EPA/540/2-89/057
October 1989
DETERMINING SOIL RESPONSE ACTION LEVELS BASED ON
POTENTIAL CONTAMINANT MIGRATION TO GROUND
WATER: A COMPENDIUM OF EXAMPLES
United States Environmental Protection Agency
Office of Emergency and Remedial Response
Washington, D.C. 20460
-------
NOTICE
Development of this document was funded by the United States
Environmental Protection Agency under contract No. 68-01-7376
to Booz, Allen & Hamilton inc. It has been reviewed and
approved by the Agency for publication as an EPA document.
The examples provided in this document are exclusively for
reference. They are not designed to support or recommend any
specific approach to determine soil response action levels, nor
are they intended to be relied upon as guidance. The Agency
reserves the right to act at variance with these procedures and
methods at any time.
ii
-------
PREFACE
This document presents case studies illustrating various
methods that have been used at Superfund sites to calculate
soil cleanup levels based on the potential for hazardous
constituents to migrate to and contaminate ground water. In
addition/ several methods for which case studies could not be
identified have been included in a separate section. The
purpose of this document is not to recommend specific methods;
none of the methods or example analyses have been verified over
the long-term. This compendium should be viewed as a resource
which illustrates the importance of assessing the impact of
soil contaminants on ground water and the effects various
parameters have on contaminant migration through the
unsaturated zone. Some of the simpler methods may be used as a
screen during the initial phase of an investigation to
determine the relative importance of this migration pathway.
If it appears that the ground water pathway is significant/ the
descriptions of some of the more complex methods can be used to
identify data needs pertinent to a more accurate assessment of
this pathway.
When selecting or applying a model or methodology for a
particular site/ it is always advisable to obtain advice from
experts in the field during the early stages of the
investigation to ensure that data required by the method will
be collected. Appendix A lists the current technical resources
in the Regions the Ground Water and Engineering Forums
members, and pertinent experts in the EPA laboratories. These
individuals should be consulted during the scoping phase of an
investigation to identify data needs early, and throughout the
investigation as models are applied and evaluated.
ill
-------
-------
TABLE OF CONTENTS
Page
Introduction 1
CASE STUDIES
Fate and Transport Methods
Millcreek, PA (Freundlich) 14
McKin, ME (SOCEM) 21
Geiger/C&M Oil, SC (Summers) 27
Pinette's Salvage Yard, ME (Unnamed) 33
Pristine Inc., OH (Summers) , 39
Chemtronics, NC (SPPPLV) 43
Analytical Methods
Hollingsworth, FL (Leachate Tests) 52
Generic Methods
Woodbury Chemical, CO (Background Levels) .... 56
Distler Farm, KY (Background Levels) 60
Hocomonco Pond, MA (Visible Contamination) ... 62
Pacific Place, B.C. (Remediation Standards) ... 65
METHODS
Fate and Transport Methods
Contaminant Profile 72
AERIS 76
Decision Tree 79
Sewage Sludge Method 84
Generic Methods
Designated Levels (CA) 90
Acceptable Levels (NJ) 95
MED 200 97
Technical Policy (WA) 99
BIBLIOGRAPHY 103
APPENDIX A - Technical Resources 114
APPENDIX B - Glossary of Terms 116
APPENDIX C - Leachate Extraction Tests 122
APPENDIX D - Partition-Coefficients and Water
Solubility Values 128
APPENDIX E - Health-Based Criteria for Ground Water . . 138
APPENDIX F - Natural Migration Reduction Case Study . . 144
v
-------
ACKNOWLEDGEMENTS
This document was developed by EPA's Office of Emergency
and Remedial Response (OERR). Ms. Jennifer Haley of OERR's
Hazardous Site Control Division (HSCD) was the EPA Project
officer/ under the direction of Mr. Bill Hanson, Branch Chief
of Remedial Operations and Guidance Branch. Additional
assistance was provided by:
Melanie Berger
Marlene Berg
Dominic DiGivlio
Seong Hwang
Barnes Johnson
John Matthews
Ossi Meyn
Jon Perry
David Rosenblatt
Jim Ryan
Paul Schumann
Anne Sergeant
Ken Skahn
Joe Slatter
Jeff Starn
Chittibabu Vasudevan
Rick Watman
Ron Wilhelm
Doug Yeskis
Office of Waste Programs Enforcement
Office of Emergency and Remedial Response
Office of Research and Development/Ada
Office of Research and Development
Office of Policy, Planning, and Evaluation
Office of Reserach and Development/Ada
Office of Solid Waste
Office of Solid Waste
U.S. Army/Ft. Detrick
Risk Reduction Engineering Laboratory
Office of Waste Programs Enforcement
Office of Research and Development
Office of Solid Waste
U.S. Army/COE
EPA Region IV
NY/DCE
EPA/Region III
Office of Solid Waste and Emergency
Response
EPA Region V
Booz, Allen & Hamilton assisted OERR in the development of this
document, in partial fulfillment of contract No. 68-01-7376.
The Booz, Allen team included William Hannon, Stephen Zylstra,
and Thomas Haynos.
vi
-------
INTRODUCTION
Purpose
This document presents examples of methods and models used
to establish soil cleanup levels at Superfund sites where
threats to ground water resources exist. It consists of case
studies that illustrate how various methods have been applied
at Superfund sites to derive soil cleanup levels based on the
potential for hazardous constituents to migrate to and
contaminate ground water. In addition, several methods for
which case studies could not be identified are summarized in a
separate section.
The primary purpose of this document is to demonstrate the
importance of assessing the impact of soil contaminants on
ground water and the effect various factors have on the
unsaturated zone. Some of the simpler methods presented here
might be used as a screen during the initial phase of site
characterization to determine the relative importance of this
pathway. If it appears that contaminant migration to ground
water is a significant concern, more complex methods can be
used to determine additional data needed to adeguately assess
this pathway.
Organization of Document
The following sections of the introduction describe the
general process for assessing soil cleanup levels based on the
potential for hazardous constituents to migrate to ground water
and how this analysis fits into the overall remedial
investigation and feasibility study for a site. An overview of
the primary factors affecting pollutant migration in the
subsurface is provided to aid in understanding the reasons
particular parameters are included in the case studies that
comprise Section 2 of this document. A glossary of commonly
used terms in soil and ground water disciplines also is
provided following the introductory pages.
The major portion of this document, Section 2, provides
examples of various methods and models as they were applied.
Individual sites are described with respect to their physical
characteristics and known contaminants. The methods used to
derive soil cleanup levels at these sites are described along
with the site-specific conditions that prompted their use.
Figures 4 and 5 at the beginning of Section 2, summarize the
site-specific data requirements and contaminants of concern for
the sites included to facilitate identification of those sites
with characteristics of interest.
-------
Section 3 discusses additional methods and models for which
case studies could not be identified. Several of these models
were designed as starting points for an investigation rather
than for determining the final soil cleanup levels. Also
documented within the model abstracts, are the original
literature source for reference.
Finally, the appendices of the compendium are designed to
provide the reader with abstracts of some of the available
leachate tests currently being applied; some literature values
and methods to determine partition coefficients and water
solubility values; information concerning health-based criteria
for ground water; and a case study that describes a situation
where natural attenuation of contaminant concentrations
resulted in the achievement of protective soil cleanup levels.
General Principles of Application
As illustrated in Figure 1, the level of soil remediation
required will depend on many site-specific factors, as well as
the hazardous constituents identified and transport processes
involved, and the degree of public exposure at the site.
Therefore, the methods and models used as tools in the analysis
of contaminant migration to ground water will vary from one
site to another depending on the unique site characteristics
and the chemicals involved. In general, the major milestones
in the determination of soil cleanup levels can be depicted as
shown in Figure 2.
Like the EI/FS process as a whole, the method for
determining soil cleanup levels based on potential contaminant
migration to ground water is iterative, with each of several
stages producing an increasingly accurate picture of actual
contaminant migration. Because the data available at different
phases in the RI/FS varies, estimates of soil cleanup levels
may be made using different methods, models, and approaches,
depending on the time at which the analysis occurs. Once
contaminant migration to ground water is determined to be a
pathway of concern at the site, there are three primary methods
for improving the accuracy of projected migration: obtaining
additional data, using more refined data collection techniques,
using more sophisticated models. A combination of these
techniques may be appropriate.
During the scoping phase, limited field data will be
available and an initial estimate of soil cleanup levels might
be made using literature values for model parameters. For
example, literature values of soil/water partition coefficients
might be used in the initial estimate. This estimate could be
refined by analyzing select subsurface samples for organic
carbon content and using this information to calculate the
partition coefficient from literature values of the
octanol/water partition coefficient (generally considered to be
-------
FIGURE 1
Environmental Transfer of Hazardous Constituents
Are Toxics
Present in Soil?
t
Are Toxics 1
LandflDed? I
Ye
i
s
r
No
t
Are Toxics h
Spilled, Leaked or I
Surface Applied? I
t
Is Site 1
Accessible? I
5
5
rts
I
No
1
Does Soil Cover
Prevent Vapor I
Release to Air? I
4
Is Surface
Soil I
Contaminated? I
^
Is Soil . |
Cover i
Eroding? I
|
{
Yes
No
T
I
Is Release to b
Ground Water 1
(Leaching) 1
Possible? 1
_L
Is Release to Soils L
or Surface Water I
(Runoff) I
Possible? 1
4
Is Fugitive Dust ||
Release to
Air Possible? |
_J .,
~~l
Is Volatilization ||
Release to Atr
Possible? I
Yes
i
>
No
Consider Direct
Contact with
Contaminated Soil
I
Does Soil Cover
Prevent Percolation B
of Precipitation? I
^
Yes |
|
i
No
Consider Long- jj
Term Integrity 1
of Son Cover 1
" |-,, ,
^
Does Soil Cover
Prevent Vapor I
Release to Air? I Co
rh j
Yes No No
|
Consider Long- I
Term Integrity i
of Son Cover n
r T ' '
Is Leaching k Is Leakage of k i, volitatoatior
Release to Subsurface! Containerized Uquld 1 RrteSo/S
Soils or Ground Water Waste to Ground B PoSlte?
Possible? Water Possible? | Possbte?
I L
s Surface
Soil I
itaminated?
"I
u
Yes
' r
Is Run
Water, G
or Air (Via
Po
I
Is Soil
Cover
Eroding?
1
No
iff Release h
s, Surface 1
round Water 1]
Volatilization)
sstole?
Yes
No
Yes
No
Yes
No
Yes
No
Go on to Environmental Fate Analysis for Contaminants
Released Via Each Existing or Potential Release Mechanism
-------
FIGURE 2
Process for Determining Soil Cleanup Levels
Determination of
Transport Pathways
(Air, Water, Soil)
Application of
Methods/Models to
Study Transport Rates,
Concentrations
Risk
Assessment
Concentration/Exposure
Levels:
1. Predetermined Levels
2. Percentage of Exposure
from Each Pathway
-------
less affected by site-specific considerations than the
soil/water partition coefficients). The uncertainty in the
estimation might be further reduced by collecting and analyzing
soil cores from the site to calculate actual partition
coefficients or other site-specific characteristics.
The quality of the data itself also will affect the
accuracy of estimates of contaminant migration to ground
water. An iterative process in which data collection
techniques are continually improved should be used during the
remedial investigation to accurately assess the significance of
critical exposure pathways. For example, field analyses and
geophysical techniques may be used in the initial estimate of
contaminant migration with more detailed laboratory analysis of
select samples conducted as the locations and parameters of
concern are identified.
As available data increase, it becomes possible to use
increasingly complex models. A determination of the most
appropriate model should be based on its ability to incorporate
factors of particular concern for the site under investigation,
as well as the resources available to the site manager. There
is always a trade-off between the amount and accuracy of
information provided by the application of sophisticated
models, and the resources available to apply the model (e.g.,
time, expertise, input data, computing facilities).
Once a model has been applied using the initial data, a
sensitivity analysis is performed to determine if reassessment
of the exposure pathway is required. The results of a
sensitivity analysis will help identify any needs for
additional site-specific data. Where possible, actual
monitoring data should be used in combination with calculations
or model projections to show either a lack of contaminant
movement to ground water or to characterize the plume in the
unsaturated or saturated soil zones.
Following remedy implementation, verification sampling is
essential to ensure the accuracy of the predicted
concentrations. Where it is uncertain that levels have been
attained, contingency measures may be warranted. These may
include land use restrictions, site re-evaluation (after some
time period), or a more aggressive "fallback" remedy if actual
contaminant migration is greater than predicted. Some
statistical methods that may be used to verify attainment of
specified cleanup levels have been described in the document
entitled Methods for Evaluating the Attainment of Cleanup
Standards (EPA-230/02/89-042). The Superfund program is
currently evaluating the appropriate use of these statistical
methods at Superfund sites.
-------
More detailed discussions of the overall RI/FS process and
data collection refinement can be found in the Guidance for
Conducting Remedial Investigations and Feasibility Studies
(EPA-540/G-89/004) and the Data Quality Objectives Development
Guidance (OSWER Dir. 9355.0-7A).
Transport Processess Pertinent to Evaluating Migration to
Ground Water
The schematics in Figure 3 indicate the hydrogeochemical
processes affecting pollutants and their associated
environmental transfer media. The fate and transport factors
affecting subsurface contaminant migration processes within
this scheme can be broadly classified as physical, chemical,
and microbial. These processess and the factors affecting
their relative significance at a site are listed in Table 1.
The variety and quantity of such factors make the exposure
route determination more difficult for ground water than for
other exposure pathways. Consequently, arriving at an
acceptable cleanup level based on potential migration to ground
water may warrant a detailed characterization of the site,
needs assessment, and careful selection of analytical tools.
Transport and speciation models rely on the quantification
of relationships between specific parameters and variables to
simulate the effect of natural processes. Therefore, a close
match between the natural processes at the site and those of
the selected model must exist if the modeling exercise is to
provide satisfactory results. For example, a model that does
not consider attenuation of chemicals in the unsaturated zone
would not be appropriate for a site where the depth to ground
water is considerable.
Transport processes strongly depend upon chemical
speciation. The simplest approach to estimating the
concentration of a hazardous constituent is to assume it
behaves conservatively (i.e., does not undergo reaction).
Rigorious models generally include consideration of
transformation, transport, and speciation. In this approach,
the rate constant for first-order attenuation in the
unsaturated zone and the partition coefficient between solid,
liquid, and gas phases must be considered. The inclusion of
degradative processes such as biodegradation and hydrolysis
considerably increases the chemical and environmental data
required to model the fate of a compound, and consequently, the
evaluation of hazard to human health and the environment.
Where such degradative processes are suspected, a more refined
assessment becomes necessary.
-------
FIGURE 3
Media Involved in a Typical Superfund Site
Waste Impoundment
Precipitation
Well
Evapotranspiratlon
Well
Waste Impoundment
(Liquid, Solid or Mixed)
Unsaturated
or
Vadose
Zone
Saturated Zone
PoButfon Plume
-------
TABLE 1
Fate And Transport Processes Affecting Subsurface Migration
Category
Process
Factor Affecting
Process
Physical
Chemical
Microbial
Advection
Dispersion
Flow in fractures
Diffusion
Precipitation
Dissolution
Partitioning
-sorption/desorption
-ion exchange
-volatilization
Equilibrium speciation
-acid/base equilibration
-organic complexation
-inorganic complexation
Abiotic transformation
-hydrolysis
-oxidation/reduction
Oxidation/
reduction and
hydrolysis
Topography
Climate
Precipitation
Soil type
Vegetative cover
Depth to ground water
Soil permeability
Soil void ratio
Soil-moisture
characteristics
Geology
Hydrology
Morphology
Physical/ chemical
properties of
contaminants
Geology
Geology
Contaminants
Microbial environment
8
-------
In summary, the prediction of contaminant transport and
transformation involves the following six steps:
1. Determination of fate-influencing processes (i.e./
transport parameters, partition coefficient)
2. Delineation of environmental compartments
3. Representation of soil/hydrogeologic processes
4. Mathematical representation of speciation processes
(i.e., acid-base, sorption)
5. Mathematical representation of transport and
transformation processess (i.e., precipitation,
dissolution, solubility limits, advection for
dissolved or sorbed phases)
6. Determination of contaminant load and mode of entry
into the environmental media.
Steps 1 through 3 can be formulated during the scoping phase of
a site investigation at which point an initial determination of
the pathways of concern are made. Steps 4 through 6 can be
developed and refined iteratively throughout the RI/FS. Three
levels of refinement in assessing the pollutant may be
considered. These are, in order of increasing complexity:
1. Consider the contaminant as a conservative substance
2. Consider the transport and speciation processes
3. Consider transformation, transport, and speciation
processes.
In conclusion, to accurately predict the fate of
contaminants, the user must have a clear idea of which
processes act on the contaminant, and of those, which are
dominant. Summary exhibits 4 and 5 may be used concurrently as
a quick reference data source to identify sites with specific
hazardous constituents or processes. Exhibit 4 represents a
summary of site-specific data requirements and processes used
to evaluate hazardous constituent migration through the
unsaturated zone at the 11 CERCLA sites documented in this
compendium. Although this table comprehensively summarizes the
requirements and processes used within the case studies, it
should not be viewed as an exhaustive list of parameters
affecting hazardous constituent migration and soil response
action level evaluation and selection. Exhibit 5 compliments
the site-specific data requirements summary by tabulating the
hazardous constituents, identified as contaminants of concern
within the case studies. This tabulation may assist in
-------
reviewing sites with similar constituents to identify the
decision making process used to establish soil response action
levels at these sites.
These exhibits are immediately followed by Section 2,
which presents case studies illustrating various methods that
have been used at Superfund sites to calculate soil cleanup
levels based on potential migration to ground water.
10
-------
FIGURE 4
Site-Specific Data Requirements
and Processes
Mlllcreek, PA
McKI'h, ME
Plnette's Salvage, ME
Pristine^ OH
Chemtronlcs, NC
Hollingsworth, FL
% * / v
Woodbury Chemical, CO
DistlerFarm.KY
Hocomonco, MA
Pacific Place, B.C.
.,
: ^
".
'/ -
: %
;
-<
*
i
.
*
*
: ,
"
-,
: "" %
: ?
%
"
V
'
%
,
: %
.
X
>
;
?
v.\
/
4
, ^
*,*
f
%
%
V
%
s
^
e
.
-------
FIGURES
Contaminants of Concern
to
SITE NAME, STATE II tNORGANICS
EXTRACTABLES
CHOXINS
PESTICIDE/FOB
1 VOLATILE ORGANICS
/
Mlltereefc,PA
McKin.ME "
f "" f^f *"? V ..I
Gelgw/C&MOil.SC
ff f "* vi ** *
Plnette's Salvage, ME
DrlctlnA CIU
rrlSiljiO, On
Chemtronics, NO
Holllngsworth, FL
>' , y f 5 ^ ^f xl
Woodbury Chemical, CO
,. J -":
DIstlerFarm.KY
U*u**«tMnn/w* UA
nocomonco, MA
Pacific Place, B.C.
F
* :
sx
? w
, V
.' :
'
*>*
ff\
'
r°
"
""',
_, |
^:
^;
*:
'
YQ
f
n
»:
v t
5 ^
' .
y*
%
1
*,
1-
*
!^\
^
Y*
|
; -
^
'
^
/*
-, ^
1C'
!^%
^
-V
^
4)
%
^ ^
^
-.
^ >
*i
f f
'*
"4^
"f,$i
,
y*
f
* -, '
' >>
f
*f
r;
*f**
^ ^i
,
«
f*
~*
|J :
1*'* :
^:
5;
'":
It^i
^ :
'
^
fV
5 '
£
"*
%
f<$
%, :
\
*"
| ;
f _,
-
Y*
:
, ^
S :
"
\--
5 :
,
f*
**:
/':
.., :
t
i'f
^ \
yv
%
s"'
$^
*S*
"-
f
'
*" i
s
S
^^
?"*
^
5
r
s
\\
^
^
^.
?f'
₯
^*
H
,
S
1?
{9
t
?s
V»
""^
§%
J^
-
r
g
-N"
^
\
'
Y t
^
*/
s>
»
j,
5^-
V
ATV
5
^ »
S jv
f %*
'J*
' 4
f .
r ^
%
s \^
: % »«
,-
. ^
*"
-r
; * *
5
y
^
/
.^
Y*
/-
% <
%
-
r^T
: ^
,
;
: r
-------
FATE AND TRANSPORT METHODS
13
-------
FREUNDLICH
Site Name; Millcreek, PA
Contaminants; PCBs Copper
PNAs Lead
Phthalates 1,1,1-Trichloroethene
Phenols Vinyl Chloride
Manganese Iron
Depth to Ground Water; Not provided in documentation.
Data Requirements;
- Concentration at receptor well or compliance area
(health-based level or ground water quality goal)
- Lateral plume thickness
- Distance of compliance point from source
- Transverse dispersivity
- Amount of rainfall per year at site
- Total area contaminated with specific contaminant
- Saturated zone thickness
- Ground water velocity
- Lateral source length or lateral extent of source area
- Dry weight concentration of a nonionic organic compound in soil
- Equilibrium pore space aqueous concentration
Methodi Freundlich Equation - This method is designed to
evaluate organic compounds in the unsaturated zone. In the
following case study, it is used in conjunction with the VHS model
to determine estimated dry soil contaminant concentrations which
contribute to elevated ground water contaminant levels (i.e./
above ground water quality goals).
Source: Millcreek, PA, Record of Decision, Appendix B, 1985.
14
-------
FREUNDLICH
Case Study: Millcreek, PA
Waste Description; The site contamination was found in soil,
sediments and ground water. Specific contaminant concentrations
include:
PCBs (31 mg/kg)
PNAs (539 mg/kg)
Phthalates (72 mg/kg)
Volatiles (6 mg/kg)
Copper (20,500 mg/kg)
Lead (2,375 mg/kg)
Phenols (7 mg/kg)
Soil Type; Surficial and near-surface natural deposits consist of
alternating layers of fine sands and silts with occasional clayey
or gravely zones. The thickness of these deposits ranges from 15
feet to 28 feet.
Depth to Ground Water; Ground water at the site occurs both in
water table and semi-confined conditions. The water table extends
into the fill throughout the wet portions of the year. The depth
to ground water varies throughout the site. An average depth was
not provided.
Method Description; The Freundlich method is designed for use
with organic compounds. It is used to determine a dry soil
contaminant concentration which would elevate ground water
contaminant levels above ground water quality goals (e.g., MCLs).
A dry soil contaminant level is calculated for each individual or
group of organic contaminants of concern. At this site, the
Freundlich Equation was used in conjunction with the VHS model
ground water fate and transport equation, which is referred to as
the RAPID assessment model. (Refer to the McKin Case Study for
further information pertaining to the VHS model.) The Freundlich
Equation is:
Qe = (Kd)(Ce)(l/n) (1)
where: Qe = the dry weight concentration of a nonionic
organic compound in soil (mg/kg)
Ce = the equilibrium pore space aqueous
concentration (mg/1)
n = an experimentally derived exponential adjustment
factor to the adsorption isotherm
Kfl = soil:water partition coefficient
In order to use the Freundlich equation, a value for Ce must
be derived. This requires several calculations. The first
calculation involves the VHS model equation or the RAPID
assessment model:
15
-------
FREUNDLICH
erf 2 erf Y (2)
2(At X)172 4(At X)1/2
where: Co = original ground water concentration at the
source area
C = concentration at receptor well or compliance area
Z - saturated zone thickness
X = distance of compliance point from source
Y = width of lateral extent of source
At = transverse dispersivity
erf = error function
By using a health-based level or ground water quality value such as
an MCL for C, the desired concentration in the ground water directly
beneath the contaminant source (Co) that correlates with this value
can be calculated. At this site, the following values were used to
established the PNA cleanup level:
Z = 16 feet
At - 13 feet
C - 0.029 ug/1 (10~6 Unit cancer risk factor direct
ingestion level)
X » 1,000 feet
Y = 2,400 feet
The equation derived a Co value of 0.037 ug/1.
After the original source concentration (Co) is obtained, the
percolation rate through the unsaturated zone is calculated.
