DOC
EPA
United Stales
Department of
Commerce
National Bureau of
Standards
Washington DC 20234
United States
Environmental Protection
Agency
Office of Monitoring and Technical
Support
Washington DC 20460
EPA 600 4 80-042
August 1980
Research and Development
Survey on Research
Needs on Personal
Samplers for Toxic
Organic Compounds
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2, Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
•9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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A SURVEY ON RESEARCH NEEDS ON PERSONAL SAMPLERS FOR
TOXIC ORGANIC COMPOUNDS
by
Jimmie A. Hodgeson and Alexander J. Fatiadi
Center for Analytical Chemistry
National Bureau of Standards
Washington, D.C. 20234
Interagency Agreement No. AD-13-F-0-034-0
EPA Project Officers
Lance Wallace
Office of Monitoring Systems and Quality Assurance
Environmental Protection Agency
Washington, D.C. 20460
and
Eugene P. Meier
Quality Assurance Division
Environmental Monitoring Systems Laboratory
Environmental Protection Agency
Las Vegas, Nevada 89114
Prepared For:
OFFICE OF MONITORING SYSTEMS AND QUALITY ASSURANCE
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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DISCLAIMER
This report has been reviewed by the Office of Monitoring and
Technical Support, U. S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U. S. Environmental Protection Agency, nor
does mention of trade names or commercial products constitute or recommenda-
tion for use.
ii
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FOREWORD
This report is one of a series of reports designed to provide
information on the development of Standard Reference Materials and
measurement methods in support of quality assurance for environmental
monitoring. The National Bureau of Standards and the Environmental
Protection Agency have entered into an interagency agreement to
coordinate the standards and measurement services activities of NBS
with the quality assurance programs of EPA. Reports of work carried
out under this agreement will appear in the EPA Environmental
Monitoring Research Report Series.
Under this agreement, NBS will develop and provide, as directed
by EPA,
Standard Reference Materials
Improved or new measurement methods
Standard measurement instruments
Calibration standards and protocols
as well as other services deemed necessary for assuring the accuracy
and reliability of environmental monitoring data. Standard Reference
Materials developed under this agreement will be available for
purchase from the NBS Office of Standard Reference Materials. Work
under this agreement is coordinated by the Office of Monitoring
Systems and Quality Assurance in EPA and by the Office of
Environmental Measurements in NBS and questions concerning this
program should be addressed to the Office of Environmental Measure-
ments, National Bureau of Standards, Washington, DC 20234.
WILLIAM H. KIRCHHOFF, Chief
Office of Environmental Measurements
ill
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ABSTRACT
A survey is presented on the research and development needs for personal
monitoring devices for toxic organic compounds in the ambient atmosphere.
This survey includes a description of organic compounds and their ambient
concentrations in the atmosphere, individual compounds of high priority, a
summary of a literature survey, a description of commercially available
workplace samplers, a summary of recent developments in ambient personal
monitoring and recommendations on major research needs. The high priority
compounds identified were predominately volatile chlorinated organics and
consist of the following compounds: methyl chloride, dichloromethane,
benzene, carbon tetrachloride, chloroform, dichlorobenzenes, 1,2-dichloro-
ethane, methyl chloroform, trichloroethylene and perchloroethylene. The
literature survey covers the period, 1974-79, and describes sorbent materials
for organic sampling, analytical procedures, and developments on personal
monitoring devices. The literature is predominately concerned with personal
sampling in the workplace environment. Commercially available personal
samplers described are Dupont's Pro-Tek organic vapor badge, Abcor's gasbadge,
3-M's organic vapor monitor and the Minimonitor (P. W. West, Louisiana State
University). Recent activities include a description of an EPA sponsored
program at Monsanto Research Corporation on development of personal samplers
for organics in the ambient atmosphere. Monsanto has developed an active
sampler consisting of a miniature pump with three sorbents in series - Tenax
GC, Poropak-R and Ambersorb XE-349. A description is also given of several
recent field studies on sampling and analysis for benzene and chlorinated
hydrocarbons in the ambient atmosphere. The survey concludes with recommenda-
tions for research and development activities in the following areas: evalua-
tion of sorbent materials, development of analytical techniques based on
electron capture-gas chromatography, evaluation of available active and
passive samplers on the high priority compounds, development of passive
samplers and development of standard mixtures for evaluation and calibration
of personal exposure devices.
iv
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CONTENTS
Foreword ill
Abstract iv
Tables vi
1. Introduction 1
2. Organic Compounds in the Atmosphere 2
3. Monitoring Needs 4
4. Survey of Organic Personal Exposure Devices 11
Summary of the Literature 11
Commercially Available Samplers 14
Conclusions 16
5. Summary of Recent Activities 17
6. Recommendations for Research and Development Activities . . 20
References 23
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TABLES
Number Page
1 Organic Compounds in the Atmosphere 3
2 General Sorption-desorption Systems for Organic Compounds ... 8
3 TSCA Priority List 10
4 Volatile Organic Compounds of Atmospheric Concern 13
vi
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SECTION 1
INTRODUCTION
Regulatory decisions on air pollution control, which involve direct and
indirect costs of billions of dollars, should be based on an adequate knowl-
edge of the health impacts of air pollution. A weak link in health effects
studies is our knowledge of individual exposures. The importance of popula-
tion exposure estimates in air pollution health effects studies makes it
imperative that future studies include estimates more representative of what
people breathe. Studies of air pollution health effects have usually relied
on one or several fixed monitoring stations to provide data for an estimate
of the exposure received by an entire neighborhood. Epidemiologists have
begun to call for something better. Several recent meetings of specialists
in the field of air pollution health effects have led to recommendations
urging the prompt development of small, portable individual air pollution
monitors (1).
In response to this need and under a EPA-NBS Interagency Agreement, the
NBS program is to develop principles and concepts and actual devices for
determining personal exposure to critical air pollutants. Both passive and
active monitors will be developed to provide long-term integrated exposures
(> 24 hours) and data on short-term exposure events (< 1 hour). During the
first year of the program the pollutants EPA has identified as having the
highest priority are fine particulates, nitrogen dioxide and toxic organics.
Because limited information for personal exposure devices for toxic
organics was available at the beginning of this program, the work reported
here is a survey of the research needs and promising approaches for develop-
mental activities.
In the following discussion we will present a description of the classes
of organic compounds present in ambient air and typical concentration levels,
monitoring needs as perceived from regulations and agency programs, a summary
of a literature survey, a description of commercially available workplace
devices, a summary of some recent activities on personal exposure devices for
ambient organics and recommendations of major research needs in this field.
