REMOTE DETECTION AND PRELIMINARY HAZARD

REMOTE DETECTION AND PRELIMINARY HAZARD EVALUATION OF VOLATILE ORGANIC CONTAMINANTS IN GROUNDWATER

by Donn Louis Marrin

A Dissertation Submitted to the Faculty of the DEPARTMENT OF HYDROLOGY & WATER RESOURCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY WITH A MAJOR IN WATER RESOURCES ADMINISTRATION In the Graduate College THE UNIVERSITY OF ARIZONA

1 984

Copyright 1984 Donn Louis Marrin

THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE

As members of the Final Examination Committee, we certify that we have read the dissertation prepared by entitled

DONN LOUIS

MARRIN

Remote Detection and Preliminary Hazard Evaluation

of Volatile Organic Contaminants in Groundwater

and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of

DOCTOR OF PHILSOPHY in Water Resources Administration

Date

Date

.»(Y

12 Date

/4/2/0

Ot

Date

Date

Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College.

I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement.

I 2-

Date

13 tfly

STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the copyright holder.

SIGNED:

PREFACE

The dissertation addresses two aspects of groundwater contamination by volatile organic chemicals. Chapter I presents a remote detection technique capable of assessing the extent and composition of groundwater plumes. An advantage of this soil gas analysis technique is its ability to quickly and inexpensively define halocarbon/hydrocarbon plumes and thus reduce the health risks from contaminated groundwater supplies. Legislative impetus for such a technique is provided by the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA). CERCLA is administered by the EPA's Office of Emergency and Remedial Response which reacts whenever there is a release of hazardous substances which present a substantial threat to public health. CERCLA and corresponding state laws have created a tremendous need for rapid and accurate methods of subsurface investigation. Chapter II encorporates data on the soil gas behavior of volatile contaminants along with existing research on their retardation, flow, hydrolysis, biodegradation, and potential carcinogenicity in order to generate a hazard evaluation model. The relative hazard indices. presented in Chapter II represent a "predictive" alternative to the

iii

iv conventional "crisis intervention" approach to chemical contamination of groundwater. The model assesses the relative site-specific hazards of petroleum and halogenated hydrocarbons before they are spilled or released. Hazard evaluations based on the physical/chemical properties

of a compound are mandated under the Toxic Substances Control Act of 1976 (TSCA) for all new and existing chemicals. TSCA and similar legislation requires the rapid screening of thousands of compounds.

This dissertation focuses on two of the most critical issues in managing groundwater contamination: (i) assessment of existing problems

via a rapid detection technique and (ii) avoidance of future problems via an effective screening process. Both topics are at the forefront of water resources research. Chapter I consists of the final project

report in the U.S. Environmental Protection Agency.

ACKNOWLEDGEMENTS This research was funded by the U.S. Environmental Protection Agency (Project #CR811018-01-0) as a cooperative agreement between the University of Arizona and the EPA's Robert S. Kerr Environmental Research Laboratory. We thank the following people for their assistance on various aspects of the project: M. Bradley (Project Manager), D. Kreamer (technical expertise), M. Busse (report production/quality assurance), M. Malcomson (analytical chemistry), A. Klein (laboratory work), M. Krotenberg and J. Coffey (field work). We would also like to thank D. Pool (U.S. Geological Survey) for providing geophysical logs, and the Tucson Airport Authority for granting access to the field site. The research in Chapter II was prompted by conversations with a variety of environmental regulators and consultants. Computer work was completed on the University of Arizona's VAX 2 system and was funded by the Department of Hydrology and Water Resources. I would like to thank A. Cotagageorge and L. Laplander for their assistance in preparing the manuscript. Thanks also to M. Bradley who has served as my dissertation director and to G. Thompson who has provided advice on several aspects of the dissertation.

TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS

viii

LIST OF TABLES ABSTRACT



xi

CHAPTER I REMOTE DETECTION OF ORGANIC GROUNDWATER CONTAMINANTS VIA THEIR PRESENCE AND MOVEMENT IN THE UNSATURATED ZONE INTRODUCTION Location



1

1 1 4

METHODS I. II. III. IV. V. VI. VII. VIII.



Shallow Soil Gas Sampling Shallow Soil Gas Transects Vertical Soil/Soil Gas Profiles Horizontal Soil Profiles Analysis of Gas Soil, and Water Samples Characterization of the Porous Media Radioactive Logging of Boreholes Laboratory Sorption Studies

6 6 9 10 12 13 14 16 17



RESULTS AND DISCUSSION I. Shallow Soil Gas II. Shallow Soil Gas Mapping III. Vertical Profiles IV. Soil Sampling V. Vertical Flux Measurements VI. Soil Gas/Groundwater Correlations VII. Partitioning Coefficients



18 18 23 27 43 47 57 60

SUMMARY



65

CHAPTER II PRELIMINARY EVALUATION OF THE HEALTH AND ENVIRONMENTAL HAZARDS ASSOCIATED WITH ORGANIC GROUNDWATER CONTAMINANTS. . INTRODUCTION I. Model Input HYDROCHEMICAL MODEL I. Retardation Factor for Dissolved Flow IL Retardation Factor for Immiscible Flow

