EPA-660/4-75-002
MAY 1975
Environmental Monitoring Series
Aqueous Odor Thresholds of Organic
Pollutants In Industrial Effluents
5
5SK
\
HI
(3
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Corvallis, Oregon 97330
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RESEARCH REPORTJN&-'SERIES
Research reports of the Office of Research and Development,
U.S. Environmental Protection Agency, have been grouped into
five series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in
related fields. The five series are:
T. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL MONITORING STUDIES
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.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement or
recommendation for use.
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EPA-660/4-75-002
MAY 1975
AQUEOUS ODOR THRESHOLDS OF ORGANIC POLLUTANTS
IN INDUSTRIAL EFFLUENTS
By
Dorris A. Li Hard
John J. Powers
Department of Food Science
University of Georgia
Athens, Georgia 30602
Grant No. R-802980-01
Program Element 1BA027
ROAP/Task No. 16ADN 64
Project Officer
Ronald G. Webb
Southeast Environmental Research Laboratory
National Environmental Research Center
Athens, Georgia 30601
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
Fot Sila by tho National Technical Information Service
U.S. Department of Commerce. Springfield, VA 22151
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ABSTRACT
This investigation was designed to determine the odor thresholds in
water of organic pollutants that have been identified in industrial
effluents. Seven to fourteen judges were used to determine the odor
threshold values of 13 compounds at room temperature and 60°C. Odor
threshold values for the compounds in ppm at room temperature are:
acenaphthene, 0.08; 2-ethyl-l-hexanol, 1.28; butanol, 2.77; geosmin,
0.13 x 10~3; 2-methyl naphthalene, 0.01; 1-methyl naphthalene, 0.02;
diacetone alcohol, 44.1; dibenzofuran, 0.12; 2-benzothiazole, 0.08;
2-mercaptobenzothiazole, 1.76; 2-ethyl-4-methyl-l,3-dioxolane, 0.38;
caprolactam, 59.7; d-camphor, 1.29. Extreme value calculations were
made to predict a concentration below which a certain percentage of
the population might still be able to detect the compound(s). The
threshold values obtained at 60°C in most cases do not differ or are
higher than those determined at room temperature.
This report was submitted in fulfillment of Project Number R802980-01
by the University of Georgia under the partial sponsorship of the
Environmental Protection Agency. Work was completed as of September
15, 1974.
ii
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CONTENTS
Page
Abstract 11
List of Tables Iv
Sections
I Conclusions 1
II Introduction 2
III Materials and Methods 4
IV Results and Discussion 6
V References 19
111
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TABLES
No. Page
1 Judges Response for the Odor Threshold of 7
Acenaphthene at Room Temperature
2 Odor Threshold Concentrations in Water of 8
Chemicals at Room Temperature
3 Odor Threshold Concentrations in Water of 9
Chemicals at 60°C
4 Concentrations of Chemicals that May be De- 13
tected by Various Segments of the Population
as Predicted by Extreme Value Calculations
5 Odor Threshold Concentrations of Chemicals 15
in Water
iv
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SECTION I
CONCLUSIONS
The detectable odor threshold in water of a compound was not the
same for all judges. Also, the judges' ability to detect odor
varied with the compounds being tested. A judge may be the most
sensitive to one compound and the least sensitive to another. Con-
ducting the odor threshold determinations at 60°C offers no advantage
over the determinations done at room temperature. Since it is im-
practical to determine odor thresholds using a large number of people,
it is best to use at least seven judges and by using extreme value
calculations on their results to determine the probability of people
being able to detect the odor at concentrations below the odor
threshold value of any compound.
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SECTION II
INTRODUCTION
GENERAL
Within the last few years, considerable interest has been placed on
the pollution of surface water by organic chemicals. In a recent
review, Zoeteman and Piet-*- reported that organic pollutants have
been traced to both industrial effluents and microorganism that grow
in surface water. Regardless of how the organic chemicals enter the
water, their presence can result in complaints about the taste and
odor of drinking water, as well as off-flavored fish harvested from
polluted streams and reduced aesthetic value of polluted rivers and
lakes that are used for recreation. Also, the extreme toxicity of
certain chemicals to aquatic species as well as man cannot be over-
looked. Fortunately for man, many organic chemicals can be detected
by the olfactory system before they reach toxic concentrations.
