QA/QC Program 



limit that can be achieved with current technologies corresponds to a 

 plausible-upper-limit risk that is substantially above risk levels of 

 potential concern (e.g., greater than 10'^ to lO"*). Tetra Tech (1985c) 

 provides further guidance on detection limits for bioaccumulation 

 surveys. 



Approved routine EPA methods for sampling and full-scjm analysis of 

 chemical contaminants in tissues are not available. U.S. EPA (1981) 

 published interim methods for sampling and analysis of priority pol- 

 lutants in tissues. EPA-approved protocols for chemical analysis of 

 water samples were adapted for application to tissue samples as part 

 of the Section 301(h) (Clean Water Act) marine discharge waiver 

 program of the Office of Marine and Estuarine Protection [see Tetra 

 Tech 1986e for 301(h) sampling and analysis protocols]. Specifically, 

 301(h) analytical methods for extractable organic compounds were 

 adapted from Method 1625 Revision B (U.S. EPA 1984a) and addi- 

 tional guidance from the EPA Contract Laboratory Program for Or- 

 ganic Analysis (U.S. EPA 1984c). When applicable, the 301(h) 

 protocols incorporate established EPA advisory limits for precision, 

 accuracy, and method performance (U.S. EPA 1984c). The EPA 

 Office of Acid Deposition, Environmental Monitoring, and Quality 

 Assurance is developing further guidance on sampling and analysis 

 methods to support exposure assessments. 



Other available methods for analysis of chemical contaminants in tissue 

 samples include those used by U.S. FDA (1978), NOAA (MacLeod et 

 al. 1984), and Ozretich and Schroeder (1985). These analytical 

 protocols are designed to apply to specific subsets of the EPA priority 

 pollutants. U.S. FDA (1978) methods, as described in the Pesticide 

 Analysis Manual, include variations in procedures for tissues differing 

 in lipid content. 



The choice of an analytical protocol may be influenced by available 

 financial resources. Chemical analysis of samples is often the most 

 costly portion of a sampling and analysis program. Higher analytical 

 costs may be required to achieve greater sensitivity (i.e., lower detec- 

 tion limits). Examples of analytical costs are shown in Table 5. At a 

 given level of sensitivity, a wide range of precision is encountered 

 among diverse organic compounds. For example, the low end of the 

 range of variation shown for extractable compounds in Table 5 can 

 usually be achieved for hydrocarbon analyses, whereas substantially 

 more variability is common for analyses of phthalates and some organic 

 acid compounds. A wide range of analytical costs is also encountered 

 at a given level of sensitivity (Table 5). Differences in analytical tech- 

 niques, laboratory experience with these techniques, and pricing 

 policies of laboratories account largely for the wide variation in cost. 



An adequate QA/QC program is essential for any sampling and 

 analysis effort to support exposure assessment. U.S. EPA (1984c, 

 1985c) provides guidance on QA/QC for chemical analysis. Tetra Tech 

 (19860 describes QA/QC procedures for field and laboratory methods 

 used by the EPA Section 301(h) (Clean Water Act) program. Horwitz 

 et al. (1980) provide guidance on QA/QC in the analysis of foods for 

 trace contaminants. Brown et al. (1985a) describe QA guidelines 



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