67

vi



67 67 68 70 70 74

vii

TABLE OF CONTENTS - Continued Page

III. Volatilization and Diffusion Parameters IV. Hydrolysis and Chemical Oxidation V. Biodegradation



77 78 79

BIOCHEMICAL MODEL I. Assessment of Carcinogenicity H. Aliphatic and Alicyclic Hydrocarbons III. Aromatic Hydrocarbons IV. Halogenated Hydrocarbons V. Haloalkanes VI. Haloalkenes and Halobenzenes RESULTS AND DISCUSSIONS I. Model Output IL Applications



81 81 83 84 85 86 88



89 89 103

APPENDIX A

106

APPENDIX B

109

APPENDIX C

119

REFERENCES

122

LIST OF ILLUSTRATIONS Figure



Page

CHAPTER I 1 Map showing the distribution of TCE in shallow soil gas at Tucson Airport

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100 well-defined correlations between the chemical structure of halocarbons or hydrocarbons and effective diffusion coefficients. Among petroleum hydrocarbons, there is decreasing volatilization or air-water partitioning by compounds of similar molecular weight in the order: alkanes > alkenes > cycloalkanes > alkylbenzenes. Within hydrocarbon classes, there is generally an increase in air-water partitioning and a decrease in diffusion with molecular weight. Figure 8 shows the effect

of increasing alkyl substitution on the diffusion and air-water partitioning of monoaromatic hydrocarbons. The increase in Henry's Law constant with alkyl substitution is primarily due to decreases in aqueous solubility rather than to increase in vapor pressure. Decreases in soil gas diffusion with increasing substitution of alkyl-benzenes reflect increasing molecular weight and molar volume of contaminants. A thorough discussion of the qualitative model used to predict the subsurface hydrolysis and biodegradation of organic contaminants appears in a previous section. No quantitative calculations were associated with the estimation of these two hazard indices, and therefore analysis of model output is unnecessary. Output from the biochemical model is difficult to compare against the existing literature because "degree" of carcinogenicity is not a universal concept. Compounds are more commonly categorized as confirmed human carcinogens, confirmed animal carcinogens, suspected animal carcinogens or mutagens. This type of classification provides no information about the relative carcinogenicity of chemicals, and

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therefore relative potency must be determined from maximum contaminant levels (MCL's) or other health advisories. The relative carcinogenicity of common groundwater contaminants as calculated by the additivity model is presented in Table 1. All the confirmed human carcinogens identified by Kool et al. (1983) which were considered in this model appear as definite carcinogens in the model output. In addition, all compounds in Table 1 (except perchloroethylene) possessing an EPA 10-day health advisory of less than 0.25 ppm have been identified by the model as definite or probable carcinogens. Compounds identified by the model as non-carcinogenic either have a 10-day health advisory of greater than 2.5 ppm or no advisory at all (NRC 1980). Compounds classified as possible carcinogens in Table 1 have a 10-day health advisory between 0.25 and 2.5 ppm. Although relative carcinogenicity is extremely difficult to determine among different chemical groups, the additivity model (Appendix B) produced consistent results which were based entirely on chemical structure. The biochemical mechanism of carcinogenicity was simply assigned on structure-specific basis and was not actually calculated by the model. Nevertheless, the biochemical mechanism is an important hazard index when considering the presence of more than one carcinogen in groundwater. Structurally and biochemically similar carcinogens should be considered as a single chemical group. Current regulations which only consider MCL's for individual compounds probably underestimate the

103 carcinogenic hazard of multiple compounds in water by ignoring additive or synergistic effects.

II. Applications This model was designed as a tool for water resource or environmental decision-makers who are often confronted by problems which demand a broad spectrum of expertise. An advantage of the model is that it requires only a few chemical properties and a rough estimate of site-specific conditions as input. Output can be obtained for either new or existing compounds and for either proposed or existing sites. Klein & Schmidt-Bleek (1982) have identified a shift in environmental legislation from "curative" to "preventative" control of chemicals. Such a shift is evident in TSCA which requires identification of potentially hazardous substances before they are approved instead of

after they pose a threat to human health. The most valuable application of the model is screening new chemicals which are under consideration for EPA's approval. TSCA gives EPA's Office of Toxic Substances Control only 90 days and a few physical/chemical properties to determine whether new compounds should be approved or tested further (Biles 1979). The use of this type of model to screen volatile organic contaminants for their potential effects on groundwater resources would be optimal under such time constraints. Furthermore, industry's major objection to the premarketing notification required under TSCA is disclosure of valuable proprietary information (Biles 1979). For purposes of screening new

104 TABLE I. Classification of the Carcinogenic Potential of Common Groundwater Contaminants Based on the Output of the Structural Additivity Model.

DEFINITELY CARCINOGENIC Benzene





Chloroform

Carbon Tetrachloride



1,2-dibromoethane (EDB) Hexachloroethane

Vinyl Chloride

PROBABLY CARCINOGENIC

1,1-dichloroethane



1,1-dichloroethylene



Hexachlorobenzene

1,1,2-trichloroethane

Trichloroethylene (TCE)

Trichlorobenzene

POSSIBLY CARCINOGENIC

NOT CARCINOGENIC

Toluene

Fluoroalkanes

Xylenes

Chlorofluoroalkanes

1,2-dichloroethane

Aliphatic Hydrocarbons

1,1,1-trichloroethane (TCA)

Alicyclic Hydrocarbons

1,2-dichloroethylene Perchloroethylene (PCE) Chlorobenzene

105

compounds for groundwater contamination potential, the present model requires minimal disclosure of physical properties (density, molecular weight, and boiling point) in addition to the chemical structure. Applications of the model other than screening new chemicals include: (i) determining the relative hazards of a groundwater plume containing a variety of VOC's, (ii) selecting a method of plume delineation for a known contaminant on a site specific basis, and (iii) -

deciding whether solvents/fuels should be stored underground at a

particular site.