Advanced analytical techniques using gas chromatography-mass spectro-
metery have resulted in the identification of several hundred com-
pounds in water2»l. The complex nature of odor sensation and the
wide variability of people's ability to detect odor has slowed the
research effort on determining the odor threshold of organic chemicals
in water. Zoeteman and Piet reported that they were able to find
threshold concentrations for approximately 400 chemicals. Their
search of the literature also illustrated the wide discrepancies
among the threshold values for the same compounds as determined by
different investigators. This difference in threshold concentration,
which varied by a 1,000 fold for some compounds, may be due to the
different sensitivity of judges, the procedure used for threshold
determination or impurities in the compounds studied.
A number of procedures have been developed to measure the odor thres-
hold of compounds in water3»4,5,6,7. Baker^ evaluated several methods
of determining odor measurements and concluded that a triangle test
(based on a modification of the ASTM method of test, D1292) was
statistically the best procedure and was preferred by the panelists.
Rosen5* preferred the consistent series method since it minimized dis-
tractions and odor fatigue and yielded data with economy of time and
effort. Since each group has its own preferred method of determining
threshold concentration and may be biased in their evaluations, a
standard procedure for measuring thresholds should be developed by
evaluating several procedures on several compounds. This should be
a cooperative study among different laboratories that are conducting
odor threshold work. Regardless of the method used for their determi-
nation, threshold studies should provide information concerning the
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distribution of the sensitivity to chemicals in people. Zoetetnan and
Pietl utilized the results of their judges and probability calcula-
tions to determine the percentage of observers still able to detect
the odor at subthreshold levels. Working with taste thresholds,
Powers et zil.10 used extreme value calculation to predict the range
within which the threshold of the population might occur. This
was accomplished by using a panel of only seven people. The taste
thresholds of 63 additional judges were within the predicted range.
The statistical theory of extreme values has been used in many di-
verse fields such as meteorological extremes, floods, breaking
strength of textiles, span of human life, gust loads experienced by
an airplane in flight, and breakdown voltage of capacitors-'-^. The
work of Powers et a!L.^0 demonstrated that extreme value statistics
could be used on threshold data and give useful information on the
distribution of the sensitivity to taste or odor of chemicals in
people.
OBJECTIVE
The objectives of this investigation were to determine the odor
threshold in water of organic compounds that were identified in
industrial effluents and to predict the percentage of the population
that might have odor thresholds lower than that of the panel by
using extreme value calculations.
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SECTION III
MATERIALS AND METHODS
The compounds used for odor thresholds determinations were supplied
by the Southeast Environmental Research Laboratory, United States
Environmental Protection Agency. The purity of most of the chemicals
were' determined by gas liquid chromatography and with the exception
of 1-methyl naphthalene were at least 98% pure. These compounds
were found frequently as pollutants in industrial effluents^.
The odor thresholds In water were determined using a procedure derived
from a modification of a sensory test that was used for taste thres-
holds in earlier worfclO. Stock solutions of the chemicals were made
by dissolving the chemicals in odor free water. Geometric dilutions
were made and the sample was evaluated by judges. When the compound
was not soluble in water, it was dissolved in 50 ml of propylene
glycol. The appropriate dilutions in water were made from this
propylene glycol solution solution. The same amount of proplyene
glycol that was in the sample dilutions was also dissolved in the
water blank to prevent the judges from making their decision by
looking at the difference in surface tension of the solutions. The
appropriate dilution of the chemical was added to the odor flask,
500 ml glass stoppered (ST32) Erlenmeyer flask, containing enough
odor-free water to make the total volume of 200 ml.
