K ra One { i PUTT oR 3 BACKGROUND ACTIVITY I rrr 104 0 LLptti ye 2 4 6 8 tt sept pe et 10 12 14-16 18 20 22 24 26 28 30 32 34 36 38 40 SAMPLE NUMBER ' Fige C.17 Example of Relative Background Activity, Station 251.09 (sampler exposed but did nut operate) 132 ae a ;.