Percolation Rate = (percolation)(area) (3)
where: percolation = amount of rainfall per year at site
(in/year)
area = total area of site contaminated with
specific contaminant (ft2)
The values used at the Millcreek site were:
[(11.15 in/year) (1 foot/12 in)] (1,215,000 ft2)
= 1,128,938 ft3/year or 9,743,864 liters/year
The next calculation required to estimate migration is the
lateral ground water flow (LGWF) equation:
LGWF = saturated thickness (ft)
x ground water velocity (ft/year)
x lateral source length (ft) (4)
16
-------
FREUNDLICH
For the Millcreek site the following calculations were
performed:
(16 ft) (60 ft/year) (2,400 ft) = 2,304,000 ftVyear
or 19,885,824 liters/year
The LGWF is then added to the percolation rate to get the total
flow in the saturated zone underlying the contaminated area.
Total Flow = LGWF + Percolation Rate (5)
Total Flow equals:
(9,743,864 + 19,885,824) liters/year = 29,629,688 liters/year
Next, to determine the annual mass of contaminant leaching from
the unsaturated zone (X) the following relationship is used:
= C0 (ug/liter) (6)
Total Flow (liters/year)
To cause a PNA contaminant level of 0.037 ug/1 in the saturated
zone underlying the contaminated area would require the
following:
X = 0.037 ua
29,629,688 liters/year liter
= 1.1 grams
year
The next step in this process is to determine the average
unsaturated pore space aqueous concentration which would cause
the Co in the saturated zone directly below the site to
exceed the calculated value derived earlier. This is estimated
by dividing the annual mass of the contaminant escaping from
the unsaturated zone by the percolation rate.
Co = annual mass (grams/year) (7)
percolation through unsaturated zone
or 1.1 grams/year = 1.13 ug/1
9,743,864 liters/year
Next, Koc and Foc values are determined. Using Koc and
Foc tables, values of 144,561 and 0.018, respectively, were
selected. Using these values in equation (1) and a value of
1.13 ug/1 for the adjustment factor to the adsorption isotherm,
Qe = (Kd)(Ce)(1/n), yielded the following:
17
-------
FREUNDLICH
Qe = (144,561) (0.018) (1.13)
=2.94 mg/kg for a 10~6 risk level
The resultant dry soil concentration is the suggested level of
soil cleanup that would derive a contaminant concentration in
compliance with a ground water quality goal or a health-based
value at a receptor well.
The primary limitations to the Freundlich equation include the
two assumptions that must be made. The model assumes
completely reversible adsorption, which may never be achieved.
It also assumes the rate of adsorption and desorption realize
instantaneous equilibrium. Both of these assumptions are under
debate at this time in the scientific community. Because the
(n) values used to obtain the adjustment factor to the
adsorption isotherm are experimentally derived and can be
different for different ranges of the Freundlich isotherm, they
are difficult to determine. Therefore, they were assumed to be
unity, thus making the isotherm linear. The time investment
required to derive (n) also may be considered a limitation.
Data Requirements/Processes Addressed;
Concentration at receptor well or compliance area
(health-based level or ground water quality goal)
Lateral plume thickness
Distance of compliance point from source
Transverse dispersivity
Amount of rainfall per year at site (in/year)
Total site area contaminated with specific contaminant
(ft2)
Saturated zone thickness (ft)
Ground water velocity (ft/year)
Lateral source length or lateral extent of source area (ft)
Site-Specific Cleanup Goals; The following is a list of the
derived soil cleanup levels for the contaminants found at the
site using the method described above. Also included are the
established acceptable contaminant concentration levels at a
receptor well, as well as the basis for which these levels were
determined. It was assumed that the receptor well location is
onsite in order to ensure cleanup of the entire plume.
18
-------
FREUNDLICH
Soil Cleanup Concentration at Basis for
Compound Criteria (ucr/1) Receptor Well (uo/1) Cleanup Level
PNAs
PCBs
TCE
1,2-DCE
1,1,1-TCA
1,1-DCA
EDC
1,1-DCE
Chloroform
Phthalates
Phenols
2940
116
<10
594
540
760
338,000
9,000
0.0024
0.005
2.8
70.0
22.0
460.0
0.95
0.24
0.19
3.0
300.0
10-6 UCR
background levels
10~6 UCR
HA
HA
AIC
10~6 UCR
10~6 UCR
10~6 UCR
aquatic life RL
taste threshold
HA = Health Advisory, Office of Drinking Water, 1985
UCR = 10~6 unit cancer risk factor
Site-Specific Method Application; In order to establish safe
soil levels to prevent future contamination of ground water,
the following steps were followed:
Determine receptor location - Established by examining
each potential receptor location and the associated
toxicological effects of contaminants. The receptor
pathways were identified as direct, future
down-gradient human ingestion of ground water, chronic
effects on aquatic life in surface water due to
contaminated ground water, and human and wildlife
ingestion of aquatic life in the stream adjacent to the
site.
Determine acceptable contaminant concentrations at
receptor location - Determined by examining the most
current EPA criteria, health advisories, and
appropriate toxicological literature._
Determine source location - Accomplished by examining
soil contamination patterns.
Determine ground water contaminant concentrations at
the source which would bring the contaminant
concentration above acceptable levels at the receptor -
Accomplished by using an appropriate ground water model
called the RAPID assessment model, also known as the
SOCEM I model.
19
-------
FREUNDLICH
Determine soil concentrations which are based on the
ground water contaminant levels at the source that
would result in concentration levels below acceptable
limits at the receptor - Involves establishing an
unsaturated zone contaminant flow model. At this site,
a model for the organics was developed using the
Freundlich equation isotherm, as well as some
additional calculations and measurements such as annual
percolation, area of contamination, ground water flow
velocity, thickness of the saturated zone, and total
organic carbon content of onsite soil. The acceptable
ground water contaminant levels were designed to
protect human health through ingestion of ground water,
through consumption of aquatic life, and to protect
aquatic-life. Levels were established separately in an
additive manner for carcinogens and noncarcinogens.
For carcinogens with a potential for direct human
ingestion, a 10~6 unit cancer risk was deemed
acceptable. Health advisories from the Office of
Drinking Water, September 1985, and MCLs also were used
to establish acceptable contaminant levels. This
methodology was applied to all compounds except PCBs,
which were set at a level based on background PCB
concentrations in the ground water. Health-based
levels were not used because they were below the
background concentrations.
20
-------
SOCEM
Site Name: McKin, ME
Contaminants; Trichloroethylene
Lead
Depth to Ground Water; 35 feet
Data Requirements;
Maximum allowable downgradient concentrations
Saturated zone thickness
Distance from site boundary to receptor
Lateral extent of plume at solid waste boundary
- Transverse dispersivity
Concentration of contaminants in soil
- Concentration of contaminants in ground water directly below
the source
- Soil:water partition coefficient
Method; SOCEM - This method is a version of the Vertical and
Horizontal Spread (VHS) model equation which includes the use of
site-specific data. Unlike the RCRA delisting procedure, SOCEM
also incorporates a method for determining a soil cleanup level
that corresponds to the maximum allowable contaminant level in
ground water at some downgradient receptor.
Source; Ct^M Hill; Soil Contaminant Evaluation Methodology
(SOCEM). In Guidance on Remedial Actions for Contaminated Soils
at CERCLA Sites (Draft); and "Groundwater," May-June edition, 1985,
21
-------
SOCEM
Case_Sti3fly: McKin, ME ..
Waste Description; Removal operations have occurred at the site,
including removal of pumpable liquid wastes from above ground
tanks and drums/ and disposal of all onsite barrels/ containers,
above ground tanks and drums. The remaining contamination
problems are onsite surface and subsurface soil contamination and
offsite ground water contamination. Soil contamination is located
in several "hot spots" and contain primarily volatile organics and
some metals. Trichloroethylene was found in concentrations up to
1,500 ppm. The depth of contamination was found at 6 feet or less
in some locations and to at least 12 feet in other areas.
Additionally/ 16 buried drums were found onsite.
Soil^Type; The site area is located on a relatively permeable
glacial outwash plain comprised of stratified sand, gravel, and
boulders overlying heavily weathered granitic bedrock.
Depth to Ground Water: The top of the ground water table is
estimated to be at an average depth of 35 feet.
Method Description; SOCEM incorporates the ground water fate and
transport equation from the Vertical and Horizontal Spread (VHS)
model. The model was used as part of the RCRA hazardous waste
evaluation procedure to determine if contaminant concentrations in
leachate from a hazardous waste landfill warrant classifying it as
a hazardous substance. Values for factors used in the VHS
equation, when applied as a delisting model were estimated, taken
from scientific literature, or assumed to be a specific value for
every site. For instance, the value for the distance from the
waste boundary to the receptor location was designated as 500
feet. SOCEM is a version of the VHS model equation which includes
the use of site-specific data. Unlike the RCRA delisting
procedure, SOCEM also incorporates a method for determining a soil
cleanup level that corresponds to the maximum allowable
contaminant level in ground water (e.g., water quality criteria)
at some downgradient receptor.
To use SOCEM, the first step is to calculate the allowable
concentration in the ground water directly below the contaminated
source. Given the maximum allowable concentration, the initial
source concentration can be calculated by the VHS equation
(described in the Millcreek Case Study).
22
-------
SOCEM
After deriving the initial source concentration (Co) by using
the VHS equation/ the next step is to convert this maximum
allowable ground water contaminant concentration to an allowable
soil contaminant concentration. This is done by using a partition
coefficient (K^) defined by the following, where Co = Cwater:
Kd = CSQJI (ug/g) (1)
cwater (ug/ml)
(Several other methods to determine K^ values are described in
Appendix D.) Finally/ the required soil cleanup concentration
level can be determined by multiplying the allowable concentration
in the ground water directly below the site by the partition
coefficient:
Csoil = (Cwater) x (Kd) <2)
Data Requirements/Processes Addressed;
Maximum allowable downgradient concentration
Saturated zone thickness
Distance from site boundary to receptor
Lateral extent of the plume at the solid waste boundary
Transverse dispersivity
Concentration of contaminants in soil
Concentration of contaminants in ground water directly below
the site
Soil:water partition coefficient
Effective porosity
Hydraulic conductivity
Hydraulic gradient
Longitudinal dispersivity
Downgradient plume concentration
Ground water velocity
23
-------
SOCEM
Site-Specific Cleanup Goals: Using trichloroethylene (TCE) as an
indicator chemical, the SOCEM model was used to predict a soil
cleanup level of 0.1 ppm. This level was selected to prevent
downgradient ground water contamination from exceeding the water
quality criteria level of 28 ppb for TCE.
Site-Specific Method Application: Several analytical solution
models were considered at the McKin site to estimate the
contaminant concentrations in ground water at the contaminant
source and at the location of the nearest potential receptor. TCE
was chosen as the indicator compound at the site. This selection
was based on the onsite concentration of TCE, its frequency of
occurrence, its physical and biological characteristics (i.e.,
solubility, Koc/ and biodegradation susceptibility), and its
observed concentration relative to the USEPA Preliminary
Protective Concentration Limits (PPCL). These are guideline
levels that should not be exceeded and are based on long-term, low
levels of exposure through ingestion of potable water (Salee,
1984).
The SOCEM model was chosen as the most appropriate to be applied
because it predicted an onsite ground water TCE concentration (117
ppm) similar to an actual onsite measured value from an onsite
monitoring well (130 ppm). (Refer to Exhibit 1 for a list of the
parameters used in deriving the predicted concentration.)
Additional support is given to this predicted concentration
because the value of 117 ppm is approximately one-tenth of the
maximum solubility of TCE in water, which is 1,100 ppm. In
Transport of Organic Contaminants in Groundwater by MacKay et al.,
the author states that organic compounds are rarely found in
ground water at concentrations approaching their solubility
limits. The observed concentrations are usually found to be a
factor of 10 lower than their solubility limits.
The results from this predictive stage indicate that SOCEM is an
acceptable model for application at the McKin site. The next step
in the process is to estimate the ground water contaminant
concentration at the source that results in a downgradient ground
water contaminant concentration that would not exceed the water
quality criteria level of 28 ppb for TCE. Using the SOCEM model
and the site-specific parameters including a downgradient distance
of 200 feet (the distance to the site boundary), a ground water
TCE concentration of 0.096 ppm at the contaminant source was
predicted.
With these data, the contaminated soil cleanup level that
corresponds to the allowable concentration in the ground water
beneath the source can be estimated. Applying the partition
coefficient value, equation (2) Csoii = (Cwater)(Kd) described
in the SOCEM model, a soil with a five percent organic matter
content yields a soil TCE concentration of 0.1 ppm.
24
-------
SOCEM
Exhibit 1
MCKIN PARAMETERS
Input Parameter
Value
Qo = Contaminant Flow Rate
B = Saturated Thickness
ne = Effective Porosity
K = Hydraulic Conductivity
i = Hydraulic Gradient between
the site and well B-l
V = Ground Water Velocity = Ki
ne
I = Longitudinal Dispersivity
t = Transverse Dispersivity
C = Downgradient Plume
Concentration at well B-l
X = Distance from the site to
Well B-l
125 aal = 16.7
yr yr
15 ft
0.25
7xlO-4 cm = 724.3 f_t
sec yr
250'-224' = 0.0325
800'
(723.4UO.0325) = 94.0 ft
0.25 yr
= 0.26 ft
day
10m (32.8 ft)
1m (03.3 ft)
28 ppb (16 ppm - predictive
test)
200 ft (800 ft - predictive
test)
25
-------
SOCEM
Specifically:
0.09 na x 1.1 ml = 0.11 ug or 0.11 ppm
ml g g
Therefore/ the model predicts that a site boundary TCE
concentration of 96 ppb can be reached by achieving a TCE soil
cleanup level of 0.1 ppm.
26
-------
SUMMERS
Site Name; Geiger/CSM Oil, SC
Contaminants; PCB-Aroclor 1254
Toluene
Trichloroethylene
Lead
Mercury
Chromium
Depth to Ground Water: 2 feet
Data Requirements:
Volumetric flow rate of infiltration (soil pore water) into
aquifer (ft3/day)
- Darcy velocity in aquifer
- Ground water seepage velocity
- Void fractions (ground water volume/volume of solid)
- Horizontal area of contamination
Volumetric flow rate of ground water (ft^/day)
Thickness of aquifer
Background contaminant concentration in aquifer (ug/1)
- Contaminant concentration in the infiltration (ug/1)
Method: Summers Model - This model assumes that a percentage of
rainfall at the site will infiltrate and desorb contaminants from
the soil based on equilibrium soil:water partitioning. Using
ground water modeling/ the soil cleanup level is calculated from
the original soil concentration, the concentration of the
infiltrating water, and an equilibrium coefficient.
Source; Summers, K.S., Gherini and C. Chen, Tetra Tech Inc.,
Methodology to Evaluate the Potential for Groundwater
Contamination from Geothermal Fluid Release. EPA-600/7-80-117,
1980, as modified by EPA Region IV.
27
-------
SUMMERS
Case Studv: Geiger/C&M Oil, SC
Waste Description; Contaminants of concern found in the
surface soil consist of the following:
Organics Metals
PCBs-Aroclor 1254 (4,000 ppb) Lead (740 ppm)
TCE (230 ppm) Mercury (1.3 ppm)
Toluene (460 ppb) Chromium (1,100 ppm)
The depth of soil contamination is estimated to be five feet in
the oil-stained area and one foot in other areas of the site.
Soil Type; Soils at the site are predominately sandy
throughout their profile, but contain silt and interspersed mud
lenses.
Depth to Ground Water; The average ground water lies at a
depth of two feet below the surface. Depth to the water
surface varies seasonably, reaching a minimum of one foot below
the ground surface. The uppermost aquifer at the site is a
surficial, unconfined aquifier, approximately 40-50 feet thick,
composed of silty, fine to medium sand with mud lenses.
Method Description; The Summers model was developed to
estimate the point at which contaminant concentrations in the
soil will produce ground water contaminant concentrations above
acceptable levels. The resultant soil concentrations can then
be used as guidelines in estimating boundaries or extent of
soil contamination and specifying soil cleanup goals for
remediation.
The model assumes that a percentage of rainfall at the site
will infiltrate the surface and desorb contaminants from the
soil based on equilibrium soil:water partitioning. It is
further assumed that this contaminated infiltration will mix
completely with the ground water below the site, resulting in
an equilibrium ground water concentration with all contaminants
in the final mixture from the infiltration.
This model begins by estimating the concentration of the
contaminant infiltration that would result in ground water
concentrations at or below target levels. For this model the
mixing rate of infiltration and ground water is estimated. The
mixing of uncontaminated ground water with contaminated
infiltration and the resultant concentrations in ground water
can be calculated using the following equation:
28
-------
SUMMERS
(QpCp) (QACA)
Cgw - - 1_1 - (1)
QP + QA
where:
Cgw = contaminant concentration in the ground water (ug/1)
Qp - VDz»Ap
= volumetric flow rate of infiltration (soil pore
water) into the aquifer (ftVday)
VDZ = Vs»e
= Darcy velocity in the downward direction
Vs = ground water seepage velocity
e = void fraction = ground water volume/volume of solid
Ap = horizontal area of pond or spill
Cp = concentrations of pollutant in the infiltration at
the unsaturated-saturated zone interface
QA = VDhw
= volumetric flow rate of ground water (ft-Vday)
VD = Darcy velocity in aquifer
h = thickness of aquifer
w = surface pond for spill width perpendicular to flow
direction in aquifer
CA = initial or background concentration of pollutant in
aquifer.
The maximum allowable contaminant concentration in the
infiltration (leachate) that would not result in a ground water
concentration exceeding a water quality goal, such as an MCL/
can be determined by using this water quality goal for Cgw in
the previous equation and solving for the infiltration
contaminant concentration:
cgw(Qp +
Cp = _ _ _ _ (2)
Qt
29
-------
SUMMERS
Once the maximum allowable contaminant concentration in the
leachate has been determined, the contaminant concentration in
the soil can be calculated. This is the soil cleanup level
which needs to be attained in order to be protective of the
ground water and can be derived from the following soil:water
partitioning equation:
Cs = (Kd)(Cp) (3)
where:
Cs s soil concentration (ug/kg)
Cp = concentrations in the infiltration (ug/1)
» an equilibrium partition coefficient (ml/g).
The use of Kg is based on the assumption that equilibrium
conditions are maintained between the distribution of pollutant
in solution and on the solid phase. Because equilibrium is
more closely approached in slow moving soil pore water and
ground water than in rapidly flowing surface water systems/ it
is feasible to apply K^ to soil pore water and ground water
systems. Several methods to determine K^ values are
described in Appendix D.
Data Requirements;
. Volumetric flow rate of infiltration (soil pore water)
into the aquifer (ft3/day)
Darcy velocity in aquifer
. Ground water seepage velocity
, Void fraction (ground water volume/volume of solid)
. Horizontal area of pond or spill
. Volumetric flow rate of ground water (ft^/day)
Thickness of aquifer
Initial or background concentration of pollutant in aquifer
Concentration of contaminants in the infiltration (ug/1)
30
-------
SUMMERS
Site-Specific Cleanup goals; Using the calculations as
described below, these preliminary soil cleanup goals were
established:
Benzo( a) anthracene (0.140 mg/kg)
Benzo(b and/or K)f luoranthene (0.170 mg/kg)
PCB-Aroclor 1254 (1.050 mg/kg)
Chromium (3.7 mg/kg)
f
Lead (166.5 mg/kg)
1,1-Dichloroethane (0.00278 ug/kg) .
Site-Specific Method Application; The Summers model, described
earlier, was used at this site to determine the soil
contaminant concentration level that would prohibit . future
leachate from exceeding target ground water concentrations.
Using the following relationship, the target ground water
cleanup concentrations and the mixing rate were used to back
calculate contaminant concentrations in the leachate. This
model is a derivation of the original equation (Summers, et al;
1980):
Qp + Qgw
where: Cqw = contaminant concentration in ground water
Qp = volumetric flow rate of infiltration (soil
pore water) into ground water (ft^/day)
Qqw = volumetric flow rate of ground water
(ftVday)
Cp = contaminant concentrations in the infiltration.
For this application, the volumetric flow rate of infiltration
(Qp) is measured as the total rainfall from the site minus
the potential evapotranspiration. The contaminant
concentrations in the ground water are then related back to
soil concentrations using the soil:water equilibrium
relationship as discussed in the model description.
The partition coefficient (K^) that was used in the model at
this site was derived from the following equation:
^d ~ (KOC) (Foc)
where: Koc = organic carbon partition coefficient
Foc = fraction of organic carbon in the soil.
31
-------
SUMMERS
No measurements were taken at the site/ therefore the fraction
of organic carbon in the soil was assumed to be 0.5 percent
(typical for sandy soils).
These calculations yield soil cleanup levels which may prevent
ground water from exceeding established protective criteria.
32
-------
UNNAMED
Site Name: Pinette's Salvage Yard, ME
Contaminants: PCB - Aroclor-1260
1/4-Dichlorobenzene
1,2,4-Trichlorobenzene
Chlorobenzene
Benzene
Chloromethane
Depth to Ground Water; Ranged from 0-6 feet
Data Requirements;
Volumetric flow rate of recharge flowing downward through a
unit area (ft3/day)
Volumetric flow rate of ground water in saturated zone in
water column through unit width (ft3/day)
Concentration of contaminant in ground water recharge
Hydraulic conductivity (ft/day)
Hydraulic gradient (ft/ft)
Concentration of contaminant adsorbed to the soil in the
unsaturated zone (ug/kg)
Concentration of contaminant in ground water in saturated
zone (ug/1)
Total organic carbon concentration (mg/mg)
Method; Unnamed - This method is a variation of the Summers
Model. A separate critical soil concentration or soil cleanup
level is derived for both saturated and unsaturated soils
designed to prevent ground water from exceeding regulatory or
health-based levels. These cleanup values are calculated based
on ground water contamination, equilibrium partitioning and
dilution.
Source; Pinette's Salvage Yard Feasibility Study, Appendix B,
(Draft), 1989.
33
-------
UNNAMED
Case Studv: Pinette's Salvage Yard, ME
Waste Description; The contamination at the site was found in
ground water and soils. The contaminants of concern and their
maximum concentrations were as follows:
PCB-Aroclor-1260 (92 ppb)
1,4-Dichlorobenzene (5.1 ppm)
1,2,4-Trichlorobenzene (510 ppm)
Chlorobenzene (260 ppb)
Benzene (18 ppb)
Chloromethane (58 ppb)
Soil Type; There are four distinct soil units at the Pinette
site: surficial soils (alluvium), a clay/silt confining unit, a
sequence of glacial till/glacial outwash, and a bedrock unit.
Depth to Ground Water; Portions of the site consist of wetlands
or "ground water breakout" areas. Two distinct aquifers under the
site are separated by an intervening clay layer found 2 to 6 feet
below the ground surface extending to depths of 12 to 16 feet.
The clay unit acts as a aquitard in the shallow allivial aquifer,
resulting in a saturated thickness ranging from 2 to 3 feet.
Method Description: This Unnamed method developed soil cleanup
criteria using established ground water regulatory and
health-based levels coupled with an equilibrium partitioning
approach.
Soil cleanup levels are calculated for saturated and unsaturated
soils assuming equilibrium between dissolved and adsorbed phases
for each contaminant using the following relationship:
Ssat = (KaXCsat)
-------
UNNAMED
Next/ the desired contaminant concentration for ground water is
determined using established health-based criteria (i.e., MCLs/
cancer risk values) . The cleanup criteria may now be calculated
using equation (1) .
Subsequent calculations to derive unsaturated soil cleanup
criteria include the assumption that dissolved contamination in
the ground water recharge reaches equilibrium with the absorbed
phase on unsaturated soils, and that such recharge is fully
diluted into the entire water column upon reaching the water
table. Thus, cleanup criteria for unsaturated soils are
established using equation (1) and a dilution equation for
calculating (Csat) the contaminant concentration in the ground
water in the saturated zone.
Csat = (4)
combined with equation (3) yields the following relationship.
