Re-evaluation of the Applicability of Agency Sample Holding Times

Re-evaluation of the Applicabil ty
of Agency Sample Holding Times

Brian A. Schumacher, ORD/NERL/ESD-LV/CMB
Calvin C. Ainsworth, Battelle-Pacific Northwest Laboratory
Eric A. Creceiius and Valerie I. Cuilinan, Battelle-Marine Sciences Laboratory

Background:

How We
Did It:

Holding times are the length of time a sample can be stored after collection and prior to analysis without significantly affecting the
analytical results. Maximum holding times (MHTs) have been established by the U.S. Environmental Protection Agency (U.S. EPA)
and have been presented in the Code of Federal Regulations and SW-846 methods manual.

Contaminated soils and sediment samples were collected from across the U.S. via our Regional partners and other supporting
Regional personnel. Samples were homogenized and preserved at either 4° or -20° C. Analyses were performed following
standard SW-846 methods. Samples were analyzed at times 0, 0.5 MHT, 1 MHT, 2 MHT, and up to 12 MHT depending upon
the contaminant being investigated.

What We
Found:

PAHs - 3 ring

~ Fluorene 4 °C A Fluorene -20 °C

Chromium(VI)

PAHs - 4 ring

Pyrene 4 "C ~ Pyrene -20 »C

7000
6000
5000
4000
3000
2000

;§IbA» »-

:i *! I

q 20 40 60 80 100 120 140 160
time (days)

Pesticides

PCBs

2,2',3, 4,4', 5,5" - Heptachlorobipheny» -20 °C A 4 °C

1200
1000

~» A

Summary:

Heavy metal concentrations (MHT=6 months) were not significantly affected by a holding time of 364 days.

Chromium(VI) concentrations for soil/sediments stored at either 4° C or -20 C are stable far beyond the required 30-day MHT.

Pesticide concentrations remained steady through 4 MHTs (MHT=14 days to extraction and 40 days after extraction),
regardless of storage temperature.

PAH concentrations remained steady through 4 MHTs (MHT=14 days to extraction and 40 days after extraction), except in one
sediment where the concentrations of the lighter (3-ring) PAHs decreased significantly after 2 MHTs when stored at 4° C.

PCB (aroclors and congeners) concentrations remained steady through 4 MHTs (MHT=14 days to extraction and 40 days after
extraction), regardless of storage temperature.

Our

Our partners included - U.S. EPA Regions 1 and 10, U.S. EPA ORD, and many Superfund Remedial Project Managers.

Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

f' a \ epascienceforum J

1 ^^7 | Collaborative Science

for PnuirnnmAntal £nlntinnc

X M

Collaborative Science
for Environmental Solutions

-------