THRESHOLD DETERMINATION
Using the triangle procedure the odor thresholds were determined
against odor-free water. In each set of three flasks, two contained
odor-free water and one the test substance or two test substances and
one odor-free water. The judges were asked to determine the different
sample in each set of three samples. The evaluations were conducted
on ten three-sample sets at each concentration of the test substance.
In order for the judge to significantly detect the odor at the 95%
confidence level, seven correct responses were required at any con-
centration. A geometric increase or decrease in concentration was
made and the evaluation repeated until the threshold was determined
for each judge. Seven to fourteen judges were used to determine the
odor threshold of the compounds.
The odor threshold determinations were conducted in a room designed
for sensory evaluations. Five three-sample sets were placed in the
room and were evaluated by the judges. The judges were instructed
to shake the flask, remove the stopper and sniff the vapors and
record their response. Each judge evaluated samples twice a day, once
at mid-morning and mid-afternoon.
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The odor thresholds were determined at room temperature and 60 C.
For the 60°C evaluation, the odor flask were placed in a 60 + 1°C
water bath prior to and during the evaluation.
The geometric mean of all judges' thresholds was calculated to
indicate the threshold for each substance tested. The individual
judge's threshold was used to make extreme value calculations in
order to predict the lowest threshold that a given percentage of the
population might have . Liebleim's-'--'- method of extreme value calcu-
lation was followed. An example of the calculation is given in
Liebleim* s^-l report. A computer program was developed and all calcu-
lations in this report were done at the University of Georgia Computer
Center.
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SECTION IV
RESULTS AND DISCUSSION
THRESHOLD VALUE DETERMINATIONS
The judges for the odor threshold determinations were selected from
graduate students, faculty and technicians in the Food Science De-
partment. At the start of the study, the judges were asked to
evaluate 10 3-sample sets. However, it was soon observed that 10
sets were too many samples for the judges to evaluate at one time
because their olfactory system became fatigued. It was found that
the judges could easily evaluate 5 3-sample sets without over-working
their olfactory system.
The initial concentration of a compound to be evaluated was one that
all of the judges was expected to detect. This familiarized the
judges with the odor of the compound and also assured that only de-
creasing dilutions were needed in future evaluations on that compound.
In some instances, however, some judges could not detect the initial
concentration and samples with a higher concentration had to be made
for them.
If a judge made seven or more correct decisions out of ten evaluations,
he was asked to evaluate the samples at the next lower dilution. A
judge stopped evaluating samples when he gave fewer than seven correct
responses. Table 1 illustrates the type of data obtained for the
threshold determination of acenaphthene. If a judge obtained more
than 7 correct answers at one concentration and less than 7 on the
next dilution, the log of percent positive answers was plotted against
concentration and his threshold was obtained from the 70% positive
point on the graph.
Tables 2 and 3 list the threshold values in water of the 13 compounds
used in this study. The odor threshold of n-butanol was determined
in order to compare values obtained with our procedure to values
determined by other workers. Reported odor threshold of n-butanol
in water range from 1 to 2.5 ppnH-2,13. our odor threshold values for
n-butanol were 2.77 at room temperature and 2.88 at 60°C. These
values compare very favorably with reported data. The range of odor
threshold for n-butanol as obtained by our group of judges was also
very narrow (1.66 - 5.00 ppm at room temperature and 2.14 - 4.04 ppm
at 60°C). This would tend to indicate that the variation in sensiti-
vity to n-butanol among people is not too great.