This equation is used to calculate the cleanup criteria for soils
in the unsaturated zone.
sunsat = /e (5)
where: Sunsat = concentration of contaminant adsorbed
to the soil in the unsaturated zone
(ug/kg)
and the ground water volumetric flow rate through the
saturated zone (Q) is estimated from Darcy's Law:
Q = (K)(i)(A) (6)
where: K = hydraulic conductivity (ft/day)
i = hydraulic gradient (ft/ft)
A = area of flow (unit width x saturated thickness of
aquifer) (ft2)
35
-------
UNNAMED
Data Requirements/Processes Addressed;
Concentration of contaminant adsorbed to the soil in the
saturated zone (ug/kg)
Concentration of contaminant in ground water in saturated zone
(ug/1)
Total organic carbon concentration in soil (mg/mg)
. Octanol-water partition coefficient
. Concentration of contaminant in ground water recharge
. Volumetric flow rate of recharge flowing downward through unit
area (ft3/day)
. Volumetric flow rate of ground water in the saturated zone
throughout the water column (ft3/day)
Site-Specific Cleanup Goals; Using the calculations described
below and the values listed in Exhibit 2, the following soil
cleanup goals were established:
Saturated Unsaturated
Soils Soils
PCB-Aroclor-1260 (8,700 ug/kg) (5,394,000 ug/kg)
1,4-Dichlorobenzene (42 ug/kg) (26,000 ug/kg)
1,2,4-Trichlorobenzene (7,800 ug/kg) (4,836,000 ug/kg)
Chlorobenzene (20 ug/kg) (12,000 ug/kg)
Benzene (0.42 ug/kg) (260 ug/kg)
Chloromethane (0.05 ug/kg) (30 ug/kg)
Site-Specific Method Application; At Pinette's Salvage Yard Site
the Foc was estimated to be 0.1 percent. For Aroclor-1260,
KQW is given in Walton (1984) as 1.38 x 107. Using equation
(2), the distribution coefficient (K(j) was estimated as follows;
Kd = (0.63)(0.001)(1.38 x 107)
= 8.69 x 103
The ground water cleanup criteria (Contract Laboratory Required
Quantitation Limits) used for Aroclor-1260 was 1.0 ug/1. Using
equation (1) the corresponding soil cleanup criteria in the
saturated zone was determined:
ssat = (8.69 x 103)(1.0)
= 8,700 ug/kg
36
-------
Exhibit 2
SOIL CLEANUP CRITERIA FOR PINETTE'S SALVAGE YARD
CO
-J
Compound
Ground Water
Cleanup
Criteria Source
(ug/1)
Octanol-Water
Partition(Kow)
Coefficient
Distribution
Coefficient(Kd)
(ml/g)
Unsaturated Conditions!
Aroclor-1260
1,4-Dichlorobenzene
1,2,4-Trichlorobenzene
Chlorobenzene
Benzene
Chloromethane
Critical Soil
Concentrat ion(s)
(ug/kg)
Saturated Conditions;
Aroclor-1260
1, 4-Dichlorobenzene
1,2, 4-Trichlorobenzene
Chlorobenzene
Benzene
Chloromethane
1
27
680
47
5
10
CRQL
MEG
Risk-Based
Hazard Index
MEG
MEG
CRQL
1.38 x 107
2.45 x 103
1.82 x 104
6.92 x 102
1.35 x 102
8.13 x 102
8.69 x 103
1.54 x 10°
1.15 x 101
4.36 x 10-1
8.50 x 10~2
5.72 x 10~3
8,700
42
7,800
20
0.42
0.05
5,394,000
26,000
4,836,000
12,000
260
30
1. Ground water cleanup criteria derived from health-based criteria, Maine Maximum Exposure Guidelines
(MEGs) and Contract Laboratory Program Contract Required Quantitation Limits (CRQLs).
2. Octanol-water partition coefficients (Kow) are based on Walton, 1984.
3. The distribution coefficient (K,j) is a function of the octanol-water partition coefficient, and the
soil total organic carbon concentration (Foc) as follows: K
-------
UNNAMED
The soil cleanup criteria in the unsaturated zone were calculated
using equation (5). In order to use equation (5)/ however, a
value for (Q), the volumetric flow rate through the saturated
zone/ must be calculated using equation (6).
Q = (45 ft/day)(0.025)(2.5 ft2)
= 2.25 ftVday
Assuming an annual recharge rate of 20 in/year and a unit area of
1 ft2/ a value for the volumetric flow rate of recharge flowing
downward through a unit area (e) was estimated as 4.6 x 10~3
ft3/day. Referring back to equation (5) (e + Q)/e is equal to
620. Therefore/ the critical unsaturated soil concentrations will
be 620 times the critical saturated soil concentrations for any
individual contaminant. For Aroclor-1260, this value was
calculated as follows:
Ssat = (8/700 ug/kg)(620)
= 5,394/000 ug/kg.
38
-------
SUMMERS
Site Name: Pristine Inc., OH
Contaminants; Aldrin Dieldrin
Benzene PAHs
Chloroform 2,3,7,8-TCDD
DDT Tetrachloroethene
1,1-Dichloroethene Trichloroethane
1,2-Dichloroethene
Depth to Ground Water; Ranges from 0-46 feet
Data Requirements;
Volumetric flow rate of infiltration (soil pore water) into
aquifer
- Darcy velocity in aquifer
Ground water seepage velocity
- Void fraction (ground water volume/volume of solid)
- Horizontal area of contamination
- Volumetric flow rate of ground water (ft^/day)
- Thickness of aquifer
Background contaminant concentration in aquifer (ug/1)
Contaminant concentrations in the infiltration (ug/1)
Method; Summers Model - Refer to Geiger Case Study for full
description.
Source; Summers/ K.S., Gherini and C. Chen, Tetra Tech, Inc.,
Methodology to Evaluate the Potential for Groundwater
Contamination from Geothermal Fluid Release. EPA-600/7-80-117,
1980, as modified by EPA Region IV.
39
-------
SUMMERS
Case Study: Pristine Inc., OH
Waste Description: As part of the Public Health Evaluation,
11 compounds were identified as "chemicals of concern" based on
frequency, concentration and potential threat. These compounds
were:
Aldrin 1,2-Dichloroethene
Benzene Dieldrin
Chloroform PAHs
DDT 2,3,7,8-TCDD (dioxin)
1,1-Dichloroethene Trichloroethane
Tetrachloroethene
Soils are contaminated to a depth of approximately 14 feet.
Soil Type; The site geology consists of five distinct soil
units: fill, upper lake sediment, glacial till, lower lake
sediment, and lower outwash. The outwash and other glacially
derived sediments are about 180 feet thick underlain by 2 aquifers.
Depth to Ground Water; The top of the upper aquifer lies
within the upper lake sediments, which is estimated to be
approximately 0-46 feet. The precise depth of the ground
water table was not specified in the Record of Decision (ROD).
Because there are wetlands adjacent to the site, however, the
water table is expected to be near the surface.
Method Description; (Summers Model - See Geiger Case Study for
full description)
Data Requirements/Processes Addressed;
Volumetric flow rate of infiltration (soil pore water)
into the aquifer (ft3/day)
Darcy velocity in aquifer
Ground water seepage velocity
Void fraction (ground water volume/volume of solid)
. Horizontal area of pond or spill
Volumetric flow rate of ground water (ft3/day)
Thickness of aquifer
Surface pond for spill width perpendicular to flow direction in
aquifer
. Initial or background concentration of pollutant in aquifer
. Concentration of contaminants in the infiltration (ug/1)
40
-------
SUMMERS
Site-Specific Cleanup Goals; Using the Summers calculations
described in Geiger Case Study/ the following cleanup criteria
were derived:
Benzene (116 mg/kg)
1/2-Dichlorobenzene (19 mg/kg)
Trichlorobenzene (175 mg/kg)
Site-Specific Method Application; The preliminary performance
goals for soil were designed to prevent cancer risks from
exceeding 10~6 as a result of exposure to the chemicals of
concern. After calculating soil cleanup levels based on dermal
exposure and ingestion of soil, the "Summers" model was used to
verify that soil cleanup concentration levels/ based on the
above exposure pathways, were also protective of ground water.
Of the 11 contaminants of concern identified at the site, model
calculations indicated that the concentrations of 3 of the
contaminants would exceed MCLs.
The mixing of ground water/ infiltrating water and the
resultant contaminant concentrations in ground water were
related as follows:
c - (QpMCp) ,,v
<~gw - S- ₯. (1)
Qp + Qgw
where: Cgw = contaminant concentration in the ground water
(ug/1)
Qp = volumetric flow rate of infiltration (soil
pore water) into the ground water (ft^/day)
Cp = contaminant concentration in the infiltration
Qgw = volumetric flow rate of ground water
(ft3/day)
The volumetric flow rate of infiltration (Qp) was derived
based on the total rainfall from the site, 10 inches, and
attributed 15 percent to ground water recharge, or approximately
6 in/year.
This quantity is assumed to have fallen over the entire site on
120,000 square feet corresponding to a Qp value of 164 ft3/day.
The volumetric flow rate of ground water (Qgw) is estimated as the
average linear ground water velocity times the area of the aquifer
perpendicular to the ground water flow across the contaminated area
of the site or 8/900 ft3/day.
41
-------
SUMMERS
This value was derived using the following equation:
Qgw = (k)(i)(l)(d) (2)
where: k = hydraulic conductivity (139 ft/day)
i = hydraulic gradient (0.00245 ft/ft)
1 = length of the site perpendicular to flow (600 ft)
d = depth of aquifer or mixing zone (43.4 ft)
The hydraulic conductivity was based on regional pumping
tests. The depth of the mixing zone was taken to be one-third
the depth that the area municipal wells were screened.
The concentration in the infiltrating ground water (Cp) was
predicted using the following relationship:
Cs = (Kd)(Cp) (3)
where: Cs = measured soil concentration (ug/kg)
Kfl = soil:water equilibrium partition coefficient
(liter/kg)
Cp = concentration in infiltration (ug/liter)
In this case/ the partition coefficient (K(j) was derived by
multiplying the organic carbon water partition coefficient
(Koc) by the fraction of organic carbon (Foc) as follows:
Kd = (4)
The fraction of organic carbon was assumed to be 0.5 percent
based on descriptions of soil found onsite.
A back calculation was subsequently performed to determine the
appropriate soil performance level required to prevent the
ground water contaminant levels from exceeding MCLs. These
levels were selected as the target cleanup level for the
contaminants.
42
-------
SPPPLV
Site Name: Chemtronics, NC
Contaminants:
Toluene
Lead
RDX
Benzophenone
Chromium
TNT
Picric acid
2-Chlorobenzolmalonitrile
Depth to Ground Water;
Data Requirements;
Ranges from 0-40 feet
Measured concentrations of contaminants in soil and other
media of critical pathways
Acceptable daily intakes for each contaminant
- Distance from site receptor
- Rate of offsite migration
- Rate of contaminant degradation
Method; SPPPLV - This method was developed by the U.S. Army.
It requires the identification and measurement of pollutants
present/ pathways of exposure, and the determination or estimation
of an acceptable daily dose of each contaminant to a receptor.
Source; U.S. Army, "Single Pathway Preliminary Pollutant Limit
Values and Preliminary Pollutant Limit Values (SPPPLV and PPLV),"
In Inventory of Cleanup Criteria and Methods to Select Criteria.
(Unpublished Report), G.M. Richardson, Environment Canada, 1987.
43
-------
SPPPLV
Case Study: Chemtronics, NC
Waste Description; Every environmental medium was found to be
contaminated at this site, including ground water/ surface
water, sediments, air and soil. The indicator compounds
selected at the site included nine volatile organic compounds,
three explosive compounds, three chemical warfare agents and
two metals. The concentrations of contaminants found varied
with each area. Some of the higher levels founds in the soil
were :
Toluene (21,000 mg/kg) Lead (35 mg/kg)
RDX (290 mg/kg) Chromium (97 mg/kg)
TNT (280 mg/kg) Picric acid (22 mg/kg)
2-Ch'lorobenzalmalonitrile Benzophenone (9.3 mg/kg)
(CS) (3,100 mg/kg)
Soil Type; The soil types were not provided in the Record of
Decision (ROD) .
Depth to Ground Water; Ground water recharge in the onsite
area is derived primarily from local precipitation. Generally,
the depth of the water table depends on the topography and rock
weathering at the site. The ground water table varies from the
ground surface in the valleys (streams) to more than 40 feet
below the ground surface in sharply rising slopes. The ground
water underlying the site has been classified as lib, using
USEPA Ground-Water Protection Guidelines.
Method Description; The method applied at Chemtronics is a
mathematical model developed by the U.S. Army to determine
site-specific cleanup- levels. It requires the identification
and measurement of pollutants present, pathways of exposure,
and the determination or estimation of an acceptable daily dose
of each contaminant to a receptor.
Single pathway preliminary pollutant limit values (SPPPLV) for
all pathways and contaminants are calculated from measured
levels of contaminants at a particular site. The acceptable
daily intake for each contaminant, as well as site-specific
factors such as distance to receptor, rate of offsite
migration, and rates of dilution and degradation are used in
the model. Assuming that contaminants are in equilibrium along
all exposure pathways from source to receptor, partition
coefficients can be used to determine levels of contaminants in
different media along the exposure pathways. Critical pathways
are selected for each contaminant, and a preliminary pollutant
limit value (PPLV) is then derived for each medium by
normalization of the SPPPLV using the following equation;
n
PPLV = (I _ 1 _ )-!
1 ( SPPPLV) i
44
-------
SPPPLV
In order to establish PPLVs the best available toxicological
information is used to estimate an acceptable daily dose
for human exposure to each compound (Exhibit 3). A PPLV is
derived from consideration of the D^- along with the probable
exposure level.
The soil contaminant concentration is related to the ground
water concentration through the following relationships:
where: Cs = acceptable contaminant concentration in soil
Cw = acceptable contaminant concentration in water
Ksw = partition coefficient (soil/water)
From the estimated Dj-/ an estimated ground water limit value
is expressed as:
Ground Water PPLV = Dt x body weight (2)
daily water intake
The PPLV for ground water, which has been calculated using an
acceptable daily intake, can then be used to derive an
appropriate site-specific soil cleanup level.
This model is applicable to all sites, receptors and
contaminants, and can be applied to multimedia and multi-
contaminant exposures. /
Data Requirements;
Measured concentrations of contaminants in soil and other
media of critical pathways
Acceptable daily intake for each contaminant
Various site-specific parameters, including distance from
site to receptor, rate of off site migration, and rates of
dilution and degradation of contaminants.
Site-Specific Cleanup Goals; The PPLVs established for
explosives and chemical agents at the site were determined for
both soil and drinking water based on predicted exposure
pathways. The contaminant levels determined to be safe to
human health according to the PPLV method were as follows:
TNT (305 mg/kg) RDX (95 mg/kg)
Picric acid (38,000 mg/kg) 3-Quinuclidinol (25.7 mg/kg)
CS (43.4 mg/kg) Benzophenone (15 mg/kg)
45
-------
SPPPLV
Exhibit 3
ACCEPTABLE EXPOSURE LEVELS
Information sources from which to derive values of acceptable
daily doses (D^) of toxic pollutants for humans (order of
priority)
Input Information
Calculation
Required
Reference
Existing Standards
Acceptable daily intake
(ADI)
Maximum concentration
level (MCL) in drinking
water
Threshold limit value
(TLV) for occupational
exposures
FDA guidelines for
concentrations in
foods
None
Adjust for water
consumption level
Use factors for
breathing rate,
exposure time,
safety factor of 10~2
Use factors for
consumptions of
particular foods
Experimental Results
in Laboratory Animal Studies
Lifetime no-effect
level (NELL)
Ninety-day no-effect
level (NEL90)
Acute toxicity
Use safety factor of
10~2
Use safety factor of
10~3
Use safety factor of
1.155 x 10~5
WHO (1962)
EPA (1975)
ACGIH (1980),
Cleland, et
al, (1987)
FDA
Vettorazzi
(1976)
Vettorazzi
(1976)
Rosenblatt
(1982)
46
-------
SPPPLV
Site-Specific Method Application: The presence of residual
contamination from the three chemical agents and three
explosives onsite presented a special problem with respect to
establishing target cleanup levels. Since these chemicals lack
or have minimal data concerning health standards or
toxicological information/ the preliminary pollutant limit
value method was selected to develop acceptable response action
levels. The application of the PPLV method was modified at the
Chemtronics site. At this site the acceptable soil
concentrations and acceptable water concentrations were
determined separately and not related by the Ksw.
The PPLVs for 3-Quinuclidinol, as one of the target compounds/
were calculated by first establishing a D^ level. Using the
LDso value of 179 mg/kg (Exhibit 4), and a safety factor of
1.5 x 10~6 according to the Layton method (Layton et al.,
1987), a Dt of 2.7 x 10~4 mg/kg/day was derived. Using
this Dfc value in equation (2) a PPLV for ground water is
calculated as follows:
Ground Water PPLV = pt x body weight
daily water intake
= 2.7 x 10-4ma/ka/dav x 70 kg
2 liters
= 0.009 mg/1
For soil/ two exposure pathways/ ingestion and absorption, were
considered. The action level for soil concentrations that
provide reasonable protection for soil ingestion by a 15 kg
child is then calculated by:
Soil ingestion (SPPPLV) = Dt x body weight
amount of soil ingested
= 2.7 x 10-4mg/kg/dav x 15 kg
0.0001 kg soil
= 40.5 mg/kg
The specific pathway preliminary pollutant limit value for skin
absorption is based on a 10kg child absorbing only 38.6 x
10~6 kg of soil in a day. This is calculated as follows:
Skin Absorption (SPPPLV) for soil = Dt x child weight
kg soil/day
= 70 mg/kg
47
-------
SPPPLV
Exhibit 4
PARAMETER VALUES FOR CHRONIC HUMAN EXPOSURE
USED AT CHEMTRONICS
Parameters
Adult body weight
Adult water intake
Adult breathing rate
Adult dust inhalation
(rural)
Child body weight
(1 to 6 yrs)
Soil from which
contaminants would be
removed through skin
absorption by child
Soil ingestion by 15 kg
child
De minimis risk for small
populations (less than 10
million)
Temperature
Value
70 kg
2 I/day
18.5 m3/24 hr
0.06 mg/m3/day
15 kg
0.0386 g/day
0.1 g/day
10-4
25°C
48
-------
SPPPLV
The PPLV for soil when considering ingestion and skin absorption
is then calculated by:
Soil PPLV = 1
40.5 70
25.7 mg/kg
49
-------
-------
ANALYTICAL METHODS
51
-------
LEACHATE
Site Name: Hollingsworth, FL
Contaminants; Copper
Nickel
Lead
Depth to Ground Water; At or near surface.
Pa£a_JBe qu i r emen t s;
- Advisory levels of contaminants (e.g., PPCLs)
Method; Exposure Assessment Using Leachate Tests - This
methodology employs leachate extraction tests on contaminated
soils and applies them to existing health advisory levels.
Source; Contaminated Soils Workgroup Preliminary Findings and
Recommendations, (Draft), Exposure Assessment Using Leachate
Tests Methodology.
52
-------
LEACHATE
Case Study; Hollingsworth, FL
Waste Description; The onsite soil contained contaminants
including copper (21.7 ppm)/ nickel (0.3 ppm), and lead
(0.2 ppm).
Soil Type: The first 60 to 70 feet of soils are primarily
composed of fine to medium grained sands. This zone is
underlain by a transition zone of cemented shell and sandstone/
and finally by limestone, which forms the major water
transporting zone of the aquifer.
Depth to Ground Water; The Biscayne Aquifer/ a highly
permeable, wedge-shaped, unconfined shallow aquifer/ underlies
the site and is the primary source of drinking water for 3
million residents. The top of the aquifer is near the natural
ground surface in the area of the site.
Method Description; The methodology employed at this site
applied various leachate extraction tests to contaminated soils
to determine estimated contaminant concentration levels in
leachate. Acceptable leachate levels were related to site
conditions and advisory levels (e.g., primary pollutant
concentration levels, or PPCLs). Extraction procedures used
include the EP Toxicity Test for substances with drinking water
standards, as well as the Toxicity Characteristic Leaching
Procedure (TCLP). All leachate tests were used in conjunction
with a modified version of Trescott and Laren's (USGS) Finite
Difference three-dimensional ground water fate and transport
model in order to determine the "reasonable worst case"
protection levels in soil.
The advantage in using this methodology is its ability to
relate concentration and mobility of the hazardous substance to
site-specific conditions. For additional information on the
use of leachate tests for determining soil cleanup levels and a
description of several of the tests available, refer to
Appendix C.
Data Requirements; The only information required to apply this
method is the advisory levels of contaminants/ such as PPCLs/
and leachate analysis of soil samples from representative
locations at the site.
Site-Specific Cleanup Goals; The cleanup goals for soil were
established based on drinking water standards. The contaminant
concentration in the leachate from the soils were not to exceed
a level 10 times the appropriate State water quality criteria.
Hence, the cleanup criteria were as follows: copper (10 ppm),
nickel (1.0 ppm), lead (0.5 ppm), and total VOCs (1.0 ppm).
53
-------
LEACHATE
Site-Specific Method Application; The attainment of cleanup
goals at this site for metal-contaminated soil were determined
based on the concentration of the metals in the soil leachate
(as determined by an EP Toxicity test). The cleanup goals for
soil were set at the level at which the leachate from these
soils did not exceed 10 times the appropriate State water
quality criteria/ following negotiations between EPA and the
FDER. A factor of 10 has been designated by Region 4 as a
conservative baseline in estimating the level of the dilution
of leachate as it reaches the ground water. The soil then was
excavated to these cleanup goals using the results obtained
from the EP Toxicity test to indicate when the selected cleanup
levels had been achieved.
54
-------
GENERIC METHODS
55
-------
BACKGROUND
Site Name; Woodbury Chemical, CO
Contaminants: Alpha-BAC
Iron
Manganese
Acetone
Ground Water Depth: 20 to 27 feet
Data Requirements:
- Background levels of contaminants in on- or offsite soils
Method: Background Levels - This method requires that a
background soil contaminant concentration be established for
use as a guide in determining soil cleanup levels.
Source: Contaminated Soils Workgroup/ Preliminary Findings and
Recommendations/ (Draft), Background Levels Methodology.
56
-------
BACKGROUND
Case Study; Woodbury Chemical, CO
Waste Description; An estimate of 5/470 cubic yards of onsite
soil and sediments/ as well as offsite sediments are
contaminated with three general types of contaminants including
pesticides, metals and other organic compounds. The high
concentrations are found in "hot spots" where rubble had been
deposited. Pesticide-contaminated soils were found at varying
depths at the site/ indicating that some downward migration has
occurred/ but they do not appear to have dissolved into ground
water in large amounts. The pesticide concentrations across
the site ranged from below detection limit to 151/515 ppm for
alpha-BHC. Iron and manganese were found at concentrations as
high as 32/600 ppm and 1,200 ppm respectively, and acetone was
detected at 15 ppm.
Soil Type; Bedrock lies at a depth of about 30 feet below
alluvial deposits.
Depth to Ground Water; The ground water hydrology of the area
is characterized by unconfined aquifer conditions in the
alluvium and semi-confined aquifer conditions in the underlying
bedrock. The water table is located 20 to 27 feet below the
ground surface.
Method Description; The use of the background contamination
method requires that a background contaminant concentration
level at the site or offsite must be established as the target
cleanup level for onsite soils. This ensures the site will be
cleaned up to the level prevailing in the area.
The primary advantage to using this methodology is protection
of public health and the environment by returning contaminant
levels to the original background level. In addition, once the
background level is established, attainment of this cleanup
level can be determined through total contaminant concentration
analysis of the soil. These analytical results can be obtained
relatively quickly and with less effort compared to using a
model or other methodology.
Data Requirements; Background levels of contaminants in on- or
offsite soils.
Site-Specific Cleanup Goals; Due to the carcinogenic
properties of aldrin and dieldrin, a risk-specific dose cleanup
level of 1.0 ppm and 0.5 ppm/ respectively/ was set for these
pesticides. The limit value selected for the remaining
pesticides is that total soil concentration not exceed 3.0 ppm,
as determined using background concentrations and the
methodology detailed in the following section.
57
-------
BACKGROUND
Site-Specific Method Application; The following criteria were
used to determine the appropriate residual pesticide
concentrations or proposed pollutant limit value (PPLV) that
should be set for cleanup of this site:
"Typical" pesticide residual soil concentrations in
urban areas
Comparison to RCRA standards
Potential cancer risk.
