United States
Environmental Protection
Agency
Environmental Research
Laboratory
Athens GA 30605
EPA-600 3-80-041
April 1980
Research and Development
c/EPA
Sorption Properties of
Sediments and
Energy-Related
Pollutants
-------
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 ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/3-80-041
April 1980
SORPTION PROPERTIES OF SEDIMENTS AND
ENERGY-RELATED POLLUTANTS
by
a b
John J. Hassett and Jay C. Means
Co-Principal Investigators
Wayne L. Banwarta and Susanne G. Wood
Department of Agronomy, University of Illinois at Urbana-
Champaign, Urbana, Illinois 61801
Chesapeake Biological Laboratory, University of Maryland
Solomons, Maryland 20688
clnstitute for Environmental Studies, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801
Contract No. 68-03-2555
Project Officer
David S. Brown
Environmental Processes Branch
Environmental Research Laboratory
Athens, Georgia 30605
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ATHENS, GEORGIA 30605
-------
DISCLAIMER
This report has been reviewed by the Environmental Research Laboratory,
U.S. Environmental Protection Agency, Athens, Georgia, and approved for pub-
lication. 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 endorsement or recom-
mendation for use.
ii
-------
FOREWORD
Environmental protection efforts are increasingly directed towards
prevention of adverse health and ecological effects associated with specific
compounds of natural or human origin. As part of this Laboratory's research
on the occurrence, movement, transformation, impact, and control of environ-
mental contaminants, the Environmental Processes Branch studies the micro-
biological, chemical, and physico-chemical processes that control the trans-
port, transformation, and impact of pollutants in soil and water.
Efforts to achieve our national goal of energy independence will require
increasing use of our country's vast domestic coal reserves. The combustion
of coal or its conversion to a gaseous or liquid fuel, however, can release
numerous organic compounds that are potentially toxic, carcinogenic, or muta-
genic. This report examines the sorption properties of several energy-rela-
ted pollutants on sediments. Information on these properties is needed to
predict the movement of the compounds in aquatic systems so that potential
environmental problems can be anticipated.
David W. Duttweiler
Director
Environmental Research Laboratory
Athens, Georgia
iii
-------
ABSTRACT
This report describes the factors that determine the extent of sorption
of organic compounds that are representative of coal conversion waste streams.
The compounds, all radiolabeled, were acetophenone, 1-naphthol, pyrene,
7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene, dibenz[a,h]anthracene,
acridine, 2,2'-biquinoline, 13#-dibenzo[a,i]carbazole, dibenzothiophene,
benzidine, 2-aminoanthracene, 6-aminochrysene, and anthracene-9-carboxylic
acid. Batch equilibrium isotherms were determined for each compound on four-
teen sediments and soils that had been collected from the Missouri, Illinois,
Mississippi and Ohio rivers and their watersheds. Laboratory procedures for
determining octanol-water partition coefficients and water solubilities were
developed and then performed on the compounds.
The sorption constants were correlated with soil and sediment proper-
ties and with the water solubilities and octanol-water partition coefficients
of the compounds. Regression equations were developed that allow prediction
of a hydrophobic compound's linear partition coefficient from knowledge of
the compound's octanol-water partition coefficient or its water solubility
and the organic carbon content of the sediment or soil. Regression equations
were tested on independent data sets from the literature for the adsorption
of parathion and a variety of halogenated hydrocarbons. Observed values for
these compounds were in good agreement with values predicted by the regression
equations.
This report was submitted in partial fulfillment of Contract No. 68-
03-2555 by the Department of Agronomy and the Institute for Environmental
Studies of the University of Illinois at Urbana-Champaign under the sponsor-
ship of the U.S. Environmental Protection Agency. The report covers the
period from July 1, 1977 to December 31, 1979-
-------
CONTENTS
Foreword , iii
Abstract iv
Figures vii
Maps ix
Tables x
Acknowledgments xiv
SECTION 1. INTRODUCTION 1
SECTION 2. CONCLUSIONS 4
SECTION 3. RECOMMENDATIONS 12
SECTION 4. LABORATORY INVESTIGATIONS 13
4.1. Acetophenone 13
4.2. 1-Naphthol 18
4.3. Benzldine 27
4.4. Pyrene 35
4.5. 7,12-Dimethylbenz[a]anthracene .... 41
4.6. Dibenz[a,h]anthracene 46
4.7. 3-Methylcholanthrene 51
4.8. Dibenzothiophene 56
4.9- Acridine 62
4.10. 2,2'-Biquinoline 67
4.11. 13S-Dibenzo[a3i]carbazole 71
4.12. 2-Aminoanthracene 76
4.13. 6-Aminochrysene ..... 80
4.14. Anthracene-9-Carboxylic Acid 84
SECTION 5. EXPERIMENTAL METHODS 89
5.1. Preparation and Tritiation of Compounds 89
5.1.1. Chromatographic Analyses , 89
5.1.1.1. Thin-Layer Chromatography 89
5.1.1.2. Gas-Liquid Chromatography 91
5.1.2. Purity and Purification Procedures 91
5.1.2.1. Determination of Specific Activity
and Radiochemical Purity 91
5.1.2.2. Purification of Compounds , 93
5.1.3. Tritiation 95
5.1.4. Radioactivity Measurements . . i 96
5.2. Octanol-Water Partitioning Procedure .... 97
5.3. Water Solubility Determination 99
5.4. Degradation Studies 102
5.4.1. Sorption Isotherms 102
-------
CONTENTS Continued
5.4.1.1. Soil/Sediment Phases , , , . . 102
5.4.1.2. Aqueous Phases , 104
5.4.2. Octanol-Water Partitionings 104
5.4.2.1. Octanol Phases 104
5.4.2.2. Aqueous Phases 105
5.4.3. Water Solubilities 105
SECTION 6. SAMPLE SELECTION AND CHARACTERIZATION 106
6.1. Criteria for Sample Selection 106
6.2. Sample Characterization ..... 110
6.2.1. Instrumentation Neutron Activation
Analysis (INAA) Ill
6.2.2. Clay Mineral Analysis Ill
6.2.3. Amorphous Al, Fe and Si 116
6.3. Effect of Sample Pretreatment on
Sorption of Acetophenone by Sediments 119
6.3.1. Experimental Methods 119
6.3.2. Results and Discussion 121
6.3.2.1. Sample Pretreatment 121
6.3.2.2. Effect of Extent of Grinding 123
6.3.2.3. Organic Matter Removal 124
SECTION 7. LITERATURE CITED 127
vi
-------
FIGURES
Number Page
2.1 Relationship between Koc and Octanol-Water Partition
Coefficient (Kow) of Energy-Related Organic Pollutants .... 7
2.2 Relationship between Koc and Water Solubility (S) of
Energy-Related Organic Pollutants ..... 9
4.1 Representative Isotherms for the Sorption of Acetophenone
by Soils and Sediments 15
4.2 Representative Isotherms for the Sorption of 1-Naphthol
by Soils and Sediments 22
4.3 Relationship between Molar Kd (for the Sorption of
1-Naphthol) and %OC for Ten Soil and Sediment Samples
Showing High Correlation between the Two Parameters
and for Six Samples that Gave High Koc Values 23
4.4 Relationship between Koc (for the Sorption of 1-Naphthol)
and the %OC/Montmorillonite Ratio of Soils and Sediments
for Ten Samples Showing High Correlation between Kd and
%OC and for Six Samples that Gave High Koc Values 24
4.5 Effect of Varying the EthanolrWater Ratio in the Solvent
System on Soil TLC Rf Values for Dicamba, cx-Naphthol and
3-Methylcholanthrene 26
4.6 Representative Isotherms for the Sorption of Benzidine
by Soils and Sediments 29
4.7 Effect of pH on the Sorption of Benzidine by Soils
and Sediments 33
4.8 Representative Isotherms for the Sorption of Pyrene
by Soils and Sediments 37
4.9 Representative Isotherms for the Sorption of 7,12-Dimethyl-
benz[a]anthracene by Soils and Sediments 43
4.10 Representative Isotherms for the Sorption of Dibenz[o,?z]-
anthracene by Soils and Sediments 48
vii
-------
FIGURES Continued
Number Page
4.11 Representative Isotherms for the Sorption of 3-Methyl-
cholanthrene by Soils and Sediments 52
4.12 Representative Isotherms for the Sorption of Dibenzo-
thiophene by Soils and Sediments , 58
4.13 Representative Isotherms for the Sorption of Acridine
by Soils and Sediments 65
4.14 Representative Isotherms for the Sorption of
2,2'-Biquinoline by Soils and Sediments ... 68
4.15 Representative Isotherms for the Sorption of
13#-Dibenzo[<2j-£]carbazole by Soils and Sediments 72
4.16 Representative Isotherms for the Sorption of 2-Atnino-
anthracene by Soils and Sediments 77
4.17 Representative Isotherms for the Sorption of 6-Amino-
chrysene by Soils and Sediments , . . 81
4.18 Representative Isotherms for the Sorption of
Anthracene-9-Carboxylic Acid by Soils and Sediments 85
5.1 Protocol for Determining the Octanol-Water Partition
Coefficient of a Hydrophobic Organic Compound 98
5.2 Protocol for Determining the Water Solubility of a
Hydrophobic Organic Compound 101
6.1 Comparison of Isotherms for the Sorption of Aceto-
phenone by Fresh and Air-Dried Samples of Crane
Island Sediment 122
6.2 Comparison of the Linear Partition Coefficients (Kp)
for the Sorption of Acetophenone by Soil and Sediment
Samples and the Percent Clay in the Samples after
Organic Matter Oxidation 126
viii
-------
MAPS
Number Page
6.1 Areas of High Potential for Coal Gasification
Development 108
6.2 Sampling Sites on the Missouri, Ohio, Wabash, Illinois
and Mississippi River Systems and their Watersheds 109
ix
-------
TABLES
Number Page
1.1 Compounds Selected for Study 3
2.1 Koc Values and their Correlation Coefficients for the
Sorption of Energy-Related Organic Pollutants by Soils
and Sediments; Octanol-Water Partition Coefficients
and Water Solubilities of the Same Compounds 6
2.2 Predicted and Measured Kd Values for the Sorption
of Parathion 10
2.3 Predicted and Measured Koc Values for the Sorption
of Halogenated Hydrocarbons by Willamette Silt Loam
(1.6% Organic Matter, 0.84% Organic Carbon) 10
4.1 Physical Properties of Acetophenone 13
4.2 Acetophenone Sorption Isotherm Data 16
4.3 Linear Partition Coefficients (Kp) and Koc Values for the
Sorption of Acetophenone by Soils and Sediments 17
4.4 Physical Properties of 1-Naphthol 18
4.5 1-Naphthol Sorption Isotherm Data 20
4.6 Freundlich Sorption Constants, r2 Values and Koc Values
for the Sorption of 1-Naphthol by Soils and Sediments 21
4.7 Physical Properties of Benzidine 27
4.8 Freundlich Constants (Kd and 1/n) and r2 Values for the
Sorption of Benzidine by Soils and Sediments (Molar Basis) ... 30
4.9 Benzidine Sorption Isotherm Data . 31
4.10 Modified Freundlich Partition Constants (1/n = 0.5) for the
Sorption of Benzidine (Kd£) and Ionized Benzidine (Kd3)
by Soils and Sediments (Molar Basis) 32
4.11 Physical Properties of Pyrene 35
-------
TABLES Continued
Number Page
4.12 Pyrene Sorption Isotherm Data 38
4.13 Freundlich Sorption Constants and Correlation Coefficients
(Kd, 1/n and r2) and the Modified Freundlich Partition
Constants (Kp, 1/n = 1) for the Sorption of Pyrene by
Soils and Sediments 39
4.14 Linear Partition Coefficients (Kp) and Koc Values for
the Sorption of Pyrene by Soils and Sediments 40
4.15 Physical Properties of 7,12-Dimethylbenz[a]anthracene .... 41
4.16 7,12-Dimethylbenz[a]anthracene Sorption Isotherm Data .... 44
4.17 Linear Partition Coefficients (Kp) and Koc Values for the
Sorption of 7,12-Dimethylbenz[a]anthracene by Soils
and Sediments 45
4.18 Physical Properties of Dibenz [a,7z]anthracene 46
4.19 Dibenz[a,h}anthracene Sorption Isotherm Data 49
4.20 Linear Partition Coefficients (Kp) and Koc Values for the
Sorption of Dibenz[a3h]anthracene by Soils and Sediments ... 50
4.21 Physical Properties of 3-Methylcholanthrene 51
4.22 3-Methylcholanthrene Sorption Isotherm Data 53
4.23 Linear Partition Coefficients (Kp) and Koc Values for the
Sorption of 3-Methylcholanthrene by Soils and Sediments ... 54
4.24 Physical Properties of Dibenzothiophene 56
4.25 Dibenzothiophene Sorption Isotherm Data 59
4.26 Linear Partition Constants (Kp) and Their r2 Values, and
Molar Freundlich Constants (Kd and 1/n) and Their r2
Values for the Sorption of Dibenzothiophene by Soils
and Sediments 60
4.27 Physical Properties of Acridine 62
4.28 Acridine Sorption Isotherm Data 64
4.29 Modified Freundlich Partition Constants (Kp, 1/n = 1) and
Koc Values for Sorption of Acridine by Soils and Sediments . . 66
xi
-------
TABLES Continued
Number Page
4.30 Physical Properties of 2,2'-Biquinoline 67
4.31 2,2'-Biquinoline Sorption Isotherm Data 69
4.32 Modified Freundlich Partition Constants (Kp, 1/n = 1) and
Koc Values for Sorption of 2,2'-Biquinoline by Soils and
Sediments 70
4.33 Physical Properties of 13#-Dibenzo[a.,i]carbazole 71
4.34 135-Dibenzo[o,£]carbazole Sorption Isotherm Data 73
4.35 Modified Freundlich Partition Constants (Kp, 1/n = 1) and Koc
Values for Sorption of 135-Dibenzo[o,£]carbazole by Soils and
Sediments 74
4.36 Correlation (r2) of 13#-Dibenzo[o,i]carbazole Kp with
Selected Soil/Sediment Properties for the 14 Soils and
Sediments Studied 75
4.37 Physical Properties of 2-Aminoanthracene 76
4.38 2-Aminoanthracene Sorption Isotherm Data 78
4.39 Linear Partition Coefficients (Kp) and Koc Values for
the Sorption of 2-Aminoanthracene by Soils and Sediments . . 79
4.40 Physical Properties of 6-Aminochrysene .... 80
4.41 6-Aminochrysene Sorption Isotherm Data 82
4.42 Linear Partition Coefficients (Kp) and Koc Values for the
Sorption of 6-Aminochrysene by Soils and Sediments 83
4.43 Physical Properties of Anthracene-9-Carboxylic Acid 84
4.44 Anthracene-9-Carboxylic Acid Sorption Isotherm Data .... 86
4.45 Linear Partition Coefficients (Kp) and Koc Values for the
Sorption of Anthracene-9-Carboxylic Acid by Soils and
Sediments 87
5.1 Typical Rf Values for 14 Energy-Related Compounds in
Selected Thin-Layer Chromatographic Solvent Systems 90
5.2 Typical Gas-Liquid Chromatographic Conditions and
Retention Times for 14 Energy-Related Compounds 92
xii
-------
TABLES Continued
Number Page
5.3 Radiochemical Purity Information for 14-Energy-Related
Compounds Used in this Study 94
5.4 Octanol-Water Partition Coefficients (Kow) of
Energy-Related Organic Pollutants 100
5.5 Water Solubilities of Energy-Related Organic Pollutants . . . 103
6.1 Field Notes 106-107
6.2 Characteristics of Soils and Sediments 110
6.3 Elemental Limits of Detection by Instrumental Neutron
Activation 112
6.4 Instrumental Neutron Activation Analysis of Soils
and Sediments 113-114
6.5 Qualitative Determination of the Different Clay Minerals
in the less-than-2y Fraction of the Soil and Sediment
Samples 115
6.6 Semiquantitative Determination of Clay Minerals in the
Soils and Sediments 117
6.7 Sodium Hydroxide-Extractable Si and Al and Citrate-
Dithionate-Extractable Fe in the Soil and Sediment Samples . . 118
6.8 Correlation Matrix of Selected Sample Characteristics .... 118
6.9 Selected Chemical and Physical Properties of River Sediments . 120
6.10 Effect of Sample Pretreatment on Modified Freundlich
Partition Coefficients (Kp) 121
6.11 Effect of Extent of Grinding on Sorption (Kp) of
Acetophenone 123
6.12 Organic Carbon Contents and Modified Freundlich Partition
Coefficients (Kp, 1/n = 1) Before and After Organic Matter
Removal, and Expandable (2:1) Clay Material in Soil and
Sediment Samples 124
xiii
-------
ACKNOWLEDGMENTS
The authors gratefully acknowledge the guidance and counsel of Dr.
David S. Brown, Project Officer, of the Environmental Research Laboratory,
Athens, Georgia. The authors also express their appreciation to Dr. Samuel W.
Karickhoff, Environmental Research Laboratory, Athens, Georgia, for valuable
advice regarding some technical difficulties encountered during the investi-
gation.
Special acknowledgment is made of the innovative technical contribu-
tions of Drs. Adam Khan and Syed Ali. The authors are grateful to John J.
Ameel, Sandra K. Dick, David D. Ellis, Carolyn T. Hanson, Elsa K. Tong, David
L. Zierath and Kathleen A. Brinkman for their excellent technical assistance,
and to V. Jean Clarke for typing this report.
xiv
-------
SECTION 1
INTRODUCTION
The contract contained two basic tasks. The first was to perform a
literature review covering the theory of sorption and the sorption properties
of energy-related compounds. This literature review, Adsorption of Energy-
Related Organic Pollutants (EPA-600/3-79-086), has been published by the U.S.
Environmental Protection Agency. The second task involved determination of
sediment/soil and pollutant properties that control sorption of compounds
typical of coal conversion effluent streams.
With the current proposed increase in the use of coal for energy
production, there is concern for the environmental effects of pollutants that
are produced at various stages of coal mining and processing. Coal is an
extremely complex organic polymer interlaced with inorganic trace impurities.
The following figure shows a typical chemical representation of the coal
polymer (1).
CH,
H
It is apparent that the var.ious fragments of the coal structure
include a tremendous variety of polycyclic aromatic, heterocyclic aromatic,
phenolic, amine, quinone, sulfurjnitrogen and other compounds. The charac-
terization of some of the organic wastes from coal conversion has been re-
ported for pilot plant studies. Forney et al. (2) identified spme of the
major organic constituents of tars produced by the Synthane coal gasification
process. Schmidt et al. (3) has analyzed process water for major organic
constituents.
-------
Coal conversion processes result in extremely large gaseous and aqueous
effluent streams (4). In addition to the wastes produced directly by the
conversion process, unspecified large quantities of water are produced
constituting the leachate from coal storage, solid wastes and particulates.
When effluent streams this large are produced, significant quantities of
constitutents can be placed into the environment.
Introduction of the effluent streams into the environment will result
in exposure of the organic pollutants to sediments or soils and their
subsequent sorption to the extent that it is chemically or physically
dictated. Sorption results in lower aqueous concentrations of the pollutants.
Hence, potential physiological activities (5) and release of mobilities
within the environment as well as other effects may be decreased. The extent
of sorption of organic materials by sediments and soils is dependent upon the
nature of both the sorbent (soil or sediment) and the sorbate (pollutant).
In a number of studies of organic pesticide sorption by soils, sorption
has been correlated with humus content, clay mineral type and content,
texture, pH and hydrous oxide content. The nature of the organic molecule,
whether it is a cation, anion or neutral molecule, its water solubility or
octanol-water partition coefficient, and its polarizability are a few of the
properties of the sorbate that interact with the solid phase to determine the
amount of sorption.
The sediments and soils used in this research were collected from the
Missouri, Mississippi, Illinois and Ohio rivers and their watersheds. These
samples provided a wide range in properties such as organic matter content,
clay content and type, and hydrogen ion activity (pH) that are known to affect
sorption. Sampling sites were in close proximity to potential coal gasifica-
tion areas (6).
The organic compounds selected for study (Table 1.1) are representative
of many of the classes of compounds found in coal conversion waste streams.
In addition, they encompass a wide range of compound properties that have
been shown to affect sorption.
-------
TABLE 1.1. COMPOUNDS SELECTED FOR STUDY
Polynuclear Aromatic Hydrocarbons
Pyrene
7,12-Dimethylbenz[a]anthracene
Dibenz\a3h]anthracene
3-Methylcholanthrene
Nitrogen and Sulfur Heterocyclics
Dibenzothiophene
Acridine
2,2'-Biquinoline
135-Dibenzo[a3£]carbazole
Aromatic Amines
Benzidine
2-Aminoanthracene
6-Aminochrysene
Aromatic Ketones
Acetophenone
Aromatic Alcohols
1-Naphthol
Organic Acids
Anthracene-9-carboxylic Acid
-------
SECTION 2
CONCLUSIONS
Sorption results when a solution component is concentrated at an inter-
face (7). For sediment-water or soil-water systems the interface of interest
has primarily been the solid-liquid interface. Sorption occurs when the
forces of attraction between the sorbing species and the solid surface
overcome both the forces of attraction between the sorbing species and the
solvent (8) and any repulsive forces between the sorbate and sorbent (9,10).
The sorbing species is called the solute when it is in solution and the
sorbate when it is sorbed to the sorbing surface (sorbent).
For organic compounds there are two general cases where the affinity
of the sorbate for the sorbent is greater than the affinity of the solute for
the solvent and significant sorption results. In the first case, there is a
strong specific interaction (coulombic attraction, ligand exchange or
hydrogen bonding (11)) between the sorbate and the sorbent, and these forces
of attraction overcome even a fairly strong attraction of the solute to the
solvent. The sorption of organic cations or polar organic molecules by
swelling clay minerals (12) is an example of this type of sorption. The
sorption of benzidine (Section 4.3) from acid solutions is an example from
this research (13).
Sorption that is characteristic of the second case results not because
of a large specific sorbate-sorbent interaction but rather because of a weak
solute-solvent interaction. In this case, even a weak positive sorbate-
sorbent interaction can overcome an extremely weak solute-solvent interaction
and result in the compound being removed from solution.
The weak solute-solvent interaction, that is, the low water solubility
or hydrophobic nature of many organic molecules, is the result of a large
decrease in entropy of the system upon solvation (14), coupled with an
absence of hydrophilic functional groups or at least a dominance of the
hydrophobic portion of the molecule. The attraction between a hydrophobic
organic molecule and the sorbent is not the result of specific interactions
as in the first case, but rather of general interactions between the sorbate
and sorbent such as van der Waals forces (14). The sorption of aromatic
hydrocarbons by soil or sediment humic materials is an example of this type
of sorption (15,16,17,18). This second case of sorption has been referred to
as hydrophobic sorption because of the emphasis on the role of the weak
solute-solvent (water) interaction (14,16).
Hydrophobic sorption increases as compounds become less and less polar,
that is, as molecular weights, molecular volumes or carbon numbers increase
-------
or as water solubilities decrease (15,18). Hydrophobic sorption has been
shown to be highly correlated with the organic carbon content of the soils or
sediments while at the same time relatively independent of other sorbent
properties (15,16,17,18). When sorption of hydrophobic compounds is expressed
as a function of the organic carbon content of the soil or sediment, a
constant, Koc, is generated which is a unique property of the compound being
sorbed (11,15,16,17,18):
Kd
Koc
%OC(decimal equivalent) (2-1)
where Koc is equal to the Freundlich constant (Kd) divided by percent organic
carbon (decimal equivalent) in the respective soil or sediment. Thus, for
these compounds, Kd values may vary dramatically from soil to soil or sediment
to sediment, but the Koc values converge toward a value that is constant
across all soils and sediments. For linear isotherms (1/n = 1) Kd may be
expressed on a mass basis or a molar basis; for nonlinear isotherms (1/n ^ 1)
Kd must be expressed on a molar basis (19). For linear isotherms the best fit
is often achieved by forcing 1/n to be equal to one. This has the effect of
expressing all the variation between isotherms in one constant (Kd). Small
changes in 1/n can result in large differences in Kd, masking any potential
correlation of Kd with sorbate or sorbent properties.
The partitioning of organic compounds between water and an organic
solvent, usually octanol, has been correlated with the extent of hydrophobic
sorption. Increasing octanol-water partition coefficients (Kow values) for a
series of compounds have been related to increased sorption when sorption is
expressed in terms of Koc values (15,18):
Kow = cone, cpd in octanol/conc. cpd in water (2-2)
where the octanol and water phases have been equilibrated to allow partition-
ing of the compounds between the two phases.
A summary of the results of the sorption experiments is given in Table
2.1. The Koc values were calculated from a regression (20) of the compounds'
linear or molar partition coefficients against the respective organic carbon
contents (decimal equivalents) of the 14 sediment and soil samples used in
the sorption experiments. The Koc values ranged from a low of 35 for
acetophenone to a high of 1,668,800 for d±benz[a3h]anthracene. The water
solubilities varied from 5,440 yg/ml for acetophenone to 0.00249 yg/ml for
dibenz[o,7z]anthracene. The octanol-water partition coefficients went from a
low of 38.6 for acetophenone to a high of 3,170,000 for dibenz[a,h]anthra-
cene. Individual Kp values and a more detailed discussion of the factors
affecting the sorption of the respective compounds are given in the following
sections.
Figure 2.1 presents the relationship of Koc and Kow for the compounds
studied as part of this contract with the exception of benzidine which is
protonated at low pH and then behaves as an organic cation (see Section 4.3),
The sorption data for the compounds studied by Karickhoff et at, (15) are
also included in order to expand this relationship to a greater number and
-------
TABLE 2.1. Koc VALUES AND THEIR CORRELATION COEFFICIENTS FOR THE SORPTION OF ENERGY-RELATED ORGANIC
POLLUTANTS BY SOILS AND SEDIMENTS; OCTANOL-WATER PARTITION COEFFICIENTS
AND WATER SOLUBILITIES OF THE SAME COMPOUNDS
Compound
Pyrene
7 , 12-Dimethylbenz [a] anthracene
Dibenz [a, h] anthracene
3-Methylcholanthrene
Dibenzothiophene
Acridine
2,2'-Biquinoline
135-Dibenzo [a., i ] carbazole
Acetophenone
1-Naphthol
Benzidine
2-Aminoanthracene
6-Aminochry s ene
Anthracene-9-carboxylic acid
Measured
Koc values
from isotherms
Koc r2
63,400
225,308
1,668,800
1,244,046
11,230
12,910
10,404
1,055,926
35
522
NAd
28,129
143,355
422
0.965
0.908
0.783
0.705
0.904
0.934
0.922
0.830
0.898
0.876
0.871
0.949
0.751
Octanol-water
partition
coefficient
Row ± S.D.
124,000 ± 11,000
953,000 ± 59,000
3,170,000 ± 883,000
2,632,000 ± 701,000
24,000 ± 2,200
4,200 ± 940
20,200 ± 2,200
2,514,000 ± 761,000
38.6 ± 1.2
700 ± 62
46.0 ± 2.2
13,400 ± 930
96,600 ± 4,200
1,300 ± 180
Water
Solubility0
S ± S..D.
(yg/ml)
0.135 ± 0.013
0.0244 ± 0.0042
0,00249 ± 0.00081
0.00323 ± 0.00017
1.47 ± 0.14
38.4 ± 4.5
1.02 ± 0.12
0.0104 ± 0.0041
5,440 ± 71
866 ± 31
360 ± 8.0
1.30 ± 0.159
0.155 ± 0.018
85.0 ± 1.9
aKoc values and correlation coefficients (r2) calculated from a regression of Kp against %OC (decimal
equivalent).
Determined by the procedure given in Section 5.2.
cDetermined by the procedure given in Section 5.3.
*%A = not applicable: non-hydrophobically sorbed compound; Koc values did not converge.
-------
7h
6
o
o
o
o
o
o
log Kow
FIGURE 2.1.
RELATIONSHIP BETWEEN Koc AND OCTANOL-WATER PARTITION COEFFICIENT (Kow) OF ENERGY-
RELATED ORGANIC POLLUTANTS
Data from Karickhoff et al. (15); o Data from this investigation.
-------
variety of compounds. A similar but inverse relationship between Koc and
water solubilities (S) was found for both sets, as illustrated in Figure 2.2.