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SECTION 2
ORGANIC COMPOUNDS IN THE ATMOSPHERE
Organic compounds are emitted into the atmosphere as a result of bio-
genie and anthropogenic activities. The most abundant single organic
compound in the atmosphere, methane (CHij) , results predominantly from micro-
biological processes, e.g., dead plant decay, and has a natural tropospheric
background concentration of ca. 1.4 ppm. Another major natural class of
organic component is the terpenes, which are emitted by many living plant
species. Other known natural gaseous organic compounds in the atmosphere
include organic mercaptans and sulfides and methyl iodide (2). Many of the
other organic compound emissions into the atmosphere are a result of anthro-
pogenic activities. A major source is motor vehicle emissions with other
significant contributions from stationary fuel combustion, solvent evaporation,
solid waste disposal, gasoline marketing and forest fires (2). Thus the
major urban anthropogenic organic class is hydrocarbons, of which the total
concentration may range from background (ca. 1.4 ppm) up to a few parts per
million by volume.
The presence of anthropogenic hydrocarbons in the atmosphere may contri-
bute to adverse environmental consequences. The non-methane hydrocarbons
(NMHC) are reactive in the presence of solar radiation and oxides of nitrogen
(from combustion in mobile and stationary sources) and promote elevated
levels of tropospheric ozone (03) and photochemical smog (3,4). Halogenated
hydrocarbons, in particular the freons, are so stable in the lower atmosphere
that they accumulate and diffuse into the stratosphere. Their photodegrada-
tion products destroy 03 and these compounds thus may pose a long-term threat
to the protective stratospheric 03 layer (5-8). Other organic compounds are
of concern because they pose a direct toxic threat when inhaled. For example,
emissions of vinyl chloride (9) and benzene (10) are controlled by federal
regulation because of the demonstrated health effects of these compounds (11-
13).
A detailed compilation of organic compounds, with ranges of concentra-
tion known to be present in the polluted troposphere, has been given in the
excellent monograph by Graedel (14). The classes of compounds compiled
include hydrocarbons, carbonyl compounds, oxygenated organic compounds,
nitrogen-containing organic compounds, sulfur-containing organic compounds,
organic halogenated compounds and organometallic compounds. Table 1 shows
some of these classes and their more prominent members with ranges of con-
centration.
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TABLE 1. CHEMICAL COMPOUNDS IN THE ATMOSPHERE AND AMBIENT CONCENTRATIONS.
Name
Alkanes (total)
Methane
Ethene
Terpenes (total)
Cyclic Hydro-
carbons (total)
Cyclohexane
Toluene
Benzene
m-Xylene
Naphthalene
Pyrene
Benzo[a]pyrene
Aldehydes +
Ketones (total
oxygen compound)
Formaldehyde
Concentration
1400 - 6000 ppb
1300 - 4000 ppb
0.7 - 700 ppb
0.1-1 ppb
2-50 ppb
Name
Acrolein
Acetone
Formic Acid
Esters (total)
Quinones
Concentration
1-13 ppb
0.08 - 6.8 ppb
4-72 ppb
1 - 100 ppb
<0.001 - 0.02 ppb
3 -
0.005 -
0.025 -
1 -
<0.001 -
<0.001 -
<0.001 -
1 -
1 -
6 ppb
129 ppb
57 ppb
61 ppb
0.06 ppb
0.02 ppb
0.008 ppb
200 ppb
160 ppb
Methanol
Phenol
Halogen Compounds
Methyl Chloride
Chloroform
Carbon Tetrachloride
Trichloroethylene
Vinyl Chloride
Halogenated Aromatics
Cyanogen
Sulfur Compounds
8 - 100 ppb
2.8 ppb
0.8 - 3.0 ppb
0.8 - 2.2 ppb
0.004 - 0.25 ppb
0.001 - 0.26 ppb
0.01 - 0.35 ppb
.005 ppb
^0.08 ppb
10 - 20 ppb
4 ppb
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SECTION 3
MONITORING NEEDS
It is obvious from the discussion in Section 2 above that there is a
wide variety of classes of organic compounds with many individual members
present in a polluted atmosphere. These compounds represent a wide range of
volatilities, polarities, and functionalities-properties which will surely
determine the choice of the sampling medium for a given compound or class of
compounds. In addition, the analytical work-up will vary for different
classes of compounds with different chemical and physical properties.
Finally, the most important factor to consider in determining monitoring
needs is the potential health threat, a factor which may range from none to
acute over the range of compounds found in the atmosphere. The potential
health threat of an organic compound is in turn determined by its degree of
toxicity, carcinogenicity or mutagenicity, production rate, emission rate
into the atmosphere, and its atmospheric persistence or lifetime.
In order to begin a program on development of personal exposure devices,
the identification of a finite set of organic compounds (classes) of high
priority based on potential health threat is required. Once this set of com-
pounds is identified, candidate sampling methods and analytical work-ups can
be chosen for development and evaluation. Our approach in identifying high
priority monitoring needs has been to a) examine federal regulations relative
to toxic organics in the atmosphere; b) survey documented information on high
priority toxic organics and c) consult with EPA personnel on high priority
agency programs on toxic organics.
The EPA is the federal agency with responsibility for the control of
emissions of toxic organics into the atmosphere. The EPA has several regula-
tory options available to carry out congressionally mandated emission control.
The Clean Air Act (15) as amended by the Clean Air Amendments (CAA) of 1970
and 1977 provides several options for control. Those options which have
resulted in regulations on organic compounds include 1) National Ambient Air
Quality Standards (NAAOS)/State Implementation Plans; 2) National Emission
Standards for Hazardous Air Pollutants, 3) New Source Standards of Performance
and 4) National Emission Standards for Mobil Sources.
Another major piece of legislation relative to control of organic com-
pounds in the environment is the Toxic Substances Control Act (TSCA) of 1976
(16). The TSCA enables EPA to gather from industry the required information
on any organic chemical produced as needed to determine its potential for
damaging human health and the environment, and to control them where necessary
to protect the public.
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THE CLEAN AIR ACT
Section 109 of the Clean Air Act requires that the Administrator set
national primary and secondary ambient air quality standards. Primary stan-
dard indicates those levels of air quality, including an adequate margin of
safety, which are necessary to protect public health. Secondary standards
indicate those levels which are necessary to protect public welfare from any
known or anticipated adverse effects. Public welfare includes effects on
vegetation, wildlife, physical properties of the atmosphere, materials, etc.
NAAQS have been set for particulate matter, sulfur oxides, nitrogen oxides,
photochemical oxidants, non-methane hydrocarbons (NMHC), and carbon monoxide
(17).
Standards are based on information from air quality criteria documents
prepared in accordance with section 108 of the Act. In addition, for each
criteria pollutant (a pollutant for which NAAQS are established), EPA must
prepare a document relating control techniques and costs of control. A pollu-
tant is considered a likely candidate for NAAQS if:
1. there is an adverse effect on public health or welfare
caused by the presence of the pollutant in the ambient
air, and
2. the presence of the pollutant in the air is the result
of numerous and diverse mobile and stationary sources.