APPENDIX A Listing of the 75 volatile organic compounds in eight chemical classes analyzed by the hydrochemical/ biochemical model in this study.

106

107

ALKANES n-Hexane n-Heptane n-Octane n-Nonane Isopentane Isooctane 2-Methylpentane 2-Methylhexane 3-Methylheptane 2,5-Dimethylhexane 2,3-Dimethylbutane 2,4-Dimethylpentane

ALKENES 1-Hexene 2-Pentene 2-Methyl-I-Pentene 3-Methyl-I-Butene Isobutene

CYCLOALKANES Cyclopentane Cyclohexane Methylcyclohexane Methylcyclopentane 1,2-Dimethylcyclohexane 1,4-Dimethylcyclohexane Ethylcyclopentane

ALKYLBENZENES Benzene Toluene p-Xylene Ethylbenzene Propylbenzene Isopropylbenzene

ALKYLBENZENES (cont.) p-Ethyltoluene tert-Butylbenzene 1,2,4-Trimethylbenzene 1,2-Diethylbenzene 1,2,4,5-Tetramethylbenzene

HALOMETHANES Methylene chloride Chloroform Carbon tetrachloride Bromoform Bromomethane Fluorotrichloromethane (F-11) Difluorodichloromethane (F-12) Chloromethane Bromodichloromethane Chlorodibromomethane Iodomethane

HALOETHANES 1,1-Dichloroethane (DCA) 1,2-Dichloroethane 1,1,1-Trichloroethane (TCA) 1,1,2-Trichloroethane 1,1,1,2-Tetrachloroethane(TTCA) 1,1,2,2-Tetrachloroethane Pentachloroethane (PCA) Hexachloroethane (HCA) 1,2-Dibromoethane (ED6) 1,1,2-Trifluorotrichloroethane (F-113) Dichlorotetrafluoroethane (F-114)

108

HALOETHYLENES Vinyl chloride 1,1-Dichloroethylene (DCE) trans-1,2-Dichloroethylene cis-1,2-Dichloroethylene Trichloroethylene (ICE) Perchloroethylene (PCE)

HALOBENZENES Chlorobenzene (MCB) 1,4-Dichlorobenzene (DCB) 1,3-Dichlorobenzene 1,3,5-Trichlorobenzene (TCB) 1,2,3,5-Tetrachlorobenzene Pentachlorobenzene Hexachlorobenzene (HCB) Bromobenzene (MBB) 1,3-Dibromobenzene COBB) Fluorobenzene Iodobenzene 1,4-Bromochlorobenzene

APPENDIX B Computer program (FORTRAN 5) of the hydrochemical/ biochemical model used in this study. The program includes an explanation of input parameters, computer code, and documentation of the eight hazard indices.

109

110 C PROGRAM: EVALUATION OF BIOCHEMICAL AND HYDROCHEMICAL HAZARDS RESULTING C FROM THE RELEASE OF VOLATILE ORGANIC CHEMICALS INTO THE SUBSURFACE AND C GROUNDWATER ENVIRONMENTS. INPUT: CHEMICAL STRUCTURE AND BASIC PHYSICAL C PROPERTIES OF PETROLEUM AND HALOGENATED HYDROCARBONS. OUTPUT: POTENCY C AND METABOLISM OF POTENTIAL CARCINOGENS. RETARDATION FACTORS FOR DISSOLVED C AND IMMISCIBLE CONTAMINANT FLOW. VOLATILIZATION AND DIFFUSION COEFFICIENTS, C HYDROLOSIS HALF—LIFE, AND SOIL BIODEGRADATION POTENTIAL. $ $ $ $ $ $ $

C C C C C

C C C C C C C

C C C C C C C C C C

10

CHARACTER P01*30, MODE*52, BIODEG*50, SPACE*100, NAME*50, OUTPUT*50, TITLE*200 INTEGER HALO,F,CL,BR,I,H,C,CARBON,CLASS,METH,ETH,ETHY,N REAL HA. BEN, HADEN, ANE, TOX. FLOR, LENE, SAND, FINES, POR, VW, OC, RHO, SOL, AQUA, GMW, LSOL, LISOL, LKOW, LKOC, KOC, LG. KP, RFDIS, BP, LNBP, B. LUIS, %/ism M. wc, MW, PERCON, PERWAT, IMMS, SAT, AIR, VAPOR DELTA, CTWO, LEFT, LNVP, HLC, VOL, MR, INCR, VB, CURDIF, DIFCO3 HYDL FS, KF, CEMENT, DEPTH, MIC, LMIC, EVAP, X. CAT, HAT, FAT, CLAT, BRAT, IAT, Y, Z. LOGAQ TITLE='BIOCHEMICAL/HYDROCHEMICAL HAZARD EVALUATION OF VOLATILE ORGANIC CONTAMINANTS IN THE SUBSURFACE ENVIRONMENT' WRITE (54,*) TITLE OUTPUT='OUTPUT DATA:

