Development of a Systematic Approach to Accurately Measure
Trace Levels of VOCs arid SVOCs in Soil and Sediment

with High Moisture Content

John H. Zimmerman and Brian A. Schumacher
U.S. EPA/ORD/NERL/ESD-LV/CMB

Why?

IHtow?

The development of a single EPA method capable of accurately measuring trace volatile organic compounds (VOCs), water-soluble
VOCs, and semi-volatile organic compounds (SVOCs) is important for accurate and rapid risk assessment at Superfund, Resource
Conservation and Recovery Act (RCRA), and Brownfields site redevelopment programs as well as ongoing state site remediation
projects.

Thermal extraction was selected for examination because the technique is simpler and more efficient than the present EPA purge-
and-trap methods, and all water-soluble compounds are amenable to the procedure. Efforts were made to modify commonly used
instrumentation (e.g., Archon™ autosampler) and incorporate the compounds used for quality control in the present EPA methods
(e.g., internal standards, surrogates) so the proposed method can be easily adopted by routine analytical laboratories.

Currently, the use of thermal extraction for VOCs with the Archon™ autosampler has been evaluated with three soils: a soil with
high clay and negligible organic content from Georgia; a soil with low clay and medium organic content from Oregon; and a soil
with low clay and high organic content from Nevada. The influence of moisture on recovery of VOCs showed a decrease in
recovery with increased moisture (left graph below). To improve the recovery of analytes in moist soils, the use of a drying
agent was evaluated. In the Nevada soil with a 50% moisture content, a significant increase in recovery for a majority of ana-
lytes did not result with the use of either drying agent (CaCI2 or I^CO,,; right graph below). Future research will evaluate addi-
tional drying agents and other means of increasing the analyte recovery in high moisture soils and sediments.

160-
140-
120-

100-

02 80-

a?

& 60-
40-
20-
O

Nevada Soil - Influence of Moisture
on Analyte Recovery

o

—!—
5

80-
60-
40
20
0

Nevada Soil - 50% Moisture - Influence of
Drying Agent on Analyte Recovery

— No Drying Agent
CaCI

10

15

20

25

30

35

40

45

-|—

5

10

15

20

25

30

35

40

45

Analytes

Analytes

A modified Archon™ autosampler with a 200°C upper temperature
limit for sample thermal desorption is currently undergoing evalua-
tions for recovery of SVOCs. Once this SVOC system has been
optimized, the research will continue with the connection of the
VOC and SVOC gas chromatography/mass spectrometry (GC/MS)
systems to a single autosampler. When this connectivity is
achieved, the evaluation of the dual GC/MS thermal desorption
analytical system will begin. This research should be completed by
the end of 2005.

Collaborators

U.S. EPA/NERL-LV/ESD/CMB
U.S. EPA, Region 1
EST Analytical Inc.

126cm b05 .SF-Zim m erm an

Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use.

F

r ^ t

<

^eDSrX

*%\ epascienceforum



V

L\p«o/V

Collaborative Science
for Environmental Solutions

-------