&EPA
              United States
              Environmental Protection
              Agency
Office of Water
Regulations and Standards
Washington, DC  20460
              Water
              TECHNICAL SUPPORT
              DOCUMENT
              Landfilling of Sewage Sludge

-------
                                  PREFACE


    Section 405(d) of the Clean Water Act requires the U.S.  Environmental
Protection Agency (EPA) to develop and issue  regulations that identify:

    •  Uses for sludge, including various means of disposal
    •  Factors, including costs, which must be considered when determining the
       measures and practices applicable to each use or disposal method
    •  Pollutant concentrations that interfere with each use or disposal
       method

    To comply with this statutory mandate, EPA has embarked  on a program to
develop five major technical regulations for  the following areas:  land
application/distribution and marketing; monofilling; surface disposal;
incineration; and reduction of pathogens and  vector attraction.  EPA also has
proposed regulations governing the establishment of State sludge management
programs, which will implement both existing  and future criteria (40 CFR 501).

  \	The primary goal of the proposed monofill regulation is  to protect human
health and the environment.  Included in this proposed regulation are
provisions to protect air and groundwater quality from the deleterious effects
that potentially may occur due to sludge monofilling.   This  document provides
the technical background and justification for the provisions contained in
Subpart D of the proposed regulation.  [

    Public comment on the technical adequacy  and scientific  validity of this
document as well as on the requirements contained in the proposed regulation
should be submitted during the public comment period.   Any questions related
to this document may be directed to:

            Norma K.  Whetzel
            U.S.  Environmental Protection Agency
            Wastewater Solids Criteria Branch
            Washington, DC 20460
            202-475-7313
                                    Martha Prothro, Acting Director
                                    Office of Water Regulations and Standards
                                    -i-

-------
                            TABLE OF CONTENTS
                                                                        Page

LIST OF TABLES                                                          vii

LIST OF FIGURES                                                          ix

LIST OF UNITS AND ACRONYMS                                               xi


L.  TECHNOLOGY AND PROCESSES                                            1-1

      1.1  Monofills                                                    1-2
      1.2  Leachate                                                     1-4
      1.3  Surface Water Contaminant                                    1-4
      1.4  Gas Control                                                  1-6
      1.5  Land Requirements                                            1-6
      1.6  Storage                                                      1 7
      1.7  Good Practices                                               1-8
      1.8  Sludge Quality                                               1-8


2.  RISK ASSESSMENT METHODOLOGY                                         2-1

      2.1  Introduction                                                 2-1
      2.2  Identification of Pathways of Exposure and Health and        2-1
            Environmental Criteria
           2.2.1 Pathways of Exposure                                   2-2
           2.2.2 Human Health and Environmental Impact Criteria         2-6
      2.3  Overview of SLUDGEMAN                                        2-7
      2.4  Description of the Groundwater Components  of the             2-10
            SLUDGEMAN Model
           2.4.1 Pulse-time Calculation (SATM1 and SLUGMAN)             2-10
           2.4.2 TJnsaturated Zone Model (CHAIN)                         2-12
           2.4.3 Saturated Zone Model (AT123D)                          2-18
           2.4.4 Integrating the Unsaturated and Saturated Zone         2-19
                 Models
      2.5  Description of the Vapor Pathway Components of the           2-20
            SLUDGEMAN Model
      2.6  Use of SLUDGEMAN to Establish Criteria for Pollutants        2-22
            in Sludges
           2.6.1 Groundwater Pathway Calculation                        2-22
           2.6.2 Vapor Pathway Calculation                              2-25
      2.7  Science Advisory Board Review                                2-25
                                     -111-

-------
                            TABLE OF CONTENTS (Continued)

                                                                        Page

3.   DATABASE FOR THE RISK MODEL                                         3-1

      3.1  Model Sludge Parameters                                       3-1
           3.1.1 Sludge Moisture Content                                 3-1
           3.1.2 Sludge Storage Capacity                                 3-3
           3.1.3 Sludge Density                                         3-3
           3.1.4 Specific Gravity                                       3-5
      3.2  General Hydrologic Parameters                                 3-7
           3.2.1 Net Recharge                                           3-7
           3.2.2 Depth to Ground Water                                  3-8
           3.2.3 Aquifer Thickness                                       3-9
           3.2.4 Groundwater pH                                         3-9
           3.2.5 Groundwater Eh                                         3-10
      3.3  Unsaturated Zone Parameters                                  3-10
           3.3.1 Unsaturated Zone Soil Type                             3-10
           3.3.2 Unsaturated Zone Thickness                             3-11
           3.3.3 Slope of the Soil  Moisture Retention Curve              3-12
           3.3.4 Effective Porosity of the Unsaturated Zone              3-12
           3.3.5 Bulk Density in the Unsaturated Zone                   3-14
           3.3.6 Saturated Soil Hydraulic Conductivity                  3-15
      3.4  Saturated Zone Parameters                                    3-15
           3.4.1 Saturated Zone Soil Type                               3-16
           3.4.2 Effective Porosity in the Saturated Zone                3-16
           3.4.3 Hydraulic Gradient in the Saturated Zone                3-18
           3.4.4 Bulk Density in the Saturated Zone                      3-18
           3.4.5 Saturated Zone Hydraulic Conductivity                  3-18
      3.5  Surface Parameters                                           3-20
           3.5.1 Landfill Site Geometry                                 3-20
           3.5.2 Distance to the Property Boundary                       3-20
           3.5.3 Surface Wind Velocity                                  3-22
           3.5.4 Air Temperature                                        3-22
           3.5.5 Air-filled Porosity of Cover Soil                       3-22
           3.5.6 Total Porosity of Cover  Soil                           3-22
           3.5.7 Cover Thickness                                        3-23
      3.6  Chemical-specific Parameters                                 3-23
           3.6.1 Concentrations of Contaminants in  Sludge                3-23
           3.6.2 Concentrations of Contaminants in  Sludge                3-23
                 Leachate
           3.6.3 Distribution Coefficient                               3-26
           3.6.4 Saturated and Unsaturated Zone Decay Rate              3-28
           3.6.5 Background Concentrations of Contaminants              3-28
           3.6.6 Health Effects Levels                                  3-31
           3.6.7 Molecular Weight                                       3-34
           3.6.8 Henry's Law Constants                                  3-34
                                     -iv-

-------
                            TABLE OF CONTENTS (Continued)

                                                                        Page

4.   SENSITIVITY ANALYSIS                                                4-1

      4.1  Effect of Soil Depth and Carbon Content                       4-2
           4.1.1 Results for Class 1 Aquifers                           4-4
           4.1.2 Results for Class 2 Aquifers                           4-6
      4.2  Effect of Recharge Rate                                      4-8
      4.3  Effect of Groundwater Velocity                               4-9
      4.4  Effect of Aquifer Thickness                                  4-11
      4.5  Effect of Eh and pH                                          4-12
      4.6  Effect of Sludge Moisture Content                            4-13


5.   POLLUTANT LIMITS                                                    5-1
6.  GENERAL SITING REQUIREMENTS                                         6-1

      6.1  Airport Siting Requirements                                  6-1
           6.1.1 Impacts of Siting Facilities near Airports              6-1
           6.1.2 Regulatory Requirement for Siting Monofills             6-4
                 near Airports
      6.2  Floodplain Siting Requirements                               6-5
           6.2.1 Types of Floods Occurring in 100-yr Floodplains         6-5
           6.2.2 The History of the 100-yr Floodplain as  an  EPA         6-7
                 Regulatory Standard
           6.2.3 Impacts of Siting Facilities in Floodplains             6-9
           6.2.4 Preventive Measures and Emergency Responses  to         6-12
                 Flooding of Facilities
           6.2.5 Case Studies                                           6-14
           6.2.6 Regulatory Requirement for Siting Monofills  in         6-14
                 Floodplains
      6.3  Wetlands Siting Requirements                                 6-17
           6.3.1 Impacts of Siting Facilities in Wetlands               6-19
           6.3.2 Current Federal Protection Measures                    6-20
           6.3.3 Regulatory Requirement for Siting Monofills  in         6-21
                 Wetlands
      6.4  Fault Area Siting Requirements                               6-22
           6.4.1 Impacts of Siting Facilities in Fault Areas             6-24
           6.4.2 Regulatory Requirement for Siting Monofills  in         6-25
                 Fault Areas
      6.5  Seismic Impact Zone                                          6-25
           6.5.1 Impacts of Siting Facilities in Seismic                 6-26
                 Impact Areas
           6.5.2 Regulatory Requirement for Siting Monofills             6-28
                 in Seismic Impact Areas
           6.5.3 Methods for Determining Seismic Risk                   6-29
                                   -v—

-------
                            TABLE OF CONTENTS (Continued)

                                                                        Page

                                                                        r  o A
      6.6  Siting Requirements  for Unstable Areas
           6.6.1 Types  of Unstable Areas
           6.6.2 Impacts  of Siting Facilities  in Unstable Areas          b-J/
           6.6.3 Alternatives
           6.6.4 Regulatory Requirement for Siting Monofills in          6-jjy
                 Unstable Areas


7.   MANAGEMENT PRACTICES                                                 7~1

      7.1  Landfill Cover Requirements                                  I-\.
           7.1.1 Landfill Cover                                         ~>'-l
           7.1.2 Depth  of Cover                                         7"2
           7.1.3 Characteristics  of  Cover Material                       7-2
      7.2  Disease Vector Control Requirements                           7-3
      7.3  Requirements for Control  of Explosive Gases                   7-4
      7.4  Access Control Requirements                                  7-6
      7.5  Runon/Runoff Control Requirements                             7-7
           7.5.1 Runon                                                   7-8
           7.5.2 Runoff                                                 7-8
8. REFERENCES                                                           8-1


APPENDIX A       PARTITIONING OF POLLUTANTS  BETWEEN SLUDGE SOLIDS
                 AND WATER

APPENDIX B       SENSITIVITY ANALYSIS  ON  SELECTED MODEL PARAMETERS

APPENDIX C       APPROVED METHODS FOR  SITE-SPECIFIC PARAMETERS
                                    -VI-

-------
                               LIST OF TABLES



Table No.   Title                                                         Page

Table 1-1  Range of Constituent Concentrations in Leachate from Sludge  1-5
           Monofills

Table 3-1  Summary of Model Parameters and Assigned Values              3-2

Table 3-2  Typical Sludge Solids Content by Landfill Type               3-4

Table 3-3  Typical Values for  the Slope of the Soil Moisture Retention  3-13
           Curve by Soil Type

Table 3-4  Effective Porosities for General Hydrogeologic               3-17
           Classifications

Table 3-5  Landfill Site Geometry                                       3-21

Table 3-6  Concentrations of Contaminants in Sludge                     3-24

Table 3-7  Concentrations of Contaminants in Sludge Leachate            3-25

Table 3-8  Distribution Coefficients                                    3-27

Table 3-9  Saturated and Unsaturated Zone Decay Rates                   3-29

Table 3-10 Background Concentrations of Contaminants                    3-30

Table 3-11 Health Effects Levels                                        3-32

Table 3-12 Standard Molecular  Weights  for Modeled Pollutants            3-35

Table 3-13 Henry's Law Constants for Selected Contaminants              3-36

Table 4-1  Input Parameters for the Baseline Case                       4-3

Table 4-2  Effect of Soil Depth and Organic Carbon Content on Maximum   4-5
           Allowable Pollutant Concentrations for Class I Aquifers

Table 4-3  Effect of Soil Depth and Organic Carbon Content on Maximum   4-7
           Allowable Pollutant Concentrations for Class II Aquifers
                                    -Vll-

-------
                         LIST OF TABLES (Continued)
Table No.   Title                                                         Page

Table 4-4  Effect of Groundwater Velocity on Maximum Allowable  Sludge   4-10
           Concentrations

Table 5-1  Maximum Sewage Sludge Concentration                          5-3

Table 6-1  Distribution of Bird Strikes  by Aircraft  Part  Struck for      6-3
           U.S. Military Aviation
                                 -viii-

-------
                              LIST OF FIGURES




Figure No.  Title                                                         Page

Figure 2-1 Routes to Human Exposure from Landfilling Sludge             2-3

Figure 2-2 Contaminant Migration Pathways for Narrow Trench             2-4
           Landfills

Figure 2-3 Contaminant Migration Pathways for Pit or Wide               2-5
           Trench Landfills

Figure 5-1 Sewage Sludge Monofill                                       5-5

Figure 6-1 Existing Flooding Problems in the United States              6-6
                               -IX—

-------
                       LIST OF UNITS AND ACRONYMS
ac          acre
BEHP        bis(2-ethylhexyl)phthalate
bw          body weight

CFR         Code of Federal Regulations
CWA         Clean Water Act

ODD         Bis l,l-(4-chlorophenyl)-2,2-dichloroethane
DDE         Bis l,l-(4-chlorophenyl)-2,2-dichloroethylene
DDT         Bis 1,1-(4-chlorophenyl)-2,2,2-trichloroethylene

Eh          oxidation-reduction potential
EO          Executive Order
EPA         U.S. Environmental Protection Agency

FAA         Federal Aviation Administration
FR          Federal Register
ft          feet

ha          hectare
HEL         health effects level
hr          hour

kg          kilogram
kd          distribution coefficient
KO,.          organic carbon partition coefficient
K^          octanol-water partition coefficient
K^          saturated hydraulic conductivity

L           liter
L<.          leachate concentration
Ly          limiting leachate concentration
LEL         lower explosive level
In          natural logarithm

m           meter
m2          square meter
m3          cubic meter
MCL         maximum contaminant level
MEI         most exposed individual
MF          modifying factor
mg          milligram
mL          milliliter
mm          millimeter
mph         miles per hour
MPN         most probable number
mt          metric ton
mv          millivolt
                                     -XI-

-------
                 LIST OF UNITS AND ACRONYMS (Continued)
NOAEL       no-observed-adverse-effects level

OHEA        Office of Health and Environmental Assessment
ORD         Office of Research and Development
OWRS        Office of Water Regulations and Standards

PCB         polychlorinated biphenyl
pH          relative hydrogen ion concentration

RCRA        Resource Conservation and Recovery Act
RfD         Risk Reference Dose

SAB         Science Advisory Board
Sc          sludge concentration
Sd          limiting sludge concentration
su          standard units

t^          environmental half-life
tc          contaminant travel time
TCE         trichloroethylene
TKN         total Kjeldahl nitrogen
TOT         time of travel
TW          water travel time

ug          microgram
UF          uncertainty factor

WRC         Water Resources Council

yr          year
                                      -xix—

-------
                                SECTION ONE

                       TECHNOLOGY AND PROCESSES


    This section provides an overview of landfill technology and practices.
It describes good management practices,  but does  not refer to specific
regulatory requirements.

    Landfilling is a sludge disposal method in which sludge is deposited in a
dedicated area, alone or with solid waste,  and buried beneath a soil cover
Landfilling is primarily a disposal method, with  no attempt to recover
nutrients and only occasional attempts to  recover energy from the sludge.
Currently, about 41% of the municipal wastewater  sludge  generated in the
United States is landfilled.

    To a certain extent landfilling, like  land application, is an extension of
sludge treatment.  However, there is an important difference.  When sludge is
landfilled, insufficient oxygen is available to support  aerobic degradation,
such as occurs during land application and composting.   Instead,  anaerobic
degradation occurs.  Anaerobic conditions  degrade the sludge more slowly and
less completely than aerobic processes.   In addition, anaerobic degradation
produces methane gas that must be properly vented or collected from the
landfill.

    Two major types of landfilling are currently  practiced:  sludge-only
disposal (monofill),  in which sludge is buried, usually  in trenches, and co-
disposal, in which sludge is disposed with other  solid waste at a municipal
solid waste landfill.  Approximately 1.3%  of the  sewage  sludge generated in
the United States is disposed in monofills.  Because the proposed regulation
covers sludge monofills only, the following sections relate primarily to
monofilling technology and processes.
                                     1-1

-------
1.1  MONOFILLS

    Most sludge-only landfills consist of a series of trenches dug into the
ground into which dewatered sludge is deposited and then covered with soil.
Other sludge-only landfill designs exist (area-fill mounds, area-fill layers,
and diked containment) in which the sludge is deposited on the ground surface,
but these designs are not commonly used.   Sludge landfill trenches range from
1-15 meters (m) [3-50 feet (ft)]  in width.   When narrow trenches are used
[1-3 m (3-10 ft) wide],  dewatered sludge is usually deposited in the trench
from a haul vehicle alongside the ditch.  The sludge must be less than 30%
solids and the trench floor must be nearly level to ensure that the sludge
will spread evenly throughout the narrow trench.  A wide trench [3-15 m (10-
50 ft) wide] allows the haul vehicle to work within the trench itself.  In
this case, the sludge should be at least 30% solids (which may include bulking
material, such as fine sand) to ensure that it will stay in piles and not
slump.  The addition of a bulking agent is generally not cost-effective if the
sludge solids content is less than about 20%.  If the sludge solids content is
too low, the sludge should be further dewatered at the treatment plant.

    The sludge is usually covered with soil the same day it is deposited to
minimize odors and to prevent insects, birds, and other vectors from
contacting the sludge and spreading contaminants.   As each new trench is dug,
the excavated soil is used to cover the sludge in a nearby trench.   If the
sludge is- solid enough to support a vehicle (greater than about 30% solids),
soil cover can be applied by a track dozer within the trench.   For sludges
less than 30% solids, cover must be applied by a front-end loader or dragline
next to the ditch.

    Generally, sludges must contain at least 20% solids in order to support
cover material.  Narrow trenches can handle sludges as low as  15% solids
because the ground on either side helps support the cover,  but narrow trenches
are relatively land intensive.  Sludge applications range from about
460-2,120 dry metric tons per hectare (dry mt/ha)  [200-940 tons per
acre (tons/ac)], including areas between trenches.   Wide trench operations are

                                      1-2

-------
less land-intensive than those using narrow trenches, with sludge applications
ranging from about 1,200 to 5,430 dry mt/ha (530-2,440 tons/ac).

    At area fills, sludge is placed on the original ground surface.
Excavation is not required because sludge is not placed below the surface,
thus area-fill application is often used in areas with shallow bedrock or
ground water.  There are three methods of area-fill application:  area-fill
mounds, area-fill layers, and diked containment.

    In area-fill mound applications, the sludge solids content should be no
more than 20%.  Sludge is mixed with a soil-bulking agent to produce a mixture
that is physically more stable and has greater bearing capacity   The sludge
is usually mixed at one location and then hauled to the filling area.  At the
filling area, the mixture is stacked into mounds approximately 6 ft high, and
3 ft of cover material is applied.

    In area-fill layer applications, sludge is received at the site and mixed
with a soil-bulking agent.  The mixture is spread evenly in layers from 0.5-
3 ft thick in a number of applications.  Interim soil cover is applied between
consecutive layers in 0.5-1-ft thick applications.  Final soil cover is from
2-4 ft thick.

    In diked containment applications, sludge is placed entirely above the
original ground surface.  Dikes are constructed on level ground around all
four sides of a containment area.  Access is provided to the top of the dikes
so that haul vehicles can dump sludge directly into the containment.  Usually,
diked containment operations are conducted without adding soil bulking agents.
Diked containments are relatively large, with typical dimensions of 10-500 ft
wide, 100-200 ft long, and 1-30 ft deep.
                                     1-3

-------
1.2  LEACHATE

    Leachate is generated from the  excess moisture in the sludge, usually  with
some contribution from rainfall.  The  type and amount of constituents  in
leachate from a sludge monofill depend on the nature of the sludge.  Table 1  1
gives the range of constituent concentrations in leachate from several  study
sites.

    If monofill leachate reaches an aquifer, heavy metals and toxic  organic
chemicals are of particular concern because  of their possible adverse health
effects.  If leachate enters surface waters, the resulting elevated  nutrient
levels can cause eutrophication and concomitant undesirable algal blooms and
fish kills.  Pathogen contamination of drinking water supplies also  could  have
adverse health effects.

    The potential for groundwater contamination can be reduced by properly
covering monofills and by installing liners  to contain any leachate  within the
fill area.  Leachate is then treated to attenuate harmful contamination.   Most
States (72%) require or can require that soil-based liners, synthetic  liners,
or both be installed in a sludge monofill.

    A leachate collection system should be installed in any monofill where
leachate is being contained and where  water  tends to pond in the fill  area.
The two types of collection systems are:   (1) A sump into which  leachate
collects and is subsequently pumped to a holding tank or pond, and  (2)  a
series of drain pipes or tiles that intercept and channel the leachate  to  the
surface or to a sump.
1.3 SURFACE WATER CONTAINMENT

    Based on good management practices,  all  upland drainage  should be directed
away from the monofill.   Working areas  of the  monofill  should have a grade
greater than 2% to promote runoff and prevent  ponding,  but less than 5% to
                                      1-4

-------
  TABLE 1-1.  Range of Constituent Concentrations in Leachate from
               Sludge Monofills
 Constituent                               Concentration3
 Chloride                                       20-600
 S04                                            1-430
 Total  organic  carbon                          100-15,000
 Chemical  oxygen  demand                        100-24,000
 Calcium                                        10-2,100
 Cadmium                                     0.001-0.2
 Chromium                                     0.01-50b
 Zinc                                         0.01  36
 Mercury                                    0.0002-0.0011
 Copper                                      0.02-37
 Iron                                           10-350
 Lead                                          0.1  10b
 TKNC                                       100-3,600
 Fecal  coliform                             2,400-24,000
                                          MPN/100 mLd
 Fecal  streptococcus                         2,100-240,000
                                          MPN/100  mLd
aConcentration is in milligrams per liter unless otherwise noted.

bThe maximum concentrations shown exceed the limits specified in
 40 CFR 261.24 Table I.  These limits define hazardous wastes under
 RCRA.

cTotal Kjeldahl nitrogen.

dMPN/100 mL = most probable number/100 milliliters (mL).

Source:  EPA, 1984.
                               1-5

-------
reduce flow velocities and minimize erosion.   Straw bales,  berms,  or
vegetation can be used to reduce flow velocities.   Siltation ponds will
probably be necessary to settle the solids contained in the site runoff.
1.4 GAS CONTROL

    The decomposition of organic matter in sludge and solid waste produces
methane and other gases, including trace amounts of hydrogen sulfide.   Methane
is  the gas of primary concern.  It can seep by diffusion through sludge and
other materials into nearby buildings or underground structures,  such as
utility tunnels, where it may accumulate to explosive concentrations (5-15%)
To  prevent this hazard, systems to collect gases usually are installed in
monofills located near buildings or underground structures.   Collected gas can
be  vented to the atmosphere or incinerated.   Recovering the methane as an
energy source is usually not economical at monofills.
1.5  LAND REQUIREMENTS

    Monofilling can require substantial amounts of land.   For example,  a
municipality generating 25 dry mt (28 dry tons) of sludge per day (i.e.,
population of about 230,000)  will require approximately 2-20 ha (4-50 ac) of
land per year for monofilling,  depending on trench width, fill-area depth, and
sludge solids content.   This  range is important because the areas suitable for
landfilling are limited by land-use concerns in the community.  Finding and
gaining access to an adequate landfill site is  often the  most significant
problem in implementing a sludge landfill operation.
                                     1-6

-------
    A landfill has a finite size and, therefore,  a finite operating life.
This operating life must be long enough to justify purchase,  site preparation,
and other capital costs, which become less significant when amortized over
time.

    A landfill's lifespan can be estimated by dividing the volume of sludge it
can hold by the volume of sludge landfilled each year.  Landfill capacity is
the product of the usable fill area  (generally 50-70% of the total site
surface area) times the depth of the landfill.  The remaining 30-50% of the
site is used for buffer zones, access roads, and soil stockpiles.  In
calculating landfill size requirements, the projected increase in sludge
volume during the lifetime of the site must be considered.  This volume will
be a function of community growth and the construction of additional
wastewater treatment capacity.  Soil is often used to increase the solids
content of a sludge and to provide interim and final cover.  Bulking and cover
soil may be present on site and readily available from trench excavation.  If
sufficient soil is not available on  site, or if its physical and chemical
properties are not suitable, soil may have to be hauled to the landfill, a
costly procedure.

    Pollution of ground and surface waters are the major environmental
concerns associated with monofilling.  The depth to ground water, the type of
bedrock, and the soil environment affect the potential for groundwater
contamination.  Any currently used or potentially potable ground water should
be protected from landfill leachate.
1.6 STORAGE

    Storage space to accomodate at least several days' production of sludge
should be provided at the treatment plant in case transportation or labor
problems prevent hauling sludge to the landfill site.  Onsite storage also is
desirable in case inclement weather or other problems disrupt site operations
                                      1-7

-------
These disruptions can be minimized if special  fill  areas  close  to  the landfill
entrance are designated for use only during inclement weather.
1.7 GOOD PRACTICES
    Proper sanitary landfill site planning  and management  procedures  will
minimize the potential for leachate  formation and migration;  methane
generation; and surface runoff,  erosion,  and siltation.
1.8 SLUDGE QUALITY

     The physical characteristics  of  sludge are  important  for monofilling.
Sludges should be stabilized,  dewatered,  and mixed with bulking  agents  to
facilitate handling.   The chemical characteristics of sludge, however,  have
rarely been of concern.   Chemical  composition has been important only  if a
sludge is classified as  hazardous  under  the Resource Recovery Conservation Act
(RCRA).   For this reason,  prior  to the proposed  sewage sludge regulations,
sludges that were too highly contaminated for other use/disposal options, but
not contaminated enough  to be  classified as hazardous, were monofilled.
                                    1-8

-------
                                SECTION TWO
                     RISK ASSESSMENT METHODOLOGY
2.1  INTRODUCTION

    The Environmental Criteria and Assessment Office in the Agency's  Office of
Research and Development (ORD) has developed detailed risk assessment
methodologies for four sludge disposal options:   land application/distribution
and marketing, landfilling,  incineration,  and surface disposal.    This  section
discusses the methodology used to model risks associated with sludge-only
landfills or monofills and to develop risk-based maximum allowable
concentrations for contaminants in sewage  sludge disposed in monofills.

    The first step in developing the risk  assessment methodology for  sludge
monofills was to identify the major pathways of exposure through which  each
sludge contaminant could reach and detrimentally affect humans,  plants,  or
animals.  Mathematical expressions (algorithms)  were then developed to
describe the transport, fate, and effects  of the pollutants in each medium
(air, water, soil)   Site-specific factors that influence exposure and
toxicity, such as soil or climatic variability and management practices,  were
also incorporated in the algorithms.   The  risk assessment methodology was
peer-reviewed internally by the ORD and externally by the Agency's Science
Advisory Board (SAB) and then translated into computerized mathematical models
by the Office of Water Regulations and Standards (OWRS)

    The set of computer models that incorporates this methodology,
collectively known as SLUDGEMAN, can estimate the risk associated with  sludge
disposal in a given landfill.  SLUDGEMAN is designed to calculate a reasonable
worst-case level of exposure to chemicals  leaching from a landfill and  emitted
to the atmosphere.
                                      2-1

-------
2.2  IDENTIFICATION OF PATHWAYS OF EXPOSURE AND HEALTH AND
     ENVIRONMENTAL CRITERIA

     SLUDGEMAN predicts the movement of pollutants  from a  source  landfill
through several environmental pathways to  reach  a  nonhuman target organism or
a  most-exposed individual (MEI)  defined as  an adult with  a 70-year (yr)
exposure to long-term average contaminant  levels released from a landfill near
his  or her residence, at a calculated concentration.   This calculated
pollutant concentration is compared to either an environmental impact
criterion or a human health criterion to determine the risk of disease  to the
MEI.  The following sections describe the health environmental criteria,
identified before the risk-assessment methodology  was  developed,  and the  key
pathways of exposure, identified during that  development  process.
    2.2.1  Pathways of Exposure

    Four environmental pathways were identified  as  critical  to  the  analysis  of
sludge monofills:

    •  Contaminant infiltration to  ground water
    •  Vapor loss  from fill material
    •  Surface runoff
    •  Suspension  of contaminated particles  from the working face

Figures 2-1 to 2-3 show routes  of human  exposure from  landfilled sludge  and
contaminant migration pathways  for  narrow- and wide-trench landfills.  The
first two pathways were identified  as  the key pathways  of contamination  and
were modeled in EPA's SLUDGEMAN model.

    Infiltration of sludge contaminants  to ground water and  subsequent
ingestion of this  water by humans was  considered the most significant  of the
potential pathways, based on the likelihood  of occurrence.   The MEI  for  this
groundwater pathway was defined as  an  adult  residing at the  property boundary
                                     2-2

-------
    Alrborn*
    Pollution
                      Vapor
                                 Landflllad
                                  Sludg*
                          Olssolvcd In
                           Laaenat*
                                Unsaturatad
                                   Soil
                      Olssolvad
                     Pvtlcuiatasr
                                                              Runoff
                        Dlsxolvad and
                        Attacncd to
                      Susp«na»d Matter
        Human

       S*<"»u"
     Crop/Uv«stoek
      Consumption
      Saturatad
     around watar
                            Drinking
                            Watar
Irrigation/
UvastocK
 Watar
                                                Racharg*
                                                               Body
                                               Withdrawal
                                                for Us*
FIGURE 2-1.   Routes to Human Exposure from Landfilling Sludge
                               2-3

-------
ho
I
.(S
                                                                        W»Ur TabU
                          FIGURE 2-2.  Contaminant Migration Pathways for Narrow Trench Landfills

-------
    (T) Va|»oi
        ~ V\r V
IK.UUI, 2-.^.  Oiiilamiiianl Migration I'atliways lor I'it or Wide Trench l^ndfillls

-------
of the landfill who drinks 2 liters (L)  of the ground water every day for his
or her entire 70-yr lifespan.

    Vapor loss of volatile compounds is  also a very likely source of
contamination.  Vapor loss may be caused by volatilization from the uncovered
working face of the landfill or contaminant releases from within the fill and
subsequent migration of these contaminants through the soil cover.  Vapor loss
from sewage sludge landfills was identified as a possible source of
contamination from benzene, cyanide, dimethylnitrosamine,  and
trichloroethylene.  The ME I for the vapor pathway was defined as an adult
residing at the property boundary of the landfill who inhales vapors from the
site 24 hours (hr) a day for his or her  entire 70-yr lifespan.

    The third pathway, surface runoff,  is one of the least likely routes of
exposure because:

    •  Soils are used for cover, making  the working face the only significant
       source area for contaminated runoff.
    •  At landfills where the working face is below the grade of the
       surrounding areas, runoff will be contained by the facility design.
    •  Where the working face is not below grade, the regulation requires
       that drainage be contained in the downflow direction (runon controls)

    The fourth pathway, suspension of contaminated particles from the working
face, is also an unlikely route of exposure because the face of the fill will
not be exposed for more than 8-12 hr/day and because threshold wind speeds
necessary for suspension rarely would be exceeded for any length of time.
This pathway, as well as the surface runoff pathway, is not modeled by
SLUDGEMAN.
    2.2.2 Human Health and Environmental Impact Criteria

    The criteria used in the  risk assessment methodology were derived from
different sources,  depending  on the type of pollutant:
                                     2-6

-------
    •  For noncarcinogens,  the human health criterion is the daily intake of a
       pollutant that will  cause no adverse effect;  it is considered a
       threshold value for  that contaminant.   The model uses the Agency's
       established Risk Reference Doses (RfDs) for humans as the threshold
       values for chronic toxicity.

    •  For plants and animals, the model uses chronic toxicity threshold
       values reported in the scientific literature.

    •  For carcinogens, no  dose is considered "safe"; only a zero dose is
       associated with zero risk.  The Agency's Carcinogen Assessment Group
       has estimated the carcinogenic potency (i.e.,  the slope of the curve
       plotting risk versus exposure) for humans exposed to low-dose levels
       of carcinogens (EPA, 1987a).  These potency values are used in the
       model to derive the  exposure level expected to correspond to a given
       level of excess risk.   Incremental risk levels of 10"* (one additional
       cancer case in one million people) to 10"4 (one additional cancer case
       in ten thousand people) were evaluated for the proposed sewage sludge
       regulation.

    •  Maximum Contaminant  Levels  (MCLs) established by EPA's Office of
       Drinking Water are used as the drinking water criteria for the
       groundwater contamination pathway

    •  For the seven groundwater pollutants that have no proposed MCLs, the
       target concentrations  were either the carcinogenic potency (qj*) values
       associated with specific risk levels for the MEI, or the RfD.


SLUDGEMAN back-calculates the maximum allowable pollutant concentrations that
would yield the RfD,  MCL, or  appropriate carcinogenic dose at the exposure
point for the MEI or target organism.
2.3  OVERVIEW OF SLUDGEMAN



    SLUDGEMAN incorporates a number of computer models and submodels that are

designed to represent the leaching of contaminants from a source and the fate

and transport of the leached material through a zone of unsaturated soil

(where the spaces between soil particles are filled with both air and water)

and into and through a saturated zone, typically considered an aquifer.   The
                                     2-7

-------
model also predicts the release of volatile contaminants into the atmosphere.
SLUDGEMAN's major components are:

    .  Two models that determine the rate at which each contaminant of  concern
       leaches from the monofill (SATM1 and SLUGMAIN)
    •  A model that determines the rate of contaminant transport through  the
       unsaturated zone and the processes that occur in this zone to degrade
       contaminants or retard transport (CHAIN)
    •  A model that predicts the transport and fate of contaminants in  the
       saturated zone (AT123D)
    .  A model that integrates CHAIN and AT123D (AT123DIN)
    •  Two models (SATIT and ALLCON) that (1) calculate the rate of release to
       and the concentrations of volatile contaminants in the atmosphere  and
       (2) determine the allowable concentration of contaminants in sludge
       using the results of both the groundwater and vapor pathway modeling

    Section 2.4 discusses the methodologies incorporated in the five major
groundwater models (SATM1, SLUGMAIN, CHAIN, AT123DIN, and AT123D),  Section 2.5
discusses the two vapor release models, and Section 2.6 presents the
methodology used to back-calculate maximum concentrations of contaminants in
sludge based on the criteria and the predictions of the SLUDGEMAN models
Finally,  Section 2.7 presents a summary of the comments generated by SAB's
review of SLUDGEMAN and EPA's responses to those comments.

    SLUDGEMAN performs two types of analyses using the component models  listed
above.  For monofills located over Class I aquifers, SLUDGEMAN uses SATM1,
CHAIN, and SATIT to predict groundwater concentrations and vapor loss and to
back-calculate allowable concentrations of contaminants in sludge.   The  Class
I aquifer analysis assumes the leachate is not transported in the aquifer, but
is ingested by the MEI in the same concentration at which it enters the
aquifer.   Thus AT123D, which models transport through the saturated zone, is
not used.   Class I aquifers are treated very conservatively because they  are
highly vulnerable to contamination, being either irreplaceable as sources of
drinking  water to substantial populations or ecologically vital.
                                     2-8

-------
    For monofills located over Class II aquifers (ground water that is not
classified as Class I, and that either is used currently or is available as a
potential source of ground water), the model uses SLUGMAIN instead of SATM1 to
calculate leach times.  The model for monofills over Class II aquifers also
uses the saturated zone transport model AT123D and the unsaturated transport
model CHAIN.  Additionally, the ALLCON model, rather than SATIT, is used to
predict volatile contaminant concentrations in the atmosphere and to calculate
allowable sludge concentrations.  During transport in the saturated zone
(aquifer),  contaminants can be diluted or degraded; thus the criteria
generated are less stringent than those generated using the Class I analysis.

    A few additional analytical distinctions are made in modeling the two
types of monofills.  For monofills located over Class II aquifers, SLUDGEMAN
calculates downgradient pollutant concentrations on the centerline of the
monofill rather than on the edge of the monofill, because the highest
pollutant concentrations are expected along the centerline.  The model also
assumes the monofill is contiguous to one edge of the aquifer, so that
pollutants are modeled to disperse laterally into the center of the aquifer
from the edge.  This approach yields higher downgradient concentrations than
those calculated assuming the monofill were centered in the aquifer with
lateral dispersion occurring in both directions toward the sides   The
assumption that the monofill is located contiguously to one edge of the
aquifer is realistic because monofills can be placed in any location relative
to an aquifer, including near one edge.

    Monofills can be located over other types of aquifers, including Class
IIIA and IIIB aquifers and their subclassifications.   SLUDGEMAN does not
distinguish monofills located over Class IIIA and IIIB aquifers from those
over Class II aquifers because Class III aquifers also are not used as sources
of drinking water.  Class IIIA aquifers yield insufficient water or have
solids content greater than 10,000 milligrams (mg/L).  Class IIIB aquifers are
contaminated naturally or by human activity and cannot be cleaned up using
reasonable water treatment methods.
                                      2-9

-------
2.4  DESCRIPTION OF THE GROUNDWATER COMPONENTS OF THE
     SLUDGEMAN MODEL

    SLUDGEMAN's groundwater components  consist  of  a  number  of sequential
models that vary depending on the type  of aquifer  to be  modeled.   These models
include leachate pulse-time calculations  (SATMl and  SLUGMAIN),  an unsaturated
zone fate and transport model (CHAIN) ,  a  saturated zone  fate  and  transport
model (AT123D),  and a model that integrates  CHAIN  and AT123D  (AT123DIN).   A
discussion of each of these models follows.
    2.4.1  Pulse-time Calculation (SATMl and SLUGMAIN)

    Leaching of contaminants out of a monofill  does  not  happen instantly   The
leachate pulse time is the length of time  from  the beginning  to the  end of
leaching, i.e., when all leachable materials  have migrated from the  monofill.
The SATMl model is used to calculate the pulse  time  in Class  I aquifer
simulations; SLUGMAIN is used to calculate pulse time  in Class II  aquifer
simulations.  The input data required for  these calculations  include:
concentrations of pollutants in the leachate, concentrations  of pollutants in
the sludge  (dry weight), sludge moisture content, sludge storage capacity,
sludge density, net recharge rate,  width and  length  of the landfill,  and
height of the fill material.  These parameters  and assigned values are
discussed in detail in Section 3.

    Several assumptions are made in calculating pulse  time:   (1) the estimated
leachate concentrations are an approximation  of leachate strength, (2) all the
contaminants ultimately solubilize,  and  (3) the leachate pattern is  a pulse of
equal height throughout its duration (i.e., a square wave,  rather  than a curve
representing a gradual increase followed by a gradual  decline in the amount of
contaminants leaching from the monofill).  The  results of the pulse-time
calculation are used as an input to CHAIN, which calculates contaminant
concentrations in the unsaturated zone.  The  parameters  total contaminant
                                     2-10

-------
levels in the sludge, contaminant concentrations  in  the  leachate,  sludge
moisture content, and recharge rate are used  to calculate pulse  time.   These

factors are relevant to pulse time according  to:


                 Q  = M/X                                          (1)

and

                 Q  = RT  +  (L - S)                                (2)


where  Q =  volumetric water flow of leachate per  square meter  (m2) required
            for  the contaminant  to be completely  leached; the units  for Q  are
            in m3

       R =  recharge of infiltrate volume  entering the landfill,  in  m2/yr.
            This can be calculated as:  R  = P   ET  RO, where  P  is
            precipitation, ET is evapotranspiration  loss, and RO  is  runoff

       S =  storage capacity for water  in  sludge,  defined as the  "dry"  water
            content per m2 for the  sludge under normal atmospheric conditions,
            i.e.,  the product of fill height  after drainage, sludge  density,
            and  moisture  content divided by 1,000  kilograms  (kg)/m3

       L =  water  content of sludge per m2 at  time of disposal,  i.e.  , the
            product of fill height, sludge density,  and moisture  content
            divided by 1,000 kg/m3;  the units  for L are in m3

       T =  the  pulse time over which all  contaminant will be released  from
            the  sludge, in yr

       M =  mass of contaminant  contained  in  a volume of sludge
            represented by the height of the  sludge  in the -fill  and  a m1 cross
            section, i.e., M =  (height  of  fill x  1.0 m3)  x (density of sludge,
            kg/m3)  x (concentration of contaminant in sludge,  kg/kg)  x  (1
            moisture content); the units for  M are in kg

       X =  concentration of leachate contaminant  in kg/m3


All of these parameters are discussed more fully  in  Section  3.