The Koc values of the hydrophobic compounds were highly correlated with
their respective water solubilities or octanol-water partition coefficients.
log Koc = -0.686 log S(yg/ml) + 4.273 r2 = 0.933 (2-3)
log Koc = log Kow - 0.317 r2 = 0.980 (2-4)
The behavior of the aromatic hydrocarbons in both this and the
Karickhoff et at. (15) study is not unexpected. These compounds are highly
hydrophobic, lacking ring constituents or functional groups that could
significantly modify their hydrophobic nature. However, the fact that the
heterocyclic compounds studied as well as the compounds with reactive
functional groups, with the exception of benzidine, were also hydrophobically
sorbed strengthens the concept that the solute-solvent interaction is the
dominant interaction controlling the sorption of these compounds.
Equations 2-3 or 2-4 coupled with equation 2-1 represent a powerful
tool that can be used to predict the sorptive behavior of hydrophobic
compounds. Equation 2-3 or 2-4 can be used to predict the compound's Koc
value based on the water solubility or octanol-water partition coefficient.
The Koc value and the organic carbon content of the sorbent (soil or sediment)
can then be used with equation 2-1 to predict the linear partition coefficient
or molar Freundlich Kd value.
The use of equations 2-1, 2-3, and 2-4 can be illustrated by calcu-
lating the Koc value of parathion (0, (9-diethyl (3-p-nitrophenyl phosphoro-
thioate). Parathion (CioH^NOsPS) has a molecular weight of 291 and a
reported water solubility of 12.9 yg/ml (21).
log Koc = -0.686 log S + 4.273
log Koc = -0.686 log(12.9) + 4.273
log Koc = 3.511
Koc = 3244
In order to check the validity of the calculated Koc value, individual
Kd values were calculated for the samples used by Wahid and Sethunathan (21)
and predicted Kd values compared with their measured mass Kd values (Table
2.2).
Measured and predicted sorption constants were in good agreement and a
regression of the predicted Kd values for the sorption of parathion against
the measured values gave a correlation coefficient of 0.984. Regression of
the measured Mass Kd values against %OC (Table 2.2) gave a Koc value of 3329
which is in excellent agreement with the predicted Kd value of 3244.
-------
VO
7
6
5
-3
o
-2
-I
o
0
log
FIGURE 2.2. RELATIONSHIP BETWEEN Koc AND WATER SOLUBILITY (S) OF ENERGY-RELATED ORGANIC POLLUTANTS
• Data from Karickhoff et at. (15); o Data from this investigation.
-------
TABLE 2.2. PREDICTED AND MEASURED Kd VALUES FOR
THE SORPTION OF PARATHION
Sample
10
8
11
13
15
14
%OC
0.44
0.94
1.67
3.21
4.77
14.31
Mass
Kd
7.67
12.30
38.02
125.90
213.80
457.10
1/n
1.04
1.05
1.11
1.05
1.03
1.02
Predicted
Kd3
14.27
30.49
54.17
104.13
154.70
464.21
Kd = Koc x %OC (decimal equivalent).
TABLE 2.3. PREDICTED AND MEASURED Koc VALUES FOR THE SORPTION
OF HALOGENATED HYDROCARBONS BY WILLAMETTE SILT LOAM
(1.6% ORGANIC MATTER, 0.84% ORGANIC CARBON)
Compound
1, 2-Dichloroethane
1 , 2-Dichlor opropane
1, 2-Dibrotnoe thane
1,1,2, 2-Tetrachloroethane
1, 1, 1-Trichloreoethane
1, 2-Bromo-3-chlor opropane
1, 2-Dichlor obenzene
Tetrachlor ethane
Measured
Kda
0.30
0.43
0.58
0.74
1.66
1.20
2.88
3.36
Measured
KocB
36
51
69
88
198
143
343
400
Solubility
(yg/ml)
8,450
3,570
3,520
3,230
1,360
1,230
148
200
Predicted
Koc°
38
68
69
73
133
142
608
495
Kd = G x 0.016; Chiou et al. (22),
Koc = Kd v 0.0084
'log Koc = -0.686 log S + 4.273
10
-------
A second example of the utility and versatility of these equations is
given by comparing predicted Koc values with measured Koc values from a study
by Chiou et at. (22) on the sorption of a series of halogenated hydrocarbons
(Table 2.3).
Correlation of the predicted Koc values with the measured values
obtained by Chiou et dl. gave a correlation coefficient of 0.931. The study
of Chiou et al. illustrated the relationship of sorption and water solubility
for one soil. The present study illustrates that this relationship can be
extended to other classes of compounds and to other soils and sediments.
Equations 2-1, 2-3 and/or 2-4 have tremendous potential value in
calculating sorption constants for the great number of organic materials
where sorption data do not exist. Where sorption constants exist for a given
situation, these relationships allow extension to other soils and sediments.
The predicted Koc and Kp values are good first-order approximations, but they
should eventually be verified by actual sorption studies.
The limits of the validity of the Koc, water solubility, octanol-water
partition coefficient and organic carbon relationships (hydrophobic sorption)
are not fully known. It has been demonstrated (see Section 4.2) that the
limits are a function of both sorbate and sorbent properties. The concept of
hydrophobic sorption may not be valid for compounds that contain hydrophilic
functional groups. The presence of such groups may simultaneously increase
solubility and decrease sorption, thus maintaining the established Koc-water
solubility relationship (e.g., 6-aminochrysene or 2-aminoanthracene), or they
may increase solubility and dramatically increase sorption by forming a cation
as was the case with benzidine. It also appears that the concept of hydro-
phobic sorption may not be valid for sediments and soils that have low
organic carbon contents in combination with medium to high swelling clay
contents, particularly for compounds with low Koc values (see Section 4.2).
11
-------
SECTION 3
RECOMMENDATIONS
Additional research needs to be conducted to better define the adsor-
bate and adsorbent properties where hydrophobic adsorption is the dominant
adsorption process. If the Koc-Kow relationship (equation 2-3) and/or the
Koc-S relationship (equation 2-4) are to provide as much possible information
about the multitude of existing or new organic compounds, the limits of
validity of the two equations must be defined.
There appears to be no maximum Kow value nor minimum water solubility
where the relationships are not valid other than the limits imposed by
analytical sensitivity. In fact, for very insoluble organics where the limits
of analytical detection are approached in sorption experiments and where
impurities and degradation products present very difficult problems, the Koc-
Kow and Koc-S relationships may provide more reliable numbers than the actual
sorption experiments. The existing data suggest that there should exist a
minimum Kow value or maximum solubility such that compounds with greater Kow
values or lower water solubilities will be strictly hydrophobically sorbed.
For compounds with lower Kow values or higher water solubilities the com-
pounds may be strictly hydrophobically sorbed independent of soil properties
other than organic carbon or the compounds may be hydrophobically sorbed only
by selected soils and sediments.
The acetophenone and 1-naphthol data suggest that the ratio of organic
carbon to montmorillonite clay content may provide a method of predicting
when hydrophobic sorption will dictate the behavior of a compound. These
compounds were strictly hydrophobically sorbed above an organic carbon to
montmorillonite ratio (%OC •=• % montmorillonite) of 0.10 regardless of the
nature of the soil or sediment. The relationship between this ratio and
hydrophobic sorption needs further study to better define the critical ratio,
if one exists.
Much of the existing data in the published literature are in terms of
mass Kd or Kp values. It is recommended before equations 2-3 and 2-4 are
used that data be either in the form of linear Kp values or converted to
molar Kd values by the relationship of Osgerby (19):
„ n ... Mass Kd x Mol. wt1//n
Molar Kd = rrr: ,, ..
Mol. wt (3-1)
12
-------
SECTION
LABORATORY INVESTIGATIONS
4.1. ACETOPHENONE
Acetophenone was chosen to represent one class of compounds, the aro-
matic ketones, which have been shown to be present in coal gasification wastes
(2). The physical properties of acetophenone are given in Table 4.1.
TABLE 4.1. PHYSICAL PROPERTIES OF ACETOPHENONE
Structure
o
Molecular weight
Melting point (°C)a
Boiling point (°C)a
3,
Density
Flash point (°C)a
Heat of vaporization, AHv (cal/gmol)
aAldrich catalog, 1979-80
bCRC Handbook, 1975-76
Water solubility was determined to be 5,440 yg/ml by the procedure
given in Section 5.3. The octanol-water partition coefficient of acetophenone
was determined to be 38.6 by the procedure given in Section 5.2.
Batch equilibrium sorption isotherms were determined using ll*C-labeled
acetophenone (>99 percent pure) obtained from ICN Pharmaceuticals, Inc., and
13
-------
unlabeled acetophenone (>99 percent pure) from Eastman Kodak Co. Purity was
verified using thin-layer chromatography (see Section 5.1.2). A stock solution
(4,154 yg/ml) was prepared in ultrapure distilled water. The sorption iso-
therms were determined in triplicate on a 2:5 sample to solution ratio (10 g
soil/sediment sample and 25 ml acetophenone solution) with initial concentra-
tions of 138, 277, 554, 831 and 1,108 yg/ml. Samples were equilibrated in
stainless steel centrifuge tubes (aluminum foil-covered lids) in a tempera-
ture-controlled shaking water bath at 25°C for 24 hours. Initial and final
concentrations of acetophenone in the solution phase were determined by liquid
scintillation counting. The concentration of acetophenone in the soil or
sediment samples (yg/g) was determined by difference. A lltC mass balance was
determined on selected samples to verify that there was no loss of compound
from the system. Gas chromatography was used to determine if a significant
quantity of the acetophenone had been degraded. Retention times for the
parent compound and the compound present in the solutions equilibrated with
soil or sediment samples were identical, and no unidentified peaks were
observed. This was taken as evidence that no degradation of acetophenone had
occurred.
Sorption of acetophenone on the sediment and soil samples followed a
linear trend over the entire concentration range studied. Representative
isotherms are shown in Figure 4.1. Average values of the sorption isotherm
data for each soil and sediment are given in Table 4.2. The sorption
isotherms were described by the following equation:
Cs = Kp'Cw (4-1)
where Cs is the amount of compound sorbed by the soil or sediment in yg/g, Cw
is the equilibrium solution concentration in yg/ml, and Kp is the linear
partition coefficient.
The linear partition coefficients and Koc values for the sorption of
acetophenone are given in Table 4.3. The Kp values varied from a low of
0.07 for sample 8 to a high of 0.89 for sample 4.
Simple correlations between Kp and selected soil properties were
determined. These data indicated that the correlation between Kp and per-
centage organic matter was highly significant at the 1 percent level of
probability. The other factors tested, i.e., pH, CEC, % clay and % montmoril-
lonite, were nonsignificant. Regression of Kp against organic carbon content
(decimal equivalent) produced the following equation:
Kp = 35.0(%OC) r2 = 0.898 (4-2)
where 35.0 is the Koc value for acetophenone.
The Koc values obtained for the individual soils and sediments were
closely grouped around the regression value of 35.0 with the exception of
samples 6 and 9; these two samples have the smallest percent organic carbon
to percent montmorillonite ratios.
14
-------
1000-
0
200
400 600 800
Cw (/j,g /ml)'
1000
FIGURE 4.1. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF ACETOPHENONE BY
SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
15
-------
TABLE 4.2. ACETOPHENONE SORPTION ISOTHERM DATA3
Sample
B2
6
14
20
23
Cwb
(yg/ml)
112
233
475
704
943
111
219
444
645
870
130
260
519
792
1062
119
247
499
742
996
92
201
425
649
885
Csc
(yg/g)
67
110
198
319
411
67
144
275
465
594
21
44
87
98
115
49
73
136
223
279
117
189
323
456
558
Sample Cw
(Ug/ml)
4 95
198
405
615
816
8 122
267
541
814
1070
15 118
243
493
756
1004
21 90
196
417
629
822
26 93
203
439
652
884
Cs
(yg/g)
109
199
372
538
728
11
25
30
40
94
51
86
153
187
261
121
203
341
504
714
133
185
287
448
558
Sample Cw
(yg/ml)
5 97
211
448
676
916
9 135
265
539
811
1061
18 121
251
493
747
983
22 103
220
461
681
921
Cs
(yg/g)
104
164
263
387
480
8
30
38
50
117
45
64
151
209
312
89
143
233
374
466
aValues are averages of triplicate determinations.
°Cw is the equilibrium aqueous concentration.
GCs is the amount sorbed by the soil or sediment sample.
16
-------
TABLE 4.3. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR THE
SORPTION OF ACETOPHENONE BY SOILS AND SEDIMENTS
Sample Organic carbon Kp Koc
4
5
6
8
9
14
15
18
20
21
22
23
26
B2
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
1.21
0.89
0.56
0.68
0.07
0.09
0.12
0.27
0.30
0.29
0.85
0.53
0.68
0.66
0.44
43
24
95
48
82
25
28
46
22
45
31
29
45
36
Comparison of samples 6 and 23 illustrates the organic carbon/clay
interaction. Sample 6 gave an unexpectedly high Kp value (0.68) for its
organic carbon content (0.72%). This apparently aberrant result can be
partially explained by the high montmorillonite content (61%) of the sample
sorbing acetophenone in excess of its organic carbon content. Sample 23, by
contrast, had a similar Kp value (0.68) and yet was high in both montmoril-
lonite (58%) and organic carbon (2.38%). Hence, for this sample the organic
carbon appeared to mask the effect of the clay on sorbing acetophenone, and
the relationship between Kp and organic carbon content remained valid.
Stevenson (23) reported that the relative contributions of organic and
inorganic surfaces to adsorption depends on the extent to which the clay is
coated with organic substances. He considered clay-humus and clay alone as
two major types of adsorbing surfa.ces normally available to pesticides.
Hence clays should exhibit their maximum influence on sorption of nonpolar
compounds in the absence of adequate organic materials for coating the clays.
17
-------
4.2. 1-NAPHTHOL
1-Naphthol (a-naphthol) was chosen to represent the aromatic alcohols
or phenolic materials found in coal conversion waste streams (2). The physi-
cal properties of 1-naphthol are given in Table 4.4.
TABLE 4.4. PHYSICAL PROPERTIES OF 1-NAPHTHOL
Structure
Molecular weight
(Aldrich catalog, 1979-80)
Melting point (°C)
(Aldrich catalog, 1979-80)
Boiling point (°C) 278-280
(Aldrich catalog, 1979-80)
Heat of vaporization, AHv (cal/gmol) 14,205.6
(CRC Handbook, 1975-76)
Water solubility was determined to be 866 yg/ml by the procedure given
in Section 5.3. The octanol-water partition coefficient was determined to be
700 by the procedure given in Section 5.2.
Batch equilibrium sorption isotherms were determined using llfC-labeled
1-naphthol (>99% pure) from Aldrich Chemical Co. Purity of the original solu-
tions and the equilibrium isotherm solutions was verified by thin-layer chro-
matography. The sorption isotherms were determined in triplicate on a 1:10
soil to solution ratio (4.0 g soil/sediment and 40.0 ml solution) with initial
concentrations ranging from 86 to 690 pg/ml. Samples were equilibrated in
stainless steel centrifuge tubes (teflon-covered lids) in a temperature-con-
trolled shaking water bath at 25°C for 24 hours. Initial and final aqueous
phase concentrations of 1-naphthol were determined by liquid scintillation
counting. The concentration of 1-naphthol sorbed by the soil/sediment phase
was determined by difference. A 1'*C mass balance was calculated to verify
that there was no loss of the compound from the system. The llfC mass balance
was determined by converting the compound sorbed on the soil/sediment to 11*C02
using a Packard Model 306 sample oxidizer. No significant loss of 1-naphthol
was observed.
18
-------
Soil thin-layer chromatography (TLC) was used to study the effect of
solvent polarity on hydrophobia and nonhydrophobic sorption, Soil TLC plates
were prepared by spreading a uniform layer of soil-water slurry 0.5 mm thick
over 20x20-cm glass plates using the basic method of Helling and Turner (24).
The plates were dried in a desiccated chamber and spotted with llfC-labeled
1-naphthol using micropipette capillary tubes. Plates were developed in a
chromatographic tank with the appropriate solvent and set with X-ray film in
a darkroom. Rf values were determined by visual measurement of the developed
film and verified by scraping and counting 1-cm segments from the developed
plates in liquid scintillation vials containing 10 ml Aquasol (New England
Nuclear).
The results of the sorption experiments with 1-naphthol are given in
Tables 4.5 and 4.6. The isotherms were well represented by the Freundlich
equation:
Cs = Kd • Cw1/n (4-3)
where Cs is the amount of compound sorbed by the soil or sediment in ymoles/g,
Cw is the equilibrium solution concentration in ymoles/ml, and Kd and 1/n are
constants. The 1/n values ranged from 0.222 to 0.642, while Kd values varied
from 2.60 to 30.23. Representative isotherms are given in Figure 4.2, The
isotherms were non-linear, as expected from their 1/n values.
Ten of the sixteen samples produced Koc values (Table 4.6) which were
in good agreement with the Koc value (432) calculated from the octanol-water
partition coefficient (700) of 1-naphthol. [N.B. The bulk of the present in-
vestigation involved 14 soil/sediment samples. Two additional samples, #13
and #B1, not referred to elsewhere in this report, were included in the
1-naphthol sorption isotherm determinations.] The remaining six samples gave
Koc values that were much larger than the predicted value. This is further
illustrated in Figure 4.3 which shows the relationship between Kd and the
organic carbon content of the soils/sediments. The Kd values of ten samples
were highly correlated (r2 = 0.876) with organic carbon content, whereas the
Kd values of the other six samples were not. The slope of the line in Figure
4.3 is equivalent to Koc and gave a value of 522 which is in good agreement
with the predicted value.
The justification for excluding the six samples with high Koc values
can be seen in Figure 4.4. This figure presents Koc as a function of the
organic carbon to montmorillonite ratio of the soil or sediment. For 1-naph-
thol, there appeared to be two distinct families of data. One family of ten
samples formed a line that was basically parallel to the %OC/%Mont axis and
hence was independent of that variable. Those were the same soils and sedi-
ments whose Koc values converged on the predicted value and thus appeared to
hydrophobically sorb 1-naphthol. The other six samples produced a line that
appeared to be a function of the organic carbon to montmorillonite ratio. The
data suggest that clay may sorb 1-naphthol in sediments with low to medium
organic carbon contents, but may not be a major factor controlling sorption in
soils or sediments with high organic carbon contents. Comparison of samples
23 and 26 which have high montmorillonite contents, but in combination with
high organic carbon contents, with the six samples that gave high Koc values
19
-------
TABLE 4.5. 1-NAPHTHOL SORPTION ISOTHERM DATAa
Sample
B2
6
14
20
23
Cwb
(ymol/ml)
0.06
0.37
1.20
1.95
2.90
0.010
0.023
0.234
0.875
1.52
0.24
0.56
1.18
1.86
2.53
0.004
0.010
0.104
0.264
0.617
0.08
0.32
0.92
1.96
2.68
Csc
(ymol/g)
5.40
8.32
11.93
16.43
18.82
5.88
11.73
21.59
27.15
32.62
1.32
1.89
3.18
3.92
4.75
2.90
5.78
10.71
14.99
17.35
5.25
8.81
14.88
16.45
21.26
Sample Cw
(ymol/ml)
4 0.03
0.13
0.58
1.33
2.00
8 0.44
0.94
1.99
3.10
4.15
15 0.002
0.009
0.038
0.221
0.430
21 0.19
0.58
1.41
2.29
3.26
26 0.15
0.49
1.29
2.07
3.12
Cs
(ymol/g)
5.72
10.65
18.16
22.59
27.82
1.55
2.60
3.99
4.91
6.38
2.91
5.79
11.29
15.34
19.21
3.73
6.15
9.87
13.03
15.28
4.56
7.10
11.04
15.20
16.62
Sample Cw
(ymol/ml)
5 0.21
0.57
1,45
2.32
3.17
9 0.01
0.04
0.62
1.31
2.38
18 0.05
0.22
1.00
1.92
2.98
22 0.23
0.60
1.43
2.34
2.59
Cs
(ymol/g)
3.95
6.33
9.55
12.83
16.89
5.84
11.52
17.74
22.75
24.04
5.56
9.83
14.06
16.49
18.31
3.71
5.97
9.66
12.45
21.94
aValues are averages of triplicate determinations.
°Cw is the equilibrium aqueous concentration.
cCs is the amount sorbed by the soil or sediment sample.
20
-------
TABLE 4.6. FREUNDLICR SORPTION CONSTANTS, ,r* VALUES AND Koc VALUES
FOR THE SORPTION OF 1-NAPHTHOL BY SOILS AND SEDIMENTS
Sample K (molar) l/n(molar) r2 Koc
4
5
6
8
9
13
14
15
18
20
21
22
23
26
Bl
B2
15.99
8.17
30.23
2.60
17.18
9.96
2.81
25.65
13.87
21.39
8.40
8.79
14.01
10.23
8.15
9.96
0.441
0.550
0.310
0.609
0.222
0.357
0.563
0.318
0.283
0.313
0.501
0.642
0.387
0.442
0.549
0.357
0.980
0.992
0.941
0.996
0.983
0.985
0.991
0.935
0.997
0.905
1.000
0.923
0.984
0.992
0.979
0.985
772
358
4,198
1,733
15,618
328
585
2,700
2,102
1,645
447
526
589
691
905
823
illustrates the interaction of clay and humus. The higher organic carbon con-
tents of samples 23 and 26 probably masked the effect of the clay, lowering
the amount of sorption to a level controlled by the organic carbon contents
of the samples. Shin (25) reported an increase in the sorption of DDT with
partial removal of soil organic matter. Stevenson (23) reported that the
relative contribution of organic and inorganic surfaces to sorption depends
on the extent to which the clay is coated with organic substances. He con-
sidered humus-clay and clay alone as two major types of sorbing surfaces nor-
mally available to organic sorbates.
In earlier work with the same sediment samples used in this study,
acetophenone was shown to be hydrophobically sorbed by all but two of the
samples, 6 and 9, The degree of departure of predicted and measured Koc
values for acetophenone was much less than found with the six skmples in the
1-naphthol experiments. Hydrophobic sorption was implied when there was a
high degree of correlation between a compound's Kow value and sorption ex-
pressed on an organic carbon basis (Koc), The 1-naphthol and acetophenone
21
-------
2 3
Cw (/imole/ml)
22
FIGURE 4.2. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 1-NAPHTHOL BY
SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
22
-------
o:
<
o
40
30
20
10
0
Kd=5.22 %OC r =0.876
o-SAMPLES INCLUDED IN Kd vs %OC CORRELATION
•—SAMPLES EXCLUDED
o
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
%oc
FIGURE 4.3. RELATIONSHIP BETWEEN MOLAR Kd (.FOR THE SORPTION OF 1-NAPHTHOL) AND %OC FOR TEN SOIL AND
SEDIMENT SAMPLES (o) SHOWING HIGH CORRELATION BETWEEN THE TWO PARAMETERS AND FOR SIX
SAMPLES (•) THAT GAVE HIGH Koc VALUES
-------
15,000
13000
11,000
9,000
7,000
5,000
3,000
•-SAMPLES EXCLUDED FROM Koc CALCULATIONS
o-SAMPLES INCLUDED IN Koc CALCULATIONS
o
0.2
0.3
0.4
0.5
0.6
%oc
%MONT
FIGURE 4.4.
RELATIONSHIP BETWEEN Koc (FOR THE SORPTION OF 1-NAPHTHOL) AND
THE %OC/MONTMORILLONITE RATIO OF SOILS AND SEDIMENTS FOR TEN
SAMPLES (0) SHOWING HIGH CORRELATION BETWEEN Kd AND %OC AND
FOR SIX SAMPLES (•) THAT GAVE HIGH Koc VALUES
24
-------
data suggest that there is a lower limit (Kow value) where the correlation
between Kow and Koc may not hold. The lower limit is not strictly a function
of the compound's water solubility or its octanol-water partition coefficient,
but is also a function of soil or sediment properties« Acetophenone has a
water solubility of 5440 yg/ml and a Kow of 38.6 while 1-naphthol has a water
solubility of 866 yg/ml and a Kow of 700. Despite the more polar nature of
acetophenone in aqueous solutions, acetophenone appears to be hydrophobically
sorbed by soils and sediments that do not hydrophobically sorb 1-naphthol.
For 1-naphthol the Koc-Kow relationship may or may not hold for samples with
organic carbon to montmorillonite ratios below 0.10; for acetophenone the re-
lationship appears valid until a ratio of 0.015 or less is reached.
The role of the solute-solvent interaction in hydrophobic sorption is
illustrated by a soil thin-layer chromatographic (24,26) study of 1-naphthol,
dicamba (3,6-dichloro-2-methoxybenzoic acid) and 3-methylcholanthrene in dif-
ferent solvent systems (Figure 4.5). In the pure water system 1-naphthol and
3-methylcholanthrene were strongly sorbed and hence showed little or no move-
ment, while dicamba which is a more polar and hence more water-soluble com-
pound had an Rf value close to 1.0. Increasing the percentage of ethanol in
the mobile phase resulted in higher Rf values for 1-naphthol and 3-methyl-
cholanthrene and decreased movement or lower Rf values for dicamba. As the
percentage of ethanol increased, the mobile phase became a continually better
solvent for 1-naphthol and 3-methylcholanthrene, .and hence a stronger and
stronger solute-solvent interaction occurred resulting in decreased sorption.
The effect of the composition of the mobile phase on dicamba, a polar material,
was the opposite, as expected. As the percentage of ethanol increased, the
mobile phase became less polar and hence a poorer solvent for dicamba. Sorp-
tion of dicamba increased and the Rf value dropped to less than 0.15 as the
solute-solvent interaction weakened.
The sorption of 1-naphthol on ten of the sixteen samples appeared to be
an example of hydrophobic sorption. Sorption of this type is the result of
a weak solute-solvent interaction and the subsequent sorption of the compound
by humic materials. Factors that increase the affinity of the solute for the
solvent result in decreased sorption and increased mobility of the solute.
For compounds such as 1-naphthol and acetophenone the degree and type
of sorption appears to be both a function of the water solubility or Kow value
of the compound and a function of soil or sediment properties. One can specu-
late that as the water solubilities of compounds decrease, a point is reached
where only hydrophobic sorption functions and sorption can be .accurately .pre-
dicted from Kow values. For compounds of higher water solubility they may be
completely, partially or not at all hydrophobically sorbed.
25
-------
\ /a-NAPHTHOL
3-METHYLCHOLANTHRENE
_J I I L
40
60 80
100
%ETHANOL IN WATER
FIGURE 4.5. EFFECT OF VARYING THE ETHANOL:WATER RATIO IN THE SOLVENT
SYSTEM ON SOIL TLC Rf VALUES FOR DICAMBA, a-NAPHTHOL AND
3-METHYLCHOLANTHRENE
26
-------
4.3. BENZIDINE
Benzidine (4,4'-diaminobiphenyl) and compounds of similar chemical and
physiological properties are potential waste products of coal conversion
plants ( 2 ) and other industrial activities. The introduction of benzidine,
an aromatic amine, into the environment is reason for concern since benzidine
has been identified as a potent carcinogen (27,28,29,30). The physical
properties of benzidine are given in Table 4.7.
TABLE 4.7. PHYSICAL PROPERTIES OF BENZIDINE
Structure
Molecular weight
(CRC Handbook, 1975-76)
Melting point (°C)
(CRC Handbook, 1975-76)
Boiling point (°C)
(CRC Handbook, 1975-76)
H,N
(Korenman and Nikolaev (31))
pKb2
(Korenman and Nikolaev (31))
184.24
125
400
4.3
3.3
The interaction of benzidine with clays, especially montmorillonite,
has been extensively studied as benzidine forms a blue-colored complex with
the clay upon sorption. The benzidine-clay complex is the result of the
reversible oxidations of the benzidine by ferric iron or other electron
donors with stabilization of the product by sorption to the clay. In the
absence of clay or other suitable sorbents benzidine is irreversibly oxidized
to a brown degradation product. The blue color of the benzidine-clay complex
arises from the semiquinoidal radical cation of benzidine. A yellow
quinoidal divalent cation is formed in acidic aqueous solutions of benzidine
and clay. Benzidine may also form cations by protonation of the amino groups.