To insure that levels indicated by NAAQS are attained, section 110 of the
Act requires States to submit Implementation Plans which demonstrate proce-
dures for attaining these standards. State plans must provide for attaining
primary standards within three years (a two-year extension may be requested),
and secondary standards within a reasonable time after approval of such a
plan.
The only regulation for organics under the NAAQS is on NMHC, i.e., total
hydrocarbon minus methane. It should be noted that although a standard exists
for NMHC, routine monitoring for NMHC is done in practice infrequently because
such a measurement is difficult to do accurately at ambient levels and because
the NMHC, as a class, is not directly associated with adverse health effects.
Rather the NMHC promotes the formation of 63 and other toxic components of
photochemical smog.
A potentially more important section of the Clean Air Act for the
regulation of organics is section 111, in particular lll(d). This section
requires EPA to set standards of performance on new or modified stationary
sources for any non-criteria air pollutant "which may reasonably be antici-
pated to endanger health or welfare".
Section 112 of the Act requires EPA to identify pollutants which cause an
increase in mortality or an increase in serious irreversible, or incapacitat-
ing reversible illness. These pollutants are generally considered to be less
ubiquitous pollutants covered by the NAAQS.
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For any pollutant which is considered hazardous, EPA must establish
emission standards which provide an ample margin of safety to protect public
health. In general, standards will be established by defining ambient guide-
line concentrations of a pollutant which provide an ample margin of safety to
protect health. Dispersion models are then used to determine the allowable
emissions that will ensure that the ambient guideline concentrations are not
exceeded. As presently written, the Act does not permit consideration of cost
or availability of demonstrated control technology in determining allowable
emissions. Hazardous emission standards have presently been promulgated for
the inorganics-mercury, asbestos, arsenic and beryllium and for the organics-
vinyl chloride (9) and benzene (10).
Section 202 of the Act requires the Administrator to set emission stan-
dards for any air pollutant coming from a motor vehicle if the pollutant is
harmful to public health and welfare. Mandatory emission reductions for CO,
total hydrocarbon (HC), and NO were written into the Act for light duty
X
vehicles. The Act required a 90 percent reduction in NO (N0+N09) to be
X £•
effective in 1976. These deadlines were subsequently extended to allow
vehicle manufacturers additional time to develop control systems.
In summary under the CAA, the only present regulations on organic
compounds are for NMHC under the NAAQS, for vinyl chloride and benzene as
hazardous pollutants, and for total hydrocarbons from vehicular emissions.
Of these only vinyl chloride and benzene are associated with direct health
effects and therefore should be considered with regard to personal monitoring
needs. It should be mentioned at this point that West (18,19) has developed
a permeation type, personal sampler for vinyl chloride.
THE TOXIC SUBSTANCES CONTROL ACT (TSCA)
The TSCA of 1976 is a comprehensive piece of legislation designed to
provide the information required to assess the potential health or environ-
mental threat from chemical substances. The TSCA also provides EPA with the
means for regulating the production, distribution, use and disposal of chemi-
cal substances when deemed necessary. A good summary of TSCA may be found in
reference (20). We only discuss here that aspect of the law which provides
information on toxic organics, which may be subject to regulation and which
may present needs for personal monitoring.
Section 4 on the "Testing of Chemical Substances and Mixtures" is perti-
nent to this discussion. Under this section EPA may require manufacturers or
processors to provide the test data required to determine whether chemicals
pose potential threats to health or the environment. Test data may be
required to characterize chemical substances in terms of their environmental
persistence and toxicity and to assess health and environmental effects
including carcinogenic, mutagenic, teratogenic, behavioral and synergestic
effects.
Section 4(e) establishes an Interagency committee to develop a "Priority
List" of chemicals to which EPA should give priority consideration for pro-
mulgating rules for obtaining test data. Among the relevant factors the
committee must consider in recommending this list are the following: 1) the
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quantity of the chemical substance manufactured; 2) the quantity which may
enter the environment; 3) the extent of human exposure to the chemical sub-
stance, and 4) the existence of data on the effects of the substance on health
and the environment.
The third factor is particularly important here in that it implies the
need for personal exposure studies. The Priority List may contain up to 50
chemical substances. The fourth report of this interagency committee to EPA
lists the latest Priority List of chemicals. This list of 33 individual
compounds or classes of compounds is reproduced in Table 2. It is of interest
to note that of these 33 substances, 30 are organic compounds or classes of
compounds.
While we regard the TSCA Priority List to be the comprehensive source in
identifying monitoring needs for specific organics or classes, some other
sources of information were examined. The Monsanto Corporation has recently
conducted a study for EPA which resulted in the identification of 20 high
priority atmospheric carcinogens from a list of 125 high volume chemicals
having the potential of becoming airborne pollutants (21). This prioriti-
zation was based on a rating scale which for each compound included the
emission rate, the atmospheric persistence and the potency relative to benzo-
(a)pyrene.
The chemicals on the list in a prioritized ranking are: benzo(a)pyrene,
tetrachloroethylene, ethylene dichloride, benzene, carbon tetrachloride,
ethylene dibromide, toluene-3,4-diamine, dioxane, acrylonitrile, ethylenimine,
benzyl chloride, benzidine, pentachlorophenol, dichloropropene, styrene,
hexachlorobutadiene, di-(2-ethylhexyl)phthalate, vinyl acetate, ethylene
oxide, and acrolein.
Both the TSCA Priority List and the Monsanto list include toxic compounds
of concern, whether their release into the environment occurs through the
aqueous, terrestrial or atmospheric media. We are concerned here about organic
substances which are released into and may persist in the atmosphere. We are
further concerned here for personal monitoring needs for vapor phase organics
in the atmosphere. Many of the toxic organics on the previous lists would
occur in the particulate phase if they persist in the atmosphere e.g.,
benzo(a)pyrene. A separate task of this same Interagency Agreement is con-
cerned with the personal sampling and analysis of pollutants in the particu-
late phase. Therefore, these lists were culled to eliminate those compounds
with low vapor pressure or high atmospheric reactivity with the OH radical or
03. The upper limit chosen for vapor pressure was the boiling point (ca. 180
°C) of the dichlorobenzenes, which have actually been observed in field
studies as discussed below.
For atmospheric reactivity, compounds with a half-life less than one week
based on reaction with OH radicals were eliminated. A mean tropospheric OH
concentration of 5 x 105 molecules/cm3 was chosen and the rate constants were
taken from the recent review of Atkinson (22). The choice of one week is
somewhat arbitrary, but it does provide a clean dividing line between the
chlorinated compounds and the other organics, with the exception of benzene.