    When equations 1 and  2 are combined, the  pulse time T can be  calculated:


                  T  -  M - X(l  - S)                               (3)
                            XR
                                       2-11

-------
    For degradable contaminants,  the initial mass of contaminant, M, changes
with time.  If a first-order decay mechanism is assumed at a degradation rate
d, the equation becomes:
                     =  -1 [In   XR  1                                 (4)
                        d    XR - dM
where  T = pulse time,  yr
       d = degradation rate constant,  yr"1
       X = leachate concentration,  kg/m
       R = recharge rate,  m3/yr
       M = mass of contaminant in sludge,  kg
    2.4.2  Unsaturated Zone Model (CHAIN)

    CHAIN is the analytical model used to solve the one-dimensional
convective-dispersive transport equation for the unsaturated zone (Van
Genutchen, 1985).   This model predicts the way dispersion elongates the
leachate pulse as it moves through the unsaturated zone,  resulting in
decreasing contaminant concentrations.  The CHAIN model itself is composed of
several submodels.   These submodels calculate the length of time it takes the
leachate to travel through the unsaturated zone to the saturated zone below,
and the rates of retardation and degradation of contaminants in the
unsaturated zone.   Length of travel time, retardation, and degradation
calculations used in the CHAIN model are discussed below.

    The MINTEQ model, which predicts the fate of dissolved metals, is also
discussed in this section.   MINTEQ, which is not part of CHAIN, was run
separately,  and the results were used to adjust the metals concentrations
predicted by CHAIN to account for precipitation of metals from the leachate.
These adjustments are "hard-wired" into the CHAIN model and do not need  to be
input.
                                       2-12

-------
    2.4.2.1  Travel-time Calculation

    The unsaturated zone consists of the layers of soil between the  landfill
and the uppermost aquifer.  To determine the concentration of a contaminant at
the base of the unsaturated zone, the travel time must be calculated.  The
travel time is the length of time it takes the leachate to travel through the
unsaturated zone; it is determined using the depth to ground water and the net
recharge rate.

    Two basic approaches can be used to determine travel time in the
unsaturated zone:  (1) analytical models and (2) unsaturated flow models.
Both approaches are based on the same fundamental equations but differ in the
simplifying assumptions made to solve the equations.  Analytical models
require fewer data, are computationally easier to use, and generate  solutions
much more rapidly than unsaturated flow models.  Consequently, the Agency
selected an analytical model to predict unsaturated zone concentrations  of
contaminants.  Analytical models, however, require the assumption of  steady-
state conditions.  As a result, they predict a constant contribution  of
leachate over time rather than the periodic storm event contributions that
actually occur.  This simplifying assumption generally leads to results  that
overpredict velocity, underpredict travel time and degradation, and
overpredict concentrations in the unsaturated zone.

    Analytical solutions of travel time through the unsaturated zone  are based
on Darcy's law for one-dimensional flow.  Darcy's law is a mathematical
description of water flow through a porous medium, and is given in terms of
the following equation:

             V, = K ty/J 5fe>                                            (5)
                         <5z
where  Vz       =  seepage velocity in the vertical direction
       lJm      =  matric potential (suction head or negative pressure head)
               =  hydraulic conductivity as a function of matric potential
               =  hydraulic gradient in the vertical direction
                                     2-13

-------
    In unsaturated flow,  both hydraulic conductivity and moisture content are
nonlinear functions of pressure head.   Hydraulic conductivity, moisture
content, and pressure head need not be constant throughout a soil column;
however, if they are not, a direct analytical solution of Darcy's equation is
not possible for unsaturated flow.  To solve Darcy's equation for travel time
in the unsaturated zone,  the following assumptions must be made:

    •  There is one-dimensional flow in the vertical direction.
    •  Water flow is steady state.
    •  Water table conditions exist at the lower boundary.
    •  The upper boundary has a constant flux.
    •   Soil characteristics (moisture content versus matric potential and
       hydraulic conductivity versus matric potential) are constant with
        depth.
    •   The hydraulic gradient is sloped vertically downward and equals unity
        (drainage is caused strictly by gravity, or 6p>/6z = 0)

For nonhomogeneous soils, the constant property assumption can be approximated
by dividing the soil profile into a series of layers,  then calculating travel
time for each layer individually.

    The unit gradient assumption greatly simplifies the analysis.  Under this
assumption matric potential and, therefore, moisture content and hydraulic
conductivity, remain constant with depth.   When this assumption is made,
moisture content can be solved directly in terms of flux through the system
and saturated soil properties.  When the moisture content and flux are known,
the pore water velocity and the travel time through the unsaturated zone can
be calculated.   The unit gradient assumption generally is valid if
gravitational forces dominate other forces (e.g., capillary forces).

    If the unit assumption is not made, the analytical solution to
unsaturated flow becomes more complex.  In this case,  calculations for
pressure head and moisture content must be solved iteratively.  Deriving
                                      2-14

-------
iterative solutions is a time-consuming task, but can be simplified by using a
computer.

    All analytical solutions for travel time through the unsaturated zone are
one-dimensional.   When applying these solutions to specific sites, the
horizontal variability of soil characteristics must be considered.  If soil
characteristics vary spatially, the solution should be applied to the soil
profile having the highest hydraulic conductivity.  The solution will then
yield the highest velocity and shortest travel time (i.e., worst case) for the
unsaturated flow system.  The solution, which is the water travel time (TW),
must then be modified by a retardation factor.  A more detailed treatment of
the theory and equations used in travel time calculations may be found in the
Technical Guidance Manual for Calculating Time of Travel (TOT) in the
Unsaturated Zone (EPA, 1985c).
    2.4.2.2  Retardation Factor

    Contaminants will  travel  either with the leachate or at a slower velocity
depending on the degree to which they are adsorbed onto soil particles.
Retardation is a measure of how slowly a contaminant moves through the
unsaturated zone with  respect to the bulk of the leachate.  The retardation
factor is calculated from model input data on the bulk density of the
unsaturated zone material, the partition coefficient of the contaminant,
hydraulic conductivity, effective porosity, effective bulk density, slope of
the curve plotting matric potential versus moisture content, and the saturated
moisture content of the unsaturated zone material.  These input parameters and
their assigned values  are discussed in Section 3.

    The retardation factor (R) for a particular contaminant can be calculated
by the equation:

             R =  1   + (B/9XK,)                             (6)
                                     2-15

-------
where   B/9 = soil-to-solution ratio (bulk density of the soil divided  by
              its effective porosity)
        Kd   = distribution coefficient

Kj can be measured in the  laboratory or obtained from the literature for  a
wide range of soil types and contaminants.  Values for K<, are discussed in
Section  3.
    2.4.23 Degradation

    The travel time for a contaminant through the unsaturated zone  (TC)  can be
estimated as the water travel time (TO) , derived in the travel  time
calculation, times the retardation factor for that particular contaminant,  as
represented by:

             TC = TW x R                                            (7)

    Reductions in pollutant concentration due to degradation processes,  such
as hydrolysis and biochemical oxidation are characterized by a  degradation
constant, d.  This constant can be related to the environmental half-life of a
pollutant, represented by tV2, the time  required for the contaminant
concentration to be reduced to one-half its initial value.  If  a  first-order
decay mechanism is assumed,  the concentration X at any time can be  defined  as:

             X = X,, e-*                                               (8)

where  X,,  =  the initial concentration  of X
       t  =  time

Therefore, the half-life,  tm, can be derived as:
                                      2-16

-------
             in 2L
                A.
or
                 =  In2                                               (10)
                     d
    Equation 8 can be used to determine the degree of degradation that will
occur as the leachate moves through the unsaturated zone.  In this way, the
leachate concentration from the source, X, can be converted to the value
predicted at the point where the leachate enters the aquifer.  This conversion
is accomplished by inserting the contaminant travel time in the unsaturated
zone, TC ,  into Equations 7 and 8:
             X  =  Xe^0                                             (11)
or
                      (-InZTC)
             X  =  Xe"1^

    The resulting value for X is the contaminant concentration that should be
applied to all subsequent saturated zone transport calculations .   The above
equation gives the pollutant concentration reduction in the unsaturated  zone
caused by degradation.  That is, the calculation conservatively assumes  that
the contaminant plume moves as a pulse through the unsaturated zone, with no
dispersion.  In actuality, dispersion elongates the contaminant pulse as it
moves through the unsaturated zone, with a resulting decrease in
concentration .
   2.4.2.4 Metals Modeling (MINTEQ)

    After CHAIN is used to determine contaminant concentrations at a depth
equal to the depth to ground water for a period of several contaminant travel
                                     2-17

-------
 times, the concentrations of metals must be adjusted to account for  any
 precipitation of metal compounds that exceed solubility limits.  The MINTEQ
 model  is used to calculate -the mass distribution of a dissolved metal between
 various uncomplexed and complexed aqueous species and to predict the
 precipitation and dissolution of these species (Felmy et al., 1984).  MINTEQ
 was run for a wide range of conditions, and the results were programmed  into
 the Agency's landfill model.

    When the pH and Eh (oxidation-reduction potential) of the ground water  are
 known, CHAIN can automatically adjust metal concentrations at the base of the
 unsaturated zone using the MINTEQ calculations for those conditions.  After
 these  adjustments are made, CHAIN compares the maximum concentrations of
 metals and organic contaminants to the drinking water criteria.  For Class  II
 groundwater analyses, if the maximum concentrations are below the criteria,
 the modeling analysis can be concluded without analyzing saturated zone
 transport.  If the predicted concentrations exceed the criteria, then
 contaminant transport in the ground water must be simulated.
    2.4.3  Saturated Zone Model (AT123D)

    Analytical solutions and numerical modeling are the two basic approaches
for estimating contaminant travel time and concentrations in saturated
groundwater flow systems.  The Agency selected an analytical groundwater
model, AT123D, because this approach requires fewer data, is less time
consuming to establish and run,  and requires no expensive equipment or
specialized expertise.

    AT123D is the analytical model used to solve the advective-dispersive
transport equation for the saturated zone (Yeh, 1981)   Advection accounts for
the movement of solutes with the mean velocity of the water   Dispersion of
the leachate plume occurs because solutes travel more slowly near the walls of
the soil pores than in their centers and faster in larger pores.  Molecular
diffusion also is included in AT123D to account for spreading of the leachate
                                     2-18

-------
plume due to random molecular motion.  Additionally, AT123D calculates the
sorption and decay of contaminants.  Input data required for the model include
the type of material in the saturated zone, mixing thickness of the aquifer,
hydraulic conductivity, effective porosity, hydraulic gradient, effective bulk
density, width of the saturated zone, partition coefficients, decay rates,
background groundwater concentrations for each contaminant, and the distance
to the compliance point.  The algorithms incorporated in this model are not
presented here.  The interested reader can find a discussion of the highly
complex mathematical expressions used to model saturated transport modeling in
Yeh (1981).  The parameters used as  input to the model and their assigned
values are discussed in Section 3.

    The Agency's goal is to field-validate all the risk-based models used to
support the proposed rule.  AT123D has not yet been field-validated, but the
theory behind the model is well known and accepted by groundwater experts, and
it is widely used by the Agency to support regulations and investigations by
EPA's Office of Toxic Substances and Office of Solid Waste.
    2.4.4  Integrating the Unsaturated and Saturated Zone Models (AT123DIN)

    To  integrate between the CHAIN unsaturated  zone model and the AT123D
 saturated zone model, the contaminant concentrations  output  from CHAIN must be
 converted to mass flux  rates from an appropriate repository.  The repository
 is defined as the area  below the landfill to a  depth  in the  aquifer equal  to
 the mixing depth of the leachate from the landfill.   The amount of contaminant
 mass leaching into the  aquifer annually is the  concentration of each
 contaminant times the recharge rate times the area of the landfill.  The
 annual mass flux exiting the area below the landfill  is either the total
 annual mass flux, if the groundwater flow rate  is sufficient to carry the
 total mass of leachate  away each year, or a fraction  of this amount equal  to
 the fraction of the landfill length that the ground water travels in a year.
 The mass flux from the  area below the landfill  is therefore  equal to the
 contaminant concentration times the recharge rate times the  landfill width
                                      2-19

-------
times the minimum of the landfill length  and  the  groundwater velocity.   The
result of this calculation is the mass  flux value needed  as input to AT123D.

    If the groundwater flow is insufficient to  carry  away all  the contaminant
leachate that enters the aquifer each year, then  the  release time for
contaminants into the aquifer is increased by the ratio of the length of the
landfill to the annual groundwater travel distance.   This adjustment accounts
for the increased length of time required to  wash away all contaminants from
beneath the landfill.
2.5 DESCRIPTION OF THE VAPOR PATHWAY COMPONENTS OF THE
    SLUDGEMAN MODEL

    Vapor loss from landfills has been identified as  a  potential problem for
certain volatile toxic chemicals such as  benzene,  cyanide,
dimethylnitrosamine,  and trichloroethylene.  To  estimate  landfill vapor loss,
the Agency is using (in SATIT and ALLCON)  the  same analytical  model that was
developed to evaluate vapor loss and dispersion  of contaminants from hazardous
waste sites in the landfill ban analysis  (Environmental Science and
Engineering, 1985).  The vapor loss models consider three periods:   (1) the
operating period with uncovered wastes,  (2)  the  period  of shallow temporary
cover, and (3) the post-closure period with permanent cover.   The models
assume that pollutants will evaporate from the monofill for a  total of 70 yr.
The monofill is assumed to be active for  20 of those  70 yr,  during which the
sludge deposited each day is assumed to remain open to  the air for an average
of 4 hr.   The sludge  is therefore assumed to be  open  to the air 1/6th of the
time for the first 20 years, covered with a temporary cover for 5/6ths of that
time,  and covered with a final cover for  50 yr.   Degradation and deposition
are not considered because travel times are relatively  short and the Agency
wanted to be conservative in estimating potential vapor concentrations.

    For the operating period, during which wastes remain  uncovered, the model
assumes that volatilization depends directly on  wind  speed.  The model
                                     2-20

-------
predicts the maximum possible exposure to vapor concentrations because it
assumes that (1) wind speed and direction are constant, (2) stable atmospheric
conditions prevail, and (3) the receptor is located downwind and along the
centerline of the plume.

    For the two periods when wastes are covered, the model assumes that the
loss rate of contaminants  is independent of wind speed and is controlled by
diffusion of contaminants  through the soil.  The model assumes that the final
soil cover applied to a landfill cell has the same permeability as that of the
temporary soil cover.  In  practice, because the final soil cover is usually
less permeable, the model  assumption leads to an overprediction of loss rates

    The rate at which pollutants evaporate from a monofill is estimated using
Henry's law constants, a method that also leads to overprediction.  Henry's
law states that the mass of any gas that dissolves in a given volume of liquid
at constant temperature is directly proportional to the pressure that the gas
exerts  above the  liquid.   The use of Henry's law can be avoided if adequate
data specifying the vapor  pressure of each contaminant are available.  Because
vapor pressures are not measured routinely, the model uses Henry's law to
specify vapor concentration as a function of liquid concentration.  Henry's
law is  most appropriate for low concentrations of dissolved pollutants and low
solids  content sludges.  As pollutant concentrations and solids content
increase, Henry's  law tends to overpredict vapor pressure as a result of
activity effects  and partitioning between solid and liquid phases.

    The models are written to calculate vapor concentrations for six of the
ten organics of concern:   benzo(a)pyrene, bis(2-ethylhexyl)phthalate,
chlordane, DDT/DDD/DDE, dimethylnitrosamine, and polychlorinated biphenyls
(PCBs).  Dimensionless Henry's law constants and molecular weights have been
incorporated into the model for these chemicals.

    In  addition to Henry's law constants and the molecular weight of
contaminants, other input  data are required for the vapor loss models,
including average wind speed and air temperature, porosity of cover soil,
                                     2-21

-------
times the minimum of the landfill  length  and the  groundwater velocity.   The
result of this calculation is  the  mass  flux value needed as  input to AT123D.

    If the groundwater flow is insufficient to  carry  away all the contaminant
leachate that enters the aquifer each year,  then  the  release time for
contaminants into the aquifer  is increased by the ratio  of the length of the
landfill to the annual groundwater travel distance.   This adjustment accounts
for the increased length of time required to wash away all contaminants from
beneath the landfill.
2.5 DESCRIPTION OF THE VAPOR PATHWAY COMPONENTS OF THE
    SLUDGEMAN MODEL

    Vapor loss from landfills has  been identified  as  a  potential problem for
certain volatile toxic chemicals  such as  benzene,  cyanide,
dimethylnitrosamine,  and trichloroethylene.  To  estimate  landfill vapor loss,
the Agency is using (in SATIT and  ALLCON)  the  same analytical  model that was
developed to evaluate vapor loss  and dispersion  of contaminants from hazardous
waste sites in the landfill ban analysis  (Environmental Science and
Engineering, 1985).  The vapor loss models  consider three periods:   (1) the
operating period with uncovered wastes,  (2)  the  period  of shallow temporary
cover, and (3) the post-closure period with permanent cover    The models
assume that pollutants will evaporate from  the monofill for  a  total of 70 yr.
The monofill is assumed to be active for  20 of those  70 yr,  during which the
sludge deposited each day is assumed to remain open to  the air for an average
of 4 hr.   The sludge  is therefore  assumed to be  open to the  air l/6th of the
time for the first 20 years, covered with a temporary cover  for 5/6ths of that
time,  and covered with a final cover for  50 yr.  Degradation and deposition
are not considered because travel  times are relatively  short and the Agency
wanted to be conservative in estimating potential  vapor concentrations.

    For the operating period,  during which  wastes  remain  uncovered, the model
assumes that volatilization depends directly on  wind speed.   The model
                                     2-22

-------
Therefore, the limiting leachate concentration must be related back  to  a
limiting sludge concentration.

    For organic contaminants, the relationship between their concentrations  in
sludge and their concentrations in leachate is defined by the distribution
coefficient Kj.   This coefficient  defines a constant relationship between the
sludge concentration  (Sc)  and the  leachate concentration  (L,,) such that
Sc = L,. x Kj.   The partition coefficient K^ and its derivation are discussed in
Section 3.  With Kj and the limiting leachate  concentration (L,.,)  determined by
the model, the limiting sludge concentration  (Sci) is calculated from Sd = Kd  *
    For metal constituents, the relationship between contaminant concentration
 in sludge and that  in  leachate is more difficult to define.  Metal
 concentrations  in leachate are often defined by solubility constraints  rather
 than by partitioning.   In this case, leachate levels will stay at the
 solubility  threshold regardless of  the sludge concentration.  It is  the
 duration of the  release of metals at the solubility limit that affects  the
 outflow concentration  at a monitoring point.  Given a constant recharge  rate,
 chemical release time  is governed by sludge pollutant concentration.  The
 higher the  sludge pollutant concentration, the longer the chemical is
 released, and the more  the outflow  concentration approaches the leachate
 concentration or solubility limit.  The model conventionally assumes  that the
 highest reported effluent or  leachate value for the metal constituent defines
 the solubility  limit.   The sludge concentration can then be varied to
 determine the inventory of contaminants producing maximum acceptable  dose
 levels at the point of  exposure.

    Different types of  sludges will affect a metal's chemistry differently
 and, therefore,  its maximum solubility level in leachate.  To accommodate this
 sludge-specific  factor,  a leachate  test can be conducted to determine
 empirically  the  actual  leachate concentration.  Then the relationship derived
 from the sludge's total contaminant level and the leachate concentration can
                                     2-23

-------
be used to convert the limiting leachate concentrations to a sludge criteria
for that site.

    For some metals, the back-calculation is not straightforward due  to
complicated geochemistry.  Also, the sorption characteristics in the  aquifer
are not linear.  The relationship between the dry-weight concentration of  a
pollutant in the sludge and the final concentration at the point of compliance
is therefore nonlinear.

    Because of this nonlinear relationship,  an iterative approach is  required
to solve for the allowable dry-weight concentrations in sludge.  For  the
iterative process, an initial set of typical dry-weight concentrations are
input into the model.  Using these inputs,  the model then calculates  output
concentrations at the point of compliance,  which are compared to the  human
health criteria for each pollutant.   The dry-weight concentrations for each
pollutant are then adjusted appropriately,  and ALLCON writes the new  dry-
weight concentrations to a new input file to be used in another model run.
The model is rerun, the new results  are compared to the human health  criteria,
the dry-weight concentrations are adjusted again,  and a new input file is
written.  After several such model runs, the output concentrations of
contaminants should approach the human health criteria and the dry-weight
concentrations of contaminants should approach the allowable sludge dry-weight
concentrations.

    If no upper limit to the dry-weight concentration for a given pollutant
appears to be generated,  the model limits the dry-weight concentration to
10,000 mg/kg (1% pollutant by weight,  a reasonable upper limit).  This step
prevents the model from spending needless time calculating unreasonable dry-
weight concentrations of contaminants in cases, for example, in which the
leachate concentration of a pollutant is less than its human health criterion.
                                     2-24

-------
    2.6.2 Vapor Pathway Calculation

    Because total pollutant concentrations at the point of compliance are
required, the calculated vapor concentration must be added to the calculated
leachate and background concentrations of the groundwater pathway for each
pollutant.   The model calculates vapor concentrations in mg/m3, whereas  liquid
concentrations are calculated in mg/L.  Therefore, the vapor concentrations
must be converted to equivalent liquid concentrations before they can be
summed to produce a total concentration for comparison with the human health
criterion.

    The model assumes that a 70-kg person breathes about 20 m3  of  air per  day
and drinks about 2 L of water per day.  Thus, if the air contains 1 micrograms
(Mg)/mJ of  a  pollutant,  the person  is  breathing  20 Mg  of  the  pollutant per
day.  Because the person is assumed to drink 2 L of water per day, inhaling 20
Mg of a contaminant daily is equivalent to drinking water containing 10 Mg/L
of that contaminant.  Ten Mg/L is equivalent to 0.01 mg/L.  Thus,  1 MS/™3
vapor concentration is equivalent to 0.01 mg/L liquid concentration.  Under
these assumptions, the model multiplies the vapor concentration in p>g/m3 by
0.01 to covert  to equivalent liquid concentrations in mg/L.  The pollutant
concentrations  then can be summed for comparison with the human health
criterion.
2.7 SCIENCE ADVISORY BOARD REVIEW

    The SAB reviewed the groundwater and vapor modeling used in SLUDGEMAN.
The SAB had four major recommendations regarding the groundwater modeling:

    •  The unsaturated zone should be modeled with PRZM (another unsaturated
       zone model) instead of CHAIN.
    •  The unsaturated zone should be modeled assuming anaerobic conditions.
    •  The model should be modified to simulate the effect of liners.  »k
                                     2-25

-------
    •  The model should be expanded to include the groundwater-to-surface
       water pathway and implications for the wildlife food chain,  crop
       uptake,  and bioaccumulation by edible aquatic organisms.

    The CHAIN model predicts constant infiltration over time.  This steady-
state approach tends to overpredict velocity,  underpredict travel time and
degradation, and overpredict contaminant concentration.  PRZM uses a curve-
number approach derived by the U.S.  Department of Agriculture's Soil
Conservation Service to distribute daily rainfall into runoff and
infiltration.  Infiltrating water cascades downward to successively deeper
layers as the soil water content of each layer exceeds field capacity.  PRZM's
dynamic approach allows consideration of pulse loads and prediction of peak
events and estimates time-varying mass emission or concentration profiles.

    The Agency's steady-state approach was designed to predict long-term
effects over the MEI's 70-yr lifespan.  Short-term fluctuations in pollutant
concentrations predicted by PRZM average out in such an analysis.  The steady-
state CHAIN model is adequate for the slowly degrading chemicals currently
being regulated for sludge disposal in landfills.  In the future, if more
rapidly degrading chemicals are added to the regulation,  the effects of short-
term fluctuations will be evaluated using a dynamic modeling approach such as
PRZM.

    The Agency agreed with the SAB recommendation that anaerobic conditions
should be assumed for the unsaturated zone below a sewage sludge landfill.
The dissolved organics that leach out of these landfills are expected to
produce an anaerobic environment.  The current version of the Agency's
landfill model includes anaerobic biodegradation rates and hydrolysis rates
for the regulated pollutants.

    The SAB also suggested that the Agency's landfill model simulate the
effect of liners on leachate quality and quantity.  The Agency decided against
this suggestion because liners are not being required in this regulation and
generally are not in use at sewage sludge monofills.  The model is based on
                                    2-26

-------
the conservative assumption that no liner is present, so that the calculations
will yield the most protective maximum allowable sludge concentrations.

    The Agency decided to postpone action on the SAB recommendation that the
model be expanded to consider the groundwater-to-surface-water pathway   The
Agency is convinced that the existing groundwater and vapor analysis accounts
for the most likely pathways of human contamination.  The Agency is requesting
public comment on the need to consider the groundwater-to-surface-water link
and its effects on human and ecosystem health.  Based on public comments, the
Agency will consider adding this surface-water pathway to the model.
                                     2-27

-------
                               SECTION THREE
                     DATA BASE FOR THE RISK MODEL
    As discussed in Section 2, the SLUDGEMAN model, along with its associated
submodels,  is used to calculate the pollutant concentrations  in sludge  that
will allow a particular risk level (specified as  a set of human health  or
environmental impact criteria) to be met.   Before the  SLUDGEMAN model can  be
run, however, a number of parameters must  be specified.   These parameters
define (1)  a model sludge type; (2) groundwater conditions,  saturated and
unsaturated zone conditions,  and landfill  surface dimensions  for the
hypothetical site;  and (3) chemical-specific factors,  such as sludge
contaminant concentrations.   This section  presents the values assigned  to  each
parameter and discusses the basis for the  choice  of each value.   Table  3-1
presents a summary of all the parameters to be defined with their assigned
values (except for the chemical-specific parameters, which are too numerous to
list here)    Some of these values are input by the user;  others are "hard-
wired" into the program.
3.1 MODEL SLUDGE PARAMETERS

    The model requires that a specific sludge type be defined.  Sludges are
defined primarily by their water or solids content,  their storage  capacity,
their density,  and their specific gravity.  The  parameters that define  the
model sludge follow.
    3.1.1  Sludge Moisture Content

    The value selected to represent the model sludge moisture content is 0.8
kilograms (kg)/kg, which indicates a sludge with a solids content of 20%.
                                      3-1

-------
   TABLE 3-1.  Summary of Model Parameters and Assigned Values
Parameter
                                                      Value
Sludge Parameters
Sludge moisture content
Sludge storage capacity
Sludge density
Specific gravity (solids)

General Hvdrologic Parameters
Net recharge
Depth to ground water (Class I; other)
Aquifer thickness
Ground water pH
Ground water Eh
Saturated soil hydraulic conductivity

Unsaturated Zone Parameters
Unsaturated soil type
Bulk density in saturated zone
Effective porosity in saturated zone
Saturated zone hydraulic conductivity
Hydraulic gradient in saturated zone

Surface Parameters
Landfill site geometry
Distance to property boundary
Surface wind velocity
Air temperature
Air-filled porosity of cover soil
Total porosity of cover soil
Cover thickness (active and final)

Chemical-specific Parameters
Concentrations of sludge contaminants in sludge
Concentrations of contaminants in sludge leachate
Distribution coefficient
Saturated and Unsaturated zone decay rate
Background concentrations of contaminants
Health effects levels
Molecular weight
Henry's law constants
0.8 kg/kg
0.90 kg/kg
1,025 kg/m3
1.125
0.5 m/yr
Om; 1m
15 m
6 su
500 mv
10,000 mg/yr
Sand
2,380 kg/m3
0.1 m3/m3
2,000 m/yr
0.005 m/m
100 m x 100 m x
3.46 m
Cell length = 8 m
150 m
1 m/sec
15° C
0.1 m3/m3
0.4 m3/m3
0.3 m; 1 m
See
See
See
See
See
See
See
See
Sec.
Sec.
Sec.
Sec.
Sec .
Sec.
Sec .
Sec.
3,
3.
3.
3,
3
3
3
3
,6,
6.
,6.
.6
.6
.6
.6
.6
.1
.2
.3
.4
.5
.6
.7
.8
                               3-2

-------
This value was selected because a solids content of 20% is required  for
sludges codisposed in municipal landfills and because most types of  sludge
landfills commonly take sludges with solids contents of about  20%    Table 3-2
presents typical solids contents of sludges disposed in a number of  different
types of monofills.
     3.1.2  Sludge Storage Capacity

     The storage capacity  for water in sludge is  the moisture content of the
sludge when it  has been allowed to  drain completely   It  is  defined  as  the
"dry" water content per square  meter  (m2)  of the  sludge under normal
atmospheric conditions.

     For the  risk model, the storage capacity was set equal to the typical
moisture content  of gravity-thickened  sludge,  that  is,  0.90  kg/kg.   The
selection of  this value is  conservative because  it  represents  a high storage
capacity and, thus, a moister sludge.  In moister sludges, more water is
available to  move through the overburden into  the ground  water, and  pollutants
are  more likely to reach ground water  faster.  Thus,  the  health and
environmental risks associated  with sludges  having  a high storage  capacity  are
greater than  those for sludges  with a  low storage capacity.
     3.1.3  Sludge Density

     Density is  defined as  the mass of a substance per unit volume.   The value
selected for sludge density  in  the  model  is  1,025  kg/cubic  meter  (m3),  which
represents  the  sludge's effective  density.   For  sludges,  the  effective  density
is a more appropriate  measure  of density  than  density as  defined  above.   The
effective density takes into  consideration the physical state (particle size,
                                      3-3

-------
         TABLE 3-2.   Typical Sludge Solids Content by Landfill Type
      Type of Landfill                Percentage  of Sludge Solids (%)
       Narrow trench                           15-28
       Wide trench                               20
       Area fill mound                           20
       Area fill layer                           15
       Diked containment                         20
Source:   EPA,  1978.
                                  3-4

-------
amount of bound water, degree of flocculation, etc.) and the chemical
composition of the discrete sludge particle as it exists in a sludge mixture.

    As the  solids  content  of  a  sludge  increases, the density is  even better
described as a bulk density.  A bulk density calculation considers the entire
sludge mixture when figuring density.  This type of calculation  is not
required to determine the  density of a sludge with a 20% solids  content.
     3.1.4  Specific Gravity

     The density of the  sludge  is  used to  calculate  its  specific  gravity,
which is defined  as the ratio  of  the  density of a substance to the density of
a  standard  substance.  The standard substance used to calculate  the specific
gravity of  the  modeled sludge  is  water, which has a density of 1,000
grams/liter (g/L)  under standard  conditions of temperature and pressure.
Sludge with low solids content has a  density similar to that of water, so its
specific gravity  is close to one.  As  the sludge solids content  increases, the
density of  the  sludge increases because water is displaced with  solid
materials that  have a higher density  than water.  The density could decrease,
however, if the water is displaced by  solid material with a relatively lower
particle density  than water.

     The specific gravity of  a  sludge  can  be readily determined by  simple
procedures  such as those presented in  Standard Methods  for the Examination of
Water and Wastewater (APHA, 1971).  This method involves determining the
weight of a given volume of sludge compared to the weight of an  equal volume
of distilled water.  As noted  in  Standard Methods, free- and nonfree-flowing
sludges have different densities; free-flowing sludges  have effective
densities and nonfree-flowing  sludges  have bulk densities.  These different
types of densities must be taken  into  account when sludge is analyzed.

     The specific  gravity of  sludge can vary widely  depending on  the  state of
the sludge  (e.g., whether it has  been  settled, thickened, dewatered, dried,

                                      3-5

-------
 etc.).   Therefore,  the  conditions under which a sludge was  sampled should
 always  accompany  any  statement about its specific gravity,  and  the analytical
 characterization  methods used to determine the solids content should be
 specified.

     Measuring sludge  density is  not  a  simple  task;  the specific gravity of
 sludge  is usually easier to  measure than its density.  Rather than measuring
 density to calculate  specific gravity,  the models can measure the  specific
 gravity of the  sludge solids to derive the specific gravity of  the whole
 sludge,  which  is  the  reciprocal of the sludge density.  The following equation
 illustrates  this  calculation (Eckenfelder and Santhanam,  1981).
             rwn   +    rwn    =  j_
             SGwa[er      SG^       SG3
where  SG    = sludge specific gravity
       WP    = weight percentage
     1/SGS    = sludge density
In the case of the sludge being defined here,  which has a 20% solids content
a specific gravity of 1.139 for the sludge solids (chosen to represent a
typical value for the modeled sludge)  produces the following:
        0.8 +  0.2   =    1
        1.0   1.139     1.025
[2]
This calculation shows the derivation of the 1.025 kg/nr density  defined  in
Section 3.1.3.                                  /
                                     3-6

-------
3.2  GENERAL HYDROLOGIC PARAMETERS

    The model requires a number of inputs that define the general hydrologic
conditions of the hypothetical site.  These inputs include net recharge, depth
to ground water, aquifer thickness, and groundwater pH (relative hydrogen ion
concentration) and Eh  (oxidation-reduction potential)   These parameters are
discussed in the following sections, and the values selected for use in the
model  are presented.
    3.2.1  Net Recharge

    The primary source of ground water is precipitation,  which infiltrates
 through the  ground surface and percolates to the water table.  Net recharge is
 the  amount of water per unit of land that penetrates the ground surface and
 reaches the  water table.  Consequently, recharge water is available to
 transport a  contaminant vertically to the water table and horizontally within
 the  aquifer.  The recharge rate, which is the amount of recharge per year
 (yr),  controls  the quantity of water available for dispersion and dilution of
 contaminants.   Recharge is thus a principal vehicle for leaching and
 transporting solid or  liquid contaminants to the water table.  The greater the
 recharge  rate,  the greater the potential for pollution, up to the point at
 which  the amount of recharge is large enough to dilute the contaminant.  At
 this point,  the pollution potential ceases to increase and may actually
 decrease  (EPA,  1985b).

    For modeling purposes,  the recharge value was set to the highest rate of
 net  infiltration known to occur, 0.5 m/yr, based on information from the
 Hazardous Waste Management System Land Disposal Restrictions Regulation (51 FR
 1602,  January 14, 1986)   The highest rate of net infiltration was chosen as
 most conservative because, as discussed previously, pollutants are more likely
 to reach  ground water  and travel at a faster rate when the rate of recharge is
 greater.
                                      3-7

-------
    3.2.2  Depth to Ground Water

    The depth to ground water is generally defined as the depth from the land
surface  (or the lowest point of the landfill) to the water table.  The water
table  is  the subsurface  interface between the unsaturated zone (where the pore
spaces are filled with water and air) and the saturated zone beneath  (where
all the pore spaces are  filled with water) ; it may be present in any  type of
media  and may be either permanent or seasonal.  Most saturated zones  are
termed aquifers unless they lack the permeability to yield sufficient water.
Only true aquifers are considered when computing depth to ground water.

    The depth to ground water is important in evaluating the likelihood that
pollutants moving through the unsaturated soil will reach the ground  water.
It also determines the distance that a contaminant must travel before reaching
the aquifer, and it may help to determine the amount of time during which the
contaminant maintains contact with the surrounding media.  These factors
influence the amount of  attenuation that may occur as the pollutants  are
transported.  Attenuation processes lessen the amounts or deleterious effects
of contaminants.  The factors that affect attenuation are the physical and
chemical  processes and properties that include density; solubility, sorption,
biodegradation, oxidation-reduction, dilution, hydrolysis, dispersion,
viscosity, mechanical filtration, ion exchange, volatilization, and buffering
or neutralization.   As depth to ground water increases, the degree of
attenuation tends to increase,  leading to a decrease in pollution potential.

    To  identify a suitable value for depth to ground water in the model,  eight
landfills were monitored throughout the United States, and depths to  the
ground water below them were compiled (EPA, 1977b).  A typical depth  to ground
water of  5 m was observed among these landfills.  A value of 0 m for  Class I
ground waters was chosen to  model a worst-case depth to ground water.  This
conservative value,  which represents a situation where the bottom of  the
landfill  is occasionally or  regularly below the water table, is used  to
provide the maximum protection to these most sensitive ground waters  when
                                     3-8

-------
determining allowable sludge contaminant concentrations.  The 1-m value is
used to represent the depth to all other ground waters, since this depth  is
believed to be the minimum distance necessary to provide adequate protection
to human health and the environment while reflecting a reasonable worst-case
scenario.
    3.23 Aquifer Thickness

    A value of 15 m was chosen as a reasonable aquifer thickness for three
reasons.  First, a very small thickness  (under 3 m) will have influences  in
the model beyond simple mixing and dilution.  In aquifers of this size, the
leachate could constitute a  large portion of the mixture, thereby nullifying
one of  the basic assumptions of  the groundwater model, i.e., that leachate
makes up a small portion of  the  total aquifer.  Second, mixing does not
increase with depth beyond about 15 m.   Finally, the sensitivity analysis
showed  that when mixing beyond 15 m was  modeled, no significant (i.e., order
of magnitude) difference in  the  allowable contaminant levels in sludge were
calculated.   (See Section 4  for  results  and discussion of sensitivity
analyses.)
    3.2.4  Groundwater pH

    The pH of a solution denotes the negative log of the hydrogen ion
concentration of that solution.  In general, the lower the pH, the greater the
solubility of metals.  The lowest pH examined in the MINTEQ simulations, 6
standard units  (su), is therefore chosen as the most conservative value.   (See
discussion of MINTEQ in Section 2.)
                                      3-9

-------
    3.2.5 Groundwater Eh
    The measure of oxidation-reduction potential, Eh,  indicates  the  potential
of a solution to transfer electrons from the oxidant to the reductant.  The
higher the Eh value, the more readily metals migrate.   The highest value of Eh
examined in the MINTEQ simulations, 500  millivolts  (mv),  was chosen as the
most conservative value.
3.3 UNSATURATED ZONE PARAMETERS

    The unsaturated zone is  the  zone where the soil pore spaces  are  filled
with water and air, distinguishing this zone from the saturated zone,  where
pore spaces are filled only with water.  A number of  soil  types and conditions
must be defined for the unsaturated zone as  part of  the transport modeling.
These parameters are defined in the following sections.
    3.3.1 Unsaturated Zone Soil Type

    Soil type in the unsaturated  zone has a significant  impact  on  the  amount
of recharge that can infiltrate into the ground and hence on the ability of a
contaminant to move vertically into the aquifer.   Additionally, the
attenuation processes of filtration, biodegradation,  sorption,  and
volitilization that can take place in the unsaturated zone depend on the soil
type.  The quantity of organic material (F^)  present in the soil may also be
an important factor for attenuation.  In general,  the pollution potential of  a
soil is largely affected by the type of clay  present, the shrink/swell
potential of that clay,  and the grain size  of the  soil;  that is, the less the
clay shrinks and swells and the smaller the grain  size of the soil, the less
the pollution potential associated with the soil.   Soil types in the
unsaturated zone in order of increasing pollution  potential are
                                     3-10

-------
(1)  nonshrinking clay, (2) clay loam, (3) silty loam, (4) loam, (5) sandy
loam,  (6) shrinking clay, (7) sand, (8)  gravel, and (9)  thin or absent soil
(EPA,  1985a).

    Sand has been selected as the  modeled soil type for  two  reasons.   First,
Gerritse et al. (1982) used sand as a soil type when measuring the
partitioning of elements between soil and a sewage sludge solution phase.
These partitioning measurements (i.e., Kj values,  or  distribution
coefficients)  are considered the best available for the analysis of metal
transport from landfilled sludge.   The same soil type is also used for
nonmetals for convenience and consistency of analysis.  Second, sand is one of
the soil types with the highest pollution potential and, as such,  serves as a
reasonable worst-case soil.
    33.2  Unsaturated Zone Thickness

    The unsaturated zone thickness is important in determining how long it
takes contaminants to reach the aquifer, i.e., contaminant travel time.  The
longer  the travel time, the greater the chance that attenuation processes may
act on  the contaminants.  The degree of attenuation that occurs depends on
(1) the length of time  that the contaminant is in contact with the material
through which it passes; (2) the grain size of the material through which it
passes; (3) the physical and chemical characteristics of the material through
which it passes; and (4) the distance that the contaminant has traveled.  For
most contaminants, a greater degree of attenuation is associated with longer
travel times, greater media surface areas, and greater contaminant travel
distances.  In general, therefore, as the thickness of the unsaturated zone
decreases, the pollution potential increases.