The contaminant pesticides at the site are the types that were
available for use in the urban environment from the 1960s to
the mid-1970s for pest control. Therefore, typical pesticide
residual soil concentrations were calculated based on summary
data for the period 1969-1976 from the National Soils
Monitoring Program. Urban soils data for the concentrations of
chlordane, heptachlor, heptachlorepoxide, dieldrin, endrin,
toxaphene, and total DDT from five cities were selected to
represent a western or Great Plains urban environment. A value
of 3.0 ppm total pesticides was selected as a appropriate
cleanup level because, based on the data received, it is an
approximate average urban total pesticide soils concentration.
In order to ensure that the 3.0 ppm cleanup value was a
legitimate and acceptable value, it was first compared to the
established RCRA concentration of 0.005 mg/1 for toxaphene in
ground water directly outside of a site boundary (40 CFR
264.94(a)(1)). The 3.0 ppm value was determined, using a
volumetric calculation method to represent 5.0 kg of total
pesticide remaining on the 2.2-acre site. The potential
delivery of pesticides to the alluvial aquifer (at a depth of
20 feet) was calculated based on the following:
Relative concentrations of pesticides in the soil -
toxaphene found to comprise approximately 90 percent
of the total pesticides, chlordane approximately 3
percent, and all others 1 percent or less.
Solubility of pesticides - values taken from published
data and selected and used to represent the most
realistic conditions.
Pesticides half-lives - values from current literature
obtained for the half-life for each pesticide. Values
integrated with the calculated travel time to estimate
degradation.
Recharge to site - consisted of a water balance
equation that considered net precipitation and
permeability of the soil. Modified Darcian equations
used to estimate recharge.
58
-------
BACKGROUND
Dilution by the alluvial aquifer - considered in the
delivery calculations and included permeability,
transmissivity and storativity calculations.
Empirically-derived adsorption equations were then used to
calculate concentrations in the alluvial aquifer at the site
boundary, based on an urban background soil concentration of
3.0 ppm. The derived water concentration was 0.000035 mg/1,
which is greater than two orders of magnitude less than the
RCRA concentration limits, so the cleanup level of 3.0 ppm was
considered to be protective.
59
-------
BACKGROUND
Site Name; Distler Farm, KY.
Contaminants; Arsenic
Bis(2-ethylhexyl) phthalate
Chromium
Di-n-butyl phthalate
Lead
Isophorone
Benzene
Toluene
Trichloroethylene
Tetrachloroethylene
Naphthalene
Depth to Ground Water; 5 to 10 feet
paLtSLJRequirements;
- Background levels of contaminants in on- and offsite soil.
jMethod; Background Levels - This method requires the
determination of background soil contaminant concentration to
be used as a baseline for the establishment of soil cleanup
levels.
gource; Contaminated Soils, Workgroup, Preliminary Findings
and Recommendations, (Draft), Background Levels Methodology.
60
-------
BACKGROUND
Case Study; Distler Farm, KY
Waste Description; Contaminants of concern found in soil
samples within the area of contamination include arsenic/
chromium, lead, benzene, toluene, trichloroethylene,
tetrachloroethyelene, naphthalene, bis(2-ethylhexyl) phthalate,
di-n-butyl phthalate, and isophorone. Test data indicated that
the contaminants have been released, distributed, or have
migrated to soil depths ranging from six inches to four feet.
Soil Type; The upper soil layers are primarily clayey and
silty in nature and range from 5 to 20 feet. The average depth
is approximately 15 feet.
Depth to Ground Water; The onsite water table fluctuates due
to seasonal flooding, the average depth to ground water is
approximately 5-10 feet.
Method Description; This method requires that an average
background contaminant level in offsite soils be determined in
order to establish the target cleanup level for onsite soils.
This method ensures that the site will be cleaned up to the
same level as the prevailing levels in the surrounding area.
Once the background level is established, attainment of this
cleanup level can be determined through laboratory analysis of
the soil. These analytical results can be obtained relatively
quickly and with less effort in contrast to modeling techniques.
Data Requirements; Background concentrations of contaminants
of concern in uncontaminated or offsite soils.
Site-Specific Cleanup Goals; With the exception of arsenic,
which was detected at background levels of 20 ppm in area
soils, soil background levels for contaminants of concern were
equal to the method detection limits (2.5 to 100 ppm). These
contaminants were not detected in uncontaminated soils in the
area.
Site-Specific Method Application; All contaminated soils were
to be excavated to background levels and disposed of in an
offsite permitted hazardous waste landfill. For estimating
purposes, the depth of excavation that would be required to
reach background level was assumed to be 11 feet. During
excavation, periodic sampling was performed to ensure that when
"background" levels were obtained, excavation efforts were
stopped.
61
-------
VISIBLE CONTAMINATION
Site Name; Hocomonco Pond, MA
Contaminants: Benzo(a)pyrene Dibenzofuran
Naphthalene Pyrene
Phenanthrene Flourene
Anthracene Arsenic
2-Methyl naphthalene Chromium
Flouranthene Lead
Benzo(a)anthracene
Chrysene
Depth to Ground Water; Not provided in documentation.
Data Requirements:
- Visible identification of and distinction between
contaminated and noncontaminanted soils
MeJAod: Visible Contamination - The soils are removed to a
depth at which they are no longer visibly contaminated.
Source; Contaminated Soils Workgroup/ Preliminary Findings and
Recommendations, (Draft), Background Levels Methodology.
62
-------
VISIBLE CONTAMINATION
Case Study: Hocomonco Pond, MA
Waste Description; Site contaminants were found in the air,
ground water, surface water, sediments, and soil. Specific
soil samples taken from the Kettle Pond area and several other
isolated areas contained the following contaminants:
Benzo(a)pyrene (ND - 11 ppm)
Naphthalene (0.007 - 0.141 ppm)
Phenanthrene (0.002 - 0.129 ppm)
Anthracene (0.003 - 0.050 ppm)
2-Methyl naphthalene (0.007 - 0.012 ppm)
Fluoranthene (0.006 - 0.483 ppm)
Benzo(a)anthracene (0.004 - 0.097 ppm)
Chrysene (0.001 - 1.0 ppm)
Dibenzofuran (ND - 0.017 ppm)
Pyrene (ND - 0.287 ppm)
Fluorene (ND - 0.207 ppm)
Arsenic (1-21 ppm)
Chromium (2-52 ppm)
Lead (1-21 ppm).
The depth of soil contamination in the Kettle Pond area extends
from the surface to a depth of 26 feet (maximum depth sampled
and analyzed).
Soil Type; The typical stratigraphic sequence of surficial
deposits from base to top of the site consists of 0-4 feet of
dense lodgement, till under 0-100 feet of delta forset beds,
followed by 0-30 feet of delta topset beds.
Depth to Ground Water: The site was divided into four primary
areas. The depth to ground water varied throughout these
areas. It was determined, however, that the excavation of
soils was necessary at only two of the areas, Kettle Pond and
Hocomonco Pond. The depth to ground water was not provided
specifically for either of these areas.
Method Description; The method used at this site targets
visibly contaminated soils for cleanup. Soils are removed to a
depth at which they are no longer visibly contaminated. This
methodology assumes that soils that are not visibly
contaminated will not significantly contaminate ground water or
present a threat through dermal contact. It may be
appropriate, if data indicate, that contaminants have not
migrated beyond the layer where visible contamination exists.
Data Requirements; Visible identification of and distinction
between contaminated and noncontaminated soils.
63
-------
VISIBLE CONTAMINATION
Site-Specific Cleanup Goals: The primary limits of soil
excavation for this site have been chosen based on visual
contamination criteria.
Site-Specific Method Application; The remedial action
recommended for the Kettle Pond area consisted of excavation of
contaminated soil with disposal in an ohsite RCRA landfill.
The extent of soil excavation (i.e., the target cleanup level)
was based primarily on visible contamination criteria but
included post-excavation boring and monitoring well sampling to
ensure all highly contaminated soils were removed. The
sampling and analyses was used to identify an area where the
visible contamination ceased and a sharp decrease in
concentrations occurred. This depth was targeted as the actual
depth of excavation. Subsequent ground water monitoring was
planned to ensure that contaminated soils were excavated to the
depth necessary to mitigate potential ground water
contamination. The range of visible contamination observed in
the Kettle Pond area was 11 to 17 feet; however, the extent of
excavation beyond visible contamination and highly contaminated
soils/ based on a marked reduction in contaminant
concentration, was expected to be approximately 2 to 3 feet
beyond this in order to be protective.
64
-------
REMEDIATION STANDARDS
Site Name; Pacific Place, British Columbia, Canada
Contaminants: Exhibit 5 provides a detailed list.
Depth to Ground Water; Not provided in documentation.
Data Requirements;
- Types and levels of contaminants found onsite
The intended land use for the site after remediation
efforts are completed
Method; Investigation and Remediation Standards - This
methodology uses established criteria and projected future land
uses of a site to establish soil cleanup criteria.
Source; British Columbia Standards for Managing Contamination
at the Pacific Place Site, Ministry of Environment, Waste
Management Program, Victoria B.C., April 5, 1989.
65
-------
REMEDIATION STANDARDS
Exhibit 5
INVESTIGATION AND REMEDIATION STANDARDS
FOR PACIFIC PLACE
HEAVY METALS
Arsenic
Barium
Cadmium
Chromium
Cobalt
Copper
Lead
Mercury
Molybdenum
Nickel
Selenium
Silver
Tin
Zinc
Soil (mg/kg) or (ppm) of dry matter
A B C
5
200
1.0
20
15
30
50
0.1
4
20
2
2
5
30
500
5
250
50
100
500
2
10
100
3
20
50
50
2000
20
800
300
500
1000
10
40
500
10
40
3000
80
OTHER INORGANICS
Bromide (free)
Cyanide (free)
Cyanide (total)
Fluoride (free)
Sulfur (total)
20
1
5
200
500
MONOCYCLIC AROMATIC HYDROCARBONS (MAHs)
Benzene 0.1
Ethylbenzene 0.1
Toluene 0.1
Chlorobenzene 0.1
1,2-Dichlorobenzene 0.1
1,3-Dichlorobenzene 0.1
1,4-Dichlorobenzene 0.1
Xylene 0.1
Styrene 0.1
PHENOLIC COMPOUNDS
Nonchlorinated phenols 0.1
Chlorophenols (each) 0.1
Chlorophenols (total) 0.1
0.5
5
3
1
1
1
1
5
5
1
0.5
1.0
500
50
10
50
400
1000
300
100
500
2000
2000
5
50
30
10
10
10
10
50
50
10
5
10
1500
66
-------
REMEDIATION STANDARDS
Exhibit 5
(Continued)
Soil (mg/kg) or (ppm) of dry matter
A B C
POLYCYCLIC AROMATIC HYDROCARBONS (PAHs)
Benzo(a)anthracene 0.1
1,2-Benzanthracene 0.1
Dibenzo(a,h)anthracene 0.1
Chrysene 0.1
3-Methylchloanthrene 0.1
Benzo(b)fluoranthene 0.1
Benzo(i)fluoranthene 0.1
Benzo(k)fluoranthene 0.1
Benzo(g,h,i)perylene 0.1
Benzo(c)phenanthrene 0.1
Pyrene 0.1
Benzo(a)pyrene 0.1
Dibenzo(a,h)pyrene 0.1
Dibenzo(a,i)pyrene 0.1
Dibenzo(a,l)pyrene 0.1
Indeno(l,2,3-cd)pyrene 0.1
Acenaphthene 0.1
Acenaphtylene 0.1
Fluoranthene 0.1
Fluorene 0.1
Naphthalene 0.1
Phenanthrene 0.1
PAHs(total) 1
CHLORINATED HYDROCARBONS
Aliphatic (total) 0.3
Chlorobenzene (total) 0.1
Hexachlorobenzene 0.1
.Polychlorinated biphenyls 0.1
PESTICIDES
Pesticides (total) 0.1
GROSS PARAMETERS
Mineral oil and grease 100
Light aliphatic 100
hydrocarbons
1
1
1
1
1
1
1
1
1
1
1
10
1
1
1
1
1
1
1
1
1
1
20
7
4
2
5
1000
150
10
10
10
10
10
10
10
10
10
10
10
100
10
10
10
10
10
10
10
10
10
10
200
70
20
10
50
20
5000
800
67
-------
REMEDIATION STANDARDS
Case Study: Pacific Place, British Columbia, Canada
Waste Description; The contaminant classes to be addressed at
this site include heavy metals, pesticides/ PCBs, and petroleum
based products. See Exhibit 5 for specific contaminants.
Soil Type; Not provided in documentation.
Depth to Ground Water; Not provided.
Method Description; The Ministry of Environment has
established specific criteria for soil and ground water
remediatiion based on criteria from various Canadian
environmental agencies such as the Canadian Council of Resource
and Environmental Ministers, the Province of Quebec, the
Ontario Ministry of the Environment, regulatory guidelines such
as Canadian drinking water quality guidelines, and pollution
control objectives. The Ministry of Environment has
established specific criteria for soil and ground water
remediation.
As seen in Exhibit 5, three soil levels, A, B and C, are used
as investigation and remediation standards for establishing
soil cleanup levels. Investigation standards are contaminant
concentrations, which when exceeded require detailed
investigation to oversee the extent of contamination and nature
of the hazard. Remediation standards are contaminant
concentrations which when exceeded require action to reduce
exposure to potential receptors. The levels are described
below.
Level A: This level represents approximate achievable
analytical detection limits for organic compounds in
soil, and natural background levels of metals and
inorganics. For soils with constituents at or less
than this level, the soils are considered
uncontaminated. For residential land use, level A is
the investigation standard.
For soil containing contaminants at concentrations
greater than level A, but less than level B, the soil
is considered slightly contaminated, but remediation
is not required.
Level B: This level is an intermediate value, approximately 5
to 10 times above level A. For residential and
recreational land use this level is the remediation
standard, while for exclusive commercial or industrial
land use it is the investigation standard.
68
-------
REMEDIATION STANDARDS
For soil contaminants with concentrations exceeding
level B, but less than level C, the soil is considered
contaminated, and requires remediation to levels less
than level B, if the land is used for residential or
recreational purposes. Remediation will not be
required if the land is used exclusively for
commerical or industrial activities.
Level C: At this level/ contamination of soil is significant.
For exclusive commerical or industrial land use, level
C is the remediation standard. For soils containing
contaminants exceeding this level, all uses of the
land will be restricted pending the application of
appropriate remedial measures, which will redtice
contaminant concentrations to levels less than level C.
Data Requirements/Processes Addresses:
The type and levels of contaminants
The intended land use of the site after remediation.
Site-Specific Cleanup Goals; The specific cleanup levels for
this site have not been established, however, the investigation
and remediation standards will be used to define these levels
once remediation efforts begin (Exhibit 5).
Site-Specific Method Application: At the Pacific Place site, a
thorough investigation of the types and concentrations of
contaminants of the site has been completed. The investigation
also revealed that the property is intended for mixed
residential, commerical, park, and recreational use.
69
-------
-------
FATE AND TRANSPORT METHODS
71
-------
Contaminant Profile Model (ContPro)
Source; Williams/ J.R., T.E. Short, C.L. Eddington and C.G.
Enfield, "Contaminant Transport and Fate in
Unsaturated Porous Media in the Presence of Both
Mobile and Immobile Organic Material," Draft Report,
U.S. EPA, Robert S. Kerr Environmental Research
Laboratory, Ada, OK, 1988.
Data Requirements/Processes Addressed:
- Initial total concentration of contaminant in system on a
mass basis of total sample. Input as depth and
concentration.
- Volume fraction of immobile organic phase on a volume basis
of total sample. Input as depth and volumetric fraction.
- Initial concentration of mobile organic phase on a mass
basis of total sample. Input as depth and concentration.
- Solidrwater partition coefficient
- Immobile organic:water partition coefficient
- Mobile, immiscible organic:water partition coefficient
- Vapor:water partition coefficient (dimensionless Henry's
Law coefficient)
- Volume fraction of the immobile organic phase (m^/m3)
on a volume basis of the total sample
- Initial concentration (kg/kg) of the mobile organic phase
on a mass basis of the total sample
- Density (kg/m3) of the solid phase, water phase, immobile
organic phase, mobile organic phase and vapor phase
- Total pore fraction, or porosity, of the system (m3/m3)
- Half-life (days) for the contaminant in the solid phase,
immobile organic phase, mobile organic phase and vapor phase
- Recharge rate at which water is being supplied to the
ground water system
- Diffusion coefficient (m2/day) for the contaminant in the
water phase, mobile phase and vapor phase
- Saturated hydraulic conductivity (m/day)
- Clapp-Hornberger constant for the soil being used.
72
-------
Model Description;
This model was developed as a tool for estimating the transport
and fate of chemicals from sites where initial concentrations
of contaminants are known as a function of depth. One of the
objectives of the model is to provide an estimation of the
amount of contamination that will leave the unsaturated zone
and enter the ground water. This is accomplished through the
calculation of the amount leached. The following description
provides a brief overview of the main components of this model.
Transport of contaminants through the following five phases is
considered: water, stationary inorganic/ immobile organic,
mobile organic, and vapor. The mobile organic phase has become
a concern because recent research has shown that the
partitioning of chemicals between dissolved organic carbon and
water may be of considerable importance. In certain disposal
situations, the mobile organic phase, in addition to the water
phase, flows through the soil, thereby enhancing the mobility
of potentially hazardous chemicals, particularly hydrophobic
chemicals which are adsorbed to the mobile organic phase. The
total concentration of contaminants is composed, of
contributions from all five phases. The following equation
describes this relationship:
CT = (1-n) PsCs +
©aPaca + mPmcm + nvPvcv
where: Op = initial total concentration of the
contaminants in the sample (kg/kg)
n = total pore fraction, or porosity, of the
system (m3/m3)
C = concentrations of the contaminant
(kg/kg) in the solid(s), water(a),
immobile organic(i), mobile organic(m),
and gaseous (v) phases
p = densities of the solid(s), water(a),
immobile organic(i), mobile organic(m),
and gaseous (v) phases in (kg/m3)
$ - volume fraction of the immobile (i) and
mobile (m) organic phases in the total
sample (m3/m3)
0a = volume fraction of the water phase in
the total sample
n = total pore fraction, or porosity of the
system (m3/m3) .
Independent relationships (R) must be obtained between each of
the phases and the total concentrations, thus allowing
independent calculation of the concentration of each
contaminant in each phase. This can be done by defining five
new terms such that:
73
-------
CT RgCg - RiCi - RaCa
Assuming linear partitioning and local equilibrium, the R terms
can be defined in terms of partition coefficients. Another
assumption is that the interface between each of the phases is
water and the other phases do not contact each other. Thus,
contaminant transfer from one phase to another must include
transfer through the water phase. The partition coefficients
can be defined as follows:
Cg - KsCa Cm -
GI - KiCa Cv =
where:
Ks = solidzwater partition coefficient
KI » immobile organicrwater partition coefficient
Km = mobile, immiscible organicrwater partition
coefficient
Kv » vapor :water partition coefficient.
Several methods for determining partition coefficient values
are described in Appendix D.
Now the equation can be rewritten in terms of the partition
coefficients and the respective phase concentrations. For
example, the total soil concentration and the R terms can be
expressed as follows:
= Cs [(l-n)ps + (<|>iPiKi + 0pa
i'mPmKm
Rs = (l-n)ps
.
nvPvKv)/Ks
These equations are formulated for each phase within the source
document .
Output Parameters of the Model;
Cst concentration (kg/kg) of contaminant in the solid phase
of the system.
Ca: concentration (kg/kg) of contaminant in the water phase
of the system.
Cj.: concentration (kg/kg) of contaminant in the immobile
organic phase of the system.
Cm: concentration (kg/kg) of contaminant in the mobile
organic phase of the system.
74
-------
Gv: concentration (kg/kg) of contaminant in the vapor phase
of the system.
Volatilization losses from the surfade of the system.
Total contaminant leached from the soil profile.
Limitations;
The following factors are not addressed:
Recharge rates
Hydraulic conductivity - water content relationships
Depth to ground water
Spacial and temporal variability of the above parameters.
Case Studies;
Mississippi Wood Treatment/ MS.
75
-------
Title; Aid for Evaluating the Redevelopment of Industrial
Sites (AERIS) model.
Source; Bulman/ T.L./ K.R. Hosier/ B. Ibbotson, D. Hockley,
and M.J. Riddle/ "Aid for Evaluating the Redevelopment
of Industrial Sites (AERIS) Model," In Development of
a Model to Set Cleanup Criteria for Contaminated Soil
at Decommissioned Industrial Sites, Environment
Canada, Senes Consultants Ltd. and Moneco Consultants
Ltd./ Canada/ 1988.
Data Requirements/Processes Addressed;
- Physical and chemical characteristics of contaminants
- Type(s) of receptor(s) (child or adult)
- Proposed land use
Site-specific environmental data, including soil
characteristics
- Nontoxic threshold levels for contaminants.
76
-------
Model Description:
This model/ currently under development, links exposure
assessment (multimedia pathways models) with toxicity
assessment as part of an overall risk evaluation procedure.
Information about the site being studied/ the environmental
behavior of a contaminant in site soil and future site use are
used in model calculations. The model is enhanced by
incorporating information for various Canadian environments/
organic and inorganic substances/ and algorithms for detailed
estimation of transport in the soil system. These include the
RITZ and VIP models, currently being developed by the U.S.
Environmental Protection Agency. An "expert system" shell is
being employed to facilitate the transfer of information
between the model user/ the model data base and computational
procedures. A flow diagram of AERIS model functions is
illustrated in Figure 1.
Input screens allow the user to enter site-specific data or to
rely on default values which are provided from an internal data
base. Input questions relate to the chemical of concern
(physical and chemical characteristics), the type of receptor
to be studied (adult or child), the proposed land use
(residential/ agricultural/ commercial or recreational) and
characteristics of the site environment and soil. The user
also can input nontoxic threshold levels, such as levels
predetermined by regulation (i.e./ guidelines for drinking
water).
The AERIS program calculates the concentrations of a pollutant
in soil, water, air and plants and the resulting exposure to a
human receptor according to the selected land use. Algorithms
which evaluate environmental pathways include chemical
properties of the pollutant, as well as differential flux
equations for mass transfer and flow through porous media. A
field study at a petroleum refinery in Nanticoke/ Ontario/
owned by Texaco Canada, Inc. is being conducted to evaluate
model algorithms which could be used as components of the
overall AERIS model to improve environmental pathways
analysis. The RITZ model currently is being assessed. This
model predicts the proportions of a contaminant which will be
degraded, volatilized and leached in soil, based on soil and
waste characteristics, kinetic parameters of degradation, and
volatilization and phase partitioning.
The exposure assessment includes ingestion of dirt and dust/
ingestion of produce and field crops, ingestion of drinking
water, and inhalation of vapors and particulate matter.
Default values are provided for assumptions relating to the
ingestion or inhalation of the pollutant for each receptor
77
-------
under various land use scenarios including active and passive
behavior, indoors and outdoors, and in winter and summer
months. These values can be changed by the user, if desired,
to create a site-specific scenario. Risk assessment is
performed by calculation of exposures of the receptor and
comparison to nontoxic threshold levels. If exposure estimates
are greater than nontoxic threshold levels, the estimate of
initial soil concentration is reduced and the transport and
fate pathways analysis procedure is repeated. The procedure is
terminated when concentrations in soil have been identified
which could be allowed at the site without exceeding the
acceptable exposure levels.
Output for the AERIS model includes a comparison of soil,
water, air and plant concentrations with nontoxic threshold
levels and predetermined regulatory levels. A comparison of
soil concentration with resulting pollutant exposure to a human
receptor and the proportion that each exposure pathway
contributes to the overall exposure is also provided.
Limitations:
The following factors are not addressed:
- Water movement
- Partitioning between soil, waste water and waste oil
- Diffusion in air and water phases.
Case Studies;
development.
None available model is still under
r
INPUT
SITE CHARACTERISTICS
PROPERTIES OF
POLLUTANT
LAND
USE/RECEPTOR
ACCEPTABLE
EXPOSURE
FIELD EVALUATION
for example - RITZ
TRANSPORT
PATHWAYS
- Concentration In Soil,
Water, Air, Plants
OUTPUT
SOIL CRITERIA
Soil Concentration vs.