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Table 1. JUDGES RESPONSE FOR THE ODOR THRESHOLD OF ACENAPHTHENE AT ROOM TEMPERATURE
Judge
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Concentration (ppm)
0.500
io/ioa
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
0.250
10/10
10/10
10/10
9/10
7/10
9/10
10/10
TO/ 10
10/10
10/10
9/10
9/10
10/10
8/10
0.125
10/10
8/10
6/10
8/10
10/10
10/10
10/10
8/10
9/10
8/10
9/10
5/10
9/10
4/10
0.063
9/10
6/10
3/10
5/10
7/10
9/10
7/10
9/10
5/10
4/10
4/10
0.031 0.015
7/10 3/10
4/10
9/10 6/10
9/10 4/10
4/10
Threshold
(ppm)
0.031
0.097
0.162
0.114
0.092
0.063
0.021
0.025
0.053
0.108
0.105
0.196
0.103
0.226
Correct responses/number evaluated
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Table 2. ODOR THRESHOLD CONCENTRATIONS IN WATER OF CHEMICALS AT ROOM TEMPERATURE (ppm)
oo
Compound
Acenaphthene
2-Ethy 1- 1-Hexanol
Butanol
Geosmin
2-Methyl Naphthalene
1-Methyl Naphthalenea
Diacetone -Alcohol
Dibenzofuran
2-Benzothiazole
2-Mercaptobenzothiazole
2-Ethy 1-4-Methy 1-1 , 3-Dioxolane
Caprolactam
d-Camphor
Number of
Judges
14
13
8
9
10
10
9
10
8
7
8
8
8
Room Temperature
Threshold
0.08
1.28
2.77
0.13 x 10~3
0.01
0.02
44.12
0.12
0.08
1.76
0.38
59.7
1.29
Range
0.02 -
0.58 -
1.66 -
(0.03 - 0.
0.003 -
2.52 x 10
5.63 -
0.04 -
0.01 -
0.40 -
0.14 -
36.0 -
0.25 -
0.22
2.08
5.00
50) x 10~3
0.04
"3 - 0.17
269
0.51
0.98
10.9
1.39
100.0
3.83
Contains 28% 2-Methyl Naphthalene
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Table 3. ODOR THRESHOLD. CONCENTRATIONS IN WATER OF CHEMICALS AT 60 C (ppm)
Compound
Acenaphthene
2-Ethyl-l-Hexanol
Butanol
Geosmin
2-Methyl Naphthalene
1-Methyl Naphthalene3 "
Diacetone Alcohol
Dibenzofuran
2-Benzothiazole
2-Mercaptobenzothiazole
2-Ethyl-4-Methyl-l, 3-Dioxolane
Capro lac tarn
d-Camphor
Number of
Judges
14
13
8
9
10
10
9
10
8
7
8
8
8
Threshold
0.08
0.78
2.88
.18 x 10~3
0.02
0.05
54.9
0.25
0.45
1.20
0.36
208.7
0.28
60°C
Range
0.0019
0.58 -
2.14 -
(0.0078 -
0.003
0.97 x
7.90 -
0.05 -
0.024
0.28 -
0.07 -
10.7 -
0.18 -
- 0.33
1.24
4.04
1.54) x 10~3
- 0.17
10~3 - 0.4
90.0
0.51
- 0.96
2.80
0.81
1482.0
0.44
Contains 28% 2-Methyl Naphthalene
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Gas chromatography analysis of 1-methyl napthalene revealed that it
contained 28% 2-methyl naphthalene. Therefore, the 1-methyl
naphthalene odor threshold values listed in Tables 2 and 3 are for
this mixture. Since the odor thresholds for these two compounds are
similar and if there is no additive or synergistic effect between the
odors of 1-methyl naphthalene and 2-methyl napthalene, the threshold
values for pure 1-methyl naphthlene would not change significantly
from the values reported in Tables. 2 and 3.
The threshold values for all the compounds at 60 C were close to or
higher than the threshold values at room temperature. Since more
molecules would be in the vapor phase at 60°C than at room tempera-
ture, one would expect the threshold value to be lower at the higher
temperature. Perhaps the threshold values at 60°C were influenced
by the increased water vapor which saturated the olfactory system
and made the judges less sensitive to the compounds. This increased
water vapor did not affect all judges in the same way. Some judges
were more sensitive at 60°C than at room temperature while for other
judges the reverse was the case. This phenomenon also varied from
compound to compound. In one instance a judge may be the most sensi-
tive to one compound and the least sensitive to the next.