    The thickness  of the unsaturated zone over Class  I ground water has thus
been chosen as 0 m, a conservative but reasonable worst-case scenario for
sensitive ground water.  A value of 1 m has been chosen to represent the case
of a landfill over other groundwater classes.  This value is considered to
                                      3-11

-------
represent a reasonable worst-case scenario for these less-sensitive
groundwater types.

    Only one unsaturated layer is assumed in these reasonable worst-case
scenarios.  Therefore, the thickness of the layer and the depth  to ground
water are the same and vary only with the underlying groundwater
classification.
    3.3.3  Slope of the Soil Moisture Retention Curve

    The slope of the soil moisture retention curve is also called the slope  of
 the curve plotting matric potential versus moisture content.   The matric
 potential is a pressure potential that arises from the interaction  of water
 with the matrix of solid particles in which it is embedded.   It  is  also
 associated with water retention by the soil matrix.  Water added to soil is
 subject to forces of capillary and surface adsorption that vary  with water
 content (Marshall and Holmes, 1979).

    The value of the slope of the soil moisture retention curve has been set
 at 4.  This value is the typical value for sand, as can be seen  in  Table 3-3,
 which presents a range of slopes for the soil moisture retention curve.
    3.3.4 Effective Porosity of the Unsaturated Zone

    Porosity is  the ratio of the  void volume of a given soil or rock mass  to
the total volume of that mass.  If the total volume is represented by  VT,  the
volume of the solids by Vs,  and the volume  of the voids by Vv,  then the
porosity, n, is  defined as  VV/VT.  It is  usually  reported as a decimal
fraction or as a percentage and ranges from 0  (no pore space)  to  1 (no solid)
(Freeze and Cherry, 1979).   The porosity of a uniform porous medium is largely
  function of particle size.  For soil types with small particle  sizes such as
a
                                     3-12

-------
TABLE 3-3.   Typical Values for the Slope of the
             Soil Moisture Retention Curve by Soil Type
    Soil Texture                  Slope
    Clay                           11.7
    Silty clay                      9.9
    Silty clay loam                 7.5
    Clay loam                       8.5
    Sandy clay loam                 7.5
    Sandy silt loam                 5 4
    Silty loam                      4.8
    Sandy loam                      6.3
    Loamy sand                      5.6
    Sand                            4
  Source:  Hall et al. (1977).
                        3-13

-------
 clay,  porosity  increases  to  a  maximum  of  around  50%.   Porosities of coarser
 media  like  gravel  decrease to  a minimum of  around 30%.   These measured ranges
 of  porosities suggest  a strong correlation  with  mean  particle diameter.

    The term effective porosity refers to the amount of  interconnected pore
 space  available  for  fluid flow and  is  also  expressed  as  a ratio of voids to
 total  volume.  The effective porosity  is  identical  to  porosity for many
 unconsolidated porous  media  and for many  consolidated rocks  (Todd, 1980) .

    The porosity value representative of coarse and medium sand is 0.39 m/m .
 For fine  sand, this  value is 0.43 m3/m3  (Todd,  1980).   The lower value  of 0.39
 m3/m3 was  chosen  both as most representative of the  modeled soil type and as
 most conservative.
    3.3.5  Bulk Density in the Unsaturated Zone

    The bulk density of soil is defined as the mass of dry soil divided by  its
 total  (or bulk) volume.  Bulk density directly influences  the  retardation of
 solutes and is related  to soil structure.   In general, as  soils become more
 compact, their bulk density increases.  This relationship  produces  a
 dependency between porosity and bulk density.  Freeze and  Cherry  (1979)  note
 that the porosity is equal to one minus the ratio of bulk  density to particle-
 size density   The particle density of soil materials varies over a very
 narrow range and can be fixed at a value of 2.65 g/cubic centimeter (cm3)
 (Freeze and Cherry, 1979)   If particle density is assumed equal  to 2.65
 g/cm3,  the bulk density  can be  expressed  in terms  of  porosity as follows:


        Pb  =  2.65 (1 - 9)                                                (3)
where  Pb   =  bulk  density,  g/cm3
       9   =  porosity
                                     3-14

-------
    For modeling purposes, bulk density values were obtained from the
literature; the value chosen for the unsaturated zone,  1,400 kg/m3, is a
common value for sand.
    33.6  Saturated Soil Hydraulic Conductivity

    Unsaturated soil becomes saturated as water or leachate passes through it
to the saturated zone below.  Thus the hydraulic conductivity of the
unsaturated zone must be estimated for those  times when this zone becomes
saturated.  Hydraulic conductivity refers to  the ability of the soil or
aquifer materials to transmit water, which in turn controls the rate at which
ground water will flow through soil or an aquifer under a given hydraulic
gradient.  The rate at which ground water flows also controls the rate at
which a contaminant will move away from the point at which it enters the soil
or aquifer.  Hydraulic conductivity is governed by the amount and
interconnection of void spaces in the soil or aquifer.  These voids may occur
as a consequence of intergranular porosity, fracturing, or bedding planes.   In
general, high hydraulic conductivities are associated with high pollution
potential.

     Saturated  soil hydraulic conductivity  (K^)  is  estimated from the
representative values for saturated hydraulic conductivity in Freeze and
Cherry (1979).   The value chosen to represent the model landfill site is
10,000 m/yr, which is set at the high end of the hydraulic conductivity scale
for clean sand.
3.4 SATURATED ZONE PARAMETERS

    The  saturated  zone, with  its water-filled pore spaces, is in most cases
considered an aquifer.  A number of parameters must be defined for the
saturated zone when modeling pollutant transport.  These parameters,  which
                                     3-15

-------
 include soil type,  soil  hydraulic  conductivity,  effective porosity, hydraulic
 gradient,  zone hydraulic conductivity,  and bulk  density,  are discussed below.
     3.4.1  Saturated Zone Soil Type

     In the saturated zone,  the soil type exerts the major control over the
 route  and path length that  a  contaminant must  follow.   The path length is an
 important control  (along  with hydraulic  conductivity and gradient)  in
 determining the time  available for  attenuation processes such as sorption,
 reactivity,  and dispersion.   It is  also  important  in determining the amount of
 effective surface  area of the materials  contacted  by a  contaminant  in the
 aquifer.   In general,  larger  grain  sizes and more  numerous fractures or
 openings  within the aquifer are associated with higher  permeabilities and
 lower  attenuation  capacity and,  consequently,  a greater pollution potential.
 Soil types  in the  saturated zone in order of increasing pollution potential
 are:   (1) massive  shale;  (2)  metamorphic/igneous;  (3) weathered
 metamorphic/igneous;  (4)  bedded sandstone, limestone, and shale;  (5) massive
 sandstone;  (6)  massive  limestone; (7) sand and gravel;  (8)  basalt;  and
 (9) Karst limestone (EPA, 1985a).  For the same reasons as discussed in
 Section 3.3.1,  sand has been  chosen to represent a reasonable worst-case  soil
 type.
    3.4.2  Effective Porosity in the Saturated Zone

    Effective porosities for general hydrogeologic  classifications are
presented in Table 3-4.  The value of 0.1 m3/m3 has been chosen  to  represent
the effective porosity in the saturated zone.  See the discussion  of effective
porosity in Section 3.3.4 for additional information on this  parameter.
                                     3-16

-------
      TABLE 3-4.   Effective Porosities for General
                   Hydrogeologic Classifications
                                       Effective
Hydrogeologic Classification           Porosity


Fractured crystalline silicates        0.01

Fractured and solutioned carbonates    0.10

Porous carbonates                      0.10

Porous silicates                       0.01

Porous unconsolidated silicates        0.16a

Fractured shale                        0.01


aAverage  value.

Source:  Shafer et al.  (1984)
                         3-17

-------
    3.43  Hydraulic Gradient in the Saturated Zone

    The hydraulic  gradient  is,  in  general, a  function of the local
topography, the groundwater recharge volumes and locations,  and the influence
of withdrawals (e.g., well fields).  It is also very  likely  to  be  indirectly
related to porous media properties.  Rarely are large  gradients associated
with very high conductivities.  No functional relationship exists,  however,  to
express this association.

    The hydraulic  gradient value selected for use  in  the model is  0.005 m/m
and is based on an  average value of a number of ground waters  surveyed for the
Hazardous Waste Management System Land Disposal Restrictions Regulation (51  FR
1602, January 14, 1986).
     3.4.4  Bulk Density in the Saturated Zone

     Bulk  density values  are obtained from the  literature  and the value chosen
for  the saturated zone, 2,390 kg/m3,  is  a  common value for sand.  More
information on the derivation of bulk density is presented  in  Section 3.3.5.
    3.4.5  Saturated Zone Hydraulic Conductivity

    The saturated zone hydraulic conductivity reflects  the ease with which
water is transported through porous media.  For any given  fluid,  the hydraulic
conductivity is a function of properties such as particle  size,  grain shape,
connectivity,  and tortuosity, which affect the porosity of the  medium.
Individual,  site-specific measurements for hydraulic conductivity are usually
difficult to make,  and the spatial variability of "point"  measurements is the
subject of much current research.
                                     3-18

-------
    In addition  to  porosity,  saturated  zone  conductivity  is  related to  the
velocity of ground water and  the hydraulic gradient.  The velocity  of ground
water is a major determinant  of solute  transport in subsurface systems; in
uniform,  porous media, it is  the dominant factor.  Groundwater flow velocities
vary widely.  Mackay et al. (1985) report that velocities typically range
between 1 to 100 m/yr.  These ranges apply to typical ''natural gradient"
conditions, but higher velocities can exist under both induced situations
(e.g., well-field drawdown) and extreme natural situations.  For example,
velocities in excess of 9,000 m/yr have been reported for a  glacial outwash
material (Guven et  al., 1984).

    Velocities  are  related  to soil properties and  other site-specific  factors
through Darcy's  law.  When  Darcy's law  and assumptions of steady flow in
uniform, saturated  media are  used, the  following expression  for average pore
velocity V is produced:

       V   =     Ks x  S                                            (4)
                     6
where  V = velocity of ground water, m/yr
       K, =  saturated zone hydraulic  conductivity,  m/yr
       S = hydraulic gradient
       8 = porosity

This equation can be rearranged as K, =  9V/S  to  derive  the hydraulic
conductivity.  The  saturated  zone hydraulic conductivity was calculated based
on a worst-case  groundwater velocity of 100 m/yr, which was  determined from
the sensitivity  analysis discussed in Section 4.  Given a velocity, V, of 100
m/yr, a hydraulic gradient  of 0.005  (see 3.4.4), and a saturated zone
effective porosity  of  0.1 m3/m3 (see  3.4.3),  the  saturated  zone  hydraulic
conductivity for the model  is calculated to be 2,000 m/yr.
                                      3-19

-------
3.5  SURFACE PARAMETERS

    Several other miscellaneous parameters must also be defined for  the
model: the landfill site geometry,  the distance to site boundaries, the
surface wind velocity, the air temperature,  the porosities of cover soil, and
the cover thickness.  These parameters and assigned values are discussed
below.
     3.5.1  Landfill Site Geometry

     Table  3-5 presents the geometry used to model the landfill site.  The
 landfill width and length represent the square root of the average area of
 landfills examined for the Hazardous Waste Management System Land Disposal
 Restrictions Regulation (51 FR 1602,  January 14,  1986).   The fill height and
 cell length are representative values for landfills.
    3.5.2  Distance to the Property Boundary

    Within the landfill property, the owner/operator can exercise control to
ensure that there will be no exposure to pollutants at concentrations greater
than the health effects levels.   This area is thus known as the area of
effective control.   The area of effective control is considered to end at the
point of potential exposure, which for Class II aquifer analysis is defined as
the property boundary.    The modeled pollutant concentrations do not exceed
the health effects level at this  point when the model has calculated the
maximum allowable contaminant concentrations in the sludge.

    To determine an appropriate distance that would represent the point of
potential human exposure,  the Agency surveyed 163 Part B hazardous waste land
disposal permit applications available to EPA as of October 1984.  Based on
                                     3-20

-------
      TABLE 3-5.  Landfill Site Geometry
Parameter                   Value  (m)







Landfill width                100




Landfill length               100




Cell length                     8




Fill height                     3.46
                    3-21

-------
this information, the Agency believes that 150 m is a  reasonable,  conservative
estimate of the point of effective potential human exposure.
    3.53  Surface Wind Velocity

    A value  of  1 m/sec has been  selected  to  represent a reasonable value for
surface wind velocity.  For site-specific modeling, more  exact calculations
may be made with values obtained from local weather stations  or measured on
site (Tucker and Preston, 1984).
    3.5.4  Air Temperature

    An air  temperature  of  15°C has been selected as a reasonable  value.   The
value could be measured on site or taken from local weather  stations for a
more exact calculation when site-specific modeling is performed.
    3.5.5  Air-filled Porosity of Cover Soil

    It is assumed  that cover soils will be  drained to  field capacity, which
is the water content found when a thoroughly wetted soil has  drained for about
2 days.   Under this assumption, the air-filled porosity is  set equal to the
effective porosity, or 0.1 m3/m3.
    3.5.6  Total Porosity of Cover Soil

    A value of 0.4 m3/m3 has been chosen as  representative of a soil cover of
sand,  a worst-case scenario.
                                     3-22

-------
    3.5.7  Cover Thickness

    The thickness of  the active cover has been set at 0.3 m; the thickness of
the final cover has been set at 1 m.  These values are minimal values and are
used to represent worst-case conditions.
3.6 CHEMICAL-SPECIFIC PARAMETERS

    A number  of  chemical-specific  factors must be quantified before being
input to the model.  These factors include the concentration of contaminants
in the sludge by dry weight basis; the concentration of contaminants in the
leachate; the distribution coefficient; the saturated and unsaturated zone
decay rate; the background concentration of contaminants, and other factors.
The chemical-specific parameters and the values assigned to them are discussed
below.
     3.6.1  Concentrations of Contaminants in Sludge

     The  concentrations  of contaminants  in  the modeled  sludge are presented  in
Table 3-6.  In many cases, the values were taken from 95th percentile values
obtained from a survey of  40 publicly owned treatment works (EPA, 1982)   The
values used for chlordane, lindane, DDT/DDD/DDE, trichloro-ethylene,  and
toxaphene, however, were the maximum values reported.  Other values were
derived as noted in the table.  These values were used to begin the Iterative
runs as a first approximation (see Section 2)
    3.6.2  Concentrations of Contaminants in Sludge Leachate

    The concentrations  of contaminants  in  the modeled  sludge  leachate  are
presented in Table 3-7   Most of these values were derived using the modeled
                                    3-23

-------
        TABLE 3-6.   Concentrations of Contaminants in Sludge (dry weight)
     Parameter                               Concentration  (mg/kg)
      Arsenic                                       2°'75a
      Cadmium                                       88.133
      Copper                                      5600
      Lead                                        1070
      Mercury                                        5.85
      Nickel                                       920
      Benzene                                        6.6
      Benzo(a)pyrene                                 1.935
      Bis(2-ethylhexyl)phthalate                   459
      Chlordane                                     12
      DDT/DDD/DDE                                    0.930
      Dimethylnitrosamine                            0.272
      Lindane                                        0.220
      Polychlorinated biphenyls                      2.90
      Trichloroethylene                             17.85
      Toxaphene                                     10.8
aThe value was obtained by averaging the maximum values reported by a number
 of surveys.

bThe value was the mean value reported in EPA  (1982) .


Source:   EPA (1982),  except  as  noted.
                                     3-24

-------
    TABLE 3-7.   Concentrations of Contaminants in Sludge Leachate
Parameter                            Concentration (mg/L)
Arsenic                                    1 a
Cadmium                                    0.2b
Copper                                    37 b
Lead                                      10 b
Mercury                                    0.69C
Nickel                                     3 4d
Benzene                                    0.12
Benzo(a)pyrene                             0.000006
Bis(2-ethylhexyl)phthalate                25 a
Chlordane                                  0.00014
DDT/DDD/DDE                                0.01e
Dimethylnitrosamine                        0.014
Lindane                                    0.00039
Polychlorinated biphenyls                  0.0000018
Trichloroethylene                          0.022
Toxaphene                                  0.15
"The value is based on an estimated liquid concentration that
 requires at least one year to deplete the mass of the leachate in
 the sludge.

'"The value was the maximum reported for leachate from a
 sludge monofill (EPA, 1978).

cThe value was recommended by Betsy Southerland (1987)

dThe value was the maximum effluent reported for municipal
 wastewaters. (Earth et al.,  1965)

eThe value was the maximum effluent value reported (EPA,
 1978)


Source:  Calculated from Koc and the values in Table 3-6, except
         as noted.
                         3-25

-------
sludge concentrations in Table 3-6 and the organic carbon content of the soil
(K.J "at 5% total solids and 50% organic solids.  The sources  of  other values
are as noted in the table.  These values were used to begin the  iterative runs
as a first approximation.
    3.6.3  Distribution Coefficient

    Contaminant  transport  in  soil  systems  is  directly  related to
contaminant/soil interactions.  The affinity  that soil particles  have for
contaminants may result from  ion exchange on  charged sites or  adsorption due
to surface forces.  When that capacity is exceeded, soluble contaminants will
move through the soil at the  same velocity as the bulk leachate.   The affinity
between a soil and a contaminant, and therefore a soil's capacity to  hold a
contaminant, is characterized by the distribution coefficient  K,-,.
Representative K
-------
          TABLE 3-8.   Distribution Coefficients, K,
Parameter                         Coefficient  (L/kg)
                                      Inorganic
Arsenic
Cadmium
Copper
Lead
Mercury
Nickel
5.
14.
41.
234
322
12.
.86
,9
.9
2
                                      Organic
 Benzene                                 0.0074
 Benzo(a)pyrene                         550
 Bis(2-ethylhexyl)phthalate          200000
 Chlordane                               17
 DDT/DDD/DDE                            500
 Dimethylnitrosamine                     0  000004
 Lindane                                 0.108
 Polychlorinated biphenyls               32
 Trichloroethylene                       0.0198
 Toxaphene                               0.06
 "Based on an f^ of 10"4 x KO,. (see text) .
                                  3-27

-------
where  K^ = organic carbon content of the soil
       fx = fraction of soil consisting of organic matter

     If the values  for K^ have not been determined experimentally,  equations
are available to estimate them from octanol-water partition coefficient  data,
known as K^ or solubility.

     For organic contaminants, Kj is  a function of organic content in soil.
The value of ICT* was selected for the fx values as  a typical value for sand.
It is assumed that subsoils in the aquifer will not contain organic matter
and, therefore, the Kj for  organics  in the  saturated zone is  set equal to
zero.
    3.6.4  Saturated and Unsaturated Zone Decay Rate

    Reductions in pollutant concentrations due to degradation processes  such
as hydrolysis and biochemical oxidation are characterized by a degradation
constant,  or decay rate,  which is related to the time required for the
contaminant concentration to be reduced to one-half its initial value.   (See
Section 2  for more details.)  The values used in the model to represent  the
saturated and unsaturated zone decay rates are presented in Table 3-9.
    3.6.5  Background Concentrations of Contaminants

    The background concentrations of contaminants in ground  water  were taken
from "Significance of Properties and Constituent's Reported  in Water Analysis'
(Hen,  1985)  and are presented in Table  3-10.   Where explicit values were  not
                                     3-28

-------
   TABLE 3-9.   Saturated and Unsaturated Zone Decay Rates
Parameter                               Decay Rate  (yr"1)
Arsenic                                    0
Cadmium                                    0
Copper                                     0
Lead                                       0
Mercury                                    0
Nickel                                     0
Benzene                                    0
Benzo(a)Pyrene                             0
Bis(2-ethylhexyl)phthalate                 0
Chlordane                                  8.43a
DDT/DDD/DDE                                0.904b
Dimethylnitrosamine                      607 . Oa
Lindane                                    8.43C
Polychlorinated biphenyls                  0
Trichloroethylene                          0.904d
Toxaphene                                  0
aThis value was obtained from EPA's Athens Environmental
 Research  Laboratory  (Kollig)

bThis value was taken from Wolf et al.  (1977)

°rhis value was taken from Raghu and MacRae (1966)

dThis value was taken from Kleopfer (1985)

Sources:   As noted  above.
                            3-29

-------
    TABLE 3-10.  Background Concentrations of Contaminants
Parameter                               Concentration (mg/L)
Arsenic                                       0.0004
Cadmium                                        0.001
Copper                                          0.01
Lead                                           0.001
Mercury                                       0.0003
Nickel                               .         0.0027
Benzene                                            0
Benzo(a)pyrene                                     0
Bis(2-ethylhexyl)phthalate                         0
Chlordane                                          0
DDT/DDD/DDE                                        0
Dimethylnitrosamine                                0
Lindane                                            0
Polychlorinated biphenyls                           0
Trichloroethylene                                  0
Toxaphene                                          0
                            3-30

-------
given, values were estimated from this source.  Since metals are ubiquitous,
they can be expected to be found naturally in ground waters.  Organics,
however, are not expected to be found in noncontaminated ground waters  and,
therefore, the background concentrations of organics were set to zero
    3.6.6  Health Effects Levels

    The health  effects level (HEL,  in mg/L)  is  defined as  a groundwater
concentration used to  evaluate the potential for adverse effects on human
health as a result of  sludge  landfilling.  The monofill pollutant  limits that
represent allowable contaminant concentrations in sludge to be monofilled,
which are presented in §503.43 of the  Sewage Sludge Technical Regulations,
were calculated  to result  in  groundwater concentrations below the  HEL  at the
point of compliance.   The  point of compliance is the property boundary for
Class II aquifer analysis, but is the  point at which leachate enters the
aquifer for Class I aquifer  analysis.   (See Section 2.3 for a definition of
these two types  of analyses.)

    The HEL values, presented in  Table 3-11, are  set equal to Maximum
Contaminant Levels (MCLs)  where they  are available.  Where KCLs are not
available, a HEL is calculated based  on Risk Reference Doses (RfDs) for
threshold-acting contaminants, (i.e.,  noncarcinogens)  or q:* values for
carcinogens.  The RfD  is a benchmark  dose for noncarcinogens derived from the
no-observed-adverse-effects  level (NOAEL) by applying  generally order-of-
magnitude uncertainty  factors  (UFs).   These UFs reflect various types  of data
used to estimate RfDs  and  an  additional modifying factor (MF), which is
derived based on professional judgment following review of  the contaminant's
entire data base.  In  general, the RfD is an estimate  (with uncertainty
spanning perhaps an order  of magnitude) of a daily exposure to the human
population (including  sensitive subgroups) that is very likely to  result in no
appreciable risk of health effects during a lifetime.  The RfD is
appropriately expressed in units of mg/kg-body weight  (bw)/day   The HEL was
calculated from  the RfD using the following equation:
                                      3-31

-------
             TABLE 3-11.   Health Effects Levels (mg/L)
Parameter
                                 Concentration  (mg/L)
Arsenic
Cadmium
Copper
Lead
Mercury
Nickel
Benzene
Benzo(a)pyrene
Bis(2 -ethylhexyl)phthalate
Chlordane
DDT/DDD/DDE
DimethyInitrosamine
Lindane
Polychlorinated biphenyls
Trichloroethylene
Toxaphene
0.05a
0.01"
1.3a
0.05a
0.0023
1.75"
0.005a
0.00003C
0.0248C
0. 00021°
0.00102°
o.oooor
0.004a
0.0000454°
0.005a
0.0005"
aThe  value  is  a  Maximum  Contaminant  Level  (MCL)  under the
 Safe Drinking Water Act (SDWA)

bThe  value  is  calculated from a risk reference dose (RfD)
 established by EPA's Office of Research and Development.

°The  value  is  calculated from a q:* value representing a
 maximum allowable dose for carcinogens at the 10"5 level.

Sources:  As noted above.
                              3-32

-------
           HEL =  RfD x BW                                       (6)
where  RfD =  reference  dose  (mg/kg/day)
       BW  =  human body weight  (kg)
       Iw  =  water ingestion rate (L/day)
The human body weight was set at 70 kg and the water ingestion  rate  at
2 L/day for adults, standard values used by EPA.

    For most carcinogenic chemicals, the linearized multistage  model  is
recommended for estimating human cancer potency  from animal  data  (49  FR
46298)   When epidemiological data are available, potency  is estimated based
on the observed relative risk in exposed versus  nonexposed individuals and  on
the magnitude of exposure.  Guidelines for using these procedures have been
presented in the Federal Register  (45 FR 79350-47353; 50 FR  46294-46301)  and
in each of a series of health assessment documents prepared  by  the Office of
Health and Environmental Assessment (OHEA).  The potency value, qf~  normally
used  in risk assessments, is the upper-bound estimate of the slope of the
dose-response curve in the low-dose range.  This value is  expressed  in terms
of risk per dose, where dose is expressed  in units of mg/kg/day  Thus,  qt* is
expressed in units of mg/kg/day"1   The HEL was calculated  from  q:* using  the
following equation:
            HEL  -  fRL x BW)/q.*                                   (7)
                        L
where  RL  = risk level
       BW  = human body weight (kg)
       Iw  = water ingestion rate L/day)
As in the RfD computation,  the human body weight was  set  at  70  kg  and  the
water ingestion rate at 2 L/day  for adults;  the risk  level  (qf*) was set
at 10'5.
                                     3-33

-------
    3.6.7 Molecular Weight

    The values presented in Table 3-12 are standard molecular weights  for
several contaminants of concern.  These weights are used in the vapor  loss
simulations and have been "hard-wired" into the model.
    3.6.8  Henry's Law Constants

    Henry's law constants are used to calculate the vapor loss of contaminants
from sludge and are "hard-wired" into the model.  Table 3-13 presents
constants for several contaminants of concern.  The values for benzo(a)pyrene
and bis(2-ethylhexyl)phthalate were calculated from vapor pressure and
solubility data that are maintained in the Henry's law database at Research
Triangle Park, using the procedures in Mackay and Shui (1981)   The vapor
pressure of bis(2-ethylhexyl)phthalate was calculated from boiling points  at
various pressures using Antoine's equation and the solubility data was
obtained from Verschueran (1983).   The value for chlordane was also obtained
from the database,  but was taken from Hwang (1982).  Values for DDT/DDE/DDD
and polychlorinated biphenyls (PCBs) were taken from Lyman et al  (1982)
Finally,  the value  for dimethyInitrosamine was taken from Dawson  et al.
(1980) .
                                     3-34

-------
   TABLE 3-12.  Standard Molecular Weights for Modeled Pollutants









Contaminant                                Molecular  Weight







Benzo(a)pyrene                                  252.32




Bis(2-ethylhexyl)phthalate                      391




Chlordane                                       410




DDT/DDE/DDD                                     354.5




DimethyInitrosamine                              74.08




Polychlorinated biphenyls                       300
                                   3-35

-------
       TABLE 3-13.  Henry's Law Constants for Selected Contaminants
Contaminant                                              Constant

Benzo(a)pyrene                                           0.000000017
Bis(2-ethylhexyl)phthalate                               0.004625
Chlordane                                                0.002
DDT/DDE/DDD                                              0.0017
Dimethylnitrosamine                                      0.02
Polychlorinated biphenyls                                 0.16
Sources:   As noted in text.
                                  3-36

-------
                               SECTION FOUR
                           SENSITIVITY ANALYSIS
    In developing the risk assessment methodology for  each  sludge  disposal
option,  the Agency selected or created mathematical  models  that would  predict
the average long-term human health and environmental effects  of continually
disposing of sludge in the soil and/or water.   The SLUDGEMAN  model was
developed to predict the maximum allowable  pollutant concentrations in sewage
sludge at a landfill site that would not detrimentally affect a Most Exposed
Individual (MEI).   The MEI was defined as a person who drinks 2 L  of ground
water per day from the site over a 70-yr lifespan.

    Existing disposal practices were extensively reviewed to  develop
reasonable worst-case values for the site characteristics used in  the  model.
Six sets of sensitivity analyses were performed on selected model  parameters.
The results of these analyses are discussed below and  are detailed in
Appendix B.

    The eight parameters evaluated for their effect on allowable sludge
concentrations are:

    •  Depth of the soil layer between the  landfill  and ground water
    •  Organic carbon fraction of that soil layer
    •  Distance to the point of compliance
    •  Groundwater velocity
    •  Aquifer thickness
    •  Net recharge rate
    •  Eh and pH conditions of the ground water
    •  Moisture content of the sludge
                                     4-1

-------
Adsorption and decay coefficients -- parameters specific to each chemical  --
were not evaluated in the sensitivity analyses.

    Initially, a base-line case scenario was run,  against which all subsequent
runs were compared.  The input parameters for the  baseline case are presented
in Table 4-1.

    The sensitivity analyses were performed by holding all parameters at their
baseline value or at other specific values,  except the parameter being
evaluated.  One parameter, distance to the property boundary,  was varied in
all the sensitivity analyses to determine the effect of this variable in
combination with all the other parameters of interest in these analyses.

    Because parameter sensitivity depends on the baseline conditions selected
and on the adsorption and decay coefficients assigned,  the analysis may not
give a generally applicable measure of sensitivity,  but rather a specific
measure applicable to the testing conditions.   It  is also important to note
that the validity of the sensitivity analysis hinges on the validity of the
model framework itself.
4.1 EFFECT OF SOIL DEPTH AND CARBON CONTENT

    The first set of sensitivity analyses  evaluated the effect on maximum
allowable sludge pollutant concentrations  of (1)  the depth of the soil layer
between the landfill and the ground  water  and (2)  the organic carbon content
of that soil layer.   The organic content of the soil was examined because it
influences the amount of organic pollutants that  will adsorb onto the soil,
thus not reaching the aquifer.   It does  not,  however,  affect metals leaching
to ground water   Depth to ground water  proved to  be an extremely sensitive
parameter for DDT,  lindane,  and bis(2-ethylhexyl)phthalate (BEHP),  as will be
discussed in the following sections.
                                     4-2

-------
     TABLE 4-1.  Input Parameters for the Baseline Case
Parameter
   Volume
Depth to ground water

Net recharge rate

Groundwater gradient

Hydraulic conductivity of
 saturated zone

Groundwater velocity

Aquifer mixing thickness

Eh and pH

Sludge moisture content

Sludge storage capacity

Sludge density

Width of landfill

Length of landfill

Height of fill

Aquifer width
    0 m

    0.5 m/yr

    0.005 m/m

2,000 m/yr


  100 m/yr

   15 m

 +500 mv/6.0

    0.80 kg/kg

    0.90 kg/kg

1,025 kg/m3

  100 m

  100 m

    3.46 m

1,000 m
                            4-3

-------
    4.1.1  Results for Class I Aquifers

    For Class I ground waters, as  described in Section 2, human health
criteria must be met at the point where the leachate first  enters  the aquifer.
Thus, the location of the landfill property boundary is not a  factor in the
analysis.  Table 4-2 presents the  results of the analyses for  Class  I
aquifers.  When a low soil organic carbon content of 0.0001 is assumed,  as
depth to ground water increases from 0 to 1 meter (m) , the  maximum allowable
concentrations increase for all the regulated pollutants by less than an order
of magnitude.  For soils with a high organic carbon content of 0.01,  as  depth
to ground water increases from 0 to 1m, the allowable sludge  concentrations
increase by two orders of magnitude for DDT and by three orders of magnitude
for lindane.  In other words, leachate from landfills with  sludges containing
the maximum allowable concentrations of these pollutants calculated  by these
sensitivity analyses would still meet the human health criteria at the point
where the leachate first enters the aquifer.

    For soils with an organic content of 0.0001, as the depth  to ground  water
increases to 5 m, allowable sludge concentrations for DDT increase by one
order of magnitude.   When an organic soil content of 0.01 m is assumed,  as
depth to ground water increases to 5 m, allowable sludge concentrations
increase by one order of magnitude for BEHP, two orders of  magnitude for DDT,
and three orders of magnitude for lindane.

    For soils with an organic content of 0.0001, as the depth  to ground  water
increases to 10 m,  the allowable sludge concentrations for  DDT and lindane
increase by one order of magnitude.  When an organic content of 0.01 is
assumed, the 10-m depth increases allowable sludge concentrations  by one order
of magnitude for BEHP and by three orders of magnitude for  DDT and lindane.
                                     4-4

-------
         TABLE 4-2.  Effect of Soil Depth and Organic Carbon Content
                      on Maximum Allowable Sludge Pollutant
                      Concentrations for Class I Aquifers
 Depth  of  Soil
Between Landfill
   and Aquifer
     Soil
   Organic
Carbon Content
  Pollutant
    Orders of
  Magnitude  of
   Increase in
Maximum Allowable
 Sludge  Pollutant
 Concentrations
  over Baseline
       1-m
       1-m
      0.0001
      0.01
All regulated
 pollutants

DDT
Lindane
   Less than 1
       5-m

       5-m
      0.0001

      0.01
DDT

BEHP
DDT
Lindane
      10-m
      0.0001
DDT
Lindane
      10-m
      0.01
BEHP
DDT
Lindane
                                     4-5

-------
4.1.2  Results for Class II Aquifers

    For Class II ground waters, human health criteria must be  met'after the
leachate mixes with the ground water and is transported  to the property
boundary of the landfill where water supply wells might  be constructed.   The
property boundary of the landfill is, therefore, an important  parameter in the
analysis of Class II aquifers.  The greater the distance from  the edge of the
waste management unit to the property boundary, the greater  the allowable
sludge concentrations because pollutants undergo more dilution and decay the
farther they travel in the aquifer.

    The sensitivity analyses of landfill model parameters were performed
assuming property boundary locations at 50 m, 150 m, 500 m,  and 1,000 m from
the landfill.  The results are given in Table 4-3.  For  the  50-,  150-,  and
500-m boundaries, a 0.0001 soil organic carbon content caused  an order-of-
magnitude increase in only one pollutant, DDT, at both the 1   and 5-m soil
depths, compared to the baseline of 0-m.  When a 0.01 soil organic  carbon
content was assumed, the maximum allowable pollutant concentrations of three
pollutants, DDT, BEHP, and lindane, increased significantly  at both the 1- and
5-m soil depths for all three boundaries.  Significant increases also occurred
for these three pollutants at the 10-m soil depth.

    The sensitivity analyses indicate that the 1,000-m property boundary
parameter was very insensitive to the depth of the intervening soil layer.
The 1,000-m distance is so far from -the landfill that allowable sludge
concentrations are controlled by dilution and transformation processes in the
aquifer rather than by processes in the soil layer under the landfill.   A 1-m-
deep soil layer caused no significant increase in maximum allowable pollutant
concentrations over reasonable worst-case sludge concentrations.   The 5- and
10-m-deep soil layers caused an order-of-magnitude increase  in just one
pollutant,  BEHP,  and that increase only occurred when the soil was  modeled
with a high fraction (0.01) of organic carbon content.
                                     4-6

-------
TABLE 4-3.  Effect of Soil Depth and Organic Carbon Content
             on Maximum Allowable Sludge Pollutant
             Concentrations for Class II Aquifers
Orders of
Magnitude of
Increase in
Maximum Allowable
Depth of Soil Location Sludge Pollutant
Between Landfill of Property Soil Organic Concentrations
and Aquifer Boundary Carbon Content Pollutant over Baseline
1-m and 5-m 50-m, 150-m
and 500 -m
1-m and 5-m 50-m, 150-m
and 500 -m
1-m and 5-m 50-m, 150-m
and 500 -m
1-m and 5-m 50-m
150-m
500-m
10 -m

10-m

1-m 1000-m
5-m and 10-m 1000-m
5-m and 10-m 1000-m
5-m and 10-m 1000-m
0.
0.
0,
0,
0,
0.
0,

0,

0.
0
0,
0,
0.
,0001
.0001
.01
.01
.01
.01
.0001

.01

.01
.0001
.0001
.01
.01
DDT
All regulated
pollutants
other than DDT
DDT
BEHP
Lindane
Lindane
Lindane
DDT
Lindane
BEHP
DDT
All regulated
pollutants
All regulated
pollutants
BEHP
All regulated
1
Insignificant
1
1
3
3
1
1
1
1
1
Insignificant
Insignificant
1
Insignificant
                                      pollutants
                                      other  than  BEHP
                             4-7

-------
4.2  EFFECT OF RECHARGE RATE

    The second set of sensitivity analyses evaluated the effect of recharge
rates on maximum allowable sludge concentrations.   The net recharge rate is
the amount of rain water that seeps through the landfill and the underlying
soil into the ground water.  It is  calculated as the average annual amount of
rainfall minus losses from evaporation to the air and transpiration by plants.
Recharge rate does not affect the maximum allowable pollutant concentrations
in sludge for Class I ground waters.   For the Class I analysis, the leachate
itself must meet human health criteria,  thus the rate at which the leachate is
added to ground water is not important.   For the Class II analysis, however,
the recharge rate has some effect.

    The highest national average recharge rate (0.5 m/yr) was assumed for the
baseline case.  A high value was chosen because the higher the recharge rate,
the more rapidly the pollutants are flushed into the ground water.  The
sensitivity analyses examined lower net recharge values of 0.25 m/yr and
0.00635 m/yr.  The 0.25 m/yr recharge rate did not cause a large increase in
the allowable sludge concentrations;  the increase was only a factor of two to
three whether the property boundary was set at 50 m, 150 m, 500 m, or 1,000 m.
In contrast, the very low (0.00635  m/yr) recharge rate caused order-of-
magnitude increases in allowable sludge concentrations for both metals and
organics.   For Class II ground waters at 50-m and 150-m boundaries, the
0.00635-m/yr recharge rate increased allowable sludge concentrations by three
orders of magnitude for arsenic and cadmium and by one order of magnitude for
the other pollutants.   For Class II ground waters at 500-m and 1,000-m
boundaries,  the 0.00635-m/yr recharge rate increased allowable sludge
concentrations by two orders of magnitude for cadmium and one order of
magnitude for the other pollutants.
                                    4-f

-------
4.3  EFFECT OF GROUNDWATER VELOCITY

    The third set of sensitivity analyses evaluated the effect of groundwater
velocity on maximum allowable sludge concentrations.  Groundwater velocity is
a function of gradient and hydraulic conductivity of the groundwater zone.
The baseline groundwater velocity is 100 m/yr based on a gradient of 0.005 m/m
and a hydraulic conductivity of 2,000 m/yr.  The sensitivity analysis examined
the effect of raising the groundwater velocity to 1,000 m/yr (based on a
gradient of 0.1 m/m and hydraulic conductivity of 1,000 m/yr) and lowering it
to either 10 m/yr (based on a gradient of 0.005 m/m and hydraulic conductivity
of 200 m/yr) or 1 m/yr (based on a gradient of 0.0001 m/m and hydraulic
conductivity of 1,000 m/yr).  Table 4-4 presents the results of these
analyses.

    The  sensitivity analyses demonstrated that high groundwater velocity
 (1,000 m/yr) tends to increase allowable sludge concentrations because it
provides greater dilution of the contaminants as they enter the aquifer.  For
degradable organics, however, increased dilution at higher velocities may be
offset by a  decrease in travel time to the property boundary, which reduces
the time in which decay can occur before the sludge contaminants reach the
boundary.