For example, toluene and the cresols have half-lives of 3.8 and 0.5 days,
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TABLE 2. TSCA PRIORITY LIST
Acetonitrile
Acrylamide
Alkyl epoxides
Alkyl phthalates
Aniline and bromo, chloro and/or nitroanilines
Antimony (metal)
Antimony sulfide
Antimony trioxide
Aryl phosphates
Chlorinated benzenes, mono and di-
Chlorinated benzenes, tri, tetra and penta-
Chlorinated naphthalenes
Chlorinated paraffins
Chloromethane
Cresols
Dichloromethane
1,2-Dichloropropane
Cyclohexanone
Glycidol and its derivatives
Halogenated alkyl epoxides
Hexachloro-1,3-butadiene
Hexachlorocyclopentadiene
Isophorone
Mesityl oxide
4,4-Methylenedianiline
Methyl ethyl ketone
Methyl isobutyl ketone
Nitrobenzene
Polychlorinated terphenyls
Pyridine
Toluene
111-trichloroethane
Xylenes
8
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respectively, whereas methyl chloride and carbon tetrachloride have half-lives
of 1.6 years and greater than 65 years, respectively. Benzene is included on
this criterion in that its half-life is 16.5 days. If the criterion chosen
had been 1 day instead of 7, a few additional compounds, such as toluene and
methyl isobutyl ketone (T * 1.7 days), would have been, included but not many.
Rate data with OH were not available for some of the compounds and most
of these were compounds on the Monsanto list containing the vinyl grouping. A
reaction half-life of 10 days with 03 was estimated for these compounds using
10 18cm3s 1 for the rate constant (23) and a mean urban 63 concentration of
1012cm~3 (0.05 ppm). Since it is highly probable that the reaction half-life
with OH is less than that with 03, these compounds were not included. A few
compounds remained with no OH or 03 rate data (e.g., acetonitrile, pyridine
and ethylene oxide) but these were not included because of their probable
atmospheric reactivity.
The remaining compounds are shown in columns 1 and 2 of Table 3. This
table also lists two other sets of toxic organics which are based on current
EPA programs. Column 3 lists nine organic compounds found at elevated
concentrations during a recent EPA field survey in four different urban areas,
New Orleans, Houston, Niagara Falls, and Newark (24a). These compounds are
included in an extensive 3-year study—The Total Exposure Assessment Method-
ology (TEAM) Study—being mounted by EPA to obtain personal exposure data
(24b). Column 4 lists the eight toxic organic compounds for which EPA has
requested that NBS provide gas standards under a separate task of this same
Interagency Agreement.
There are two obvious conclusions which can be drawn from this Table.
The first is that there is considerable overlap among these lists of high
priority organic compounds. The second is that the Table predominately con-
sists of low molecular weight, halogenated organic compounds.
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TABLE 3. VOLATILE ORGANIC COMPOUNDS OF ATMOSPHERIC INTEREST
TSCA
Methyl Chloride
Mono/dichlorobenzenes
Dichloromethane
1,2-dichloropropane
Methylchloroform
MONSANTO
Benzene
Carbon Tetrachloride
Ethylene Dibromide
Ethylene Bichloride
Perchloroethylene
EPA
FIELD STUDY
Benzene
Carbon Tetrachloride
Chloroform
Dichlorobenzenes
1,2-dichloroethane
Ethylene Dichloride
Methylchloroform
Perchloroethylene
Trichloroethylene
ORGANIC
STANDARDS
Benzene
Carbon Tetrachloride
Chloroform
Ethylene Dibromide
Ethylene Dichloride
Perchloroethylene
Trichloroethylene
From TSCA Priority List.
From Monsanto Priority List, Reference 21.
-»
'Ubiquitous Ambient Organics Included in two EPA Field Studies, Reference 24.
Organic Standards Being Prepared for EPA Under Same Interagency Agreement.
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SECTION 4
SURVEY OF ORGANIC PERSONAL EXPOSURE MONITORS
SUMMARY OF LITERATURE SURVEY
A literature survey on sampling and analytical methods for detection of
toxic organics at ambient levels is a part of the EPA-NBS project. Little
work has been done to this date on personal exposure devices for toxic or-
ganics at ambient levels. The aim of this work is to evaluate the recent
developments on performances of several sorbents as collection media for the
quantitative concentration and analysis of volatile, hazardous vapor-phase
compounds from the ambient atmosphere. A brief summary on commercial monitor-
ing devices is also included.
The literature in this survey covers the five year period (1974 - 1979).
It is appropriate at this point that the open literature and EPA reports on
classes and ranges of concentration of hazardous organic compound present in
the urban and non-urban ambient air should be considered first. The survey
below discusses the solid sorbents and analytical techniques which have been
used, as well as developments on sampling devices (dosimeters).
Activated carbon has been selected and used by NIOSH for collecting
organic vapors (26,27). However, the detrimental effects caused by water and
the reactivity of collected samples with charcoal, dictates the evaluation of
alternative solid adsorbents. The criteria for the evaluation of methods for
the collection of organic pollutants in air using solid sorbents is a subject
of several recent papers (28,29,30), a monograph by NIOSH (31) and a recent
EPA monograph (32); the analytical methods for organic pollutants have been
recently discussed at length by NIOSH (33).
A recent evaluation (34) of solid sorbent materials for sampling organic
vapors indicated three major classes: 1) porous polymers (e.g., Tenax-GC,
Porapaks, Chromosorbs); 2) carbonaceous materials (activated carbons, char-
coals, graphitized carbon black, Ambersorbs); and 3) others (e.g., molecular
sieves, silica gel, liquid-coated solid supports).
The porous polymers were found (34-37) to have the most desirable prop-
erties for air sampling, having low background and low reactivity as well as
high capacities for many compounds. However, the porous polymers were found
to have little capacity for the more volatile compounds. The carbonaceous
materials were noted to have much better capacities for volatile compounds,
but are plagued with reactivity problems and susceptibility to water vapor
(hydrophylicity).
11
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The additional advantages for sampling of organic pollutants with porous
polymer sorbents are high selectivity, ease of sample handling and ability to
analyze polar materials not recoverable from charcoal (38); more on the
subject is reported elsewhere (39-42). After a thorough evaluation of five
major solid sorbents, three were selected for future consideration for use in
a miniature air sampling system (34).
Tenax. The only high-temperature (400 °C) adsorbent available which
allows the quantitative thermal desorption of low-volatility organic compounds.
Porapak R. One of the highest-capacity polymeric adsorbents with an
overlap in range of utility with Tenax-GC.
Ambersorb XE-340. Anticipated for the desorption of compounds of inter-
mediate volatility; more stable than charcoal towards water vapor.
By an independent study (43), Tenax-GC was found to be superior to other
sorbents as a collection medium for volatile, hazardous, vapor-phase com-
pounds from the ambient atmosphere. The effects of humidity, background air
pollution, repeated re-use of sorbent, and transportation and storage of
collected samples were also investigated. The general sorption-desorption
systems for organic compounds in regard to the most used sorbents, desorption
solvents and the types of compounds collected is summarized in Table 4.