INPUTTING THE DATA FOR PROGRAM OPERATION: ALL INPUT DATA WILL BE READ FROM

A DATA FILE IN THE FOLLOWING SEQUENCE (NOTE: THE ORDER OF INPUT PARAMETERS MUST BE FOLLOWED EXACTLY AS OUTLINED BELOW). (1) NAME= FULL IUPAC NAME OF CHEMICAL (COMMON NAMES IN PARENTHESIS). (2) CLASS= CLASSIFICATION OF CHEMICAL BASED ON THE FOLLOWING GROUPINGS: (1=NORMAL AND BRANCHED ALKANES. 2=CYCLOALKANES; 3=NONCYCLIC ALKENES; 4=BENZENE AND ALKYL BENZENES; 5=HALOMETHANES; 6=HAL0ETHANES; 7=HAL0ETHYLENES; 8=HALOBENZENES) (3) F= * OF FLUORINE ATOMS (4) CL= * OF CHLORINE ATOMS (5) BR= * OF BROMINE ATOMS (6) I= * OF IODINE ATOMS (7) H= * OF HYDROGEN ATOMS (8) C= * OF CARBON ATOMS (9) CARBON=BONDING AND SUBSTITUTION OF C ATOMS ACCORDING TO CLASS: ***FOR ALKANES (CLASS *1), CARBON= NUMBER OF BRANCHINGS IN MOLECULE ***FOR ALKENES (CLASS *3), CARBON= NUMBER OF OLEFINIC (DOUBLE) BONDS ***FOR HALOCARBONS (CLASS *6 & *7), CARBON= NUMBER OF HALOGENS ON THE FIRST CARBON ATOM (CARBON WITH THE MOST HALOGENS) ***FOR ALL OTHER CLASSES, CARBON=0 (10) AQUA= AQUEOUS SOLUBILITY AT 20 DEGREES (mg/L, ppm, OR g/cubic meter) NOTE: IF AQUEOUS SOLUBILITY IS NOT AVAILABLE, ENTER A ZERO (0) FOR THIS PARAMETER AND IT WILL BE ESTIMATED IN THE PROGRAM (11) VAPOR= VAPOR PRESSURE AT 20 DEGREES (mm Hg) NOTE: IF VAPOR PRESSURE IS NOT AVAILABLE, ENTER A ZERO (0) FOR THIS PARAMETER AND IT WILL BE ESTIMATED IN THE PROGRAM (12) DENS= LIQUID DENSITY AT 20 DEGREES (g/mL OR g/cc) (13) BP= NORMAL SIDLING POINT (degrees Celcius) (14) GMW= GRAM MOLECULAR WEIGHT (g/mol) (15) OC= ORGANIC CARBON CONTENT IN TOP 3 METERS OF SOIL (() (16) POR= AVERAGE TOTAL POROSITY OF THE VADOSE ZONE (%) (17) VW= AVERAGE VOLUMETRIC WATER CONTENT OF VADOSE ZONE (%) (18) CEMENT=DEGREE OF CEMENTATION OF THE POROUS MEDIA/ ENTER 0=NONE, 1=PARTIAL, 2=TOTAL (19) FINES= POROUS MEDIA WITH A GRAIN DIAMETER < 0.125mm (%)

READ (69,222,END=99) NAME



333 $ 444 * 555

111

FORMAT (A50)

222

WRITE (54, 333) NAME FORMAT (A50) READ (69, 41., END=99) CLASS, F. CL, BR, I. H. C. CARBON, AQUA. VAPOR. DENS, BP. GMW, OC PUR, VW, CEMENT, FINES, DEPTH WRITE (54, 444) CLASS. F. CL, BR. I. H. C, CARBON FORMAT ( 1X, 16) WRITE (54, 555) AQUA. VAPOR. DENS, BP, GMW, OC, PUR, VW. CEMENT. FINES, DEPTH FORMAT (1X, F10. 3 ) WRITE (54,*) OUTPUT

C CALCULATE THE CARCINOGENICITY OF PETROLEUM HYDROCARBONS. HALO=F+CL+BR + I 20 IF (CLASS. LE. 3) THEN POT= 'NOT CARCINOGENIC' MODE= 'NA' GO TO 60 ELSE IF (CLASS. EQ. 4. AND. C. EQ. 6) THEN POT= 'DEFINITELY CARCINOGENIC' MODE= 'FORMATION OF STABLE ARENE OXIDES' GO TO 60 ELSE IF (CLASS. EQ. 4. AND. C. GT. 6) THEN POT= 'PROBABLY NOT CARCINOGENIC' MODE= 'FORMAT ION OF UNSTABLE ARENE OXIDES' GO TO 60 END IF C CALCULATE THE CARCINOGENICITY OF HALOBENZENES BASED ON THE NUMBER, POSITION, C AND TYPE OF HALOGEN. IF (CLASS. EQ. S) TI-EN HA=((I$0.5)+CL+(BR*3)4.(F$0.2))/(6-H) MODE= 'FORMATION OF UNSTABLE ARENE OX IDES' ELSE GO TO 30 END IF IF (H. GE. 4) THEN BEN=1. 5 ELSE IF (H. EQ. 3) THEN BEN=3. 0 ELSE IF (H. EQ. 0) THEN BEN=4. 0 ELSE BEN=2.5 END IF HABEN=HA*BEN IF (HABEN. GE. 4) THEN POT= 'DEFINITELY CARCINOGENIC MODE= 'FORMATION OF STABLE ARENE OXIDES' ELSE IF (4. 0. GT. HADEN. AND. HABEN. GE. 2. 5) THEN POT= 'PROBABLY CARCINOGENIC' ELSE IF (2.5. GT. HABEN. AND. HABEN. GE. 1.0) THEN POT= 'PROBABLY NOT CARCINOGENIC' ELSE POT= 'NOT CARCINOGENIC' MODE= 'NA' END IF GO TO 60 '