    Groundwater velocity was generally a relatively insensitive parameter for
all pollutants except cadmium and arsenic.  For Class I ground waters, the
variation in groundwater velocity has no effect on maximum allowable sludge
concentrations because human health criteria must be met at the point of
leachate entry into the aquifer, before the leachate is transported in the
aquifer.  For Class II ground waters, the high groundwater velocity of 1,000
m/yr caused a large increase in the allowable sludge concentrations for
cadmium and arsenic independent of property boundary location (50 m, 150 m,
500 m, or 1,000 m).   The high velocity also increased the allowable sludge
concentrations for the other regulated pollutants, but by lesser amounts   At
the 150-m boundary,  a one-order-of-magnitude increase in velocity (i.e., 1,000
m/yr)  caused a three-order-of-magnitude increase in the allowable arsenic and
                                      4-9

-------
TABLE 4-4.  Effect of Groundwater Velocity on Maximum
            Allowable Sludge Concentrations



Location
Groundwater of Property
Velocity Boundary
1,000 m/yr 150 -m

10 m/yr 50 -m


10 m/yr 150-m


1 m/yr 50 -m


1 m/yr 150-m


10 m/yr 500 -m


1 m/yr 500-m


10 m/yr 1000-m
1 m/yr 1000-m





Pollutant
Cadmium
Arsenic
DDT
TCE
Lindane
DDT
TCE
Lindane
DDT
TCE
Lindane
DDT
TCE
Lindane
DDT
TCE
Lindane
DDT
TCE
Lindane
All pollutants
All pollutants
Orders of
Magnitude of
Increase in
Maximum Allowable
Sludge Pollutant
Concentrations
over Baseline
3
3
1
2
2
1
3
3
1
3
3
1
3
3
1
1
1
1
1
1
Insignificant
Insignificant
                        4-10

-------
cadmium sludge concentrations.  This increase is much greater than that which
can be explained by increased dilution.

    The lower groundwater velocities of 10 m/yr and 1 m/yr also increased the
allowable sludge concentrations over those calculated for the baseline
situation.  The most significant increases were for DDT, lindane, and
trichloroethylene at landfills with 50-m, 150-m, and 500-m boundaries.  At the
1,000-m boundary, the lower velocities did not cause significant increases in
allowable sludge concentrations for any pollutants.  The effect of groundwater
velocity was reduced at 500 m and 1,000 m because most of the chemical was
already well dispersed and degraded by the time it reached those distances,  no
matter what the velocity

4.4 EFFECT OF AQUIFER THICKNESS

    The fourth  set of sensitivity analyses evaluated the effect of aquifer
thickness, or the depth of an aquifer, on maximum allowable sludge
concentrations.  The greater the aquifer thickness, the greater the volume of
water  into which the leachate plume may diffuse.  Aquifer thickness proved to
be  a somewhat sensitive parameter.

    The reasonable worst-case situation is based on a relatively small aquifer
thickness of 15 meters.  The sensitivity analyses looked at aquifers 78.6 m
and 560 m in depth, as well as at a smaller aquifer of 5 m in depth.  Aquifer
thickness does not affect allowable sludge concentrations for Class I ground
waters because human health criteria must be met before the water in the
aquifer dilutes the contaminants.  For Class II ground waters where the
property boundary was assumed to be at 50 m, 150 m, or 500 m, the two greater
aquifer thicknesses (78.6 m and 560 m) .caused no significant increase in
allowable sludge concentrations.  The smaller thickness (5 m),  however, did
decrease the allowable sludge concentration by an order of magnitude.

    When the property boundary was assumed to be located at 1,000 m, aquifer
thickness significantly affected the allowable sludge concentrations.  At the
                                      4-11

-------
1,000-m boundary, the two thicker aquifers increased allowable sludge
concentrations by an order of magnitude for arsenic and two orders of
magnitude for cadmium.  The thinner aquifer decreased allowable sludge
concentrations by one order of magnitude.
4.5 EFFECT OF Eh AND pH

    The fifth set of sensitivity analyses examined the effect of ground water
Eh and pH on maximum allowable sludge concentrations.   Eh denotes the
potential required to transfer electrons from the oxidant to the reductant,
and pH denotes the negative log of the hydrogen ion concentration.   At the
point where leachate enters the ground water,  the landfill model reduces
groundwater metal concentrations to the solubility limit of the metal.  The
amount of metal that precipitates out of solution depends on the Eh and pH of
the ground water.

    Ground water with a high Eh and a low pH will keep most metals in the
dissolved state --a more hazardous situation.   The reasonable worst-case
values are an Eh of +500 millivolts (mv) and a pH of 6 standard units (su).
Ground water with a low Eh and a high pH is more likely to cause metals to
precipitate out of solution, so higher metal concentrations can be allowed in
the sludge.

    The sensitivity analyses examined the effect of a moderate Eh condition  of
+150 mv and a pH of 6,  as well as an Eh condition of -200 mv and a pH of 7.
Only the latter Eh and pH conditions had much effect on allowable sludge
concentrations.

    For Class I ground waters, an Eh of -200 mv and a pH of 7 caused an
increase in the allowable sludge concentrations of three orders of magnitude
for arsenic,  one order of magnitude for copper, and two orders of magnitude
for lead and nickel.   For Class II ground waters at a 50-m boundary, this
                                       4-12

-------
condition caused a three-order-of-magnitude increase in sludge concentrations
for arsenic and a one-order-of-magnitude increase for lead.
4.6  EFFECT OF SLUDGE MOISTURE CONTENT

    The sixth and final set of sensitivity analyses evaluated the effect of
sludge moisture content on maximum allowable sludge concentrations.   The
reasonable worst-case value for sludge moisture content is 80%.   Sludges with
higher moisture content were expected to increase allowable sludge
concentrations because they contain a smaller proportion of contaminated
solids.  Sludges with lower moisture content were expected to decrease
allowable concentrations because they contain a higher proportion of
contaminated solids.  The sensitivity analyses examined the effect of a higher
moisture content (95%) and a lower moisture content (60%).

     Sludge moisture content proved to be a relatively insensitive parameter.
For  Class I  ground waters, use of a 95% moisture sludge did not significantly
increase the allowable sludge concentrations and use of a 60% moisture sludge
did  not significantly decrease the allowable sludge concentrations.   For Class
II ground waters at 50 m, 150 m, 500 m, and 1,000 m, the analysis showed that
use  of a 95% moisture sludge would increase the allowable sludge
concentrations by an order of magnitude, whereas use of a 60% moisture sludge
would decrease allowable sludge concentrations by less than an order of
magnitude..
                                       4-13

-------
                                SECTION FIVE
                            POLLUTANT LIMITS
    The proposed 405(d) sewage sludge regulations are based on maximum
pollutant limits that have been calculated for each sludge pollutant evaluated
for this regulation.  The Agency selected reasonable worst-case values for
monofill site characteristics (detailed in Section 3) to calculate these
maximum allowable sludge concentrations (pollutant limits) using the
methodology in Section 2.  Appendix C discusses methods for determining
site-specific parameters in more detail.

    The pollutant limits are set based on the classification of the aquifer
underlying the monofill.  The depth to ground water and the "point of
compliance," or the point at which the ground water must meet the health
effects level, vary with the classification of the underlying aquifer.  These
classifications, which are defined in Section 2,  are discussed below:
    •  If the monofill is located over a Class I aquifer,  the depth to ground
       water is set at zero and the health effects level must be met at the
       edge of the sewage sludge unit (point of compliance)
    •  If the monofill is located over either a Class II or  Class III(A2)
       aquifer, or a Class III(Al) or Class III(B) aquifer with total
       dissolved solids concentrations exceeding 10,000 mg/L, the depth to
       ground water is set at 1 m and the health effects level must be met 150
       m from the edge of the sewage sludge unit or at the property boundary,
       whichever is less (point of exposure)
    •  If the monofill is located over either a Class III(Al) or Class III(B)
       aquifer and the background concentration of one or more pollutants  in
       the ground water exceeds the health effects level for the pollutant(s),
       then the depth to ground water is set at 1 m,  and the background
       concentration of those pollutants must be met 150 m from the edge of
       the sewage sludge unit or at the property boundary, whichever is less.

    For the regulatory requirements to be met, the pollutant concentrations in
the sludge cannot result in groundwater pollutant concentrations that exceed
the health effects levels for those pollutants (listed in Section 3) unless
the background pollutant concentrations in the ground water  exceed those
                                  5-1

-------
levels.  Table 5-1 presents the maximum sludge pollutant concentrations  (dry
weight) for each pollutant in mg/kg for two major groups of ground water
types.  The first column presents the limits applicable to monofills  located
over Class I aquifers.  The second column presents the sludge pollutant  limits
for monofills located over most other aquifer types.  If none of the  pollutant
concentrations in a sludge exceed the specified limits for the groundwater
classification of the aquifer underlying the monofill, then the sludge may be
placed in that monofill.

    In some instances, the owner/operator cannot or may not want to use  the
sludge pollutant limits specified in Table 5-1.  First, some monofills may be
located over an aquifer with background concentrations of one or more
pollutants exceeding the health effects levels.  When this situation  occurs,
the sludge must meet pollutant limits equal to the background concentration of
the underlying aquifer for any pollutants whose concentrations in the aquifer
exceed the health effects levels.  Thus sludge pollutant concentrations  for
monofills located over this type of aquifer must be set on a case-by-case
basis using the existing background concentrations in the ground water and
back-calculating using SLUDGEMAN (with the reasonable-worst-case values from
tables in Section 3) to generate modified maximum allowable sludge
concentrations.

    Second, some monofills located over Class II or III aquifers may  have
property boundaries that are less than 150 m from the edge of the unit (thus
the relevant point of compliance is different from that used to derive the
pollutant limits in Table 5-1).  In these cases, a set of modified maximum
allowable sludge concentrations must be calculated using the actual boundary
distance as the point of compliance.

    Finally,  if one or more of the pollutant concentrations in the sludge to
be disposed exceeds the maximum allowable concentrations, then the regulation
allows for certain site-specific parameters to be varied on a case-by-case
basis.   The site-specific parameters that the regulation allows to be varied
were selected as those which caused the most significant increase or  decrease
in allowable  sludge concentrations when the sensitivity analyses were
performed (see Section 4).   These sensitivity analyses were run on the
                                   5-2

-------
        TABLE 5-1.   Maximum Sewage Sludge Concentration
                       (mg/kg dry weight)
Monofill over
Monofill over Class II/Class III(A2)/
Class I Class III(Al) -Class III(B)a
Pollutant Ground Water Ground Water
Arsenic
Benzene
Benzo(a)pyrene
Bis(2-ethylhexyl)
phthalate
Cadmium
Chlordane
Copper
DDT/DDE/DDD (total)"
Dimethylnitrosamine
Lead
Lindane
Mercury
Nickel
Polychlorinated
biphenyls
Trichloroethylene
Toxaphene
0.20
0.28
97
4.5
0.040
180
8.4
0.95
0.0019
0.35
2.3
0.0070
7
49
4.1
0.36
24
0.
250
1,600
9.


51
0.
530
75
26

49
51
1.

,85


.6



070






,1
aGround water meets  definition  of either Class III(Al) or  Class  III(B)
 ground water and the total dissolved solids concentration exceeds  10,000
 mg/L in the ground water.

"DDT -- Bis l,l-(4-chlorophenyl)-2,2,2-trichloroethane
 DDE -- Bis 1,1-(4-chlorophenyl)-2,2-dichloroethylene
 ODD -- Bis 1,1-(4-chlorophenyl)-2,2-dicloroethane
                              5-3

-------
following parameters:   depth to ground water and organic carbon content of the
unsaturated zone;  net recharge rates;  groundwater gradient and hydraulic
conductivity of the saturated zone;  aquifer thickness; Eh and pH of the
saturated zone; and sludge moisture content.  The depth to ground water, Eh
and pH of the saturated zone, and net recharge rates were identified in the
sensitivity analyses as the parameters that can be varied on a site-specific
basis.  In addition to these parameters,  soil type and pollutant partition
coefficient are also allowed to vary.   When the standard parameter values are
replaced by these site-specific values, the risk assessment model SLUDGEMAN
generates the set of modified maximum allowable sludge concentrations that
must be met before the sludge can be disposed.

    If the sludge concentrations of one or more pollutants exceed the modified
maximum allowable sludge concentrations,  then the sludge may not be monofilled
unless the pollutant concentrations  in the sludge can be reduced below the
modified maximum allowable levels.

    Figure 5-1 shows how pollutant limits,  pathogen and vector attraction
reduction requirements,  and management practices determine whether sewage
sludge may be monofilled.
                                   5-4

-------
   SEWAGE SLUDGE  MONOFILL
      Sewage Sludge

 National Limits      Case-by-Case Limits
Distance from sewage sludge
unit boundary to monofill
property One £150 meters.
           I
       No
Yes
Determine pollutant limits
using actual distance from
sewage sludge unit boundary
to monoflll property line.
Ground water classified as
Class I, Class U or as Class II
due to IDS * 10,000 mg/l or
yield < 150gal/d.
       No
Determine pollutant limits
using existing pollutant
concentrations In ground water.
                                   ri
                Yes
Determine pollutant limits
from Table 5.
                Yes
                       No
Comply with pollutant Omits.
             Determine pollutant limits using
             site-specific value for
             up to six Input parameters.
  Pollutant Limits
  Management Practice
  Monitoring and reporting
              Comply with pollutant limits.
                            No
                             Do not place sewage sludge In monoflll.
             Figure 5-1.   Sewage Sludge Monoflll
                            5-5

-------
                                SECTION SIX
                     GENERAL SITING REQUIREMENTS
    When siting a monofill,  special consideration must be  given  to  evaluating
sites near airports,  100-year floodplains,  wetlands,  fault areas, seismic
impact zones, and unstable areas.   Requirements  for  siting monofills  in  each
of these types of locations have been established by the proposed sewage
sludge regulations to prevent adverse impacts  to human health  and the
environment.  The following sections discuss  the potential impacts  associated
with the six types of locations and present the  rationales used  to  develop
these requirements.
6.1 AIRPORT SITING REQUIREMENTS

    An aircraft/bird strike is defined as any contact  between  a  moving
aircraft and a bird or group of birds.   In response  to the  increasing problem
of bird strikes at airports located near municipal  solid waste disposal
facilities, the Federal Aviation Administration (FAA)  issued Order  5200.5  on
October 16, 1974.  The order states that landfills  located  within 10,000 ft of
any runway used by turbojet aircraft,  or within 5,000  ft of any  runway used
only by piston-type aircraft,  should be closed.   It  also recommends  the
closing of any landfill located such that it places  the airport  runways or
aircraft flight patterns between bird feeding,  nesting,  or  roosting  areas.
    6.1.1 Impacts of Siting Facilities near Airports

    The major problem in siting monofills  near airports  is  the  high incidence
of bird collisions with airplanes.   This hazard is  caused by  the  large  numbers
of seagulls and other flocking birds that  frequent  landfill areas.   The
                                     6-1

-------
results of collisions between birds and aircraft range in severity from dents
or holes in the aircraft structure to aircraft accidents and loss of life.
Birds can cause aircraft accidents by penetrating windshields and disabling
crew members or by striking and deforming the turbine engines or other
aircraft parts (Solman, 1973).  Bird strikes on windshields may crack,
shatter, or completely destroy a panel,  exposing pilots to flying pieces of
glass, bird debris, and high wind velocity.   In addition, bird strikes to
windshields may startle pilots, impair their judgment, or distract their
attention (Blokpoel, 1976).

    The majority of bird strikes occur on the forward facing parts of the
aircraft. Wide-bodied aircraft have a higher risk of colliding with birds
because they have large frontal areas and large air intakes (Blokpoel, 1976).
Table 6-1 presents statistics for military aviation in the United States in
1973, indicating the distribution of bird strikes by aircraft part struck
(Blokpoel, 1976).

    Because of high aircraft velocities,  a bird strike can create an enormous
impact. A 4-pound bird (such as a mallard duck) hit by an aircraft at 300
miles per hour (mph) causes an impact with a force of 15 tons over a saucer-
sized area.

    For a collision at 600 mph, the force of this impact would be nearly 60
tons (Solman,  1973).  Statistics for civil aviation in the United Kingdom and
the Soviet Union indicate that over two-thirds of all bird strikes occur at
speeds of 92-184 mph (Blokpoel, 1976).

    Bird strikes pose a greater hazard to jet aircraft than to propeller
aircraft (Department of Interior,  1978).   The rotating blades of a propeller
aircraft tend to protect the piston engine,  whereas turbine engines are
usually exposed to direct bird ingestion, which can deform or destroy the
rotor and stator blades of the engine's  compressor (Blokpoel, 1976).
                                     6-2

-------
TABLE 6-1. Distribution of Bird Strikes by Aircraft Part Struck for U.S. Military
            Aviation (1973)
             Aircraft Part
Percentage of Bird  Strikes (%)
             Wing

             Tail

             Nose

             Windshield

             Engine

             Landing Gear

             Other
            27.8

             1.6

             1.9

             5.5

            32.8

             2.7

            17.7
 Source:   Blokpoel, 1976.
                                         6-3

-------
    Observations of daily, seasonal,  and operational patterns of bird strikes
at airports have revealed that an estimated 75% of bird/aircraft collisions
occur during takeoff and landing (Blokpoel, 1976).  These collisions pose a
serious hazard to aircraft because any sudden loss of power or control during
this time can be particularly dangerous (Ultrasystems,  Inc., 1977).   Studies
have determined that over 62% of bird strikes occur below altitudes of 500 ft
(FAA, 1974) .   Air Force statistics for 1972 indicate that 86% of bird strikes
occurred below 2,000 ft, and 93% occurred below 3,000 ft (Blokpoel, 1976).
Impact altitude statistics compiled by the FAA (FAA, 1978)  agree with these
percentages.
    6.1.2  Regulatory Requirement for Siting Monofills near Airports

    Because each airport presents a unique topographical and ecological
environment, uniform national standards for monofills located near airports
are not appropriate.  Each airport environment must be considered individually
to assess the bird-strike hazard for that area.   For this reason, EPA has
established a broad, performance-based requirement for minimizing bird strike
hazards posed by monofills.  As for standards regulating solid waste disposal
facilities  (40 CFR Part 257) and those regulating municipal solid waste
landfills (40 CFR Part 258), the requirements for sewage sludge monofills
adopt the minimum distances from airport runways specified in FAA Order
5200.5.  Sixty-two percent of all bird strikes occur below altitudes of 500
ft, and aircraft are generally below this altitude within the distances
specified in the FAA Order (44 FR 53459, September 13, 1979).  EPA therefore
believes this restriction will prevent most bird/aircraft collisions caused by
the proximity of monofills to airports, without placing an undue burden on the
regulated community.

    The distance from the runway to the boundary of the monofill is measured
radially from the end of the runway to the boundary.  The distance can be
determined using recent United States Geological Survey (USGS) 7-1/2-minute
                                      6-4

-------
maps, scale aerial photographs of the area, or plot plans of the facility and
the surrounding area  (EPA, 1980).
6.2 FLOODPLAIN SITING REQUIREMENTS

    Large regions of the United States are susceptible to flooding (see
Figure 6-1)  (GCA, 1986a).  Monofills sited in these regions can pose threats
to human health and the environment in a variety of ways.  Flooding can cause
erosion of landfill cover material, allowing increased infiltration of water
through the  final cover or through any joints between covers and liners.
Increased water content in the monofill can lead to increased leachate
production,  with increased potential for surface and groundwater
contamination.  The large water volumes and high flow velocity associated with
floods can cause washout of wastes, also leading to surface-water and
groundwater  contamination.  Wave action and flowing water can destroy
containment  structures and levees, and underseepage can weaken them.  Weakened
containment  structures can increase the vulnerability of monofills during
future flooding activity.  Finally, flooding can relocate stream channels near
the monofill,  causing or worsening runon to the working face of the facility
 (MITRE, 1980;  MRI, 1984).
     6.2.1  Types of Floods Occurring in 100-yr Floodplains

     The magnitude of a  flood is usually described by its statistical frequency
 of  occurrence.  According to MRI (1984),  "The differences between 10-, 100-,
 and 500-year floodplains are most commonly differences in elevation and size
 of  area inundated."  Floods occurring in  floodplains can be divided into two
 categories:  floods due  to increased water elevation and coastal floods
 (MITRE, 1980).
                                      6-5

-------
a\

o\
                                                                 areas  that  have  serious agricultural,
                                                                 urban,  and  other flooding
                 FIGURE 6-1.   Existing Flooding Problems in the United States (Water Resources Council, 1978)

-------
    The types of flooding due to increased water elevation or flow velocity

include riverine floods, shallow floods, sheet runoff, ponding, lacustrine

floods, and alluvial fan flooding.  These types are described below  (MITRE,
1980):
    •  Riverine floods -- A riverine flood is the overflow of channelized
       water onto the surrounding floodplain.  The velocity of a riverine
       flood can reach 30 ft/sec, which is enough to wash out the contents of
       a landfill.

    •  Shallow floods -- A shallow flood is an unconfined flood occurring in a
       topographically low area. Shallow floods include sheet runoff, which is
       "the broad unconfined downslope movement of water across gently sloping
       terrain" and ponding, which is "the accumulation of runoff or flow in a
       depression that has no natural or manmade subterranean or rim outlets,
       culverts, or pumping stations."

    •  Lacustrine floods -- A lacustrine flood results from the increase in
       elevation of a lake due  to seasonal and long-term water fluctuations.

    •  Alluvial fan flooding -- Although flooding in an alluvial fan often
       follows  the existing stream channels, unpredictable channel flow is
       common.  Landfill containment structures can be threatened when the
       direction of channelized flow, predicted to be parallel to dikes and
       levees, becomes perpendicular.  A flood with a velocity of 4 to 6
       ft/sec can be sufficient to disintegrate an earthen levee.

    Coastal flooding is defined as flooding accompanied by wave action.

Facilities 500  ft inland can sustain severe damage during a 100-yr storm, and
even facilities 1,000-2,000 ft  inland have been known to sustain damage,

particularly if they were not elevated above the height of the incoming waves

(MITRE, 1980).  Monofills in such locations would be subject to daily tides,

wave setup, tsunamis (tidal waves), storm surges, and wind surges.
    6.2.2  The History of the 100-yr Floodplain as an EPA Regulatory Standard


    Executive Order (EO) 11988, signed into effect on May 24,  1977,  requires
that each Federal agency "shall provide leadership and shall take  action  to
reduce the risk of flood loss, to minimize the impacts of floods on  human
safety, health and welfare, and to restore and preserve the natural  and
                                      6-7

-------
beneficial values served by floodplains in carrying out its responsibilities"
(EO 11988, 1977).  EPA addressed this order in the Criteria for Classification
of Solid Waste Disposal Facilities (44 FR 53438,  September 13, 1979) by
requiring that "facilities or practices in 100-yr floodplains shall not
restrict the flow of the base flood,  reduce the temporary water storage
capacity of the floodplain, or result in wash out of solid waste, so as to
pose a hazard to human life, wildlife, or land or water resources"  (40 CFR
Part 257.3-1).  EPA has used an almost identical requirement in its rule for
municipal solid waste landfills and for sewage sludge monofills.

    EPA considered many factors in its choice of the 100-yr floodplain as its
regulatory standard.  When EPA promulgated regulations for hazardous waste
management facilities located in floodplains (40 CFR Part 264.18b). EPA
considered using the 500-yr floodplain designation rather than the 100-yr
designation.  The U.S.  Water Resources Council (WRC) recommends restricting
"critical actions," defined as "any activity for which even a slight chance of
flooding would be too great" in the 500-yr floodplain (43 FR 6030, February
10, 1978).  Initially,  EPA decided that hazardous waste management facilities
were "critical activities" and proposed restricting their activity in the 500-
yr floodplain.  Because of almost unanimous opposition to the proposed
standard (EPA, 1983), however, EPA adopted the 100-yr floodplain restriction
in its final rule (46 FR 2847, January 12, 1981).  This decision took into
account the following (EPA, 1983):

    •  EO 11988 does not authorize regulation of activities in the 500-yr
       floodplain.
    •  EPA did not have sufficient information to justify use of the 500-yr
       floodplain designation.
    •  Maps of the 500-yr floodplain  were available for only very limited
       portions of the  United States.   The development of 500-yr floodplain
       maps would place a large financial burden on the regulated community.
    •  Use of the 500-yr floodplain designation would restrict large areas of
       the United States,  such as the mid-Atlantic region, the Southeast, and
       the Gulf States.
                                     6-8

-------
    •  The 100-yr floodplain is the designation established for use by the
       U.S. Geological Survey, the U.S. Army Corps of Engineers, the Federal
       Insurance Administration, and many other agencies.

    The Agency determined, therefore, that the 100-yr floodplain was the
appropriate regulatory standard for both hazardous waste facilities and sewage
sludge monofills.  The Agency's selection of the 100-yr floodplain standard
was supported by analyses of present and past environmental impacts associated
with washouts at waste management facilities.  An examination of environmental
impacts linked to the flooding of these facilities justified the regulatory
view that  the 100-yr floodplain criterion poses minimal environmental impact.
    6.23  Impacts of Siting Facilities in Floodplains

    The potential for contaminant  releases from facilities located in flood-
prone areas is considerable.  The  cause and severity of release can range from
increased leachate production in inundated landfills to a complete washout of
facilities.  The  destructive forces associated with floods depend on location,
depth, velocities, flood duration, speed of onset, groundwater level, amount
of debris in the  flood waters, and chemical properties of the sewage sludge.
These factors limit the time for implementation of emergency measures aimed at
protecting the facility or removing wastes to a safe location.  A discussion
of these factors  follows:
       Location -- Facilities located in the middle of a 100-yr floodplain are
       more likely to be inundated from all sides by the 100-yr flood, whereas
       facilities located on the edge of the 100-yr floodplain are more likely
       to have only one side exposed to the flood source (MITRE, 1980).
       Proximity of other structures -- Close proximity of other structures to
       landfills will increase floodwater elevations and can increase flow
       velocities downstream.  Nearby structures can expose the landfill to
       channeling effects,  and the landfill can cause or exacerbate a channel
       effect on structures downstream from the facility (MITRE, 1980).
                                      6-9

-------
    .  Flood depth -- Depth of the flood waters determines the strength of the
       hydrostatic forces in effect during the flood.  Vertical loading can
       cause uplift and lateral displacement of wastes and is directly related
       to leachate generation.  Horizontal loading can cause washout of wastes
       (MRI, 1984).

    .  Floodwater velocity -- Floodwater velocity affects the momentum and
       damage potential of the flood waters.  As floodwater velocity
       increases, erosion of cover material tends to increase, causing damage
       to landfill structures.  Floodwater velocity also affects the momentum
       and damage potential of the debris and sediment carried by the flood
       (MRI, 1984).

    •  Duration of flooding -- The duration of a flood affects the degree to
       which soils and building materials are saturated, contributing to their
       weakness, and increases the magnitude of leachate generation and
       leachate seeps (MRI, 1984).

    •  Speed of flood's onset -- Speed of a flood's onset is significant
       because it determines the warning time that monofill personnel will
       have to initiate emergency procedures to prevent washout of sewage
       sludge.

    •  Groundwater level -- Groundwater level at the time of flooding is an
       important factor in determining the impact of the flood on the
       integrity of landfill structures.

    •  Sediment and debris content of flood -- In addition to causing impact
       damage,  sediment and debris from a flood can bury waste.  Hidden from
       view, these wastes can potentially endanger human health and the
       environment.

    •  Chemical properties of sewage sludge -- the chemical characteristics of
       the sewage sludge in the monofill can affect their rate of dispersion
       following washout from the landfill.  According to one theory (MRI,
       1984),  chemical constituents that tend to be widely diluted and
       dispersed by the flood waters cause the least adverse impacts on human
       health and the environment, whereas chemical constituents that remain
       concentrated in a small area will tend to cause greater impacts.
       Chemical properties that tend to increase the dispersion and dilution
       rates of constituents are water solubility, hydrolytic behavior and
       rate of volatilization, adsorption to suspended particulates and
       sediment, and biodegradation (MRI, 1984).


    Because flooding is a surface-water phenomenon, surface waters are the

major recipients of contaminants.  When contaminants enter surface waters,

they migrate rapidly to downstream waterways.  The rapid transport processes

produce large  areas of surface water contamination.  In coastal or estuarine
                                     6-10

-------
areas, tidal effects can disperse contaminants both upstream and downstream of
the source.  Although mixing and dispersion generally dilute contaminant
concentrations far from the source, contaminant adsorption on sediments can
produce a long-term problem.  Contaminated sediments will be both dispersed
over the inundated land surfaces and transported downstream as part of the
river sediment load after the flood subsides, resulting in widespread
contamination.

    Many contaminants that tend to adsorb on sediments (i.e., many organics
and heavy metals) will remain long after soluble and suspended contaminants
have been swept downstream.  Suspended contaminants will tend to settle in
slow-moving portions of the river or downstream reservoirs.  In coastal areas,
they may spread up and down the coast as well as offshore, producing long-term
contamination problems that can adversely affect downstream water supplies and
aquatic resources many years after the source of contamination has been
cleaned up.  Contaminants in sediments will continue to leach back into
surrounding surface waters and contaminate surface waters downstream.  There,
they may destroy benthic organisms or enter the benthic food chain, resulting
in toxic effects at higher trophic levels, i.e., important fisheries.
Recreational use of the waters may also be impaired.

    Contamination of surface waters and sediments due to releases from waste
management facilities can destroy aquatic organisms directly through toxic
effects, including accumulation of low-level releases in the food web, and
indirectly through destruction of habitat.  Contaminated sediments may destroy
spawning grounds for fish and kill shellfish and other benthic invertebrates
that inhabit the sediments.  Fisheries may be damaged in turn due to the
elimination of the benthic food supply or through the consumption of
contaminated organisms by fish.  Destruction of spawning habitat and toxicity
of the waters to sensitive, early life stages may also limit the reproductive
success of fisheries.   Other indirect effects include changes in species
composition and diversity when sensitive species are eliminated and replaced
by less desirable pollution-tolerant species.  In severe cases, all organisms
near the release may be destroyed.
                                     6-11

-------
    The release of wastes to surface waters also may result  in both acute and
chronic human-health effects.  The primary route of exposure  is  through the
ingestion of drinking water.  The ingestion of fish and other aquatic
organisms that accumulate chemicals is also of concern.  Human-health effects
may exist at lower levels of bioaccumulation than those which affect
indigenous aquatic organisms.  Recreational use of surface water for water-
contact activities such as swimming can also result in contaminant  exposure.
A major concern associated with the effects of surface-water  contamination on
human health is that existing ambient water-quality criteria  for human toxic
and carcinogenic protection are in many cases below the detection limits  in
water.  Potentially toxic releases from waste management facilities can
therefore go undetected.  Additionally, the human-health effects of chronic
exposures may not be exhibited for decades.

    Surface waters represent an economic asset to regional and local areas.
Contaminant releases to surface waters that result in widespread,  long-term
degradation of water quality can affect agricultural and industrial use,  i.e.,
food processing.  Any degradation of water quality will result in a loss  to
the community.
    6.2.4  Preventive Measures and Emergency Responses to Flooding of Facilities

    It is difficult and expensive to design preventive measures  that  can
withstand the forces of a major flood.  The two major approaches  are  (1)  flood
protection measures that rely on diversion structures such as  levees,  dikes,
and floodwalls to divert the flood waters away from units and  prevent
inundation and (2) flood-proofing measures that allow the flood  waters to come
in contact with units,  but that include design features to prevent  damage.
The latter approach includes designing fencing units to prevent  impacts from
floating debris,  grading landfills to maximize runoff and minimize  erosion,
and providing drainage systems to facilitate the collection  and  removal of
runon and runoff (MITRE, 1980).
                                     6-12

-------
    Emergency responses to contaminant releases caused by flooding are
difficult to implement and generally not very effective.  In the event of a
washout or major release, wastes usually cannot be recovered.  Preventive
measures, such as moving waste to a safe location or erecting flood protection
structures prior to an encroaching flood, are also difficult to implement due
to the difficult working conditions and the general disruption of
transportation systems (such as access roads) and other services that
generally occurs during floods.

    When contaminants are released into surface waters, they spread rapidly
over large areas.  This rapid  spreading may result in long-term sediment
contamination that extends far downstream, as well as soil contamination in
downstream land areas inundated during the flood.  These problems may persist
for many years after the facility has been cleaned up.  Offsite removal of
contaminated sediments generally is not feasible due to the large extent of
the affected areas.

    It  is generally impossible to monitor a release during a flood because
rapid transport and dilution typically move the peak concentrations of surface
water contaminants far downstream before they can be measured.  Site access is
also a problem during a flood.  Even if the site is accessible, a major
sampling effort would be required to characterize the temporal and spatial
variations in pollutant concentrations.   These variations are very important
because of the dynamics of the contaminant release and flow conditions.
Because of the difficulty in assembling a sampling team given the short lead
time and hazardous working conditions during floods,  the monitoring of
sediments and surface-water concentrations usually must wait until after the
flood has subsided.  Monitoring fish-tissue concentrations and biological
impacts such as changes in abundance, species composition, and diversity also
is important, but this task involves a major long-term effort because
important changes often occur gradually
                                     6-13

-------
    6.2.5  Case Studies

    EPA has examined case studies that depict many of the problems  associated
with locating waste management facilities in floodplains (EPA, 1988a).   These
studies illustrate (1) the potential for waste releases in floodplains,  (2)
the common release pathways, and (3) the potential impacts associated with
these releases.  The observed waste releases were caused by flooding of  waste
sites, dike failures, streambank erosion, contaminated runoff, or shallow
groundwater contamination recharging a nearby stream.  In all cases,
continuous or frequent release to nearby surface waters occurred due to
failures in monofill design and operating specifications.  Flooding, however,
had been responsible for rapid dispersion of a large quantity of contaminants,
Environmental impacts observed included surface-water contamination, fish and
aquatic organism kills,  and long-term sediment contamination.
    6.2.6  Regulatory Requirement for Siting Monofills in Floodplains

    EPA's requirement states that a sewage sludge monofill shall not restrict
the flow of a base (100-yr) flood;  reduce the temporary water storage capacity
of a floodplain; or present a hazard to human health, wildlife, and land and
water resources because of a washout of sewage sludge.  Monofills can employ a
variety of flood controls to meet this requirement, several of which follow
(MITRE, 1980):

    •  Slope -- Location of monofills below grade causes ponding that can
       carry wastes out of the monofill in solution or suspension and increase
       leachate production. A unit  slope greater than 2% but less than 5% will
       inhibit the ponding effect,  but will not lead to increased erosion.
    •  Drainage capacity -- A leachate collection system can be used during
       emergencies to increase the  drainage capacity of a landfill.  Permanent
       drainage channels or ditches should be constructed on the uphill side
       of the monofill to divert water around the site.  Portable drainage
       structures can be used during flooding; however, the speed of flood
       onset must be considered in  choosing such structures for flood
       protection.
                                     6-14

-------
    •   Fencing --  Any fencing used around a monofill should be permeable.
       Permeable fences will allow water to pass  through,  making them less
       likely to be carried away by flood waters  and reducing the potential
       impact damage caused by debris in the flood waters.

    •   Diversion structures -- Levees are the most commonly used diversion
       structure;  however,  flood walls and ditches can also be used.   Levees
       are generally constructed of earthen materials and  are designed to
       provide flood protection from seasonal high water.   They are,  however,
       subject to failure from underseepage as a  result of flood inundation.
       Flood walls are constructed of construction materials such as  concrete
       or steel sheet piping and are designed to  prevent inundation of
       adj acent land.

    The first step in determining compliance with the requirement is  to

determine whether the monofill is located in a 100-yr floodplain.   This

information can be obtained from existing permits and operation applications
or from 100-yr floodplain maps.  These maps are available  from the following
sources (EPA, 1980) :


    •  State flood control agencies or other departments

    •  Federal Emergency Management Agency (FEMA),  Flood Insurance Rate Map
       (FIRM), or Flood Hazard Boundary Map (FHBM)

    •  Local and regional planning and zoning agencies

    •  Soil Conservation Service,  U.S.  Department of Agriculture

    •  U.S. Army Corps of Engineers

    •  National Oceanic and Atmospheric Administration

    •  Federal Housing Administration (HUD)

    •  U.S. Geological Survey

    •   Bureau of Land Management,  U.S.  Department of the Interior

    •   Bureau of Reclamation,  U.S.  Department of  the Interior

    •   Tennessee Valley Authority

    •   River basin commissions and special flood  control districts

    •   Local and State agencies involved with public works  construction (i.e. ,
       bridges,  culverts,  highways, channel improvements,  and urbanization
       studies)


                                     6-15

-------
Additional assistance can be obtained from the State agency  charged with flood
protection or floodplain management, any of the map-source agencies with the
necessary expertise previously listed, or a qualified professional  firm.

    After determining location with respect to 100-yr floodplains,  an owner or
operator should determine if the facility is protected from  washout by a 100-
yr flood (EPA, 1980).

    Types and effectiveness of washout protection used in each  area of the
facility below the 100-yr flood level should be considered.  Washout
protection may include:

    •  Dikes
    •  Levees
    •  Benns
    •  Flexible linings
    •  Vegetative cover
    •  Riprap
    •  Diversion of high velocity flows around the facility
    .  Change in soil  matrix by chemical alteration

    Flood flow velocity should also be considered (EPA,  1980) .   A flood  flow
velocity of at least 2.5 times the average velocity over the entire  floodplain
cross section should be used for those portions of the facility in  the
floodway.   A minimum value of 1 times the average velocity over the  entire
floodplain cross section should be used for those portions of the facility in
the floodway fringe.   That is,
                                     6-16

-------
         v  =  Q/A

where  v    =  average velocity
       Q    -  100-year flood flow (cfs)
       A    =  cross-sectional area of floodplain

    Matrices comparing the efficiency of each type of washout protection with
different flood-flow velocities are available in the U.S. Department of
Transportation's Hydraulic Engineering Circular No. 15 and the U.S. Army Corps
of Engineer's Shore Protection Manual (EPA, 1980).  These matrices can be used
to help evaluate the adequacy of protection for each facility
 63 WETLANDS SITING REQUIREMENTS

    The  wetlands  of  the United States, composed in part of inland and coastal
 swamps,  bogs, marshes, sloughs, mudflats, wet meadows, natural ponds, and
 river  overflows,  serve as  important natural hydrologic, ecologic, social, and
 economic resources.   Scientific studies have come to recognize wetland
 habitats as  essential breeding, rearing, and feeding grounds for numerous
 species  of fish and  wildlife, including many endangered species.  These
 ecologically sensitive habitats have been found to play important roles in
 both flood protection and  pollution control.  The general public, government,
 and business, however, have had little concern for wetlands protection, thus
 these  areas  have been inconsistently regulated by Federal, State, and local
 governments.  Such policies resulted in the direct destruction of an estimated
 48 million acres of  wetlands through draining, dredging, and landfilling for
 agricultural, residential, and commercial development  (43 FR 4942, February 6,
 1978).   A recent study by  the Office of Technology Assessment (OTA, 1984)
 concluded  that, based, on current policies and trends, an estimated 300,000
 acres  of wetland resources are lost each year.  Increasing scientific
 understanding of the functions and values of wetlands  indicates that this
                                     6-17

-------
conversion will cause serious economic consequences throughout the country
(Baldwin, 1985).

    Despite recent concern by the public and State and Federal regulating
authorities, wetland protection programs are neither comprehensive nor
consistent (OTA, 1984).   The Clean Water Act (CWA) (Pub. L. 92-500 as amended
by Pub. L. 92-217 and Pub. L. 95-576;  33 U.S.C.  1251 et seq.) stands alone in
addressing adverse effects to wetlands by regulating impacts to "waters of the
United States."   An expansive definition of the latter has been viewed to
encompass wetlands indirectly.  The ambiguousness of the statutory language,
however, has lead to disputes over which Federal agency or agencies have
primary authority to implement a Federal regulatory program to protect
wetlands from waste disposal.  The result has been an inconsistent and often
incomprehensive wetland protection system, ultimately mandating a reevaluation
of present policy and issuance of a natural wetlands protection standard
administered solely through and by the EPA.