Exposure
Soil Concentration vs.
Predetermined Levels
Proportion of Each
Exposure Route
FIGURE 1.
Flow Diagram of a Method for Selecting Clean-Up Criteria AERIS Model
78
-------
Title; Decision Tree Process
Source; California Department of Health Services - Toxic
Substance Control Division, Site Mitigation Decision
Tree Manual/ 1986.
Data Requirements/Processes Addressed;
- Initial chemical concentration of infiltration water in the
unsaturated zone (mg/1)
Initial chemical concentration in soil in the unsaturated
zone (mg/kg)
Partition coefficient (mg/1)/(mg/kg)
- Mass of soil per unit volume of soil (kg)
Fraction of immobile water (pore water)
Flow rate in horizontal direction from the unsaturated zone
d3/t)
- Flow rate in vertical direction from the unsaturated zone
U3/t)
- Initial chemical concentration in water in the saturated
zone (mg/1)
- Chemical concentration entering vertically from the
unsaturated zone (mg/kg)
- Mean monthly precipitation or rainfall (ft/yr)
- Mean monthly runoff (1)
- Actual evapotranspiration (1)
Cross-sectional area of aquifer within cell (ft2)
Hydraulic conductivity of aquifer (cm/sec)
Hydraulic gradient in the aquifer (ft/ft)
,Retardation Factor derived from partition coefficient
79
-------
Model Description;
This methodology evaluates the movement of chemicals through
the unsaturated zone/ and is used to estimate the
concentrations of organic chemicals in the saturated zone as
water infiltrates through an unsaturated soil column. The
concentration in the ground water depends on the residual
concentration in the soil prior to infiltration.
When estimating potential contaminant concentrations in ground
water/ advective transport resulting from infiltrating ground
water and attenuation must be considered. The Decision Tree
Process incorporates a retardation factor based on the carbon
and clay content in soils. It is assumed that the unsaturated
zone usually has a higher retardation factor than the saturated
zone. A record of this calculation was not provided in the
documentation.
Following migration/ the initial chemical concentration in the
infiltrating water (Cw) is calculated from the initial
concentration of chemicals in the soil mass using the following
relationship:
cw= ^_
where: Cw « initial chemical concentration in water (mg/1)
Cs = chemical concentration in soil (mg/kg)
Kg = partition coefficient [(mg/l)/(mg/kg)]
The equations below were developed to analyze a "batchwise"
extraction of chemicals by percolating water from a soil column
divided into several cells of equal size. Cell size is
determined by factors such as location of cell (i.e./ saturated
or unsaturated zone) and the limitations of the computer used
to run the model. The equations assume that mobile water is
replaced by clean water and the system reaches equilibrium with
each successive percolating cycle.
The concentration of chemicals leaving the first cell can be
expressed as:
-w
(KdMs + Mwg)
Mw
where: Cw = concentration of chemicals in water after wetting
(mg/1)
Ms = mass of soil per unit volume of soil (kg)
Mw = mass of water per unit volume of soil assuming
50% moisture content (kg)
a = fraction of immobile water
80
-------
The chemical concentration in the water leaving the second cell
can be expressed as:
Cw2 = Cw2*
Mw> ~ CwlMw(l-a)
Mwa
where: Cw2 = concentration of chemicals in water leaving
cell 2 (mg/1)
Cwi = concentration of chemicals in water entering
cell 2 from cell 1 (mg/1)
Cw2* = concentration of chemicals in water in cell 2
after one pore volume flush (mg/1)
Water leaving cell 2 enters cell 3. This methodology, as
mentioned earlier, uses a "batchwise" extraction of chemicals
from a soil column. The resulting chemical concentration
leaving the last cell is the concentration at the
unsaturated-saturated boundary.
Upon entering the saturated zone the chemical concentrations
are attenuated by the higher flow rates. The method also
assumes that total mixing of chemicals occurs as water is
leached out of the unsaturated zone. The amount of attenuation
is calculated by using relative flow rates and chemical
concentrations entering and leaving a control volume.
CHt =
_ (Qin)H CH + (Qin)v Cv
(Qin)H + (Qin)v
where:
CH
(Qin)H
resulting attenuated chemical concentration in
the saturated zone (mg/kg)
initial chemical concentration in the saturated
zone (mg/kg)
flow rate entering the control volume in
horizontal direction, from the unsaturated zone
U3/t)
(Qin)v = flow rate entering the control volume in the
vertical direction; from the unsaturated zone
(13/t)
Cv = chemical concentration entering the control
volume vertically from the unsaturated zone (mg/kg)
Two additional calculations are needed, percolation rate and
dilution factor, to complete the evaluation of the chemical
concentration in the unsaturated zone compared to the estimated
chemical concentration in the aquifer.
81
-------
The percolation fraction of precipitation is the principle
contributor to chemicals leaching from the unsaturated zone. The
equation to calculate monthly water balance or mean percolation is
PERC = P - R/O - AST - AET
where: PERC = mean monthly percolation (ft/yr)
P » mean monthly precipitation or rainfall (1)
R/O = mean monthly runoff (1)
AST « change in soil moisture storage (1)
AET = actual evapotranspiration (1)
The last measurement needed to compute the expected aquifer
concentration is the dilution factor (DF)/ which is defined:
(OinW
DF = [Qin)H +
-------
Total mixing of chemicals upon leaving unsaturated zone is
assumed
- Batchwise system assumes soil column is flushed with clean
water.
Case Studies;
Intel, CA; Rathon, CA; and Fairchild, CA - collectively known as
the Mt. View, CA, site.
83
-------
Title: Ground Water Contamination from Sewage Sludge
Source; 40 CFR parts 257 and 503, Monday/ February 6, 1989/
Standards for the Disposal of Sewage Sludge; Proposed Rule,
Data Requirements/Processes Addressed;
- Electromotive potential of soil
- pH of onsite soil
Leachate pulse rate (years)
- Metal concentration in sludge (mg/kg)
- Sludge solids content (kg/1)
- Fill thickness (meters)
- Assumed leachate concentration
- Ground water recharge rate (m/yr)
- Amount of excess liquid in sludge (1/yr)
84
-------
Model Description;
EPA has adapted existing models to determine the concentration
of sludge-borne contaminants in ground water. Two waste
application scenarios were considered in the EPA methodology
discussed below:
land applications for agriculture
wastes placed in a sludge-only landfill.
For both application scenarios and subsequent contaminant
pathways a series of mathematical models was used to predict
the contaminant concentration at the point of exposure.
Models/ CHAIN/ MINTEQ, and AT123D were used consecutively to
predict the contaminant flow through the unsaturated zone/ the
unsaturated zone/saturated zone interface and the saturated
zone. Applicable components of these models will be further
described in this summary. Because this compendium addresses
contaminant migration through the unsaturated zone/ only these
evaluation components of this EPA method will be summarized
below.
The leachate concentration formed in the soil layer containing
the sludge is related to the contaminant concentration in the
soil using a partition coefficient. In the unsaturated zone/
the peak leachate concentration is reduced by the modeled
processes of vertical dispersion (primarily caused by detention
of sorbed contaminants), natural chemical degradation, and
metal precipitation. The CHAIN model was used to predict these
processes for organics, and the geochemical model, MINTEQ, for
metals. Factors affecting the contaminant loading rate in the
unsaturated zone include the recharge or infiltration rate/
hydraulic characteristics of the soil, depth to ground water,
and the partition-coefficient. For some metals, the net ground
water electromotive potential (Eh) and pH also influence
precipitation rates.
The exposure pathway examined by EPA was contaminant
infiltration to ground water and subsequent ingestion via
drinking water. The analytical framework for the ground water
model contained four components:
a calculation of contaminated leachate pulse duration
(contaminant release to the unsaturated zone)
a model of contaminant behavior and movement in the
unsaturated zone
an evaluation of metal solubility in ground water
a model of contaminant behavior and movement in the
saturated zone.
The analysis includes assumptions on the size and thickness of
landfills, the concentration of the contaminant in the sludge,
85
-------
the contaminant concentration in the leachate, and the net
recharge or infiltration rate.
First/ the leachate pulse rate or the time in which the
landfill releases a metal pollutant to the unsaturated zone is
calculated for metals:
T = (CS x SS/CL) - EL x D/R
where: T = time (years)
CS = metal concentration in sludge (mg/kg)
SS = sludge solids content (kg/1)
D = fill thickness (meters)
CL = assumed leachate concentration (mg/1)
R = ground water recharge rate (m/yr)
EL = excess liquid in original sludge (1/yr)
The EL term adjusts the recharge water rate based on the sludge
characteristics (i.e., aqueous). The organic contaminants in
the above calculations are modified to account for decay. This
modification is described in the EPA's "Land Application and
Distribution and Marketing of Sewage Sludge." In contrast, the
calculation above assumes that the (CL) leachate concentration
remains constant until the sludge is completely depleated of
the contaminant, thereby modeling the leachate pulse as a
mathematical square wave.
This leachate pulse is subsequently used in the unsaturated
zone CHAIN model. The CHAIN model (Van Genuchten, 1985)
assumes a steady rate of percolation through the unsaturated
zone. This model calculates the contaminant concentrations in
the leachate as affected by sorption to the soil and decay (of
organic contaminants).
These modified leachate pulse levels (i.e., metals, organics)
are further adjusted for solubility constraints, based on the
calculations of MINTEQ (Felmy, 1984). This incorporates the
results of previous runs at various conditions of pH and Eh.
The estimated contaminant leachate entering the aquifer beneath
the monofill is then applied to the saturated zone fate and
transport model, AT123D (Yeh, 1981). This model calculates the
contaminant plume considering advection, diffusion and
dispersion, sorption, decay, and for landfills, the distance
from the sewage sludge unit to the property boundary of the
landfill or 150 meters, whichever is less.
The components of the EPA models (leachate pulse, CHAIN,
MINTEQ, and AT123D) are run through trial and error and to
determine the sludge concentration equal to the MCL or
allowable drinking water standard at the point of compliance.
86
-------
Limitations;
Several uncertainties and assumptions must be considered when
using the model's predictions. These include:
- Sludge pollutants solubilized (leached) if not first
degraded
- Square wave input to ground water
Organic pollutant decay rate
Additional assumptions and derivations to the model is further
discussed in "Landfilling Sewage Sludge/" (US EPA/ 1988).
These identify applications for differing exposure pathways.
Output Parameters of the Model;
Leachate pulse rate (years)
- Contaminant plume dimensions
Leachate contaminant concentrations/ based on sludge
concentrations/ that will be equal to or below MCLs or
allowable drinking water standards
87
-------
-------
GENERIC METHODS
89
-------
Title: Designated Level Methodology
Source; California Regional Water Quality Control Board,
"Waste Classification and Cleanup Level Determination
Draft Guidance Document," Central Valley Region, 1985,
Data Reguirements/Processess Addressed;
- Water quality goals, such as background levels or accepted
criteria and standards
- Environmental attenuation and bioavailability data for
contaminants
90
-------
Model Description;
The California State Water Resource Control Board has
established a waste classification scheme and developed cleanup
criteria based on the threat that these wastes (including
contaminated soil) pose to the beneficial uses of waters of the
State. The designated waste category, comparable to the
California Department of Health Services (DHS) hazardous waste
classification, is described as the level at which a waste
could significantly impair water quality. To more clearly
define the lower boundary of the classification, the Designated
Levels methodology was developed. This methodology was derived
from the California Assessment Manual for Hazardous Waste Final
Statement of Reasons (CAM SOR), for the Hazardous Waste
Identification Regulations adopted by DHS in 1984.
The Designated Level methodology was developed to provide a
means for determining if a solid waste is hazardous and the
appropriate type of waste management unit. Because
contaminated soil and wastes in an unlined landfill, surface
impoundment or waste pile pose a similar threat to water
quality, the Designated Level methodology also can be used to
establish contaminated soil cleanup levels. By using this
methodology, soil brought to a cleanup level at or below the
Designated Level calculated for a particular contaminant can be
considered protective of nearby surface or ground water quality.
Designated Levels can be calculated for specific contaminants
and at specific sites by determining appropriate water quality
goals, such as background water concentrations or accepted
criteria and standards, and then applying factors to account
for environmental attenuation and bioavailability. Contaminant
concentrations that are less than these calculated levels are
not considered to be a detriment to the beneficial uses of the
waters of the State, and, therefore, can be disposed in an
unlined landfill. Wastes containing contaminant concentrations
in excess of the Designated Levels are classified as
"designated wastes" and must be disposed of in a waste
management unit that isolates them from the environment (e.g.,
lined landfill). Designated wastes have the potential to be
mobilized and transported to ground and/or surface waters in
amounts that could degrade the quality of those waters.
The attenuation factor chosen for the Designated Level
methodology is the one recommended by the CAM SOR. It is a
100-fold attenuation factor and is based on studies conducted
by Battelle Laboratories and the U.S. EPA. The EPA study used
a mathematical model in formulating its 100-fold factor,
examining attenuation factor data from several known disposal
sites ranging in values from 4 to greater than 1,000 for
91
-------
various toxic substances. Both studies indicate that the
degree of attenuation is dependent on the chemical properties
of the waste constituents, distance from the waste management
unit to usable water/ the geologic materials including the;
permeability/ chemistry and structure/ and the velocity of
ground or surface water. Therefore/ it would be difficult to
select a factor that would be appropriate for all contaminants
and disposal situations. A factor of 100 is considered to
conservatively represent average attenuation of waste
contaminants as they leach from soil into ground water. Where
site conditions indicate the probability of limited
attenuation/ such as highly permeable soil or shallow depth to
ground water/ an attenuation factor less than 100 should be
used. In the case where contaminants exhibit a strong capacity
for attenuation, a factor higher than 100 should be chosen.
For example/ the Designated Level Methodology uses a 1,000-fold
attenuation factor for copper, zinc, and DDT because these
constituents are known to be highly immobile in soil.
Note that specific attenuation factors are not assigned for
individual contaminants. Decisions to adjust the attenuation
factor are based on assumptions pertaining to contaminant and
site characteristics.
Water Quality goals to be used in deriving Designated Levels
can come from several sources. Background water quality, is an
appropriate goal in some cases/ however/ there are many sources
of numerical criteria which were established to protect human
health and the environment. A list containing several of these
sources can be found in Appendix E.
Designated Levels for contaminated soils can be expressed as
Soluble or Total. The extractable or soluble fraction of a
contaminant in soil is what actually has the potential for
migration; therefore/ the Soluble Designated Level (SDL) more
accurately measures the ability of a contaminated soil to
degrade water quality. When calculating the SDL/ it is assumed
that by the time the leachate reaches and combines with ground
water/ the concentrations of soluble constituents have been
diminished by a factor equal to the environmental attenuation
factor (i.e./ 100, 1000). Additionally/ the concentrations in
the initial leachate is assumed to be equal to the extractable
concentration in the contaminated soil prior to leaching.
Thus/ the SDL can be expressed in mg/kg as:
Soluble = Environmental x Water Quality
Designated Level Attenuation Factor Goal (mg/1)
(mg/kg of waste)
92
-------
The extractable or soluble fraction of a contaminant in a soil
or solid waste sample can be obtained by performing a leachate
extraction procedure on the sample. The California Waste
Extraction Test (WET) is the leachate test procedure
recommended for this method. (For a detailed description of
the WET, see Appendix C). It requires a ten-fold dilution of
solid waste into a buffered citric acid extract solution,
resulting in a concentration of 1 mg/1 of extract that is
equivalent to 10 mg/kg of waste. The SDL, expressed as mg/1 of
extract, is equal to one tenth the SDL expressed as mg/kg of
waste:
Soluble Designated Level = Soluble Designated Level
(mg/1 of extract) (mg/kq of waste)
10
Environmental
Attenuation Factor
10
Water Quality
Goal (mg/1)
It is important to note that other leachate test procedures may
not require the same amount of dilution as in WET, and,
therefore, a different dilution factor would be used in the
equation above.
Total Designated Levels (TDLs) should be calculated when
extractable contaminant concentrations in a soil cannot be
determined but total contaminant concentration analysis in a
soil is possible. The results of the total concentration
analysis is compared to the TDL for a specific contaminant to
determine if the degree of contamination in the soil is
exceeding the recommended cleanup level. TDLs can be derived
from SDLs by applying a bioavailability factor that represents
the soluble fraction of the total contaminant concentration
which can move into the leachate and migrate to ground or
surface waters. This methodology employs a generic
bioavailability factor of 100 for inorganic constituents and 10
organic constituents. Note that bioavailability factors should
be adjusted to compensate for site or chemical specific
conditions. For instance, a higher bioavailability factor may
be appropriate if the physical and chemical properties of a
particular contaminant decreases the potential for leaching.
TDLs are expressed in mg/kg of waste as:
Inorganics:
Organics:
Total
Designated Level = 100 x
(mg/kg of waste)
Total
Designated Level = 10 x
(mg/kg of waste)
Soluble
Designated Level
(mg/kg of waste)
Soluble
Designated Level
(mg/kg of waste)
93
-------
When using SDLs expressed in mg/1 of extract/ due to the
10-fold dilution in WET/ the attenuation factors above would
be: inorganic/ 1000; and organic/ 100. Here again, the
dilution factor depends on the amount of dilution used in the
leachate extraction procedure selected.
Another component of the Designated Level Methodology for
determining contaminated soil cleanup levels is consideration
of cumulative environmental/health effects. When several
contaminants with similar properties or toxicologies are
present/ it is presumed that their effects are additive. The
contaminated soil can be considered to meet the appropriate
cleanup levels if the sum of the quotients (obtained by
dividing the concentration of each contaminant identified and
its recommended Designated Level) is less than one. This
equation is expressed as:
n (chemical concentration)i
Z < 1.0
i=i (chemical Designated Level)i
Calculating cumulative effects is a more conservative method
for determining soil cleanup levels because it considers more
than one contaminant in the soil. This is demonstrated by the
fact that the sum of the quotients in the equation above can be
greater than one and/ therefore/ it exceeds the recommended
cleanup level even if each contaminant is below its individual
Designated Level.
The method used to determine the appropriate soil performance
goal may be selected based on several factors. These include
the frequency and type of contaminants (i.e./ VOCs/
inorganics), geologic characteristics and estimated risk at the
site.
Limitations:
- Site-specific considerations not addressed in detail.
Case Studies:
PG&E-Caribou Power House, PCB spill/ Plumes County/ CA;
Lawrance Livermore National Laboratory/ Nameda/ CA; and
Southern Pacific/ Roseville/ Placid County, CA.
94
-------
Title; Acceptable Soil Contamination Levels
Source: New Jersey Department of Environmental Protection,
"Acceptable Soil Contamination Levels Methodology," In
Inventory of Criteria and Methods to Select Criteria.
(Unpublished Report), G.M. Richardson, Environment
Canada, 1987.
Data Requirements/Processes Addressed;
For organic contaminants, certain site-specific
characteristics, including soiltwater partition
coefficients; measures of chemical mobility, erosion, and
topography
EPA water quality criteria, drinking water standards, acute
toxicity or other data for organic contaminants.
95
-------
Under the Environmental Cleanup Responsibility Act (ECRA) / the
New Jersey Department of Environmental Protection has
determined Acceptable Soil Contamination Levels (ASCLs) for 11
metals and 4 classes of organic compounds. The goal of these
soil criteria is to protect ground water quality. Acceptable
levels of inorganic contaminants represent simple multiples of
background levels of these contaminants in New Jersey or other
U.S. soils.
Acceptable concentration levels of organic compounds are
obtained by using a system that addresses the three media;
soil/ ground water and surface water. The system includes the
prediction of contaminant distribution between the three types
of media using certain site-specific characteristics/ including
soil:water partition coefficients, measures of chemical
mobility, erosion/ and topography. These characteristics are
combined with EPA water quality criteria, drinking water
quality guidelines and acute toxicity or other data to
calculate ASCLs which are then used to guide cleanup. In the
absence of data required to determine ASCLs for organics, the
following surrogate or action levels are used: volatile
organics - 1 ppm total in soil; base/neutrals - 10 ppm total in
soil; petroleum hydrocarbons - 100 ppm total in soil (except
benzene and PAHs) .
This method is simple, requires a minimal amount of input data,
and focuses primarily on soil contamination.
The method does not address multi-contaminant and multimedia
exposure/ or inhalation or dermal exposure to contaminants.
Case Studies;
Burnt Fly Bog, NJ (for lead and PCBs only)
Ringwood Mines, NJ (lead and arsenic)
96
-------
Title: Maximum Exposure Dosage (MED 200)
Source; Contaminated Soils Workgroup Preliminary Findings and
Recommendations, (Draft)/ Maximum Exposure Dosage (MED
200) Methodology.
Data Requirements/Processes Addressed;
EPA drinking water standards for metals and pesticides.
97
-------
Method Description:
The MED 200 method is designed for use by the Emergency
Response Team (ERT) and the individual EPA Regions for
emergency actions. It involves the removal of onsite soils
until metals or pesticides are at 200 times drinking water
standards (e.g./ chromium standard would be 10 ppm for soils).
This approach assumes that it is unlikely that metals or
pesticides would contaminate ground water at significant levels.
One advantage of this method is that direct contact threats are
addressed because contaminants posing potential immediate
hazards are removed. It also considers ground water protection
through use of drinking water standards. In addition/
analytical results can be obtained simply and quickly because
the method involves only a total contaminant concentration
analysis and does not include time intensive procedures such as
the gathering of site-specific soil and hydrogeologic
information required when conducting fate and transport
modeling.
Limitations;
- Potential for overprotective measures in many situations
- Parameters such as low mobility are not considered
- Does not address contaminants other than metals and
pesticides.
Case Studies;
This method is used exclusively as a reference tool to
establish soil cleanup levels and supported by additional
site-specific parameters such as risk factors and exposure
levels.
98
-------
Title: Technical Cleanup Policy
Source; Washington State Department of Ecology/
"Standard/Background Cleanup Level and Protection
Cleanup Level Methodologies," In Inventory of Cleaning
Criteria and Methods to Select Criteria. (Unpublished
Report), G.M. Richardson, Industrial Programs Branch,
Environment Canada, 1987.
Data Requirements/Processes Addressed;
Standard or background levels for contaminants, such as
drinking water or water quality standards, water quality
background levels, and/or soil background levels
- Certain site-specific data, including contaminant,
hydrologic, and soil characteristics.
99
-------
Method Description;
The Cleanup Policy developed by the State of Washington is
based on three types of cleanup levels: initial/
standard/background, and protective cleanup levels for soil/
surface water/ ground water/ and air. Cleanup criteria are
based on existing environmental standards such as EPA Water
Quality Criteria or drinking water guidelines; in the absence
of appropriate standards/ criteria are based on background
levels of contaminants. Initial cleanup levels are intended to
eliminate all imminent threats to public health and the
environment/ and to eliminate situations where a delay will
increase the difficulty of cleanup.
Remedial options include total cleanup, partial cleanup/ site
stabilization/ or a combination of partial cleanup and site
stabilization/ depending on the site conditions. Standard/
background cleanup levels are applied to all sites where an
initial total cleanup option is not implemented; these cleanup
levels are intended to eliminate any potential chronic threat
to public health or the environment. Standard/background
cleanup levels for soil are 10 times the drinking water or
water quality standards/ 10 times the water quality background
levels/ or equal to the soil background levels. If
standard/background cleanup levels are not appropriate or can
not be achieved/ the site is subjected to soil Protection
Cleanup Levels or the maximum acceptable concentration of soil
contamination at the source/ that are derived either from
existing standards or from predictive models (types of models
unspecified)/ using site-specific data.
For contaminated soil that is a potential threat to surface or
ground water quality/ Protection Cleanup Levels are designated
100 times the drinking water or water quality standards/ 100
times the water quality background levels, 10 times the soil
contaminant background levels, or are defined based on
site-specific contaminant and soil characteristics/ leaching
tests or biologic tests. If sufficient site-specific input
data are available/ predictive models, including HELP and
SUTRA, may be used to determine soil Protection Cleanup Levels
as follows.
First/ the maximum acceptable level of contamination in the
ground water directly underlying the contaminant source is
defined/ using the appropriate water quality standards or water
quality background levels/ biologic testing/ or the ground
water protection level (the maximum acceptable concentration in
the ground water). Next/ the maximum acceptable concentration
gradient is defined with verified transport models/ using
site-specific contaminant/ hydrologic/ and soil
characteristics; the concentration gradient is then used to
determine the soil Protection Cleanup Level.