As indicated in Tables 2 and 3 the range of threshold values for the
limited number of judges used in this study is large. Many of the
threshold values differed by a factor of 100 and for 1-methyl naphtha-
lene at 60°C the difference between the highest and lowest threshold
values was over 1,000. Because of this wide range in threshold
values, the geometric average threshold value for a compound is not
too helpful in providing information to the people in charge of con-
trolling the odor of the water supply. Information concerning the
concentration of a compound that a given percentage of the people
cannot detect would be more useful to them. Extreme value calcula-
tion is one method that can provide this information.
EXTREME VALUE CALCULATIONS
Each judge's threshold value was used in the extreme value calculations.
Figures 1 and 2 illustrate extreme value plots for the threshold
values for two of the compounds. In these figures the center line
(-Q-Q-) is the regression line as calculated from the experimentally
determined threshold values. The upper line (-O—O—) and the lower
line (-A—^3f) are the upper and lower 0.95 confidence limits. The
points on the graphs, were taken from the computer calculations and
were used only to draw the line on the figure.
Using the lower .95 confidence level for geosomin (Figure 1), 90% of
the population would have a threshold of 4.4 x 10~6 ppm (log = -5.39)
or higher. The other 10% of the population would be able to detect
10
-------
E
a
a
v
z
O
x
ff
ac
-3 —
•= -5
-6
-7
-8
-9
-10
-11
J L
30 50
90
95
99
993
PERCENTAGE OF POPULATION THAT CAN DETECT ODOR AT ANY CONCENTRATION
FIGURE 1. EXTREME VALUE PLOT FOR ODOR THRESHOLD LEVELS FOR GEOSMIN
-------
E
a
a
-x
i
>-
at
^
Z
in
u
u
s
O
1
0
-1
-2
-3
£ -4
O
O
I I
I 1
30 50
90
95
99
99.9
PERCENTAGE OF POPULATION THAT CAN DETECT ODOR AT ANY CONCENTRATION
FIGURE 2. EXTREME VALUE PLOT FOR ODOR THRESHOLD LEVELS FOR 2-ETHYL-4-METHYL-1)3-DIOXOLANE
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Table 4. CONCENTRATIONS OF CHEMICALS THAT MAY BE DETECTED BY VARIOUS SEGMENTS OF THE POPULATION
AS PREDICTED BY EXTREME VALUE CALCULATIONS (ppm)
Compound
Acenapthene
2-Ethy 1- 1-Hexanol
Butanol
Geosmin
2-Methyl Naphthalene
1-Methyl Naphthalene9 -
Diacetone Alcohol
Dibenzofuran
2-Benzothiazole
2-Mercaptobenzothiazole
2-Ethy 1-4-Me thy 1- 1 , 3-
Dioxolane
Caprolactam
d- Camphor
Threshold
Value
8.
1.
3.
1.
1.
2.
44
1.
8.
1.
3.
59
,1.
0 x 10~2
3
8
3 x 10"4
_2
3 x 10~
3 x 10"2
.1
2 x 10~
8 x 10~2
8 x 10"1
8 x 10"1
.6
3
Percent of Population Still
2.6
6.1
1.5
1.3
2.0
2.1
4.6
1.9
1.8
7.9
8.8
25
1.3
20
x 10~2
x 10"1
x 10~5
_•*
x 10
x 10"3
x 10~2
x 10~"3
x 10~2
x 10"2
1
x 10
10
1.4 x
4.2 x
1.2
4.1 x
7.9 x
7.5 x
1.4
6.1 x
2.6 x
1,6 x
3.9 x
16
4.1 x
Able to
1
io-2
lO'1
io-6
-4
10 4
io~4
io-3
io-4
io-2
io-2
_2
10 *
1.9
1.2
4.4
9.7
3.9
1.8
3.2
1.7
4.1
8.8
2.9
3.8
9.2
x 10~3
x 10"1
x 10"1
x 10"8
_5
x 10
x 10"5
x 10"2
x 10"4
x 10"7
x 10"5
x 10"3
-2
x 10
Detect
Odor
0.1
2.1
3.5
1.6
2.3
1.9
4.5
7.6
4.9
6.8
5.1
2.2
9.2
2.1
x
x
X
X
X
X
X
X
X
X
X
X
X
io-4
io-2
io-1
io-9
-6
10
io-7
io-4
io-6
io-10
io-7
io-4
io-1
-5
10
Contains 28% 2-Methyl Naphthalene
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geosmln at concentration lower than 4.4 x 10 ppm. The Tnlnimal
concentration that any desired percentage of the population could
detect can be obtained from the extreme value regression plot of
the experimentally determined threshold values (lower confidence
line in Figure 1).