    The term "wetlands"  refers to those areas inundated or saturated by
surface or ground water at a frequency and over a duration sufficient to
support a prevalence of vegetation typically adapted for life in saturated
soil conditions.  Wetlands include, but are not limited to, swamps, marshes,
and bogs.  The justification for protecting wetlands focuses on the important
ecological functions and resource values that wetlands provide, including the
following (OTA, 1984):

    •  Wetlands store runoff and slow the downstream flow of water, thus
       reducing floodpeaks and frequency of flooding in downstream areas.
    •  By temporarily or permanently retaining pollutants, wetlands can
       improve, to varying degrees, the quality of the water that flows over
       and through them.
    •  Wetlands provide  food and habitat for many game and nongame animals.
       Approximately 20% of all plant and animal species listed by the Federal
       government as threatened or endangered depend heavily on wetlands.
    •  Wetlands may significantly reduce shoreline erosion caused by large
       waves and major  coastal and riverine flooding.
                                     6-18

-------
       Some wetlands are recharge areas to groundwater systems that supplement
       local or regional groundwater supplies through infiltration/percolation
       of surface water.
    63.1 Impacts of Siting Facilities in Wetlands

    Wetland environments may be adversely affected in several ways by the
proximity of solid waste land disposal facilities.  Depositing wastes into
wetlands causes physical disturbances and creates potential for the accidental
discharges of wastes into the ecosystems (GCA, 1986b).   These physical and/or
accidental impacts can directly affect the chemical,  biological, and human-use
characteristics of the aquatic ecosystems.   The rule 40 CFR 230.42(a)(3)(b)
states:

    The loss of wetlands.... is likely to damage or destroy habitat and
    adversely affect the biological productivity of wetland ecosystems by
    smothering, by dewatering, by permanently flooding, or by altering
    substrate elevation or periodicity of water movement.  The addition of
    materials may destroy wetland vegetation or result in advancement of
    succession to dry land species.   It may reduce or eliminate nutrient
    exchange by a reduction of the systems productivity,  or by altering
    current patterns and velocities.  Disruption or elimination of the
    wetlands system can degrade quality by obstructing circulation patterns
    that flush large expanses of wetland systems, by interfering with the
    filtration function of wetlands, or by changing the aquifer recharge
    capability of a wetland.  Accidental discharges can change the wetland
    habitat value for fish and wildlife.  When disruptions in flow and
    circulation patterns occur, apparently minor loss of wetland acreage may
    result in major losses through secondary impacts.

    The degradation of wetlands by foreign substance intrusion can cause the
destruction of recreational and commercial fisheries.  Placing waste materials
in wetlands can affect the suitability of recreational and commercial fishing
grounds as habitat for consumable aquatic and terrestrial organisms by
                                     6-19

-------
destroying migration and spawning areas, as well as food sources  (40 CFR Part
230.51b).  These natural aquatic areas also provide aesthetic,  recreational,
scientific, and educational values to the public.

    In addition, wetlands are commonly near to or contain surface  waters and
by definition have saturated soils and a shallow water table.   Therefore,  the
release of wastes often affects surface waters and ground waters surrounding
the wetlands.  Surface water transport results in extensive surface  water and
sediment contamination.  The difficulties in performing corrective actions for
widespread contamination and the extensive wetland disruption  involved in
sediment removal have been documented in case studies (EPA, 1988a).
    63.2  Current Federal Protection Measures

    President Carter advanced Federal protection of wetlands in  1977 by
signing EO 11990 for protection of wetlands and EO 11988 for floodplain
management (EO 11988 is discussed in Section 6.2).  These Federal  directives
prescribe measures to be taken by Federal agencies to avoid adverse impacts on
wetland and floodplain resources (GCA, 1986b) .

    EO 11990 articulates a strong Federal policy favoring the protection of
wetlands.  It directs Federal agencies, in carrying out their
responsibilities, to minimize the destruction or degradation of  wetlands and
to preserve and enhance their natural and beneficial values.  It also  requires
Federal agencies to avoid undertaking or providing assistance for  new
construction, including draining, dredging,  and filling, in wetland areas
unless there is no practical alternative and only if measures are  taken to
minimize harm to wetlands.   In principal, EO 11990 appears to control  Federal
activities involving waste disposal in wetlands.  In practice, however,
because Federal directives like this one are largely enforced by the Federal
agencies themselves,  it is difficult to measure the extent to which Federal
waste disposal in wetlands has been affected.  In addition, this Executive
                                     6-20

-------
Order does not apply to private, non-Federal waste disposal activities  in
wetlands (GCA, 1986b).

    The ineffectiveness of the present Federal system is demonstrated by EPA's
use of its veto authority under §404(c) of the CWA.  Although the U.S.  Army
Corps of Engineers releases about 11,000 permit requests each year, permit
denials are estimated to be less than 3%, with only a few §404(c) veto  actions
being taken by EPA.  Only about a dozen permit controversies with the Corps
have been evaluated by regional offices for resolution to the Washington
headquarters under §404(c) procedures.  The rare use of §404(c) reflects the
unusual role created by Congress for EPA as overseer of another agency's
regulatory program (Baldwin,  1985).

    Estimates of  current national wetlands loss also exemplify the problems
with Federal implementation.  Approximately 99 million acres of wetlands are
located in the 48 contiguous  States, comprising 5% of the total area (EPA,
1987b).  Of these 99 million  acres, between 300,000 and 500,000 acres of
wetland resources are adversely affected annually.  Fifty-thousand acres of
this wetlands loss are permitted under §404.  An unknown amount of loss,
occurring through discharges  that could come under §404 jurisdiction but that
are currently unregulated or  illegal, is probably equal to at least the amount
of permitted loss (EPA, 1986).  EPA believes these unnecessary losses can be
prevented through a comprehensive and consolidated Federal system that  does
not depend on the interactions of different agencies with different Federal
(EPA) administrative and substantive duties.  Such a policy would have  as its
ultimate goal the development of national criteria and standards.
    63 J  Regulatory Requirement for Siting Monofills in Wetlands

    The sewage sludge monofill criteria include provisions that impose a ban
on locating monofills in wetlands.  EPA believes this ban is necessary because
monofills cause irreparable harm to these sensitive ecosystems.  This decision
is consistent with Agency policy for the protection of the Nation's wetland
                                      6-21

-------
resources.  This policy of wetlands protection has been articulated over the
years in various Agency directives on wetlands, beginning with the policy
statement issued by the first EPA Administrator in 1973.   It also is embodied
in regulatory form in the guidelines for specification of Disposal Sites for
Dredged or Fill Material (40 CFR Part 230) effective under §404(b)(l) of the
CWA.

    Recently, the Agency has identified wetlands protection as a top priority,
aggressively implementing the §404 program,  increasing enforcement against
illegal discharges, and specifying other measures as necessary.  To this end,
the Agency considers the wetland requirement an essential measure for
protecting wetlands resources.

    For consistency with the CWA, the revised criteria adopts the definition
of wetlands used in the §404(b)(l) guidelines.  These guidelines, first
promulgated in 1975 and then amended in 1980, specify the analytical tools to
be used in evaluating and testing the impact of dredged or fill material
discharges on waters of the United States, including wetlands.  Fundamental to
the guidelines is the precept that discharges into aquatic ecosystems should
not be allowed unless it can be demonstrated that such discharges will not
have an unacceptable effect.  In particular, the guidelines identify filling
operations in wetlands as among the most severe environmental impacts.   For
this reason, the guidelines are directly relevant to solid waste disposal in
wetlands and provide the basis  for decision making with respect to such
activities.
6.4  FAULT AREA SITING REQUIREMENTS

    Earthquakes are part of the Earth's natural dynamics.  When they occur,
they are usually catastrophic,  causing the loss of life and property.  North
Americans typically associate the west coast of the continent with areas of
known seismic activity, but serious earthquake shocks have also occurred in
and near the east coast (Legget and Karrow, 1983) .
                                     6-22

-------
    Earthquakes are usually caused by movements along faults, which are
fractures in rock along which the adjacent rock surfaces are differentially
displaced.  Faults may vary in length from a few meters to many kilometers.
The presence of faults indicates that at some time in the past movement has
occurred by either a slow slip (movement along the fault plane) that produces
no ground motion, or a sudden rupture, which results in the perceptible ground
motion known as an earthquake (Bolt, 1978).

    Faults assume different geometric forms:  normal, reverse and strike-slip.
A normal  fault has movement down the dip of the rock, while a reverse or
thrust fault has movement up the dip of the rock.  Since vertical
displacements seen at the surface are produced by both normal and reverse
faults, both of these faults are referred to as dip-slip faults.  A strike-
slip  fault has a relative displacement at a right angle to the dip, as viewed
from  the  ground surface.  This type of fault is sometimes referred to as a
wrench or tear fault  (Legget and Karrow, 1983)   Strike-slip or dip-slip
faults can cause the partial or total collapse of buildings, bridges, and
tunnels;  failure of manmade and natural slopes; and damage to water or other
types of  distribution systems.

    When  displacement along a fault occurs, movements of great masses of
material  naturally develop dynamic effects of magnitude that initiate
vibrations or seismic waves within the earth's crust.  The seismic waves
travel for great distances in all directions, thereby creating effects over a
wide  area (Legget and Karrow, 1983).  Section 6.5 discusses seismic zones in
more  detail.

    The fracturing that faults represent is a normal part of the dynamic
process of geologic development.  Therefore, some faults are of great age,
whereas others seen in Pleistocene deposits are, correspondingly, very young
geologically.  The age of a fault is often related to whether or not it is
active;  young faults tend to be more active.  Only in active faults is
movement  on the fault line expected to take place in the foreseeable future.
                                      6-23

-------
The faintest possibility of movement on a fault plane under any  engineering
structures, however, should be avoided, even to the extent of  abandoning a
proposed building site (Legget and Karrow, 1983).

    Damage can also be caused by the displacement of the fault itself.   This
particular earthquake hazard is very limited in area and can usually  be
avoided by obtaining geologic advice on the location of active faults before
undertaking construction (Bolt, 1978).
    6.4.1  Impacts of Siting Facilities in Fault Areas

    Constructing a monofill over an active fault can have serious
consequences.  Facilities located directly over a fault may be  damaged,  for
example, by lining rupture, during the fault displacement.  Lining  rupture may
result in an uncontrolled release of contaminants into the environment.

    Investigating sites for surface-fault rupture is a deceptively  difficult
geologic task.  Many active faults are complex, consisting of multiple breaks,
yet the evidence for identifying active fault traces is generally subtle or
obscure.  The distinction between active and long-inactive faults may be
difficult to make.   To assist with this task, the California Division of Mines
and Geology has developed guidelines for detecting and evaluating the hazard
of surface and near-surface fault rupture (California, 1975).

    The general fault zone can be divided into a main fault zone, a branch
fault zone, and a secondary fault zone.  The main fault zone contains the main
fault, i.e., the fault with the greatest displacement or  length, and closely
associated faults.   The width of this zone ranges up to 3,000 ft, but in most
cases is half that width or less.  Faults that diverge from and extend well
beyond the main zone of faults are referred to as branch  faults.  Secondary
faults are completely separate from the main fault, sometimes several hundred
feet to a few miles away.  Often associated with main, branch,  and  secondary
                                     6-24

-------
faults are small, subsurface faults that are evident as fault planes running
parallel to the fault and typically are considered a part of that fault.

    Adjacent to the fault rupture a zone of deformation is commonly found.
This is an area where the ground has been bent or warped as a consequence of
the two surface planes moving against one another.  Surface deformation may
occur within a zone several tens to several hundred feet wide.  Structures
located within this zone are subject to distortion and are likely to be
damaged.
    6.4.2  Regulatory Requirement for Siting Monofills in Fault Areas

    The Agency believes  that monofills may be affected by fault rupture and
 surface deformation resulting  from earthquakes.  To minimize the risk, the
 rule  states  that new  sewage sludge units shall be located 60 m (200 ft) or
 more  from a  fault  displacement from Holocene time.  (The Holocene is a
 geologic  time period,  known as an  epoch, that extends from the end of the
 Pleistocene  to the present and includes approximately the last 11,000 yr) .
 The proposed regulation  should prevent siting on the zone of deformation where
 the ground may be  bent or warped.

    The Agency's proposal reduces  the possibility that landfill slopes would
 be impaired  by fault  rupture,  and  the resulting potential for exposing waste
 to surface runoff.
6.5  SEISMIC IMPACT ZONE

    Another aspect of the effect of earthquakes on monofill siting is the
extent of the seismic impact zone.  Geologic features can contribute
significantly to the  local effects of earthquake shock.  Because seismic waves
travel at different speeds in different materials, the effects of seismic
waves in rock and unconsolidated material will vary  (Legget and Karrow, 1983).
                                      6-25

-------
Larger areas are influenced in the eastern United States than  in  the  western
United States (USGS,  1981).

    Regional seismicity maps have been available since the 1950s  to aid the
engineer in reducing earthquake effects on buildings and other structures.
Regional seismicity or risk maps usually do not attempt to reflect geologic
conditions or take into account variations due to soil properties.  The maps
primarily provide insight into the relative hazard of seismicity  across the
United States together with the relative importance of various parameters
involved (Algermission and Perkins, 1976; and Bolt, 1975).

    The U.S. Geologic Survey published an open-file report addressing the
probabilistic estimate of maximum acceleration in rock in the  contiguous
United States.  The report presents maps of the relative earthquake hazard in
various "seismic zones" based on a constant-probability level.  Maps  provided
with the report identify the maximum horizontal accelerations  in hard rock
expressed as a percentage of the Earth's gravitational pull, g, with  a. 90%
probability that they will not be exceeded in 10, 50, and 250  years
(Algermission and Perkins, 1982).

    A single parameter, such as an estimate of maximum acceleration,  does not
provide all of the information necessary to describe the characteristics of
strong ground motion important in structural design.  Nevertheless, a wide
range of structures can and have been designed to be earthquake resistant
using peak acceleration as the basic ground motion data (Algermission and
Perkins, 1976).
    6.5.1  Impacts of Siting Facilities in Seismic Impact Areas

    Earthquakes can affect a waste management facility through ground motion,
surface faulting,  earthquake-induced ground failures, and tsunamis.  Although
earthquakes cause much less economic loss annually in the United  States  than
do ground failures and floods,  major earthquakes have the potential  to cause
                                     6-26

-------
sudden and great loss.  Ground motion associated with earthquakes can damage a
monofill by causing dikes and berms to fail, resulting in the exposure of
waste and/or rupture of any leachate collection and liner systems.  Runoff
contaminated by contact with exposed waste potentially could contaminate
surface water bodies.

    Failure of natural and manmade slopes adjacent to the monofill may also
affect the facility.  Failure of these slopes may damage runon and runoff
control systems, leachate disposal/management systems, and the stability of
the containment structure berms.  These earthquake effects constitute one
important set of considerations in siting, designing, and constructing these
critical structures  (EPA, 1988a)

    Earthquakes that occur near waste management facilities pose a risk to the
public and the environment because the motion of the ground during destructive
earthquakes has the potential to damage inplant collection and waste-
processing facilities, i.e., landfills with protective engineering design and
long-term surveillance.  The most typical seismic-related damage categories
are:

    •  Failure of  structures, tanks, etc., due to a high level of ground
       motion
    •  Failure of  structures, tanks, impoundments, and landfill containments
       due to soil liquefaction and liquefaction-induced landsliding and/or
       lurching, or, generally, extensive soil settlement, failure of
       structures  and tanks due to fault rupture passing through structures,
       tanks, and  landfills
    •  General landsliding
    •  Failure of  impoundments (dams, embankments, etc.)

    One major cause of destruction during an earthquake is the failure of the
ground structure by loss of strength.  This type of failure typically occurs
in loose,  saturated, cohesionless soils.  This phenomenon, termed
liquefaction,  is a result of an increase in the soil pore water pressure, that
decreases,  and sometimes eliminates, the shear strength of the soil.
                                      6-27

-------
    Bodies of loose, relatively fine-grained uniform sand below  the  water
table are susceptible to liquefaction during an earthquake,  especially if the
duration of the quake is long enough for the occurrence of a large number of
oscillations involving repeated reversals of shearing strains  of large
amplitude.  Soil that has lost all strength behaves like a viscous fluid and
often appears in the form of "sand fountains or boils"  during earthquakes.
When a soil fails in this manner, a structure resting on it  simply sinks
(Prakash, 1981; Terzahgi and Peck, 1967).

    Liquefaction causes three types of ground failure: lateral spreads,  flow
failures, and loss of bearing strength.  Lateral spreads involve the-lateral
movement of large blocks of soil as a result of liquefaction in  a subsurface
layer.  Flow failures consist of liquefied soil or blocks of intact  material
riding on a layer of soil, and are the most catastrophic type  of ground
failure caused by liquefaction.  Loss of bearing strength when the soil
supporting a building or structure liquefies causes large deformations within
the soil that allow the structure to settle and tip (USGS, 1981).
    6.5.2  Regulatory Requirement for Siting Monofills in Seismic Impact Areas

    The Agency believes that monofills may be affected by  ground  motion
resulting from an earthquake.  To minimize the risk, all new monofill  units
located within a "seismic zone" defined' as having a 10% probability of maximum
horizontal acceleration in hard rock exceeding 0.10 g in 250 years  must design
all containment structures, including liners, leachate collection systems, and
surface water control systems, to resist the maximum horizontal acceleration
for the zone.

    This requirement also applies to a seismic zone with a 4%  probability of
exceeding the maximum horizontal acceleration in 100 years.  The  Agency
believes that the areas affected by the seismic zone requirement  represent the
areas of the United States with the greatest seismic risk.   In addition,  the
                                     6-28

-------
Agency believes that these probabilities and ranges of maximum horizontal
accelerations are acceptable, and that the requirement adequately protects
human health and the environment.

    EPA has included this restriction as a performance requirement for
monofills to minimize the risk of slope and liner failure due to seismic
activity.  By minimizing the risk failure of the landfill slopes, the
requirement also reduces the potential for exposure of sewage sludge to the
atmosphere and the possible contamination of runoff by contacting exposed
sewage sludge.

    In addition, the Agency requires that no new monofill units shall be
located  in areas where  support for  the structural components is inadequate.
The Agency considers soils with  the potential for liquefaction as areas of
inadequate support.  An owner or operator must determine if the proposed
monofill site is susceptible to  liquefaction.  If it is, and protective
measures cannot be incorporated  into the design, then the Agency will consider
the site unstable.  Unstable areas  are further discussed in Section 6.6 of
this  document.
     6.53  Methods for Determining Seismic Risk

     Numerous seismic  design methods are  available to the owner or operator to
assess the proposed design of the monofill and appurtenances.  The two most
commonly used include the seismic coefficient method and the permanent
displacement method.  Both methods have  been used to evaluate the design of
embankments under seismic loading conditions.

     The seismic coefficient method utilizes a static, horizontal inertial
force applied to a potential sliding mass in an otherwise conventional static
limit analysis.   This method, commonly referred to as a conventional static
stability analysis, represents earthquake loading by a statically applied
horizontal force.  The seismic force is  proportional to the weight of the
                                    6-29

-------
potential sliding mass multiplied by the seismic coefficient, which is some
fraction of the acceleration of gravity (Lambe and Whitman, 1969; Hynes-
Griffin and Franklin, 1984).

    The permanent displacement analysis estimates permanent displacement in an
embankment due to seismic loading, as discussed by Newmark in his 1965 Rankin
Lectures.  A principle parameter in the analysis is the peak bedrock
acceleration determined by a site-specific risk assessment.  Using this
method, the motions of a system consisting of a rigid block sliding on an
inclined plane are analyzed.   If the base inclined plane is subjected to some
sequence of acceleration pulses (the peak bedrock acceleration) large enough
to induce sliding of the block, the block will come to rest at some displaced
position down the slope.  An embankment response analysis of the containment
structure must then be performed.   This dynamic analysis requires shear wave
velocities and damping values, consistent with expected strain levels, for all
materials comprising the structure (Hynes-Griffen and Franklin, 1984).

    The Department of the Army Waterways Experiment Station published a
miscellaneous paper outlining the  procedures for performing a permanent
displacement analysis.  The paper  presents figures and tables to assist in the
analysis, as well as to indicate situations where the procedure is not
applicable (Hynes-Griffen and Franklin,  1984).
6.6 SITING REQUIREMENTS FOR UNSTABLE AREAS

    EPA has chosen to ban the siting of monofills in areas that are determined
to be geologically unstable.   These include landslide-prone regions, areas
with comprehensive or expansive soils or ultra-sensitive (quick) clays,  and
subsidence-prone areas,  including karst terrains.
                                     6-30

-------
    6.6.1 Types of Unstable Areas

    6.6.1.1  Landslide Prone Areas

    Landslide is a general term covering a wide variety of mass-movement  land
forms and processes involving the downslope transport of soil and rock
material under gravitational influence.  Landslides are a significant hazard
in virtually every State, and often take place in conjunction with other
hazards such as earthquakes, floods, and volcanoes (USGS,  1981).  They occur
when earth materials fail under shear stress, and can be triggered by any
human activity or natural event that increases shear stress or lowers shear
strength.  The major causes of landslides are (Winterkorn and Hsai-Yang,
1975):

     •   Construction operations or erosion
     a   Earthquakes  and vibrations
     •   Rains or melting  snow
     •   Freezing and thawing
     •   Dry spells
     •   Seepage from manmade sources of water

     Construction operations or erosion can cause a landslide if they affect
the  support of a slope.  Slides are common in excavated cuts for highways and
railways and also in quarries and pits.  Similarly, erosion of the toe
(bottom) of a slope can  leave the remaining slope face unsupported and subject
to sliding.  Heavy buildings located close to the edge of a slope can also
initiate a slide.

    Earthquakes and vibrations from blasting or construction-related
operations can cause spontaneous liquefaction of loose sand, silt, or loess
deposits situated below  the groundwater table.  Under similar circumstances,
                                     6-31

-------
some sensitive clays can undergo a decrease in shear strength.   If pore
pressures increase to the point of total overburden pressure,  the  shear
strength of the soil is drastically reduced, causing the soil  to flow downhill
like a heavy liquid.

    Extremes of temperature and precipitation can contribute to  landslides.
Rains or melting snows can cause increased pore water pressures  leading to
reduced shear strengths along potential slip faces.  Most landslides  occur
after heavy rains or during spring snow melts when large quantities of water
can penetrate cracks and fissures.  Freezing or thawing can induce cracking in
rock formations that result in rockslides.  In silty soils, the  freeze-thaw
cycle can increase pore pressures and, consequently, ground surface movements.
Drying also may result in crack formations that reduce the soil's  shear
strength, thereby increasing the chance of slides.
    6.6.1.2 Expansive Soils

    Certain types of soils and soft rocks will expand when  they become wet and
shrink when they dry out.  Expansive soils are generally rich  in  clay
minerals, which swell by adsorbing water that enters and expands  the spaces
between the mineral's crystalline structures.  Upon drying,  the spacing
decreases and the clay shrinks.  The amount of expansion that  can occur
depends on the type and quantity of clay mineral present, and  is  a function of
time, weight of material resting on top of the expansive clay  (confining
load), initial density, and initial water content (Department  of  Interior,
1974).  Montmorillonite clays are the most prone to swelling with bentonite
clay an extreme case that can increase in volume by a factor of 10 from its
dry to its saturated state.

    Expansive soils are widely distributed worldwide.  Montmorillonites are
most abundant in geological formations throughout the Rocky Mountains,  in the
upper Great Plains, in the southern gulf coast plain, and along the Pacific
                                     6-32

-------
coast.  They are also locally abundant throughout the Great Basin region, and
along the Atlantic coast.

    The extent of damage causd by expansive soils to houses, commercial
buildings, streets, buried utilities, and other structures was estimated at
$7 billion in 1980.  Expansive clay formations that do not exhibit natural
excessive shrink-swell activity can become a problem as a result of
construction activities that reduce confining load or increase water access.
    6.6.1.3 Subsidence Areas

    Subsidence  is  defined  as  the  lowering or collapse of the  land  surface
 either  locally  or  over broad  regional areas (USGS, 1981).  Subsidence  can be
 the result of either  natural  phenomena or human activities.

    Natural  causes of subsidence  include disolution of  limestone and other
 soluble materials,  earthquakes, and volcanic activity.  Limestone  and  dolomite
 are slightly soluble  in water and, especially  in hot and wet  climates,
 excessive moisture can cause  voids to form in  their mineral formations.  If
 overlying materials collapse  or subside into the solution cavities, a  surface
 depression called  a sinkhole  will form.  Where limestone or dolomite deposits
 are widespread  and sinkholes  are  common, the land surface is  referred  to as
 karst topography or karst  terrains after a district in  Yugoslavia  where the
 phenomenon is common  (Bolt, 1975).

    Sinkholes vary in depth from  slight indentations to depressions over 100-
 ft deep.  Typically,  depths range from 10-30 ft with areas ranging from a few
 square  yards to several acres.  There are two major classes of sinkholes:
 those forming from the collapse of an underground void, and the more common
 type,  the doline,  that develops slowly by the downward  solution of the
 underlying rock.   Surface  water entering the first type of sinkhole tends to
 flow rapidly underground through  outlets called swallow holes.  Runoff
 draining  into a doline, however,  usually percolates slowly underground through
                                     6-33

-------
the soil in the bottom of the sinkhole.  If a sinkhole becomes clogged,  a
temporary pond or lake will form; if the outlet is unplugged, rapid  drainage
may occur.  This phenomenon occurred at Lake Jackson, a lake of approximately
25 square kilometers near Tallahassee, Florida, that drained on May  22,  1982.

    Karst terrains and caverns in the United States are found primarily  in
parts of many southeastern and midwestern States.  Sinkholes are found in some
western and northeastern States and in Alabama, where soluble limestone  and
other rocks present in nearly half of the State have created thousands of
sinkholes that pose serious problems for highways and construction.

    Earthquake-related subsidence has taken place mainly in Alaska,
California, and Hawaii, and to a lesser extent in other States.  This type of
subsidence results from the vertical movement of faults and may effect broad
areas.  In 1964 in southern Alaska,  in conjunction with the Prince William
Sound, Alaska, earthquake, more than 70,000 square miles tilted downward more
than 3 ft and subsequently flooded.   Subsidence resulting from intense
earthquake groundshaking involves somewhat smaller areas than that resulting
from regional vertical faulting.   Intense groundshaking generated during
earthquakes in 1811-1812 in New Madrid, Missouri, caused subsurface  sand and
water to be ejected to the surface.   This ejection left voids in the
subsurface, causing local compaction of subsurface materials and settling of
the ground.

    Volcanic-related subsidence is a potential problem in parts of Alaska,
California, Hawaii, Oregon, and Washington.  Subsidence usually is caused by
local collapses above shallow tunnels formed by lava flows. Collapses over
much broader areas also can occur as magma chambers are emptied by volcanic
eruptions (USGS,  1981).

    Human activities that cause subsidence include the withdrawal of water,
oil,  or gas from the pore spaces  in subsurface formations.  When these fluids
are removed by pumping, the effective stress on the formation increases as the
                                     6-34

-------
pore pressure decreases.  This stress can cause the formation to compress
vertically, resulting in land-surface subsidence.

    The most dramatic examples of subsidence caused by withdrawal of oil, gas,
and water are along the Gulf Coast of Texas, in Arizona, and in California.
The harbor at Long Beach, California, has subsided as much as 27 ft from
withdrawal of gas and oil.  The Houston-Galveston area of Texas has
experienced as much as 7.5 ft of subsidence locally and an area of about 2,500
square miles has subsided 1 ft or more. Subsidence in the Houston-Galveston
area appears to have been caused mainly by the withdrawal of large amounts of
ground water, although some areas of local subsidence have been caused by the
extraction of gas and oil.  Coastal towns in Texas, such as Baytown and
Seabrook, have subsided about 3 ft and are now susceptible to flooding from
storm surges and hurricanes  (USGS, 1981).

    Recent research suggests that subsidence caused by withdrawing ground
water can cause fissuring (the formation of open cracks) or renewal of surface
movement  in some areas cut by pre-existing faults.  Surface faulting and
fissuring associated with withdrawal of ground water are believed to have
taken place or to be potential problems in the vicinity of Las Vegas, Nevada,
as  well as in parts of Arizona, California, Texas, and New Mexico (USGS,
1981) .

    The removal of solid materials from underground deposits can also result
in  subsidence.  Subsidence has occurred in shallow coal mines where a lack of
adequate  roof support caused collapses either during mining or long after
mining had ceased.  Subsidence in areas of underground mining has caused
hazardous conditions in parts of Pennsylvania and other Appalachian States,
Colorado, North Dakota, Wyoming, New Mexico, Washington, Iowa, and Illinois.
Subsidence-related damage to surface structures is common in the area around
Pittsburgh, Pennsylvania, where coal has been mined extensively.  Subsidence
depressions and pits forming above abandoned underground mines are a hazard in
the Sheridan,  Wyoming, area.
                                      6-35

-------
    Solution mining also can cause subsidence.  When water-soluble minerals
such as salt, gypsum,  and potash are dissolved and pumped to the surface  so
that the water can be evaporated, huge underground cavities are formed.
Examples of subsidence that are not well known, include the sudden collapse in
1976 of a Grand Saline, Texas street into an abandoned salt mine cavity
created between 1924 and 1949; subsidence in 1974 near Hutchinson, Kansas; and
subsidence in 1971 near Detroit, Michigan (USGS,  1981).

    The addition of water to some soils and soft rock formations can cause
subsidence.  One type of formation where this can happen is called loess.
Loess has the characteristics of soft rock,  being formed from fine-grained
material cemented together in an extremely loose, open structure by a water-
soluble mineral cement.  In the dry state, loess is firm and hard and serves
well as a foundation material.  When subjected to excessive wetting from
sprinkling or ponding on the surface, however, the mineral cement dissolves
and the soil structure collapses in the saturated area.

    Hydrocompaction, or the settling of sediments after water is added, is
another significant cause of subsidence, especially in the arid to semiarid
western and midwestern States.  The areas of known compaction include the San
Joaquin Valley, California; Heart Mountain-Chapman Beach and Riverton, Wyoming
areas; Hysham, Montana; Columbia Basin, Washington; Denver, Colorado;
Washington-Hurricane area in southwest Utah and central Utah; and the Missouri
River Basin.  Hydrocompaction takes place when dry surface or subsurface
deposits are wet extensively for the first time since their deposition as, for
example, when arid land is irrigated for crop production or an irrigation
canal is built on loose uncompacted sediments.  Wetting causes a reduction in
the cohesion between sediment grains, allowing the grains to fill in the
naturally occurring intergranular openings.   Hydrocompaction usually results
in a lowering of the land surface from 3-6 ft, although subsidence of as much
as 15 ft has been recorded.  The effects of hydrocompaction are usually
uneven, causing depressions, cracks, and wavy surfaces that can seriously
damage canals, highways, pipelines, buildings, and other structures  (USGS,
1981).
                                    6-36

-------
    6.6.2  Impacts of Siting Facilities in Unstable Areas

    In landslide-prone areas, construction of monofills on natural slopes can
cause problems if the shear strength of underlying materials is exceeded by
the placement of waste overburden.  Vibrations generated by construction
equipment and heavy vehicular traffic on the site could also trigger ground
movement.  During liner construction, care must be taken not to remove the toe
of adjacent slopes that could slide into the monofill.

    In areas with expansive clay,  liners can be torn or rocked and sidewalls
can collapse if uneven expansion  occurs below the monofill.  To avoid this
situation, expansive soils can be  treated in situ, removed from the site, or
sealed to prevent changes in their moisture content.  If expansive clay soils
are deep  enough, sufficient overburden can be left in place to prevent
excessive swelling.  Regardless of the solution, problems must be recognized
early in  the planning stage in order to include proper expansive soil control
measures  in the facility design.

    In areas that are plagued with subsidence problems due to underground
cavities, there is always a possibility of subsidence occurring below a
monofill.  This is a particular hazard if the weight of the placed waste
exceeds the bearing strength of the materials supporting the facility.

    The Agency examined case studies and documented events that cited the
types of environmental problems resulting from locating waste management units
in unstable areas.   Differential or total foundation movement, loss of
facility structural integrity,  sudden and/or emergency release of
contaminants,  difficult and costly corrective actions, and contaminant
releases attributed to maintenance or inadequate facility design are all
hazards of locating monofills in unstable areas.  The Agency believes that it
is essential for the owner or operator to evaluate extensively the adequacy of
subsurface foundation support before constructing a monofill.
                                     6-37

-------
    6.63 Alternatives

    The Agency considered three alternative approaches for regulating  the
siting of monofills in unstable areas:

    1)  Provide no  standard relating  to  the  siting  of  monofills in unstable
        areas.
    2)  Develop detailed maps of all  unstable  areas and prohibit siting of
        monofills in those areas.
    3)  Require demonstrations  by  all owners/operators that a site is not
        subject to  damage from  unstable  conditions.

    The first alternative was the simplest and least costly  to  implement;
however, it was the least protective of the environment and  human health.

    The second alternative,  to map all unstable areas and ban monofills  from
these areas, was clearly unworkable.   Many unstable areas cover  large
geographic regions and to ban monofills within these areas would impose  a
great economic burden on communities located in those areas.  Additionally the
task of mapping all unstable areas with sufficient detail and accuracy
probably is beyond the capabilities of modern geoscience, as well as too
costly to receive serious consideration.

    The third alternative provides the best approach to controlling  the  siting
of monofills.  Owners/operators would be required  to perform geotechnical
studies of all proposed sites in order to demonstrate that unstable  conditions
do not exist.  This method allows the placement of facilities within broad
geographic areas where unstable conditions may potentially exist while at  the
same time prohibits the placement of a facility on a specific site where
unstable conditions actually do exist.
                                     6-38

-------
    6.6.4  Regulatory Requirement for Siting Monofills in Unstable Areas

    The proposed standard requires that sewage sludge units be located  in
areas where adequate support for the structural components of the units  exist.
Although unstable support conditions may be common over large areas of  the
country, there may be places within these regions where monofills can be
safely sited.

    For the most part, identification of monofill sites in unstable areas must
be on a case-by-case basis because these areas have not been delineated  on a
national  scale.  National maps are available describing karst terrains  and
landslide-susceptible areas, but weak and unstable soils and subsidence-prone
areas appear to be mapped only individually or at the local level.

    Under the proposed requirement, the facility owner or operator must
determine if an area  is  subject to events that may cause or contribute  to the
facility's  failure.   If  the unit is located in an unstable area, the owner or
operator  must demonstrate to the State that the proposed site is not subject
to destabilizing events.
                                     6-39

-------
                               SECTION SEVEN
                         MANAGEMENT PRACTICES
    Six areas of management practice requirements  are  specified by the
proposed sewage sludge regulations.   One  of these  six, pathogen reduction, is
covered under separate title (EPA,  1989).   The  remaining  five  -- landfill
cover requirements, disease vector  controls,  explosive gases controls, access
controls,  and runon/runoff controls - -  are  discussed in this section of the
technical support document for monofills.   These management practices are
required under Subtitle D or C of the Resource  Conservation and Recovery Act
(RCRA) and have been incorporated to some extent into  the proposed sewage
sludge regulation.  The way in which the  requirements  have been incorporated
and the rationale for the approach used to  incorporate or specify alternatives
to these requirements are presented below for each of  the five management
practices covered in this document.
7.1 LANDFILL COVER REQUIREMENTS

    7.1.1  Landfill Cover

    The preamble to the current Subtitle D Criteria  (44  FR  53456, September
13, 1979) states that the daily application of soils  or  other  suitable cover
materials at monofills serves the following functions:

    •  Controls the escape of odors,  litter,  and air  emissions
    •  Reduces the potential for fires
    •  Reduces rain water infiltration,  thereby decreasing  leachate  generation
       and surface and ground-water contamination
    •  Improves the facility's appearance and enhances utilization after
       completion

                                     7-1

-------
    •  Controls onsite populations of disease vectors
    •  Discourages scavenging

    The requirement to apply daily cover to monofills specifies  that  "sewage
sludge used or disposed of in a sewage sludge unit shall be covered with  cover
materials at the end of each operating day, or at more frequent  intervals if
necessary, to control disease vectors, odors, gas venting, and scavenging."
EPA is proposing this requirement for landfill cover because the problems
named above are alleviated in part by cover material.  In addition, 19  States
and Territories have some requirement for daily, intermediate, or  final cover,
suggesting that this procedure is effective.
     7.1.2  Depth of Cover

    The Subtitle D Criteria do not specify a required cover depth.   It  is
suggested that 6 inches of compacted earthen material be applied at  the end of
each operating day.   The use of earthen material is a standard practice at
most monofills and it is widely accepted that a minimum of 6 inches  of
compacted soil will control disease vectors and moisture infiltration.
Nonearthen materials, however, may also meet the requirement and provide the
same protection as earthen material.
     7.13  Characteristics of Cover Material

    EPA has chosen to make its requirements for daily cover broad, allowing
the States the flexibility to require more-specific practices.  Daily cover
requirements that EPA does not address in the rule include daily grading to
control erosion and ponding,  and stockpiling fill at the landfill  site to last
for a certain period of operation.  EPA is allowing the States  to  specify
these requirements if they choose.
                                      7-2

-------
7.2  DISEASE VECTOR CONTROL REQUIREMENTS

    Monofills can provide food, shelter, and breeding areas for disease
vectors, which are animals such as rats, flies, and mosquitoes that can
transmit disease to humans.  Some diseases associated with these vectors are
rat-bite fever, leptospirosis,  plague, salmonellosis,  trichinosis,
murine/typhus fever, malaria, and yellow fever (Noble, 1976;  EPA, 1979)
Because monofills can provide an environment for a large number of disease
vectors, EPA requires that owners or operators conscientiously monitor the
disease vector population and follow practices to minimize that population.
EPA further  requires monofill owners or operators to employ prevention and
control techniques because accurately measuring specific levels of disease
vectors would be difficult or impossible.

    When cover material  does not control disease vectors sufficiently,
judiciously  applied poisons  (insecticides and rodenticides) are an effective
control measure.  Insecticide sprays can be used to control fly and mosquito
populations, and rodenticides can be used to control rats.  Rodenticides,
however, serve strictly  as short-term solutions when the amount of daily cover
is insufficient to prevent rats from flourishing at the monofill.  It should
be noted that insecticides or rodenticides must be used according to label
instructions to avoid adverse environmental impacts.

    Predatory or reproductive controls can help minimize the vector
population.  For example, organisms that feed on mosquito larvae could be
introduced to the facility.  Agitating and/or varying the level of standing
water (e.g., leachate ditches)  also helps prevent mosquito reproduction. (EPA,
1980) .
                                      7-3

-------
7.3  REQUIREMENTS FOR CONTROL OF EXPLOSIVE GASES

    When organic matter in monofills is decomposed by anaerobic bacteria,
explosive gases, predominantly methane, are produced.  Anaerobic conditions
arise when the conditions in the voids within the waste materials change from
aerobic to anaerobic and the chemically available oxygen in the refuse is
consumed.  The process of gas production is controlled by site-specific
conditions that affect the bacterial population,  such as pH,  temperature,
moisture, and oxygen content (both gaseous and chemically available).   As
landfill gas is generated,  pressure builds up within the material.   The
pressure then forces the gas to migrate laterally and/or vent to the
atmosphere.  The two basic mechanisms by which gases migrate  are molecular
diffusion, which is slow, and convective mass transfer,  or pressure-induced
flow, which is the predominant mechanism of subsurface gas flow. (GCA, 1986c).

    The methane component of monofill gas can create an explosion hazard.
Migrating methane has forced the evacuation of residences and businesses,  and
has been responsible for onsite and offsite fires,  explosions,  property
damage, human injury, and in some cases,  death (GCA, 1986c).   In addition  to
property damage, groundwater contamination and vegetative destruction on site
and on adjacent lands have resulted from landfill gas migration (EPA,  1977a).

