&ER&
United States
Environmental Protection
Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
*
Research and Development
EPA-600/S2-81 -165 Mar. 1982
Project Summary
Portable Miniature
Sampler for Potential
Airborne Carcinogens in
Microenvironments:
Phase 2. Evaluation
J'JN -S1S82
UBRARY, REGION M
D. S. West, F. N. Hodgson. J. J. Brooks, C. L. Heflin, T. W. Hughes, and C. R.
The collection, concentration and
analysis of a broad range of organic
compounds from ambient air has been
a challenging problem for environmen-
tal researchers for a long time. Prob-
lems with measuring organic pollu-
tants in ambient air include specificity
to individual compounds, detection
limits for ambient co-concentrations.
cumbersome size of sampling equip-
ment, complexity of analysis, artifact
formation in the sampling and analysis
protocols, and costs associated with
data generation. A portable sampling
system has been developed for ambient
air levels of organic contaminants. The
system utilizes a combination of solid
sorbents for sample collection and
GC/MS analysis to solve the prob-
lems associated with ambient air meas-
urements for organics.
This Project Summary was develop-
ed by EPA's Environmental Science*
Research Laboratory. Research Trian-
gle Park. NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Overview
A portable sampling system was
developed for the collection and concen-
tration of a broad range of organic
compounds from ambient air. the system
is based on the use of three solid sorbent
materials, Tenax-GC, Porapak R, and
Ambersorb XE-340 arranged in series,
through which air is drawn by a portable
battery-powered pump. Two different
portable pumps. DuPont P4000 and
Spectrex PAS 3000, were used to power
the portable sampling device in field
evaluations of the system.
The system was evaluated in field
studies conducted in Dayton, Ohio; Los
Angeles, California; Houston, Texas;
Niagara Falls, New York; Research
Triangle Park, North Carolina; and Cin-
cinnati, Ohio. Both indoor and outdoor
environments were included among
those sampled. Analyses were conduc-
ted for selected target compounds as
well as additional broad-scan qualitative
analyses of collected organic compounds.
Analyses of the samples were accomp-
lished using thermal desorption of the
sorbent materials followed by capillary
column gas chromatography/mass spec-
-------
trometry (GO/MS). Partial pre-analysis
fractionation (based primarily on vola-
tility) was obtained in some of the
sampling applications, demonstrating
that in certain environments additional
capacity beyond that of Tenax-GC may
be required to sample low level organic
atmospheric pollutants.
System Description
The general population, particularly
in urban areas, is exposed to a wide
variety of atmospheric pollutants. Cur-
rently, the health hazard posed by this
situation cannot be adequately defined
because of the complexity of the prob-
lem and the lack of sufficient, reliable
data. One of the needs in assessing this
exposure problem is a reliable screen-
ing technique for determining what
substances at what concentrations are
present in our ambient atmosphere.
The ability to assess the extent of a
health hazard in ambient air requires at
least three things:
1. knowledge of the materials that
pose the hazard,
2. a reliable sampling technique for
collecting these materials, and
3. adequate technology for accurate
analyses of these materials.
The objective of this research program
was to develop a portable miniature col-
lection system that could be used to
assess the exposure of an individual to
atmospheric pollutants, especially those
pollutants that potentially threaten the
health of the individual. Since a wide
variety of gases, vapors, and particu-
lates of organic compounds, ranging
from volatile hydrocarbons (e.g., meth-
ane) to high molecular weight phthalates
(plasticizers), polych formated biphenyl
pesticides, and polynuclear aromatics,
are present as pollutants within the
atmosphere, the collection system was
to be capable of concentrating a wide
variety of organic compound vapors from
ambient air. A number of organic com-
pounds suspected of being carcinogens,
mutagens, cofactors, or precursors, and
therefore of environmental and health
concern, was to be selected for specific
evaluation.
Procedure
Athree-sorbent, portable sample col-
lection system was designed, evaluated,
and field tested in Dayton. The sorbents
were operated in series, drawing air in
turn through Tenax-GC, Porapak R, and
Ambersorb XE-340 using a small per-
sonal pump. This selection of sorbent
materials was judged the best combina-
tion of commercially-available sorbents
for broad-range organics sampling. Two
types of small personal pumps, DuPont
Model P-4000 and Spectrex Model
PAS-3000, were used to collect samples
during these field evaluations.
The result of this research is a samp-
ling system and associated analytical
methodology that is capable of screen-
ing for a broad range of organic compo-
nents in ambient air and, in particular,
for assessing the presence or absence
of the selected potential carcinogenic com-
pounds. This study represents a step
toward a reliable approach for assessing
the health hazard to an individual posed
by potentially carcinogenic materials in
ambient air.
Results
In terms of concentrating organic
compounds on the sorbent materials,
the portable sampling system operated
as anticipated in field sampling applica-
tions. The need for additional, comple-
mentary sorbent capabilities besides
those of Tenax was demonstrated in the
Los Angeles and Houston samples
where significant amounts of organics
were observed on the subsequent (Pora-
pak and Ambersorb) tubes. A partial
fractionation was also observed on the
various sorbent materials where differ-
ent ranges of compounds (based primar-
ily on volatility) were found. Some influ-
ence appears to be exerted by matrix
and humidity effects on the amount of
breakthrough observed on the latter
sorbents. The Niagara Falls and Research
Triangle Park samples were collected in
an interior environment and exhibited
little if any compound breakthrough
compared to the Porapak and Ambersorb
materials. Figures 1, 2 and 3 represent
the portable sampling system.
The analytical methodology is based
primarily on capillary column GC/MS
using thermal desorption for recovering
the sample from the sorbents for anal-
ysis. Samples collected in high humidity
environments (e.g., Houston) caused
particular problems in the analysis
phase due to high concentrations of
water collected on the Porapak and
Ambersorb sorbents. However, research-
ers found that by changing certain
analytical parameters (e.g., initial GC
temperature), a satisfactory analysis
could be performed in these instances.
-------
Sampling Ports
(Hoses Opt.)
Sampling Tube,
(3) Holder
Flow Meters
"71
/•
"71
/•
-71
*- Pump. Battery.
& Charger
Weight
Cost
Operational time
Method of setting flow
Durability problems
Needle Valves
2.3 kg « Sib)
$635 for DuPont P4OOO-A (pump, battery
and charger only)
>8h
Needle valves and small flow meters
Needle valves fragile and pump near
maximum for long periods
Figure 2. The "tube tray"portion of
the Ambient Air Collection
System.
Figure 1. Sketch and description of a small personal sampler.
-------
D. S. West, f. N. Hodgson, J. J. Brooks, C. L Heflin, T. W. Hughes, and C. R.
McMillin are with Monsanto Research Corporation, Dayton, OH 45407.
James Mulik is the EPA Project Officer (see below).
The complete report, entitled "Portable Miniature Sampler for Potential Airborne
Carcinogens in Microenvironments: Phase 2. Evaluation," (Order No. PB 82-
129 461; Cost: $18.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, MA 22161
Telephone: 702-487-4650
The EPA Project Officer can be contacted at:
Environmental Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
•fa U S GOVERNMENT PRINTING OFFICE, 1982 — 559-017/0736
Figure 3. Portable Miniature Collec-
tion System.
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
PS 0000329
U S ENVIR PROTECTION AGENCY
REGION 5 LIBRARY
230 S DEARBORN STREET
CHICAGO IL 60604
------- |