Evaluation of a technique for sampling low concentrations of organic vapors
in ambient air is a topic of a recent paper (44).
Many analytical techniques have been applied to the identification and
quantitation of organic compounds in ambient environmental media. In effec-
tive measurement of the ambient concentration of a toxic material in air, the
following steps are involved a) collecting the sample (sorbent medium, e.g.
Tenax-GC, carbon, chromosorb, etc.); b) extracting the components of interest
from the sample; c) concentrating the extract, and d) injecting the sample
into a gas chromatograph coupled to a suitable detector. A combined tech-
nique of capillary gas chromatography with mass spectrometry has been recently
applied for analysis of air pollutants (45). A NIOSH Manual of Analytical
Methods has also been published (33) . A recent book (46) discusses in detail
the chemistry sources, sampling and collection of air pollutants, as well as
the analysis of pollutants by instrumental methods.
In 1970, the Occupational Safety and Health Administration (OSHA) devel-
oped standards to protect employees against the potentially harmful effects
of approximately 400 chemicals (20,26). This set of standards is routinely
reviewed and updated as more and more clinical information on the physiolog-
ical impact of these chemicals became available. When these occupational
standards were first published, the recommended sampling method for organic
vapors was the charcoal tube method.
The charcoal tube method was originally selected by NIOSH and recom-
mended as the referee sampling method for organic vapors (26,51,61). The
method involves pumping of a known volume of air through a charcoal packed
tube for a measured period of time (the charcoal serves as an adsorbent for
organic vapors). The charcoal is then extracted with an appropriate solvent
12
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TABLE 4. GENERAL SORPTION-DESORPTION SYSTEMS FOR ORGANIC COMPOUNDS.
Sorbent
Activated
carbon
Desorption Solvent
Carbon disulflde
dichloromethane
ether (1% methanol
or 5% isopropyl
alcohol sometimes
added)
Types of Compounds
Misc. volatile organics:
methyl chloride, vinyl
chloride, and other chlori-
nated aliphatics, aliphatic
and aromatic solvents,
acetates, ketones, alcohols,
etc.
Silica gel
Methanol, ethanol
diethyl ether,
water
Polar compounds:
alcohols, phenols, chloro-
phenols, chlorobenzenes,
aliphatic and aromatic
amines
Activated alumina
Water, diethyl
ether, methanol
Polar compounds:
alcohols, glycols, ketones,
aldehydes, etc.
Porous polymers
Ether, hexane,
carbon disulfide,
alcohols
Wide range of compounds:
phenols, acidic and basic
organics, multi-functional
organics, etc.
Chemically bonded
and other GC
packings
Ether, hexane,
methanol
Specialized high boiling
compounds, pesticides,
herbicides, polynuclear
aromatics, etc.
Thermal Desorption None
Misc. volatile organics,
halogenated organics,
hydrocarbons, aromatics, etc.
13
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(usually carbon disulfide) and the extractant analyzed with a gas chromatog-
raph. The major disadvantage of this method is that it employs personal
sampling pumps, which can weigh up to 2 pounds each.
Recently several Industrial companies introduced a new type of air
sampler, the passive organic vapor dosimeter, which can replace the charcoal
tube. This dosimeter also relies on the ability of charcoal to selectively
adsorb organic vapors, but differs in that the vapors enter the sampler by
molecular diffusion or permeation rather than by mechanical means. Conse-
quently, the dosimeter requires no electrical power. Recent emphasis has
also been toward the development of portable personnel dosimeters which could
be used up to eight hours to determine "time-weighted-average" (TWA) exposures.
For example, current standards for vinyl chloride vapor (9,47) call for an
action level of 0.5 ppm TWA exposure, which if exceeded, requires the imple-
mentation of an extensive personal monitoring program. This directive (9,47)
permits a maximum allowable 8-hr TWA exposure of 1 ppm to vinyl chloride and
a maximum permissible exposure of 5 ppm for no more than 15 min. A method
for measuring the exposure of personnel to vinyl chloride has been developed
which utilizes the permeation technique for sampling (18).
The abundant literature on the development strategy for pollution
dosimetry is a subject of several papers, monographs, and books (25,32,46,48-
59).
COMMERCIALLY AVAILABLE SAMPLERS
Several types of badge-size devices for monitoring individual exposure
to hazardous organics at ambient concentrations now are being produced by
several industrial companies. These types of samplers are passive and are
worn on the clothing as small badges. By definition, a passive personal
monitor is a device worn on an individual for the purpose of measuring -
without the use of an active flow device - personal exposure (61). There are
several advantages to passive monitors (badges); they are small, lightweight,
and easily worn by any individual. The badge uses the principle of diffusion
or permeation of the organic vapor through a membrane to a charcoal sorbent.
The badges, however, are not without disadvantages - e.g. high humidity
alters the adsorption of various organic vapors on charcoal. It is not yet
apparent what can be done to correct for high humidity effects in passive
monitors with charcoal sorbent (61). Commercially available passive organic
samplers include DuPont's Pro-Tek badge, Abcor's gasbadge, 3-M's organic
vapor monitor and the Minimonitor (P. W. West).
Recently DuPont's Applied Technology Division (62-64) introduced an
inexpensive and very light (7.7 g) Pro-Tek pollution-monitoring badge for
hazardous organics. The organic vapor monitoring system is designed around a
small strip having 300 mg of activated charcoal contained in a rectangular
envelope perforated with a known number of accurately sized pores. After
activating the badge by removing impervious covers from the pores, the
contaminants diffuse through the pores and are adsorbed on the charcoal. The
badge can be deactivated by replacing the impervious strips. Two sampling
rates, 50 cc per minute and 100 cc per minute, can be selected by using one
or both sides of the badge. Each side has an impervious cover over the
porous badge.
14
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To analyze for contaminants, the charcoal strip is removed and placed in
a vial containing a set amount of solvent (e.g. carbon disulfide). The
solvent extracts the contaminants from the charcoal strip, and analysis is
performed by conventional gas chromatography. The manufacturer claims this
badge to be virtually independent of pressure effects and that it is only
slightly affected by temperature and ambient air velocity.
Depending on the organic contaminants adsorbed by the charcoal, the
sampling range varies between 0.2 ppm-hour and 2000 ppm-hours. The desorp-
tion efficiency for common vapors, such as benzene, toluene, and carbon
tetrachloride, is between 95 and 100 percent. Larger molecules, e.g., more
polar compounds, such as acrylonitrile, show smaller desorption efficiencies,
but they are well within NIOSH requirements and give reproducible results.
The passage of the vapors through the pores is controlled strictly by molec-
ular diffusion, and diffusion coefficients of various vapors duplicate the
accepted literature values for these vapors (62). The detection limit claimed
for benzene is 0.20 - 0.25 ppm (64).