    For these reasons, EPA established an explosive gas criterion in the
original Subtitle D Criteria under 40 CFR 257.3-8(a) that sets limits  on
explosive gases (methane) in facility structures  and at the property
boundaries.  This standard requires that concentrations of methane not exceed
the lower explosive level (LEL) (5% methane) in soil at the property boundary
and 25% of the LEL (1.25% methane) in onsite structures.  Because the human
health standard for methane is greater than the LEL, EPA believes the current
limits provide adequate protection to human health and the environment at  the
property boundary and allow for a margin of safety for onsite structures.   In
selecting the 25% figure, EPA is using a safety factor recognized as
appropriate for similar structures by other Federal agencies, e.g., in
                                     7-4

-------
regulations established by the Occupational Safety and Health Administration
and the National Fire Protection Codes.

    The final method selected to prevent or control the formation and
migration of monofill gases will depend on site-specific conditions, including
soil type, geology, hydrology, and climatic conditions.  Numerous methods that
have been used to control gas migration include (EPA, 1977; Raymond Vail and
Associates, 1979):

    •  Permeable  trench  (gravel trench)
    •  Semipermeable barrier  (synthetic liner or clay liner) used with a
       gravel trench (trench barrier system)
    •  Venting system with gravel trench or gravel layers  (passive landfill
       control systems)
    •  Venting with a gas pumping system (active landfill vent control
       systems)

A report  prepared by Raymond Vail and Associates (1979) provides more detail
on the gas migration control  systems discussed above.

    A permeable  trench that collects and vents the gas is placed at the
perimeter of a. site where gas migration is of most concern.  The trench
generally is installed at a depth equal to the depth of the site, but this
approach  is not  the best approach, because gas may migrate under the trench.
Ideally the trench should be  installed to ground water depth or to the depth
of an impermeable geological barrier.  The permeable-trench method of venting,
however, has had  a low percentage of success in controlling gas migration
(EPA, 1977a; Raymond Vail and Associates, 1979).

    The second method, a gravel trench used with a semipermeable liner (a
trench barrier system), provides a more effective barrier than the permeable
trench system.   The trench-barrier system should be installed to water table
depth and care must be taken during installation of the liner material to
avoid tears (EPA, 1977a; Raymond Vail and Associates, 1979).
                                      7-5

-------
    The third method,  a pipe venting system used with a gravel trench (a
passive landfill vent control system),  has approximately the same
effectiveness for controlling gas migration as trenches used alone.  In
addition, this system is more costly than the above two methods and may be
subject to vandalism (EPA,  1977).

    The last method, the pumping system or active landfill vent control
system, provides the greatest effectiveness for gas migration control but is
more costly to install and maintain.  This system incorporates a series of
wells  (not necessarily installed to the water table) that withdraw the gas
from the landfill or from the area surrounding the landfill.   Generally,  if
recovered gas is to be used as an energy source,  an active vent system is
used.  With this method, recovery and migration control are accomplished in a
single process.   Where gas migration is to be controlled,  pumping wells are
installed between the source of the gas and the threatened building or home.
To avoid continuous operation, systems  may be designed to operate only when a
certain concentration of methane is detected (EPA,  1977).
7.4  ACCESS CONTROL REQUIREMENTS

    Controlling access to monofills is  necessary to prevent injury to the
public from landfill hazards and to ensure that all wastes are properly
disposed.  Some sources  of potential injury at landfills are (EPA,  1980):

    •  Operations involving heavy equipment and haul vehicles
    •  Waste related hazards;  such as pathogens
    •  Accidental or intentional fires
    •  Excavations and other earth moving activities

    The potential harm that these hazards pose to facility personnel can be
controlled through proper training, use of safety equipment, and other
                                      7-6

-------
procedures (44 FR 53460, 1979).  These controls,  however,  cannot be imposed on
the general public.  The only way to prevent potential harm to the public is
by prohibiting access to monofills by the general public and by strictly
controlling users of the facility on the site (44 FR 53460, 1979).

    Control of authorized persons at monofill sites can be achieved using any
of the following measures (EPA, 1980):

    •  Supervising the  unloading area
    •  Providing adequate lighting
    •  Posting information and direction signs
    •  Prohibiting scavenging


 7.5 RUNON/RUNOFF CONTROL REQUIREMENTS

    To minimize  liquids entering the  monofill waste, runon of liquids from
 surrounding  areas  onto  the active area of the unit must be controlled.
 Furthermore,  runoff  of  liquids from active portions of a unit must be
 controlled,  because  of  the danger that the runoff will contaminate surface
 water.

    The  introduction of liquids is a  concern for all phases of monofill
 operation; however,  the active portion of monofills is of primary concern,
 because  the  irregular fill contours promote waste exposure and infiltration of
 fluid into the waste.   Other areas of monofill operations have been closed,
 covered,  and  planted with vegetation, thereby immobilizing or diverting any
water near the surface.
                                     7-7

-------
    7.5.1  Runon

    Two methods of minimizing runon onto the active portion of a monofill are:
(1) making the active portion relatively impervious to water  (Lutton,  1982;
McAneny, 1985) and (2) diverting the water away from the active area  (Weiss,
1974).   The first method is impractical because it requires measures
comparable to those used for permanent closure.  Furthermore, because  of
relatively rapid changes in the active area, the method could not be
implemented quickly enough to be effective.  The second method, runon
diversion, is accomplished either by using natural contours or by constructing
conveyances designed for the amount of water and potential damage associated
with a particular storm event (e.g., 25-year or 50-year storms).

    Because storms vary in intensity and duration, a diversion system  may be
underdesigned (resulting in inadequate control) or overdesigned (resulting in
unnecessary and costly controls).   To contend with the variability of  storm
events, EPA has chosen as the design parameter for runon control the peak
discharge of a storm whose intensity and duration is likely to occur once
every 25 years.  The Agency has adopted this approach for consistency  with the
40 CFR Part 264 standards that require active portions of a hazardous  waste
landfill to be protected from the peak discharge of a 25-year storm.
    7.5.2  Runoff

    Although runon controls protect the active portions of monofills  from most
water, they do not prevent the introduction of direct rainfall.   Since runoff
produced by rain falling directly on the active portions could be
contaminated, it must not be allowed to leave the site unless applicable
provisions of the Clean Water Act (CWA) are met.  These provisions, as
specified in existing regulations, prohibit discharge that violates §402 of
the CWA and nonpoint source pollution that violates a water quality management
plan under §208 of the CWA.
                                      7-8

-------
    EPA has chosen the peak discharge of a 25-year storm as the design
parameter for runoff control for the same reasons this parameter was chosen
for runon control.  For runoff control, however, both the water in contact
with sludge in the active area and the uncontaminated runoff, must be
collected.  The volume of rain falling during a 24-hour period is usually the
measure used in stormwater management design for small watersheds of less than
2,000 acres (SCS, 1985; Viessman et al.,  1977).  This 24-hour period is an
average that includes short storms of high intensity and long storms of low
intensity.
                                      7-9

-------
         APPENDIX A
    Partitioning of Pollutants
Between Sludge Solids and Water

-------
                    PARTITIONING OF POLLUTANTS
                 BETWEEN SLUDGE SOLIDS AND WATER
Background

     The partition coefficient  (or distribution coefficient) is
the quotient of the concentration (e.g., mg/kg) of a specific
pollutant sorbed to solid particles, and the concentration  (e.g.,
mg/L) dissolved in the  liquid.  The leaching mobility of a
pollutant is inversely  related  to its partition coefficient.

     The value of the partition coefficient depends on the
properties of both the  chemical being sorbed and the particles
onto or into which the  chemical is being sorbed.  Typically, the
partition coefficient is measured by (a) equilibrating the
chemical and the particles together in  a well mixed aqueous
slurry,  (b) measuring the total concentration of chemical in the
slurry,  (c) separating  the aqueous and  particulate phases by
centrifugation,  (d) measuring the chemical concentrations in the
supernatant, equating this to the dissolved concentration, and
finally  (e) calculating the  sorbed concentration by difference.

     The estimation of  an appropriate value for a pollutant's
partition coefficient is made difficult by the confounding
influence of the particle concentration.  Considerable data
indicate that in systems undergoing agitation, the partition
coefficient tends to decrease with increases in the particle
concentration (as noted by DiToro 1985  and by others).  Figure 1
illustrates a typical relationship between the measured partition
coefficient and the particle concentration.  Both metals and
organics tend to display the illustrated behavior (DiToro et al.
1986).

     As shown in Figure 1 for hexachlorobenzene, the partition
coefficient is approximately inversely  proportional to the
stirred particle concentration, within  the range measured.
Explanations for this behavior  generally fall into two groups.
The first attributes the behavior to the confounding influence of
a third phase of nonsettlable sorbing material (for example,
micro-particles, as suggested by Gschwend and Wu 1985).   While
the simplicity of this  explanation is attractive, it does not fit
all the data,  failing particularly in experiments designed to
discern the existence of a third phase  (DiToro 1985).   The second
group postulates a desorption reaction  induced by particle
interactions (DiToro 1985,  Mackay and Powers 1987).   While this
explanation better fits the data,  the molecular basis for it is
speculative.

     While the inverse dependency of partition coefficient on
particle concentration is observed using the standard laboratory
protocols involving agitated slurries,   it is not observed where
the chemical is equilibrated with the particles in a quiescent


                               B-l

-------
          0 -
         60-
     D
     O
         50-
         40-
         3 5
                                             Stationary Sol ids  O
                            St irred Sol ids
                             Log mg/L So Ii ds
  Figure  1:     Relationship between Hexachlorobenzene  Partition
                Coefficient (Koc,  L/kg organic carbon)  and Solids
                Concentration.   (Data from DiToro  et al.  1985)


 medium (DiToro  et al.  1985).   In the absence of particle agita-
 tion,  the partition coefficient  takes on  a the value  appropriate
 for  a  low solids  medium,  as shown in Figure 1.  Thus,  an agitated
 leaching  test such as  the TCLP might often be expected to indi-
 cate greater mobility  than a stationary leaching  test  such as  the
 column method (Appendices A and  B,  respectively,  of EPA 1986).

     Given the  confounding influence of particle  concentration on
 the partition coefficient measured in standard laboratory
 protocols,  accurate estimation of a partition coefficient
 appropriate for sludge-borne pollutants in soil or buried sludge
 is not  an easy  task.   The degree of dependence on particle
 concentration varies somewhat from pollutant to pollutant,  and
 only occurs within a certain range of particle concentrations
 (DiToro 1985).  Consequently, while it is expected that the
 degree of  sorption actually occurring in  soil or  buried sludge
 (stationary particles) would be  greater than measured  by
 laboratory protocols using stirred particles, the magnitude of
 the difference  cannot  be  predicted with confidence.   In the
 subsequent discussion, stirred-particle partition coefficients
will be treated as  good estimates  of actual  partition
coefficients occurring after burial,  recognizing  that  this may
err on the side of  safety.
                                B-2

-------
 Measured  Partition  Coefficients  for  Metals

      For  calculating  national  criteria  for  metals,  values
 measured  by  Gerritse  et  al.  (1982) were used  for  the  partition
 coefficients in  the soil underlying  a monofill  (but not  in  the
 sludge  within the monofill).   In a series of  measurements
 Gerritse  et  al.  determined  the partitioning of  several metals
 between a number of solid and  liquid phases.  The solid  phases
 consisted of either (a)  a sandy  soil, having  pH 4.5 - 5.0,  no
 clay, and 3.5 percent total  organic  matter, (b) a sandy  loam,
 having  pH 7.5 -  8.0,  20  percent  clay, and 2.5 percent organic
 matter, or (c) digested  sludge particles (60  percent  organic
 matter),  obtained from two  treatment works, both  in an aerobic
 condition with pH 5-6,  and an  anaerobic condition with pH 7 -
 7.7.  The liquid phases  consisted of (a) dilute inorganic
 solutions, or (b) sludge liquid  supernatant.  During
 equilibration, the  particle  concentrations  were 160,000  mg/L for
 the soils and 20.000  mg/L for  the sludges.

      U.S. EPA (1985), in generating  the environmental profiles,
 presented the geometric  mean of  the  range of  Gerritse values for
 partitioning between  sand or sand loam  and  sludge liquid
 supernatant.  These partition  coefficients  are  presented in
 Table 1.   Corresponding  values for partitioning between  sludge
 solids  and sludge liquid are also shown in  Table  1.


 Table 1:   Partition coefficients for sludge liquid  coupled  with
           aerobic and anaerobic  sludge  (Gerritse  et al.  1982),
           and two soils  (U.S.  EPA 1985  interpretation of Gerritse
           et al. 1982 graphs).

 Solid Matrix    Arsenic   Cadmium Copper   Lead  Mercury   Nickel

 Anaerobic Sludge   -      59,000   120,000   73,000     -      600
 Aerobic Sludge     -      1,500    4,200   62,000     -      270
 Sandy Loam       19         430       92      600    320      59
 Sandy Soil         5.9       15       42      230    580      12
     Gerritse et al.  (1982) presented the values for sand and
sandy loam graphically; values estimated from the graphs appear
to be subject to roughly a 10 percent uncertainty.  While U.S.
EPA (1985) reported three significant digits, the third has no
significance and is not displayed above.

     Three features may be noted from the above tabulated values.
First,  most of these metals had greater affinity for sandy loam
(with its higher pH and clay content) than sandy soil.  Second,
all the metals appear to have greater affinity for sludge than
the two tested soils,  although the lesser particle concentration
Gerritse et al.  used in the sludge (20,000 mg/L) compared to the


                               B-3

-------
soils  (160,000 mg/L) may contribute  to  this  result.   Third,  most
metals are sorbed more  strongly under anaerobic  conditions  than
under  aerobic conditions.

     In order to supplement the Gerritse et  al.  (1982) data for
partitioning within sludge, the data of the  40-City  Study  (Burns
and Roe 1982) were examined.  The 40-City  Study  was  intended to
provide information on  the fate of priority  pollutants in  sewage
treatment plants.  In this study, pollutant  concentrations  and
solids concentrations were measured  in  the sludge  and effluent.
Such data is sufficient to calculate a  partition coefficient
between sludge solids and wastewater, as they undergo equili-
bration in the aeration tank  and secondary clarifier.    From
these  data, a partition coefficient  can be calculated from  the
following formula, the  derivation of which is provided in the
Supplement to this Appendix:

           TT =  (ct2  -  ctl)  / (ctlm2 - c^m,)                 (1)

where  TT denotes  the partition coefficient, ctl and  ct2 the
pollutant concentration in secondary effluent and  sludge
respectively, and ml and m2 the  solids concentrations in
secondary effluent and  sludge respectively.  Note  that TT is
called the distribution coefficient, Kd, in the  main body of this
Technical Support Document.

     Data for four metals, arsenic,  cadmium, lead, and mercury
were evaluated in this  way.   The results  are summarized in
Table  2, where the estimated  median, 10th  percent!le, and 5th
percentile are presented.  In summarizing  these  data  a few  POTWs,
those  with the least contaminated sludge,  were not included.  The
tabulated partition coefficients thus apply  to sludges ranging
from less than typically contaminated to most heavily
contaminated, that is,  those  of greatest regulatory  interest.


Table  2:  Summary of Partition Coefficients  Determined for  All
          but the Least Contaminated Sludges.

             Arsenic          Cadmium            Lead      Mercury
Estimate      >2 ppm      >5  ppm  >30 ppm     >100 ppm   >0.5 ppm

Median         2,400      34,000   53.000      34,000      32,000
10th %ile        170       3,000   19,000        8,900       4,900
5th %ile         120       2,000   13,000        3,300       4,300
     It should be noted that the above partition coefficients are
for raw, not digested sludge.  Nevertheless, in most respects raw
and digested sludge do not differ greatly.  Compared to raw
sludge,  digested sludge is slightly higher in inorganic material,
lower in organic acids,  and higher in pH  (Metcalf and Eddy 1972).


                               B-4

-------
     The Table 2 values are somewhat  lower than field estimates
of partition coefficients for natural sediment particles,
summarized in Delos et al.  (1984).  This difference could stem
the differing compositions of solids.  Alternatively the
difference may be an artifact of the high solids concentrations
in the influent to a secondary clarifier, tending to depress the
partition coefficient.

     In deriving the national numeric limits, only the soil
partition coefficients of Table 1 were used.  None of the sludge
partition coefficients in either Tables 1 or 2 were used.  For
metals, the relationship between the pollutant concentrations in
sludge and in leachate was obtained by a different approach,
described below.
Alternative  Approaches  for Modeling Metals Leachate Generation

      Two  alternative  approaches  for modeling metals partitioning
within  the  sludge  are discussed  below.

      Option  A  (fixed  leachate  concentration):

      The  proposed  national numeric limits for metals were derived
 assuming  that  the  pollutant concentration in the leachate main-
 tains a fixed  value independent  of the pollutant concentration in
 the  sludge.  The partition coefficient was assumed to be zero.
 The  dissolved  or leachate concentration was assumed to be fixed
 at a solubility limit for the  metal.  The particulate metal in
 the  sludge was assumed  to be composed of metal precipitant,
diluted into but not  interacting with the sludge solids.  On a
molecular level, the  implication is that a dissolved metal ion
would interact with like metal ions present at mg/L levels or
less in the  sludge liquid to form a precipitant, but would not
interact  with  the  other sludge solids present at 200,000 mg/L.

      In deriving a pollutant numeric limit using such a
framework, one of  the key input  parameters is the leachate
concentration.  For deriving the national numeric limits for
cadmium,  copper, and  lead, the Agency used a reported maximum
leachate  concentration  (SCS Engineers [undated], as referenced by
EPA  1978).   During development of the proposed regulation, the
original  data  and reference were not examined, and thus the
reliability  of these  leachate data is not known.  For mercury and
nickel,  the  leachate  (dissolved) concentration was set at the a
maximum observed concentration of dissolved plus particulate
metal in POTW effluent.   For arsenic, the leachate concentration
was  set arbitrarily.

     Once the leachate percolates out of the sludge into the
underlying soil,  Option A invokes conventional partitioning
theory to describe pollutant interactions with the soil.


                                B-5

-------
      Option  B  (conventional  partitioning):

      This  option  applies  conventional  partitioning theory to
 determine  the  metals   leachate  concentration in both the  sludge
 and  the underlying  soil.   This  option  was  evaluated too  late  in
 the  regulatory development process  to  be considered for  setting
 the  national numeric  limits  for metals.  It  is,  however,  directly
 parallel to  the approach  used for  setting  the national numeric
 limits for organic  pollutants.

      To illustrate  application  of  this approach,  the partition
 coefficients for  sludge liquid  and  solids, observed by Gerritse
 et al. (1982),  are  used here for cadmium,  copper,  and nickel.
 For  lead,  the  10th  percentile partition coefficient from  the  40-
 City Study is  used  here in place of the Gerritse value,  in order
 to provide greater  safety.   Lastly,  for arsenic and mercury,  for
 which Gerritse did  not report sludge partition coefficients,  the
 10th percentile values from  the 40-City Study are again used.

      The pollutant  concentration in whole  sludge,  denoted cs
 (mg/kg dry wt), and the dissolved pollutant  concentration,  cd
 (mg/L), in the equilibrated  liquid  or  leachate are related by the
 expression:

           ca/cd =[*£,+ (1-fJ/Yj / fs                    (2)

 where IT is the partition  coefficient (L/kg),  fs is the fraction
 of  solids  in the  sludge (equal  to  one  minus  the fraction  liquid),
 and  2TL is  the density of the  leachate  (kg/L)  .  Since the density
 of the leachate is  essentially  1.0,  the above equation simplifies
 to:

           c3/cd =  (TT - 1 + 1/fJ                           (3)

 Thus, for  a  monofilled sludge having 20 percent solids content,
 cs/cd = TT + 4.

      Comparison of  Options:

      The two options  are  compared in Table 3.   The national
 numeric limits  for  these  options were  computed on a personal
 computer using  the  SLUDGEMAN program.   All input  parameters were
 set  at the values specified  in  the  main body of this Technical
 Support Document, except  for the Option B metals  leachate  concen-
 trations,   which were  set  as  described  above.   In  all cases  the
 model was  run  iteratively, modifying the input sludge quality
 before each  successive run,  until the  sludge quality producing
 the maximum  allowable  exposure  (e.g.,  the MCL)  was found  by trial
 and error.

     For Class  1 aquifers  the depth  of the unsaturated zone was
 set at 0.01 m  (effectively zero), and  the distance in the
 saturated  zone  is by default  zero.    Option A consistently
produces  much lower numeric  limits  than Option B.   It should  be


                               B-6

-------
noted that with  essentially  zero  opportunity  for  attenuation of
the peak concentration within  the soil,  the ground  water  concen-
tration calculated by Option A does  not  respond to  increases or
decreases in  the sludge  concentration  until one applies the
additional constraint (from  Equation 3)  that  c,/cd=4 when  TT=O and
the amount of metal precipitant in the sludge is  zero.
Table 3:
Comparison of two options for modeling metal leachate:
(A) fixed leachate concentration, and (B) conventional
partitioning.
               As
              Cd
Cu
Pb
       SLUDGE PARTITION COEFFICIENTS  (L/kg)
 Option A         	      not applicable
 Option B       170     1500      4200      8900
       CLASS
 Option A
 Option B
  1 NUMERIC LIMITS (mg/kg)
   0.44    0.036       18
     19       14    19000
       CLASS 2 NUMERIC  LIMITS  (mg/kg)
 Option A        15        6.5   >10000
 Option B        42        41    >10000
       0.36
        780
                               400
                              1900
                                       4900
     0.0074
        8.6
                  19
                  51
 Ni
                          270
  7
480
              >10000
                2200
      For  Class 2 aquifers the depth of  the unsaturated zone is
 set  at  1.0 m, and the distance  in the saturated zone  set at
 150  m.  For  arsenic, cadmium, lead, and mercury, Option A
 produces  limits around 3-6  fold lower than Option B.  For nickel,
 Option  A  produces a limit at least 5 fold greater than Option B.
 For  copper,  the options are effectively equivalent.

      It might be noted that in  Option A the sludge concentration,
 cs, affects only the leachate pulse time,  which in turn affects
 the  degree of attenuation of the peak concentration that can
 occur primarily due to sorptive detention.  In Option A the
 numeric limit is sensitive  to the absolute magnitude of the
 leachate  concentration, cd.   Option A will generate an infinite
 numeric limit if the user sets  the leachate concentration below
 the health effects concentration.  In Option B, on the other
 hand, the numeric limit is  sensitive to the ratio ca/cd  (i.e.,
 the partition coefficient).

     Technically,  the principal disadvantage of Option A (fixed
 leachate)  is that it is difficult to reconcile with the available
 data (including Gerritse et al.  1982),  and with accepted theory
 (as presented for example by Honeyman and Santschi 1988).
Option A lacks a rationale for  applying conventional partitioning
to organics but not metals in sludge, and for applying
conventional partitioning to metals in  soil but not in sludge.
Option B,  on the other hand, incorporates an accepted approach
                               B-7

-------
and better uses the available data.  Although Option  B  often
produces less stringent  limits than Option A, the use of
partition coefficients measured  in agitated  slurries  should
nevertheless cause Option B to overpredict the  leachate
concentration.

     Finally, it should  be noted that  although  Option A is
supposed to correspond to the proposed regulation,  the  numeric
limits calculated by SLUDGEMAN differ  somewhat  from the numeric
limits presented in the  proposed regulation.  The numeric limits
of the proposed regulation were  computed with a large computer
using an earlier version of the  SLUDGEMAN program.  The numeric
limits of Option A were  computed on a  personal  computer using the
current version of SLUDGEMAN.  Among Class 1 numeric  limits,
Option A differs from the regulation for arsenic and  copper.
Among Class 2 numeric limits, Option A differs  from the
regulation for arsenic,  cadmium, lead,  and mercury  (i.e., all
metals for which an exact value  is computed).   The  precise origin
of this difference is not known.
 Alternative Approaches for Modeling Organic Leachate Generation

      The two alternatives considered here both  set the ratio of
 the  sludge concentration to the leachate concentration, c,/cd,  as
 a  function of Koc, the organic  carbon partition  coefficient.
 Thus, both options employ conventional partitioning theory.  For
 each pollutant the value assigned to Koc  is presented in Table  4.
 For  both alternatives only the ratio, not the absolute
 magnitudes, of cs and cd affect the numeric limit  computed  by
 SLUDGEMAN.

      Option A uses the c,/cd ratios presented  in the main body  of
 this  Technical Support Document, and used to generated the
 numeric limits in the proposed regulation.  For benzene,
 chlordane, dimethylnitrosamine, Lindane, TCE, and toxaphene, the
 ratio was set by Equation 3, assuming 50 percent organic carbon
 in the sludge solids, and 5 percent (not 20 percent) solids
 content in monofilled sludge.   For benzo(a)pyrene, BEHP, DDT,  and
 PCB, however,  the ratio was set, perhaps questionably,  by  other
 methods noted in Table 4.

     Option B determines the cs/cd ratios for  all pollutants from
 Equation 3.  The sludge solids are again assumed to be 50 percent
 organic carbon;  however,  the solids content of  the monofilled
 sludge is assumed to be 20 percent.   The assumption about percent
 solids (20% versus 5%) only affects numeric limits for pollutants
with low Koc,  that is, pollutants having  a significant fraction
dissolved in the sludge liquid.

     For the  two options,  Table 4 compares the  ratio c3/cd  and
the resulting numeric limit computed by SLUDGEMAN.  As this ratio
is  a key parameter,  changes in this ratio are reflected in


                               B-8

-------
proportional  or nearly proportional  changes  in the  computed
numeric limit.

      As with  the metals, it  must be  noted that Option A, while
intended to correspond to the  proposed regulation,  differs
slightly for  a  few pollutants:   benzo(a)pyrene,  BEHP,  and DDT.
Also,  for PCB the calculated numeric limits  are not used in  the
regulation, which instead uses the value from a previous
regulation.
Table 4:  Comparison  of two  options  for modeling
           organic pollutant  leachate generation.
        Benz
      Koc (L/kg)
BaP   BEHP
Chi
Opt A+B  74   5.5E+6    2E+9  1.7E+5

      RATIO cs/cd (L/kg) IN SLUDGE
Opt A    55  3.23E+5*   18.4t  85700
Opt B    41  2.75E+6    1E+9   85000

      CLASS 1 NUMERIC  LIMITS (mg/kg)
Opt A   0.28      97     290     180
Opt B   0.21     830   >lE+5     180

      CLASS 2 NUMERIC  LIMITS (mg/kg)
Opt A   0.85     300    1600   >lE+4
Opt B   0.63    2600   >lE+4   >lE+4
DDT
                     5E+6
                       93**
                   2.5E+6
DMN  Lind
PCB
TCE  TOJ
               0.04  1080  3.2E+5   198   960
               19.4
                4.0
                     0.95
                    26000
                      64
                    >lE+4
             0.0019
             0.00039
              0.07
              0.015
              564
              544
              2.3
              2.2
               75
               72
          1.6E+6*
          1.6E+5
             660
              65
            1700
             170
      119
      103
      491
      484
      0.6   2.5
      0.52  2.4
       11
      9.5
      7.6
      7.5
For Option A, unless  otherwise noted,  cs/cd = 0.5 Koc + 19 (approximately).
This assumes that the  solids are 50% organic carbon and that the monofilled
sludge  is 5% solids.   The exceptions are as follows:
   * BaP and PCB,  origin of c3/cd unknown,  perhaps erroneous;
  ** DDT, c3 set at a maximum reported sludge  concentration,  cd set at a
     reported maximum effluent concentration for dissolved plus particulate
     pollutant (neither from the 40-City Study); and
   t BEHP, cs/cd set arbitrarily.

For Option B, in all  cases, c,/cd =0.5 Koc + 4.   This assumes  that  the solids
are 50% organic matter and that the  monofilled sludge is 20% solids.
                                   B-9

-------
                     SUPPLEMENT TO APPENDIX A

                Calculating Partition Coefficients
           from Concentrations of Pollutants and Solids
               Measured in Sewage Treatment Plants

     This discussion presents  a  theoretical framework  for
calculating the partition coefficient from pollutant and solids
concentrations in POTW sludge  and effluent.  This framework was
was constructed starting from  model principles  set  forth by
HydroQual (1981), as described also by Delos et al.  (1984) and
HydroQual (1986).  The basic principles, originally applied to
natural waters, are applied here to the processes occurring in
the secondary clarifier of a municipal wastewater treatment
plant.

     In this approach the liquid and solid phases are  assumed to
equilibrate within the wastewater aeration tank (or equivalent
treatment process).  The secondary clarifier (illustrated in
Figure 2) then produces a sufficient degree of  solids  separation
to allow the partition coefficient to be calculated from the
measured quality in the upper  and lower portions of the
clarifier.  The mathematical derivation is somewhat complicated
because the solids separation  is incomplete:  the effluent
retains some solids, while the sludge retains much  water.
Consequently, it is not assumed  that the effluent contains only
dissolved pollutant.  Nor is it  assumed that the sludge contains
only particulate pollutant.

     The following nomenclature  is taken from the above
references:

cti> Ct2:   Total concentration  of pollutant in effluent and sludge
          respectively [|ag/L] .

cdl, cd2:   Concentration of dissolved pollutant  in effluent and
          sludge respectively  [|ag/L].

cPi> CP2:   Concentration of pollutant bound to particles in
          effluent and sludge  respectively, expressed per unit
          volume [ (ag/L] .

rls r2:    Concentration of pollutant bound to particles in
          effluent and sludge  respectively, expressed per unit
          weight [ng/kg].

mls m2:    Concentration of solids in effluent and sludge
          respectively [kg/L].

          Partition coefficient applicable the  effluent and
          sludge respectively  [L/kg].  This parameter is the same
          as Kd, the distribution coefficient,  the  term used  in
          the main body of this Technical Support Document.  By
          definition,  IT  = r/cd.


                                 B-10

-------
      Flow from
      aeration
        tank
                                                   Effluent with
                                                    measured n^
                                                      and ctl
    Sludge with measured   <-
         m2  and ct2
  Figure 2:  Schematic  of  Secondary Clarifier,
     To determine the relationship between the partition
 coefficient  and the solids and pollutant concentrations in
 effluent  and sludge,  one may begin by noting  that  cti = cpi + c
and cpi =  rimi =
dissolved is  given by:
cdl/ctl =
                         It  then follows that the fraction
                                     cd2/ct2 =
                                                l + TT2m2)
      The  following key assumptions are now made.   First,  it is
 assumed that
                = ir
                      in keeping with the  idea  that equilibration
 occurs  prior  to  entry to the secondary clarifier.   Hereafter the
 partition coefficient applicable to both the effluent  and the
 sludge  will simply be denoted IT.  (The effect of potential error
 in this assumption is discussed later. )  Second it  is  assumed
 that  the rate of decay of pollutant in the  sludge is zero,  which
 should  be appropriate for metals.  Under these conditions,
 r1 = r2  and cdl = cd2,  as discussed by Delos  et al.  (1984), among
 others.   Consequently,  interchanging cdl and cd2  in  the  above
 equations yields:

                                                 l + nm2)
                                                       l + irm2)
                                     cdl/ct2 =

Since cdi = cti  -  cpi,  where cpl =  rjrv,,  then:

(ct2-m2r2)/ctl  =  l/(l+-rrm1)              (c^-n^rj

Solving for r±:

r2  =  {ct2  -   c^/tl+irmj }  / m2        r,  = {ctl

Since r1 = r2, the equations  can be combined:
                                                  ct2/(
                          m
                              =   {ct
                                          ct2/( l + Trm2
This equation contains  the partition coefficient, TT ,  whose value
we wish to calculate, and the four measured parameters,  ctl and
ct2 (the total concentration of the pollutant  in  effluent and
sludge) and m^ and m2 (the solids concentrations  in  effluent and
                                B-ll

-------
 sludge).   As written, the value of  IT  could be determined
 numerically,  by trial-and-error iteration.

      Alternatively,  a simple analytical  solution for TT can be
 produced  as follows.  Algebraic rearrangement of the above
 equation  yields:

 ct2 (iT^^mj  + 2irm1m2 + im^2 + n^  + m2)

                            = ctl  (TT2m22ma + 2irm1m2  +  Trm22 + n^  +  m2)

 In application to the secondary clarifier of a sewage treatment
 plant,  it should be  noted that m1«m2.   That is,  the solids
 concentration in effluent is always much less than that in
 sludge,  as evidenced by the data of the  40 City  Study.
 Consequently,  the additive n^  term is always  an  insignificant
 portion of the sum,  and can thus be dropped from both sides of
 the equation.   Furthermore, on the  left  side of  the equation,
 irmj2 must always be insignificant compared to 2Tim1m2, and may
 therefore be dropped.  On the right side of the  equation,  2irm1m2
 is always insignificant compared to TTm22,  and therefore could be
 dropped.   However,  it is more convenient to drop only one-half
 the magnitude of 2irm1m2, thereby leaving  irm^ in its place.
 These approximations yield:

     ct2 (TT2m12m2 + 2irm1m2  + m2)  =  ctl  (TT2m22m1  +  Trm.[m2  + irm22 + m2)

 which,  by factoring  out m2,  reduces  to:

         ct2 (ir2!!^2  + 2'nm1  +  1)   =  ctl  (TT2m2m1 + TriT^  +  Trm2  +  1)

 This equation simplifies to:

                ct2 (Tim,  + I)2  =  ctl  (nm2  + l)(Trm1 +  1)

 or:

                 ct2 (Trm,  +  1)   =  ctl (Trm2 + 1)

 Algebraic  rearrangement yields a solution for TT :

              f  =  (c« -  ctl) /  (ctlm2  -  ct2ma)

      This  equation should be valid  provided that partitioning has
 approached equilibrium  within the sewage  treatment facility,
provided that  the partition coefficient  maintains  the same value
 in the effluent  and  the  sludge, and provided that  the
 concentration  of  solids  is much less  in  the effluent than in the
 sludge.

     The assumption  that tr maintains  the  same value in both
effluent and  sludge  is  important.    If the  partition coefficient
were to display an inverse relationship  with the concentration of
solids, then •n1 would exceed ir2, and this analysis would tend to


                               B-12

-------
overestimate the partition coefficient  applicable  to  sludge.  As
noted previously,  such an inverse  relationship  is  often  found in
measurements in media undergoing motion due  to  mechanical mixing.
However, the partition coefficient in a stationary sediment
medium having high solids concentration appears to maintain  the
value it would have in a low  solids medium  (DiToro et al. 1985,
HydroQual 1986).  As sludge is  a stationary  medium after
disposal, the partition coefficient applicable  to  a low  solids
environment should be appropriate.  In  that  case,  the value
calculated here should not be an overestimate.

     Data for four metals, arsenic, cadmium,  lead,  and mercury
were evaluated in this way.  Table 5 presents the  data and the
calculated results.

     The first column of the table identifies the  POTW by number.
In  the column following the POTW identification number,  an "s"
indicates that a single process was involved in separating the
solids from the liquid.  In nearly all  cases this  means  that the
data for the effluent and the sludge leaving the secondary
clarifier were used.  However,  for a few plants it means that
data for the sludge decant liquid  and the dewatered sludge were
used.  An "n" following the identification number  indicates  that
more that one process was involved in separating solids  from
 liquid, usually meaning that the sludge measurements  were for a
mixture of primary and secondary sludge.  The potential  for
confounding influences seem somewhat less where only  a single
process is involved in the solids  separation.

     The table then presents the solids concentrations (mg/L) and
pollutant concentration (fjg/L)  for both effluent and  sludge, as
presented by Burns and Roe (1982).  Where the pollutant  was
undetected in the effluent, the detection limit followed by  a.
minus sign,  indicating "less than", is  tabulated.   The pollutant
concentration in sludge, converted to mg/kg, was calculated  from
the quotient of pollutant and solids concentrations in sludge.

     The partition coefficient calculated for each metal is  then
tabulated.   Two things should be noted  here.  First,  where the
pollutant was undetected in the effluent and portrayed as being
less than the detected limit,  all  that  can be said about the
partition coefficient is that it is greater  than the  calculated
value.   A plus sign following the  tabulated  value  denotes
"greater than".   Second, where the  partition coefficient is  very
large,  above 10s  -  106 L/kg, nearly all  of the pollutant  in both
the sludge and the effluent is bound to particulate matter,
little of it is dissolved.   Consequently,  this  type of analysis
is unable to discern the exact value of very large  partition
coefficients.   Where the data indicate  a very large partition
coefficient,  a value of IxlO6  is reported  in Table  5.   Placing
this upper limit on the reported partition coefficient has no
effect  on the median and lower percentile values, however.

                             B-13

-------
     For cadmium,  a relationship between the degree of sludge
contamination and the partition coefficient was clearly apparent.
The less contaminated sludges tended to have lower partition
coefficients; the more contaminated sludges tended to have higher
partition coefficients.   For lead, arsenic, and mercury this
tendency was not as strong.   As the main regulatory interest is
in typically contaminated sludges or worse, the least
contaminated sludges were disregarded in statistically
summarizing the results.   For cadmium,  POTWs with less than 5
mg/kg were disregarded,  leaving 34 of 46 in the analysis.   For
lead, POTWs with less than 100 mg/kg were disregarded, leaving 44
out of 49 in the analysis.  For arsenic, those with less than 2
mg/kg were discarded, leaving 29 out 34 in the analysis.  For
mercury, those with less than 0.5 mg/kg were disregarded,  leaving
41 out of 45 in the analysis.  It might be noted that eliminating
the least contaminated sludges also has the effect of eliminating
the samples having the greatest relative measurement error.