The early research on benzidine-clay reactions has been reviewed by Solomon
et al. ( 32 ) and Theng ( 33 ). Tennakoon et at. ( 34 , 35 , 36 ) discuss the
proposed mechanism of benzidine-clay reactions.
Batch equilibrium sorption isotherms were performed using 14C-labeled
benzidine obtained from New England Nuclear. Unlabeled benzidine (RFR Corp. ,
Hope, RI) was used to adjust the activity of the labeled compound. A stock
27
-------
aqueous solution of benzidine containing 270 pg/ml and 390Q dpm/ml was pre-
pared using ultrapure water. The purity of the stock solution was determined
to be at least 98% by thin-layer chromatography. The sorption isotherms were
determined in triplicate using 4g:40 ml soil:solution ratio. Initial con-
centrations ranged from 67 to 270 yg/ml. A few samples exhibited very strong
sorption resulting in extremely low levels of benzidine left in solution.
For these samples, isotherms were determined by varying the amount of soil
or sediment from 0.25 g to 0.40 g and keeping the initial benzidine con-
centration constant at 270 yg/ml (40 ml).
The samples were equilibrated in stainless steel centrifuge tubes at
25°C for 20 hours in a temperature-controlled shaking water bath. After
equilibration the phases were separated by centrifugation and the aqueous
phase was sampled for scintillation counting. The ^C activity was deter-
mined using a Packard model 3330 liquid scintillation spectrometer. The
amount sorbed was calculated as the difference between initial and
equilibrium concentrations.
The extent of benzidine degradation in the equilibrium solutions was
determined by gas chromatography. A Packard model 417 gas chromatograph with
a flame ionization detector and a 2-m SE-30 column with a flow rate of 16ml/
min N2 carrier gas was used. The system was standardized using known
solutions of benzidine and diphenylazine, a suspected degradation product.
No extraneous peaks were observed for the equilibrium isotherm solutions.
The sorption of benzidine by soils and sediments produced isotherms
which were well represented by the Freundlich equation:
Cs = Kd • Cw1'11 (4-3)
where Cs is the concentration of benzidine in nmoles/g of soil or sediment,
Cw is the equilibrium solution concentration in nmoles/ml and Kd and 1/n are
constants. Representative isotherms are shown in Figure 4.6 and sorption
constants are given Table 4.8. Average values for the sorption data are
given in Table 4.9. Attempts to fit the data to the Langmuir equation gave
poor fits both visually and statistically.
Neither Freundlich constant was highly correlated with soil or
sediment properties. This was probably due to the fact that variation
between isotherms for different soils and sediments was expressed in two
constants, Kd and 1/n. Small changes in the exponential constant 1/n can
result in large changes in the Kd values and hence poor correlation with soil
or sediment properties. To overcome this difficulty the sorption data were
fit to a Freundlich equation (Kd2) where the exponential constant (1/n) had
a value of 0.5. The mean of the 1/n values in Table 4.8 was 0.515.
Cs = Kd2 • Cw°'5 (4_4)
The resulting Kd2 values and correlation coefficients for the fit of
the data are given in Table 4.10. The Kd2 values were highly correlated
(r2 = 0.92) with hydrogen ion activities as calculated from pH measurements.
28
-------
10,000
O
E
c
CO
O
8,000
6,000
4,000
2,000
B2
21
200
400
600
800
1000
Cw (nmoles/ml)
FIGURE 4.6. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF BENZIDINE BY
SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
29
-------
TABLE 4.8, FREUNDLICH CONSTANTS (Kd and 1/n) AND .r2 VALUES
FOR THE SORPTION OF BENZIDINE BY SOILS AND SEDIMENTS (MOLAR BASIS)
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
Kd
(molar)
500.4
570.5
589.4
1657 . 8
86.2
551.7
3941.3
1705.4
564.6
2332.9
49.6
73.9
1072.7
108.2
1/n
(molar)
0.423
0.513
0.468
0.568
0.496
0.372
0.664
0.266
0.413
0.426
0.694
0.640
0.569
0.656
r2
0.91
0.96
0.97
0.94
0.83
0.94
0.93
0.93
0.96
0.91
0.97
0.95
0.96
0.89
The data suggest that the pH of the system controls the sorptlon of the
benzidine by controlling the amount of benzidine in the ionized form in
solution.
The dependence of sorption on pH can further be illustrated by the
results of experiments where sorption of benzidine by samples 6 and 14 was
determined before and after adjustment of pH (Figure 4.7). For these
experiments pH was adjusted with either concentrated NaOH or HC1, and the
resultant sorption and pH values were measured after equilibration under the
same sorption isotherm conditions described above. Sorption increased
as pH decreased, that is, as a greater percentage of the total benzidine
occurred as a charged (cationic) species.
Benzidine, as already noted, can exist in solution as both an ionized
(cationic) species and a neutral species. The distribution of aqueous
benzidine between the two forms is a function of solution pH. Both species
are subject to sorption, although the cationic form should be sorbed to a
much greater extent.
Karickhoff et al. ( 15 ) and Khan et al. ( 16 ) established a
relationship between the octanol-water partition coefficient (Kow) of a
30
-------
TABLE 4,9. BENZIDINE SORPTION ISOTHERM DATA3
Sample Cwb Csc
(nmol/ml) (nmol/g)
B2
6
14
20
23
17
64
187
354
467
1
4
11
25
47
0.11
1.67
2.75
3.88
5.17
1.42
1.9
5
25
111
1.6
8
18
53
80
1419
2533
4476
5984
8026
1577
3140
6239
9272
12233
1589
3159
6323
9487
12649
1573
3153
6296
9276
11594
1569
3099
6171
8994
11902
Sample Cw Cs
(nmol/ml) (nmol/g)
4 8
20
69
166
262
8 87
210
454
734
995
15 0.63
6
78
215
412
21 69
149
355
539
771
26 41
102
261
410
545
1504
2976
5662
7866
10084
718
1080
1793
2186
2746
1579
3110
5573
7377
8576
896
1683
2801
4136
4987
1178
2155
3734
5428
7246
Sample Cw Cs
(nmol/ml) (nmol/g)
5 8
27
138
215
360
9 8
47
218
39_6
620
18 14
39
159
340
502
22 69
141
364
559
754
1509
2901
4966
7371
9100
1509
2705
4169
5564
6502
1448
2787
4764
6124
7680
899
1764
2698
3938
5124
aValues are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
GCs is the amount sorbed by the soil or sediment sample.
31
-------
TABLE 4.10. MODIFIED FREUNDLICH PARTITION CONSTANTS (1/n - 0,5)
FOR THE SORPTION OF BENZIDINE (Kd2) AND IONIZED BENZIDINE (Kd3)
BY SOILS AND SEDIMENTS (MOLAR BASIS)
Samp le
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
Kd2
(molar)
339.1
609.8
498.0
2851.8
85.9
259.8
8037.2
473.8
344.5
1558.8
167.6
177.4
1790.3
276.7
2
r
0.99
0.99
0.99
0.98
0.98
0.98
0.98
0.95
0.99
0.98
0.98
0.98
0.98
0.96
Kd3
(molar)
3,552
33,542
18,206
165,780
8,693
27,138
13,063
26,132
18,352
6,347
7,048
7,116
28,208
14,335
2
r
0.99
0.99
0.99
0.98
0.98
0.98
0.98
0.95
0.99
0.98
0.98
0.98
0.98
0.96
nonpolar neutral compound and the linear partition coefficient for the
sorption of the compound by soils and sediments:
log (Kp/OC) = log Kow - 0.21 (4-5)
where Kp is the linear sorption or partition coefficient of a compound on a
particular soil or sediment and OC is the organic carbon content of the soil
or sediment expressed on a fractional basis.
The relationship expressed in equation 4-5 has been shown to apply to
unionized hydrophobic organic compounds and is attributed to the hydrophobic
or nonpolar bonding ( 14 ) of the compound to the soil or sediment organic
matter (15,16).
If the assumption is made that neutral benzidine will bind via
hydrophobic bonding to soil organic matter, then equation 4-5 can be used to
calculate the individual Kp values for the sorption of neutral benzidine by
the soils and sediments. Calculations were based on the soil and sediments'
organic carbon contents and the Kow (46.0) of benzidine. Three equations may
32
-------
5
4
O
O
O
— 2
I
0
8 9
PH
10
ii
12
FIGURE 4.7. EFFECT OF pE ON THE SORPTIQN OF EENZIDINE RY SOILS AND
SEDIMENTS
Numbers refer to soil or sediment samples.
33
-------
then be written to model the sorption of benzidine by soils and sediments:
bzn(sorbed) = Kp-bzn(aq) (4-6)
bzn (aq) + 2H+ = bzn H*+(aq) K = Kbi'Kb2 (4-7)
bzn H|+(sorbed) = Kd -bzn H^aq)0'5 (4-8)
Using Kp values calculated from equation 4-5, H activities calculated from
measured pH values, and the total amount of benzidine added, equations 4-6,
4-7, and 4-8 can be solved to yield the Freundlich sorption constant Kd3
(1/n = 0.5) for the sorption of the ionized benzidine by each soil or sedi-
ment (Table 4.10).
The Kd3 values thus obtained were significantly correlated with the
surface area of the soils and sediments (r2 = 0.72). Addition of organic
carbon content and the interaction between surface area and organic carbon to
the the regression equation improved the correlation (r = 0.86). The
regression coefficient for organic carbon content was non-significant while
the regression coefficient of the interaction was significant (t = -2.379)
and negative. This suggests that organic materials coat clay particles and
lower the sorption capacity of the soil for ionized benzidine. The clay-
organic matter interaction is illustrated by comparing the Kd3 values for
samples 6 and 23. Both samples have comparable textures and clay mineralogy.
Sample 23, however, has a higher organic carbon content which appears to mask
the clay and consequently this sample sorbs substantially less of the ionized
benzidine. The effect of surface area on benzidine sorption is illustrated
in Figure 4.6. At any given pH, sample 6 which contains predominantly
montmorillonite clays sorbs greater amounts of benzidine than sample 14 which
contains predominantly kaolinite clays.
The sorption of benzidine by "whole" soils and sediments was con-
trolled primarily by the concentration of the ionized species. Sorption was
highly correlated with pH since pH controlled the ratio of neutral to ionized
benzidine in the aqueous phase. When the isotherms were corrected for
sorption of the neutral species, sorption of the ionized benzidine was highly
correlated with surface area and negatively correlated with organic carbon
content. The organic matter appeared to coat and hence mask ionized benzidine
sorption sites. These experiments suggest that extrapolation of sorption data
from studies involving only clay minerals to situations involving "whole"
soils or sediments may produce erroneous results.
34
-------
4.4 PYRENE
Pyrene, 3-methylcholanthrene, dibenz[a,7z]anthracene and 7,12-dimethyl-
benz[a]anthracene were chosen as representatives of the polynuclear aromatic
hydrocarbons. The compounds represent different configurations of four and
five-ring structures. The factors affecting the sorption of these compounds
are discussed in Section 4.7.
The physical properties of pyrene are given in Table 4.11.
TABLE 4.11. PHYSICAL PROPERTIES OF PYRENE
Structure
Molecular weight 202.26
(CRC Handbook, 1975-76)
Melting point (°C) 156
(CRC Handbook, 1975-76)
Boiling point (°C) 393
(CRC Handbook, 1975-76)
Density 1.271
(CRC Handbook, 1975-76)
The octanol-water partition coefficient (Kow) of pyrene was determined
over a range of aqueous concentrations using radiolabeled compound and the
procedure outlined in Section 5.2. A Kow value of 124,000 was obtained for
pyrene. The water solubility of pyrene was determined to be 0.135 ug/ml by
the procedure described in Section 5.3.
Batch equilibrium sorption isotherms were determined using 3H-labeled
pyrene that had been tritiated by the method outlined in Section 5.1.3. The
unlabeled pyrene used in the tritiation procedure was obtained from Aldrich
Chemical Co. (>99% pure). The resulting generally-labeled 3H-pyrene was puri-
fied by microdistillation followed by preparative thin-layer chromatography.
35
-------
An aqueous solution was prepared by evaporating (under a stream of N£
gas) an appropriate quantity of 3H-labeled pyrene stock solution on the lower
walls of a glass container, adding ultrapure water and stirring for 24 hours.
The resulting solution was filtered through a 0.2y Nuclepore filter to remove
any undissolved particles and diluted with ultrapure water to the desired con-
centrations.
The sorption isotherms were determined in triplicate on a 1:10 soil to
solution ratio, with initial pyrene concentrations ranging from 10 to 80 Mg/ml
(the upper initial concentration representing ^59% of the maximum water solu-
bility level). Isotherm suspensions were shaken in stainless steel centrifuge
tubes with teflon-covered lids in a temperature-controlled shaking water bath
at 25°C for 24 hours.
Initial and final aqueous phase concentrations of pyrene were deter-
mined by liquid scintillation counting. The amount of pyrene sorbed by the
soil/sediment phase was determined from the difference between the initial
and final aqueous phase concentrations. No degradation products were found in
either phase when analyzed by the procedure described in Section 5.4.1.
The sorption of pyrene by the soils and sediments produced linear sorp-
tion isotherms over the entire range of concentrations studied. Typical iso-
therms are shown in Figure 4.8. Average Cw and Cs values for the sorption of
pyrene by the soils and sediments are given in Table 4.12. The data gave good
fits to the Freundlich sorption isotherm equation:
Cs = Kd • Cw1/n (4-3)
Kd values (Table 4.13) ranged from 79 to 1191; the 1/n values were all close
to unity. The data gave equally good fits (Table 4.14) to the modified
Freundlich equation where 1/n was forced to equal unity. Koc values calcu-
lated from the linear partition coefficients (Kp) and the respective organic
carbon contents of the sediments and soils are also included in Table 4.14.
Regression of Kp against the organic carbon contents of the sediments and
soils produced a Koc value of 63,400 (r2 = 0.965).
36
-------
800-
18
~ 600h
400h
200-
8
0 0,2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
Cw(ng/ml)
FIGURE 4.8. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF PYRENE BY
SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
37
-------
TABLE 4.12. PYRENE SORPTION ISOTHERM DATAa
Sample
B2
6
14
20
23
Cwb
(ng/ml)
0.128
0.245
0.441
0.722
0.989
0.124
0.263
0.495
0.754
1.010
0.345
0.688
1.253
2.184
2.995
0.137
0.257
0.542
0.813
1.137
0.096
0.176
0.292
0.440
0.587
Csc
(ng/g)
95.0
190.1
380.6
570.3
760.1
95.0
189.9
380.1
570.0
759.9
92.8
185.6
372.5
555.7
740.1
94.9
189.9
379-6
569.4
758.6
95.3
190.7
382.1
573.2
764.1
Sample Cw
(ng/ml)
4 0.094
0.179
0.343
0.491
0.698
8 0.657
1.421
3.188
5.145
7.495
15 0.123
0.243
0.509
0.747
1.027
21 0.097
0.197
0.352
0.531
0.709
26 0.111
0.199
0.382
0.562
0.759
Cs
(ng/g)
95.3
190.7
381.6
572.6
763.0
89.7
178.3
353.1
526.1
695.1
95.0
190.1
379.9
570.0
759.7
95.3
190.5
381.5
572.2
762.9
95.1
190.5
381.2
571.9
762.4
Sample Cw
(ng/ml)
5 0.084
0.163
0.300
0.444
0.585
9 1.126
2.429
4.061
7.128
8.153
18 0.187
0.364
0.688
1,076
1.410
22 0.154
0.271
0.500
0.740
0.984
Cs
(ng/g)
95.4
190.9
382.0
573.1
764.1
85.0
168.2
344.4
506.2
688.5
94.4
188.9
378.1
566.7
755.9
94.7
189.8
380.0
570.1
760.2
aValues are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
cCs is the amount sorbed by the soil or sediment sample.
38
-------
TABLE 4.13. FREUNDLICH SORPTION CONSTANTS AND CORRELATION COEFFICIENTS
(Kd, 1/n and r2) AND THE MODIFIED FREUNDLICH PARTITION CONSTANTS
(Kp, 1/n = 1) FOR THE SORPTION OF PYRENE BY SOILS AND SEDIMENTS
Sample
B2.
4
5
6
8
9
14
15
18
20
21
22
23
26
Kd
774
1098
1191
633
125
79
285
783
509
747
1159
811
1130
1023
1/n
1.022
1.020
1.041
0.943
0.876
0.953
0.967
0.977
0.989
0.987
1.053
1.026
1.063
1.044
r2
0.988
0.995
0.981
0.964
0.989
0.979
0.978
0.994
0.995
0.986
0.990
0.977
0.942
0.994
Kp
760
1065
1155
614
101
71
277
783
504
723
1119
806
1043
994
39
-------
TABLE 4.14. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR THE
SORPTION OF PYRENE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
760
1065
1155
614
101
71
277
783
504
723
1119
806
1043
994
Koc
63,991
53,019
52,250
87,847
83,333
71,818
59,271
82,453
77,182
57,469
61,628
48,557
47,487
69,108
40
-------
4.5. 7,12-DIMETHYLBENZ[a]ANTHRACENE
7,12-Dimethylbenz[a]anthracene (9,10-dimethyl-l,2-benzanthracene, DMBA)
was chosen as one of four compounds representing the polynuclear aromatic
hydrocarbons. The physical properties of DMBA are given in Table 4,15,
TABLE 4.15. PHYSICAL PROPERTIES OF 7,12-DIMETHYLBENZ[a]ANTHRACENE
Structure
Molecular weight
(CRC Handbook, 1975-76)
Melting point .(°C) 122-123
(CRC Handbook, 1975-76)
The octanol-water partition coefficient of DMBA was determined over a
range of aqueous concentrations using radiolabeled compound and the procedure
described in Section 5.2. A Kow value of 953,000 was obtained. The water
solubility of DMBA was determined to be 0.0244 Ug/ml by the procedure given
in Section 5.3.
Batch equilibrium isotherms were determined using 1'*C-labeled DMBA ob-
tained from New England Nuclear. Purity of the radiolabeled compound was
verified by thin-layer chromatography. Appropriate amounts of DMBA were
plated from acetone solution onto the walls of stainless steel centrifuge
tubes using the procedure of Karickhoff et al. (15) for hydrophobic compounds.
These amounts represented the initial aqueous phase concentrations (2.54 to
12.27 ng/ml) that would have been present if the compound had been added as
aqueous solution. Exact values for initial aqueous concentrations were deter-
mined by pipetting the same amounts of stock solution into scintillation
vials for counting as were pipetted into the tubes for the isotherm determi-
nation. Sorption isotherms were determined in triplicate using a 4 g:40 ml
soil to solution ratio. The suspensions were shaken in the centrifuge tubes
with teflon-covered lids in a temperature-controlled shaking water bath at
25°C for 20 hours. The phases were separated by centrifugation.
Initial and final aqueous phase concentrations of DMBA were determined
by liquid scintillation counting. The amount of DMBA sorbed by the soil/sedi-
41
-------
ment phase was calculated from the difference between Initial and final radio-
activity levels in the aqueous phase, Final solution concentrations were cor-
rected for radiolabeled impurities and/or degradation products by the proce^
dure outlined in Section 5.4.1.
The sorption of DMBA by the soils and sediments produced linear iso-
therms over the entire concentration range studied. Representative isotherms
are shown in Figure 4.9. Average values for the sorption isotherm data for
each soil and sediment are given in Table 4.16. The sorption isotherms were
described by the following equation:
Cs = Kp • Cw (4-1)
where Cs is the amount of DMBA sorbed by the soil or sediment in ng/g, Cw is
the equilibrium solution concentration in ng/ml, and Kp is the linear parti-
tion coefficient.
The linear partition coefficients and Koc values for the sorption of
DMBA are given in Table 4.17. The Kp values varied from a low of 562 to a
high of 6777. Regression of Kp against the organic carbon content of the
soils and sediments produced a Koc value of 225,308 (r2 = 0.908). The sorp-
tion of DMBA was not highly correlated with other soil or sediment properties
such as pH, CEC, clay content or mineralogy.
The sorption of DMBA is discussed in Section 4.7 along with sorption
of the other three polynuclear aromatic hydrocarbons studied.
42
-------
CO
O
0.02 0.04 0.06 0.08
0.10
0.12
Cw(ng/ml)
FIGURE 4.9. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 7,12-DIMETHYL-
BENZ[a]ANTHRACENE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
43
-------
TABLE 4.16. 7,12-DIMETHYLBENZ[a]ANTHRACENE SORPTION ISOTHERM DATA3
Sample Cw
(ng/ml)
B2 0.0164
0.0225
0.0301
0.0411
0.0459
6 0.0298
0.0414
0.0604
0.0656
0.0785
14 0.0493
0.1016
0.1229
0.1707
0.1922
20 0.0169
0.0346
0.0429
0.0641
0.0673
23 0.0055
0.0092
0.0107
0.0129
0.0172
Csc
(ng/g)
24.0
48.4
72.7
97.0
121.4
23.4
47.6
71.4
95.8
119.8
23.2
46.2
70.2
93.4
117.3
24.0
47.8
72.1
95.9
120.3
24.2
48.6
73.0
97.5
121.7
Sample Cw
(ng/ml)
4 0.0145
0.0242
0.0270
0.0366
0.0403
8 0.0473
0.0770
0.1217
0.1499
0.9776
15 0.0089
0.0140
0.0194
0.0258
0.0313
21 0.0055
0.0095
0.0119
0.0170
0.0222
26 0.0089
0.0159
0.0186
0.0255
0.0313
Cs
(ng/g)
24.0
48.2
72.7
96.9
121.4
22.6
45.9
68.6
92.0
115.4
24.3
48.7
73.1
97.5
121.9
24.3
48.7
73.2
97.5
121.8
24.3
48.6
73.1
97.4
121.8
Sample Cw
(ng/ml)
5 0.0077
0.0122
0.0141
0.0182
0.0206
9 0.0246
0.0485
0.0684
0.0942
0.1055
18 0.0167
0.0310
0.0409
0.0518
0.0562
22 0.0117
0.0227
0.0282
0.0342
0.0427
Cs
(ng/g)
24.2
48.6
73.1
97.4
121.9
23.0
46.0
69.3
92.2
116.0
23.9
47.9
72.2
96.3
120.7
24.1
48.2
72.5
96.9
121.1
Values are averages of triplicate determinations.
bCw is the equilibrium aqueous concentration.
cCs is the amount sorbed by the soil or sediment sample.
44
-------
TABLE 4.17.. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR THE
SORPTION OF 7,12-DIMETHYLBENZla]ANTHRACENE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
2371
2646
5210
1346
611
1028
562
3742
1895
1617
5576
2679
6777
3740
Koc
195,998
127,812
228,499
186,986
407,496
934,225
117,161
393,907
287,196
124,347
296,580
160,391
284,743
252,735
45
-------
4.6. DIBEMZ[a,h]ANTHBACENE
Dibenz [a., ft] anthracene (1,2,5,6-dibenzanthracene) was chosen as a repre-
sentative polynuclear aromatic hydrocarbon containing five aromatic rings.
Dibenzanthracene is the least water-soluble and hence most hydrophobic of the
compounds used in this study. The physical properties of dibenz[a,h]anthra-
cene are given in Table 4.18.
TABLE 4.18. PHYSICAL PROPERTIES OF DIBENZ[o,7z]ANTHRACENE
Structure
Molecular weight 278.36
(CRC Handbook, 1975-76)
Melting point (°C) 269-270
(CRC Handbook, 1975-76)
Boiling point (°C) 524
(Aldrich catalog, 1979-80)
The octanol-water partition coefficient for dibenzanthracene was de-
termined over a range of aqueous concentrations with radiolabeled compound
using the procedure described in Section 5.2. A Kow value of 3,170,000 was
obtained. The water solubility of dibenzanthracene was determined to be
0.00249 yg/ml by the procedure outlined in Section 5.3.
Batch equilibrium isotherms were determined using 3H-labeled dibenzan-
thracene obtained from New England Nuclear. Purity of the radiolabeled com-
pound was verified by thin-layer chromatography. Appropriate amounts of di-
benzanthracene were plated from acetone solution onto the walls of the stain-
less steel centrifuge tubes using the procedure of Karickhoff et at, (15) for
hydrophobic compounds. These amounts represented the initial aqueous phase
concentrations (0.97 to 7,28 ng/ml) that would have been present if the com-
pound had been added as aqueous solution. Exact values for initial aqueous
concentrations were determined by pipetting the same amounts of stock solution
into scintillation vials for counting as were pipetted into the tubes for the
46
-------
isotherm determination. Sorption isotherms were determined in triplicate
using a 2 g:40 ml soil to solution ratio. The suspensions were shaken in the
centrifuge tubes with teflon-covered lids in a temperature-controlled shaking
water bath at 25°C for 24 hours. The phases were separated by centrifugation.
Initial and final aqueous phase concentrations of dibenzanthracene were
determined by liquid scintillation counting. The amount of dibenzanthracene
sorbed by the soil/sediment phase was calculated from the difference between
initial and final radioactivity levels in the aqueous phase. Final solution
concentrations were corrected for radiolabeled impurities and/or degradation
products by the procedure outlined in Section 5.4.1.
Sorption of dibenzanthracene by the sediments and soils produced
linear isotherms over the entire range of concentrations studied. Representa-
tive isotherms are shown in Figure 4.10.
Average values for individual isotherms are given in Table 4.19. The
sorption isotherms were described by the following equation:
Cs = Kp • Cw (4-1)
where Cs is the amount of dibenzanthracene sorbed by the soil or sediment, Cw
is the equilibrium solution concentration, and Kp is the linear partition co-
efficient.
The linear partition coefficients and Koc values are given in Table
4.20. The Kp values ranged from 1759 for low organic carbon-containing sedi-
ments to 55,697 for high organic carbon-containing sediments. Sorption of di-
benzanthracene was highly correlated with soil organic carbon content but
fairly independent of all other soil properties. Regression of Kp against
soil or sediment organic carbon content gave a Koc value of 1,668,800 (r =
0.783).
47
-------
0.01
0.02 0.03 0.04 0.05 0.06
Cw(ng/ml)
FIGURE 4.10.
REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF
ANTHRACENE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
48
-------
TABLE 4.19. DIBENZ{a3h]ANTHRACENE SORPTION ISOTHERM DATA2
Sample
B2
6
14
20
23
Cwb
(ng/ml)
0.0016
0.0024
0.0034
0.0044
0.0072
0.0011
0.0026
0.0032
0.0043
0.0082
0.0013
0.0030
0.0049
0.0066
0.0100
0.0039
0.0060
0.0096
0.0132
0.0187
0.0015
0.0026
0.0032
0.0053
0.0073
Csc
(ng/g)
19.3
48.4
67.7
96.6
145.0
19.3
48.4
67.7
96.6
144.8
19.2
48.2
67.4
96.2
144.4
19.2
48.3
67.5
96.3
144.7
19.3
48.4
67.8
96.6
145.1
Sample Cw
(ng/ml)
4 0.0010
0.0021
0.0020
0.0031
0.0036
8 0.0145
0.0393
0.0399
0.0505
0.0751
15 0.0009
0.0022
0.0028
0.0039
0.0055
21 0.0004
0.0009
0.0014
0.0017
0.0024
26 0.0006
0.0014
0.0020
0.0025
0.0033
Cs
(ng/g)
19.3
48.4
67.7
96.6
145.2
18.9
47.2
66.6
95.3
143.0
19-3
48.3
67.7
96.5
145.0
19.4
48.5
67.8
96.8
145.3
19.3
48.4
67.8
96.7
145.3
Sample Cw
(ng/ml)
5 0.0018
0.0031
0.0037
0.0053
0.0075
9 0.0073
0.0198
0.0262
0.0374
0.0569
18 0.0015
0.0026
0.0037
0.0051
0.0065
22 0.0006
0.0012
0.0018
0.0025
0.0036
Cs
(ng/g)
19.3
48.4
67.7
96.6
145.0
19.0
47.5
66.6
95.0
142.6
19.2
48.3
67.6
96.4
144.9
19.4
48.4
67.8
96.7
145.2
aValues are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
cCs is the amount sorbed by the soil or sediment sample.
