Laserfiche WebLink
ambient air sampler pumps and SS for the integrated surface walk <br />sampler pumps. <br />Field blanks were used to determine if samples were contaminated <br />through handling procedures other than sampling. Tedlar bags were <br />prepared by the procedure described under "Tedlar Bag Preparation" to <br />verify that the bags and the nitrogen used as the blank reagent were <br />free of contamination before they were shipped to the landfill. <br />The field blanks were transported to the landfill in light -sealed <br />boxes in the sampling van. The blanks remained in the field during <br />the test period and were shipped with the air samples to the laborato- <br />ry for analysis with other samples collected on that day. The blanks <br />were labeled to be indistinguishable from the other field samples. <br />The field blank designations for the Foothill Sanitary Landfill were <br />AA -5, AA -10, and AA -15. All three samples contained benzene (0.6 to <br />1.7 ppb). Sample AA -5 contained 1,1,1 -trichloroethane (0.4 ppb). The <br />concentrations of these compounds were all below their respective <br />regulatory detection limits. Table 7 summarizes the data for the <br />field blanks. The field information and analytical results are <br />included in Appendix H. <br />The presence of low concentrations (less than 2 ppb) of VOCs in the <br />field blanks may be a result of compounds bleeding from the Tedlar <br />bags or permeating from the laboratory atmosphere into the Tedlar <br />bags. <br />In discussions with the Bay Area Air Quality Management District <br />(BAAQMD) laboratory, EMCON learned that the BAAQMD has found that <br />Tedlar bags bleed some of the volatile compounds of interest --in <br />particular, benzene --at concentrations up to 3 ppb. The BAAQMD has <br />also stated that volatile compounds in the laboratory atmosphere may <br />PJ9 9390405.00D 5-3 Rev. 0 09/07/88 <br />Emcon Associates <br />