C CALCULATE THE CARCINOGENICITY OF HALOMETHANES BASED ON THE NUMBER AND TYPE C HALOGEN SUBSTITUTIONS. F ATOMS REDUCE CARCINOGENICITY OF COMPOUNDS. IF (CLASS.EQ.5) THEN 30 ANE=( (BR*3)+ ( I$0. 5)+CL)/ (HALO-F)

112 MODE= 'FORMATION OF FREE RADICALS AND CARBONYL HALIDES'

ELSE GO TO 40 END IF IF (H. EQ. 0) THEN METH=5

ELSE IF (H. EG. 1) THEN METH=4

ELSE IF (H. EQ. 2) THEN METH=3

ELSE METH=1 ENDIF

IF (F. GE. 3) THEN FLOR =O. 01 ELSE IF (F. EQ. 2) THEN FLOR =O. 05 ELSE IF (F. EQ. 1) THEN FLOR =O. 1 ELSE FLOR =1. 0

END IF TOX=METH*ANE*FLOR IF ( TOX. GE. 5 ) THEN

POT= DEFINITELY CARCINOGENIC' ELSE IF (5. GT. TO X. AND. TO X . GE. 3) THEN POT= 'PROBABLY CARCINOGENIC' ELSE IF (3. GT. TO X. AND. TO X. GE. 1. 0 ) THEN POT= 'PROBABLY NOT CARCINOGENIC' ELSE POT= 'NOT CARCINOGENIC' MODE= 'NA END IF CO TO 60 C CALCULATE THE CARCINOGENICITY OF HALOETHANES EXACTLY LIKE HALOMETHANES. IF (CLASS. EQ. 6) THEN 40 ANE=( (BR*3)+( I*0. 5)+CL)/ (HALO-F) MODE= 'FORMATION OF FREE RADICALS AND HALOACETALDEHYDES'

ELSE GO TO 50 END IF IF ( H. EQ. 0) THEN ETH=4

MODE= 'FORMATION OF EPDX I DES VIA PERHALOETHYLENE SPECIES ELSE IF (H. EG. 1 ) THEN

'

ETH=4

MODE= 'FORMATION OF EPDX I DES VIA TR I HALOE THYLENE SPECIES' ELSE IF (H. EQ. 2. OR. H. EQ. 3) THEN ETH=3 IF ( CARBON. EQ. 3) THEN ETH=2

END IF ELSE IF (H. EQ. 4. AND. CARBON. EQ. 2 ) THEN ETH=3

ELSE IF (H. EQ. 4. AND. CARBON. EQ. 1) THEN ETH=2

ELSE ETH=1

END IF IF (F. GE. 5) THEN FLOR =O. 01 ELSE IF (5. GT. F. AND. F. GE. 3 ) THEN FLOR =O. 1

ELSE IF (3. GT. F. AND. F. GE. 1) THEN

113

FLOR =O. 5 ELSE FLOR =1. 0 END IF TOX=ETH*ANE*FLOR IF ( TOX. GE. 4 ) THEN POT= 'DEFINITELY CARCINOGENIC' ELSE IF (4. GT. TOX. AND. TOX. GE. 2. 5 ) THEN POT= PROBABLY CARCINOGENIC' ELSE IF (2. 5. OT. TOX. AND. TOX. GE. 1.0) THEN POT= 'PROBABLY NOT CARCINOGENIC' ELSE POT= 'NOT CARCINOGENIC MODE= 'NA' END IF GO TO 60 '

C CALCULATE CARCINOGENICITY OF HALOETHYLENES BASED ON NUMBER/TYPE OF HALOGENS IF (CLASS. EG 7) THEN 50 LENE= ( (3*BR ) +CL+ (0. 5*I )4. (0. 2*F) ) /HALO MODE= 'FORMAT ION OF EPDXI DES AND CYSTEINE CONJUGATES' END I F IF (H. EQ. 0) THEN ETHY=1 ELSE IF ( (H. EQ. 2. AND. CARBON. EQ. 2). OR. (H. EQ. 1 ) ) THEN ETHY=2 ELSE IF (H. EQ. 2. AND. CARBON. EQ. 1) THEN ETHY=1 ELSE ETHY=3 END IF TOX=ETHY*LENE IF ( TOX. GE 3) THEN POT= 'DEFINITELY CARC INOGENIC ELSE IF (3. GT. TO X. AND. TO X. GE. 2) THEN POT= `PROBABLY CARCINOGENIC' ELSE IF (2. GT. TO X. AND. TO X. GE. 1) THEN POT= 'PROBABLY NOT CARCINOGENIC' ELSE POT= 'NOT CARCINOGENIC' MODE= 'NA' ENDIF POT WRITE (54,*) 'CARCINOGENIC POTENTIAL= 60 WRITE (54,*) 'BIOCHEMICAL MECHANISM= MODE C C C C C C C