49
-------
TABLE 4.20. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR THE
SORPTION OF DIBENZ[o,ftJANTHRACENE BY SOILS AND SEDIMENTS
% Organic
Sample Kp Koc
B2 1.21 20,461 1.690.971
4 2.07 34,929 1,687,404
5 2.28 18,361 805,292
6 0.72 18,882 2,622,453
8 0.15 1,759 1,172,847
9 0.11 2,506 2,277,875
14 0.48 14,497 3,020,262
15 0.95 25,302 2,663,317
18 0.66 20,192 3,059,425
20 1.30 7,345 565,014
21 1.88 55,697 2,962,603
22 1.67 39,809 2,383,765
23 2.38 19,254 808,991
26 1.48 39,840 2,691,870
50
-------
4.7. 3-METHYLCHOLANTHRENE
3-Methylcholanthrene (20-methylcholanthrene) is an alkyl-substituted
polynuclear aromatic hydrocarbon containing four aromatic rings and one five-
member ed ring. 3-Methylcholanthrene has the second lowest water solubility
of the compounds studied. Its carbon number and molecular length are less
than for dibenzanthracene; hence it is slightly less hydrophobic in nature.
The physical properties of 3-methylcholanthrene are given in Table 4.21.
TABLE 4.21. PHYSICAL PROPERTIES OF 3-METHYLCHOLANTHRENE
Structure
Molecular weight
Melting point (°C)a
Boiling point (°C) at 80 mma
3.
Density
268.34
179-180
280
1.28
aMerck Index. 9th ed.
The octanol-water partition coefficient (Kow) for 3-methylcholanthrene
was determined over a range of aqueous concentrations with radiolabeled
compound using the procedure given in Section 5.2. A Kow value of 2,632,000
was obtained. The water solubility of 3-methylcholanthrene was determined to
be 0.00323 \lg/ml by the procedure outlined in Section 5.3.
Batch equilibrium isotherms were determined using 1 **C-labeled 3-methyl-
cholanthrene obtained from New England Nuclear. Purity of the radiolabeled
compound was verified by thin-layer chromatography. Appropriate amounts of
3-methylcholanthrene were plated from acetone solution (under a stream of Nz
gas) onto the walls of stainless steel centrifuge tubes. These amounts repre-
sented the initial aqueous phase concentrations (4.56 to 48.49 ng/ml) that
would have been present if the compound had been added as aqueous solution.
Exact values for initial aqueous concentrations were determined by pipetting
the same amounts of stock solution into scintillation vials for counting as
were pipetted into the tubes for the isotherm determination. Sorption iso-
therms were determined in triplicate using a 2 g:40 ml soil to solution ratio.
51
-------
1000
0 0.020.04 0.060.08 QIO 0.12 0.14 0.16 0.18 0.200.220.24
Cw(ng/ml)
FIGURE 4.11. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 3-METHYL-
CHOLANTHRENE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
52
-------
TABLE 4.22. 3-METHYLCHOLANTHRENE SORPTION ISOTHERM DATA'
a
Sample Cw^>
(ng/ml)
B2 0.0074
0.0135
0.0187
0.0252
0.0482
6 0.0094
0.0198
0.0288
0.0400
14 0.0040
0.0105
0.0156
0.0184
0.0323
20 0.0092
0.0202
0.0302
0.0401
0.0570
23 0.0064
0.0206
0.0318
0.0395
0.0507
Csc
(ng/g)
90
226
316
452
677
128
320
448
640
128
320
448
642
961
128
320
448
641
961
129
321
449
642
964
Sample Cw
(ng/ml)
4 0.0043
0.0082
0.0107
0.0153
0.0219
8 0.048
0.128
0.292
0.407
15 0.0062
0.0118
0.0189
0.0274
0.0427
21 0.0052
0.0119
0.0174
0.0272
0.0394
26 0.0041
0.0107
0.0121
0.0178
0.0243
Cs
(ng/g)
91
227
317
454
680
125
313
622
936
128
321
449
641
961
129
322
450
643
965
129
322
451
644
966
Sample Cw
(ng/ml)
5 0.0125
0.0237
0.0366
0.0731
0.1204
9 0.053
0.111
0.149
0.242
18 0.0062
0.0142
0.0198
0.0327
22 0.0068
0.0167
0.0208
0.0321
0.0444
Cs
(ng/g)
90
226
316
641
960
125
314
440
625
128
320
449
640
128
321
449
641
963
\7alues are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
°Cs is the amount sorbed by the soil or sediment sample.
53
-------
Isotherm suspensions were shaken in the centrifuge tubes with teflon-covered
lids in a temperature-controlled shaking water bath at 25°C for 24 hours. The
phases were separated by centrifugation.
Initial and final aqueous phase concentrations of Sr^nethylcholanthrene
were determined by liquid scintillation counting. The amount of 3-rmethyl-
cholanthrene sorbed by the soil/sediment phase was calculated from the dif-
ference between initial and final radioactivity levels in the aqueous phase.
Final solution concentrations were corrected for radiolabeled impurities and
degradation products by the procedure outlined in Section 5.4,1.
Representative isotherms are given in Figure 4.11. The isotherms were
linear and gave good fits to the following equation:
Cs = Kp • Cw (4-1)
The sorption data for 3-methylcholanthrene are given in Table 4.22; the
values are averages of triplicate determinations. Linear partition coef-
ficients and Koc values are given in Table 4.23. Regression of Kp against
percent organic carbon gave a Koc value of 1,244,046 (r2 = 0.705).
TABLE 4.23. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR
THE SOPPTION OF 3-METHYLCHOLANTHRENE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
15,140
30,085
8,273
15,820
2,257
2,694
30,627
23,080
20,642
16,231
24,506
20,972
17,127
37,364
Koc
1,251,210
1,453,404
362,845
2,197,250
1,504,538
2,449,190
6,380,703
2,429,456
3,127,521
1.248,534
1,303,532
1,255,821
719,633
2,524,581
54
-------
The sorption of 3-methylcholanthrene and the other three polynuclear
aromatic hydrocarbons studied (pyrene, dimethylbenzanthracene and dibenzan-
thracene) appears to be an example of hydrophobic sorption. For these and
other compounds with very low water solubilities or high octanol-water parti-
tion coefficients, the main driving force in their sorption is related to the
large increase in entropy of the system upon sorption of the organic out of
the aqueous phase. The increase in entropy is due to the destruction of the
highly structured water shell around the solvated organic molecule (14). The
increasing sorption of these compounds with decreasing water solubility is
primarily related to an ever decreasing solute-solvent interaction and possi-
bly to an increasing sorbate-sorbent interaction due to increasing van der
Waals bonding of the compounds to the soil or sediment humic materials.
The highly significant relationship between a compound's octanol-water
partition coefficient and its degree of sorption by soils/sediments when nor-
malized to an organic carbon basis (Koc) is due to the partitioning similari-
ties in both systems. In soil systems and in sediment systems the aqueous
phases are, respectively, the soil solution and the water column plus the
interstitial water, and the organic phases are the humic materials.
If compounds such as pyrene or 3-methylcholanthrene were placed in a
land-fill containing organic materials that were soluble in or miscible with
water (ethanol, acetone, etc.), the sorption characteristics of the compounds
could be greatly altered with subsequent markedly increased mobilities. This
decrease in sorption would be due to a strengthened solute-solvent interaction
upon the addition of the soluble organic.
55
-------
4.8. DIBENZOTHIOPHENE
Heterocyclic polynuclear aromatic compounds such as dibenzothiophene
are added to the environment from a variety of sources and are subject to
environmental concern due to their possible carcinogenic and/or mutagenic
activities ( 37 ). Dibenzothiophene has been identified in used crankcase oil,
on particulates in storm water runoff and on Delaware River sediments (38). In
addition to oil spills and runoff from land-based oil use, heterocyclic sulfur
compounds such as dibenzothiophene are added to the environment in coal gasi-
fication waste waters and in leachates from coal storage areas (2).
The physical properties of dibenzothiophene are given in Table 4.24.
TABLE 4.24. PHYSICAL PROPERTIES OF DIBENZOTHIOPHENE
Structure
Molecular weight3 184.26
Melting point (°C)a 97-100
Boiling point (°C)a 332-333
aAldrich catalog, 1979-80
The octanol-water partition coefficient for dibenzothiophene was
determined over a range of aqueous concentrations using radiolabeled compound
and the procedure given in Section 5.2. A Kow value of 24,000 was obtained.
The water solubility of dibenzothiophene was determined to be 1.47 yg/ml by
the procedure outlined in Section 5.3.
Batch equilibrium sorption isotherms were determined using ^H-labeled
dibenzothiophene that had been tritiated by the method described in Section
5.1.3. The unlabeled dibenzothiophene used in the tritiation procedure was
obtained from Pfaltz and Bauer. Purity was verified using thin-layer chroma-
tography. The sorption isotherms were determined in triplicate using a
4 g:40 ml solid to solution ratio with initial concentrations ranging from
154 to 1230 ng/ml. The isotherms were carried out in stainless steel centri-
fuge tubes with teflon-covered lids in a temperature-controlled shaking water
bath at 25°C for 20 hours. Initial and final concentrations of dibenzothio-
phene in the solution phase were determined by liquid scintillation counting.
The concentration of dibenzothiophene in the soil/sediment phase was determined
by difference.
56
-------
The results of both the sediment-water and the octanol-water partition-
ing experiments could be influenced by degradation of the compound to form
different chemical products or by losses of the compound due to volatilization.
Therefore, in each partitioning experiment with dibenzothiophene, a 3H mass
balance was determined to verify that there was no loss of compound from the
system. High pressure liquid chromatography was used to determine if a
significant quantity of the dibenzothiophene had been degraded. The 3H mass
balance was calculated from the total 3H-labeled material in both the water
and the sediment phases; prior to counting, the 3H-labeled material in the
sediment phase was converted to 3H20 using a Packard Model 306 sample oxidizer.
The recovery of 3H was 99+% in all partitioning experiments, and no evidence
of dibenzothiophene degradation was observed by liquid chromatography.
The sorption of dibenzothiophene by sediment and soils produced
basically linear isotherms which were described by the following equation:
Cs = Kp-Cw (4-1)
where Cs is the amount sorbed in ng/g of soil or sediment, Cw is the equili-
brium solution concentration in ng/ml, and Kp is the linear partition
coefficient. Representative isotherms are shown in Figure 4.12. Average
values for the sorption isotherm data for each soil and sediment are given in
Table 4.25.
The Freundlich adsorption isotherm is represented by the following
equation:
Cs = Kd-Cw1/n (4-3)
where Kd and 1/n are Freundlich constants. Equation 4-3 is equivalent to
equation 4-1 when the exponential Freundlich constant (1/n) is equal to
unity.
The linear partition or sorption constants and r2 values for the fit of
the data to equation 4-1 are given in Table 4.26. The Freundlich constants
(Kd and 1/n) and their corresponding r2 values are also given in Table 4.26.
The 1/n values varied from 0.781 to 1.357 with a mean value of 0.996. The Kd
values were expressed on a molar basis 0-9) and gave values similar to the
linear partition coefficients (Kp) for the respective soils and sediments.
Linear partition coefficients were used instead of Freundlich constants for
subsequent correlation comparisons in order to keep the variation between
samples expressed as one constant instead of two.
The organic carbon content of the sediments or soils was significantly
correlated with Kp at the 1% level of probability, while other factors tested
(e.g., total clay, clay mineralogy, CEC, surface area) were nonsignificant.
When the Kp values were divided by their respective sediment or soil organic
carbon contents, thus putting sorption on a uniform carbon basis, a unique
constant (Koc) for nonpolar compounds was generated.
Koc - Kp/(%OC/100) (2-1)
57
-------
CO
O
12,000-
10,000
8,000
6,000
4,000
2,000
18
8
0 100 200 300 400 500
Cw(ng/ml)
FIGURE 4.12. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF DIBENZOTHIO-
PHENE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
58
-------
TABLE 4.25. DIBENZOTHIOPHENE SORPTION ISOTHERM DATAa
Sample
B2
6
14
20
23
Cwb
(ng/ml)
12.4
24.3
46.6
77.8
92.4
39.2
54.3
93.2
132.2
157.1
25.8
48.0
96.9
147.3
213.4
8.8
18.8
48.7
78.1
117.2
3.0
7.6
15.7
23.9
30.1
Csc
(ng/g)
1413
2832
5683
8447
11376
1145
2532
5218
7903
10729
1279
2595
5181
7752
10166
1450
2887
5663
8444
11128
1508
3000
5993
8986
11999
Sample Cw
(ng/ml)
4 9.6
17.9
31.1
46.3
64.8
8 74.1
148.8
305.4
486.1
634.3
15 7.2
14.5
30.5
48.6
65.7
21 4.0
10.1
20.3
32.5
42.5
26 8.9
18.7
38.6
61.8
87.9
Cs
(ng/g)
1441
2897
5839
8762
11652
797
1588
3096
4365
5957
1466
2930
5846
8739
11643
1498
2974
5947
8900
11875
1449
2888
5764
8607
11421
Sample Cw
(ng/ml)
5 9.4
15.2
36.2
48.6
71.1
9 108.8
211,8
409.5
590.0
754.3
18 18.9
39.2
74.5
120.3
167.6
22 9.0
17.8
32.1
49.3
66.0
Cs
(ng/g)
1444
2923
5788
8739
11589
449
957
2055
3325
4757
1349
2683
5405
8022
10624
1448
2897
5830
8732
11640
aValues are averages of triplicate determinations.
bCw is the equilibrium aqueous concentration.
°Cs is the amount sorbed by the soil or sediment sample.
59
-------
TABLE A.26. LINEAR PARTITION CONSTANTS (Kp) AND THEIR r2 VALUES,
AND MOLAR FREUNDLICH CONSTANTS (Kd and 1/n) AND THEIR r2
VALUES FOR THE SORPTION OF DIBENZOTHIOPHENE
BY SOILS AND SEDIMENTS.
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
Kp
117.5
180.6
167.1
60.8
9.4
5.8
49.7
179.9
65.1
101.4
276.0
176.3
388.6
134.5
r2
0.995
0.989
0.994
0.970
0.996
0.985
0.994
0.996
0.989
0.983
0.983
0.997
0.997
0.989
Koc
9711
8725
7329
8444
6267
5273
10354
18937
9864
7800
14681
10557
16328
9088
Kd
(molar)
118.0
208.7
167.1
67.3
4.1
4.5
49.5
166.2
65.4
82.2
224.9
191.4
304.8
124.7
1/n
(molar)
1.007
1.096
0.993
1.357
0.916
1.204
0.966
0.932
0.957
0.781
0.880
1.057
0.892
0.908
2
0.992
0.974
0.979
0.875
0.991
0.990
0.966
0.993
0.998
0.998
0.996
0.982
0.994
0.996
60
-------
This constant is dependent on the properties of the compound being studied
and independent of soil or sediment properties (11,15,19,39). Koc values
calculated from the linear partition coefficients are given in Table 4.26.
Regression of Kp against soil or sediment organic carbon content gave a Koc
value of 11,230 (r2 = 0.904).
Karickhoff et al. (15) demonstrated a significant relationship between
the octanol-water partition coefficient (Kow) of a compound and its Koc value.
log Koc = 1.00 log Kow - 0.21 (4-5)
where Kow is a measure of compound partitioning between an aqueous phase and
a liquid organic phase, octanol. The Kow value for dibenzothiophene was
determined to be 24,000; this value gave a predicted Koc of 14,798 which was
in good agreement with the Koc (11,230) obtained from the sorption experiments.
Karickhoff et al. (15) found good agreement between measured Koc values and
the Koc values predicted from Kow for a variety of compounds including
benzene, naphthalene, anthracene and pyrene.
The sorption of dibenzothiophene and similar compounds appears to be
an example of hydrophobic or nonpolar sorption (14). The sorption of
dibenzothiophene occurs not because of a strong positive sorbate-sorbent
interaction but rather because of a weak solute-solvent interaction. The
weak solute-solvent interaction is a result of the nonpolar nature of
dibenzothiophene and is manifested in its low water solubility (1.47 yg/ml).
The less polar a compound is, the greater its solubility in octanol, the
lower its solubility in water, and the greater its sorption; hence the
relationship between increasing Kow values and increasing adsorption. This
type of sorption has been referred to as hydrophobic sorption to emphasize
the role of the weak solute-solvent interaction.
61
-------
4.9. ACRIDINE
Nitrogen-heterocyclic compounds deserve special attention because they
make up from 3 to 11 volume percent of the organic contaminants present in
coal tar from the Synthane coal conversion process (2). Acridine (dibenzo-
[&,e]pyridine; 2,3,5,6-dibenzopyridine), 2,2'-biquinoline and 13#-dibenzo-
[o,ilcarbazole were selected as representative compounds for the study of the
sorption of N-heterocyclic compounds by soils and sediments, A brief dis-
cussion of factors affecting the sorption of N-heterocyclics is given in
Section 4.11. The physical properties of acridine are given in Table 4.27.
TABLE 4.27. PHYSICAL PROPERTIES OF ACRIDINE
Structure
Molecular weight 179.22
(Aldrich catalog, 1979-80)
Melting point (°C) 107-110
(Aldrich catalog, 1979-80)
Boiling point- (°C) 346
(Aldrich catalog, 1979-80)
Density 1.005
(CRC Handbook, 1975-76)
The octanol-water partition coefficient (Row) for acridine was deter-
mined over a range of aqueous concentrations using radiolabeled compound and
the procedure described in Section 5,2. A Kow value of 4200 was obtained.
The water solubility was determined to be 38.4 yg/ml by the procedure
outlined in Section 5.3.
Batch equilibrium sorption isotherms were determined using 3H-labeled
acridine that had been tritiated by the method outlined in Section 5.1.3. The
unlabeled acridine used in the tritiation procedure was obtained from Aldrich
Chemical Co. (>99% pure). The tritiated compound was purified by micro-
distillation followed by preparative thin-layer chromatography.
An aqueous stock solution was prepared by evaporating (under a stream
of N£ gas) an appropriate quantity of purified 3H-labeled acridine stock
62
-------
solution onto the lower walls of a glass container, adding ultrapure water and
stirring for 24 hours. To remove any undissolved material, the aqueous stock
solution was filtered through a 0.2y Nuclepore filter. Ultrapure water was
used to dilute the stock solution to the desired concentration levels for
determining the isotherms. Batch equilibrium sorption isotherms were deter-
mined in triplicate on a 1:10 soil to solution ratio with initial acridine
concentrations ranging from 0.29 to 1.74 yg/ml. Isotherm suspensions were
shaken in stainless steel centrifuge tubes with teflon-covered lids in a
temperature-controlled shaking water bath at 25°C for 24 hours. Kinetic
studies showed that sorption equilibrium was attained after approximately nine
hours.
Initial and final aqueous phase concentrations of acridine were deter-
mined by liquid scintillation counting. The concentration of acridine sorbed
by the soil/sediment phase was determined from the difference between the
initial and final radioactivity levels in the aqueous phase. Final solution
concentrations were corrected for radiolabeled impurities and/or degradation
products by the procedure outlined in Section 5.4.1.
Sorption of acridine by soils and sediments resulted in linear sorption
isotherms over the entire concentration range studied. Average values for
individual sorption isotherms are given in Table 4.28. Representative iso-
therms are shown in Figure 4.13.
Initially the data were fit to the Freundlich sorption isotherm
equation:
Cs = Kd-Cw1/n (4-3)
Since 1/n values were very close to unity for all samples, the data were fit
to a modified Freundlich equation where 1/n was forced to be 1.0. A summary
of these data is given in Table 4.29. Regression of Kp against the soil or
sediment organic carbon content produced a Koc value of 12,910 (r = 0.934).
63
-------
TABLE 4.28. ACRIDINE SORPTION ISOTHERM DATA
Sample
B2
6
14
20
23
Cwb
(yg/ml)
0.027
0.065
0.086
0.126
0.156
0.030
0.070
0.110
0.167
0.206
0.034
0.069
0.102
0.164
0.209
0.029
0.062
0.084
0.129
0.147
0.019
0.036
0.062
0.084
0.107
Csc
(yg/g)
4.6
11.9
16.4
23.4
28.1
4.5
11.5
15.6
21.8
26.1
4.6
12.1
16.7
23.3
27.7
4.6
12.0
16.9
23.8
29.0
4.9
12.7
17.2
24.8
29.6
Sample Cw
(yg/ml)
4 0.016
0.036
0.048
0.076
0.091
8 0.088
0.222
0.328
0.470
0.623
15 0.026
0.061
0.094
0.136
0.172
21 0.028
0.064
0.078
0.116
0.142
26 0.020
0.046
0.060
0.108
0.147
Cs
(yg/g)
4.9
12.5
17.6
24.8
30.0
3.5
8.6
11.6
16.5
18.4
4.6
11.8
16.0
22.8
27.2
4.7
11.9
17.1
24.3
29.3
4.8
12.3
17.4
23.9
28.0
Sample Cw
(yg/ml)
5 0.018
0.042
0.065
0.086
0.106
9 0.077
0.208
0.316
0.451
0.536
18 0.041
0.077
0.117
0.220
0.283
22 0.041
0.110
0.154
0.221
0.294
Cs
(yg/g)
4.8
12.3
16.9
24.5
29.4
3.4
8.0
10.3
14.8
18. 1
4.4
12.0
16.5
21.8
25.7
4.4
10.8
15.2
21.7
25.2
Values are averages of triplicate determinations.
bCw is the equilibrium aqueous concentration.
cCs is the amount sorbed by the soil or sediment sample,
64
-------
Cw(/ig/ml)
FIGURE 4.13. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF ACRIDINE BY
SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
65
-------
TABLE 4.29. MODIFIED FREUNDLICH PARTITION CONSTANTS (Kp, 1/n = 1) AND
Koc VALUES FOR SORPTION OF ACRIDINE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
185
334
278
132
33
34
142
165
101
193
207
92
287
213
Koc
15,260
16,160
12,180
18,380
21,720
30,560
29,510
17,350
15,270
14,820
11,020
5,520
12,040
14,370
66
-------
4.10. 2,2'-BIQUINOLINE
The physical properties of 2,2'-biquinoline (2,2'-biquinolyl) are given
in Table 4.30.
TABLE 4.30. PHYSICAL PROPERTIES OF 2,2'-BIQUINOLINE
Structure
Molecular weight 256.31
(Aldrich catalog, 1979-80)
Melting point (°C) 193-196
(Aldrich catalog, 1979-80)
The octanol-water partition coefficient (Kow) for biquinoline was
determined over a range of aqueous concentrations using radiolabeled compound
and the procedure outlined in Section 5.2. A Kow value of 20,200 was obtained.
The water solubility was determined to be 1.02 yg/ml by the procedure described
in Section 5.3.
Batch equilibrium sorption isotherms were determined using 3H-labeled
biquinoline that had been tritiated by the method outlined in Section 5.1.3.
The unlabeled biquinoline used in the tritiation procedure was obtained from
Aldrich Chemical Co. (99% pure). The tritiated compound was purified by
microdistillation followed by preparative thin-layer chromatography. Appro-
priate amounts of biquinoline were plated from acetone solution (under a
stream of N2 gas) onto the walls of stainless steel centrifuge tubes. These
amounts represented the initial aqueous phase concentrations (0.38 to 1.91
yg/ml) that would have been present if the compound had been added as aqueous
solution. Exact values for initial aqueous concentrations were determined by
pipetting the same amounts of stock solution into scintillation vials for
counting as were pipetted into the tubes for the isotherm determinations.
Sorption isotherms were determined in triplicate using a 4 g:40ml soil to
solution ratio. Isotherm suspensions were shaken in the centrifuge tubes with
teflon-covered lids in a temperature-controlled shaking water bath at 25°C for
several hours. Kinetic studies showed that sorption equilibrium was attained
within about one hour.
Initial and final aqueous phase concentrations of biquinoline were
determined by liquid scintillation counting. The concentration of biquinoline
67
-------
0,04 0.08
0.16 0.20 0.24
Cw(/ig/ml)
FIGURE 4.14. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 2,2'-
BIQUINOLINE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
68
-------
TABLE 4.31. 2,2'-BIQUINOLINE SORPTION ISOTHEEM DATA3
Sample
B2
6
14
20
23
Cwb
(yg/ml)
0.034
0.068
0.091
0.110
0.153
0.028
0.042
0.060
0.079
0.099
0.039
0.070
0.103
0.138
0.170
0.039
0.080
0. 116
0.139
0.187
0.017
0.035
0.044
0.061
0.076
Csc
(Pg/g)
3.12
6.25
9.58
13.02
15.95
3.30
6.93
10.46
13.96
17.43
2.92
6.01
9.07
12.09
15.18
3.47
6.89
10.40
14.16
17.44
3.71
7.41
11.32
15.05
18.80
Sample Cw
(yg/ml)
4 0.019
0.038
0.042
0.064
0.058
8 0.061
0.112
0.161
0.204
0.233
15 0.020
0.043
0.062
0.078
0.101
21 0.019
0.037
0.042
0.068
0.082
26 0.025
0.049
0.056
0.073
0.092
Cs
(yg/g)
3.20
6.41
9.96
13.10
16.90
2.65
5.53
8.43
11.48
14.80
2.79
5.53
8.34
11.23
13.95
3.54
7.11
11.05
14.42
18.08
3.36
6.75
10.52
14.07
17.57
Sample Cw
(yg/ml)
5 0.026
0.045
0.079
0.085
0.076
9 0.065
0.115
0.160
0.197
0.236
18 0.031
0.045
0.078
0.096
0.115
22 0.020
0.042
0.059
0.085
0.090
Cs
(yg/g)
3.27
6.68
9.78
13.46
17.49
2.78
5.88
9.08
12.42
15.74
2.46
5.26
7.68
10.38
13.08
3.56
7.09
10.72
14.14
18.07
values are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
CCs is the amount sorbed by the soil or sediment sample.
69
-------
sorbed by the soil/sediment phase was determined from the difference between
the initial and final radioactivity levels in the aqueous phase. Final
solution concentrations were corrected for radiolabeled impurities and/or
degradation products by the procedure outlined in Section 5.4.1.
Sorption of biquinoline, like that of acridine, resulted in linear
sorption isotherms. Representative isotherms are shown in Figure 4.14.
Average values for individual sorption isotherms are given in Table 4.31. As
in the case of acridine, the biquinoline sorption data were fit to a modified
Freundlich equation. A summary of these data is given in Table 4.32. A
regression of Kp against the organic carbon content of the soils and sediments
produced a Koc value of 10,404 (r2 = 0.922). As shown in Table 4.32, samples
8 and 9 had considerably higher calculated Koc values than the other samples
studied. Both of these samples had organic carbon contents less than 0.2%.
The possibility of error in the determination of such low organic carbon
contents is large, and any such error is then magnified in those values (Koc)
based on the low organic carbon content data.
TABLE 4.32. MODIFIED FREUNDLICH PARTITION CONSTANTS (Kp, 1/n = 1) AND Koc
VALUES FOR SORPTION OF 2,2'-BIQUINOLINE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
105
220
164
172
57
61
88
135
106
93
216
181
243
180
Koc
8,710
10,640
7,180
23,850
38,160
55,800
18,310
14,234
16 , 110
7,140
11,500
10,830
10,210
12,180
70
-------
4.11. 135-DIBENZO[a,i]CARBAZOLE
The third N-heterocyclic compound studied was 13ff-dibenzo[a,i]carbazole
(1,2,7,8-dibenzocarbazole). This compound is of interest because it is a
known carcinogen (toxic substances list //H054250). The physical properties of
dibenzocarbazole are given in Table 4.33.
TABLE 4.33. PHYSICAL PROPERTIES OF 13ff-DIBENZOfoilCARBAZOLE
Structure
Molecular weight
(Aldrich catalog, 1979-80)
Melting point (°C)
(Aldrich catalog, 1979-80)
267.33
220-221
The octanol-water partition coefficient (Kow) for dibenzocarbazole was
determined over a range of aqueous concentrations using radiolabeled compound
and the procedure described in Section 5.2. A Kow value of 2,514,000 was
obtained. The water solubility was determined to be 0.0104 ug/ml by the
procedure outlined in Section 5.3.
Batch equilibrium sorption isotherms were determined using 3H-labeled
dibenzocarbazole that had been tritiated by the method given in Section 5.1.3.