The Abcor Gasbadge is 6.5 cm long, 5.1 cm wide, and 1.6 cm thick. It
weighs approximately 43 g and consists of seven parts: the sliding cover;
the front plate of the badge, which has a 4.4 cm x 3 cm opening to allow
diffusion of gases; a protective screen; a draft shield; an open grid that
defines the diffusion geometry; the collection element (activated carbon);
and the back plate of the badge. The Gasbadge is reusable by replacing the
collection element. This dosimeter, which comes in two sizes, also relies on
the ability of charcoal to selectively adsorb organic vapors and collection
of the vapors by molecular diffusion rather than by mechanical means. The
charcoal is solvent extracted and the extractant analyzed with a gas chroma-
tograph. The Gasbadge specifications claim: sampling time - 8 hr nominal;
sampling range - 0.2-160 ppm/8 hr TWA (benzene); accuracy - ± 25 percent at
0.2 ppm for benzene (65,66); shelf-life - 2 years.
The 3-M Organic Vapor Monitor is an oblong badge which is 10.2 cm long
(including the clip), 4.4 cm wide at its widest point, and 1.2 cm thick. The
sampling opening is circular with a 3 mm diameter. This badge weighs 13.5 g.
During sampling, the unit consists of six pieces: the outer rim; the draft
shield, which is held in place by the outer rim; an open grid that defines
the diffusion geometry; the collection element; and the solid back piece of
the monitor. The sixth piece is a clip for attachment to the person. The
3-M passive monitor allows for -in situ sample elution. The Aldrich Chemical
Company, Inc. (Milwaukee, Wisconsin) is a sale representative for the 3-M
Organic Vapor badge.
The MiniMonitor, which was developed by Philip West at the Louisiana
State University, is a circular badge. Its diameter is 5.0 cm, it is 0.625
cm thick and weighs 35 g. A feature unique to the MiniMonitor is that the
badge works on the principle of permeation of contaminant gases through a
membrane, followed by adsorption of the pollutant(s) onto approximately 1.35
g of PCB activated charcoal. The MiniMonitor case is reusable by introducing
a fresh supply of charcoal.
15
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CONCLUSIONS
The minimum detection limits of badges with activated carbon adsorbents
could be reduced into the parts-per-billion range (10-20 ppb) by increasing
sampling rate by a factor of two or more. Also, the sensitivity of charcoal
badges may be improved considerably by eliminating or reducing the background
adsorption, i.e., trace impurities adsorbed prior to sampling.
NIOSH is planning to look further into the use of passive monitors by
testing different solid sorbents as the collection element and perhaps eval-
uating electrochemical detection techniques. As far as their application to
ambient personal monitoring goes, the available passive monitors have some
major drawbacks: 1) the monitors generally lack specificity (a drawback of
some other sampling techniques as well); and 2) the detection limits of the
monitors—at the low end of the scale—may not meet the needs of ambient
sampling. While it is true that collection on the element is an enrichment
step, it could take a long time to accumulate a detectable sample from
ambient air. With certain new products that are coming out, (e.g., porous
beads or porous polymers) and as the technology (e.g., electrochemical detec-
tion) allows us to develop more effective procedures, passive monitoring
should be feasible in the ambient atmosphere.
16
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SECTION 5
SUMMARY OF RECENT ACTIVITIES
The literature survey in Section 4 and the discussion on commercially
available samplers is almost totally concerned with personal exposure
sampling in the work-place atmosphere. Pollutant concentrations of concern
are in the part-per-million range (ppm) and the best minimum detectable
limits for the samplers discussed above are a few tenths of a ppm for 8-24
hour sampling. It is obvious from Section 2 (see Table 1) that the concen-
trations of individual toxic organic compounds in ambient air will be in the
part-per-trillion (ppt) range or 2-3 orders of magnitude less than in the
work-place atmosphere. Since the pumping speeds available would be about the
same for ambient personal sampling as work-place sampling, the total amount
of sample collected for the ambient case would be 2-3 orders of magnitude
less than for work-place sampling. We can expect then that there will be
quite different and/or more difficult problems associated with ambient
sampling. The published literature yields little information on personal
sampling for toxic organics in the atmosphere. There is some, as yet
unpublished, information on recent activities in personal sampling for
organics which is discussed below.
For the past two years, the Monsanto Corporation has conducted a research
program to develop a portable, miniature, sorbent-based sampler and the
associated analytical technology for the purpose of assessing individual
exposure to toxic (primarily carcinogenic) compounds (67,68). The program
consists of three phases: 1) evaluation and selection of sorbent materials
and sampler design; 2) laboratory development of a prototype sampler and
development of analytical methodology, which is capillary gas chromatography/
mass spectrometry (GC/MS); and 3) field evaluation of the system in selected
urban areas. The first two phases of this program are essentially complete.
From a survey of a wide variety of commercially available sorbent
materials 1) porous polymers, e.g., Tenax-GC, Poropak, Chromosorbs; 2) carbo-
naceous materials, e.g., activated carbons, Ambersorbs, and 3) others, e.g.,
molecular sieves, silica gel, five were selected by Monsanto for detailed
evaluation. These five were Tenax-GC, Poropak-N, Poropak-R, Ambersorb XE-
340, and SKC activated charcoal. These five were selected because they have
the potential to sample compounds which have a wide range of polarities and
volatilities. These sorbents were evaluated with a matrix of 18 organic test
compounds representing a wide range of volatilities, polarities and func-
tionalities. With these compounds the 5 sorbents were evaluated with respect
to capacity, desorption efficiency (thermal desorption), background, decom-
position and pressure drop. The three sorbents finally selected were Tenax-
GC, Poropak-R, and Ambersorb XE-340 for the collection of low volatility,
intermediate volatility and high volatility compounds, respectively.
17
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Poropak-R was chosen over Poropak-N because it gave a much better background
in the GC/MS analysis. Ambersorb XE-340 was chosen because of "less diffi-
culty anticipated with desorption and fewer detrimental effects by water and
reactivity with collected samples (68).
The sampler designed by Monsanto consists of three tapered glass tubes,
each containing 1-2 grams of the sorbent, arranged in series, followed by a
flow control device and ending with a portable miniature pump.
Considerable progress has also been made in developing the associated
GC/MS analytical technology. The Monsanto personnel have estimated detection
limits of 1-10 ppt for a variety of organic compounds for a 480 liter sample
(1 L/min. for 8 hr.). This is based on an assumed detection limit of 10
nanograms (ng) for capillary column GC/MS (69).