CALCULATE THE RETARDATION FACTOR (WATER VELOCITY/CONTAMINANTVELOCITY ) FOR THE CONTAMINANT IN DISSOLVED FLOW. THE SOIL ORGANICS-WATER PARTITIONING COEFFICIENT (KOC ) AND LOG OCTANOL-WATER PARTITIONING COEFFICIENT (LKOW) MUST BE ESTIMATED FROM THE AQUEOUS SOLUBILITY. THE SOIL BULK DENSITY (RHO) IS ESTIMATED FROM THE APPROXIMATE SAND/FINES COMPOSITION OF THE MEDIA. THE ORGANIC CARBON CONTENT OF THE SOIL (OC) MUST EXCEED O. 1% FOR THE COMPOUND TO PARTITION INTO THE ORGANIC PHASE. FINES=FINES/100 SAND=1-F INES POR=POR/100 VW=VW/100 IF ( OC. LT. O. 1) THEN OC=0 ELSE OC=OC /100 END IF IF (SAND. GE. 0. 67 ) THEN

RHO=1.45

114

ELSE IF (0. 67. GT. SAND. AND. SAND. GE. 0. 34) THEN RHO=1. 32 ELSE RHO=1. 20 ENDIF C IF THE AQUEOUS SOLUBILITY (AQUA) 20 DEGREES IS NOT AVAILABLE, THEN C ESTIMATE IT FROM THE CHEMICAL STRUCTURE OF THE CONTAMINANT. IF (AQUA. GT. 0) THEN GO TO 65 ENDIF IF (CLASS. EQ. 1. OR. CLASS. EQ. 3) THEN X=1. 5 ELSE IF (CLASS. EQ. 2) THEN X=0. 35 ELSE IF (CLASS. EQ. 4. OR. CLASS. EQ. 8) THEN X=0. 5 ELSE IF (H. EQ. 0) THEN IF (CLASS. EQ. 7. AND. F. EQ. 0) THEN X=0. 9 ELSE IF (CLASS. EQ. 5. OR. CLASS. EQ. 6) THEN X=1. 25 END IF ELSE IF ( (CLASS. EQ. 5. OR. CLASS. EQ. 6). AND. (F. EQ. 0) ) THEN X=0. ELSE X=0. 5 ENDIF CAT=0. 25 HAT=0. 12 IF (CLASS. EQ. 7. OR. CLASS. EQ. 8) THEN FAT=0. 19 CLAT=0. 67 BRAT=0. 79 IAT=1. 12 ELSE FAT=0. 28 CLAT=0. 37 BRAT=0. 49 IAT=0. 82 END IF IF (CLASS. EQ. 3. AND. CARBON. EQ. 1) THEN 2=-0. 35 ELSE IF (CLASS. EQ. 3. AND. CARBON. GT. 1) THEN 2=-0. 55 ELSE IF (CLASS. EQ. 1. AND. CARBON. GT. 0) THEN 2=-0. 1 ELSE IF (CLASS. EQ. 5. AND. H. GE. 1) THEN Z-0.3 ELSE IF (CLASS. EQ. 6) THEN IF (HALO. EQ. 6) THEN Z=D ELSE IF (HALO. EQ. 3. AND. CARBON. EQ. 3) THEN 2=0 ELSE 2=-0. 3 END IF ELSE 2=0 END IF Y=(C*CAT)+(H*HAT)+(F*FAT )+(CL*CLAT)+CER*BRAT)+(I*IAT )

115

LOGAQ=-1*(X+V+Z

AQUA=(10**LOGAQ)*1.0E+06 65

SOL=AQUA/(GMW*1000) LSOL=LOG10(SOL) L/SOL=LOG10(1/SOL) MIC=(AQUA*1000)/GMW LMIC=LOG10(MIC) IF (CLASS.LE.2) THEN LKOW=0.808*(LISOL-0.248) ELSE IF (CLASS. E0.3) THEN LKOW=0.773*(LISOL+0.248) ELSE IF (CLASS.E0.4) THEN .LKOW=1.004*(LISOL+0.339) ELSE IF (CLASS.EQ.8) THEN LKOW=1.013*(LSOL-0.4803) ENDIF IF (CLASS.LE.3) THEN LKOC=LKOW-0.21 KOC=10**LKOC ELSE IF (4.EQ.CLASS.OR.CLASS.E0.8) THEN LKOC=0.49+(LKOW*0.72) KOC=10**LKOC ELSE L0=4. 04—(0. 557*LMIC KOC= ( 10**LG) /1. 724 END IF KP= ( SAND*0. 2*OC*KOC )+(FINES*OC*KOC RFDIS=1+( (KP*R1-10 ) /VW ? WRITE (54,*) RETARDATION FACTOR FOR DISSOLVED FLOW (dimentionless)= $ RFD'S