Table 4 lists the odor threshold values determined at room temperature
for the 13 compounds. Also included in Table 4 are the concentrations
which a given percentage of the people are still able to detect. The
minimal detectable concentration does not differ from the threshold
value by the same magnitude for all of the compounds. If we consider
the concentrations that one percent of the observers can still detect,
we find that the detectable concentrations for butanol, acenaphthene
and caprolactan differ from the threshold concentrations by a factor
of approximately 10 while the magnitude of the difference for
2-mercaptobenzothiazole, d-camphor and geosmin is approximately 10,000.
Also, one tenth of the observers can still detect 2-benzothiozole at
a level which is 1/100,000th of the threshold concentration.
It appears that the distribution of the sensitivity to odors in man
differs from compound to compound and it is impossible to predict
the concentration of a compound that a given population can detect
from the information obtained from another compound. Each compound
that is found to be an odor pollutant should be evaluated by a small
group of judges and the odor threshold determined. Calculations such
as extreme value analysis could be done to predict the concentration
that a given percentage of people could still detect. This would
provide a guideline which could be used by those in charge of removing
the pollutant from the water if complete removal of the pollutant is
impossible.
ODOR THRESHOLD CONCENTRATIONS REPORTED BY OTHER WORKERS
2
The odor threshold in water of 56 of the compounds listed by Webb
were reported by other workers. These odor thresholds are listed
in Table 5. Many of these were reported in the reviews made by
•i 2 -I o
Zoeteman and Stahl-1- . Some of these compounds have several reported
thresholds with large differences among them. This difference in
threshold concentrations may be due to the procedures used for the
odor threshold determinations and sensitivities of the judges used to
detect the odor. Although the odor threshold concentration is known
for these compounds, information concerning the distribution of the
observers sensitivities to these compounds would be of greater value
to the workers in charge of removing pollutants from the water supply.
14
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Table 5. ODOR THRESHOLD CONCENTRATIONS OF CHEMICALS IN WATER
Compound
Acetophenone
Acrylonitrite
Aldrin
Arachidic acid
Benzaldehyde
1-Butanol
t-Butylisothiocyante
Chlordane
o-Cresol
m-Cresol
p-Cresol
Cumene
Cyclohexanol
Threshold
(ppm)
6.8 x 101
1.7 x 10-1
6.5 x 10-2
3.9 x 10~3 - 2.02
3.9 x 10~3
2.02
1.86
2.9 x 10
19
1.70 x 10~2
2.0 x 10~ 3
2.0 x 101
1.8 x 10~4
4.29 x 10~ 3
4.0 x 10~ 3
4.4 x 10~4
3.0 x 10~3
4.36 x 10~4
3.0 x 10- 3
2.5
1.67 x 10~3
2.5 x 10~,
5.0 x 10
,9.0 x 10~2
6.5 x 10"1
2.6 x lO"1
6.8 x Id"?"