100
-------
Limitations;
This method is limited to use at sites contaminated with
chemicals for which environmental standards exist. In
addition, the method does not address multi-contaminant and
multimedia exposure.
Case Studies;
This method is used as an initial site evaluation tool and has
not been used as an exclusive source to establish soil cleanup
levels.
101
-------
-------
BIBLIOGRAPHY
1) American Conference of Governmental Industrial Hygenists,
"Documentation of the Threshold Limit Volumes/" 4th ed./
American Conference of Governmental Industrial Hygenists,
Cincinnati/ OH, 1980
2) Bates/ R.L. and J.A. Jackson, eds., Dictionary of
Geological Terms, 3rd Ed. Anchor Press/Doubleday, Garden
City, NY, 1984.
3) Brady/ N.C./ The Nature and Properties of Soils. 9th Ed./
Macmillan, New York, NY, 1984.
4) Briggs, G.G., R.H. Bromilow, A.A. Evans, "Relationships
Between Lipophilicity and Root Uptake and Translocation of
Non-ionized Chemicals by Barley", Pesticide Science, 13,
pp. 495-504, 1982.
5) Bulman, T.L., K.R. Hosier, B. Ibbotson, D. Hockley, and
M.J. Riddle, "Aid for Evaluating the Redevelopment of
Industrial Sites (AERIS) Model", In Development of a Model
to Set Cleanup Criteria for Contaminated Soil at
Decommissioned Industrial Sites. Environment Canada, Senes
Consultants Ltd. and Moneco Consultants Ltd., Canada, 1988.
6) California Department of Health Services - Toxic Substance
Control Division, Site Mitigation Decision Tree Manual,
1986.
7) California Regional Water Quality Control Board, "Waste
Classification and Cleanup Level Determination Draft
Guidance Document", Central Valley Region, 1985.
8) CH2M Hill, "Soil Contaminant Evaluation Methodology
(SOCEM I)", In Guidance on Remedial Actions for
Contaminated Soils at CERCLA Sites. (Draft), Groundwater.
May-June edition, 1985.
9) Clapp, R.B. and G.M. Hornberger, "Empirical Equations for
some Hydraulic Properties", Water Resources Research,
V. 14, pp. 601-604, 1978.
10) Cleland, J.G., G.L. Kingsbury, "Mutimedia Environmental
Goals for Environmental Assessment," Vol. I, EPA
600/7-77-136a, Environmental Protection Agency, Washington,
DC, pp. 60-61, November 1977
11) Contaminated Soils Workgroup, "Preliminary Findings and
Recommendations (Draft)", Background Levels Methodology.
103
-------
12) Contaminated Soils Workgroup/ "Preliminary Findings and
Recommendations (Draft)", Exposure Assessment Using
Leachate Tests Methodology.
13) Contaminated Soils Workgroup/ "Preliminary Findings and
Recommendations (Draft)", Maximum Exposure Dosage (MED 200)
Methodology.
14) Contaminated Soils Workgroup, "Preliminary Findings and
Recommendations (Draft)", Visibly Contaminated Soils
Methodology.
15) Dragun, J., The Soil Chemistry of Hazardous Materials.
Chapter 6, Table 6.4 1988.
16) Felmy, A.R., D.C. Girvin and E.A. Jenne, "MINTEQ - A
Computer Program for Calculating Aqueous Geochemical
Equilibrium", EPA-600/3-84-032, 1984
17) Fetter, C.W. Jr., Applied Hydroqeology. Charles E.
Merrill/Bell and Howell, Columbus, OH, 1980.
18) Fitchko, J., Criteria for Contaminated Soil/Sediment
Cleanup. 1989
19) Freeze, R.A. and J.A. Cherry, Groundwater. Prentiss Hall,
Englewood, NJ, 1979.
20) Holt, G.A., C.C. Travis, E.L. Etnier, C. Cook, F.R.
O'Donnell, D.M. Hedrick and E. Dixion. "Multiple Pathway
Screening - Level Assessment of a Hazardous Waste
Incineration Facility," ORNL/TM-8652, Oak Ridge National
Laboratory, Oak Ridge/ Tennessee, 1984.
21) Hunt, B., "Dispersive Sources in Uniform Groundwater Flow",
Journal of the Hydraulics Division, ASCE, V. 104,
pp. 75-85. 1978.
22) IGF/Clement Associates, "Final Focused Feasibility Study -
Independent Nail Company Site - First Operable Unit",
Beaufort, South Carolina, 1988, DC #237-FSl-RT-FSAC.
23) Neiburger, M., J.G. Edinger, and W.D. Bonner, Understanding
Our Atmospheric Environment. 2nd Ed., W.H. Freeman and Co.,
San Francisco, CA, 1982.
24) New Jersey Department of Environmental Protection,
"Acceptable Soil Contamination Levels Methodology", In
Inventory of Criteria and Methods to Select Criteria.
G.M. Richardson, Environment Canada, 1987.
104
-------
25) Rosenblatt, D.H., J.C. Dacre and D.R. Cogley, "An
Environmental Fate Model Leading to Preliminary Pollutant
Limit Values for Human Health Effects", In Environmental
Risk Analysis for Chemicals. Chapter 15, pp. 474-505, 1982.
26) Rosenblatt, D.H., M.J. Small and R.J. Karnz, "Application
of the Preliminary Pollutant Limits (PPLV) Environmental
Risk Assessment Approach to Selected Land Users", In Fate
of Chemicals in the Environment. ACS Symposium Series,
Washington, B.C. 1983.
27) Salee, Mark A. (Memo), Land Disposal Branch, USEPA, to
Kenneth A. Shuster, Chief of Land Disposal Branch USEPA,
Oct. 24, 1984.
28) Sanders, J.E., Principle of Physical Geology. John Wiley &
Sons, New York, NY, 1981.
29) Summers, K., S. Gherini and C. Chen, Tetra Tech Inc.,
"Methodology to Evaluate the Potential for Groundwater
Contamination from Geothermal Fluid Releases",
EPA-600/7-80-117, 1980.
30) Synder, W.S., "Report of the Task Group on Reference Man",
International Commission on Radiological Protection.
No. 23, New York, Pergamon Press, 1975.
31) U.S. Army, "Single Pathway Preliminary Pollutant Limit
Values and Preliminary Pollutant Limit Values (SPPPLV and
PPLV)", In Inventory of Cleaning Criteria and Methods to
Select Criteria. An unpublished document, G.M. Richardson,
Industrial Programs Branch, Environment Canada, 1987.
32) U.S. Congress, Office of Technology Assessment, "Superfund
Strategies for Setting Cleanup Goals," In Inventory of
Cleanup Criteria and Methods to Select Criteria.
G.M. Richardson, Environment Canada, 1987.
33) U.S. EPA, "Evaluating Cover Systems for Solid and Hazardous
Waste", EPA SW-867, 1982.
34) U.S. EPA, "Guidance for Establishing Target Cleanup Levels
for Soils at Hazardous Waste Sites", Office of Health and
Environmental Assessment, Washington, D.C., 1988.
35) U.S. EPA, Interactive Simulation of the Fate of Hazardous
Chemicals During Land Treatment of Oily Wastes; RITZ
User's Guide. Robert S. Kerr Environmental Research
Laboratory, Ada, OK, 1988.
36) U.S. EPA, "National Interim Primary Drinking Water
Regulations", Federal Register 40, pp. 59565-59588.
December 24, 1975.
105
-------
37) U.S. EPA7 Office of Solid Waste, OSW Studies and Methods
Branch Model, In Attachment A of Summary of Remedial
Alternative Selection. McKin Company Site-Gray. ME;
Analysis of Property Boundary Contaminant Concentrations.
Camp, Dresser and McKee, 1985.
38) U.S. EPA, "Radionuclide Interactions with Soil and Rock
Media", EPA report 5206-78-007, Vol. 1, 1987.
39) U.S. EPA, "Technical Support Document: Landfilling of
Sewage Sludge" (Draft), Washington, DC, 1988
40) U.S. EPA, Technical Support Document: Land Application and
Distribution and Marketing Sewage Sludge (Draft). Office
of Waste Regulations and Standards, Washington, DC, 1988.
41) U.S. EPA, "Waste Quality Criteria Documents: Availability
45 Federal Regulations 79318-79379", U.S. Environmental
Protection Agency, Washington, D.C. 1980.
42) Van Genuchten, M., "Convective-Dispersive Transport of
Solutes Involved in Sequential First-Order Decay
Reactions", Journal of Computer Geoscience, Vol. 11 (129)
(CHAIN), 1985.
43) Vettorazzi, G., "The Evaluation of Toxicological Data for
the Protection of Public Health;" Proceedings Inst. Colloq.
Commission of the European Committee; Luxenburg, pp.
207-223, 1976.
44) Washington State Department of Ecology, "Standard/
Background Cleanup Level and Protection Cleanup Level
Methodologies", In Inventory of Cleaning Criteria and
Methods to Select Criteria. G.M. Richardson, Environment
Canada, 1987.
45) Williams, J.R., T.E. Short, C.L. Eddington and C.G.
Enfield, "Contaminant Transport and Fate in Unsaturated
Porous Media in the Presence of Both Mobile and Immobile
Organic Material", (Draft), U.S. EPA, Robert S. Kerr
Environmental Research Laboratory, Ada, OK, 1988.
46) World Health Organization, "Evaluation of the Toxicity of a
Number of Antimicrobials and Antioxidants", Sixth Report of
the Joint FAO/WAO Expert Committee on Food Additives, WHO
Tech, Rep. Ser. No. 228, pp. 9-11. 1962.
47) Yeh, G.T., "AT123D: Analytical Transient One-, Two-, and
Three- Dimensional Simulation of Waste Treatment in the
Aquifer System", Oak Ridge National Laboratory,
Environmental Sciences Division, Oak Ridge, TN, ORNL-5602
1981. '
106
-------
POTENTIAL REFERENCES
;-' ""'.
Anderson, P.F., C.R. Faust, and J.W. Mercer, "Analysis of
Conceptual Designs for Remedial Measures at Lipari Landfill,
NJ", Ground Water V. 22, No. 2, pp. 176-190, 1984.
Assink, J.W., and W.J. Van der Brink, eds., "Contaminated
Soil", In Proceedings from the First International TNO
Conference on Contaminated Soil, November 11-15, 1985, Utrecht,
The Netherlands, Dordrecht, The Netherlands, Martinus Nijhoff
Publishers, 1986.
Baehr, A.L., "Selective Transport of Hydrocarbons in the
Unsaturated Zone Due to Aqueous and Vapor Phase Partitioning",
Water Resources Research, V. 23 No. 10, pp. 1926-1938, 1987.
Brown, H.S, "A Critical Review of Current Approaches to
Determining "How Clean is Clean" at Hazardous Waste Sites",
Hazardous Waste and Hazardous Materials, 3(3) pp. 233-260, 1986.
Brown, K.W., "Monitoring the Unsaturated Zone" In Land
Treatment; A Hazardous Waste Management Alternative. Water
Resources Symposium Number Thirteen, Centre for Research in
Water Resources, The University of Texas at Austin, Texas, 1986.
Bond, F.W., C.R. Cole, and P.J. Gutkecht, "Unsatured
Groundwater Flow Model (UNSATID) Computer Code Manual", EPRI
CS-2434, Electric Power Research Institute, Palo Alto,
California, 1982.
Caupp, C.L., W.J. Grenney and P.J. Ludvigsen, "VIP: A Model
for the Evaluation of Hazardous Substances in the Soil, Version
2", Department of Civil and Environmental Engineering, Utah
State University, Logan, Utah, 1987.
Collins, J.O. and P.C. LeClare, "Risks, Costs and Public
Policy: Determining Acceptable Cleanup Levels", In Conference
on Management of Uncontrolled Hazardous Waste Sites, pp.
398-400, 1983.
Dacre, J.C., D.H. Rosenblatt and D.R. Cogley, "Preliminary
Pollutant Limit Values for Human Health Effects", Evironmental
Science and Technology, 14(7), pp. 778-784, 1980.
Dass, P., G.R. Tamke, and C.M. Stoffel, "Leachate Production at
Sanitary Landfills", Journal Environmental Engineering
Division, Proceedings of the American Society of Civil
Engineers, V. 103, No. EE6, 1977.
Dawson, G.W. and D. Banning, "Exposure - Response Analysis for
Setting Site Restoration Criteria", In Proceeedings of the
National Conference on Management of Uncontrolled Hazardous
Waste, pp. 386-389, 1982.
107
-------
Dime, R. and W. Greim/ "Calculation of Cleanup Levels for
Contaminated Soils"/ Hazardous Sites Mitigation Administration/
New Jersey Department of Environmental Protection/ 1986.
Fenn, D.G./ K.J. Hanley/ and T.V. Degeare/ "Use of the Water
Balance Method for Predicting Leachate Generation from Solid
Waste Disposal Sites"/ SW-168/ U.S. Environmental Protection
Agency/ Washington/ D.C./ 1975.
Gelhar/ L.W. and C.L. Axness/ "Three-Dimensional Stochastic
Analysis of Macrodispersion in Aquifers"/ Water Resources
Research/ V. 19/ No. I/ pp. 161-180, 1983.
Grisham/ J.W./ -ed./ Health Aspects of the Disposal of Waste
Chemicals. New York/ Pergamon Press/ 1986.
Hwang/ S.T./ Technical Support Document Mathematical Model
Selection Criteria for Performing Exposures Assessment;
Airborne Contaminants from Hazardous Waste Facilities, Office
of Health and Environment Assessment, Office of Research and
Development, U.S. EPA, Washington, D.C., 1986.
Ibbotson, E.G., D.M. Gorber/ D.W. Reades, D. Smyth, I. Munro,
R.F. Willes, M.G. Jones/ G.C. Granville/ H.J. Carter and C.E.
Hailes, "A Site-Specific Approach for the Development of Soil
Clean-up Guidelines for Trace Organic Compounds"/ In
Proceedings for the 2nd Conference on Environmental and Public
Health Effects of Soils Contaminated with Petroleum Products.
University of Massachussets/ Amherst/ Massachusetts/ 1987.
Jaber/ H.M./ e_£ .§_!., "Data Acquisition For Environmental
Transport and Fate Screening For Compounds of Interest to the-
Office of Emergency and Remedial Response"/ U.S. EPA,
Washington/ D.C./ EPA 600/6-84-011/ 1984.
Kenaga/ E.E./ and C.A.I Goring/ "Relationship Between Water
Solubility, Soil Sorption, Octanol-Water Partitioning, and
Concentration of Chemicals in Biota", Aquatic Toxicology,
American Society for Testing and Materials, ASTM STP 707,
pp. 78-115, 1980.
Life Systems, Inc./ Toxicology Handbook: Principles Related to
Hazardous Waste Life Investigations. U.S. EPA, 1985.
Lyman, W., W. Reehl, and D. Rosenblatt/ Handbook of Chemical
Property Estimation Methods. McGraw-Hill/ New York, 1982.
Moghissi, A.A./ R.R. Marland, F.J. Congel/ and K.F. Eckerman/
"Methodology for Environmental Human Exposure and Health Risk
Assessment"/ In Dynamics. Exposure, and Hazard Assessment of
Toxic Chemcials. Ann Harbor Science, Chapter 31, 1980.
108
-------
National Research Council, Testing for Effects of Chemicals on
Ecosystems. Washington, D.C., National Academy Press, 1981.
Neely, W.B. and G.E. Blau, Environmental Exposure from
Chemicals. CRC Press Inc., Boca Raton, Florida, V. 1, V. 2,
1985.
Nofziger, D.L., J.R. Williams and T.E. Short, "Interactive
Simulation of the Fate of Hazardous Chemicals During Land
Treatment of Oily Wastes", RITZ User's Guide, Robert S. Kerr
Environmental Research Laboratory, USEPA, Ada, OK, 1987.
Parino, W., et al., "Evaluation and Selection of Models for
Estimating Air Emissions from Hazardous Waste Treatment,
Storage and Disposal Facilities", GCA Corporation Report No.
GCA-TR-82-82-G, USEPA, 1983.
Polcyn, A.J. and H.E. Hesketh, "A Review of Current Sampling
and Analytical Methods for Assessing Toxic and Hazardous
Organic Emissions from Stationary Source," Journal of the Air
Pollution Control Association, V. 35, No. 1, pp. 54-60, 1985.
Schroeder, P.R., J.M. Morgan, T.M. Walski, and A.C. Gibson,
"The Hydralic Evaluation of Landfill Performance (HELP) Model",
V. 1, EPA/530-SW-84-009, U.S. EPA, 1984.
Shen, T.T. and T.J. Tofflemire, "Air Pollution Aspects of Land
Disposal of Toxic Waste", Journal of Environmental Engineering,
Division of ASCE, V. 106, No. EEI, pp. 211-266, 1980.
Shih, C.S., and H. Bernard, "An Expert System for Hazardous
Waste Site Cleanup, Part I," Hazardous Materials Control,
pp. 19-52, 1988.
Spurr, G., and A. Parker, ed., "Meteorological Factors and
Dispersion," In Industrial Air Pollution Handbook, London, New
York, McGraw-Hill, pp. 123-140, 1978.
Stern, A.C., R.W. Boubel, D.B. Turner, and D.L. Fox,
Fundamentals of Air Pollution. (2nd edition), Academic Press,
Inc., 1984.
The Netherlands, Ministry of Housing, Planning and the
Environment, "Implementation of the Soil Clean-up (Interim)
Act", Soil, Water and Chemical Substances Department, Soil
Branch, pp. 12, 1983.
U.S. EPA, "Development of Advisory Levels for Polychlorinated
Biphenyls (PCBS) Cleanup", EPA/600-6-86/002, U.S. EPA,
Washington, D.C., NTIS PB86-232774, 1986.
109
-------
U.S. EPA, "Development of Risk Assessment Methodology for Land
Application and Distribution and Marketing of Municipal
Sludge/" Office of Health and Environmental Assessment/
Environmental Criteria and Assessment Office, Cincinnati/ OH/
ECAO-CIN-489/ 1987.
U.S. EPA/ "Development of Risk Assessment Methodology for
Municipal Sludge Landfilling," Environmental Criteria and
Assessment Office, Cincinnati, OH, ECAO-CIN-485, 1986.
U.S. EPA, Guidelines on Air Quality Models. OAQPS Guidelines
Series, Research Triangle Park, 1980.
U.S. EPA, "Mathematical Model Selection Criteria for Performing
Exposure Assessments", Groundwater Contaminants from Hazardous
Waste Facilities, Draft Technical Support Document, Exposure
Assessment Group, U.S. EPA, Washington, D.C, 1986.
U.S. EPA, Office of Environmental Processes and Effects
Research, "Simulated Waste Access to Ground Water (SWAG) Data
Base".
U.S. EPA, "RCRA Land Disposal Restriction Model", In Guidance
ofl_Rejmedi.a.l...Actions for Contaminated Soils at CERCLA Sites,
CH2M Hill, 1985.
U.S. EPA, "Superfund Exposure Assessment Manual", (Draft),
Office of Solid Waste and Emergency Response, U.S. EPA,
Washington, D.C., 1987.
U.S. EPA, "User's Manual for the Pesticide Root Zone Model
(PRZM)"/ Release 1, EPA-600/3-84-109. U.S. EPA, Athens, GA,
1984.
U.S. Geological Survey, "Burial Ground Studies at Oak Ridge
National Laboratory", Oak Ridge Tennessee.
U.S. Nuclear Regulatory Commission, Earth Sciences Branch,
Office of Nuclear Regulatory Research, "Unsaturated Flow and
Transport through Fractured Media", Washington, D.C.
Versar, Inc., Air Dispersion Modeling as Applied to Combustion
Point Source Evaluations. (Draft), U.S. EPA, Office of Solid
Waste, March 1987.
Washington Department of Ecology, "Final Cleanup Policy -
Technical Guidelines", 1984.
Yeh, G.T. and D.S. Ward, FEMWATER; A Finite Element Model of
Water Flow Through Saturated-Unsaturated Porous Media.
ORNL-4927, Oak Ridge National Laboratory, Oak Ridge, Tennessee,
1979.
110
-------
APPENDICES
in
-------
-------
APPENDIX A
113
-------
APPENDIX A
Technical Resources
(points of contact for soil and ground water information)
Region 1
Region 2
Region 3
Region 4
Region 5
Region 6
Region 7
Region 8
Region 9
Region 10
Headquarters
Ground Water Forum
John Zannos
Richard Willie
Kevin Willis
Kathy Davies
Mike Towle
Bernie Hayes
Joe Hughart
Doug Yeskis
Ruth Izraeli
Kathleen O'Reilly
Steve Kinser
Jeff Rosenbloom
Rene Fuentes
Bernard Zavala
Ron Wilhelm
Engineering Forum
John Gallagher
Richard Kaplan
Agram "Mike" Fayon
Jeff Winegar
Harry Harbold
Jim Orban
Deborah Griswold
Steve Kovac
Henry Schroeder
John Blevins
John Kemmerer
John Barich
EPA Laboratory Contacts
Robert S. Kerr Environmental Research Laboratory
Ada, OK
Dick Scalf
FTS 743-2308
(405) 332-8800
Environmental Research Laboratory
Athens, GA
Bob Ambrose
FTS 250-3130
(404) 546-3402 or 3130
For additional contacts see the Ground Water Research
Technical Assistance Directory (EPA/600/9-89/048) which can be
obtained from the Center for Environmental Research
Information/ORD, (513) 569-7391 or the Practical Guide for
Assessing and Remediating Contaminated Sites (Draft May 1989)
which can be obtained through Joe Abe, Office of Solid Waste,
475-7371.
114
-------
APPENDIX B
115
-------
APPENDIX B
Glossary Of Terms
Adsorption: the attraction of ions or compounds to the
surface of a solid; soil colloids adsorb large amounts of ions
and water. This process can be reversed and the adsorbed
material recovered by the opposite reaction, called desorption
or stripping and is estimated using K^ affected by organic
content of soil.
Advection: the horizontal movement of mass through a medium.
Biouptake: the uptake of contaminants by biological
organisms (plants and animals).
Bulk density: the weight of an object or material divided by
its volume/ including the volume of its pore spaces.
Specifically, the weight per unit volume of a soil mass that
has been oven-dried to a constant weight at 105°C.
Clapp Hornberger constant: a constant in the equation of
Clapp and Hornberger (1978) relating to the relative saturation
of the soil to the relative conductivity of the soil.^
Climatology: study of the characteristic weather of a
region, particularly regarding temperature and precipitation,
averaged over some significant interval of time.
Conservative substance: A substance that does not undergo
reactions in the environment that would either naturally or
through interaction with other pollutants cause concentrations
to decline.
Darcy velocity: a standard unit of permeability, equivalent
to the passage of one cubic centimeter of fluid of one
centipoise viscosity flowing in one second under a pressure
differential of one atmosphere through a porous medium having
an area of cross section of one square centimeter and a length
of one centimeter,^
Darcy's Law: the relationship that states that the rate of
flow of ground water through a porous material is proportional
to the pressure driving the water and inversely proportional to
the length of the flow path.12
Degradation rate (chemical persistency): the rate at which a
chemical is broken down in the environment by hydrolysis,
photodegradation, or soil metabolism; the length of time that a
parent chemical persists in the environment.
Detectable concentration in water: any concentration of a
contaminant in water that is greater than or equal to the
particular method detection limit.
116
-------
Diffusion: the spreading out of molecules/ atoms/ or ions
into a vacuum, fluid/ or porous medium in a direction tending
to equalize concentrations in all parts of the system.1
Dilution: thinning down or weakening a compound by mixing
with water or other solvents.
Discharge time: the time that would be required for water to
move through an aquifer if the aquifer was an open conduit (see
discharge velocity).
Discharge velocity: an apparent velocity, calculated from
Darcy's law, which represents the flow rate at which water
would move through an aquifer if the aquifer were an open
conduit.12
Dispersion: a system comprised of two phases, one of which
is in the form of finely divided particles distributed
throughout a bulk substance.
Distance to receptor: the distance from the contaminated
soil to a user in the direction of ground water flow.