C C C C C C

CALCULATE THE RETARDATION FACTOR (WATER HYDRAULIC CONDUCTIVITY/CONTAMINANT HYDRAULIC CONDUCTIVITY) FOR IMMISCIBLE FLOW. VISCOSITY IS ESTIMATED FROM PHYSICAL PROPERTIES OF THE CONTAMINANT. IF T1.E NORMAL BOILING POINT IS LESS THAN 20 DEGREES (C), THEN THE COMPOUND IS A GAS — NO LIQUID VISCOSITY. ASSUMPTIONS: WATER IS THE WETTING FLUID AND FLOW FOR BOTH LIQUIDS IS IS SATURATED — ASSUMPTIONS APPLY TO THIS PARAMETER ONLY! ! ! BP=BP+273 LNBP =LOG (BP) FS=F/(HALO+H IF (CLASS. EQ. 2. OR. FS. EQ. I) THEN KF=1. 00 ELSE IF( (CLASS. EQ. 4. AND. C. EQ. 6). OR. (CLASS. EQ. 1. AND. CARBON. EQ. 0) ? $ THEN KF=1. 00 ELSE IF ( (CLASS. EQ. 4. AND. C. GT. 6) . OR. (CLASS. EQ. 1. AND. CARBON. GT. 0) . $ THEN KF=0. 99 ELSE IF (CLASS. EQ. 3. OR. H. EQ. 0) THEN KF=1. 01 ELSE IF (HALO. EQ. 1) THEN IF (C. EQ. 1. AND. CL. Efl. 1) THEN KF=1. 05 ELSE IF ((C. EQ. I. AND. BR. EQ. 1 ). OR. (C. GT. 1. AND CL. EQ. 1 ) ) THEN KF=1. 04 ELSE IF ( (C. EQ. 1. AND. I. EQ. 1). OR. (C. GT. 1. AND. BR. EQ. 1) ? THEN KF=1. 03 ELSE IF (C. GT. 1. AND. I. EQ. 1) THEN KF=1. 02 ELSE .

KF=1. 06

ENDIF

ELSE KF=1. 06 ENDIF

IF (VW. GT. POR ) THEN AIR=0 SAT=1

ELSE AIR =POR-VW SAT=VW/P OR END IF IF (BP. LE. 293) THEN WRITE (54,*) 'NO IMMISCIBLE FLOW/ GAS AT 20 DEGREES (C ) ' GO TO 70 ELSE IF (SAT. EQ. 1) THEN WRITE ( 54, * ) 'NO IMMISCIBLE FLOW/ WATER-SATURATED MEDIA GO TO 70 END IF IF (CLASS. LE. 3) TPEN N=8

ELSE N=5

END IF IF (CLASS. EG. 2. AND. C. EQ. 6) THEN LNLB=-0. 916

ELSE IF (CLASS. EQ. 4. AND. C. EQ. 6) THEN LNLB=-1. 204

ELSE LNLB=-1. 609

END 1F B=(1/N)*( (KF*BP* ( 8. 75+ (1 . 987*LNBP ) ) )- (1. 9137*293) ) LVIS=LNLB+(B*(1/293-1/BP ) ) VISC 0=2. 718**LVIS IF (CEMENT. EQ. 2) THEN M=2. 0

ELSE IF (CEMENT. EQ. 1) THEN M=1. 65

ELSE P1=1. 3

END IF WC=SAT MW= ( 2*M ) - (M*WC ) PERCON=( 1-WC )**( 1. 5*M-0. 5) PERWAT=( (WC*POR )**( 1. 5*MW-0. 5) ) / (POR**( 1. 5*M-0. 5) ) IMMS=(VISCO*PERWAT) / (PERCON*DENS ) WRITE ( 54, * ) 'RETARDATION FACTOR FOR IMMISCIBLE FLOW ( d men t i on 1 ess ) = $ MPG C C C C 70

CALCULATE THE VOLATILIZATION POTENTIAL OF CONTAMINANTS. VOLATILIZATION IS A FUNCTION OF HENRY'S LAW CONSTANT (HLC ) MODIFIED BY AIR POROSITY (AIR), DEGREE OF SATURATION (SAT), AND THE WATER-SOIL ORGANICS PARTITIONING COEFFICIENT (KP ) . VAPOR PRESSURE MAY BE ESTIMATED BY PROGRAM. IF (VAPOR. EQ. 0) THEN DELTA 4(F*(8. 75+( 1. 987*LN5P) ) -

CTWO= (0. 19*BP )-18 LEFT=CDELTA* ( (BP-CTWO)**2) )/ (BP*1. 9274) LNvP=LEFT*( 1 / (BP-CTWO)-1/ (293-CTWO) ) VAPOR=(2. 718**LNVP)*760

END IF

116

HLC=VAPORRSOL*1000 )



VOL= HLC WRITE (54, *) 'SUBSURFACE VOLATILIZATION (mm Hg*c ubic met er/mol )= $ VOL C CALCULATE THE DIFFUSION COEFFICIENT (DIFCO) BASED ON THE MOLECULAR WEIGHT C (GMW), AIR POROSITY (AIR), AND CHEMICAL STRUCTURE (I NCR. VB). DIFFUSION C COEFFICIENT IS A MEASURE OF HOW FAST THE CONTAMINANT MOVES IN THE SOIL C GAS, WHILE THE VOLATILIZATION CONSTANT ESTIMATES GAS—WATER PARTITIONING. MR= ( 28. 97+GMW ) / ( 28. 97*0MW) INCR=(C*14. 8 )+(H*3. 7 )+(CL*24. 6)+ (BR*27. 0 )+(F*8. 7 )+(I*37. 0) IF (CLASS. EQ. 4. OR. CLASS. EQ. 8) THEN VB= ( INCR-15. 0 )*O. 875 ELSE VB=INCR*0. 875 END IF CURD IF=( 20. 75*SQRT(MR ) ) / ( (2. 716+ (VB**0. 333) )**2) DIFC 0=CCURDI F*0. 66*A IR )*3600 WRITE (54,*) 'SOIL GAS DIFFUSION COEFFICIENT (square cm/heur )=', DIFCO C CALCULATE THE HYDROLYSIS HALF—LIFE FOR HALOALKANES BASED ON THE NUMBER AND C TYPE OF HALOGEN SUBSTITUENTS. HYDROLYSIS OF OTHER CONTAMINANT CLASSES CON— C SIDERED IN THIS MODEL IS EITHER NON—EXISTENT OR TOO SLOW TO BE SIGNIFICANT.