2.5 x 10"1
5.5 x 10"2
1.0 x 10"1
3.5
Source
13
12
12
7
13
13
13
12
15
13
12
13
13
13
13
13
13
13
13
13
13
12
13
13
9
13
9
9
12
12
15
-------
Table 5. (Continued) ODOR THRESHOLD CONCENTRATIONS OF CHEMICALS IN WATER
Compound
p-Cymene
n-Decane
2 , 6-Dinitrotoluene
Diphenylether
Dodecane
Endrin
2-Ethy 1- 1-hexano 1
Ethyl Phenylacetate
Fufural
Guaiacol
Heptachlor
Hexachlorobenzene
Hexachlorocyclopentadiene
Hexachlorobutadiene
1-Hexanol
Indene
Isopentyl Alcohol
Limonene
alpha-Methyl Benzyl Alcohol
o-Methy Is tyrene
Threshold
(ppm)
1.0 x 10"1
1.0 x 101
1.0 x 10"1
1.5 x 10~2
1.0 x 102
4.1 x 10~2
1.8 x 10~2
2.7 x 10"1
6.5 x 10"1
6.0 x lO'1
1.0 x 10°
2.1 x 10~2
1.3 x 10~2
2.0 x 10~2
3.0 x 10°
1.0 x 10"3
6.0 x 10~3
5 x 10"1
1.0 x 10~3
4.0 x 10°
1 x 10~3
1.5 x 103
1.0 x 10"1
16
; Source
12
12
12
12
12
13
13
12
12
13
12
13
12
13
12
12
13
13
12
12
12
13
12
12
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Table 5. (Continued) ODOR THRESHOLD CONCENTRATIONS OF CHEMICALS IN WATER
Compound
Myristic Acid
Naphthalene
Nitrobenzene
o-Nitropheno 1
1-Octanol
Palmitic Acid
Pentachlorophenol
Pentadecanoic Acid
Phenathrene
Phenol
beta-Pinene
Quinoline
Stearic acid
Styrene
alpha- Terpineol
Terpinolene
1,1,2,2, -Tetrachloroethane
Threshold
(ppm)
10 x 10~3
6.8 x 10~2
2.0 x 10'1
3 x 10-2
1.0 x 101
1.3 x 10'1
1 x 101
3.0 x 10'1
1.0 x 101
1.0 x 10°
5.9
7.5
1.0 x 10°
4.2
1.4 x 10"1
7.1 x 101
1.6 x 10~2 - 4.3
2.1 x 101
1 7.3 x 10'1
3.7 x 101
3.4 x 10~
3.5 x lO'1
2.x ID'1
5 x ID'1
Source
13
13
12
14
12
13
13
12
12
12
13
13
12
9
13
13
7
13
13
13
13
13
13
13
17
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Table 5. (Continued) ODOR THRESHOLD CONCENTRATIONS OF CHEMICALS IN WATER
Compound Threshold Source
(ppm)
iso-Valeric 5.0 x 10° 12
n-Valeric 1.0 x 101 12
n-Undecane 1.0 x 10 12
Vanillin 2 x lo"1 13
4.0 13
2.2 x 10° 12
x-Xylene 2.2 12
1.8 9
m-Xylene 5.0 x 10~2 12
1.0 9
p-Xylene 1.0 - 12
5.3 x 10 9
18
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SECTION V
REFERENCES
1. Zoeteman, B. C. T. and G. J. Piet. Cause and Identification of
Taste and Odor Compounds in Water. Presented at Symposium on
"Identification and Transformation of Aquatic Pollutants", April
8-10, Athens, Georgia, 1974.
2. Webb, R. G., A. W. Garrison, L. H. Keith, and J. M. McGuire.
Current Practice in GC-MS Analysis of Organics in Water. South-
eastern Environmental Research Lab. National Environmental
Research Center, Office of Research and Monitoring, US EPA,
Corvallis, Oregon. EPA Report No. EPA-R2-73-277, 1973.
3. Amerine, M. A., R. M. Pangborn, and E. B. Roessler. Principles
of Sensory Evaluation of Food. New York, Academic Press, Inc., pp.
145-219, 1965.
4. Haring, H. G., F. Rykens, H. Boelens, and A. Vander Gen. Olfacto-
ry Studies on Enantiomeric Eremophilane Sesquiterpenoids. J. Agr.
Food Chem. 20:1018-1021, 1972.
5. Guadagni, 0. G., R. G. Buttery, and S. Okano. Odour Thresholds
of Some Organic Compounds Associated with Food Flavours. J. Sci.
Food Agric. 14:761-765, 1963.