Pellizzari has reported favorable results with the use of Tenax-GC as
the sorbent in a glass tube sampler for a wide variety of organic compounds
which may be present in ambient air (43,70, 71). Among the advantages of
Tenax-GC were high collection efficiencies, good thermal desorption efficien-
cies with low attendant background up to 300 °C, the absence of any effects
from variable atmospheric humidity, and good storage properties. The only
apparent drawback is low capacity or low breakthrough volume (in liters air
per gram of sorbent) for highly volatile organics. Compounds with a vapor
pressure greater than about chloroform (b.p. = 61 °C) can not be collected
efficiently. This would rule out Tenax-GC for the collection of compounds
such as methyl chloride and dichloromethane, which are on the TSCA Priority
List.
Activated carbons should have the efficiency required for the collection
of the highly volatile organics (68). However Pellizzari reports (71),
and the Monsanto report (68) implies, that quantitative thermal desorption
cannot be achieved for ambient samples of organics on activated carbons.
Solvent desorption may work for the activated charcoals, and this is the
technique commonly used in NIOSH procedures. However, the amount of any
individual ambient organic collected in a miniature sampler will be small for
a normal sampling volume, e.g., 1-100 ng. Elution of this amount would
result in a very dilute solution of a very volatile organic and quantitative
concentration of the solution would be difficult. Since only an aliquot of
this dilute solution could be used for the GC analysis, the overall sensi-
tivity of the method would be reduced to the point that may probably be
inadequate for ambient analysis. Brooks and West (72) have recently encoun-
tered just this problem in attempting to analyze for a number of volatile
organics adsorbed on Ambersorb XE-340 by solvent extraction.
We are aware of only two field studies utilizing miniature personal
samplers. The first is an unpublished'study by Pellizzari, et al. (73).
This study utilized a glass tube cartridge with Tenax-GC as sorbent and a MSA
miniature pump for the personal sampling of benzene in St. Louis and Houston.
The results of this study showed ambient levels of benzene in St. Louis which
could be correlated with source activities and ubiquitous levels of benzene
in the Houston area. The EPA TEAM study mentioned earlier has employed the
same personal samplers to measure 8-hour exposures of students at Lamar
18
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University in Texas and the University of North Carolina and also of the
general public in Research Triangle Park, N.C., and Elizabeth and Bayonne,
N.J. A dozen or more organic compounds were detected, with concentration
levels ranging from 0.1 to 100 ppb.
There have been several other recent field studies on ambient volatile
organics in which personal samplers were not used, but which are pertinent to
this report. An EPA study in Dallas, Chicago, and Los Angeles (74) utilized
a Tenax-GC sorbent, thermal desorption and GC-flame ionization analysis to
measure ambient concentrations of benzene. Levels observed were 5 yg/m3
(1.6 ppb) for Dallas, 18 yg/m3 (5.6 ppb) for Chicago and 19 yg/m3 (6.0 ppb)
for Los Angeles.
Another EPA study in New York City, Houston and Detroit utilized an
activated carbon sorbent, solvent elution with carbon disulfide and GC-
electron capture detection for the measurement of ambient levels of tetra-
chloroethylene (75). All the measurements in New York City gave values
greater than 0.1 ppb (the minimum detection limit), one-half were greater
than 1 ppb, and the maximum value observed was 10 ppb. In Houston and
Detroit, 90 percent of the measurements gave values less than 1 ppb. If
these results are valid, they would contradict the earlier statements on
recovery from charcoal and inadequate sensitivity using solvent extraction.
With regard to sensitivity these results may reflect the much greater sensi-
tivity of electron capture as opposed to flame ionization detection. We have
already alluded to the recent EPA study (24) in Houston, Niagara Falls,
Newark, and New Orleans in which volatile chlorinated organics and benzene
were consistently found. This study utilized 2 1/2 grams Tenax-GC in a glass
tube sampler, collection of ca. 100 liters total sample, thermal desorption
and GC/MS analysis.
19
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SECTION 6
RECOMMENDATIONS FOR RESEARCH AND DEVELOPMENT OF ACTIVITIES
We have presented below our concepts of all the major research and
development needs in the field of personal monitoring for toxic organics. We
would recommend top priority for the nine organics from column 3, Table 3
as well as methyl and methylene chloride from the TSCA priority list. With
the exception of benzene, these represent a single class of compounds -
volatile chlorinated organics with long atmospheric persistence. This also
presents the possibility of using highly sensitive electron capture (EC)
detection, again with the exception of benzene, in the GC analysis. This
could lead to greatly reduced requirements in terms of amount collected for
many of these compounds.
Research and development activities on personal monitoring for volatile
chlorinated organics are recommended in the following areas:
1. Evaluation of sorbent materials
2. Development of analytical techniques based gas chromatography with
electron capture and photoionization detection.
3. Evaluation of active samplers
4. Development and evaluation of passive samplers
5. Development of standard mixtures for evaluation and calibration of
personal exposure devices.
Tenax-GC has been shown to be an excellent sorbent for a wide variety of
organic compounds and exhibits such desirable properties as good collection
efficiencies, high operating temperature (350 °C) for thermal desorption,
with low background bleeding and a low retentive index for water (43).
However we have seen little documentation on the use of Tenax-GC for the
collection of the particular chlorinated compounds discussed above. There-
fore Tenax-GC should be evaluated on these compounds with respect to collec-
tion efficiency, breakthrough volume and thermal desorption efficiency.
Brooks (76) reported a low breakthrough volume (< 1 L/g) for CCli+. As
indicated earlier, Tenax-GC would probably be inefficient for the collection
of the more volatile chlorinated organics such as chloromethanes. Other
sorbents should be evaluated such as Chromosorb 104, as suggested by Pellizzari
(43), or Poropak-R (68). Another possibility would be to attempt to develop
a porous polymer analogous to Tenax-GC, but with a greater capacity for
highly volatile compounds.
20
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Activated carbons and the carbonaceous material Ambersorb XE-340 should
collect the volatile chlorinated compounds, but thermal desorption is not
feasible for activated carbons and more work is required to determine
desorption efficiencies for Ambersorb XE-340. Some effort should be made to
study solvent desorption efficiency and to determine whether EC-GC would have
the required sensitivity with the resulting solutions.
Because of the inherent high sensitivity, EC-GC techniques should be
developed for the analysis of the chlorinated organics. Detection limits in
the range of 10~12 to lO"1** g are possible with EC detection (69). If a
chlorinated compound (M.W. = 100) with an atmosperic concentration of 1 ppt
is sampled at a rate of 1 L/min. for 8 hours (ca. 500 liters), the amount of
sample collected will be 2 x 10 9 g. If quantitative thermal desorption is
possible, this sample weight is still well above detection limits. On the
other hand, it would be well below the detection limits by flame ionization.
Since many chlorinated compounds are likely to be found in the ambient
atmosphere, the principal problem expected is chromatographic resolution.