     The results were previously summarized in Table 2,  which
presented the estimated median, 10th percentile,  and 5th
percentile.  For these estimates, "greater than"  and "less than"
values were disregarded whenever it was not possible to know
whether the true value was higher or lower than the median or
percentile value.
                              B-14

-------
Table 5:  Observed Concentrations  and  Calculated Partition
          Coefficients for Four Metals,  40-City Study.
1

Plant
1 s
2 n
3 n
4 n
5 n
6 n
7a n
7s s
8a n
8s s
9 s
10 s
11 s
12 s
13 s
14 s
15 n
16 n
17 s
18 s
19 s
21 s
22 n
23 s
24 s
27 s
28 s
29 s
30 s
31 s
32 s
33 s
34 s
35 s
36 B
37a s
37t s
38 s
39 s
40 3
51 s
52 n
53 s
54 s
57 n
58 n
59a n
59s s
60 n
— Solids --I
Eff
mg/L
20
9
12
43
12
27
18
2877
69
273
14
16
14
14
13
9
27
16
9
21
29
29
22
18
31
11
24
44
7
19
15
14
11
22
38
7
22
5
20
54
9
23
9
50
49
11
15
86
33
Sludge
mg/L
6300
21714
31859
59667
26433
51782
35057
26313
76755
189100
6281
555
1396
9017
28422
5200
126667
30330
3661
11334
16500
17531
37500
1215
340
6200
8750
2513
8977
5710
2007
17233
3068
22537
4110
3703
1348
2482
575
1190
28317
58400
4694
5360
32430
43124
29974
29974
43000
i
i
Eff
ug/L
4
2
1
1
1
65
5
139
2
2
2
1
8
15
2 -
2 -
2 -
2
4
2 -
2
2 -
2 -
14
2
2
7
2
2
2
5
2
2
1
6
2
16
2
1
2
4 -
2 -
2 -
4
96
3
100
100
2
	 fa
\*a
dmium
Sludge
ug/L
344
305
42
518
385
79833
498
313
450
780
152
24
29
9105
155
26
585
560
357
143
2727
131
150
365
7
74
597
10
26
48
15
13
5
516
6
1168
433
210
16
12
78
23
200
14
45483
458
84
84
241
mg/kg
55
14
1
9
15
1542
14
12
6
4
24
43
21
1010
5
5
5
18
98
13
165
7
4
300
21
12
68
4
3
8
7
1
2
23
1
315
321
85
28
10
3
0
43
3
1402
11
3
3
6


i
	 1
Part Coef

1
7
1
1
1
6
3
6
3
4
1
1
2
1
2
2
2
1
3
7
1
4
2
3
1
6
1
1
1
4
1
3
4
4
0
1
3
5
S
5
6
1
2
4
5
3


3
L/kg
.9E+04
.4E+03 +
.3E+03
.4E+04
.8E+04
.6E+04
.OE+03
.3E+01
.7E+03 +
.7E+03 +
.4E+04
.OE+05
.OE+03
.OE+05
.8E+03 +
.4E+03 +
.5E+03 +
.1E+04
.1E+04
.2E+03 +
.OE+05
.1E+03 +
.1E+03 +
.4E+04
.1E+04 +
.2E+03 +
.3E+04
.7E+03 +
.4E+03 +
.4E+03 +
.OE+03 +
.2E+02 +
.9E+02 +
.6E+04
.OE+00
.OE+05
.5E+04
.3E+04 +
.9E+04
.8E+03 +
.6E+02 +
.8E+02 +
.6E+04 +
.8E+02
. 1E+04
. 7E+03


. 1E+03 +
i
1
Eff
ug/L
20 -
3
30
53
4
18
47
1701
85
192
17
20
127
4
20
11
20
20
11
23
50
50
54
9
50
50
34
50
50
40
50
50
50
50
64
50
50
50
11
50
14
40
40
92
500
86
33
200
40


I fi^rl

Sludge
ug/L
1594
7386
1475
41000
8967
9667
44167
6133
98750
95250
2250
288
682
1917
10467
1817
14900
10600
1187
5200
3450
5033
77333
1060
155
1352
11400
1063
1557
3700
2214
3217
5017
7175
518
1800
1065
1087
100
55
7493
6308
840
430
194667
30134
2167
2167
18875
mg/kg
253
340
46
687
339
187
1260
233
1287
504
358
519
489
213
368
349
118
349
324
459
209
287
2062
872
456
218
1303
423
173
648
1103
187
1635
318
126
486
790
438
174
46
265
108
179
80
6003
699
72
72
439
I

Part Coef
L/kg
1.7E+04 +
1. OE+05
1 .5E+03
2.9E+04
1. OE+05
1 .4E+04
5.2E+04
1.6E+02
1. OE+05
9.2E+03
3.0E+04
4.1E+04 +
3.3E+03
1. OE+05
2.4E+04 +
4.4E+04
7. OE+03 +
2.4E+04
4.0E+04
3.4E+04
4.7E+03 t
6.8E+03 +
1. OE+05
1. OE+05
8.6E+03 +
4.4E+03 +
1. OE+05
1 . 3E+04 +
3.4E+03 +
2.3E+04 +
3.2E+04 +
3.9E+03 +
5.1E+04 +
7.4E+03 +
1.9E+03
l.OE+04 +
2.3E+04 +
8.7E+03 +
2.1E+04
8.8E+01 +
2.3E+04
2.9E+03 +
4.4E+03 +
7.2E+02
2.9E+04
8.9E+03
2.2E+03
3.4E+02 +
1.7E+04 +
                                B-15

-------
Table 5  (Continued)-   Data from 40-City  Study.
1 	 arsenic 	 1 | 	

Plant
1 s
2 n
3 n
4 n
5 n
6 n
7a n
7s s
8a n
8s s
9 s
10 s
11 s
12 s
13 s
14 s
15 n
16 n
17 s
18 s
19 s
21 s
22 n
23 s
24 3
27 s
28 s
29 s
30 s
31 s
32 s
33 s
34 s
35 s
36 a
37a s
37t s
38 s
39 s
40 s
51 s
52 n
53 s
54 3
57 n
58 n
59a n
59s s
60 n
Eff
ug/L
50 -
50 -
2
50 -
50 -
50 -
3 -
56
50 -
500 -
2


50 -
50
1
50
12
50
50 -
50 -
9
50
50 -

50 -
50 -
50 -
50 -
3
10 -
50 -
50 -
50 -
4
50 -
50 -
50
50
50
1
1
3
1
2
20
1
1
1
Sludge
ug/L
63
149
138
403
78
212
332
207
695
1463
19


19
192
38
1247
868
16
57
131
360
53
1

19
30
15
99
36
55
228
25
104
23
4
6
11
1
31
403
615
4
8
216
122
13
13
52
mg/kg
10
7
4
7
3
4
9
8
9
8
3


2
7
7
10
29
4
5
8
21
1
1

3
3
6
11
6
27
13
8
5
6
1
4
4
2
26
14
11
1
1
7
3
0
0
1
Part Coef

4.
9.
2.
1.
2.
6.
3.
1.
1.
1.
1.



1.
7.
1.
2.

1.
9.
2.
1.





1.
2.
2.
2.

4.
1 .





1.
1.
7.
1.
3.
1 .
4.
4.
I .
L/kg
1E+01 +
1E+01 +
2E+03
2E+02 +
1E+01 +
3E+01 +
3E+03 +
7E+02
7E+02 +
OE+01 +
4E+03



OE+02 +
6E+03
9E+02 +
4E+03

2E+01 +
9E+01 +
4E+03
6E+00 +





1E+02 +
OE+03
3E+03 +
1E+02 +

8E+01 +
2E+03





6E+04
4E+04
1E+01
4E+03 +
9E+03
2E+02
OE+02
2E+02 +
2E+03
Eff
ng/L

57
1000 -
450

200
1000
1000
200 -
225
1000 -
60
167
200 -
200
1000
200
183
200
200
100
233
200

200
50
133
650
200
1000
300

133
150
1000
133
267
200
217
567
1000
1000
167
1000
500
500
67
233
1000
	 nercury 	 1
Sludge
ng/L

3286
29250
360000

486667
205000
140500
172500
505000
46333
12000 -
8167
17167
33000
21500
142000
35167
24167
4833
79167
65333
60667

9000
49667
53167
7167
15333
6167
18000

500
6000
5333
2167
5000
1833
5000
5000 -
60000
158200
100333
33333
194667
51833
27500
27500
284750
ng/kg

151
918
6033

9398
5848
5340
2247
2671
7377
21622
5850
1904
1161
4135
1121
1159
6601
426
4798
3727
1618

26471
8011
6076
2852
1708
1080
8969

163
266
1298
585
3709
739
8696
4202
2119
2709
21375
6219
6003
1202
917
917
6622
Part Coef


2
9
3

1
6
1
5
1
8
1
6
1
6
4
6
7
4
2
1
3
9

1
1
1
4
9
9
5

9
1
1
4
1
3
1
1
2
2
1
8
2
2
1
5
8
L/kg

.7E+03
.OE+02
.2E+04

.OE+05
.5E+03
.OE+05
.OE+04
.OE+05
.OE+03
.OE+05
.7E+04
.1E+04
.2E+03
.1E+03
.6E+03
.OE+03
.7E+04
.1E+03
.OE+05
.OE+04
.BE+03

.OE+05
.OE+05
.OE+05
.9E+03
.OE+03
.2E+02
.3E+04

.1E+02
.8E+03
.1E+03
.3E+03
.9E+04
.4E+03
.OE+05
.1E+04
.1E+03
.9E+03
.OE+05
.8E+03
. 9E+04
.4E+03
.7E+04
.9E+03
.4E+03



+





+

+
-

+
+
+
+

+



+





+
+
+



+


+


+
+

+




+
                          B-16

-------
                            References

 Burns  and  Roe  Industrial  Services  Corp.   1982.   Fate  of Priority
 Pollutants in  Publicly  Owned  Treatment  Works.   EPA 440/1-82/303.
 Office of  Water  Regulation  and  Standards,  U.S.  Environmental
 Protection Agency, Washington,  DC.

 Delos,  C.G., W.L.  Richardson, J.V.  DePinto,  R.B.  Ambrose,  P.W.
 Rodgers, K. Rygwelski,  J.P. St.  John, W.J.  Shaughnessy,  T.A.
 Faha,  W.N.  Christie.  1984.   Technical  Guidance Manual  for
 Performing Waste Load Allocations,  Book II  Streams and  Rivers,
 Chapter 3  Toxic  Substances.   EPA-440/4-84-022.   Office  of  Water
 Regulations and  Standards,  U.S.  Environmental  Protection Agency,
 Washington, DC.

 DiToro,  D.M.   1985.  A  Particle Interaction Model of  Reversible
 Organic Chemical Sorption.  Chemosphere 14:1503-1538.

 DiToro,  D.M.,  J.S. Jeris, and D. Ciarcia.   1985.   Diffusion and
 Partitioning of  Hexachlorobiphenyl  in Sediments.   Environ. Sci.
 Technol. 19:1169-1176.

 DiToro,  D.M.,  J.D. Mahony,  P.R.  Kirchgraber, A.L.  O'Bryne, L.R.
 Pasguale,  and  D.C. Piccirilli.   1986.   Effects  of
 Nonreversibility,  Particle  Concentration,  and  Ionic Strength  on
 Heavy  Metal Sorption.   Environ.  Sci. Technol.  20:55-61.

 Gerritse,  R.G.,  R. Vriesema,  J.W. Dalenberg, and H.P. DeRoos.
 1982.   Effect  of Sewage Sludge  on Trace Element Mobility in
 Soils.   J.  Environ. Qual. 11:359-364.

 Gschwend,  P.M.,  and S.  Wu.  1985.   On the  Constancy of  Sediment-
 Water  Partition  Coefficients  of Hydrophobic  Organic Pollutants.
 Environ. Sci.  Technol.  19:90-96.

 Honeyman,  B.D.,  and P.H.  Santschi.   1988.   Metals in  Aquatic
 Systems.   Environ. Sci. Technol. 22:862.

 HydroQual,  Inc.   1981.  Analysis of Fate of  Chemicals in
 Receiving  Waters,  Phase I.  Prepared for the Chemical
 Manufacturers  Association,  Washington,  DC.

 HydroQual,  Inc.   1986.  Technical Guidance  Manual for Performing
 Waste  Load  Allocations; Book  IV Lakes,  Reservoirs and
 Impoundments;   Chapter 3 Toxic Substances Impact.   EPA-440/4-87-
 002.   Office of  Water Regulations and Standards,  U.S.
 Environmental  Protection Agency, Washington, DC.

 Mackay, D., and  B. Powers.  1987.   Sorption  of  Hydrophobic
 Chemicals from Water:    a Hypothesis  for  the  Mechanism of the
 Particle Concentration  Effect.  Chemosphere  16:745-757.

Metcalf and Eddy,  Inc.  1972.   Wastewater Engineering.   McGraw-
Hill, New York.
                               B-17

-------
SCS Engineers [undated].   Selection and Monitoring of Sewage
Sludge Burial Case Study Sites.   As referenced by U.S. EPA 1978.
Process Design Manual Municipal Sludge Landfills.  EPA-625/1-78-
010, SW-705.

U.S. Environmental Protection Agency.   1985.  Environmental
Profiles and Hazard Indices for Constituents of Municipal Sludge.
Office of Water Regulations and Standards, Washington, DC.

U.S. Environmental Protection Agency.   1986.  Development of Risk
Assessment Methodology for Municipal Sludge Landfilling.
Environmental Criteria and Assessment Office,  Cincinnati, OH.
                              B-18

-------
                APPENDIX B
Sensitivity Analyses on Selected Model Parameters

-------
       Results of Sensitivity
     Analyses for Sewage Sludge
             Landfill ing
            December  1987
             Prepared  by

            G. W. Dawson
            C.  A.  Newbill

        ICF Technology, Inc.
        Richland, Washington
                 for
 Wastewater  Solids  Criteria  Branch
U.S. Environmental Protection Agency

-------
                         Results of Sensitivity
                       Analyses for Sewage Sludge
                               Landfill ing

     EPA  is  required,  under Section 405(d) of the  Clean Water Act, to
develop regulations  for  the use and disposal  of sewage sludge.  One of
the  disposal   options  is  landfill ing.     The  regulation  regarding
landfill ing  uses  the SLUDGEMAN model to  predict  the maximum allowable
concentrations   of  pollutants   in  sewage   sludge  that   will   not
detrimentally affect an MEI  (Most  Exposed  Individual) who drinks ground
water from the site  100% of  the time over  a 70 year  lifespan.
     This  document  summarizes  the  results   of  sensitivity  analyses
conducted   on   the   model  showing   how  maximum   allowable   sludge
concentrations vary with sludge and site-specific factors.  Initially a
base  case scenario  was  run  against  which all  subsequent  runs  were
compared.   The  input parameters  for the  baseline  case are  shown in
Tables 1 through 4.  For each  sensitivity  run, selected parameters were
varied  and  these  are  shown  in  Table  5.   Table  6 shows  the  health
effects  levels  against  which  final  concentrations were  compared in
order to  calculate allowable dry weight sludge concentrations for each
chemical.
     The  seven  parameters  varied were:  1) distance  to the  point of
compliance,  2)  depth  to  ground  water,  3) net  recharge,   4)  aquifer
thickness,  5)  groundwater  velocity,  6) groundwater  chemistry,  and 7)
sludge moisture content.   One  would expect  that increasing the distance
to  a downgradient  point  of interest would  result   in  lower chemical
concentrations  there,  thus  allowing  higher chemical concentrations in
the  sludge.   The changes  result  in  more  time  and space for dispersion
of the chemicals in  the aquifer over the greater distance.  Conversely,
decreasing  the  distance   to  a  point  downgradient  from the landfill
decreases  chemical  dispersion  and increases  chemical  concentrations.
Thus lower initial  concentrations are allowed  in  the landfill if final
concentrations  at  the downgradient point  are  to be kept under health
effects levels.
     For  a similar  reason,  one  would  expect  increasing the  depth to
groundwater  and  thickness of  the  aquifer  would  allow more dispersion,
thus  reducing  the  final   chemical  concentrations  and  allowing  higher
concentrations  in   the  sludge.    Conversely,  decreasing the  depth to
groundwater  or  aquifer  thickness  have the  opposite effect;  that of
decreasing dispersion  and  thus producing  higher outflow concentrations
and allowing lower initial  concentrations  in the sludge.
     Increasing the  depth  to groundwater  or distance to the compliance
point can also decrease outflow concentrations by allowing greater time
for  chemicals  to   degrade.     For  most  of the  chemicals  simulated,
degradation  is  not  a  significant  factor,  but it  is for  some  of the
organics,  namely Chlordane,  DDT,  DMN, Lindane, and  TCE.   On the other
hand, decreasing the distance  to  a downgradient point or decreasing the
depth to groundwater reduces the  chemical  travel time  and  thus allows
less  degradation   to  take  place.    This  results   in  higher  outflow
concentrations  and  lower  allowable  sludge concentrations  if  outflow
concentrations are  to be kept under health effects levels.

-------
     Sludgeman  uses  net  recharge  to   determine  the  rate  at  which
leachate leaves the  landfill  and  travels through  the unsaturated zone.
Therefore,  increasing recharge has the effect of increasing leach rates
from the landfill  and decreasing  unsaturated zone travel  times.   This
should  increase  chemical  concentrations  at a  downgradient point  of
interest,  other factors  being  constant.   Conversely,  lower  recharge
causes  slower  leach  rates  and  higher  travel  time  in  the unsaturated
zone.   This  creates  slower  leach rates into the  saturated  zone,  thus
allowing greater dilution  from  the  generally higher  flow  rates  in  that
zone.   Also,  the  longer  travel  time  in  the unsaturated zone  allows
greater degradation there for chemicals which are degradable.
     Increasing groundwater  velocity creates a  greater  volume  of water
into which each year's  recharge  is  mixed.   Hence,  higher  velocities
lead to more dilution and greater allowable  sludge concentrations while
slower  velocities  have  the opposite effect.   For degradable  chemicals,
there  is  a  countervailing  effect because the  slower velocities  allow
more  travel  time  for degradation.   Groundwater  geochemistry  affects
inorganic  constituent  solubilities  and  thereby  controls  groundwater
concentrations  for  some  contaminants.  In general, reducing  conditions
and  lower  acidities  reduce  solubilities.    Finally,   sludge  moisture
content changes the  overall  solids  content  of a given volume of sludge
and,  therefore,  its  inventory of  contaminants.   As  sludge  moisture
increases,   allowable  sludge concentrations  increase  and  conversely,
allowable  levels go down with moisture content.
     The results  of  the  Sludgeman sensitivity  runs were  in agreement
with these concepts.    There were  cases,  however, in which  changing a
hydrologic parameter  did not seem to  produce the expected result.  This
occurred, for example, when  the depth to groundwater was increased from
the  base  line  case  of 0  meters  to  10  meters.    For some chemicals--
benzene for  example  --  no  decrease in outflow concentration  was  found.
This was due to the  extremely  long  release  time  from the landfill  for
this chemical.  The  release  time  from the landfill was  so much greater
than the travel time  across  the unsaturated  zone,  that  the unsaturated
zone  didn't   have   enough  time  or  distance  to   reduce   the  peak
concentration below that leaching directly from the landfill.  The time
of peak outflow concentration at the  downgradient point  of interest was
significantly increased, but the  peak concentration  was the  same.   The
principles  of hydrology were still  in effect,  but  the unsaturated  zone
was  just not large  enough to  disperse  the  very  long  pulse  below  its
peak concentration.
     Another example  is the  concentration  of  BEHP.   BEHP  has  a  very
high Kd in  the unsaturated zone, so one would expect the presence of an
unsaturated  zone   to  greatly   influence  the   outflow  concentration
downgradient from  the landfill.   This  is  because the  pulse  from  the
landfill spends  so much  time   in  the unsaturated  zone,  that  there  is
ample opportunity to disperse the peak below the leachate concentration
from the landfill.  When we  simulate a 1 meter  thick unsaturated zone,
we indeed find this to be the case.  Outflow concentrations are reduced
by a  factor  of over  100.   But when we increase  the unsaturated  zone
thickness to  5 meters and then 10 meters, we find very little change in
the BEHP concentration at  150 meters downgradient.   The reason  is that
although we  are continuing  to  significantly decrease  the groundwater

-------
concentration at 150 meters, the groundwater concentration is no longer
the  dominant  influence  in  the total  final  concentration.   The vapor
concentration is now the controlling factor.  Therefore, decreasing the
groundwater concentration  has  little  effect  on the  total  exposure at
the point of interest.
     In  addition  to  demonstrating  the  direction   and   magnitude  of
effects  arising  from  changes in   input  parameter  values,  the  data
provided here can be used to select  allowable sludge concentrations for
contaminants for settings that  differ from the base cases.  In order to
do  this,  the  applicant  should refer  to Table 5  and find the  set of
conditions which  matches the  characteristics of the  site of interest.
The right hand column then indicates which table of values will  provide
the  controlling  sludge  conditions  for that site.   For example,  if the
site of  interest  is situated  so that  the  exposure point  is 150 meters
from the  site  boundary, has  an annual  recharge level  of 0.5 m/yr, an
aquifer thickness  of 76.8  meters,  a groundwater velocity of  100 m/yr,
soil  organic  content  of  0.0001,   and   a  depth to  groundwater of 10
meters;  the  site  is  equivalent  to  case S7-150T1,  Table  30.    The
allowable sludge  concentrations for that case  are  shown  in  the table.
When conditions  are  not precisely  the  same  as a case  run  here,  the
closest more  conservative case should  be  selected.    In  general,  the
conservative  case  is  identified   by  rounding down   on  distance  to
exposure  point,  depth  to  groundwater,  soil  organic  content,  aquifer
thickness,  and  groundwater  velocity.    Recharge should be rounded  up.
If there are doubts as to the  case that  is most appropriate, review all
similar cases and use the most  restrictive allowable sludge criteria.
     The  sensitivity  analyses were  compared for the  10"** level  health
effects.   The  10"^  and  10"° health effects levels  were  also compared
against, but it was  found  that the allowable  dry weight concentrations
for  those  levels  differed from the 10"^  level  by simple multiples of
10.  For  example,  the  10~5  health  effects level allowed  1/10 the level
of  sludge concentration  as  the 10"^ level, and the 10"°  level  allowed
1/100 the level  of sludge concentration.  Therefore, once the allowable
dry  weight concentrations   for the 10"^  health  effects level  were
calculated, those  for the  10"^ and  10"°  levels  could be immediately
calculated by dividing by 10 and 100, respectively.
     The  reason  is  that for  the  organics, leachate  concentration is
linearly related to dry weight  concentration in the sludge.  Therefore,
when   the  dry   weight   concentration   is   changed,   the   leachate
concentration is  changed proportionally.  This  means  the release time
remains constant,  and  as  well  as  the  peak  travel  time,  causing  the
effects of dispersion  and  degradation remain the  same.   The resulting
concentration  at  a monitoring  point is then directly proportional to
the change in  leachate and dry  weight concentrations.
     The  input  parameters  and  varied parameters were  supplied  by EPA.
Many came from the EPA Hazard  Profiles for 1985.
     The designations  for  the  sensitivity runs  are  descriptive  of the
parameters varied.   The designations  are  shown in Table 5  along with
the parameters varied.   The  designations are  also  listed  at the top of
each  sensitivity   run  result   table  as  a quick   indication  of  what
parameters were varied  for that run and what  values  were  used.   Most
designations begin with  an  "S" indicating a sensitivity  run,  the base

-------
case simulations for each  distance  beginning  with  a "B".   The number 4
immediately following the  "B" for the base case runs indicates the case
was  run  for  the  10"^  health  effects  level.   The  number immediately
following the  "S"  for the sensitivity  runs  indicates  basic parameters
changed for that sensitivity run.  These codes can briefly be described
as:

 B4  - Base Case at 10-4 health effects level
 S7    10 meters to groundwater, FOC =  10-4
 S8    10   "    "      "      , FOC =  10-2
 S9  -  5 meters to groundwater, FOC =  10-4
 S10 -  5   "           "      , FOC =  10-2
 Sll    5 meters to groundwater, FOC =  10-4
 S12 -  1               "      , FOC =  10-2
 S13   0.25 m/y recharge instead of 0.5
 S14 - 0.00635 m/y recharge
 S15 - 1000 m/y groundwater velocity instead of 100
 S16 -   10 m/y
 S17 -    1 m/y      "          "       	
 S18 - 560   m aquifer thickness instead of 15 m
 S19 -  78.6 m    "        "        	
 S20 -   5.0 m    "        "        "    "  "  "
 S21 - eh =  150 instead of 500
 S22   eh = -200    "    "   " , ph = 7.0 instead of 6.0
 S23   sludge moisture capacity = 0.95  instead of 0.80
 S24 - sludge     "        "    " 0.60	

     The  S7   through   S12  cases   have  additional  sensitivity  runs
associated  with  them.     Combinations   of   net  recharge   and  aquifer
thickness were also varied, in addition to the basic variances in depth
to  groundwater  and  FOC.     These   changes  were   indicated  with  the
additional designations of Rl, R2,  Tl,  and T2 indicating

 Rl - net recharge = 0.25 m/y instead of 0.5 m/y
 R2 - net recharge = 0.00635 m/y
 Tl - aquifer thickness = 78.6 m instead of 15 m
 T2 - aquifer thickness =  5.0 m.

Thus  S7-150R1T2   indicates  the  depth  to  groundwater  was  10  meters,
distance to  a  monitoring  well  150  meters,  net recharge  0.25 m/y,  and
aquifer thickness 5 meters.
     In Table  5,  all  sensitivity parameter  values are listed  for  the
first  simulation.   For  subsequent  sensitivity  analyses,  only  values
changed for  each  run  are  listed,  values remaining  unchanged  are left
blank.    Thus  it is easy  to see which  parameters  are  changing  by  the
values being  listed.    All  parameter values  are  listed  for  the first
simulation on a continued page.

-------
                               Table  1.
                     Baseline  Input  Concentrations,
Parameter
Leachate
Concentration
(mg/1 ) As
Cd
Cu
Pb
Hg
Ni
Benzene
B(A)P
BEHP
Chlordane
DDT/DDE/DDD
DMN
Lindane
PCB
Trichloroethylene
Toxaphene
Value (mq/1)


1 (a)
0.2 (b)
37 (b)
10 (b)
0.69 (f)
3.4 (c)
0.12 (d)
0.000006 (d)
25 (a)
0.00014 (d)
0.01 (e)
0.014 (d)
0.00039 (d)
0.0000018 (d)
0.022u(d)
0.15 (d)
Parameter
Dry Sludge
Concentration
(mg/kg) As
Cd
Cu
Pb
Hg
Ni
Benzene
B(A)P
BEHP
Chlordane
DDT/DDE/DDD
DMN
Lindane
PCB
Trichloroethylene
Toxaphene
Value (mq/Kq)


20.75 (a)
88.13 (b)
5600. (b)
1070. (a)
5.85 (a)
920. (a)
6.6 (a)
1.935 (a)
459. (a)
12. (d)
0.930 (d)
0.272 (e)
0.220 (d)
2.90 (d)
17.85 (d)
10.8 (d)
(a) Estimate based on estimated
liquid concentration to require
at least one year to deplete mass
in sludge.

(b) Indicates value was the max-
imum reported for leachate from
a sludge monofill. (EPA, 1978)

(c) Maximum effluent reported for
municipal  wastewaters.  (Barth et.
al., 1965)

(d) Indicates value was derived
from the sludge concentration and
the Koc at 5% solids and 50%
organic solids.
(e) Indicates
imum effluent
(EPA,  1978)
value was the max-
value reported
(f)  Value recommended by Betsy
Southerland,  June, 1987.
                      (a) Indicates value for 95th
                      percentile sludges surveyed.
                      (EPA, 1985a)
                      (b) Indicates
                      maximum value
                      surveys.
              value was
              between a
an average
number of
                      (c) Value selected to support
                      reported leachate level.
                      (d) Indicates value was the maximum
                      value reported.
(e) Indicates value was the mean
value reported.

-------
                    Table 2.

    Baseline Values for the Unsaturated Zone.
Sludge Moisture Content 0.80
Sludge Storage Capacity 0.90
Sludge Density 1025
Net Recharge 0.5
Landfill Width 100
Landfill Length 100
Depth to Ground Water 0
Inorqanic Kd's (1/kq)
As 5.86
Cd 14.9
Cu 41.9
Pb 234.
Hg 322.
Ni 12.2




kg/kg
kg/ kg
kg/nv3 (EPA Hazard Profiles)
m/yr
m (Proposed Land Ban Rule and
m Supporting Documents (1986))
m
Organic K0c's
Benzene
B(A)P
BEHP
Chlordane
DDT/DDE/DDD
DMN
Lindane
PCB
TCE
Toxaphene
(Kd = Koc * Foc)
74.
5,500,000.
2,000,000,000.
170,000.
5,000,000.
0.04
1,080.
320,000.
198.
960.
    Decay Rates (/yr)

         As      0
         Cd      0
         Cu      0
         Pb      0
         Hg      0
         Ni      0
    Benzene      0
      B(A)P      0
       BEHP      0
  Chlordane      0
DDT/DDE/DDD      0
        DMN      0
    Lindane      1.0
        PCB      0
        TCE      0
  Toxaphene      0

-------
                               Table  3.
                Baseline Values for the Saturated Zone
Material  Type
Effective Porosity
Ground Water Gradient
Hydraulic Conductivity
Ground Water Velocity
Effective Bulk Density
Eh
Ph
Aquifer Thickness
Aquifer Width
(perpendicular to flow)
Sand
0.1
0.005 m/m
2000  m/yr
 100  m/yr
2390  kg/m3
+500  mv
 6.0
  15  m

1000  m
                     Kd's (I/kg)
As
Cd
Cu
Pb
Hg
Ni




5
14
41
234
322
12




.86
.9
.9
.

'.2




Benzene
B(A)P
BEHP
Chlordane
DDT/DDE/DDD
DMN
Lindane
PCB
TCE
Toxaphene
0
0
0
0
0
0
0
0
0
0
               Decay Rates (/yr)
As
Cd
Cu
Pb
Hg
Ni
Benzene
B(A)P
BEHP
Chlordane
DDT/DDE/DDD
DMN
Lindane
PCB
TCE
Toxaphene
0
0
0
0
0
0
0
0
0
8.43
0.904
607.1
1.0
0
0.904
0

-------
                      Table  4.

Background Concentrations for Baseline Case (mg/1)

    As     0.0004              Benzene     0.
    Cd     0.001                 B(A)P     0.
    Cu     0.01                   BEHP     0.
    Pb     0.001             Chlordane     0.
    Hg     0.0003          DDT/DDE/DDD     0.
    Ni     0.0027                  DMN     0.
                               Lindane     0.
                                   PCB     0.
                                   TCE     0.
                             Toxaphene     0.

-------
               Table  5.
Parameters Varied for Sensitivity Runs.
Distance
to Comp- Depth
liance to GW
Point (m) (m) FOC
0. 0.
10. 0.
0.
5. 0.
0.
1. 0.
0.
10. 0.
0.
5. 0.
0.
1. 0.
0.
10. 0.
0.
5. 0.
0.
1. 0.
0.
150. 0. 0.
10.








0.








—
0001
01
0001
01
0001
01
0001
01
0001
01
0001
01
0001
01
0001
01
0001
01
0001









01








Aquifer
Recharge Thickness
(m/yr) (m)
0






0





0.





0

0
0
0

0

0

0
0
0
0

0

0

.5






.25





00635





.5

.25
.00635
.5

.25

.00635

.5
.25
.00635
.5

.25

.00635

	


















15.



78.6
5.
78.6
5.
78.6
5.
15.


78.6
5.
78.6
5.
78.6
5.
Designation Table
B4-0
S7-0
S8-0
S9-0
S10-0
Sll-0
S12-0
S7-OR1
S8-OR1
S9-OR1
S10-OR1
S11-OR1
S12-OR1
S7-OR2
S8-OR2
S9-OR2
S10-OR2
S11-OR2
S12-OR2
B4-150
S7-150
S7-150R1
S7-150R2
S7-150T1
S7-150T2
S7-150R1T1
S7-150R1T2
S7-150R2T1
S7-150R2T2
S8-150
S8-150R1
S8-150R2
S8-150T1
S8-150T2
S8-150R1T1
S8-150R1T2
S8-150R2T1
S8-150R2T2
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44

-------
          Table 5, continued.
Parameters Varied for Sensitivity Runs.
Distance
to Comp- Depth Aquifer
"Nance to GW Recharge Thickness
Point (m) (m) FOC (m/yr) (m)
150. 5. 0.0001 0.5
0.25
0.00635
0.5

0.25

0.00635

0.01 0.5
0.25
0.00635
0.5

* 0.25

0.00635

1. 0.0001 0.5
0.25
0.00635
0.5

0.25

0.00635

0.01 0.5
0.25
0.00635
0.5

0.25

0.00635

15.


78.6
5.
78.6
5.
78.6
5.
15.0


78.6
5.
78.6
5.
78.6
5.
15.0


78.6
5.
78.6
5.
78.6
5.
15.0


78.6
5.
78.6
5.
78.6
5.
Designation Table
S9-150
S9-150R1
S9-150R2
S9-150T1
S9-150T2
S9-150R1T1
S9-150R1T2
S9-150R2T1
S9-150R2T2
S10-150
S10-150R1
S10-150R2
S10-150T1
S10-150T2
S10-150R1T1
S10-150R1T2
S10-150R2T1
S10-150R2T2
Sll-150
S11-150R1
S11-150R2
S11-150T1
S11-150T2
S11-150R1T1
S11-150R1T2
S11-150R2T1
S11-150R2T2
S12-150
S12-150R1
S12-150R2
S12-150T1
S12-150T2
S12-150R1T1
S12-150R1T2
S12-150R2T1
S12-150R2T2
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
                   10

-------
          Table 5, continued.A:
Parameters Varied for Sensitivity Runs.
Distance
to Comp-
liance
Point (m)
50.






150.






500.






1000.






50.

150.

500.

1000.

Depth
to GW
(m)
0.
10.

5.

1.

0.
10.

5.

1.

0.
10.

5.

1.

0.
10.

5.

1.

0.







FOC
0.0001

0.01
0.0001
0.01
0.0001
0.01
0.0001

0.01
0.0001
0.01
0.0001
0.01
0.0001

0.01
0.0001
0.01
0.0001
0.01
0.0001

0.01
0.0001
0.01
0.0001
0.01
0.0001







Aquifer
Recharge Thickness
(m/yr) (m)
0.5 15.0



























0.25
0.00635
0.25
0.00635
0.25
0.00635
0.25
0.00635
Designation
B4-50
S7-50
S8-50
S9-50
S10-50
Sll-50
S12-50
B4-150
S7-150
S8-150
S9-150
S10-150
Sll-150
S12-150
B4-500
S7-500
S8-500
S9-500
S10-500
Sll-500
S12-500
B4-1000
S7-1000
S8-1000
S9-1000
S10-1QOO
Sll-1000
S12-1000
S13-50
S14-50
S13-150
S14-150
S13-500
S14-500
S13-1000
S14-1000
Table
81
82
83
84
85
86
87
26
27
36
45
54
63
72
88
89
90
91
92
93
94
95
96
97
98
99
100
101
1 102
103
104
105
106
107
108
109
                   11

-------
                          Table 5, continued.

                Parameters Varied for Sensitivity Runs.

      For these  sensitivity  runs, the  depth to the groundwater  was  0
meters,    FOC was  0.0001,  and recharge  was  0.5 m/yr.    The parameters
altered  were  groundwater  velocity,  aquifer  thickness,  groundwater
eh/ph, and sludge moisture content.
Distance
to Well
(m)
50.


150.


500.


1000.


50.


150.


500.


1000.


50.

150.

500.

1000.

50.

150.

500.

1000.

Aquifer
Thickness
(m)
15.











560.
78.6
5.0
560.
78.6
5.0
560.
78.6
5.0
560.
78.6
5.0
15.0















Velocity
(m/yr)
1000.
10.
1.
1000.
10.
1.
1000.
10.
1.
1000.
10.
1.
100.



























eh/ph
mv/su
+500/6.0























+150/6.0
-200/7.0
+150/6.0
-200/7.0
+150/6.0
-200/7.0
+150/6.0
-200/7.0








Moisture
Content Designation
0.80 S15-50
S16-50
S17-50
S15-150
S16-150
S17-150
S15-500
S16-500
S17-500
S15-1000
S16-1000
S17-1000
S18-50
S19-50
S20-50
S18-150
S19-150
S20-150
S18-500
S19-500
S20-500
S18-1000
S19-1000
S20-1000
S21-50
S22-50
S21-150
S22-150
S21-500
S22-500
S21-1000
S22-1000
0.95 S23-50
0.60 S24-50
0.95 S23-150
0.60 S24-150
0.95 S23-500
0.60 S24-500
0.95 S23-1000
0.60 S24-1000
Table
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
                                   12

-------
                               Table 6.

                     Health  Effects  Levels  (mg/1).

          Chemical          10'6         1CT5        10'4
0.05
0.010
1.3
0.05
0.002
1.75
0.005
0.000003
0.00248
0.000021
0.000102
0.000001
0.004
0.00000454
0.005
0.005
0.05
0.010
1.3
0.05
0.002
1.75
0.005
0.00003
0.0248
0.00021
0.00102
0.00001
0.004
0.0000454
0.005
0.005
0.05
0.010
1.3
0.05
0.002
1.75
0.005
0.0003
0.248
0.0021
0.0102
0.0001
0.004
0.000454
0.005
0.005
         As
         Cd
         Cu
         Pb
         Hg
         Ni
         Benzene
         B(A)P
         BEHP
         Chlordane
         DDT/DDE/DDD
         DMN
         Lindane
         PCB
         TCE
         Toxaphene

     Note:  The  health  effects  levels  vary for only 6  of  the  organics:
Benzo(a)pyrene,   Bis(2-ethylhexyl)pthalate,   Chlordane,   DDT/DDE/DDD,
Dimethylnitrosamine,  and  PCB's.   All  other chemicals  have  a  single
health effects level.
                                  13

-------
                               Table  7.

               Base Case,  Depth to Groundwater 0 Meters,
                      Distance to Wells 0 Meters.
84 0 -- Base Case.
 CHEMICAL
SAT CONC  VAPOR C   BCKGRND
SUM
HEL
CS
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
3.83E-12
6.82E-04
2.47E-06
1.10E-05
2.70E-06
O.OOE+00
4.50E-05
O.OOE+00
O.OOE+00
4.00E-04
l.OOE-03
l.OOE-02
l.OOE-03
3.00E-04
2.70E-03
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
O.OOE+00
5.04E-02
l.OOE-02
1.13E+00
5.24E-02
1.95E-03
1.75E+00
5.00E-03
3.00E-04
2.45E-01
2.09E-03
1.02E-02
l.OOE-04
4.00E-03
4.54E-04
5.00E-03
5.00E-03
5.00E-02
l.OOE-02
1.30E+00
5.00E-02
2.00E-03
1.75E+00
5.00E-03
3.00E-04
2.45E-01
2.10E-03
1.02E-02
l.OOE-04
4.00E-03
4.54E-04
5.00E-03
5.00E-03
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
                                   14

-------
                                Table  8.

             The  Effects  of Increasing Depth  of Unsaturated
                        Zone from 0 to 10 feet.

 S7-0, D to GW=10M, DIST=OM, FOC=10-4, R=0.5M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
5.64E+00
1.14E+00
1.51E+03
1.71E+02
4.73E+00
1.99E+02
2.75E-01
9.67E+01
1.62E+03
1.80E+02
4.08E+01
1.89E-03
6.16E+01
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
2720.0 %
3066.7 %
17876.2 %
49322.0 %
67471.4 %
2759.2 %
0.0 %
-0.1 %
35980.2 %
0.0 %
4212.9 %
0.0 %
2625.7 %
4.6 %
0.0 %
0.0 %
     As:  Travel  time  in  the  unsaturated  zone  allows  dispersion,
reducing  concentration  at  saturated  zone,  allowing  higher  sludge
concentrations.
     Cd: Same as for As.
     Cu: Higher Kd than for As or Cd  (41.9 vs 5.86 and 14.9) retains Cu
in unsaturated zone for longer period of time, allowing greater disper-
sion, lower concentrations, and higher allowable sludge concentrations.
     Pb: Same  as  for Cu.   Travel  time  of  1870  years  compared to pulse
time of 21  years  allows  significant dispersion of  contaminant plume,
allowing much  higher  sludge  concentrations  than  base case,  and  also
higher concentrations relative to base case than As or Cd.
     Hg: Same  as  Cu  and Pb.  High  Kd of 322 produces unsaturated  zone
travel  time of 2570 years  on  a  pulse of 8.4 years.  Significant unsat-
urated zone dispersion of a narrow plume results.
     Ni: Same  as  for As and Cd.   Kd of Ni  is  12.2 compared  with  5.86
and  14.9  for As  and  Cd.   Travel  time  of 144  years  on  a  pulse of 72
years yields significant dispersion, but not as much as for Cu, Pb, and
Hg.
     Benzene: Pulse time is 68 years but travel  time  is  only 14 years,
so dispersion  in  the  unsaturated zone has  insufficient  time  to reduce
peak.
     B(A)P:  Same  as  Benzene,  release time  is 397,000 years  while the
unsaturated  zone travel  time is  only 31,500 years.
                                   15

-------
     BEHP:  Very long travel  time,  1,800,000  years,  short release time,
22.6  years,   yields  high   dispersion   and  high   allowable   sludge
concentrations.  Vapor pathway controls  for  BEHP,  but not until  sludge
concentration reaches about 100 mg/kg.
     Chlordane: Release  time 100,000  years,  travel   time  2,700  years.
Contaminant  keeps   leaching  and  eventually   overcomes   effects   of
dispersion   in   unsaturated  zone.    Peak  takes   longer   to  reach  the
saturated  zone,  but  is  the  same  as   for  the  base  case  with  no
unsaturated zone.
     DDT: Vapor contributing but not controlling  (0.00047 mg/1  vapor vs
0.0097 mg/1  aquifer).    Travel  time  for  peak through the  unsaturated
zone is 4,600 years, release time 114 years.   Time spent  in unsaturated
zone is  sufficient  to  reduce peak concentration  allowing higher  sludge
concentrations.
     DMN:  Release  time  is  24 years,  peak  travel  time  is  14.6  years.
The peak traverses  the unsaturated zone  before  the  source  is  depleted
so the peak is not reduced.
     Lindane:  Travel time  of 7.4 years  allows  significant degradation
in the unsaturated zone.
     PCB: The  release  time of 2,000,000  years is significantly  greater
than the travel  time  of 50,000  years, so the 4.6%  increase indicated
over the base  case  is  probably not  significant.   Allowable sludge  dry
weight concentrations  are  probably equivalent in  both cases.
     TCE: Release time is  1000 years, travel  time only 25 years,  so the
peak traverses  the  unsaturated  zone before the  source is depleted,  so
the peak is not reduced.
     Toxaphene: Same as  for  TCE,  release  time is 89  years, travel time
only 19  years, dispersion   affects  peak  travel   time  to  saturated zone
but not peak concentration.
                                   16

-------
                                Table 9.

