Common use of Laboratory Analyses Clause in Contracts

Laboratory Analyses. The soil vapor samples were submitted to Sequoia Analytical Laboratory on the day of sample collection. Soil vapor samples were analyzed within 24 hours of receipt. Laboratory reporting sheets of the analytic results are contained in Appendix C. Soil vapor analytic results are summarized in Table 4. It should be noted that all trip blanks contained detectable levels of contaminants. Methylene chloride was detected in trip blanks for sampling performed on April 27, 28, and July 6, 1989. Methylene chloride is a chemical that is widely used in a number of products and applications, is found in ambient air in the Bay Area, and is typically used in analytical laboratories. The trip blanks suggest that methylene chloride concentrations detected in the samples below approximately 50 ppb may be the result of sample or laboratory contamination. The presence of chloroform in one of the trip blanks (April 28, 1989) and of benzene in another trip blank (July 6, 1989) suggested that both chloroform and benzene detected in the samples below approximately 10 ppb may also be the result of contamination. 112 TABLE 4 COMPOUNDS DETECTED IN VAPOR WELL▇ Well Number Compound Detected Concentration (ppb) ----------- ----------------- ------------------- Samples taken on April 27, 1989