6. Buttery, R. G., D. G. Guadagni, and L. C. Ling. Flavor Compounds:
Volatiles in Vegetable Oil and Oil-Water Mixtures. Estimation of
Odor Thresholds. J. Agri. Food Chem. .21:198-201, 1973.
7. Baker, R. A. Threshold Odors of Organic Chemicals. J. AWWA 9_:
913-916, 1962.
8. Baker, R. A. Critical Evaluation of Olfactory Measurement.
J.W.P.C.F. _34:582-591, 1962.
i
9. Rosen, A. A., J. B. Peter and F. M. Middleton. Odor Thresholds
of Mixed Organic Chemicals. J.W.P.C.F. _34:7-14, 1962.
10. Powers, J. J., A. J. Howell, D. A. Lillard, and S. J. Vacinek.
Effect of Temperature on Threshold Values for Citric Acid, Malic
Acid and Quinine Sulphate - Energy of Activation and Extreme -
Value Determinations. J. Sci. Fd. Agric. 22.:543-547, 1971.
11. Liebleim, J. Technical Notes Natn. Advis. Comm. Aeronaut.,
Washington, Technical Note 3053, 88 pp., 1954.
19
-------
12. Zoeteman, B. C. J., G. J. Piet, C. T. M. Ruygrok and R. Van de
Heuvel. Threshold Odour Concentrations in Water of Chemical
Substance. Annex to Bulletin No. 73-7, National Institute for
Water Supply. The Hague, The Netherlands, 1974.
13. Stahl, W. H., editor. Compilation of Odor and Taste Thresholds
Value Data. Data Series No. 48, Am. Society for Testing and
Materials, Philadelphia, Pa. 19103, 1973.
14. Klein, L. Aspects of River Pollution. New York, Academic Press,
Inc., 1957.
15. Leithe, W. The Analysis of Organic Pollutants in Water and Waste
Water. Ann Arbor, Ann Arbor Science Publishers, Inc., 1973.
20
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO.
EPA-660/4-75-002
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
Aqueous Odor Thresholds of Organic Pollutants
in Industrial Effluents
Jan..1975. preparation da:e
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
D. A. Lillard and J. J. Powers
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Food Science
University of Georgia
Athens, GA 30602
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
R-802980-01
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
National Environmental Research Center
Corvallis, Oregon 97330
13. TYPE OF REPORT AND PERIOD COVERED
Final Grant Report
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This investigation was designed to determine the odor thresholds in
water of organic pollutants that have been identified in industrial
effluents. Seven to fourteen judges were used to determine the odor
threshold values of 13 compounds at room temperature and 60°C. Odor
threshold values for the compounds in ppm at room temperature are:
acenaphthenee 0.08; 2-ethyl-l-hexanol, 1.28; butanol, 2.77; geosmin,
0.13 x 10 ; 2-methyl naphthalene, 0.01; 1-methyl naphthalene, 0.02;
diacetone alcohol, 44.1; dibenzofuran, 0.12; 2-benzothiazole, 0.08;
2-mercaptobenzothiazole, 1.76; 2-ethyl-4-methyl-l,3-dioxolane, 0.38;
caprolactam, 59.7; d-camphor, 1.29. Extreme value calculations were
made to predict a concentration below which a certain percentage of
the population might still be able to detect the compound(s). The
threshold values obtained at 60°C in most cases do not differ or are
higher than those determined at room temperature.
This report was submitted in fulfillment of Project Number R802980-01
by the University of Georgia under the partial sponsorship of the
Environmental Protection Agency. Work was completed as of September
15, 1974.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Gioup
Odor, Water Analysis, Organic
Wastes, Statistical Methods.
Odor thresholds,
extreme value
calculations, tri-
angle test.
05A
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (ThisReport)
21. NO. OF PAGES
Release Unlimited, Copies available>
from senior author.
26
20. SECURITY CLASS (Thispage)
22. PRICE
EPA Form 2220-1 (9-73)
0 U.S. GOVERNMENT PRINTING OFFICE: I97J-698-472 /I42 REGION 10
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