Distribution coefficient (K^): represents the partitioning
of a contaminant between liquid and solid phases. K^ is a
valid representation of this partitioning only if the reactions
that cause the partitioning are fast and reversible and only if
the isotherm is linear.13
Equilibrium: a balanced condition for a particular
reversible chemical reaction.
Exposure pathway: the passage of a contaminant from the
source of contamination, through the transport media/ to the
exposure point and receptor.
Exposure point: the point at which human contact with a
contaminant occurs, such as a well.
Exposure: human contact with a physical, chemical/ or
biological agent through dermal absorption, inhalation, or
ingestion.
Grain size: size of a soil particle; basis for soil textural
classes.
Half-life: the time period in which half the initial
concentration of a contaminant is degraded, assuming that the
degradation follows first-order or pseudo first-order kinetics.
Heat exchange coefficient: represents the transfer of heat
between two materials or substances.
117
-------
Henry's Law constant: the constant for the partitioning of a
pollutant between the vapor and water phases.24
Humidity gradient: the rate of decrease of the amount of
water vapor in air with distance usually in the direction in
which it decreases most rapidly.17
Hydraulic conductivity: a coefficient of proportionality
describing the rate at which water can move through a permeable
medium.^3
Hydraulic gradient: the change in total head with a change
in distance in a given direction; the direction is that which
yields a maximum rate of decrease in head.12
Hydrolysis: the degradation of a contaminant by chemical
reactions involving water or an aqueous solution.
Hydrophobic contaminants: compounds that do not have a
strong affinity for water.1
Infiltration rate: a soil characteristic determining or
describing the maximum rate at which water can enter the soil
under specified conditions, including the presence of an excess
of water.2
Inorganic complexation: the attachment of a transition-metal
ion to another molecule or ion by means of a coordinate
convalent bond.
Ion exchange: substitution of one ion, either positive
(cation) or negative (anion), for another of the same charge.
Land use: planned or proposed future use of a site.
Lateral dispersivity: distribution or suspension of fine
particles in directions lateral to the flow path of a
dispersion medium, such as contaminants in ground water.
Leaching: the removal of materials in solution from the soil
by percolating water.2
Location: the position of a site with respect to potential
migration of contaminants to ground water.
Longitudinal dispersivity: the distribution or suspension of
fine particles along the flow path of a dispersion medium, such
as contaminants in ground water.
Loss/decay: the degradation of chemicals resulting in a
reduction in the concentration of contaminants in soil or
ground water.
118
-------
Mixing rate: the rate that infiltrate and ground water are
combined.20
Non-toxic threshold level: the "safe" level of a contaminant
that is based on a NOEL (no observable effect level) from
animal toxicity testing in combination with a human safety
factor.
Organic carbon partition coefficient (Koc): soil:water
partition coefficient for a contaminant normalized to the
soil's organic carbon content.13
Organic complexation (chelating): a process in which a metal
ion is bound to nonmetal atoms (e.g./ nitrogen, carbon, or
oxygen) to form a heterocyclic ring having coordinate covalent
bonds.
Oxydation: a reaction in which electrons are transferred
from one atom to another.
Partition coefficient: a mathematical expression to
represent the ratio of a contaminant concentration in each of
two phases (e.g., soil: water).
Photolysis: the degradation of a contaminant by chemical
reactions catalyzed by light.
Porosity (soil): the volume percentage of the total soil
bulk not occupied by solid particles.2
Precipitation recharge: the replenishment of ground water
from infiltration of precipitation. Quantity measured using a
rain gauge and calculating water level changes. -^
Reduction: the acceptance of one or more electrons from
another substance.
Remediation: a measure or solution that resolves a
particular problem of a contaminated site.
Retardation: hinder, delay, or slow the progress of
contaminant migration to ground water.
Risk assessment: the determination of risks associated with
contamination of a site, including exposure assessment,
toxicity determinations (hazard assessment), and the
determination of exposure pathways.
Saturated zone thickness: The width of the zone in which the
voids in the rock or soil are filled with water at pressure
greater than atmospheric. The water table is the top of the
saturated zone in an unconfined aquifer.12
119
-------
Soil moisture (water) potential: a measure of the difference
in the free energy state of soil water and that of pure water.
Technically defined as that amount of work that must be done
per unit quantity of pure water in order to transport
reversibly and isothermically an infinitesimal quantity of
water from a pool of pure water, at a specified elevation and
at atmospheric pressure, to the soil water (at the point under
consideration).2
Source concentration: the concentration of a contaminant in
the soil of a site (i.e., the source of ground water
contamination).
Taste and odor thresholds: the lowest concentration of a
contaminant that can be detected by taste or odor.
Temperature gradient: the rate of decrease of air, water, or
soil temperature with distance, usually in the direction it
decreases most rapidly.17
Transport rates: the rate of movement of a contaminant in a
natural transport medium such as ground water, either as solid
particles or in solution, from one place to another.1
Transverse dispersivity: the distribution or suspension of
fine particles in directions normal to the flow line of a
dispersion medium, such as contaminants in ground water.13 A
derived quantity generally obtained by first deciding on a
contaminant transport model and then adjusting parameters to
match field data.
Unsaturated zone thickness: the width of the zone between
the land surface and the water table, including the root zone,
intermediate zone, and capillary fringe. Value usually
obtained by drilling and analyzing soil cores at various site
locations.12
Vertical dispersivity: the vertical distribution of fine
particles in a dispersion medium, such as contaminants in
ground water.
Void fraction: the volume fraction of void space in a
sediment or sedimentary rock.1
Volatilization: the loss or release of contaminants, in the
gaseous state, from soil or ground water to air.
Water solubility: the mass of a compound that will dissolve
in a unit volume of water under specified conditions.13
120
-------
APPENDIX C
121
-------
APPENDIX C
Leachate Extraction Tests
A number of methods for establishing soil cleanup levels
make use of a leachate extraction test (e.g., Extraction
Procedure (EP) Toxicity, Toxicity Characteristics Leachate
Procedure (TCLP)) to determine the fraction of contaminants in
the soil that are soluble, and thus have the potential to
contaminate ground water. Different approaches' have been taken
to utilize these test values. One approach is to apply EP
Toxicity regulatory levels directly to soil cleanup level
determinations. This is done by setting soil cleanup levels at
the concentration that would result in leachate concentrations
less than the EP Toxicity maximum allowable values. This
approach is based on the presumption that if the contaminated
soil is not a hazardous waste according to RCRA-established
levels/ then it has been cleaned up to an acceptable level.
However/ setting the target level to EP Toxicity levels may not
be adequately protective because concentrations of contaminants
remaining still have the potential to contaminate the ground
water at levels that exceed health-based drinking water
standards.
The preferred approach is to use the EP Toxicity or TCLP
test as soil leaching tests. The assumption is that the
contaminant concentrations found in the laboratory extraction
test leachate are equivalent to the concentrations actually
leaching from the soil. This could be considered an acceptable
application of the leachate extraction test if the cleanup
levels attained are comparable to established health-based
criteria and the ground water is close to the surface.
The EP Toxicity and TCLP tests are based on a pass-fail
hazardous waste evaluation procedure. They were designed as
leaching tests for wastes in a municipal landfill, such that
the leaching potential of a waste can be determined and then
can be disposed of properly. They were not designed to be
applied as "soil leaching tests", and, therefore, several
inherent limitations exist when using the tests for this
purpose. For instance, the tests only address the aqueous
phase of water soluble contaminants. Hydrophobic organic
chemicals in a soil sample that are sorbed on particles would
be removed when the sample is filtered according to the test
procedures, and, therefore, would not be detected. An
additional assumption of the tests, is that all sorption of
contaminants onto soil particles is irreversible. In other
words, it is assumed that contaminants which have not become
soluble after the extraction procedure is conducted will remain
sorbed. Scientific evidence indicates, however, that certain
types of sorption are reversible in a natural soil pore water
system/ but may not be readily desorbed during the extraction
procedure. Another limitation is that the laboratory
extraction tests have not been validated for use on natural
soils that have different chemical and physical properties.
122
-------
This is a concern because no data are available to ascertain
the performance of the test on the wide variety of soil types
that exist at Superfund sites. In addition, some contaminants
such as solvents/ volatile organics or immiscible phase wastes
do not depend on water solubility for transport. Because the
leachate extraction tests are based on the water solubility of
contaminants, test results for these chemicals may not be
valid. Another limitation is a result of the filtering step in
the extraction procedure. The test assumes that only what
passes through a filter is capable of being transported in soil
pore water or ground water systems. Filtering, however, can
remove from the leachate certain contaminants that are
transported by micro particles of organic or mineral origin.
Scientific evidence indicates that contaminants can be
transported through the soil and ground water in this manner.
The most appropriate use of laboratory leachate extraction
tests would be as a first approximation for predicting the
chemical composition of leachate systems in the field. The
remainder of this Appendix describes some of the tests that are
presently available.
Five leachate extraction test procedures are presented here
with a brief description of their methodologies and a
discussion of their appropriate uses and limitations. These
procedures include the Extraction Procedure (EP) Toxicity test,
Toxicity Characteristic Leaching Procedure (TCLP), The
California Waste Extraction Test (WET) and the American Society
for Testing and Materials procedure (ASTM D3987). Also
described is a procedure for determining the net acid
production or neutralization potential in a waste sample, which
can be used to assist in selecting the appropriate leachate
extraction test.
EP Toxicitv Test - The test was developed by EPA to determine
if a solid waste exhibits the EP Toxicity characteristics of a
hazardous waste. A solid waste whose extract contains any of
the EP Toxicity constituents at concentrations equal to or
greater than the designated maximum values, as specified in 40
CFR Part 261.24 Table I, is considered to be EP toxic, and,
therefore, is characterized as a hazardous waste.
To obtain the waste extract, the EP Toxicity test
procedures are used. The liquid and solid components of a
waste sample are separated and the solid portion is added to 16
times its weight of deionized water and agitated for a period
of 24 hours. During the agitation period, the pH level of the
solution is maintained at 5.0 ± 0.2 with a 0.5N solution of
acetic acid, at no more than 4 milliliters of acid per gram of
solid for each addition. The temperature is maintained at
20-40°C. After agitation, the leachate solution is filtered
from the solid portion, and the liquid extracted from the
123
-------
original sample is added to the leachate solution. These
combined liquids then are analyzed for EP Toxicity
constituents. (Refer to 40 CFR Part 261 Appendix II for a more
detailed description of the EP Toxicity Test procedures.)
The EP Toxicity test is a promulgated procedure with
maximum concentration values established for eight metals/ four
pesticides and two herbicides. Therefore, these constituents
would be the ones most appropriate for analysis using this
leachate extraction methodology. When using the EP Toxicity
test to simulate the degree of leaching that actually would
occur from a disposed waste (as opposed to its intended purpose
as a pass-fail waste classification test), analysis of
additional inorganic and non-volatile organic constituents may
be appropriate.
TCLP - This test was developed by EPA to address a
Congressional mandate to identify additional characteristics Of
wastes, primarily organic constituents, that may pose a threat
to the environment. It has been promulgated for use in
determining specific treatment standards associated with the
land disposal restrictions and has been proposed as a
replacement for the EP Toxicity test. The procedure involves
an 18-hour extraction of a sample and uses a different leaching
solution depending on the nature of the waste being tested.
For wastes of low alkalinity, an acetic acid/sodium acetate
buffer solution at a pH of 5.0 is used for extraction. An
acetic acid solution is used for a more alkaline waste. Unlike
the EP Toxicity test, the TCLP can be used for volatile waste
constituents because a zero headspace extraction vessel can be
employed.
This procedure expands the EP Toxicity list of contaminants
from 14 to a total of 52. The additional contaminants include
20 volatile organics, 16 semi-volatile organics and two
pesticides. The regulatory level for these contaminants are
derived from health-based concentration thresholds and
compound-specific dilution/attenution factors developed using a
ground water transport model. Lastly, note that current
regulations are being proposed to modify the TCLP and to expand
the list of constituents to be analyzed by this technique.
(For a more detailed description of the TCLP, refer to 40 CFR
Part 268, Appendix I. The proposed modificaions can be found
in 53 FR 18792.)
California Waste Extraction Test (WET) - The WET is used to
determine extractable concentrations of toxic constituents in a
waste. The acid buffer solution used in the WET is designed to
simulate leaching characteristics which may occur in a
nonhazardous solid waste landfill. A waste sample is added to
a 0.2M sodium citrate solution at pH 5.0 ± 0.1. The solution
is then flushed vigorously with nitrogen gas for 15 minutes to
remove and exclude atmospheric oxygen from the extraction
124
-------
medium. If volatile substances are to be analyzed, the sample
should be added after deaeration with nitrogen to avoid
volatilization loss. The sample is agitated for 48 hours and
maintained at 20-40°C. The extract then is filtered
directly or centrifuged and filtered from the solid portion,
and analyzed. (For a complete description of the WET
methodology, refer to the California Code of Regulations, Title
22, Division 4, Chapter 30, Section 66700.)
The WET is used to determine leachate constituent
concentrations primarily for inorganics, pesticides,
herbicides, PCPs and PCBs. The current procedure is not
designed to accurately determine extractable concentrations for
volatile organics because significant quantities of these
constituents would be lost to the air space in the extraction
vessel during agitation as well as to the atmosphere during
other waste and extract handling phases of the WET. However,
the WET could be used for extracting volatile organics provided
that a Zero Headspace Extraction vessel is used, such as in the
TCLP method.
A citric acid buffer solution is used in the WET to
simulate the potentially acidic environment that the waste may
be exposed to as well as the acidic leachate generated by the
waste itself. In some cases however, it may be appropriate to
use deionized water in the WET to more accurately assess the
leachability of contaminants in wastes that have no acid
generation potential or have sufficient potential to neutralize
all the acid formed in the waste. (Refer to the American
Society for Testing and Materials (ASTM) procedure for an
additional deionized water leachate extraction test method.)
A deionized water extraction also should be used when the
extract is to be analyzed for hexavalent chromium. This is
because in the presence of the acid buffer, chromium (VI) may
be reduced to chromium (III), thus making the analysis for
Chromium (VI) invalid. Additionally, deionized water
extractions are necessary when analyzing the extract for total
dissolved solids or specific conductivity since the acid buffer
can interfere with these analyses.
ASTM D3987 Method
The procedure requires a mixture of solid waste and
deionized water (Type IV reagent water) and an agitation period
of 18 hours at 18-27°C. The mixture ratio used is a volume
of test water equal in milliliters to 20 times the weight in
grams of waste sample (e.g., 70g sample = 1,400 ml water).
After agitation, the leachate solution is separated from the
solid phase by filtration and analyzed.
125
-------
This method has been tested to determine its applicability
to certain inorganic components in the solid waste. It has not
been tested for applicability to organic and volatile
constituents. (For a complete description of ASTM D3987, refer
to the 1988 Annual Book of ASTM (American Society for Testing
and Materials) Standards/ Volume 11.04.)
An appropriate application for this deionized water
leachate extraction procedure is for waste samples that have no
acid generation potential or have the potential to neutralize
acids formed in the waste. Other appropriate applications are
if the extract is to be analyzed for hexavalent chromium/ total
dissolved solids/ or specific conductivity.
Net Acid/Base Potential Procedure
The procedure can be employed to determine if an acidic or
a deionized water leaching solution should be used to extract
the soluble fraction of contaminants in a solid waste sample.
It involves the use of analytical procedures to identify the
acid generation potential (AGP) and the acid neutralization
potential (NP) of a waste. AGP minus NP is a measure of net
acid/base potential (Net ABP). A Net ABP value indicates the
degree of net acid production or net neutralization potential
of a waste. A positive value indicates the likelihood that an
acidic leachate will be formed and a negative value indicates
that an acidic leachate probably will not be formed. Thus/ the
results obtained from this procedure can be used to select the
appropriate leaching solution and leachate extraction test.
An acidic leaching solution is appropriate for any waste
showing a positive Net ABP while a deionized water leaching
solution should be used for wastes having a negative Net ABP.
(For a complete description of AGP and NP analytical procedures
refer to the following: A. Bruynesteyn and D. W. Duncan/
"Determination of Acid Production Potential of Waste
Materials", Paper for B.C. Research, Vancouver, British
Columbia.)
126
-------
APPENDIX D
127
-------
APPENDIX D
Methods for Determining K^ Values
The mobilization, volatilization, and transformation
reactions of a contaminant in the unsaturated zone are due to
the partitioning (adsorption-desorption) of the contaminant to
the phases existing in the zone. These phases include soil,
water, and vapor (soil gas). Soil physical and chemical
properties affect the ability of a chemical to be adsorbed to
soil surfaces. Important in governing the extent to which an
organic contaminant will be adsorbed are specific aspects of
its chemical structure including molecular size,
hydrophobicity, molecular charge, organic molecular fragments
that undergo hydrogen bonding, the three-dimensional
arrangement, interaction of molecular fragments, and molecular
fragments that undergo coordination bonding.
The partition coefficient (K^) mathematically expresses
this partitioning. K^ is an equilibrium constant defined as
the ratio of the contaminant concentrations in each of two
phases (when equilibrium between the two phases has been
reached). At this point, adsorption-desorption of a
contaminant between the particular phases is at an
equilibrium. K^ values are used in modeling contaminant
movement through the subsurface. An underlying assumption to
using K
-------
- Cwater
where;
csoil = contaminant concentration in
soil
cwater = contaminant concentration in
soil water or ground water
Kg = soil:water partition
coefficient
A Kg value can be estimated using a number of sources and
techniques that vary from simply obtaining a value from
scientific literature to constructing an elaborate laboratory
soil column apparatus. The choice of technique depends on the
level of accuracy necessary for the soil cleanup level
methodology in which it will be applied, the amount and
accuracy of required field data, and the availability of time
and funding. Several methods for determining K
= Kom (om)
where;
oc = soil organic carbon content in the soil
om = soil organic matter content in the soil.
The following equation explains the relationship between (om)
and (oc) and is assumed to be constant;
KOC = 1*724 (Kom)
Koc or Kora values can be used directly as the K^
value for a specific contaminant if the necessary soil data are
not available, however, a more accurate estimation can be
obtained when adjusting the values with the organic matter
content of the contaminated soil in question. (The EPA
publication, "Evaluating Cover Systems for Solid and Hazardous
Waste", EPA SW-867, September 1982, contains a table estimating
percent organic matter typically found in soils.) Thus, an
129
-------
estimation for K by James Dragun, Ph.D. (Chapter 6, Table
6.4). In the book are listed 14 equations that can be used to
estimate Koc or Kom. These equations are based on two
empirical measurements of organic chemical hydrophobicity:
water solubility/ and the octanol-water partition coefficient,
which are readily available in literature sources for most
organic chemicals. The estimation equations were derived on
the basis that water is the primary solvent in the soil
system. Listed with the equations are the organic chemicals
that were used to develop each equation. Also included for
each equation is a range of soil organic carbon or organic
matter content within which the equations are valid.
The author points out the fact that these equations are not
universally applicable to all organic chemicals in all soil
systems and should not be used without regard to their
limitations (e.g., applicable for contaminants with molecular
weights less than 400). These limitations can be found in the
text and should be thoroughly reviewed prior to using the
equations to determine a K
-------
contaminant concentration in solution no longer decreases.
This is the point where it is assumed that an equilibrium
condition has been reached.
The batch experiment is considered to be a fairly effective
method for determining a Kg, however, it is more reflective
of a laboratory-derived value. The agitation technique used to
attain equilibrium exposes a larger soil surface area than
would be expected under site conditions. Also, the contained
system design, where no water is flowing into or out of the
system, is not a realistic simulation of actual site
conditions. Additionally, the method offers no additional
information regarding interstitial fluid movement in a
subsurface system.
Column Test Method - Another experimental measurement method
for determining Kg is the column test method. One version of
this procedure requires a column of contaminated soil of known
concentration taken from the field in an undisturbed manner
(e.g., Shelby tube) which is used as a flow medium for
initially purified water. The soil pore volume for the sample
is calculated and a volume of water equaling the soil pore
volume is forced through the vertically oriented column under
pressure. The effluent is collected and analyzed for the
contaminant of concern. The contaminant concentration
remaining in the soil after the test is completed is then
determined. The result of this analysis and the effluent
concentration can be plugged into the basic Kg equation to
calculate a value.
The column test procedure offers some advantages over the
batch experiment method. Because it is an open flow system and
because the soil is not agitated, it more accurately simulates
the actual site conditions. Additionally, the column test can
be used to obtain other useful information such as the flow
velocity and hydraulic conductivity of the soil and transport
characteristics of the contaminant.
Instead of using purified water in the previously described
procedures, a more appropriate solution would be unsaturated
zone ground water upgradient of the contaminated area at the
site under investigation. This technique would allow a better
simulation of actual site conditions and could potentially
increase the accuracy of the results.
Field Measurements - Experimental field measurements also can
be conducted to determine Kg values. This requires the use
of non-soil-interactive tracers such as tritium, however, this
procedure takes a greater amount of time and cost to conduct
than laboratory experiments such as the batch and column test
methods. Additional information on Kg measurement techniques
using radioactive tracers can be found in the EPA report
520/6-78-007, Volume 1, 1978, entitled: "Radionuclide
Interactions with Soil and Rock Media."
131
-------
EPA Experimental Methodologies - Several experimental
methodology studies relating to the partitioning of compounds
have been and are continuing to be conducted by or through
Robert S. Kerr Environmental Research Laboratory (RSKERL) in
Ada, Oklahoma/ and at other EPA laboratories. One method
utilizes breakthrough curves from column studies to determine a
soil:water Kg,. In this method, breakthrough curves are
developed which plot relative concentration versus soil pore
volumes.