The unlabeled dibenzocarbazole used in the tritiation procedure was obtained
from Aldrich Chemical Co. (>99% pure). The tritiated compound was purified by
microdistillation followed by preparative thin-layer chromatography. Appro-
priate amounts of dibenzocarbazole were plated from acetone solution (under a
stream of N2 gas) onto the walls of stainless steel centrifuge tubes. These
amounts represented the initial aqueous phase concentrations (9.02 to 36.08
lag/ml) that would have been present if the compound had been added as aqueous
solution. Exact values for initial aqueous concentrations were determined by
pipetting the same amounts of stock solution into scintillation vials for
counting as were pipetted into the tubes for the isotherm determination.
Sorption isotherms were determined in triplicate using a 2 g:40 ml soil to
solution ratio. Isotherm suspensions were shaken in the centrifuge tubes with
71
-------
800
600
*tn
O
400
200
0.02 0.04 0.06 0.08
0.10
0.12
Cw(ng/ml)
FIGURE 4.15. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 13H-DIBENZO-
[o,-t]CARBAZOLE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
72
-------
TABLE 4.34. 13#-DIBENZO[a,,£]CARBAZOLE SORPTION ISOTHERM DATA3
Sample
B2
6
14
20
23
Cwb
(ng/ml)
0.0071
0.0116
0.0132
0.0176
0.0212
0.0182
0.0219
0.0312
0.0407
0.0545
0.0192
0.0278
0.0497
0.0679
0.0801
0.0138
0.0189
0.0241
0.0350
0.0435
0.0135
0.0213
0.0236
0.0322
0.0539
Csc
(ng/g)
179
251
358
538
717
179
250
358
537
716
177
248
352
529
708
178
249
356
534
713
179
249
357
537
714
Sample Cw
(ng/ml)
4 0.0082
0.0108
0.0166
0.0198
0.0261
8 0.0447
0.0613
0.0888
0.1768
0.2299
15 0.0134
0.0158
0.0267
0.0402
0.0538
21 0.0108
0.0179
0.0188
0.0364
0.0367
26 0.0103
0.0110
0.0171
0.0233
0.0338
Cs
(ng/g)
179
251
359
539
718
174
243
347
514
686
179
251
358
537
717
179
251
359
537
718
179
251
359
538
717
• -^^•^•••••••-a ^ • .^^•^^•^^^^•^^•^^•••M..
Sample Cw
(ng/ml)
5 0.0158
0.0206
0.0264
0.0372
0.0455
9 0.153
0.186
0.343
0.532
0.741
18 0.0114
0.0168
0.0242
0.0361
0.0537
22 0.0102
0.0131
0.0233
0.0267
0.0392
•••••• ^•^••-^^^^•••••a
Cs
(ng/g)
179
250
358
537
717
175
246
348
521
694
179
251
358
537
715
179
251
357
537
716
aValues are averages of triplicate determinations.
bCw is the equilibrium aqueous concentration.
°Cs is the amount sorbed by the soil or sediment sample,
73
-------
teflon-covered lids in a temperature-controlled shaking water bath at 25°C for
24 hours. The phases were separated by centrifugation.
The initial and final aqueous phase concentrations of dibenzocarbazole
were determined by liquid scintillation counting. The concentration of
dibenzocarbazole sorbed by the soil/sediment phase was determined from the
difference between the initial and final radioactivity levels in the aqueous
phase. Final solution concentrations were corrected for radiolabeled impuri-
ties and/or degradation products by the procedure outlined in Section 5.4.1.
Sorption of dibenzocarbazole, like that of the other two N-heterocyclic
compounds, resulted in linear sorption isotherms. Representative isotherms
are shown in Figure 4.15. Average values for individual isotherms are given
in Table 4.34. Modified Freundlich partition constants (Kp, where l/n= 1) were
calculated from individual isotherm values and presented in Table 4.35. A
regression of Kp against soil or sediment organic carbon content produced a
Koc value of 1,055,926 (r2 = 0.830).
TABLE 4.35. MODIFIED FREUNDLICH PARTITION CONSTANTS (Kp, l/n=l) AND Koc
VALUES FOR SORPTION OF 13#-DIBENZO[o, £]CARBAZOLE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
Carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
29,610
25,800
14,640
12,570
3,080
980
8,134
13,480
14,100
15,490
17,040
18,000
13,900
21,620
Koc
2,447,100
1,246,170
642,150
1,745,520
2,056,030
890,610
1,694,550
1,419,110
2,136,570
1,191,150
906,520
1,078,030
583,930
1,460,730
74
-------
The data in Table 4.35 show a 30-fold variation between the lowest and the
highest Kp values; the extremes in Koc values differed by about four-fold.
The dominant soil/sediment physical property accounting for sorption was the
organic carbon content, a finding that was consistent for all three N-hetero-
cyclic compounds studied. Coefficients for correlation of dibenzocarbazole
Kp with selected soil/sediment properties are given in Table 4.36.
TABLE 4.36. CORRELATION (r2) OF 13#-DIBENZO[
-------
4.12. 2-AMINOANTHRACENE
Anthracene-9-carboxylie acid, 2-aminoanthracene and 6-aminochrysene
were chosen as examples of substituted polynuclear aromatic hydrocarbons. The
amine and carboxylie acid functional groups of these compounds greatly modify
the hydrophobic nature of the parent compounds. These compounds were chosen
near the completion of the contract to provide a test of the limitations of
the hydrophobic sorption concept. The factors affecting the sorption of these
compounds are discussed in Section 4.14 following the presentation of the
sorption data for each of the substituted polynuclear aromatic hydrocarbons.
The physical properties of 2-aminoanthracene (2-anthramine) are given in Table
4.37.
TABLE 4.37. PHYSICAL PROPERTIES OF 2-AMINOANTHRACENE
Structure
Molecular weight 193.25
(Aldrich catalog, 1979-80)
Melting point (°C) 238-241
(Aldrich catalog, 1979-80)
The octanol-water partition coefficient (Kow) of 2-aminoanthracene was
determined over a range of aqueous concentration using radiolabeled compound
and the procedure given in Section 5.2. A value of 13,400 was obtained. The
water solubility of 2-aminoanthracene was determined to be 1.30 yg/ml by the
procedure outlined in Section 5.3.
Batch equilibrium isotherms were determined using ^H-labeled 2-amino-
anthracene that had been tritiated by the procedure given in Section 5.1.3.
The unlabeled 2-aminoanthracene used in the tritiation procedure was obtained
from Aldrich Chemical Co. The tritiated compound was purified by microdistil-
lation followed by preparative thin-layer chromatography. Appropriate amounts
of 2-aminoanthracene were plated from acetone solution (under a stream of N2
gas) onto the walls of stainless steel centrifuge tubes. These amounts repre-
sented the initial aqueous phase concentrations (0.64 to 13.65 ng/ml) that
would have been present if the compound had been added as aqueous solution.
Exact values for initial aqueous concentrations were determined by pipetting
the same amounts of stock solution into scintillation vials for counting as
were pipetted into the tubes for the isotherm determination. Sorption iso-
therms were determined in triplicate using a 4 g:40 ml soil to solution ratio.
76
-------
23
o»
O
15
Cw(ng/ml)
FIGURE 4.16. REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 2-AMINO-
ANTHRACENE BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
77
-------
TABLE 4.38. 2-AM1NOANTHRACENE SOKPTION ISOTHERM DATA'
Sample
B2
6
14
20
23
Cwb
(ng/ml)
0.031
0.048
0.107
0.185
0.383
0.152
0.107
0.199
0.236
0.409
0.064
0.072
0.210
0.398
0.867
0.020
0.069
0.102
0.146
0.247
0.012
0.031
0.051
0.088
0.131
Csc
(ng/g)
5.8
12.2
32.7
67.2
128.6
3.6
11.2
31.2
66.6
128.8
5.4
12.1
31.7
64.9
123.1
5.8
11.0
31.7
66.5
128.8
6.0
12.2
33.3
68.3
132.4
Sample Cw
(ng/ml)
4 0.025
0.016
0.121
0.194
0.373
8 0.089
0.143
0.375
0.908
1.253
15 0.016
0.030
0.076
0.169
0.313
21 0.023
0.058
0.077
0.123
0.230
26 0.015
0.024
0.069
0.101
0.177
Cs
(ng/g)
5.9
12.9
32.5
67.2
129.0
5.0
11.0
29.1
57.0
117.1
6.0
12.4
33.0
66.7
128.4
5.8
11.7
33.0
68.0
130.7
6.0
12.5
33.0
68.3
131.6
Sample Cw
(ng/ml)
5 0.024
0.037
0.128
0.234
0.394
9 0.093
0.269
0.343
0.713
0.963
18 0.024
0.047
0.092
0.120
0.470
22 0.031
0.016
0.071
0.158
0.241
Cs
(ng/g)
5.9
12.4
32.0
65.9
127.7
5.0
9.0
29.6
60.1
121.6
5.9
12.1
32.9
68.4
126.0
5.8
12.9
33.4
67.9
131.6
values are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
£
Cs is the amount sorbed by the soil or sediment sample.
78
-------
Isotherm suspensions were shaken in the centrifuge tubes with teflon-covered
lids in a temperature-controlled shaking water bath at 25°C for 24 hours.
Initial and final aqueous phase concentrations of 2-aminoanthracene
were determined by liquid scintillation counting. The concentration of 2-
aminoanthracene sorbed by the soil/sediment phase was determined from the dif-
ference between the initial and final radioactivity levels in the aqueous
phase. Final solution concentrations were corrected for radiolabeled impuri-
ties and/or degradation products by the procedure described in Section 5.4.1.
Representative isotherms are given in Figure 4.16. The isotherms were
linear and gave good fits to the following equation:
Cs = Kp-Cw (4-1)
The sorption data for 2-aminoanthracene are given in Table 4.38; the values
are averages of three determinations. Linear partition coefficients and Koc
values are given in Table 4.39. Regression of Kp against percent organic
carbon in the soils or sediments gave a Koc value of 28,129 (r2 = 0.871).
TABLE 4.39. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR
THE SORPTION OF 2-AMINOANTHRACENE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
^"^^^^— ^^^^^^^— *^^-^— *^— »^»— »»*^p^»—
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
~~~*t~~**^—^^~*mmim~~*~~~~mmmm*mimm*mmmmmmmiim
Kp
321.6
329.2
304.1
259.5
79.0
103.7
145.1
391.9
283.0
458.7
531.9
502.1
875.2
688.7
•'^^^^^••^^^^^•^•^^•^•^••^^^^••^••^•^^fc^.^^^^^,^^,,,,1,1 !•
Koc
26,580
15,904
13,336
36,039
52,659
94,276
30,225
41,248
42,878
35,287
28,292
30,069
36,772
46,537
79
-------
4.13. 6-AMINOCHRYSENE
6-Aminochrysene (6-chrysenamine) was chosen of one representative of
substituted polynuclear aromatic hydrocarbons containing functional groups
that could greatly modify their hydrophobic nature. The physical properties
of 6-aminochrysene are given in Table 4.40.
TABLE 4.40. PHYSICAL PROPERTIES OF 6-AMINOCHRYSENE
Structure
NH2
Molecular weight
(Aldrich catalog, 1979-80)
Melting point (°C)
(Aldrich catalog, 1979-80)
243.31
209-211.5
The octanol-water partition coefficient (Kow) of 6-aminochrysene was
determined over a range of aqueous concentrations using radiolabeled compound
and the procedure outlined in Section 5.2. A value of 96,600 was obtained.
The water solubility of 6-aminochrysene was determined to be 0.155 yg/ml by
the procedure described in Section 5.3.
Batch equilibrium isotherms were run using 3H—labeled 6-aminochrysene
that had been tritiated by the procedure given in Section 5.1.3. The un-
labeldd aminochrysene used in the tritiation procedure was obtained from
Aldrich Chemical Co. The tritiated compound was purified by microdistillation
followed by preparative thin-layer chromatography. Appropriate amounts of
aminochrysene were plated from acetone solution (under a stream of Na gas)
onto the walls of stainless steel centrifuge tubes. These amounts represented
the initial aqueous phase concentrations (1.81 to 36.3 ng/ml) that would have
been present if the compound had been added as aqueous solution. Exact values
for initial aqueous concentrations were determined by pipetting the same
amounts of stock solution into scintillation vials for counting as were pi-
petted into the tubes for the isotherm determination. Sorption isotherms were
determined in triplicate using a 4 g:40 ml solid to solution ratio. Isotherm
suspensions were shaken in the centrifuge tubes with teflon-covered lids in a
80
-------
400
20
O.I 0.2 0.3
Cw(ng/ml)
0.4
0.5
FIGURE 4.17.
REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF 6-AMINOCHRYSENE
BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
81
-------
TABLE 4.41. 6-AMINOCHRYSENE SORPTION ISOTHERM DATAS
Sample Cw
(ng/ml)
B2 0.015
0.029
0.055
0.062
0.193
6 0.040
0.039
0.083
0.144
0.323
14 0.059
0.075
0.152
0.193
0.312
20 0.033
0.076
0.103
0.187
0.394
23 0.011
0.031
0.046
0.079
Csc
(ng/g)
17.6
35.3
89.2
177.6
356.6
16.6
35.0
88.2
176.2
352.2
16.1
33.8
85.9
174.6
352.6
17.0
33.8
87.6
174.8
349.9
17.7
35.3
179.4
360.4
Sample Cw
(ng/ml)
4 0.008
0.025
0.032
0.064
0.104
8 0.051
0.073
0.150
0.296
0.579
15 0.020
0.055
0.072
0.124
0.268
21 0.026
0.030
0.041
0.069
0.120
26 0.035
0.057
0.066
0.120
0.169
Cs
(ng/g)
17.8
35.5
89.9
178.9
359.5
16.4
33.9
86.0
171.1
343.7
17.4
34.5
88.6
176.9
354.1
17.2
35.3
89.6
178.7
359.0
16.9
34.4
88.8
177,0
357.4
Sample Cw
(ng/ml)
5 0.017
0.012
0.032
0.038
0.084
9 0.049
0.080
0.137
0.274
0.466
18 0.019
0.030
0.063
0.125
0.244
22 0.026
0.082
0.104
0.111
0.191
Cs
(ng/g)
17.5
35.9
89.9
179.7
360.2
16.5
33.6
86.4
171.9
347.4
17.5
35.3
88.9
176.8
354.9
17.2
33.6
87.5
177.3
356.6
Values are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
c
Cs is the amount sorbed by the soil or sediment sample.
82
-------
temperature-controlled shaking water bath at 25°C for 20 hours. After equili-
bration the phases were separated by centrifugation.
Initial and final aqueous phase concentrations of 6-aminochrysene were
determined by liquid scintillation counting. The concentration of 6-amino-
chrysene sorbed by the soil/sediment phase was determined from the difference
between the initial and final radioactivity levels in the aqueous phase.
Final solution concentrations were corrected for radiolabeled impurities and
degradation products by the procedure outlined in Section 5.4.1,
Representative isotherms are given in Figure 4.17. The isotherms were
linear and gave good fits to the linear partition equation (4-1). The sorp-
tion data for 6-aminochrysene are given in Table 4.41; the values are averages
of three determinations. Linear partition coefficients and Koc values are
given in Table 4.42. Regression of Kp against soil or sediment organic carbon
content gave a Koc value of 143,355 (r2 = 0.944).
TABLE 4.42. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR
THE SORPTION OF 6-AMINOCHRYSENE BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
1,736
3,116
3,972
1,079
573
686
924
1,292
1,424
872
2,616
1,459
3,923
1,689
Koc
143,427
150,519
174,232
149,817
382,185
624,022
192,553
136,025
215,835
67,070
139,149
87,363
164,844
114,108
83
-------
4.14. ANTHRACENE-9-CARBOXYLIC ACID
Anthracene-9-carboxylic acid was the third compound chosen to represent
the substituted polynuclear aromatic hydrocarbons. Anthracene-9-carboxylic
acid forms an anion upon dissociation of the carboxyl group while 2-amino-
anthracene and 6-aminochrysene form cations upon protonation of the amine
groups. The physical properties of anthracene-9-carboxylie acid are given in
Table 4.43.
TABLE 4.43. PHYSICAL PROPERTIES OF ANTHRACENE-9-CARBOXYLIC ACID
COOH
sO^S
Structure
Molecular weight 222.24
(Aldrich catalog, 1979-80)
Melting point (°C) 214 (decomposes)
(Aldrich catalog, 1979-80)
The octanol-water partition coefficient (Kow) of anthracene-9-carboxy-
lic acid was determined over a range of aqueous concentrations using radio-
labeled compound and the procedure outlined in Section 5.2. A value of 1300
was obtained. The water solubility of anthracene-9-carboxylic acid was
determined to be 85.0 yg/ml by the procedure described in Section 5.3.
Batch equilibrium isotherms were run using 3H-labeled anthracene-9-
carboxylic acid that had been tritiated by the procedure outlined in Section
5.1.3. The unlabeled anthracene-9-carboxylic acid used in the tritiation pro-
cedure was obtained from Aldrich Chemical Co. The tritiated compound was
purified by microdistillation followed by preparative thin-layer chromatog-
raphy. Appropriate amounts of anthracene-9-carboxylic acid were plated from
acetone solution (under a stream of N2 gas) onto the walls of stainless steel
centrifuge tubes. These amounts represented the initial aqueous concentra-
tions (3.85 to 79.94 ng/ml) that would have been present if the compound had
been added as aqueous solution. Exact values for initial aqueous concentra-
tions were determined by pipetting the same amounts of stock solution into
scintillation vials for counting as were pipetted into the tubes for the iso-
therm determination. Sorption isotherms were determined in triplicate using
a 4 g:40 ml solid to solution ratio. Isotherm suspensions were shaken in the
centrifuge tubes with teflon-covered lids in a temperature-controlled shaking
water bath at 25°C for 20 hours. The phases were separated by centrifugation.
84
-------
20
0.01
0.02
0.03
0.04
Cw(yu.g/ml)
FIGURE 4.18.
REPRESENTATIVE ISOTHERMS FOR THE SORPTION OF ANTHRACENE-9-
CARBOXYLIC ACID BY SOILS AND SEDIMENTS
Numbers refer to soil or sediment samples.
85
-------
TABLE 4.44. ANTHRACENE-9-CARBOXYLIC ACID SORPTION ISOTHERM DATA
Sample Cw
(yg/ml)
B2 0.0014
0.0030
0.0096
0.0163
0.0366
6 0.0006
0.0030
0.0089
0.0154
0.0347
14 0.0017
0.0032
0.0087
0.0146
0.0304
20 0.0028
0.0066
0.0144
0.0257
23 0.0018
0.0030
0.0076
0.0148
0.0303
Cwc
(yg/g)
0.0144
0.0289
0.0409
0.1362
0.1750
0.0282
0.0261
0.0429
0.1359
0.1717
0.0116
0.0292
0.0625
0.1776
0.3070
0.0328
0.0934
0.1721
0.3693
0.0092
0.0305
0.0787
0.1700
0.2990
Sample Cw
(yg/ml)
4 0.0016
0.0035
0.0095
0.0153
0.0385
8 0.0009
0.0037
0.0094
0.0195
0.0380
15 0.0020
0.0040
0.0116
0.0235
0.0409
21 0.0008
0.0032
0.0086
0.0159
0.0342
26 0.0003
0.0017
0.0065
0.0139
0.0419
Cw
(yg/g)
0.0128
0.0233
0.0516
0.1684
0.1804
0.0204
0.0093
0.0221
0.0385
0.0680
0.0064
0.0146
0.0129
0.0286
0.1280
0.0245
0.0244
0.0559
0.1402
0.2117
0.0354
0.0581
0.1203
0.2352
0.2601
Sample Cw
(yg/ml)
5 0.0014
0.0032
0.0090
0.0159
0.0299
9 0.0098
0.0198
0.0378
18 0.0020
0.0037
0.0094
0.0186
0.0436
22 0.0012
0.0028
0.0090
0.0185
0.0368
Cs
(yg/g)
0.0120
0.0207
0.0379
0.1233
0.2525
0.0247
0.0555
0.1115
0.0051
0.0162
0.0436
0.0987
0.0591
0.0185
0.0333
0.0576
0.1142
0.2004
Values are averages of triplicate determinations.
Cw is the equilibrium aqueous concentration.
^
"Cs is the amount sorbed by the soil or sediment sample.
86
-------
Initial and final aqueous concentrations of anthracene-9-carboxylic
acid were determined by liquid scintillation counting. The concentration of
anthracene-9-carboxylic acid sorbed by the soil/sediment phase was determined
from the difference between the initial and final radioactivity levels in the
aqueous phase. Final solution concentrations were corrected for radiolabeled
impurities and/or degradation products by the procedure described in Section
5.4.1.
Representative isotherms are given in Figure 4.18. The isotherms were
linear and gave good fits to the linear partition equation (4-1). Sorption
data for anthracene-9-carboxylic acid are given in Table 4.44; the values are
averages of three determinations. Linear partition coefficients and Koc
values are given in Table 4.45. Regression of Kp against soil or sediment
organic carbon content gave a Koc value of 422 (r2 = 0.751).
TABLE 4.45. LINEAR PARTITION COEFFICIENTS (Kp) AND Koc VALUES FOR
THE SORPTION OF ANTHRACENE-9-CARBOXYLIC ACID BY SOILS AND SEDIMENTS
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
% Organic
carbon
1.21
2.07
2.28
0.72
0.15
0.11
0.48
0,95
0.66
1.30
1.88
1.67
2.38
1.48
Kp
5.27
5.49
7.96
5.47
1.84
2.82
10.03
2,66
1.78
13.27
6,45
5.59
9.88
7.50
Koc
436
265
349
760
1,227
2,564
2,090
280
270
1,021
343
335
415
507
The addition of hydrophilic functional groups to a hydrophobic compound
will greatly increase the water solubility of the compound. Anthracene has a
water solubility of 0.073 yg/ml (15) while 2-aminoanthracene and anthracene-9-
87
-------
carboxylic acid have respective water solubilities of 1.30 and 85.0 yg/ml.
The addition of a hydrophobic group such as a methyl group will decrease water
solubility (15).
The hydrophilic functional group can affect sorption in different ways.
If the functional group is involved in a specific reaction (e.g., cation ex-
change) with the soil or sediment, then the concept of the solute-solvent
interaction dictating the degree of sorption will no longer be valid, and
sorption will be much greater than predicted from the water solubility or Kow
value. The sorption of benzidine is such an example. If the functional group
does not enter into a specific reaction with the soil or sediment, then its
effect will only be manifested in the solute-solvent interaction. In this
case sorption will still be highly correlated with the compound's water solu-
bility and/or Kow value. Anthracene-9-carboxylic acid, 2-aminoanthracene and
6 aminochrysene are examples of the latter case.
88
-------
SECTION 5
EXPERIMENTAL METHODS
5.1. PREPARATION AND TRITIATION OF COMPOUNDS
All of the compounds used in the present study were available com-
mercially in relatively pure form. Those exhibiting a level of purity below
95% were successfully purified by the procedure outlined below. Because many
of the compounds are light-sensitive, the various manipulative and analytical
procedures were carried out in the presence of either darkness or subdued
light. Furthermore, because many of the compounds are subject to atmospheric
oxidation, all containers (e.g., tubes, flasks, developing tanks) were
flooded with N2 to maintain an anaerobic atmosphere.
5.1.1. Chromatographic Analyses
5.1.1.1. Thin-Layer Chromatography
The most frequently used procedure for identifying suspected compounds
and determining their degree of purity in the present investigation was thin-
layer chromatography (TLC). The procedure is rapid, relatively simple,
reproducible, and generally reliable.
The TLC developing tanks containing appropriate solvent systems (see
Table 5.1) were flooded with N£ and allowed to equilibrate at room tempera-
ture for about one hour. Commercially available 20x20-cm and 5x20-cm glass
plates coated with 0.25 or 0.5-mm-thick layers of silica gel G (non-fluores-
cent) were activated in a 100°C oven for one hour and stored in a desiccator
box until used. A vertical line was scribed with a dissecting needle about
one-eighth inch in from the side edges of each plate so that solvent migra-
tion on the bulk of the plate would not be affected by the change in
capillarity at the edge of the plate where the coating ceased. A horizontal
solvent front line 15 cm above the origin (which was marked lightly with a
pencil 1.5 cm from the bottom) and vertical lines demarking lanes were
similarly scribed. A 5x20-cm plate accommodated up to three lanes easily,
and a 20x20-cm plate a dozen or more lanes.
In most cases, approximately 5 yg of compound in an appropriate sol-
vent (e.g., ether) were spotted at the origin in a given lane. After
development of the chromatogram in the appropriate solvent system (see Table
5.1), the plate was air-dried or gently blown dry in a stream of N2.
Examination of the plate under short-wave ultraviolet (UV) light revealed
fluorescent spots against a dark (UV-absorbing) background. (N.B. All
compounds used in the present study fluoresced under UV light.) While the
89
-------
TABLE 5.1. TYPICAL Rf VALUES FOR 14 ENERGY-RELATED COMPOUNDS
IN SELECTED THIN-LAYER CHROMATOGRAPHIC SOLVENT SYSTEMS
Compound
Solvent System5
Approximate
Rf Value
Pyrene
7,12-Dimethylbenz [a]anthracene
Dibenz [at ftjanthracene
3-Methylcholanthrene
Dibenzothiophene
Acridine
2,2'-Biquinoline
13ff-Dibenzo [o,£]carbazole
Acetophenone
1-Naphthol
Benzidine
2-Aminoanthracene
6-Aminochrysene
Anthracene-9-carboxylic acid
n-Hexane : diethyl ether (95:5) 0.73
n-Hexane : diethyl ether (100:3) 0.64
n-Hexane : diethyl ether (100:3) 0.70
n-Hexane : diethyl ether (100:3) 0.61
n-Hexane : diethyl ether (100:3) 0.75
Benzene : methanol (95:5) 0.73
Methylene chloride : methanol (98:2) 0.73
n-Hexane : diethyl ether (50:50) 0.70
Benzene : acetone (95:5) 0.69
Benzene : methanol (9:1) 0.57
Benzene : methanol (7:3) 0.70
Benzene : methanol : HAc (9:1:0.05) 0.67
Benzene : methanol (95:5) 0.71
Benzene : methanol : HAc (7:3:0.05) 0.56
aAll solvents were measured on a volume basis; HAc = glacial acetic acid.
-------
plate was still under the UV light, outlines of spots were marked with a
pencil. The Rf value of a compound was calculated as the distance (in cm)
from the origin to the center of the spot divided by the distance from the
origin to the solvent front. In the indicated solvent systems, the Rf values
listed in Table 5.1 were expected.
5.1.1.2. Gas-Liquid Chromatography
The second most frequently used procedure for identifying suspected
compounds, measuring the degree of purity of the compounds, and quantitating
compounds in the present investigation was gas-liquid chromatography (GLC).
Like TLC, this procedure is rapid, relatively uncomplicated, reproducible and
generally reliable.
A Varian Aerograph Series 1860 Gas Chromatograph with flame ionization
detector was utilized for determinations involving a 12-foot OV-17 column.
The hydrogen flow rate for this instrument was maintained at 32 ml/min, the
air flow rate at 270 ml/min, and the nitrogen (carrier gas) flow rate at
25 ml/min. The injection port temperature was 225°C, and the detector
temperature 300°C. Column temperatures were either maintained isothermally
or programmed at a rate of 8° per minute, depending upon the compound.
A Varian Aerograph Series 2700 Gas Chromatograph with flame ionization
detector was used when a Carbowax column or a 6-foot OV-17 column was pre-
ferred. Both chromatographs were operated in conjunction with a Hewlett-
Packard Model 3380A Recording Integrator. The hydrogen flow rate for the
Series 2700 instrument was maintained at 25 ml/min, the air flow rate at
230 ml/min, and the nitrogen flow rate at 25 ml/min. The injection port
temperature was 175°C, and the detector temperature 310°C. The temperatures
of both columns were maintained isothermally.
Silanized six and 12-foot glass columns were packed with 3% OV-17 on
80/100-mesh Supelcoport (Supelco, Inc., Beliefonte, PA). These two columns
were used for the detection and quantitanion of most of the compounds in the
present study. Under the indicated conditions, the retention times presented
in Table 5.2 were expected.
