DOE/ORO/2327 Oak Ridge Reservation Annual Site Environmental ...

Annual Site Environmental Report
Fig. 4.22. Temporal trends in mercury vapor concentration for the boundary monitoring
stations at the Y-12 National Security Complex, July 1986 to January 2010 (plots 1 and 2) and
January 1993 to January 2010 for AAS8 (plot 3).
A minimum of 5% of the samples in each batch submitted to the analytical laboratory are blank
samples. The blank sample traps are submitted “blind” to verify trap blank values and to serve as a field
blank for diffusion of mercury vapor into used sample traps during storage prior to analysis.
In order to verify the absence of mercury breakthrough, 5 to 10% of the field samples have the front
(upstream) and back segments of the charcoal sample trap analyzed separately. The absence of mercury
above blank values on the back segment confirms the absence of breakthrough.
Chain-of-custody forms track the transfer of sample traps from the field techs all the way to the
analytical lab.
A field performance evaluation is conducted annually by the project manager to ensure that proper
procedures are followed by the sampling technicians. No issues were identified in the last evaluation
conducted March 25, 2009.
Analytical QA/QC requirements include
• use of prescreened and/or laboratory purified reagents,
• analysis of at least two method blanks per batch,
• analysis of standard reference materials,
The Y-12 National Security Complex 4-43