This is an area which may require the most effort in terms of analytical
technique development. Recent developments in fused silica capillary column
technology should be investigated for improved resolution. The use of flame
ionization detection (FID) is likely the best approach for benzene and some
of the other chlorinated compounds with concentrations of 0.1 ppb or greater.
Photoionization detectors would provide greater sensitivity and applicability
to a broad range of organic compounds and should be evaluated.
Active sampling devices have been developed which may be amenable to
personal exposure studies. Pellizzari (73) has used a personal Tenax-GC
sorbent sampler in the field, and a multiple sorbent sampler has been devel-
oped by Monsanto (69). These samplers should be evaluated with volatile,
chlorinated organics with respect to collection efficiency, breakthrough
volumes, desorption efficiencies and tested under realistic field conditions.
The development of passive sampling devices for toxic organics at ambient
levels is a largely unexploited area and should be of considerable interest
in a longer out-put time frame. We are currently investigating some promis-
ing passive samplers for inorganic air pollutants at ambient levels (77) and
this technology should be applicable to the toxic organics. The primary
advantage of passive samplers is in their size, and possibly cost, in that
no pumps or other moving parts are required. The key to developing an
effective ambient passive sampler is in attaining a high equivalent passive
sampling rate. As discussed in the report on passive samplers for N02 (77),
this equivalent sampling rate (F ) is determined by the diffusion rate of
the pollutant to the collection medium and by sampler geometry,
F = D x A/S,
eq
where D = diffusion coefficient, cm2/s
A = area of diffusion barrier, cm2
H = length of diffusion barrier,
cm.
21
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Since the diffusion rate is constant for a particular diffusion medium and
pollutant, the sampling rate is strongly controlled by the geometry term,
A/£, which can conceivably be made quite large. For a passive membrane N02
sampler we are evaluating, the diffusion barrier is a thin circular silicone
membrane with an A/£ of ca. 500 (77). Other designs could conceivably further
increase this value. For example, a double sided membrane sampler with
substrate in between would double this value. A multilayered membrane
sampler may increase this rate by the number of layers. There are certainly
other design geometries whereby high area, thin film barriers can be struc-
tured within a small personal sampler, and this is an area which should be
explored. Some of the commercially available work place badge samplers have
sampling rates of 30-100 cm3/min. With a more creative design, sampling
rates equivalent to that of available miniature pumps (1 L/min.) should be
feasible.
There remains the question of the feasibility of using commercially
available dosimeter badges (Abcor, 3-M, Dupont) for sampling and analysis of
the volatile chlorinated organics. However, these badges use activated
charcoal as sorbent (the NIOSH method) and thermal desorption and direct
injection into the gas chromatograph apparently cannot be done with any
efficiency (68, 71). The NIOSH work place methods use solvent elution, but
much larger quantities of adsorbed pollutant are available. Nevertheless, we
should consider the case of elution of a typical chlorinated organic from
charcoal for EC-GC analysis.
Let us assume a hypothetical case using best estimates. A passive badge
with an equivalent sampling rate of 75 cm3/min. (a high value) would sample
100 liters of air in a 24 hour period. For a light chlorinated compound
(e.g., mw = 100) at a concentration of 100 ppt (0.1 ppb) , 4 x 10 8 g would be
adsorbed if the efficiency is 100 percent. Let's assume that this compound
can be eluted efficiently with 4 mL of solvent (a typical value) to yield a
solution with a concentration of 10 8 g/mL or 10 5 yg/yL. Injection of 1 yL
(a normal value) of this solution into the chromatograph corresponds to 10 **
g of the chlorinated compound. The detection limits of modern GC instruments
for chlorinated compounds are in the range of 10 12 - 10 1If g. Therefore the
compound should be detectable. There were several assumptions made above,
but this simple analysis does demonstrate that the commercial badges should
at least be evaluated for the volatile chlorinated compounds with EC-GC
analysis.
With regard to standard mixtures, NBS is already in the process of
developing standards for some of these chlorinated compounds (see Table 3).
These standards and the generation systems employed should be useful in the
evaluation and calibration of sampling devices considered here. Both cylinder
standards and permeation tube devices are being developed for the compounds
listed in column 4 of Table 3.
22
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37. Holzer, G., H. Shanfield, A. Zlatkis, W. Bertsch, P. Juarez, H. Mayfield,
and H. M. Liebich. Collection and Analysis of Trace Organic Emissions
from Natural Sources. J. Chromatogr., 142:755-764, 1977.
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41. Raymond, A., and G. Guiochon. J. Chromatog. Sci., 13:173-177, 1973.
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Abstr. 89:220155g.
45. Bursey, J. T., D. Smith et. al. American Laboratory, 9:35, 1977; Chem.
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76-03, February, 1976.
26
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57. Assessment of Benzene as a Potential Air Pollution Problem. Vol. IV,
GCA/Technology Division, Bedford, Massachusetts. Prepared for Environ-
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science, New York, N.Y., 1979.
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70. Pellizzari, E. D., J. E. Bunch, and B. H. Carpenter. Envir. Sci. Tech.,
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA 600/4-80-042
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Survey on Research Needs on Personal Samples
for Toxic Organic Compounds
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Jimmie A. Hodgeson and Alexander J. Fatiadi
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
National Bureau of Standards
Center for Analytical Chemistry
Washington, B.C. 20234
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
AD-13-F-0-034-0
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
Office of Research and Development
Office of Monitoring and Technical Support
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A survey is presented on the research and development needs for personal monitoring
devices for toxic organic compounds in the ambient atmosphere. This survey includes
a description of organic compounds and their ambient concentrations, individual
compounds of high priority, a summary of a literature survey, a description of
commercially available samplers, a summary of recent developments in ambient personal
monitoring and recommendations on major research needs. The high priority compounds
identified were: methyl choloride, dichloromethane, benzene, carbon tetrachloride,
chloroform, dichlorobenzenes, 1,2-dichloroethane, methyl chloroform, trichloroethylene
and perchloroethylene. The literature survey covers the period, 1974-79. Commercially
available personal samplers described are Dupont's Pro-Tek organic vapor badge, Abcor's
gasbadge, 3-M's organic vapor monitor and the Minimonitor (P.W. West, Louisiana State
University). Recent activities include a description of an EPA sponsored program at
Monsanto Research Corporation on development of personal samplers for organics. A
description is also given of several recent field studies on sampling and analysis
for benzene and chlorinated hydrocarbons. The survey concludes with recommendations
for research and development activities in the following areas: evaluation of sorbent
materials, development of analytical techniques based on electron capture-gas
chromatography, evaluation of available active and passive samplers, development of
passive samplers and development of standard mixtures for evaluation of personal
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Fieid/GlOUp
Ambient Atmosphere
Benezene
Cholorinated Hydrocarbons
Air Pollution Methodology
7C
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
35
20. SECURITY CLASS /Thispage)
Unclassified
22. PRICE
$6.50
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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