A silanized 6-foot stainless steel column was packed with 0.2%
Carbowax 1500 on 60/80-mesh Carbopack C (Supelco). This column was used
primarily for the detection and quantitation of acetophenone and small
quantities of a-naphthol in water samples. Under the indicated conditions,
the retention times of a-naphthol and acetophenone were -v24 and ^30 minutes,
respectively. Because the retention times were rather long, triplicate
injections could be made at 5-minute intervals, thus minimizing the time
necessary for replicated results.
5.1.2. Purity and Purification Procedures
5.1.2.1. Determination of Specific Activity and Radiochemical Purity
All radiolabeled compound preparations purchased from commercial
sources or tritiated in the laboratory were analyzed to determine the exact
91
-------
TABLE 5.2. TYPICAL GAS-LIQUID CHROMATOGRAPHIC CONDITIONS AND RETENTION TIMES
FOR 14 ENERGY-RELATED COMPOUNDS
VO
Compound
Pyrene
7, 12-DimethylbenzJo] anthracene
Dibenzjo, hj anthracene
3-Methylcholanthrene
Dibenzothiophene
Acridine
2,2'-Biquinoline
13ff-Dibenzo{a, i]carbazole
Acetophenone
1-Naphthol
Benzidine
2-Aminoanthracene
6-Aminochrysene
Anthracene-9-carboxylic acid
Column3
OV-17 (12')
OV-17 (12')
OV-17 (6')
OV-17 (12* )
OV-17 (12* )
OV-17 (6')
OV-17 (6')
OV-17 (12 ')
Carbowax (61)
,OV-17 (12 ')
Carbowax (61)
OV-17 (61)
OV-17 (6')
OV-17 (6f)
OV-17 (61)
Column
Temperature
Operation
Isothermal
Programmed
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Isothermal
Column
Temperature
185
150-280
275
300
170
130
210
300
190
140
190
185
185
260
140
Approx.
Retention
Time
(min)
6.5
16
2.7
10
4.2
3.1
5.4
4.0
30
3.7
24
3.6
3.1
2.5
3.0
aOV-17 = 3% OV-17 on 80/100-mesh Supelcoport; Carbowax = 0.2% Carbowax 1500 on 60/80-mesh
Carbopack C.
All program rates were 8° per minute.
-------
amount of radioactivity (in disintegrations per minute, dpm) and the total
weight of compound contained therein. In addition, each compound was analyzed
for radiochemical purity by means of TLC (Table 5.3).
The radiolabeled compound was dissolved or diluted in an appropriate
solvent (e.g., acetone) in a 15-ml screw-capped centrifuge tube at the rate
of 50 yCi/5 ml. In order to minimize evaporation and maximize compound
stability, this stock solution was stored under N2 at 0°C between uses.
Triplicate one-yl samples of the stock solution were subjected to
liquid scintillation counting in order to determine the exact number of dpm
present in the solution. In the case of radiolabeled compounds purchased
from commercial sources, the total mg of compound received was calculated
from the specific activity provided by the source and the dpm determined
above. In the case of compounds tritiated in the laboratory, the total mg
were determined by GLC using pure unlabeled compound as the standard. The
weight was verified gravimetrically by evaporating a known quantity of solu-
tion to dryness in a tared tube under a stream of N2 and reweighing the tube
and contents in order to obtain the net weight. From the dpm and the weight
values, the specific activity of the tritiated compound was calculated.
A TLC tank containing the appropriate solvent system (see Table 5.1)
was flooded with N2 and allowed to equilibrate at room temperature for about
one hour. The stock solution was spotted at the rate of vLO,000 dpm/spot
along with a small amount of unlabeled standard solution on a 5x20-cm 0.25-
mm - thick silica gel G plate. The plate was developed to the solvent front
and then air-dried or gently blown dry in a stream of N2. The location of
the unlabeled standard was visualized under UV light and recorded. One-cm
segments from the solvent front to the bottom of the plate were scraped into
vials of Aquasol (New England Nuclear, Boston, MA) for liquid scintillation
counting.
The quantity of radioactivity in the segments corresponding to the
unlabeled standard was calculated as a percentage of the total radioactivity
in the sample lane. If the compound was >95% pure, no further purification
was necessary. If the purity was <95%, the compound was subjected to the
purification procedure outlined below.
5.1.2.2. Purification of Compounds
The following modifications of the analytical thin-layer chromatography
procedure for determining radiochemical purity (described above) were suf-
ficient to convert it into a preparative procedure for purification of the
compounds used in this study. The.compound in question was banded (without
the presence of unlabeled standard) at the rate of about 15 uCi per 20x20-cm
plate for radiolabeled compounds or 100 mg per 20x20-cm plate for unlabeled
compounds on a 0.5-mm-thick silica gel G plate. After development of the
chromatogram, the fluorescent band with the appropriate Rf value (see Table
5.1) was stipple-outlined by means of a dissecting needle. (This band was
always the major band on the plate.) The band was immediately scraped into a
50-ml screw-capped centrifuge tube, and the compound eluted from the silica
gel with three 20-ml volumes of appropriate solvent (e.g., acetone) under N2.
93
-------
TABLE 5.3. RADIOCHEMICAL PURITY INFORMATION FOR 14 ENERGY-RELATED COMPOUNDS USED IN THIS STUDY
10
Compound
Pyrene
7 , 1 2-D ime thy Ib enz-
[a] anthracene
Dibenz [a, ft]anthracene
3-Methylcholanthrene
Dibenzothiophene
Acridine
2,2'-Biquinoline
13#-Dibenzo-
Acetophenone
1-Naphthol
Benzidine
2-Aminoanthracene
6-Aminochrysene
Anthracene-
9-carboxylic acid
-
Label
Position
3H(G)
7,12-di-
methyl-14C
3H(G)
6-14C
3H(G)
3H(G)
3H(G)
3H(G)
7-14C
1-14C
14C(U)
3H(G)
3H(G)
3H(G)
ft
Source
UI
NEN
NEN
NEN
UI
UI
UI
UI
ICN
ICN
NEN
UI
UI
UI
Purity
Specified
by Source
_
98
96
97
-
-
-
-
>98
>98
98
-
-
—
Purity
Det'd in
This Lab
99.6
80.6
89.3
94.2
88.6
81.3
80.5
88.7
90.7
97.1
98.3
87.0
91.2
84.2
Purity
after
Purif 'n
FPUb
99.2
97.7
97.1
98.2
97.1
97.0
99.5
98.1
FPU
FPU
97.1
99.4
97.4
Specific
Activity
(mCi/mmol)
300
114.65
35.14°
60.2
9.76
0.111, 0.136d
0.0868
185
5.8
10.0
25.7
24.9
55.2
0.926
aMEN = New England Nuclear; ICN
during present investigation.
FPU = further purification unnecessary.
cCi/mmol.
batches of acridine were tritiated.
ICN Chemical and Radioisotope Div.; UI = tritiation carried out
-------
The eluates were combined and concentrated to a small volume under a stream
of N2. Any residual silica gel present in the concentrated eluate was
removed by centrifugation. The eluate was then subjected to analytical TLC
to check for purity. All compounds purified in this manner showed only a
single spot on TLC and a single peak on GLC; all radiolabeled compounds were
>95% pure.
5.1.3. Tritiation
Five of the compounds selected for investigation were available
commerciallly in 14C-labeled form and one in 3H-labeled form. The remaining
compounds were not available in radiochemical form except by custom synthesis
which is expensive. Tritiation of the latter compounds by a modification of
the procedures of Hilton and O'Brien (40) and Lu et al. (41) proved to be an
effective and relatively inexpensive means of radiolabeling these compounds.
Five millimoles (0.56 g) of P20s were placed in a 5-ml round-bottom
flask that was fitted with a desiccating U-tube and chilled in a slurry of
acetone-dry ice in a small crystallizing dish. By means of a disposable
syringe and needle, 12 millimoles (0.21 ml) of 3H2° were allowed to run down
the side of the flask where the water froze. The flask was removed from the
slurry bath so that the water gradually melted and reacted with the T?2°5 to
form tritiated phosphoric acid. When the reaction was complete, the reaction
mixture was bubbled with BF3 gas for about 10 minutes. A magnetic stirring
bar was added to the flask, followed by an appropriate quantity of tritiatable
compound (50-500 mg) dissolved in a small quantity of a suitable organic
solvent (about one ml). Characteristics of a suitable organic solvent include
immiscibility with water, a minimum number of exchangeable hydrogens, and the
capacity to dissolve the tritiatable compound at a level of 50-500 mg/ml.
The reaction mixture was stirred overnight at room temperature with the drying
tube in place; the hydrogen-tritium exchange occurred during this period.
The reaction mixture was transferred to a 200-ml round-bottom flask;
50 ml of water and 50 ml of solvent, part of which had been used to rinse the
reaction vessel, were added along with a magnetic stirring bar. The flask
was loosely stoppered (small piece of aluminum foil inserted between stopper
and flask) and the mixture stirred overnight at room temperature. The flask
contents were transferred to a 500-ml separatory funnel; the aqueous phase
was removed and saved. The solvent phase was extracted with two 100-ml vol-
umes of water-solvent (2:1, v/v); the solvent phases were transferred to a
500-ml round-bottom flask. The combined aqueous phases were extracted with
about 150 ml of solvent, the aqueous phase discarded, and the solvent phase
added to the round-bottom flask. Sufficient methanol was added to provide a
total volume of about 350 ml.
The flask was placed in a heating mantle over a magnetic stirrer, a
stirring bar added, and a microdistillation apparatus connected. Consecutive
25-ml fractions were collected and monitored for radioactivity. In cases
where the initial solvent was cyclohexane, the distillate was biphasic; both
phases were monitored for radioactivity. Distillation was continued until
the radioactivity in the distillate reached a low plateau, at which point the
initial solvent had been distilled off completely. During distillation, for
95
-------
every 50 ml of distillate collected, 50 ml of methanol were added to the
distillation flask. After the low radioactivity plateau was reached, the
microdistillation apparatus was disconnected, a few grams of anhydrous
were added to the distillation flask, and the contents were allowed to stand
for a few hours at room temperature to dry off residual water.
The liquid phase was transferred to a fresh 500-ml flask, followed by
several rinses of the previous flask, and evaporated to near-dryness on a
rotary evaporator. The flask contents were transferred, with rinses, to a
15-ml screw-capped centrifuge tube. The solution was concentrated to a
reasonable volume (e.g., 10 ml) under a stream of N£. Radiochemical purity
of each tritiated compound was determined by the TLC procedure outlined
earlier in this section. If not ^99% pure, the compound was purified by the
preparative TLC procedure described earlier in this section. Aliquots of a
solution of the pure compound were subjected both to liquid scintillation
counting in order to determine radioactive content and to GLC along with
standard solutions to determine concentration. A known volume of the solution
was evaporated to dryness in a tared tube under a stream of N2 and the weight
of the compound per given volume of solution verified. The specific activity
of the tritiated compound was calculated.
For all compounds tritiated during the present study, tritiation
involved the exchangeable hydrogens on the aromatic rings. The rather strin-
gent conditions inherent in the tritiation procedure were sufficient to
remove any label from the substituent groups of 6-aminochrysene, 2-aminoanth-
racene and anthracene-9-carboxylic acid. Nevertheless, in order to verify
that no residual tritium remained on the substituent groups, the following
procedure was utilized.
Two small aliquots (e.g., 0.2 ml) of a methanolic solution of each
tritiated amino-substituted compound were diluted to 5 ml with water (pH 6).
One solution was adjusted to pH 10-11 with IN NaOH in order to ionize the
substituent group, mixed well, allowed to stand for a few minutes, and then
readjusted to pH 6 with IN HC1. Dilution of the carboxylic acid-substituted
compound in water (at pH 6) was sufficient to ionize the substituent group,
and therefore only a single solution of this compound was prepared.
The solutions were extracted three times with equal volumes of methy-
lene chloride. The volume of the extracted aqueous phases remained at 5 ml;
the volumes of the extracts were recorded. Both the aqueous phases and the
extracts were sampled in triplicate (1.0 ml for the former, 0.2 ml for the
latter) for liquid scintillation counting. The percent radioactivity
remaining in the aqueous phase after extraction was the same for both solu-
tions (pH-adjusted and unadjusted) and amounted to less than 0.2% of the
total radioactivity present in the extract and the extracted aqueous phase.
If the substituent groups of the three compounds had been tritiated, the pH-
adjusted aqueous phases would have contained 5-10% of the total radioactivity
after extraction.
5.1.4. Radioactivity Measurements
The radioactive content of samples, fluid or dry, was measured by
96
-------
liquid scintillation counting in a Packard Model 2425 Tri-Carb Liquid
Scintillation Spectrometer. Fluid samples included stock solutions, extracts,
partition phases, eluates, filtrates and distillates. Scrapings from
chromatogram plates were the only dry samples counted directly. Aquasol was
used as the counting cocktail for all direct samples, and Permafluor V
(Packard Instrument Co., Inc., Downers Grove, IL) or Monophase-40 (Packard)
for samples processed in a Packard Model 306 Sample Oxidizer. The latter
samples were primarily soil and sediment phases from sorption isotherm
determinations. 1HC from oxidized samples was collected as ll*C02 in Carbo-
Sorb (Packard) and added to Permafluor V for counting; 3H from oxidized
samples was collected as 3H20 directly in Monophase-40. All samples were
counted for 10-minute periods. All counts were corrected for background
radioactivity and counting efficiency.
5.2. OCTANOL-WATER PARTITIONING PROCEDURE
The partitioning of a solute between two immiscible solvent phases has
become a handy reference characteristic. In addition, when the partitioning
of the solute into one phase (especially a volatile phase) is very much
greater than into the other phase, the technique becomes a useful means of
solute extraction. The literature contains numerous articles describing
partitioning methodology and interpretations. Portions of the methods of Leo
et al. (42), Chiou et al. (43), Karickhoff et al. (15) and Karickhoff (44)
were utilized in the present investigation to develop a procedure (Figure 5.1)
that gives reproducible results with organic compounds possessing limited
water solubility.
For compounds with known or predicted low water solubility, such as
the polynuclear aromatic hydrocarbons (PAH), the pure radiolabeled compound
was used without the addition of unlabeled compound in order to provide
significant levels of radioactivity in the aqueous phases. For compounds
with moderate-to-high water solubility, such as acetophenone or a-naphthol, a
sufficient quantity of pure unlabeled compound was added to the radiolabeled
compound to avoid excessively high levels of radioactivity in the octanol
phases.
Using a predicted Kow of the compound to calculate the quantity of
compound necessary to provide a statistically significant level of radio-
activity in the aqueous phase, a sufficient quantity of radiolabeled compound
was dissolved or diluted in a suitable solvent (e.g., acetone). An appropri-
ate amount of solution was shell-evaporated under a stream of N2 onto the
lower walls of each of triplicate foil-covered screw-capped Erlenmeyer flasks;
50-ml flasks were used for volumes ranging from 10 to 15 ml, and 500-ml
flasks for volumes ranging from 100 to 300 ml. Five ml of 1-octanol that had
been purified by the method of Karickhoff et al. (15) were added to each
flask. The flasks were shaken at moderate speed on a Burrell Wrist-Action
shaker at room temperature (24°C) for one to two hours to ensure full
dissolution of the compound in the octanol. Octanol-saturated ultrapure
(>10 megohm/cm) water was added to each flask at the rate of 5-10 ml for
moderately water-soluble compounds and 100-300 ml for the less water-soluble
compounds. The flasks were flooded with N2 and shaken at moderate speed for
15 minutes.
97
-------
Pure radiolabeled compound
I
Dissolve in suitable solvent
i
Shell-evaporate (under ^) on lower walls of
triplicate foil-covered screw-capped 500-ml Erlenmeyer flasks
Add 5 ml purified 1-octanol to each flask
i
Shake (wrist-action shaker), moderate speed, 1-2 hours, room temperature
I
Add 300 ml octanol-saturated ultrapure (>10 megohm/cm) water to each flask;
flood flasks with N2
Shake at moderate speed, 15 minutes, room temperature
I
Transfer upper portion of mixture to glass (Corex) centrifuge tubes;
centrifuge at 30,000xg, 20 minutes, 24°C;
discard lower (uncentrifuged) portion of mixture
i
Repeat centrifugation if interface is not clear
i
Sample octanol phase (10 yl in triplicate) for liquid scintillation counting;
remove and return octanol phase to original Erlenmeyer flask
I
Remove and discard all residual octanol at interface
(including some aqueous phase, if necessary)
Carefully sample aqueous phase (1.0 ml in triplicate)
for liquid scintillation counting
(make sure that pipette is wiped free of any residual octanol)
I
Calculate Kow
(Kow = dpm/ml octanol phase -f dpm/ml aqueous phase)
i
Repeat partitioning procedure with fresh octanol-saturated ultrapure water
until Kow value remains constant (indicative of compound purity)
I
By means of HPLC, determine % of radioactivity in aqueous phase
actually representing parent compound; correct Kow value accordingly
FIGURE 5.1. PROTOCOL FOR DETERMINING THE OCTANOL-WATER PARTITION COEFFICIENT
OF A HYDROPHOBIC ORGANIC COMPOUND
98
-------
The full contents of the small flasks were transferred to 15-ml Cor ex
centrifuge tubes for centrifugation. The contents of the large flasks were
transferred to appropriate-size Erlenmeyer flasks. When the bulk of the
octanol had risen to the surface, the upper portion of the mixture (including
all of the octanol phase and about 25 ml of the aqueous phase) was divided
between two 15-ml Corex tubes; the remaining aqueous phase was discarded.
Tubes and contents were centrifuged at 30,000xg for 20 minutes at 24°C. If
the interface between the two phases was not clear, centrifugation was re-
peated. The octanol phases were sampled (10 yl in triplicate) for liquid
scintillation counting, and then carefully removed and returned to their
original Erlenmeyer flasks.
All residual octanol, with some water phase, if necessary, was re-
moved from the centrifuge tubes and discarded. The aqueous phases were
carefully sampled (1.0 ml in triplicate) for liquid scintillation counting;
during this sampling, pipettes were wiped free of any residual octanol. The
remaining portions of the aqueous phases were carefully transferred to clean
vials in preparation for degradation checks, if necessary.
The octanol-water partitioning coefficient (Row) for each partitioning
was calculated by dividing the dpm/ml of octanol phase by the dpm/ml of
aqueous phase. The partitioning procedure was repeated with fresh octanol-
saturated water until the Kow values remained constant (indicative of com-
pound purity in the octanol phase).
Once the Kow values for the partitioning of a compound had become
constant, the octanol phase was analyzed for the presence of degradation
products by the procedure outlined in Section 5.4.2. In all cases purity of
the compound dissolved in the octanol phase was >99%. The aqueous phase
saved from the last partitioning was analyzed (by the degradation procedure
described in Section 5.4.2) for the percent of radioactivity actually
representing the parent compound. The level of radioactivity in the aqueous
phase was adjusted accordingly and the Kow value corrected. The octanol-
water partition coefficients determined by the above procedure for the 14
compounds in the present study are presented in Table 5.4.
5.3. WATER SOLUBILITY DETEBMINATION
Many procedures for determining the water solubilities of organic
compounds have been recorded in the literature. Portions of the methods of
Haque and Schmedding (45) and Mackay and Shiu (46) were utilized in the
present investigation to develop a procedure (Figure 5.2) that gives repro-
ducible results with organic compounds varying from relatively soluble to
almost insoluble in water.
A quantity of pure radiolabeled compound representing at least a 10-
fold excess (per 900 ml of water) over the predicted solubility level was
dissolved or diluted in an appropriate solvent (e.g., acetone) or measured
without dilution if already liquid (e.g., acetophenone). For compounds with
a predicted low water solubility, such as PAH, the radioactive stock solution
was used without the addition of unlabeled compound. For compounds with
moderate-to-high water solubility, such as acetophenone or a-naphthol, a
99
-------
TABLE 5.4. OCTANOL-WATER PARTITION COEFFICIENTS (Kow)
OF ENERGY-RELATED ORGANIC POLLUTANTS
Compound Kow
Pyrene 124,000 ± 11,000
7,12-Dimethylbenz[a]anthracene 953,000 ± 59,000
Dibenz[o,7z]anthracene 3,170,000 ± 883,000
3-Methylcholanthrene 2,632,000 ± 701,000
Dibenzothiophene 24,000 ± 2,200
Acridine 4,200 ± 940
2,2'-Biquinoline 20,200 ± 2,200
ISfl-Dibenzofo^karbazole 2,514,000 ± 761,000
Acetophenone 38.6 ± 1.2
1-Naphthol 700 ± 62
Benzidine 46.0 ± 2.2
2-Aminoanthracene 13,400 ± 930
6-Aminochrysene 96,600 ± 4,200
Anthracene-9-carboxylic acid 1,300 ± 180
sufficient quantity of pure unlabeled compound was added to the radioactive
stock to avoid producing an aqueous solution with an excessively high
(wasteful) level of radioactivity.
The dissolved or liquid compound was divided equally between nine foil-
covered screw-capped 250-ml Erlenmeyer flasks, thus providing at least a 10-
fold excess per flask over the predicted solubility level. The solution was
shell-evaporated (under N£) on the lower walls of the flasks. One hundred ml
of degassed (boiled) ultrapure (>10 megohm/cm) water were added to each flask.
Flasks were flooded with N2, capped, and shaken at moderate speed on a Burrell
Wrist-Action shaker at room temperature (24°C). Triplicate flasks were
removed at 24, 48 and 72 hours; for all of the compounds in the present
study, saturation was achieved within 24 hours. In order to ensure that any
increase in solubility was not due to degradation of the parent compound, a
100
-------
Pure radiolabeled compound
(allow at least 10-fold excess/flask over predicted solubility level)
I
Dissolve in suitable solvent
I
Shell-evaporate (under N2) on lower walls of
several (e.g., 9) foil-covered screw-capped 250-ml Erlenmeyer flasks
I
Add 100 ml degassed ultrapure (>10 megohm/cm) water to each flask
I
Flood flasks with N£
i
Shake (wrist-action shaker) , moderate speed, room temperature
I
Remove triplicate flasks at 24, 48 and 72 hours
(or later, if saturation level not reached yet)
i
Filter several successive 5-ml samples from flask
through same 0.2y Nuclepore filter; save filtrates
i
Sample each filtrate (1.0 ml in triplicate)
for liquid scintillation counting
Calculate solute concentration in each filtrate in terms of ppm or ppb;
average the values of successive filtrates containing similar solute levels
(disregard any early filtrates reflecting
adsorption of solute onto filter membrane)
I
Perform degradation check on 10-ml sample from at least one flask each day to
ensure that any increase in solubility is not due to compound degradation
FIGURE 5.2. PROTOCOL FOR DETERMINING THE WATER SOLUBILITY
OF A HYDROPHOBIC ORGANIC COMPOUND
101
-------
10-ml sample from at least one flask each day was analyzed for degradation
products by the procedure outlined in Section 5.4.3.
The flask contents were sampled (1.0 ml in triplicate) for liquid
scintillation counting. Several successive 5-ml samples from a flask were
filtered through the same 0.2y Nuclepore filter. (For all compounds in this
study, 0.2y and O.OSy Nuclepore filters gave identical results.) Each
filtrate was saved and sampled (1.0 ml in triplicate) for liquid scintillation
counting. Sequential filtrations were continued until the level of radio--
activity in the later filtrates remained constant. The first two or three
filtrates of the series usually contained less radioactivity than the sub-
sequent filtrates, probably because the compound was being adsorbed onto the
surface of the filter. For most compounds, the level of radioactivity in the
filtrates was less than in the unfiltered solution, probably reflecting the
retention of aggregates by the filter.
From the specific activity of the compound added to each flask and the
level of radioactivity present in the filtrates, the solute concentration in
each filtrate was calculated in terms of yg/ml (parts per million, ppm) . For
all nine flasks, the values of successive filtrates containing similar solute
levels were averaged. The water solubilities determined by the above pro-
cedure for the 14 compounds in the present study are presented in Table 5.5.
5.4. DEGRADATION STUDIES
It was noted early in the investigation that most of the compounds
were reasonably stable to atmospheric and photooxidation when present in high
concentration either in solution or on a sorbing surface. However, these
same compounds in dilute solution (e.g., aqueous solution) were much more
susceptible to degradation. In addition, even after purification, many of
the compounds tended to retain a small percentage of impurity (<3%) that was
usually a polar oxidation product and thus tended to stay in the more polar
or aqueous phases during any procedure. Because liquid scintillation counting
of a radioactive sample does not distinguish between parent compound and con-
tamination or degradation products present in the sample, it was necessary to
determine what percentage of the radioactivity actually represented the parent
compound. This was especially important for the very slightly soluble
compounds where the level of radioactivity in the aqueous phase of either a
sorption isotherm determination or an octanol-water partitioning was normally
very low in comparison to the level in the soil/sediment or octanol phase.
Even if only half of the radioactivity in the aqueous phase represented
parent compound, the resulting Kp or Kow value would be double that obtained
without correction for degradation. Thus the following procedures were
developed.
5.4.1. Sorption Isotherms
5.4.1.1. Soil/Sediment Phases
The soil/sediment phases were monitored for degradation products by
means of TLC. A small sample (^0.5 g) of soil/sediment phase, after centri-
fugation and removal of the aqueous phase, was suspended in 5 ml of acetone,
102
-------
TABLE 5.5. WATER SOLUBILITIES OF ENERGY-RELATED ORGANIC POLLUTANTS
Compound
Water Solubility
(Jig/ml)
Pyrene
7,12-Dimethylbenz[a]anthracene
Dibenz[a,h]anthracene
3-Methylcholanthrene
Dibenzothiophene
Acridine
2,2'-Biquinoline
13#-Dibenzo[o,-£]carbazole
Acetophenone
1-Naphthol
Benzidine
2-Aminoanthracene
6-Aminochrysene
Anthracene-9-carboxylic acid
0.135
0.013
0.0244 ± 0.0042
0.00249 ± 0.00081
0.00323 ± 0.00017
1.47 ± 0.14
38.4
1.02
± 4.5
± 0.12
0.0104 ± 0.0041
5440
866
360
1.30
0.155
85.0
± 71
± 31
± 8.0
± 0.159,
± 0.018
± 1.9
shaken well, allowed to stand several minutes, reshaken, and then banded
(^0.1 ml) across the origin of half of a 20x20-cm 0.5-mm-thick silica gel G
plate. The suspension of another soil/sediment was banded on the other half
of the plate. A small amount of unlabeled standard solution was spotted at
the origin between the two sample bands, and the plate was developed in the
appropriate solvent system (see Table 5.1). The location of the unlabeled
standard was visualized under UV light and recorded. One-cm segments from
the solvent front to the bottom of the plate were scraped from each sample
lane into vials of Aquasol for liquid scintillation counting. The quantity
of radioactivity in the segments corresponding to the unlabeled standard was
calculated as a percentage of the total radioactivity in the sample lane
(half-plate-width). For all compounds in the present study, >99% of the
radioactivity present in the soil/sediment phases represented parent compound.
103
-------
5.4.1.2. Aqueous Phases
The aqueous phases that had been removed from the isotherm tubes after
centrifugation and sampling were re-centrifuged at 30,000xg for 20 minutes in
preparation for high pressure liquid chromatographic (HPLC) analysis. A
Waters HPLC system consisting of a Model 660 Solvent Programmer and two Model
6000A Solvent Delivery Systems was operated in conjunction with a Schoeffel
Model FS 970 L.C. Fluorometer for monitoring the eluate from the column. The
chromatograph was fitted with a 5-ml injection loop and a yBondapak Cjg
column, and operated at a flow rate of 2 ml/min. Suitable gradient and
elution conditions for each compound were established using unlabeled standard
solution to locate the appropriate fluorescent peak and a solution of pure
radioactive compound to locate the fractions containing the parent compound.
A 5-ml aqueous phase sample was injected; the pumps were programmed to
deliver 20 ml of water to flush all sample components not adhering to the
column from the system. This was followed by the appropriate water-to-
methanol gradient to elute the parent compound and any contaminants and
degradation products in a reasonable length of time. The water flush was
collected as three 6.3-ml fractions and the gradient eluate as multiple 1-ml
fractions in vials containing Aquasol for liquid scintillation counting. The
quantity of radioactivity in the fractions corresponding to the fluorescent
parent peak was calculated as a percentage of the total radioactivity in all
of the fractions. The concentration of radioactive components in the isotherm
aqueous phase was then corrected to reflect parent compound concentration.