IF (5. GT. CLASS. OR. CLASS. GT. 6 ) THEN WRITE ( 54, * ) 'SUBSURFACE HYDROLYSIS (day s /ha If-1 i fe ) = NONE' GO TO 80

$

END IF IF (CLASS. EQ. 6) THEN IF (HALO. EQ. 1. AND. F. EG. 1 ) THEN HYDL=7 ELSE IF (HALO. EQ. 1. AND. F. EQ. 0) THEN HYDL=0. 11 ELSE IF (HALO. GT. 1) THEN WRITE (54,*) 'SUBSURFACE HYDROLYSIS (days/half—life) NONE' GO TO 80 END IF END IF IF (CLASS. EQ. 5. AND. HALO. EQ. 1) THEN IF (F. EQ. 1) THEN HYDL=30 ELSE IF (CL. EQ. 1) THEN HYDL=0. 93 ELSE IF (BR. EQ. 1) THEN HYDL=0. 05 ELSE HYDL =O. 30 END I F ELSE IF (CLASS. EQ. 5. AND. HALO. EQ. 2) THEN HYDL=300 ELSE IF (CLASS. EQ. 5. AND. HALO. EQ. 3) THEN HYDL=900 ELSE IF (CLASS. EQ. 5. AND. HALO. EQ. 4) THEN HYDL=7500 END IF WRITE ( 54, * ) 'SUBSURFACE HYDROLYSIS ( day s /h a If— I ife ) '• HYDL

C QUALITATIVELY ESTIMATE THE BIODEGRADATION POTENTIAL (BIODEO ) OF CHEMICALS C BASED ON THEIR STRUCTURE AND CLASS (QUANTITATIVE METHODS NOT RELIABLE). 80

IF (CLASS. EQ. 1. OR. CLASS. EQ. 3 ) THEN

117

BIODEd= 'T/APTIT -OXIDATION/INHIBITED BY ANAEROBIC SOILS'

118

ELSE IF (CLASS. £0. 2. OR. CLASS. EQ. 4) THEN B I ODEG,* ' MODERATE OXIDATION/INHIBITED BY HIGH CONTAM CONC ELSE IF (CLASS. EQ. 8 ) THEN B IODEG1= 'SLOW OXIDATION IN AEROBIC/ 00 ANAEROBIC SOILS' ELSE IF (CLASS. E0.5) THEN BIODEG= 1 POSSIBLE OXIDATION/INHIBITED BY AEROBIC SOILS' ELSE BIODEG= 1 NO OXIDATION UNDER NORMAL SO IL CONDITIONS END IF WRITE ( 54, *) 'SUBSURFACE BIODEGRADATIONr--- 1 . B IODEG

90

WRITE (54.4) SPACE GO TO 10

C CONTINUE TO PULL DATA FROM FILE UNTIL END IS REACHED - THEN BREAK DO LOOP C AND END THE PROGRAM! ! ! WRITE ( 54, * ) 'END OF DATA FILE ****** CHAO! V 99 STOP END

APPENDIX C Sample computer printout of the 19 input parameters and corresponding 8 hazard indices for two halocarbons. Each of the 75 VOC's in Appendix A was run through the program according to site-specific parameters of the Tucson Airport site described in Chapter I.

119

120

•** TRIBROMOMETHANE (BROMOFORM) 5 0 0 3 0 1 1 0 3033. 000 5.600 2.890 149.300 252.800 0.500 29.000 16.000 1.000 10. 000

OUTPUT DATA: CARCINOGENIC POTENTIAL-DEFINITELY CARCINOGENIC BIOCHEMICAL MECHANISM-FORMATION OF FREE RADICALS AND CARBONYL HALIDES 1.431303 RETARDATION FACTOR FOR DISSOLVED FLOW (dimentionless)21 RETARDATION FACTOR FOR IMMISCIBLE FLOW (dimentionIess)se 2.5115183E+02 SUBSURFACE VOLATILIZATION (mm Hgecubic meter/m(31)mi 1.3616583 SOIL GAS DIFFUSION COEFFICIENT (square cm/hour )se 24.64971 SUBSURFACE HYDROLYSIS (days/balf-1ife)ou 800.0000 SUBSURFACE BIODEGRADATION-POSSIBLE OXIDATION/INHIBITED BY AEROBIC SOILS •** PENTACHLOROETHANE 6 0 5 0 0 1 2 3 480. 000 4.300 1.680 162.000 202.300 0.500 29.000 16.000 1.000 10. 000

OUTPUT DATA: CARCINOGENIC POTENTIAL-DEFINITELY CARCINOGENIC BIOCHEMICAL MECHANISMILFORMATION OF EPDXIDES VIA TRIHALOETHYLENE SPECIES RETARDATION FACTOR FOR DISSOLVED FLOW ( d imen t ion less )= 2.063720 RETARDATION FACTOR FOR IMMISCIBLE FLOW (dimentionless)2 4.3204099E+02 SUBSURFACE VOLATILIZATION (mm Hgecub ic meter /mol )= 5.5327691 SOIL GAS DIFFUSION COEFFICIENT (square cm/hour) om 20.61017 SUBSURFACE HYDROLYSIS (days/ba1f-1ife) NONE SUBSURFACE BIODEGRADATION=NO OXIDATION UNDER NORMAL SOIL CONDITIONS ,

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