Another method developed for determining K
-------
Solubility and Koc Values For Constituents of Concern
Constituent
Acenapthene
Acenaphthylene
Ace t aldehyde
Acetone
Acetonitrile
Acrolein
Acrylonitrile
Aldicarb
Allyl Alcohol
Aniline
Antimoney (Trisulfide)
Arsenic (Trioxide)
Barium (Hydroxide)
Benzene
Benzo (A) anthracene
Benzo (A) pyrene
Benzo (B)f luoranthene
Benzotrichloride
Benzyl Chloride
Bis(Chloromethyl)Ether
Bis(2)ethylexyl Phthalate
Cadmium (Hydroxide)
Carbon Bisulfide
Carbon Tetrachloride
Chlordane
Chlordide (Sodium)
Chloroacet aldehyde
Chlorobenzene
Chloroform
2-Chlorophenol
Chromium VI (Calcium Chromate)
Chrysene
Copper (Sulfate)
Cyanides (Sodium)
Cyclohexane
Dibenzo(A,H) anthracene
1 , 2-Dichlorobenzene
1,4-Dichlorobenzene
1,2-Dichloroethane
1, 1-Dichloroethene
1,2-Dichloroethene
Dichloromethane
1,2-Dichloropropane
Dichloropropanols (2,3-1-DL)
1, 3-Dichloropropene
Solubilitv1
Value
(ma/1)
3.42E+00
3.93E+00
l.OOE+06
l.OOE+06
l.OOE+06
2.10E+05
7.90E+04
6.00E+03
5.10E+05
3.40E+04
1.20E+00
1.50E+04
9.35E+04
1.78E+03
5.70E-03
3.80E-03
1.40E-02
5.30E+02
3.30E+03
2.20E+04
4.00E-01
2.00E+00
2.30E+03
7.85E+02
1.85E+00
2.20E+05
4.00E+05
4.90E-02
8.20E+03
2.85E+04
4.40E+05
1.80E-03
1.10E+05
3.30E+05
5.50E+01
5.00E-04
l.OOE+02
7. 90E+01
8.70E+03
4.00E+02
7.00E+02
2.00E+04
2.70E+03
1.60E+05
2.90E+03
KOC
Value
(1/mal
4.60E+03
2.50E+03
2.19E+00
2.19E+00
2.19E+00
4.90E-01
8.50E-01
3.65E+01
3.17E+00
1.30E+02
5.00E+04
5.00E+00
5.00E+01
8.30E+01
1.40E+06
5.50E+06
5.50E+05
1.39E+02
5.07E+01
1.20E+00
2.00E+09
5.00E+02
6.18E+01
4.39E+02
1.40E+05
5.00E-02
3.62E+00
3.30E+02
4.40E+01
7.30E+01
5.00E+00
2.00E+05
5.00E+03
5.00E+00
4.82E+02
3.30E+06
1.70E+03
1.70E+03
1.40E+01
6.50E+01
5.90E+01
8.80E+00
5.10E+01
5.99E+00
2.70E+01
133
-------
Solubility and Koc Values For Constituents of Concern
(continued)
Constituent
2,4-Dichlorophenol
2, 6-Dichlorophenol
Dimethoate
Dimethyl Alkylamines
2,4-Dimethylphenol
1, 3-Dinitrobenzene
2,4-Dinitrotoluene
Dinoseb
Endosulfan
Epichlorohydrin
Ethylbenzene
Ethylene Dibromide (EDB)
Ethylene Oxide
Fluoranthene
Fluorides (Sodium)
Formaldehyde
Heptachlor
Hexachlorobenzene
Hexachlorobutadiene
Hexachloroethane
Hexachlorocyclopentadiene
Hexane
Hydroquinone
Indeno ( 123-CD) Pyrene
Lead (Hydroxide)
Lindane
Maleic Anhydride
Mercury (Oxide)
Methanol
Methomyl
Methyl Chloride
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Isocyamate
Methyl Methacrylate
Molybdenum (Trioxide)
Naphthalene
Naphthoquinone
Nickel (Hydroxide)
Nitrate (Sodium)
Nitrobenzene
4-Nitrophenol
Paraldehyde
Parathion
Solubility1
Value
(ma/1}
4.60E+03
4.80E+02
2.50E+04
2.50E+02
5.90E+02
4.70E+02
2.70E+02
5.00E+01
4.00E-01
6 . OOE+04
1.52E+02
4.30E+03
l.OOE+06
2.60E-01
1.90E+04
4.00E+05
1.80E-01
6.00E-03
2.00E+00
5.00E+01
2.00E+00
l.OOE+01
7. OOE+04
5.30E-04
1.25E+02
7.80E+00
1.63E+05
4.80E+01
l.OOE+06
1. OOE+04
6.50E+03
3.53E+05
1.70E+04
6.70E+00
2.00E+01
7.10E+02
3.20E+01
2.00E+02
8.20E+01
6.70E+05
1.90E+03
1.60E+04
1.20E+05
2.40E+01
Koc
Value
(I/ma1*
3.80E+02
1.46E+02
1.66E+01
2.09E+02
9.60E+01
1.48E+02
4.50E+01
5.08E+02
9.60E-03
1.03E+01
1.10E+03
1.40E+01
2.19E+00
3.80E+04
5.00E+00
3.62E+00
1.20E+04
3.90E+03
2.90E+04
2. OOE+04
4.80E+03
1.23E+03
9.44E+00
1.60E+06
5.00E+03
1.10E+03
5.93E+00
5.00E+02
2.19E+00
2.75E+01
4.30E+00
3o88E+00
2.06E+01
1.53E+03
8.40E+02
5.00E+03
9.40E+02
2.37E+02
5.00E+02
5.00E-02
3.60E+01
4.50E+01
7.02E+00
1. OOE+04
134
-------
Solubility and Koc Values For Constituents of Concern
(continued)
Constituent
PCB-1254
Pentachloronitrobenzene
Pentachlorophenol
Phenol
Phorate
Phthalic Anhydride
2-Propanol
Pyridine
TCDD (Dioxin)
1,1/1, 2-Tet rachloroethane
1/1,2, 2-Tetrachloroethane
Tetrachloroethene
Tetraethyl Lead
Thallium (Hydroxide)
Toluene
Toluene Diamine (TDA)
Toluene Diisocyanate (TDI)
Toxaphene
1 , 2 , 4-Trichlorobenzene
1, 1, 1-Trichloroethane
1 / 1 / 2-Tr ichlorodethane
Trichloroethene
2,4, 6-Trichlorophenol
2,4, 6-Trinitrotoluene
Vanadium (Pentoxide)
Vinyl Chloride
Xylenes
Zince (Oxide)
Solubility1
Value
(ma/1}
3.10E-02
7.10E-02
1.40E+01
9.30E+04
5.00E+01
6.20E+03
l.OOE+06
l.OOE+06
2.00E-04
2.00E+02
2.90E+03
2.00E+02
8.00E-01
2.40E+05
5.35E+02
5.00E+05
O.OOE+00
5.00E-01
3.00E+01
4.40E+03
4.50E+03
1.10E+03
8.00E+02
2.00E+02
4.50E+03
2.70E+03
1.60E+02
1.30E+00
Koc
Value
( I/ma)
2.95E+04
1.87E+04
5.30E+05
6.00E+00
3.20E+03
3.58E+01
2.19E+00
2.19E+00
3.30E+06
2.37E+02
1.18E+02
3.64E+02
4.94E+03
5.00E+02
2.50E+02
3.20E+00
1.55E+00
9.64E+02
9.20E+03
1.52E+02
5.60E+01
1.26E+02
2.00E+03
1.60E+03
5.00E+02
8.20E+00
2.68E+02
5.00E+02
Solubilities for inorganics are based on the compound listed
in parentheses and are given in terms of the constituent of
interest (e.g./ solubility of zinc oxide given as mg/1 zinc),
135
-------
-------
APPENDIX E
137
-------
H
W
00
U.S. DA DRIWIWG VATDt StAHDUGS, CRITERIA, AMI GUIDCLIKES TOR PROTECTION OT 113UK HEALTH
All value* prejcnltd la tM» Uble mutt be confined
As of August 1, 1988
fug/1)
This document provides a gumwrr of Information In the Superfuad Public Health Evaluation Kaoual, tbe Integralttd Risk Information System (IRIS) outputs, and other source docuwntx.
Only source Documents should be referenced In the ROD.
Chemical
Acenaphtbene
Acenaphthylene
Acetone
Acroleln
Acrylamlde
Acrylonltrlle
Alachlor
Aldlcarb
Aldrln
Anthracene
Antimony, total
Arsenic, total
Asbestos
Barium, total
Benzene
Benzldlne
Benzo (a) anthracene
Benzo (a)pyrene
Benzo (b) f luoranthene
Bento (k) f luoranthene
Benzo(g,h,i)perylene
Beryllium, total
alpha-BHC
beta-BIIC
gamma-BHC (Llndane)
Bls-2-chloroethyletner
Bls(2-ethylhexyl)
phthalate
Bromodlchloromethane
Bromofon
2-Butanone (MHO
Cadmium, total
Practical
Quanti-
fication
Limits
(a)
10
10
100
5
-
5
-
-
0.05
10
30
10
-
20
2
-
10
10
10
10
10
2
0.05
0.05
0.05
10
10
1
2
10
1
For additional intonation contact your regional coordinator or the Office of Information Resources Management.
Water Quality Criteria for Protection of Human Health (q)
Time Columns Must Be
Verified by IRIS
HCL hCLG
(b) (c)
-
-
-
-*
-
.*
-t
-
-
-
50*
_*
1000*
5 0
-
-
-
-
-
-
-
-
-
4*
-
-
100(1)
100(1)
-
10*
Proposed
MCLGtdl
_
-
-
-
0
-
0
9
-
-
-
50
7.0(K)
1500
-
-
-
. -
-
-
-
-
-
-
0.2
-
-
-
-
-
5
Concentration
at 10
Risk Level
(e,f)
_
-
-
-
-
0.06
-
-
-
-
-
-
-
-
1
0.0002
-
-
-
-
-
-
-
-
-
0.03
50
-
-
-
-
Concentration
at
RID Level
(e,f)
_
-
3500
-
-
-
350
45.5
1.05
-
14
-
-
1750
-
-
'
-
-
-
-
175
-
-
10.5
-
700
700
700
1,750
-
Ingestlon of
Drinking Knter
Only
Threshold
Toxiclty
Protection
20
-
-
540
-
-
-
-
-
-
146
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
21,000
-
-
-
10
_
10
Cancer
Risk
M
-
-
-
-
0.063
-
-
0.0012
-
-
0.025
0.030(10
-
0.67
0.00015
J
J
3
d
3
0.0039
0.013
0.023
0.017
-
-
-
-
-
-
Ingestlon of Drinking Ingestlon of
Kater and Aquatic Aquatic Organisms
Organisms Only
Threshold
Toxiclty
Protection
_
-
-
320
-
0.058
-
-
-
-
146
-
-
1,000
-
-
-
-
-
-
-
-
-
-
-
-
15,000
0.19
-
-
10
10 Threshold
Cancer Toxiclty
Klsk Protection
_
-
-
780
-
-
-
-
0.000074
-
45000
0.0022
0.030 (k)
-
0.66
0.00012
J
)
1
J
j
0.0068
0.0092
0.0163
0.0186
0.03
50,000
15.7
-
-
-
10
Cancer
Risk
.
-
-
-
-
0.65
-
-
0.000079
-
-
0.0175
-
-
40
0.00053
J
i
j
1
J
0.117
0.031
0.0547
0.0625
1.36
-
-
-
-
-
COM
Health
Advisory (h)
Lifetime
70 kg
Adult
.
-
-
-
-
-
-
10
-
-
-
-
-
1500
-
-
-
-
-
-
-
-
-
-
2
-
-
-
-
170
5
-------
Hater Quality Criteria for Protection of Humn Health (g'
CO
VO
Cheiical
Cartofuran
Carbon dlsnlflde
Carbon tetrachloride
Chlorobenzene
Chlordme
Chloroform
2-Chloronaphthalene
2-Chloix>phenol
3-Chloropbenol
4-Chlorophenol
Chralin (total)
ChroBluii (hexavalent)
Chromlua (trivalent)
Chrysene
Copper, total
Cyanide
COD
DDE
DDT
2,4-D
DBCP
Dlbento(a,h) anthrancene
Dlbutylphthalate
1 2-Dlchlorobenwne ( o)
,3-Dlchlorobenieneta)
,4-Dlchlorobentene(p)
, 2-Dlchloroethane
,1-Dlchloroethene
cls-1 ,2-Dlchloroethene
trans-1 ,2-Dldiloroetbene
Dichlorow thane
1,2-Dlchloropropane
Dlchloropropene
Dleldrln
Dlethyl phthalate
DlMthyl phtbalate
3-3'-Dlcblorobentldine
2,3-Dlchlonphenol
2 ,4-Dlchlorophenol
Practical
Quanti-
fication
Units
(a)
5
1
2
0.1
0.5
10
5
-
-
10
-
-
10
60
40
0.1
0.05
0.1
10
5
10
2
2
S
2
O.S
1
-
1
5
O.S
S
O.S
S
5
20
-
S
These Colinms Must Be
Verified br IRIS
NCI
(b)
_*
-
S*
-
_*
100(1)
.
-
-
-
50*
-
-
--
1,000*
-
-
.
-
100*
-
-
-
_*
-
75
5
7
.*
_*
-
_*
-
-
-
-
-
-
-
HO.G
(c)
-
0
-
-
-
-
-
-
-
-
-
-
-
-
-
-
.
-
-
-
-
-
-
-
7S
0
7
-
-
-
-
-
-
-
-
-
-
Proposed
MOGIdl
36
-
.
60
0
-
-
-
-
-
120
-
-
-
1300
-
-
.
_
70
0
-
-
-
-
-
-
70
70
-
6
-
-
-
-
.
.
-
Concentration
at 10
Bisk Level
(e.f)
_
-
0.3
-
0.027
-
-
-
-
-
-
-
-
-
-
-
-
-
.
0.01
-
-
-
-
-
-
0.4
0.06
-
-
5
-
- -
-
-
-
-
-
-
Concentration
at
RfD Level
(e.f)
175
3,500
24.5
-
1.75
350
-
-
-
-
-
175
35,000
-
-
700
-
.
17.5
350
-
. -
3,500
-
-
-
.
315
.
.
2,100
.
10.5
.
28,000
.
.
.
105
Ingest Ion of
Drinking Hater
Onlr
Threshold
Toxlclty
Protection
_
-
-
488
-
-
-
-
-
-
-
50
179,000
-
1,000
200
.
.
_
-
.
"
44,000
470
470
470
.
.
.
.
.
.
87
.
.
350,000
.
_
3,090
£
10^
Cancer
Risk
-
0.42
-
0.022
0.19
'
-
-
-
-
-
-
J
-
-
-
.
0.0012
-
-
J
-
-
-
-
.
0.033
-
-
0.19
.
.
0.0011
.
.
.
_
.
Ingest ion of Drinking
Hater and Aquatic
OraanlsM
Threshold
Toxlcltr
Protection
_
-
-
488
.
-
-
'-
-
-
-
50
170,000
-
-
203
-
.
.
-
.
-
34,000
400
400
400
.
.
'.
-
.
_
87
.
350,000
313,000
.
_
3,090
.£
10^
Cancer
Risk
.
-
4
-
0.00016
0.19
-
-
-
-
-
-
-
j
-
-
-
.
0.000024
100
.
j
-
-
-
.
0.94
0.033
.
.
0.19
.
.
0.000071
' .
.
0.01
_
.
Ingest Ion of
Aquatic Organises
Only
Threshold
Toxlclty
Protection
_
-
-
-
-
-
' -
-
-
-
-
-
3,433,000
-
-
-
.
.
.
.
.
-
154,000
2,600
2,600
2,600
.
.
.
-
.
.
14,000
.
1,800,000
2,900,000
.
,
3,090
.£
10
Cancer
Risk
_
-
6.94
-
0.00048
15.7
-
-'
-
-
-
-
-
J
-
-
-
.
0.000024
-
.
J
'-
-
.
243
1.85
.
.
15.7
"
.
0.000076
-
.
0.0*2
.
oat
Health
Advisory (h)
Lifetime
70 kg
Adult
36
-
-
300
-
-
--
-
-
-
120
-
-
-'
-
154
-
.
.
70
.
-
-
620
620
75
.
7
70
70
.
.
.
.
.
.
.
.
.
-------
«al»r Quality Criteria far fraUcUen of ttoMn H«*lthla)
Practical
fluantl-
flcatlon
Milts
Chemical (a)
Ha HCLG
(b> le)
Ttwio Colunis Hail Be
Verified by IRIS
Concentration Concentration
»t 10 u
Proposed Mik Level RfD Level
HCI/Hd) (e,f) (e,f)
Inflection of
Drinking Water
Only
Tlirejbold 10"*
Toxlclty Cancer
Protection Risk
Inflation of Drinking
Utter and Aquatic
Orqanlm
Threshold lo"6
Toxlclty Cancer
Protection Rl«k
Ingeatlon of
Aquatic Organisms
Only
Threshold 10~*
Toxlclty Cancer
Protection Risk
COM
Health
Advisory (b)
LlfetlM
70 kg
Adult
Cheilcal
2 , 5-Dlchlorophcnol
2,6-Dlcbloroj>henol
3,4-Dlchlorophenol
2,4-DlKthylplienol
2,4-Dlnltrotoluene
Dloxane
1 , 2-Dlphenylhydraz Inc
Endosulfan
Endosulfan sulfate "
Endrln
Epicblorobydrln
Ethylbenrene
Ethylenedibroiide
Ethyleneglycol
Fluoranthene
Fluorene
Haloie thanes
HepUcblor
Heptachlor epoxlde
Hexachlorobeniene
Hexachlorobutadlene
Hexachlorocyclopentadlene
Hexachloroe thane
Hexane
Indeno ( 1 , 2 , 3-cd) pyrene
Iron, total
Isopborone
Lead, total
Hangenese, total
Mercury (alkyl)
Mercury (inorganic)
Hethoxycblor
2-Metliyl-4-chlorophcnol
3-Hethyl-4-chlorophenol
3-Bethyl-6-cblorophenol
4-Methyl-2-pentanone (HIBK)
4-Hcthylphenol
Nickel, total
Nitric oxide
Nitrobenzene
Practical
gutntl-
flcatlon
Milts
(a)
10
-
5
0.2
150
-
0.1
0.5
0.1
-
2
5
-
10
10
-
0.05
1
0.5
5
5
0.5
-
10
-
10
10
-
2
-
2
-
-
-
5
10
50
.
10
Ha
Ib)
-
-
-
-
-
-
-
-
0.2
_*
.«
_*
-
-
-
0.10
_*
.*
-
-
-
-
-
-
300
-
50
50
-
2*
100*
-
-
-
-
-
-
-
-
HCLG
te)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-'
-
-
-
-
-
-
-
-
-
-
-
-
-
0.05
0
680
0
20
3
340
-
.
1.75
.
70
3,500
-
_
13B
1
-
2,400
0.11
0.046
-
.
-
-
-
.
74
1
-
1,400
0.11
0.042
-
.
-
-
70,000
0
0
-
-
-
0.008
0.004
0.5
-
3
17.5
0.455
70
245
35
1,750
700
3,500
17.5
168
42
5,200
50
10
15.4
19,800
5,200
50
50
0.144
100
13.4
19,800
9.1
0.56
159
3,280
54
0.32
680
7000
0.19
0.011
-
0.021
0.45
-
-
-
-
-
-
-
206
1.9
0.19
0.00028
0.00028
0.00072
0.45
-
-
14,800
520,000
100
0.146
15.7
0.00029
0.00029
0.00074
50
8.74
100
1.1
340
150
-------
Criteria for Protection of Hunan Health(q)
H
ife
H
Practical
Quanti-
fication
Limits MCL HCLG
Chemical (a) (b) (c)_
n-Hltrosodimethylamlne 10 -
n-Nltrosodiethylamlne 10 -
n-Hltrosodi-n-butylamine 10 -
n-Nltrosopyrrolldlne 10 -
n-Nitrosodlphenylamlne 10 - -
Oxamic acid
PCB'» 50 -*
PAHs - -
Pentachlorobenzene 10 -
Pentachlorophenol 5 -*
Phenanthrene 10 - -
Phenol 1 -
Pyrene 10 -
Selenium, total 20 10*
Silver, total 70 50*
Styrene 1 -
2,3,7,8-TCDD 0.005
Tetrachloroethene 0.5 -*
1,1 ,2, 2-Tetrachloroethane 0.5
2,3,4,6-Tetrachlorophenol 10 - -
Thalllun, total 10 - -
Toluene 2 -*
Toxaphene 2 5* -
2,4,5-TP 2 -*
1,2,4-Trlchlorobeniene 10 - -
1,1, 1-Trichloroethane 5 200 200
1,1,2-Trlchloroethane 0.2
Trlchloroethene 1 50
2,4,5-Trlchlorophenol 10 - -
2,4,6-Trlchlorophenol 5 -
Vanadium 40 - -
Vinyl chloride 2 20
Xylene 5 -*
Zinc, total 20 5,000
These Columns
Husl Be
Verified by IRIS
Ingestlon of
Drinking Hater
Only
Ingestlon of Drinking
Hater and
Aquatic
Organisms
Concentration Concentration __.
Proposed
HCLG(d)
-
-
-
-
-
0
-
.
220
-
-
-
45
-
140
-
0
-
-
-
2,000
0
-
-
-
.-
-
-
-
-
440
-
a. Sources 52 FR 25947. Practical quantification limits presented
quantification limits in some cases.
b. 40 CFR 141 and 143.
C. 40 CFR 141.50.
d. 50 FR 46936; November 13, 1965.
e. Integrated Risk Information System database.
£. Assuming drinking water ingestlon of 2 liter/day and
g. 45 FR 79318-79379; November 28, 1980.
h. U.S. EPA, Health Advisories, Harch 1987.
body weight
at 10
Risk Level
(e,f)
-
0.006
0.02
7
-
.
-
-
-
-
-
-
-
-
-
-
0.175
-
-
-
-
-
-
-
0.6
3
-
1.75
-
0.015
-
-
are for standard
of 70 kg.
at
RfD Level
(e,f)
.
-
-
-
-
-
-
.
28
1,050
-
1,400
-
-
105
7,000
-
350
-
1,050
.
10,500
-
-
700
3,150
7,000
-
3,500
-
315(1)
.
350
7,350
Threshold 10
Toxiclty Cancer
Protection Risk
0.0014
0.0008
0.0064
0.016
7.0
. \.
0;013
0.0031
-
1,010
.
3,500
-
10
50
-
1.8e-7
0.88
0.17
-
17.8
15,000
0.026
-
-
19,000
0.60
2.8
-
1.8
.
2
-
5,000
Threshold
Toxiclty
Protection
.
-
-
-
-
-
-
-
74
1,010
-
3,500
-
10
50
-
-
-
-
-
13
14,300
.
-
-
18,400
-
-
2,600
-
.
-
-
-
_£
10 *
Cancer
Risk
0.0014
0.0008
0.0064 '
0.016
4.9
"
0.000079
0.0028
-
-
-
-
-
-
-
-
1.3e-8
0.80
0.17
1
-
-
0.00071
10
-
-
0.6
2.7
-
1.2
-
2.0
-
-
Ingestion of
Aquatic Organisms
Only
Threshold
Toxlcity
Protection
.
-
-
-
-
-
-6
10
Cancer
Risk
16
1.2
0.587
91.9
16.1
ODH
Health
Advisory (h)
Lifetime
70 kg
Adult
.
-
-
*
"
0.000079
-
85
-
-
-
-
-
-
-
-
-
-
-
48
424,000
-
-
-
1,030,000
-
-
-
-
-
-
-
-
0.031
-
-
-
-
-
-
-
-
1.4e-8
8.85
10.7
-
-
-
0.00073
-
-
-
41.8
80.7
-
3.6
-
525
-
-
-
-
220
-
-
-
-
-
140
-
10
-
-
-
2,420
-
52
-
200
-
-
-
-
-
-
400
-
analytical methods. It may be appropriate to use different analytical methods to achieve lower
1. Based on the standard for total trihalonethanes of 100 ug/1.
j. Based on criteria for polycycllc aromatic hydrocarbons (PAlls).
k. Million fibers/liter.
1. For vanadium pentoxide.
* MCL will be proposed In the Federal Register In 1988
. HCLs will
also be proposed
for aldlcarb
sulfoxlde, aldicarb sulfone, atrazlne.
and dibromochloropropane.
-------
-------
APPENDIX F
143
-------
APPENDIX F
Site Name; Matthews Electroplating, VA
Site Description; The 1.7-acre site is located in Roanoke
County, Virginia, approximately two miles west of Salem.
Between 1972 and 1976, two buildings on the site housed an
automobile bumper electroplating operation. Ground water
sampling in 1975 confirmed that a plant well and a nearby
church well were heavily contaminated with hexavalent
chromium. Shortly thereafter the owners of the site declared
bankruptcy. In 1982 an offsite ground water investigation
revealed that 10 local residental wells also had been affected
by chromium contamination. Two areas onsite were identified as
having moderate soil contamination but it was concluded that
the chromium in these areas were adsorbed to the soil. To
control further runoff or leaching contamination, the hew
owners performed some surface cleanup and a clay cover was
placed over a small area of the site where chromium wastes had
been discharged.
Waste Description; The concentrations of total chromium found
onsite were as high as 11,500 ug/1 in ground water and 2,998
mg/kg in soils.
Target Cleanup Level Methodology; The RI/FS was completed in
1983, after which a waterline from the nearby municipal water
distribution system was extended to approximately 30 nearby
homes. The results of the RI indicated that most of the
chromium leaching from the soil had reached the ground water
prior to the placement of the clay cap in 1977. The highest
chromium concentrations in residental wells were encountered at
the beginning of the ground water and soil sampling in
1975-1976 and had decreased significantly since that time. The
maximum concentration of chromium in groundwater had decreased
from 11,500 ug/1 in 1976 to .192 ug/1 in 1981. Since the
levels of chromium were expected to decrease further over time
as a result of ground water movement and dilution, a ground
water remedy was deferred at that time. To determine if
further remedial actions were necessary a full assessment of
the extent of the contaminant plume was conducted.
EPA conducted post-remediation sampling in 1987 for both ground
water and soil. The results of the sampling showed chromium
levels had decreased to a point that no longer posed a threat
to public health or the environment. As a final measure,
several open drums were removed and two tanks were excavated
from the site. Based on the sampling results and prior
response activities no further action was recommended. The
State of Virginia has agreed to conduct post deletion
monitoring of the existing residential wells for a period of
three years.
* U.S.GOVERNMENT PRINTING OFF ICEl 1 989-748-1S9-00366
144
------- |