During a period when the HPLC system was non-functional, an alternate
procedure for determining the percent degradation in the aqueous phases of
acridine isotherms was developed utilizing preparative TLC. Approximately
eight 0.5-ml aliquots of the aqueous phase were banded across the origin of a
20x20-cm 0.5-mm-thick silica gel G plate, with gentle but complete drying
(heat gun) between and after applications. Unlabeled standard solution was
spotted at a few locations across the origin. The plate was developed in
benzene:methanol (95:5, v/v) to the scribed solvent front mark. Standard
spots were located under UV light and their positions recorded. The plate
was scored into horizontal 1-cm-wide segments from the solvent front to the
bottom of the plate; each segment was scraped into a separate vial of Aquasol
for liquid scintillation counting. The quantity of radioactivity in the
segments corresponding to the unlabeled standard spots was calculated as a
percentage of the total radioactivity on the plate. The concentration of
radioactive components in the aqueous phase was then corrected to reflect
parent compound concentration. The degradation study on acridine isotherm
aqueous phases was repeated using the HPLC system when it was again functional.
The two procedures gave comparable results,
5.4.2. Octanol-Water Partitionings
5.4.2.1. Octanol Phases
The octanol phase of the final partitioning of each compound was
monitored for degradation products by means of TLC. A small quantity (^5 yl)
of the octanol phase was spotted along with a small amount of unlabeled
standard solution at the origin of a 5x20-cm 0.25-mm-thick silica gel G plate.
104
-------
The plate was developed in the appropriate solvent system, scraped, and
analyzed as indicated above. For all compounds in the present study, >99% of
the radioactivity present in the octanol phase represented parent compound.
5.4.2.2. Aqueous Phases
The aqueous phase of the final partitioning of each compound was
analyzed for degradation products by HPLC in a manner similar to that used
for the analysis of isotherm aqueous phases described earlier in this section.
The level of radioactivity in the aqueous phase was adjusted accordingly to
reflect parent compound radioactivity before final calculation of the Row.
5.4.3. Water Solubilities
A 10-ml sample from a solubility flask was extracted with three 5-ml
volumes of an appropriate solvent (e.g., ether for PAH, methylene chloride
for N-heterocyclic compounds). The volume of the extracted aqueous phase
remained at 10 ml; the volume of the extract was recorded. Both the ex-
tracted aqueous phase and the extract were sampled in triplicate (1.0 ml for
the former, 0.2 ml for the latter) for liquid scintillation counting. The
extract was concentrated under N2 to a small volume (^1 ml); a small quantity
of extract (^0.02 ml) was spotted along with a small amount of unlabeled
standard solution at the origin of a 5x20-cm 0.25-mm-thick silica gel G plate.
The plate was developed in the appropriate solvent system, scraped, and
analyzed as indicated above. For each compound in the present study, the
degradation checks of all flasks yielding similar solubility levels after
several filtrations revealed that >98% of the total radioactivity was solvent-
extractable, and >98% of the radioactivity in the extract represented parent
compound.
105
-------
SECTION 6
SAMPLE SELECTION AND CHARACTERIZATION
6.1. CRITERIA FOR SAMPLE SELECTION
Sampling sites were chosen by two major criteria: (1) to be in close
proximity to and downstream from potential coal gasification sites, (2) to
provide a wide range in soil and sediment properties that have been shown to
affect the degree of adsorption of organic compounds. Eight sites in the
United States have been identified as areas of high potential for gasification
development (Map 6.1). These include Jefferson, Harrison and Belmont counties
in Ohio; Washington and Greene counties in Pennsylvania; Marshall, Marion and
Monongalia counties in West Virginia; Hopkins, Muhlenberg, Webster, Union and
Henderson counties in Kentucky; St. Clair, Washington, Saline, Gallatin,
Hamilton, Williamson, Perry, Madison, Sangamon, Christian, Macoupin, Mont-
gomery, Bond, Vermilion, Edgar, Knox, Fulton and Peoria counties in Illinois;
San Juan county in New Mexico; Big Horn, Rosebud, Powder River and Custer
counties in Montana; Campbell and Johnson counties in Wyoming; and Dunn and
Mercer counties in North Dakota.
These areas with the exception of sites in New Mexico, Montana and
Wyoming are in the Missouri, Mississippi, Illinois, Wabash and Ohio River
watersheds. Hence, sample collection was centered on these rivers and their
watersheds (Map 6.2). In addition to being in close proximity to or downstream
from potential coal gasification sites, these sites also provided a wide
variation in properties which have been shown to be related to the capacity
of soils and sediments to adsorb various materials. At several sites an
effort was made to collect sediment samples as well as soil samples represen-
tative of major soils in the corresponding watershed. Locations of each
sampling site and some pertinent field notes are given in Table 6.1.
TABLE 6.1. FIELD NOTES
a
Sample Notes
EPA-4 Sediment sample from Missouri River, north side of Sakakawea Park.
Stanton, North Dakota. Dark-grayish silty material with some fine
sand.
EPA-5 Sediment sample from Beaver Creek public use area of Lake Oahe on
the Missouri River eighteen miles west of Linton, North Dakota.
Appears to be an inundated soil, as sample had noticeable structural
development.
106
-------
TABLE 6.1. FIELD NOTES - Continued
Sample Notes
EPA-6 Sediment sample from Antelope Creek public use area in lake behind
Big Bend Dam on Missouri River, southwest of Pierre, South Dakota.
Sample is a grayish clayey material with a fair silt content.
EPA-8 Sediment sample taken from Missouri River near bridge across river,
Onawa exit 1-29, Iowa side of river. Sample taken next to main
channel; high velocity of flow in channel; sample extremely sandy.
EPA-9 Loess sample taken from bluff just north of Turin, Iowa.
EPA-14 Soil taken from a highly eroded red clay hillside southeast of
mouth of Big Sandy River near Ohio River. Point Park, Ceredo, West
Virginia.
EPA-15 Sediment taken from Ohio River three miles south of Leavenworth,
Indiana, at base of steep bluffs in Harrison Crawford State Forest.
Silty material.
EPA-18 Sediment taken from haIf-submerged clay lens in the Mississippi
River, next to ferry on Kentucky Route 80, near Columbus, Kentucky.
EPA-20 Soil sample taken from an old field succession, south of scenic
overlook exit, Feme Clyffe State Park, Illinois. Soil series
undetermined.
EPA-21 Sediment taken from a small river (creek) feeding Illinois River.
Sample taken two miles east of Lorenzo, Illinois, where highway
crosses the creek.
EPA-22 Sediment taken from large shallow bay of the Illinois River south
of bridge across river at Lacon, Illinois. Silty material.
EPA-23 Sediment taken from Crane Lake north of Blind number 63, Sanganois
Wildlife Refuge, confluence of Sangamon and Illinois Rivers.
EPA-26 Sediment from wide side channel of the Mississippi River by private
ferry across channel near McClure, Illinois.
EPA-B2 Sediment sample taken from a small stream roughly one-quarter mile
below the P-l watershed on the Southern Piedmont Conservation
Research Center (USDA) farm in Oconee County near Watkinsville,
Georgia. Stream essentially originates at the terminus of the
watershed and drains the watershed.
Samples EPA-4 through EPA-26 collected by W. L. Banwart and J. J. Hassett;
sample EPA-B2 collected by D. S. Brown.
107
-------
r
MAP 6.1. AREAS OF HIGH POTENTIAL FOR COAL GASIFICATION DEVELOPMENT
Modified from Siting Potential for Coal Gasification Plants in the United States,
by A. E. Lindquist (6).
-------
MAP 6.2. SAMPLING SITES ON THE MISSOURI, OHIO, WABASE, ILLINOIS AND
MISSISSIPPI RIVER SYSTEMS AND THEIR WATERSHEDS
109
-------
6.2. SAMPLE CHARACTERIZATION
Table 6.2 gives the pH, cation exchange capacity, percent total nitro-
gen and organic carbon as well as textural information for the samples col-
lected. Soil reaction, pH, was determined on 1:1 and 1:2 soil-water mixtures
by the method of Peech ( 47 ) . Cation exchange capacity was determined by the
ammonium acetate method as modified by Banwart and Hassett ( 48 ) . Total ni-
trogen was determined by the method given by Bremner ( 49 ) with the exception
that the entire digestion sample was distilled rather than an aliquot. Or-
ganic carbon was determined by the Walkley-Black method as given by Allison
(50). Particle size analysis was determined by the hydrometer method of Day
( 51 ) using hydrogen peroxide to destroy the organic matter ( 52 ).
TABLE 6.2. CHARACTERISTICS OF SOILS AND SEDIMENTS
EPA- 4
EPA-5
EPA- 6
EPA- 8
EPA-9
EPA- 14
EPA- 15
EPA- 18
EPA- 20
EPA-21
EPA- 2 2
EPA- 23
EPA- 2 6
EPA-B2
PH
(1:1)
7.79
7.44
7.83
8.32
8.34
4.54
7.79
7.76
5.50
7.60
7.55
6.70
7.75
6.35
PH
(1:2)
8.22
7.20
8.23
8.56
8.55
4.30
7.80
7.79
5.16
7.95
7.90
7.10
8.10
6.50
CEC
(me/lOOg)
23.
19.
33.
3.
12.
18.
11.
15.
8.
8.
8.
31.
20.
3.
72
00
01
72
40
86
30
43
50
33
53
15
86
72
Total N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.190
.192
.097
.010
.015
.064
.092
.062
.126
.157
.128
.195
.152
.073
Organic
carbon
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
1.21
Sand
3.0
33.6
0.2
82.4
7.1
2.1
15.6
34.6
0
50.2
26.1
17.3
1.6
67.5
Clay
55.2
31.0
68.6
6.8
17.4
63.6
35.7
39.5
28.6
7.1
21.2
69.1
42.9
18.6
Silt
41.
35.
31.
10.
75.
34.
48.
25.
71.
42.
52.
13.
55.
13.
8
4
2
7
6
4
7
8
4
7
7
6
4
9
110
-------
6.2.1. Instrumental Neutron Activation Analysis (INAA)
The basic concept of INAA is that a small fraction of the stable
nuclei present in a sample becomes radioactive when bombarded with neutrons
in the 1.5 MW TRIGA reactor. In many of the subsequent radioactive decay
processes, one or more high energy photons or gamma rays are emitted. A high
resolution semiconductor detector interacts with a gamma ray and yields a
pulse with the maximum voltage of the pulse being proportional to the gamma
ray energy. This pulse is amplified and shaped and then sorted by a pulse
height analyzer so that various energy gamma rays result in counts in dif-
ferent locations in a computer-like memory. The energy of a gamma ray is
unique to a particular isotope of a specific element so that a qualitative
analysis can be made by observing the spectrum of gamma ray energies emitted
by the activated samples. A quantitative analysis can be made by relating
the number of gamma rays emitted by the sample relative to a standard con-
taining a known amount of that element.
Approximately 100 mg of the solid sample are weighed out into a pre-
cleaned polyethylene container. A standard is prepared by pipetting a small
known quantity of an aqueous solution containing a known concentration of the
element of interest onto a Whatman No. 41 filter in a clean polyethylene con-
tainer. The standard is irradiated simultaneously with the sample. The
gamma ray spectra from a series of samples and standards are recorded on mag-
netic tape. A fully automatic computer code then reduces the counting data
to elemental concentrations. A list of elements and their interference-free
limits of detection is given in Table 6.3. Table 6.4 gives the results of
INAA analysis of the soil and sediment samples.
6.2.2. Clay Mineral Analysis
Twenty-gram samples of the soils and sediments were pretreated with
200 ml of NaOCl (pH 9.5) to remove organic matter according to the method of
Anderson (53). Samples were placed in a nearly boiling water bath and con-
stantly stirred until the reaction was complete. The suspension was centri-
fuged at 5,000 rpm for 5 minutes and the supernatant decanted. The solid
residue was then treated with 200 ml of IN NaOAc (pH 5) and placed in a
nearly boiling water bath for one hour to facilitate removal of the carbonate
cementing agents. The solid residue after centrifugation and decantation of
the supernatant was treated by the method of Mehra and Jackson (54) using
160 ml of 0.3M sodium citrate, 20 ml of 1M NaHCOs and 2 grams of solid sodium
dithionate to remove the amorphous cementing agents.
A portion of the residue remaining after removal of the organic matter,
carbonates and amorphous materials was saturated with Mg2+ ions to facilitate
uniform interlayer water adsorption of the expandable layer-silicates. A
second portion of the residue was saturated with K ions, thus restricting
water adsorption by the normally expandable layer-silicate vermiculite.
These K+ and Mg2+-treated samples were then washed twice with methanol and
twice with acetone to remove excess salts.
Ill
-------
TABLE 6.3. ELEMENTAL LIMITS OF DETECTION BY INSTRUMENTAL NEUTRON ACTIVATION
ELEMENT
Aluminum
Antimony
Arsenic
Barium
Bismuth
Bromine
Cadmium
Calcium
Cerium
Cesium
Chlorine
Cobalt
Copper
Dysprosium
Europium
Gallium
Gold
Hafnium
Indium
Iodine
Iridium
Iron
Lanthanum
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Niobium
Potassium
Rubidium
Samarium
Scandium
Selenium
Sodium
Strontium
Tantalum
Terbium
Thallium
Thorium
Titanium
Tungsten
Uranium
Vanadium
Zinc
Zirconium
INAA (yg)
0.004
0.007
0.005
0.02
0.003
0.005
4.
0.2
0.001
0.05
0.01
0.00003
0.0001
0.002
0.0005
0.0006
0.00006
0.002
0.0003
2.
0.005
0.5
0.0001
0.003
0.1
0.7
3.
0.2
0.02
0.001
0.001
0.01
0.004
0.005
0.1
0.03
0.2
0.1
0.004
0.003
0.002
0.1
0.8
112
-------
TABLE 6.4. INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS OF SOILS AND SEDIMENTS
As
Ba
Br
Ce
Co
Cs
Dy
Eu
Ga
Hf
Hg
La
Lu
Mn
Nd
Ni
Rb
Sb
Sc
Se
Sr
Ta
Tb
Th
U
Yb
Zr
EPA-B2
(yg/g)
<17
383
<2.2
84
8.2
1.5
4.1
1.22
12
10.4
-
40.4
0.37
1140
27
-
72
0.18
7.58
<0.4
<78
0.66
1.0
10.9
2.6
2.54
271
EPA-4
(yg/g)
5.2
671
<2.6
59.8
12.45
4.55
3.45
0.948
6.7
5.22
-
31.2
0.62
818.8
24
-
80.0
1.31
11.52
0.44
43
0.83
0.68
9.03
-
1.841
40
EPA-5
(yg/g)
11.8
788
<3.4
61.3
8.89
3.24
3.83
1.026
10.8
7.49
-
25 .i 4
0.38
392.1
36
-
66.7
6.78
7.662
1.53
171
0.540
0.64
8.65
-
2.110
102
EPA-6
(yg/g)
12.9
1183
<3.0
55.1
19.11
4.62
<0.8
1.020
5.7
6.13
-
33.8
-
4300
19.0
-
105
2.14
9.349
1.19
338
0.48
0.70
8.25
-
1.850
174
• — - - --
EPA-8
(yg/g)
9.8
830
<1.9
41.1
5.96
1.27
2.10
0.304
7.2
7.81
-
21.6
-
347.8
31
-
62.4
0.51
3.739
<0.19
260
0.314
0.460
5.74
-
1.424
410
EPA-9
(yg/g)
4.6
872
<2.3
65.9
10.88
2.98
3.17
1.296
8.7
12.25
-
30.6
-
764.8
53
-
97
1.25
6.895
0.89
299
0.54
0.368
9.47
-
2.64
37
EPA- 14
(yg/g)
9.9
450
-
86.9
11.00
7.97
4.49
0.943
22.9
8.03
-
46.1
-
216.1
43
-
200
6.05
16.15
1.88
<80
1.08
0.959
14.61
-
2.93
249
% % % % % % "/<•
Ca
Fe
K
Na
0.84
2.18
1.00
0.771
2.02
3.100
1.778
0.7556
1.41
2.508
1.657
1.081
1.44
3.039
1.331
0.6590
1.39
1.257
1.324
1.051
3.08
2.300
1.455
0.922
0.51
4.888
2.453
0.1529
113
-------
TABLE 6.4. Continued
As
Ba
Br
Ce
Co
Cs
Dy
Eu
Ga
Hf
Hg
La
Lu
Mn
Nd
Ni
Kb
Sb
Sc
Se
Sr
Ta
Tb
Th
U
Yb
Zr
EPA- 15
(yg/g)
7.4
451
-
90.1
20.21
3.95
5.81
1.549
7.1
15.63
-
43.5
-
1197
36
-
115
<0.48
10.97
1.75
272
1.37
0.734
12.50
-
3.33
524
EPA- 18
(yg/g)
9.5
466
-
75.6
14.63
3.81
4.92
1.163
13.6
9.50
-
38.9
1.28
1205
34
-
73
0.82
8.542
1.31
<103
0.69
0.63
9-22
-
2.21
254
EPA- 20
(yg/g)
4.7
774
-
76.4
14.83
2.27
4.63
1.575
<3.1
14.23
<0 . 030
38.6
-
2322
44
-
95
0.26
5.582
0.30
<164
0.532
0.53
9.92
-
2.55
-
EPA- 21
(yg/g)
<16
349
<2.4
7.9
10.7
3.7
3.2
0.77
9.4
4.7
-
26.4
0.32
556
9.9
-
96
0.38
7.75
<0.5
<66
0.57
0.53
7.3
1.5
1.73
<62
EPA- 2 2
(yg/g)
<16
415
<2.8
40.2
8.2
2.4
3.7
0.96
<4.2
6.9
-
24.2
0.77
727
30
-
74
1.1
6.06
1.5
303
0.31
0.59
6.4
<0.6
1.96
248
EPA- 2 3
(yg/g)
8.1
544
10
63.0
10.8
5.8
3.9
1.14
16
2.0
-
26.8
0.16
695
34
-
140
0.52
12.41
<0.5
<67
0.72
<0.05
11.2
1.2
1.49
139
EPA- 26
(yg/g)
<26
595
5.4
73.3
11.1
5.0
5.4
1.26
<4.8
7.3
-
37.8
0.29
1102
25
-
103
0.94
9.60
1.0
363
0.96
0.83
11.2
4.4
2.52
185
%%%%%%%
Ca
Fe
K
Na
1.18
3.607
1.860
0.4682
0.89
2.804
1.641
0.5233
<0.14
1.626
1.73
0.7319
1.66
2.46
1.96
0.625
2.83
2.16
1.51
0.71
1.34
3.70
1.74
0.327
1.36
2.71
1.9
0.78
114
-------
Parallel oriented specimens were prepared using the method of Theisen
and Harvard (55). Prepared specimens were subjected to X-ray diffraction
analysis. A Phillips-Norelco X-ray diffractometer equipped with a digital
stepping motor was used. X-rays were detected by a Nal scintillation detector;
signals were analyzed, digitized and interfaced to a T.I. ASR 733 perminal
using a Canberra model 654 Datamini system.
Diffractograms for the 14 samples were run using the Mg2+-saturated
slides to obtain relative amounts of different clay minerals present (Table
6.5). The relative amounts of montmorillonite or vermiculite, illite and
kaolinite were determined by calculating the area under their respective
peaks on the diffractograms. To further identify the crystalline clay
minerals present and to semiquantitatively determine the amount of the
various minerals present, step scanning was used over a range of 6 to 20
angstroms. In the step scanning mode, counts were accumulated for 10 seconds
at step size increments of 0.01° (20). Data were accumulated on magnetic
tape for computer analysis.
TABLE 6.5. QUALITATIVE DETERMINATION OF THE DIFFERENT CLAY MINERALS3 IN THE
LESS-THAN-2]a FRACTION OF THE SOIL AND SEDIMENT SAMPLES
Sample Montmorillonite Kaolinite Total Clayb
or Vermiculite (%)
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
T!
D3
D4
D4
D4
D4
Dl
Dl
D3
D3
Dl
D3
D4
D4
T
T
T
T
T
T
Dl
Dl
T
T
Dl
T
T
T
D3
T
T
T
T
T
D2
D2
T
T
Dl
Dl
T
T
18.6
55.2
31.0
68.6
6.8
17.4
63.6
35.7
39.5
28.6
7.1
21.2 ...
69,1
42.9
aT = <20% of total clay; Dl = 20-40%; D2 = 40-60%; D3 = 60-80%; D4 = 80-100%.
bFrom Table 6.2.
115
-------
9^U
Because the initial diffractograms obtained were for Mg -saturated
air-dried samples, additional analysis was necessary to positively identify
the minerals present. For example, a diffraction spacing of VL4A on Mg2+-
saturated slides may be due to the presence of montmorillonite, vermiculite
or chlorite or a mixture of these species. Positive identification of mont-
morillonite, a swelling 2:1 layer-silicate, was obtained by treating the clay
sample with ethylene glycol resulting in a shift of the 14-15A peak to 17A.
The shift is due to penetration of the ethylene glycol into the clay inter-
layer which results in expansion of the interlayer. Because vermiculite and
chlorite would be expected to give essentially identical results with their
Mg2+-saturated slides, positive identification of these minerals was accom-
plished using the K+-saturated samples. The diffraction peak of heated K -
saturated slides occurs at 10A for vermiculite and at 14-15A for chlorite.
Illite was identified by a first order peak at 8.9 to 10.5A and a
second order peak at 4.5A (56). Kaolinite was by far the dominant mineral in
some samples such as EPA-B2 and was identified by a 7.0 to 7.2A peak (57).
This peak was positively identified by its disappearance upon heating the
Mg -saturated specimen to 500°C. Table 6.6 gives the results of the step
scores in terms of a semiquantitative determination of amounts of kaolinite,
illite and vermiculite or montmorillonite present.
6.2.3. Amorphous Al, Fe and Si
Amorphous mineral colloids occur extensively in soils (58). The
commonly used methods of characterizing them is based upon their relative
resistances to dissolution in various alkaline solutions. Amorphous Al and
Si were extracted in 0.5M NaOH. One-gram samples of the soils or sediments
were placed in stainless steel beakers and heated in a constant temperature
water bath at 95 °C for five minutes. After cooling, the suspensions were
brought to exactly 100-ml volume with NaOH. Silica was determined by molyb-
denum blue color development. Aluminum was determined by atomic absorption
spectroscopy (Perkin Elmer model 305b) using a nitrous oxide acetylene flame.
Iron was extracted with buffered citrate-dithionate solution. The
procedure used for extractable Fe was essentially that of Mehra and Jackson
(54) with the following modifications. Samples were placed in an 80°C water
bath after addition of the extracting solution for exactly 5 minutes, fol-
lowed by the addition of 1 gram of dithionate powder and an additional 15-
minute reaction time.
Amorphous silica ranged from 0.09 to 0.44 percent, amorphous aluminum
ranged from 0.01 to 0.25 percent, and amorphous iron ranged from 0.22 to 1.38
percent (Table 6.7).
A simple correlation of selected sediment and soil properties is given
in Table 6.8. It is interesting to note that CEC is significantly correlated
with total clay but not with organic carbon. As would be expected, pH is
negatively correlated with amorphous Fe and Al although more than half of the
samples collected had pH values greater than 7. While organic carbon does
not correlate with CEC, it is significantly correlated with total N, as would
be expected.
116
-------
TABLE 6.6. SEMIQUANTITATIVE DETEKMINATION OF CLAY MINERALS IN THE
SOILS AND SEDIMENTS.
Sample
B2
4
5
6
8
9
14
15
18
20
21
22
23
26
Montmorillonite
or Vermiculite
(%)
2.0
40.1
25.7
60.8
6.1
16.3
13.8
10.1
29.7
21.9
2.8
14.8
57.6
37.1
(v)a
(M)
00
(M)
(M)
(M)
(V&M)
(V&M)
(M)
(M)
(M)
(M)
(M)
(M)
• • - • -
Illite
00
2.7
5.7
1.8
4.6
0.2
0.4
12.8
10.4
2.8
2.1
1.6
2.1
4.2
1.7
~*mmm*~^mmmmmimmm~ii~~*mmmm~*^^^^^**^^^*^i^^^^^~^^*-*~~*^^~
Kaolin! te
(%)
13.9
9.4
3.5
3.2
0.5
0.7
37.0
15.2
7.0
4.6
2.7
4.3
7.3
4.1
a(V) = vermicullte; (M) = montmorillonite.
117
-------
TABLE 6.7. SODIUM HYDROXIDE-EXTRACTABLE Si AND Al AND CITRATE-DITHIONATE-
EXTRACTABLE Fe IN THE SOIL AND SEDIMENT SAMPLES
Sample
Si
Al
Fe
B2 0.12
4 0.18
5 0,12
6 0.44
8 0.08
9 0.26
14 0.10
15 0.09
18 0.10
20 0.16
21 0.12
22 0.09
23 0.21
26 0.29
0.25
0.07
0.03
0.03
0.01
0.02
0,20
0.10
0.05
0.14
0.05
0.05
0.12
0.13
0.88
0.71
0.49
0,59
0.22
0.59
1.38
1.27
0.74
0.61
0.60
0.61
0.73
0.63
TABLE 6.8. CORRELATION MATRIX OF SELECTED SAMPLE CHARACTERISTICS
CO
D
O
S3
O
CEC
%N
%OC
%Clay
%Si
%Fe
%A1
0
-0
-0
-0
0
-0
-0
PH
.002
.076
.063
.318
.223
.559a
u
.774b
CEC
0
0
0
0
0
-0
.470
.304
.898b
h
.678b
.090
.106
%N
0.
0.
0.
-0.
0.
%OC
964b
344
097
063
037
0.
-0.
-0.
0.
181
062
105
077
AMORPHOUS
%Clay %Si %Fe
0.484
0.419 -0.215
v>
0.218 -0,164 0.631b
Significant at 5% level
'Significant at 1% level
118
-------
6.3. EFFECT OF SAMPLE PRETREATMENT ON SORPTION OF ACETOPHENONE BY SEDIMENTS
Sediment or soil samples can be handled various ways from the time
they are collected until laboratory analyses are performed. Probably the
most commonly used pretreatment method is to air-dry samples and pass them
through a 2-mm sieve prior to storage and subsequent treatment or analysis.
Samples are sometimes oven-dried or freeze-dried to "preserve" the integrity
of the sample and/or for the convenience of the experimenter.
While the effect of sample pretreatment on the sorption of aceto-
phenone has not been reported, several studies have shown sample pretreatment
to have significant effects on soil physical and/or chemical properties, such
as levels of available nutrients in soils (59,60,61,62). Thien et al. (63),
for example, reported that soil pretreatment significantly affects pH,
nitrate nitrogen, extractable micro and macronutrients but not organic
carbon or clay mineralogy. Sertsu and Sanchez ( 62 ) concluded that heating
at 200°C did not alter clay mineralogy but did result in some organic carbon
decomposition and changes in soil pH and extractable nutrients.
Soil samples are commonly ground or crushed to pass a 2-mm sieve after
drying and prior to storage for analysis. For certain chemical tests such as
total carbon, however, soils are often ground to pass a 60-mesh sieve prior
to analysis. Data by Soltanpour et al- ( 64, 65 ) show that both grinding
force and grinding time played a significant role in DTPA micronutrient soil
tests but the effect of grinding fineness on sorption of acetophenone or
other organic compounds has not been reported.
Acetophenone was employed as a test compound for this study. It
represents one class of compounds, aromatic ketones, which have been shown to
be present in coal gasification wastes. These wastes represent a potential
for adding a wide variety of organic substances to the environment. Results
of this study were needed to evaluate the use of air-dried soil and sediment
samples in sorption studies.
Khan et al. ( 16 ) reported that sorption of acetophenone was highly
correlated with organic carbon content of soil and sediment samples whereas
other chemical or physical properties determined were not. They also specu-
lated that the amount and type of clay might be important in samples where
organic carbon was low. Sorption of certain pesticides is highly dependent
on the amount of organic matter in soils (66,67,68,69,70,71).
The purpose of this study was to examine the effect of (a) sample
pretreatment, (b) extent of grinding, and (c) organic matter destruction on
sorption of acetophenone by soils and sediments.
