPMD environmental extracts (Chapter 6) discussions on how HOC concentrations in SPMDs may or may not relate to similarly exposed biomonitoring organisms (Chapter 7) and selected examples of environmental studies using SPMDs (Chapter 8). In addition, two appendices are included which provide... 

The application of appropriate Quality Control (QC) procedures or criteria is a mandatory consideration in the deployment and analysis of SPMDs (e.g.. Petty et al., 2000a). Similar to any performance-based methodology or approach. 

DeVita and Crunkilton (1998) have examined QC associated with the use of SPMDs. The results of their study demonstrated that quality control measures applied to SPMD analysis met or surpassed conventional guidelines (EPA Method 610 for PAHs in water was used for this comparison) for precision and accuracy. This elevated level of data quality was achieved even though measurements of both overall precision and accuracy of SPMD data encompassed more steps (each with the potential for variability) than the conventional method. In summary, DeVita and Crunkilton (1998) found that QC measures could be used to validate data from the analysis of SPMDs used in the field. In view of the state of SPMD QC, it appears that the SPMD approach for monitoring hydrophobic organic contaminants is equivalent to some EPA-approved methods. 

SPMD dialysates (extracts), rinses of the exterior membrane surface (only SPMDs exposed to air), and aliquots thereof often contain a number of classes of chemicals. Figure 6.1 shows various levels of processing and enrichment used for SPMD derived bioassay samples. We strongly recommend the use of SPMDs with triolein purified by the method of Lebo et al. (2004) for bioassays to reduce the probability of false-positive results or for controls that fail to meet quality control... 

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