6.3.1. Experimental Methods
The Crane Island and Sangamon samples (Table 6.9) were collected from
the Illinois River near Crane Island and from the Sangamon River near Mahomet,
Illinois. Bulk samples were removed, mixed by hand, cooled to 2°C and taken
immediately to the laboratory. Samples were mechanically mixed and subdivided
119
-------
TABLE 6.9. SELECTED CHEMICAL AND PHYSICAL PROPERTIES OF RIVER SEDIMENTS.
Sample
Sangamon
Crane Island
Organic
Carbon
(%)
2.08
3.16
Silt
(%)
48
12
Total
Clay
(%)
35
69
for further experimentation. One subsample was stored at 2°C, a second sub-
sample frozen, a third subsample air-dried, a fourth subsample freeze-dried,
and a fifth subsample oven-dried at 110°C for 48 hours. Air-dried, freeze-
dried, and oven-dried samples were ground to pass a 2-mm sieve and stored for
further analysis.
In a second study, another air-dried sample was subdivided and por-
tions ground to pass through 2, 0.6 and 0.25-mm sieves to examine the effect
of particle size on sorption of acetophenone.
In a third study designed to examine the effect of organic matter
removal on sorption of acetophenone, 14 additional soil and sediment samples
described in Section 6.2 were air-dried and ground to pass a 2-mm sieve.
Organic matter was removed from these samples by treatment with NaOCl
(pH =9.5) according to the method of Anderson (53). The samples were then
washed with deionized water and subsequently saturated with calcium. After
calcium saturation the samples were air-dried and ground to pass a 2-mm sieve.
Organic carbon determinations were performed by the Walkley and Black method
( 50 ) on both the original air-dry samples and on samples after treatment to
remove organic matter.
Batch equilibrium sorption isotherms were determined for samples
stored at 2°C, frozen, air-dried, freeze-dried, and oven-dried to examine the
effect of sample processing and sample pretreatment. Similar isotherms were
run on air-dried samples ground to three different mesh sizes and on the
fourteen samples before and after treatment with NaOCl to remove organic
matter. Radiolabeled ll*C-acetophenone (99% pure) obtained from ICN
Pharmaceuticals Inc. and unlabeled acetophenone (99% pure) from Eastman Kodak
Co. were used for adsorption studies. Purity was verified using thin-layer
chromatography. A stock solution (4154 yg/ml) was prepared in ultrapure
distilled water. A minimum of triplicate adsorption isotherms were
determined using 2:5 solid to solution ratio with initial concentrations
varying from 138 to 1108 yg/ml. The isotherms were run in stainless steel
centrifuge tubes (teflon-covered lids) in a temperature-controlled shaking
water bath at 25°C for 24 hours. Initial and final concentrations of
acetophenone in the solution phase were determined using a Packard Model 3330
120
-------
liquid scintillation spectrometer. The concentration of acetophenone in the
soil/sediment phase (yg/g) was determined by difference.
6.3.2. Results and Discussion
6.3.2.1. Sample Pretreatment
Sorption of acetophenone on fresh (2°C), frozen, air-dried, freeze-
dried and oven-dried samples in the sample pretreatment study followed a
linear trend exemplified by sample isotherms shown in Figure 6.1. The
sorption isotherms gave a good fit to the modified Freundlich equation:
Cs = Kp-Cw (4-1)
where Cs id the amount adsorbed on the sediment in yg/g, Cw is the equili-
brium concentration in yg/ml, and Kp is the linear partition or sorption
constant. The correlation coefficient (r2) between Cs and Cw was determined
for individual pretreatments and ranged from 0.98 to 1.00 for the five
pretreatments tested. These correlations support the observation of linear-
ity of isotherms obtained for acetophenone sorption on soils and sediments by
Khan et al. ( 16 ).
The Kp values for the sample pretreatment studies are shown in Table
6.10. Individual Kp values ranged from 0.84 to 1.07 for Sangamori samples
TABLE 6.10. EFFECT OF SAMPLE PRETREATMENT ON MODIFIED
FREUNDLICH PARTITION COEFFICIENTS (Kp).
Sample
Sangamon
Crane Island
Fresh
1.07
0.90
Frozen
1.07
0.99
Kp
Air-dried
0.95
1.04
Freeze-dried Oven-dried
0.92 0.84
1.09 1.09
Mean3 0.98 1.03 1.00 1.01 0.97
are not significantly different at the 5% level.
and from 0.90 to 1.09 for Crane Island samples but no consistent trends could
be associated with any of the sample pretreatment techniques studies. The Kp
for the oven-dried Sangamon sample appeared to be slightly lower (0.84) than
the Kp for fresh, frozen, air-dried, or freeze-dried but the difference was
not significant at the 5% level of probability. The mean Kp values for the
two sediments studied ranged from 0.97 to 1.03 with none of the individual
sample pretreatment techniques resulting in Kp values significantly different
from the others.
121
-------
800-
600-
•400-
o
200-
FRESH
AIR-DRIED
200 400
Cw
600 800
FIGURE 6.1. COMPARISON OF ISOTHERMS FOR THE SORPTION OF ACETOPHENONE RY
FRESH AND AIR-DRIED SAMPLES OF CRANE ISLAND SEDIMENT
122
-------
Since organic carbon content has been shown to be the dominant soil
characteristic on which acetophenone sorption depends (16), organic carbon
determinations were carried out on each of the pretreatment subsamples used
for isotherm analysis. The organic carbon content was nearly identical for
all pretreatments except oven-drying. The organic carbon content, as
measured by the Walkley-Black method, in the oven-dried samples was 0.4 and
0.1 percent lower for the Crane and Sangamon samples, respectively. Thus,
while oven-drying had the greatest effect on the organic carbon content of
the Crane sample, this was not reflected in the Kp of this sample.
For ease of storage or handling, air-dried samples are commonly used
in sorption studies. The results of these studies imply that sorption of
acetophenone by air-dried samples is very similar to that by samples in their
natural or fresh condition and samples that have been frozen or freeze-dried.
Thus laboratory pretreatment of the kind tested here appears to have no
significant effect on the sorption of this compound.
6.3.2.2. Effect of Extent of Grinding
A separate air-dried subsample of two sediments was used to examine
the effect of extent of grinding on sorption of acetophenone. These results
(Table 6.11) show that samples ground to pass through a 2-mm maximum diameter
TABLE 6.11. EFFECT OF EXTENT OF GRINDING ON SORPTION (Kp) OF ACETOPHENONE
Mesh size of sieve to pass sample
10 30 60
Sample (2 mm) (0.6 mm) (0.25 mm)
Sangamon
Crane Island
0.99
0.99
0.88
1.13
0.91
1.11
Mean3 0.99 1.01 1.01
are not significantly different at the 5% level.
sieve (10-mesh) had approximately the same Kp values as those ground to pass
through a 0.6 or 0.25-mm maximum diameter (30 or 60-mesh) sieve. The Kp
values obtained for each treatment were not different at the 5% level of
probability- While the extent of grinding did not appreciably affect sorption
of acetophenone, it may serve to decrease subsample variability for soil
chemical analysis.
123
-------
6.3.2.3. Organic Matter Removal
Treatment with NaOCl was very effective in oxidizing organic matter
for the 14 samples studied (Table 6.12). Analysis indicated approximately
TABLE 6.12. ORGANIC CARBON CONTENTS AND MODIFIED FREUNDLICH
PARTITION COEFFICIENTS (Kp, l/n=l) BEFORE AND AFTER ORGANIC
MATTER REMOVAL, AND EXPANDABLE (2:1) CLAY MATERIAL
IN SOIL AND SEDIMENT SAMPLES.
Sample
4
5
6
8
9
14
15
18
20
21
22
23
26
B2
Organic
C»\
v/°>
before
treatment
2.07
2.28
0.72
0.15
0.11
0.48
0.95
0.66
1.30
1.88
1.67
2.38
1.48
1.21
Carbon
1
after
treatment
0.11
0.04
0.07
0.02
0.03
0.04
0.04
0.03
0.02
0.06
0.09
0.03
0.11
0.01
2:1
Kp expandable
clay
before
treatment
0.89
0.56
0.68
0.07
0.09
0.12
0.27
0.30
0.29
0.85
0.53
0.68
0.66
0.44
after
treatment
0.65
0.49
0.94
0.28
0.31
0.28
0.29
0.33
0.25
0.33
0.30
0.44
0.29
0.17
40
26
61
6
16
14
10
30
22
3
15
58
37
2
95% reduction in organic carbon content for most samples, and no sample
contained more than 0.11% organic carbon after treatment. Organic matter
removal followed by calcium saturation of the samples decreased Kp values for
samples initially containing more than 1% organic carbon and increased Kp
values for samples containing less than 1% organic carbon before treatment.
124
-------
Kp values for samples containing large amounts of organic carbon might be
expected to decrease .upon treatment since organic carbon has been shown to
be the major factor controlling sorption of acetophenone (16). The increase
in adsorption of acetophenone by samples containing less than 1% organic
carbon initially may be partially accounted for by the fact that samples were
calcium-saturated after treatment with NaOCl. Calcium had been added to
flocculate the soils and sediments insuring a clear solution phase for
isotherm analysis. Preliminary data in our laboratory indicate that sorption
of acetophenone by otherwise untreated samples increases when samples are
calcium-saturated.
Since organic carbon has been shown to be the major factor affecting
acetophenone adsorption (16 ), other soil properties may become significant
with organic matter removal. The Kp values were not correlated with the
remaining organic matter after NaOCl treatment. The data showed that
correlation of Kp with 2:1 expandable clay mineral content was 0.77 and
significant at the 1% level of probability when samples had been subjected to
organic matter removal. A plot of these data is shown in Figure 6.2. The
following regression model was developed using Kp as a dependent variable and
2:1 expanding clay content (Y) as an independent variable.
Kp = 0.19 + 0.008 Y (6-1)
Other workers have reported that swelling clay minerals are important
constituents for sorption of pesticides (12,72,73,75). The correlation
of Kp with total clay was also significant (0.59) but at the 5% level largely
because % total clay is correlated, as expected, with swelling clay. However,
clay type is extremely important, as exemplified by samples 6 and 14. These
two samples contain approximately the same amount of clay (total) but sample
6 (Kp = 0.94) contains more than 4 times as much montmorillonite as sample 14
(Kp = 0.28) and had a Kp more than 3 times that of sample 14.
125
-------
0 20 40 60 80
%CLAY(2:l EXPANDING)
FIGURE 6.2. COMPARISON OF THE LINEAR PARTITION COEFFICIENTS (Kp) FOR THE
SORPTION OF ACETOPHENONE RY SOIL AND SEDIMENT SAMPLES AND THE
PERCENT CLAY IN THE SAMPLES AFTER ORGANIC MATTER OXIDATION
126
-------
SECTION 7
LITERATURE CITED
1. Lowell, P. S., and K. Schwitzgebel. 1974. Potential byproducts formed
from minor and trace components in coal liquefaction processes. In
Symposium Proceedings: Environmental Aspects of Fuel Conversion Tech-
nology. Report No. EPA 650/2-74-118. Washington, DC: Office of Research
and Development, U.S. Environmental Protection Agency.
2. Forney, A. J., W. P. Haynes, S, J. Gasior, G. E. Johnson and J. P. Strakey,
Jr. 1974. Analyses of Tars, Chars, Gases, and Water Found in Effluents
from the Synthane Processes. Technical Progess Report 76. Washington,
DC: Bureau of Mines, U.S. Department of the Interior.
3. Schmidt, C. E., A. G. Sharkey, Jr., and R. A. Friedel. 1974. Mass
Spectrometric Analysis of Product Water from Coal Gasification. Technical
Progess Report 86. Washington, DC: Bureau of Mines, U.S. Department of
the Interior.
4. Magee, E. M., R. R. Bertrand and C. E. Jahnig. 1976. Environmental
impact and R & D needs in coal conversion. In Symposium Proceedings:
Environmental Aspects of Fuel Conversion Technology,11. Report No. EPA
600/2-76-149. Washington, DC: Office of Research and Development, U.S.
Environmental Protection Agency.
5. Hutchinson, T. C., J. A. Hellebust, D. Mackay, D. Tarn and P. Kauss. 1979.
Relationship of hydrocarbon solubility to toxicity in algae and cellular
membrane effects. In Proc. Joint Conf. Prevention and Control of Oil
Spills, Los Angeles, CA.
6. Lindquist, A. E. 1977. Siting Potential for Coal Gasification Plants in
the United States. Information Circular, 1C 8735. Washington, DC:
Bureau of Mines, U.S. Department of the Interior.
7. Weber, W. J., Jr. 1972. Physiaochemical Processes for Water Quality
Control. New York: Wiley-Interscience. 640 p.
8. Zettlemoyer, A. C., and F. J. Micale. 1971. Solution adsorption
thermodynamics for organics on surfaces. In Organic Compounds in Aquatic
Environments, ed. S. D. Faust and J. V. Hunter, pp. 165-185. New York:
Marcel Dekker, Inc.
127
-------
9- Gustafson, R. L., and J. Paleos. 1971. Interactions responsible for
the selective adsorption of organics on organic surfaces. In Organic
Compounds in Aquatic Environments, ed. S. D. Faust and J. V. Hunter, pp.
213-237. New York: Marcel Dekker, Inc.
10. Huang, P. M., T. S. C. Wang, M. K. Wang, M. H. Wu and N. W. Shu. 1977.
Retention of phenolic acids by noncrystalline hydroxy-aluminum and -iron
compounds and clay minerals of soils. Soil Sci. 123:213-219.
11. Hamaker, J. W., and J. M. Thompson. 1972. Adsorption. In Organic
Chemicals in the Soil Environment, ed. C. A. I. Goring and J. W. Hamaker,
pp. 49-143. New York: Marcel Dekker, Inc.
12. Weber, T. B., P. W. Perry and R. P. Upchurch. 1965. The influence of
temperature and time on the adsorption of paraquat, diquat, 2,4-D and
prometone by clays, charcoal, and an anion-exchange resin. Soil Sci.
Soc. Am. Proc. 29:678-688.
13. Zierath, D. L., J. J. Hassett, W. L. Banwart, J. C. Means and S. G. Wood.
1980. Sorption of benzidine by sediments and soils. Soil Sci. (in
press).
14. Horvath, C. , and W. Melander. 1978. Reversed-phase chromatography and
the hydrophobic effect. Am. Lab., October, pp. 17-36.
15. Karickhoff, S. W., D. S. Brown and T. A. Scott. 1979. Sorption of
hydrophobic pollutants on natural sediments. Water Res. 13:241-248.
16. Khan, A., J. J. Hassett, W. L. Banwart, J. C. Means and S. G. Wood. 1979.
Sorption of acetophenone by sediments and soils. Soil Sci. 128:297-302.
17. Hassett, J. J., J. C. Means, W. L. Banwart, S. G. Wood, S. Ali and A.
Khan. 1980. Sorption of dibenzothiophene by soils and sediments. J.
Environ. Qual. (in press).
18. Means, J. C., J. J. Hassett, S. G. Wood and W. L. Banwart. 1979.
Sorption properties of energy-related pollutants and sediments. In
Polynuclear Aromatic Hydrocarbons, ed. P. W. Jones and P. Leber, pp. 327-
340. Ann Arbor, MI: Ann Arbor Science Publ., Inc.
19. Osgerby, J. M. 1970. Sorption of un-ionized pesticides by soils. In
Sorption and Transport Processes in Soils, pp. 63-78. Monograph 37.
London: Society of Chemical Industry.
20. Gillingham, D., and D. Heien. 1971. Regression thru the origin. Am.
Stat. 25:54-55.
21. Wahid, P. A., and N. Sethunathan. 1978. Sorption-desorption of
parathion in soils. J. Agric. Food Chem. 26:101-105.
128
-------
22. Chiou, C. T., L. J. Peters and V. H. Freed. 1979. A physical concept
of soil-water equilibria for nonionic organic compounds. Science 206:
831-832.
23. Stevenson, F. J. 1972. Organic matter reactions involving herbicides
in soil. J. Environ. Qual. 1:333-343.
24. Helling, C. S., and B. C. Turner. 1968. Pesticide mobility: Deter-
mination by soil thin-layer chromatography. Science 162:562-563.
25. Shin, Y.-O., J. J. Chodan and A. R. Wolcott. 1970. Adsorption of DDT
by soils, soil fractions, and biological methods. J. Agric. Food Chem.
13:1129-1133.
26. Helling, C. S. 1971. Pesticide mobility in soils. I. Parameters of
soil thin-layer chromatography. Soil Sci. Soc. Am. Proc. 35:732-737.
27. U.S. Environmental Protection Agency (Washington, DC). 1973. List of
toxic [water] pollutants. Fed. Register 38:24342-24344.
28. U.S. Department of Labor (Washington, DC). 1974. Carcinogen. Fed.
Register 39:3756-3797.
29. Clayson, D. B. 1976. Occupational bladder cancer. Prev. Med. 5:228-
244.
30. Haley, T. J. 1975. Benzidine revisited. Review of the literature and
problems with the use of benzidine and its congeners. Clin. Toxicol.
8:13-42.
31. Korenman, I. M., and B. A. Nikolaev. 1974. Determination of the
protonation constants of weak diacidic bases by an extraction method.
Zh. Fiz. Khim. 48:2545-2549 (Russ.).
32. Solomon, D. H. , B. C. Loft and J. D. Swift. 1968. Reactions catalyzed
by minerals. IV. The mechanism of the benzidine blue reaction on
silicate minerals. Clay Miner. 7:389-397.
33. Theng, B. K. G. 1971. Mechanisms of formation of colored clay-organic
complexes. A review. Clays Clay Miner. 19:383-390.
34. Tennakoon, D. T. B., J. M. Thomas, M. J. Tricker and J. 0. Williams.
1974. Surface and interclate chemistry of layered silicates. Part I.
General introduction and the uptake of benzidine and related organic
molecules by montmorillonite. J. Chem. Soa.3 Dalton Trans. (20):2207-2211.
35. Tennakoon, D. T. B., J. M. Thomas and M. J. Tricker. 1974. Surface and
intercalate chemistry of layered silicates. Part II. An iron-57
MBssbauer study of the role of lattice-substituted iron in the benzidine
blue reaction of montmorillonite. J. Chem. Soo, y Dalton Trans. (20):2211-
2215.
129
-------
36. Tennakoon, D. T. B., and M. J. Tricker. 1975. Surface and intercalate
chemistry of layered silicates. Part V. Infrared, ultraviolet, and
visible spectroscopic studies of benzidine-montmorillonite and related
systems. J. Chem. Soc.} Dalton Trans. (18):1802-1806.
37. Blumer, M. 1976. Polycyclic aromatic compounds in nature. Sci. Am.
234:35-45.
38. MacKenzie, M. J., and J. V. Hunter. 1979. Sources and fates of aro-
matic compounds in urban stormwater runoff. Env. Sci. Technol. 13:
179-183.
39. Briggs, G. G. 1973. A simple relationship between soil adsorption of
organic chemicals and their octanol/water partition coefficients. Proc.
7th British Insecticide Fungicide Conf.3 pp. 475-478.
40. Hilton, B. D., and R. D. O'Brien. 1964. A simple technique for triti-
ation of aromatic insecticides. J. Agric. Food Chem. 12:236-239.
41. Lu, P.-Y., R. L. Metcalf amd E. M. Carlson. 1978. Environmental fate
of five radiolabeled coal conversion by-products evaluated in a labora-
tory model ecosystem. Environ. Health Perspect. 24:201-208.
42. Leo, A., C. Hansch and D. Elkins. 1971. Partition coefficients and
their uses. Chem. Rev. 71:525-616.
43. Chiou, C. T., V. H. Freed, D. W. Schmedding and R. L. Kohnert. 1977.
Partition coefficient and bioaccumulation of selected organic chemicals.
Environ. Soi. Technol. 11:475-478.
44. Karickhoff, S. W., and D. S. Brown. 1979. Determination of octanol/
water distribution coefficients, water solubilities, and sediment/water
partition coefficients for hydrophobic organic pollutants. Report No.
EPA 600/4-79-032. Athens, GA: Office of Research and Development, U.S.
Environmental Protection Agency.
45. Haque, R., and D. Schmedding. 1975. A method of measuring the water
solubility of hydrophobic chemicals: Solubility of five polychlorinated
biphenyls. Bull. Environ. Contam. Toxicol. 14:13-18.
46. Mackay, D., and W. Y. Shiu. 1977. Aqueous solubility of polynuclear
aromatic hydrocarbons. J. Chem. Engin. Data 22:399-402.
47. Peech, M. 1965. Hydrogen-ion activity. In Methods of Soil Analysis*
Agronomy 9(2), ed. C. A. Black, pp. 914-926. Madison, WI: American
Society of Agronomy.
48. Banwart, W. L., and J. J. Hassett. 1976. Laboratory Introduction to
Soil Science. Champaign, IL: Stipes Publishing Co. 118 p.
130
-------
49. Bremner, J. M. 1965. Total nitrogen. In Methods of Soil Analysis,
Agronomy 9(2), ed. C. A. Black, pp. 1149-1178. Madison, WI: American
Society of Agronomy.
50. Allison, L. E. 1965. Organic carbon. In Methods of Soil Analysis,
Agronomy 9(2), ed. C. A. Black, pp. 1367-1378. Madison, WI: American
Society of Agronomy.
51. Day, P. R. 1965. Particle fractionation and particle size analysis.
In Methods of Soil Analysis, Agronomy 9(1), ed. C. A. Black, pp. 545-567.
Madison, WI: American Society of Agronomy.
52. Kilmer, V. J., and L. T. Alexander. 1949. Methods of making mechanical
analyses of soils. Soil Sci. 68:15-24.
53. Anderson, J. U. 1961. An improved pretreatment for mineralogical anal-
ysis of samples containing organic matter. Clays Clay Miner. 10:380-388.
54. Mehra, 0. P. , and M. L. Jackson. 1958. Iron oxide removal from soils
and clays by a dithionate-citrate system buffered with sodium bicar-
bonate. Clays Clay Miner. 5:317-327.
55. Theisen, A. A., and M. E. Harward. 1962. A paste method for preparation
of slides for clay mineral identification by x-ray diffraction. Soil
Sei. SOG. Am. Proa. 26:90-91.
56. Brown, C. Q. 1959. Clay mineral relations in two tributary basins
within the York River tributary basin. Southeastern Geol. 1:95-104.
57. Lucas, J. 1962. The transformation of clay minerals during sedimenta-
tion: Studies of Triassic clays. Mem. Serv. Carte Geol. Alsace
Lorraine 23:1-202 (Fr.). Washington, DC: (Transl. and publ. for) U.S.
Department of Agriculture and National Science Foundation. 21 p.
58. Jackson, M. L. 1965. Free oxides, hydroxides, and amorphous alumino-
silicates. In Methods of Soil Analysis, Agronomy 9(1), ed. C. A. Black,
pp. 578-603. Madison, WI: American Society of Agronomy.
59. Khan, A., and W. L. Banwart. 1979. Effect of incubation and microbial
inhibition at field moisture capacity on changes in DTPA-extractable Fe,
Zn, and Cu in soils of varying pH. Comm. Soil Sci. Plant Anal. 10:
613-622.
60. Khan, A., and P. N. Soltanpour. 1978. Effect of wetting and drying on
DTPA-extractable Fe, Zn, Mn, and Cu in soils. Comm. Soil Sci. Plant
Anal. 9:193-202.
61. Molloy, M. G., and R. B. Lockman. 1979. Soil analysis as affected by
drying temperatures. Comm. Soil Sci. Plant Anal. 10:545-550.
131
-------
62. Sertsu, S. M., and P. A. Sanchez. 1978. Effects of heating on some
changes in soil properties in relation to an Ethiopian land management
practice. Soil Sci. Soo. Am. J. 42:940-944.
63. Thien, S. J., D. A. Whitney and D. A. Karlen. 1978. Effect of micro-
wave radiation drying on soil chemical and mineralogical analysis.
Cam. Soil Sci. Plant Anal. 9:231-241.
64. Soltanpour, P. N., A. Khan and A. P. Schwab. 1979. Effect of grinding
variables on the NHijHCOa-DTPA soil test values for Fe, Zn, Mn, Cu, P,
and K. Conm. Soil Sci. plant Anal. 10:903-909.
65. Soltanpour, P. N., A. Khan and W. L. Lindsay. 1976. Factors affecting
DTPA-extractable Zn, Fe, Mn, and Cu from soils. Conm. Soil Sci. Plant
Anal. 7:797-821.
66. Deli, J., and G. F. Warren. 1971. Adsorption, desorption, and leaching
of diphenamid [N,N-dimethyl-2,2-diphenylacetamide] in soils. Weed Sci.
19:67-69.
67. Doherty, P. J., and G. F. Warren. 1969. Adsorption of four herbicides
by different types of organic matter and a bentonite clay. Weed Res. 9:
20-26.
68. Grover, R. 1971. Adsorption of picloram by soil colloids and various
other adsorbents. Weed Sci. 19:417-418.
69. Hance, R. J. 1965. The adsorption of urea and some of its derivatives
by a variety of soils. Weed Res. 5:98-107.
70. Hance, R. J. 1965. Relation between the adsorption of diuron and the
nature of the adsorbent. Weed Res. 5:108-114.
71. Upchurch, R. P., and W. C. Pierce. 1958. The leaching of monuron from
Lakeland sand soil. II. The effect of soil temperature, organic matter,
soil moisture, and amount of herbicide. Weeds 6:24-33.
72. Coats, G. E., H. H. Funderburk, Jr., J. M. Lawrence and D. E. Davis.
1966. Factors affecting persistence and inactivation of diquat and
paraquat. Weed Res. 6:58-66.
73. Weber, J. B., and D. C. Scott. 1966. Availability of a cationic herbi-
cide adsorbed on clay minerals to cucumber seedlings. Science 152:
1400-1402.
74. Weed, S. B., and J. B. Weber. 1968. The effect of adsorbent charge on
the competitive adsorption of divalent organic cations by layer-silicate
minerals. Am. Mineral. 53:478-489.
132
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/3-80-041
3. RECIPIENT'S ACCESSION1 NO.
. TITLE AND SUBTITLE
Sorption Properties of Sediments and Energy-Related
Pollutants
5. REPORT DATE
1980 issuing date
6. PERFORMING ORGANIZATION CODE
'. AUTHOR(S)
John J. Hassett, Jay C. Means, Wayne L. Banwart, and
Susanne G. Wood
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Agronomy
University of Illinois at Urbana-Champaign
Urbana, Illinois 61801
10. PROGRAM ELEMENT NO.
A1MH1E
11. CONTRACT/GRANT NO.
68-03-2555
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Research Laboratory—Athens
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Georgia 30605
GA
13. TYPE OF REPORT AND PERIOD COVERED
Final, 7/77-12/79
14. SPONSORING AGENCY CODE
EPA/600/01
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report describes the factors that determine the extent of sorption of organ-
ic compounds that are representative of coal conversion waste streams. The compounds,
all radiolabeled, were acetophenone; 1-naphthol; pyrene; 7,12-dimethylbenz(aL)anthra-
cene; 3-methylcholanthrene; dibenz(ci,]i)anthracene; acridine; 2,2'-biquinoline; 13H-
dibenzo(a_,^)carbazole; dibenzothiophene; benzidine; 2-aminoanthracene; 6-aminochrysene;
and anthracene-9-carboxylic acid. Batch equilibrium isotherms were determined for
each compound on 14 sediments and soils that had been collected from the Missouri,
Illinois, Mississippi, and Ohio rivers and their watersheds. Laboratory procedures
for determining octanol-water partition coefficients and water solubilities were
developed and then performed on the compounds.
The sorption constants were correlated with soil and sediment properties and witl
the water solubilities and octanol-water partition coefficients of the compounds. Re-
gression equations were developed that allow prediction of a hydrophobic compound's
linear partition coefficient from knowledge of the compound's octanol-water partition
coefficient or its water solubility and the organic carbon content of the sediment or
soil.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COS AT I Field/Group
Adsorption
Chemical analysis
Coal
Energy
Organic compounds
Sediments
68C
68D
99A
99D
IS. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
CURITY CLASSJT/ll
UNCLASSIFIED
!1. NO. OF PAGES
147
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
133
•Ct U.S. GOVERNMENT PRINTING OFFICE: 1980 -657-146/5634
------- |