             The Effects of Increased Depth to Groundwater
               and a Higher Organic  Content in the Soil.

 S8-0, D to GW=10M, DIST=OM, FOC=10-2, R=0.5M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
5.65E+00
1.14E+00
1.54E+03
4.73E+00
2.00E+02
2.75E-01
1.58E+02
1.63E+03
1.80E+02
7.31E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
5.10E-01
% DIFFERENCE
2725.0 %
3066.7 %
18233.3 %
67471.4 %
2773.6 %
0.0 %
63.2 %
36202.9 %
0.0 %
77172.7 %
0.0 %
4424679.0 %
4.6 %
0.0 %
41.7 %
     As, Cd, Cu, Hg, and Ni are the same as for the S7-0, Table 8, case
above.   Slight  differences  are  due  to  stopping  the  convergence  at
slightly different places.  The difference between this case, S8-0, and
S7-0 (Table 8) above is that the organic FOC has been increased to 0.01
instead  of  0.0001.    This  should  increase  the  peak  retardation,
increasing the peak travel time, and tending to allow higher sludge dry
weight concentrations.
     Benzene: Travel time  has  been  increased  to 48 years, but is still
less  than  the  release  time  of  68  years.    Therefore,  the  peak
concentration, and therefore the allowable dry weight concentration, is
the same as the base case.
     B(A)P: Release time  is  still  the  same as for the S7-0 case above,
397,000 years,  but the travel  time has now  been  increased to 725,000
years  allowing  dispersion  to  reduce  the  peak and  allowing  somewhat
higher sludge concentrations.
     BEHP:  BEHP is vapor  controlled at  the dry weight concentration of
1600  mg/kg,  so  although   the  unsaturated  zone travel  time  has  been
increased by the  increase  in  retardation,  the total  peak concentration
has not been  significantly changed from the  previous  case.   Allowable
dry weight  concentrations  of BEHP  are  still  about 360  times  those of
the base case.
     Chlordane:  Travel time has been  increased  to  78,000 years,  but is
still  less  than the  release  time  of  105,000 years,   so  allowable dry
weight concentrations of Chlordane are unchanged from the base case.
                                   17

-------
     DDT:   The  increase   in   travel   time   to  400,000  years  allows
dispersion to significantly reduce the peak concentration from the base
case,  allowing  higher  sludge  concentrations.    The  vapor  pathway  is
becoming  dominant,   providing  .0085  mg/1  of  the  .0102 mg/1  health
effects level,  the  groundwater  pathway  providing  the  remaining .0017
mg/1.
     DMN:   The  very  low  Koc  of  0.04  for  DMN  provides very  little
velocity retardation  in  the unsaturated  zone,  so  raising the FOC from
.0001  to   .01  only   raises  the  Kd from  .000004 to  .0004.    This  has
essentially no  effect on  the  travel  time  of 14.6 years,  so the release
time of  23.9 years  still  controls  and  the peak  concentration  is  not
reduced.
     Lindane: The increase  in  FOC  increases  the travel  time  of Lindane
from 7.4  years for case  S7-0 to  25.6  years  for this  case allowing
essentially  total  degradation  assuming  a decay  constant of  1.   This
allows essentially a limitless  inventory of Lindane in the landfill.
     PCB:  Although the travel time has been increased from 50,000 years
to  160,000 years,  the  release  time  of  nearly 2,000,000 years  still
dominates, so  peak  outflow concentrations  are unchanged and allowable
dry weight concentrations are unchanged.
     TCE:   Travel  time  is  increased from  25 years  to  110 years,  but  is
still  below  the  release  time of  1000  years,  so  allowable  dry  weight
concentrations  are unchanged.
     Toxaphene:  The  travel  time  has   been   increased   to   135  years
compared with the release  time  of 89 years,  so dispersion is beginning
to  reduce  the  peak  concentration  entering the saturated zone, allowing
for 42% higher  dry weight concentrations in the sludge.
                                   18

-------
                               Table 10.

                  The Effects of Increasing Depth to
                    Groundwater from 0 to 5 meters.
 S9-0,  D=5M,  DIST=OM,  FOC=10-4,  R=0.5M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
2.89E+00
5.70E-01
6.00E+02
8.51E+01
2.36E+00
9.98E+01
2.75E-01
9.67E+01
1.62E+03
1.80E+02
2.09E+01
1.89E-03
1.44E+01
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
1345.0 %
1483.3 %
7042.9 %
24495.4 %
33614.3 %
1333.9 %
0.0 %
-0.1 %
35980.2 %
0.0 %
2109.3 %
0.0 %
537.2 %
4.6 %
0.0 %
0.0 %
     For this case,  the  depth  to groundwater has  been  reduced  from  10
meters for  the  previous  S7-0  (Table  8)  case to  5 meters.   One  would
expect generally lower allowable  sludge  dry  weight concentrations  than
for that  case,  but  still,  for  most  chemicals,  higher  concentrations
than for the  base  case.   This is exactly what is found.   Except  for
BEHP  and  Lindane,   all  chemicals  having higher  allowable  dry  weight
concentrations than  the base case  have  allowable  sludge  concentrations
for this case  about 1/2  those  for  the  S7-0  (Table 8) case, but  still
substantially  higher  than   the  base  case.    The  allowable   sludge
concentration for  BEHP is the  same for both  S7-0 and S9-0 cases  because
BEHP  is  vapor  controlled  at  this  sludge  concentration,  the  vapor
concentration  being   the   dominant   constituent   of  the   total
concentration.   The  allowable  sludge  concentration of Lindane  is  only
about   1/4   that  of  the   S7-0  case  because the   reduced  travel  time
increases  the outflow concentration exponentially.
                                  19

-------
                               Table 11.

   The Effects of Increasing Depth to Groundwater from 0 to 5 meters
       and  Increasing  Soil  Organic  Content  from  0.0001  to  0.01.

 S10-0, GW 5M, FOC 0.01, DIST OM, R 0.5 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9..00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
2.74E+00
5.72E-01
6.61E+02
8.53E+01
2.36E+00
9.98E+01
2.75E-01
1.08E+02
1.62E+03
1.80E+02
6.24E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.81E-01
% DIFFERENCE
1270.0 %
1488.9 %
7769.0 %
24553.2 %
33614.3 %
1333.9 %
0.0 %
11.6 %
35980.2 %
0.0 %
65862.0 %
0.0 %
4424679.0 %
4.6 %
0.0 %
5.8 %
     This case  is  the  same as the  S9-0  case  (Table  10)  except the FOC
has been  increased from 0.0001  to  0.01  increasing  retardation  in the
unsaturated zone.  This allows greater dispersion of the chemical plume
reducing  the   outflow  concentration   and  allowing   higher  sludge
concentrations.   One  would  expect,  then,  generally  higher  allowable
sludge concentrations  for  this case than for  the S9-0 case (Table 10).
This only applies to the organics,  however, so one should see no change
in the allowable metal  concentrations.
     This is what  is  found in the  results.   For the organics with un-
changed allowable  sludge  concentrations, the increase  in  travel times
have  been  insufficient  to   exceed  release  times,  so  peak  outflow
concentrations are still at leachate  levels.  The allowable dry weight
concentration  of  BEHP is  unchanged  from  the  S9-0  case  (Table  10)
because  it   is   still  vapor  controlled.    For   B(A)P  and  Toxaphene,
allowable sludge  concentrations  are  increased  over  the S9-0  and base
cases  because   the  travel   times have   been  increased  to  exceed  the
release  times.     For   DDT the   travel  time  has  been  substantially
increased over the release time  compared to the  S9-0 case  resulting in
significantly higher allowable sludge concentrations  than for that case
or  the  base  case.    The  increase  in  travel   time  for   Lindane  has
increased its allowable sludge concentration  almost  without bounds due
to its relatively high  decay rate of 1.
                                   20

-------
                               Table 12.

   The Effects of Increasing Depth to Groundwater from 0 to 1 meter.

 Sll-0,  GW 1M, DIST OM,  FOC 0.0001, R 0.5 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
5.64E-01
1.14E-01
1.52E+02
1.74E+01
4.73E-01
2.00E+01
2.75E-01
9.67E+01
1.57E+03
1.80E+02
4.28E+00
1.89E-03
3.44E+00
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
182.0 %
216.7 %
1709.5 %
4928.9 %
6657.1 %
187.4 %
0.0 %
-0.1 %
34866.6 %
0.0 %
352.4 %
0.0 %
52.2 %
4.6 %
0.0 %
0.0 %
     This  is  the  same  case  as  S9-0  (Table  10)  except  the  depth  to
groundwater has been reduced by a factor of 5 from 5 meters to 1 meter.
We see lower allowable dry  weight  concentrations because  there is less
dispersion in  the  unsaturated zone due to  shorter travel  times there.
All  chemicals  in  the S9-0  case  (Table 10) having unchanged allowable
sludge  concentrations   from  the  base   case   still   have  unchanged
concentrations  in  this  case.   All  chemicals  allowing  higher  sludge
concentrations  than  the  base case  in  case  S9-0  still   allow  higher
concentrations in this case, but at levels reduced by factors of from 4
to 7.  The only exceptions  are  BEHP,  which  is  unchanged  from the S9-0
case because it is still  vapor  controlled  due in part to its very high
Koc  of 2X10^,  and  Lindane,  which  is  reduced by  a factor of 10 from the
S9-0 case  due  to  the  exponential effects  of decay.   Since Lindane's
travel   time  is  reduced  from  5.6  to  1.8  years,  the  effects  of
degradation are exponentially reduced.
                                  21

-------
                               Table 13.

   The Effects of  Increasing Depth  to  Groundwater  from 0 to  1 meter
       and  Increasing Organic  Soil  Content  from  0.0001 to 0.01.

 S12-0,  GW 1M,  FOC 0.01, DIST OM, R 0.5 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
5.65E-01
1.14E-01
1.54E+02
1.71E+01
4.73E-01
2.00E+01
2.75E-01
9.68E+01
1.63E+03
1.80E+02
2.88E+02
1.89E-03
3.40E+03
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
182.5 %
216.7 %
1733.3 %
4842.2 %
6657.1 %
187.4 %
0.0 %
0.0 %
36202.9 %
0.0 %
30344.0 %
0.0 %
150342.5 %
4.6 %
0.0 %
0.0 %
     This case  and Sll-0  (Table 12) are  the  same except  the  FOC has
been increased from .0001  to  .01 for the organics.  This increases the
peak travel  time for retarded chemicals allowing greater dispersion and
allowing  generally greater  sludge  concentrations.    The  metals  are
unchanged because  their Kd's are  unaffected.   Of  the  organics  in the
Sll-0 case (Table  12),  only three have  allowable sludge concentrations
significantly exceeding those of the base case.  The rest are unchanged
from the base case in  both the Sll-0 and S12-0 cases (Tables 12 and 13,
respectively) because  the  travel  times  are  still  less  than  the release
times  allowing  the  peak  concentration  to  overpower  the  effects  of
dispersion in  the unsaturated  zone.   Of  the three organics  showing
increased allowable dry weight  concentrations over the  base  case, two
of them, DDT  and Lindane, show significantly increased allowable sludge
concentrations in  the  S12-0 case compared with  the  Sll-0  case because
the  travel  times  allow greater dispersion  in  the case  of  DDT,  and
greater dispersion and  degradation in the  case of Lindane.   BEHP shows
the  same  increased allowable sludge concentrations in  both  the Sll-0
and  S12-0 cases  because  it is   vapor controlled  due to the  very  high
unsaturated  zone travel  time of 2X10' years caused by the very high Koc
of 2X109.
                                   22

-------
                               Table 14.

    The Effects of Increasing the Depth to Groundwater from 0 to 10
       Meters,   and Decreasing  Recharge  from  0.5  m/y  to 0.25  m/y.

 S7-OR1, D to GW=10M, DIST=OM,  FOC=10-4, R=0.25M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
3.43E+00
1.07E+00
1.39E+03
1.60E+02
4.44E+00
1.87E+02
2.75E-01
9.69E+01
1.62E+03
1.80E+02
3.85E+01
1.89E-03
4.90E+02
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
1615.0 %
2872.2 %
16477.6 %
46142.0 %
63328.4 %
2586.2 %
0.0 %
-0.1 %
35980.2 %
0.0 %
3969.9 %
0.0 %
21581.4 %
4.6 %
0.0 %
0.0 %
     The chemicals which  have  no  change  from the base case have travel
times shorter than their  release  times.   Dispersion in the unsaturated
zone  therefore   has   insufficient  time   to   reduce   the   leachate
concentration.   The  4.6% increase  in PCB  concentrations  over the base
case is judged  insignificant.   The other chemicals, with significantly
greater allowable  sludge concentrations  than  the  base  case,  all  have
travel   times exceeding  their  release   times,  allowing  dispersion  to
reduce leachate concentrations in the unsaturated zone.  The higher the
ratio of travel  time to release  time, the higher the allowable sludge
concentration in  the landfill.   Therefore, the  chemicals  with higher
Kd's tend  to have the higher  allowable  sludge  concentrations compared
with their  base  case values.   BEHP has  a very  high  Kd  of 200,000 for
this case,  but  is vapor  controlled at  high sludge concentrations,  so
its allowable concentration is about equal to those of lead and mercury
with Kd's of  234  and  322.   Lindane has  a relatively small Kd of 0.108,
but the  travel time of 9.2 years  in the unsaturated zone allows about a
9000  fold  decrease  in  concentration  due  to  degradation,  so  the
allowable sludge concentrations are increased markedly.
     For most of the chemicals, there is a slight decrease in allowable
sludge  dry weight concentrations  as compared to the S7-0 case (Table 8)
with 0.5  m/y recharge.   The  reason  for  the change  is  that  when the
recharge  is  halved  from 0.5  m/y  to  0.25  m/y, the  release  time  is
doubled  given  the same  inventory,  but  the travel  time is  not  quite
                                   23

-------
doubled.  The  relation SLUDGEMAN uses for  calculating  travel  time for
water in the unsaturated zone is

  travel time = d*t*(R/K)**(l/(2b+3)/R

where d = depth to groundwater (m)
      t = unsaturated zone porosity
      R = recharge rate (m/y)
      K = saturated hydraulic conductivity
          for the unsaturated zone material
      b = "b"  value,  or  slope  of the log-log plot of matrix potential
          versus moisture content.

So, for this case,

     travel  time = 10*0.39*(0.25/10000)**(l/2*4+3)/0.25 = 5.95 years

compared with 3.17 years  for the 0.5 m/y recharge case.  Thus, halving
the recharge does not quite  double the travel time.
     If the release time  were  doubled and the travel  time doubled, the
plume  dynamics  would  remain   constant   relative  to   the  effects  of
dispersion  as  simulated  in  SLUDGEMAN, and the outflow concentration at
the  saturated  zone would remain constant.   However,  since  the travel
time is not quite  doubled,  dispersion has a little less time to reduce
the  peak  concentration in the plume,  and  the  outflow concentration is
raised. This requires  a slightly lower sludge concentration in order to
reduce  the  release time  and keep  the ratio of  travel  time  to release
time constant.
     Two  chemicals  whose   allowable  sludge  concentrations  are  not
reduced relative to the  S7-0 case  (Table 8) with 0.5 m/y recharge, are
BEHP  and   Lindane.     BEHP  is   vapor  controlled  at  a  dry  weight
concentration  of  1600 mg/kg,   so  the  unsaturated zone  dynamics  have
little effect.  The increase in  travel time due  to halving the recharge
allows much greater degradation  of Lindane, allowing an 8-fold increase
in sludge dry weight concentration.
                                   24

-------
                               Table 15.

        The  Combined Effects of Increased Depth to Groundwater,
         Increased Soil  Organic Content,  and Reduced Recharge.

 S8-OR1,  D to  GW=10M,  DIST=OM,  FOC=10-2,  R=0.25M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
3.43E+00
1.07E+00
1.39E+03
1.60E+02
4.44E+00
1.87E+02
2.75E-01
1.51E+02
1.63E+03
1.80E+02
7.22E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
4.91E-01
% DIFFERENCE
1615.0 %
2872.2 %
16477.6 %
46142.0 %
63328.4 %
2586.2 %
0.0 %
56.0 %
36202.9 %
0.0 %
76221.7 %
0.0 %
4424679.0 %
4.6 %
0.0 %
36.4 %
     This case is nearly  identical  to  the  S8-0 case (Table 9) with 0.5
m/y recharge.  The comments  describing  the results  for the S7-OR1 case
(Table 14)  above apply here.   The 0.25 m/y recharge doubles the release
time  given   the  same  inventory  and  leachate  concentration,  but  the
travel time does not quite double, so most of the chemicals with higher
allowable  concentrations  than  the  base  case  have  slightly  lower
allowable concentrations  at  0.25  m/y  than  at  0.5  m/y recharge.   The
exceptions   are  BEHP  which   is   vapor  controlled  at  these  sludge
concentrations, and Lindane,  which degrades significantly more with the
increased travel  time.
                                  25

-------
                               Table 16.

   The Effects of Increasing Depth to Groundwater from 0 to 5 Meters
            and Reducing Recharge from 0.5 m/y to 0.25 m/y.

 S9-OR1,  D=5M, DIST=OM, FOC=10-4, R=0.25M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
1.70E+00
5.37E-01
7.05E+02
8.02E+01
2.22E+00
9.33E+01
2.75E-01
9.67E+01
1.62E+03
1.80E+02
1.96E+01
1.89E-03
5.23E+01
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
750.0 %
1391.7 %
8292.9 %
23079.4 %
31614.3 %
1240.5 %
0.0 %
-0.1 %
35980.2 %
0.0 %
1971.9 %
0.0 %
2214.2 %
4.6 %
0.0 %
0.0 %
     This  is  the  same  situation  as  for  the  S7-OR1 and  S8-OR1  cases
above (Tables  14  and 15,  respectively).   Those chemicals  not  changed
from the base case have  travel  times  less than their release times, so
that  the  outflow concentration  into   the  saturated  zone  comes  to
equilibrium at  the leachate  concentration.    Chemicals with  allowable
sludge concentrations above the  base  case are  generally little  changed
from  the  S9-0  case  (Table  10)  with  0.5  m/y recharge  because  the
decrease in recharge increases the release time but  also  increases the
travel time  by nearly  the same amount.   So,  the plume dynamics  with
regard to dispersion  remain nearly constant.  Travel  times  for the peak
concentrations  are nearly doubled,  but  the   peaks  are   at  the  same
concentrations as  for the  0.5 m/y recharge  case.   Lindane's  allowable
sludge concentration  is about 4  times higher than  that  for the  0.5 m/y
recharge case due to  greater degradation during the longer  travel  time.
                                  26

-------
                               Table 17.

  The Combined Effects of Increasing Depth to Groundwater from 0 to 5
     Meters,  Increasing  Soil  Organic Content  from  0.0001  to  0.01,
            and Reducing Recharge from 0.5 m/y to 0.25 m/y.

 S10-OR1, D=5M, DIST=OM, FOC=10-2, R=0.25M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
1.70E+00
5.37E-01
7.05E+02
8.02E+01
2.22E+00
9.33E+01
2.75E-01
1.06E+02
1.63E+03
1.80E+02
6.12E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.75E-01
% DIFFERENCE
750.0 %
1391.7 %
8292.9 %
23079.4 %
31614.3 %
1240.5 %
0.0 %
9.5 %
36202.2 %
0.0 %
64593.4 %
0.0 %
4424579.0 %
4.6 %
0.0 %
4.2 %
     The S10 case  is  the  same as the S9 case except that the Foe's for
the organics have  been  increased from 0.0001 to 0.01.   So, the results
for the  metals  remain unchanged.   Allowable dry weight concentrations
of  B(A)P and Toxaphene  have  slipped  above the  0  level  due  to  their
travel times  edging  just  above their  release  times.   Otherwise,  the
chemicals with  unchanged  allowable  dry  weight  concentrations compared
to  the  base  case  are still  unchanged.    BEHP  is still  essentially
unchanged   from   the  S9-OR1   case  (Table  16)   because   its   vapor
concentration   is   still   its   dominant  influence   at   this   sludge
concentration.    DDT  shows  a marked  increase  in its  allowable  sludge
concentration due  to  the  100-fold  increase  in  its travel  time allowing
dispersion to significantly  reduce its  peak concentration.   Increasing
Lindane's Kd  from  .108 to  10.8 has  increased  its  travel time to  the
point  where  degradation   is  so  great  that   even   with   a  sludge
concentration of 100,000 mg/kg, we only see an outflow concentration of
lO'll   mg/1.    So,   Lindane's  allowable  sludge  concentration has  been
greatly increased by the increased retardation in the unsaturated  zone.
                                   27

-------
                               Table 18.

   The Effects  of  Increasing  Depth  to  Groundwater  from  0  to  1  Meter
           while Reducing Recharge from 0.5 m/y to 0.25 m/y.

 S11-OR1, GW 1M, DIST OM, FOC 0.0001, R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
5.29E-01
1.07E-01
1.48E+02
1.60E+01
4.44E-01
1.87E+01
2.75E-01
9.67E+01
1.57E+03
1.80E+02
4.03E+00
1.89E-03
4.86E+00
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
164.5 %
197.2 %
1661.9 %
4524.3 %
6242.9 %
168.7 %
0.0 %
-0.1 %
34866.6 %
0.0 %
326.0 %
0.0 %
115.0 %
4.6 %
0.0 %
0.0 %
     This is really  the  same  case as the S7-OR1 case above (Table 14),
but  with all  allowable  dry  weight  concentrations  scaled  down  by  a
factor of  10 due to  the depth to groundwater  being  one-tenth that in
the  earlier case  (1  m  vs   10  m).    Cadmium's  allowable dry  weight
concentration,  for example, is  197%  greater than for the base case, or
2.97 times  greater  (.107  mg/kg vs  .0036  mg/kg).   In  the  S7-OR1  case
(Table  14),  cadmium's  allowable  was  2872%  higher  or  29.72  times
greater.   Some chemicals  vary from this 10 to 1 rule somewhat, but not
by amounts  that  are  numerically significant.   For  example,  copper has
an allowable for this case of 148 mg/kg compared to 1390 for the S7-OR1
case.  This is  a ratio of  .1065.
     The  biggest  difference  is  seen  in  the  results for  arsenic.   In
this case,  the  allowable  is  .529 and  for  the  S7-OR1  case it is  3.43
mg/kg,  a ratio  of  0.154.   But  arsenic  is  an especially  difficult
chemical  for  which  to  estimate  allowable  dry  weight  concentrations.
This is  due to  difficulties  encountered  when  interpolating  the MINTEQ
data to  simulate  the effects  of sorption  in  the saturated zone due to
the eh/ph there.   One difficulty is trying to obtain a  concentration in
the saturated zone equal  to the health  effects  level  of 0.05 mg/1 for
arsenic by finding a  value  between  0.06 mg/1  and 1.27  mg/1 that yields
0.05  mg/1   when   interpolated  between  0.00024  mg/1  and  1.06  mg/1
respectively.    A  value of  0.12  is  about  right,  but  when  SLUDGEMAN
attacks the  problem with, say, 0.06 and obtains a result of 0.00024, it
tries  increasing  the dry  weight  concentration  by  about  100,  to  get
                                   28

-------
closer to  the  0.05 it wants.   This  produces  a  concentration entering
the saturated  zone of about  6,  which after sorption  results in about
5.3.  Then  SLUDGEMAN  reduces this by  about  100  to  try to achieve 0.05
and gets  back  to  the 0.06  with  which it started.   Thus  SLUDGEMAN can
oscillate between two values.
     At this point,  the  user can edit a  dry weight concentration into
the SLUDGIN.OUT file that lies between the  extremes SLUDGEMAN has been
attempting.  We  have found  this  to help on occasion,  but  not always.
Often SLUDGEMAN goes back to  bouncing between  the limits  it previously
chose.   Presumably in such  cases,  slight variations  in  input produce
widely varying results,  due to the  interpolation,  and  one  chooses the
lower sludge concentration  to be conservative.   In  the cases in which
SLUDGEMAN  has  oscillated  like  this,  however,  we   have  not  seen  the
oscillations over  a greater  range  than 3  to 1.  So, in our experience,
the oscillations  have  been  much  less  than  the 100  to  1 range depicted
in the example above.
     As  mentioned, most  of the  S11-OR1  results  (Table  18)  are just
about  10%  of  those  for  the S7-OR1  case  (Table   14).    Two notable
exceptions  are BEHP  and Lindane.   As  in  the  previous  examples,  the
reasons  are  that  BEHP   is  still  vapor  controlled  at  these   sludge
concentrations although  the groundwater  concentration  is  becoming more
important  with the  shallower groundwater,  and   Lindane  degrades much
less due  to the  shorter  travel  time in the shorter  1 meter unsaturated
zone.
                                   29

-------
                               Table 19.

  The  Combined Effects of Increasing Depth to Groundwater from 0 to 1
    Meter,  Increasing Soil  Organic Content from 0.0001  to 0.01,  and
              Reducing Recharge from 0.5  m/y to 0.25 m/y.

 S12-OR1,  GW 1M,  DIST OM, FOC 0.01, R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
5.29E-01
1.07E-01
1.48E+02
1.60E+01
4.44E-01
1.87E+01
2.75E-01
9.67E+01
1.63E+03
1.80E+02
2.76E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
164.5 %
197.2 %
1661.9 %
4524.3 %
6242.9 %
168.7 %
0.0 %
-0.1 %
36202.9 %
0.0 %
29075.5 %
0.0 %
4424579.0 %
4.6 %
0.0 %
0.0 %
     The explanation  of  these results  is  the same as  for  the  S10-OR1
and  S8-OR1   cases  (Tables  17  and  15,  respectively).     The  metal
concentrations  are   unchanged  because  the  increase  in  Foe  has  not
affected  them.    Organics  unchanged  from  the   base   case  are  still
unchanged because their travel times  are  still less  than  their  release
times.   BEHP  is  unchanged from the S11-OR1  case  (Table 18)  because it
is vapor controlled and retardation in  the  unsaturated  zone  has little
effect.   The allowable sludge concentration of DDT is increased  because
the increase  in  Kd  has increased  the travel time  substantially  (from
900 years  to  75,000 years)  allowing  dispersion  to  reduce the  peak
concentration and  allowing greater sludge  input concentrations.   The
allowable sludge  concentration  of Lindane  is  increased because  the
increase in  retardation has  increased its travel time  from  3.05  years
for  the  S11-OR1   case  to  10.2  years  for  this  case  resulting  in
substantially greater degradation and  more dispersion.
                                  30

-------
                               Table 20.

  The Effects of  Increasing  Depth  to  Groundwater  from  0  to  10 Meters
    while Significantly  Reducing Recharge  from  0.5  to  0.00635 m/y.

S7-OR2,  D to GW=10M, DIST=OM,, FOC=10-4, R=0.00635M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
3.06E+00
7.69E-01
1.06E+03
1.15E+02
3.18E+00
1.34E+02
2.75E-01
9.68E+01
1.62E+03
1.80E+02
2.78E+01
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
1430.0 %
2036.1 %
12519.0 %
33137.0 %
45328.4 %
1825.2 %
0.0 %
0.0 %
35980.9 %
0.0 %
2838.7 %
0.0 %
4424679.0 %
4.6 %
0.0 %
0.0 %
     TKese results  are nearly  identical  with  as those  for  the S7-OR1
case  (Table   14),  so  the  comments  for  that  case apply  here.    The
unchanged  values   have  release  times   exceeding  travel   times  so
dispersion is  ineffective  in  reducing  peak concentrations.   Dispersion
only increases travel time for the peak.  For those values changed from
the base case, their  travel times  exceed  their release times,  allowing
dispersion to  reduce their outflow  concentrations  and allowing higher
sludge  concentrations  in the  landfill.    BEHP  is  vapor  controlled  at
this  concentration,   so  groundwater  changes   have little  effect  on
allowable concentrations.   The lower recharge of 0.00635 m/y  for this
case compared with 0.25 m/y for the S7-OR1 case causes a greater travel
time  through  the  unsaturated  zone  for all  the  chemicals.    This
significantly  increases the  allowable dry  weight concentrations  for
Lindane  due   to   its  decay  rate  of  1.    The  other  chemicals,  with
allowable sludge  concentrations greater  than  those of  the  base  case,
have somewhat  lower allowable  dry  weight concentrations in  this case
than  in the  S7-OR1   and  S7-0  cases  (Tables  14  and  8,  respectively)
because  the   travel   times  are  not  increased  proportionally to  the
decrease in  recharge  rate.   Therefore, the  greater effects  of disper-
sion do not  cancel the  effects  of  longer  release time, necessitating a
reduction in release  time  and  therefore lower  sludge  concentration.
This is more  fully explained in the comments concerning the S7-OR1 case
above (Table  14).
                                  31

-------
                               Table 21.

 The Combined Effects of  Increasing Depth to Groundwater  from 0 to  10
   Meters,  Increasing Soil Organic Content  from 0.0001 to 0.01, and
     Reducing Recharge  significantly  from 0.5 m/y to 0.00635 m/y.

S8-OR2,  D to GW=10M, DIST=OM, FOC=10-2, R=0.00635M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
3.07E+00
7.69E-01
1.06E+03
1.15E+02
3.18E+00
1.34E+02
2.75E-01
1.23E+02
1.63E+03
1.80E+02
6.74E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
4.13E-01
% DIFFERENCE
1435.0 %
2036.1 %
12519.0 %
33137.0 %
45328.4 %
1825.3 %
0.0 %
27.1 %
36202.9 %
0.0 %
71147.4 %
0.0 %
4424679.0 %
4.6 %
0.0 %
14.7 %
     The results for this case are nearly identical to those of the
S8-OR1 and S8-0 cases discussed  above  (Tables  15 and 9,  respectively).
Retardation  in  the  unsaturated  zone  allows  dispersion  to  reduce the
peak concentrations  for most  of  the  chemicals.   This is  true for those
with allowable  sludge concentrations  exceeding  their base  case values.
For the unchanged chemicals, their unsaturated zone travel  times do not
exceed their  release times,  so dispersion  has insufficient  room and
time to reduce their peak concentrations.   The  peak concentrations for
such chemicals enter the saturated zone at a later time than in the S8-
OR1, S8-0, and  base cases,   but  the  peak concentrations are the same.
BEHP is vapor controlled at  this concentration,  so its allowable sludge
dry weight  concentration remains  unchanged from  the S8-0  and  S8-OR1
cases   (Tables  9  and  15,   respectively).    The  allowable   dry  weight
concentration for Lindane is set at a ceiling value of 105  mg/kg due to
the tremendous degradation occurring  over its increased travel time for
this case.
                                  32

-------
                               Table 22.

   The Effects of Increasing Depth to Groundwater from 0 to 5 Meters
    while Significantly  Reducing  Recharge  from  0.5  to  0.00635 m/y.

 S9-OR2,  D=5M, DIST=OM, FOC=10-4,  R=0.00635M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
1.49E+00
3.84E-01
4.99E+02
5.74E+01
1.59E+00
6.68E+01
2.75E-01
9.67E+01
1.61E+03
1.80E+02
1.41E+01
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
645.0 %
966.7 %
5840.5 %
16489.4 %
22614.3 %
859.8 %
0.0 %
-0.1 %
35757.5 %
0.0 %
1390.4 %
0.0 %
4424679.0 %
4.6 %
0.0 %
0.0 %
     The results for this case are nearly identical to those of the
S9-OR1 and S9-0 cases discussed above (Tables 16 and 10, respectively).
Retardation  in  the  unsaturated  zone allows  dispersion to  reduce the
peak concentrations  for most  of  the  chemicals.   This is true for those
with allowable  sludge  concentrations exceeding  their base case values.
For the unchanged chemicals, their unsaturated zone travel times do not
exceed their release  times,  so dispersion  has insufficient  room and
time to reduce  their peak  concentrations.   The  peak concentrations for
such chemicals enter the saturated zone at a later time than in the S9-
OR1, S9-0,  and  base cases,  but  the  peak concentrations  are the same.
BEHP is vapor controlled at this concentration,  so its allowable sludge
dry weight  concentration  remains  unchanged from  the S9-0  and S9-OR1
cases (Tables 10 and 16, respectively).
     The allowable  dry weight  concentration  for  Lindane  is set  at  a
ceiling value of 105 mg/kg  due  to  the  tremendous degradation occurring
over its increased travel  time for this  case.   Lindane's degradation is
much higher  for this case  than  for  the S9-OR1  and  S9-0  cases  because
the decreased   recharge  has  significantly  increased  the travel  time
through the unsaturated zone allowing much greater degradation.
                                  33

-------
                               Table 23.

  The Combined Effects of Increasing Depth to Groundwater from 0 to 5
   Meters,  Increasing  Soil  Organic  Content  from  0.0001  to 0.01,  and
      Reducing  Recharge significantly  from 0.5 m/y  to  0.00635  m/y.
 S10-OR2, D=5M, DIST=OM, FOC=10-2, R=0.00635M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
J.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
1.37E+00
3.84E-01
4.99E+02
5.74E+01
1.59E+00
6.68E+01
2.75E-01
9.92E+01
1.63E+03
1.80E+02
5.46E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
585.0 %
966.7 %
5840.5 %
16489.4 %
22614.3 %
859.8 %
0.0 %
2.5 %
36202.2 %
0.0 %
57616.4 %
0.0 %
4424679.0 %
4.6 %
0.0 %
0.0 %
     These results  are  nearly identical with as  those  for the S10-OR1
case  (Table   17),   so  the  comments   for  that  case apply  here.    The
unchanged  values   have  release  times   exceeding  travel   times  so
dispersion is  ineffective  in  reducing peak concentrations.  Dispersion
only increases travel time for the peak.  For those values changed from
the base case, their  travel  times  exceed  their  release times,  allowing
dispersion to  reduce their outflow  concentrations  and  allowing higher
sludge  concentrations  in the  landfill.   BEHP  is  vapor  controlled  at
this  concentration,  so  groundwater  changes  have little  effect  on
allowable concentrations.   The lower recharge  of 0.00635  m/y  for this
case  compared  with  0.25 m/y  for the  S10-OR1   case  causes a greater
travel time through the unsaturated  zone for all the  chemicals.   This
significantly  increases the  allowable dry  weight concentrations  for
Lindane  due   to  its  decay  rate  of  1.    The   other  chemicals,  with
allowable sludge  concentrations  greater  than  those of the  base  case,
have somewhat  lower allowable dry weight concentrations  in this  case
than in  the  S10-OR1 and S10-0  cases (Tables 17  and  11,  respectively)
because  the   travel  times  are  not   increased   proportionally to  the
decrease in recharge  rate.   Therefore,  the greater effects  of disper-
sion do  not  cancel  the longer release time,   necessitating a shorter
release time  and  therefore  lower sludge  concentration.    This  is  more
fully  explained in  the comments for the S7-OR1 case  above (Table 14).
                                  34

-------
                               Table 24.
   The Effects  of  Increasing  Depth  to  Groundwater  from  0  to  1 Meter
    while Significantly  Reducing  Recharge  from  0.5 to 0.00635 m/y.

 S11-OR2,  D=1M,  DIST=OM,  FOC=10-4, R=0.00635M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
3.16E-01
7.68E-02
1.05E+02
1.15E+01
3.18E-01
1.34E+01
2.75E-01
9.67E+01
1.54E+03
1.80E+02
2.97E+00
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
58.0 %
113.3 %
1150.0 %
3223.7 %
4442.9 %
92.5 %
0.0 %
-0.1 %
34198.2 %
0.0 %
214.0 %
0.0 %
4424679.0 %
4.6 %
0.0 %
0.0 %
     These results are nearly identical with those for the S11-OR1 case
(Table 18),  so  the comments  for  that case apply  here.   The unchanged
values  have  release  times  exceeding  travel  times  so dispersion  is
ineffective in  reducing peak concentrations.  Dispersion only increases
travel time for the peak.  For those values changed from the base case,
their travel times  exceed their release  times,  allowing  dispersion  to
reduce  their   outflow  concentrations   and   allowing   higher  sludge
concentrations   in  the  landfill.    BEHP  is vapor  controlled at  this
                so  groundwater changes have little  effect  on allowable
                  The  lower  recharge  of  0.00635  m/y  for this  case
               0.25 m/y  for  the S11-OR1  case  causes a  greater  travel
               the   unsaturated  zone   for  all  the  chemicals.    This
               increases  the  allowable dry weight  concentrations  for
                 its  decay  rate  of  1.    The  other  chemicals,  with
                  concentrations greater  than  those of the  base case,
concentration,
concentrations,
compared with
time  through
significantly
Lindane  due  to
allowable sludge
have somewhat  lower
than in the  S11-OR1
because the  travel
decrease in recharge
sion do not  cancel
                     allowable dry  weight  concentrations in  this  case
                     and Sll-0  cases  (Tables 18  and  12,  respectively)
                     times  are  not  increased  proportionally  to  the
                     rate.   Therefore,  the greater effects  of  disper-
                    the  longer release  time,  necessitating  a  shorter
release time  and  therefore lower  sludge  concentration.
fully explained in the comments for the S7-OR1 case above
                                                          This  is  more
                                                          (Table 14).
                                  35

-------
                               Table 25.

  The Combined Effects of Increasing Depth to Groundwater from 0 to 1
    Meter, Increasing Soil Organic Content from 0.0001 to 0.01, and
      Reducing  Recharge  significantly from 0.5  m/y  to  0.00635  m/y.
 S12-OR2, D=1M, DIST=OM, FOC=10-2, R=0.00635M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
9.00E-03
1.12E+00
5.14E-02
1.65E-03
1.75E+00
5.00E-03
3.00E-04
2.44E-01
2.09E-03
1.02E-02
9.73E-05
4.00E-03
4.09E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.00E-01
3.60E-02
8.40E+00
3.46E-01
7.00E-03
6.96E+00
2.75E-01
9.68E+01
4.49E+00
1.80E+02
9.46E-01
1.89E-03
2.26E+00
6.30E+02
4.06E+00
3.60E-01
3.32E-01
7.68E-02
1.05E+02
1.15E+01
3.18E-01
1.34E+01
2.75E-01
9.92E+01
1.63E+03
1.80E+02
2.17E+02
1.89E-03
l.OOE+05
6.59E+02
4.06E+00
3.60E-01
% DIFFERENCE
66.0 %
113.3 %
1150.0 %
3223.7 %
4442.9 %
92.5 %
0.0 %
2.5 %
36202.2 %
0.0 %
22838.7 %
0.0 %
4424679.0 %
4.6 %
0.0 %
0.0 %
     These results  are  nearly identical with as  those  for the S12-OR1
case  (Table   19),   so  the  comments  for  that  case apply  here.    The
unchanged  values   have  release  times   exceeding  travel   times  so
dispersion is  ineffective in  reducing  peak concentrations.  Dispersion
only increases travel time for the peak.  For those values changed from
the base case, their  travel times  exceed  their  release times,  allowing
dispersion to  reduce their outflow  concentrations  and  allowing higher
sludge concentrations  in the  landfill.   BEHP  is  vapor  controlled  at
this  concentration,  so  groundwater  changes  have little  effect  on
allowable concentrations.   The lower recharge of 0.00635  m/y  for this
case  compared with  0.25 m/y  for the  S12-OR1   case  causes a greater
travel time through the unsat- urated zone for all the chemicals.   This
significantly  increases  the  allowable dry  weight concentrations  for
Lindane  due   to   its  decay  rate  of  1.    The   other  chemicals,  with
allowable sludge  concentrations greater  than those of the  base  case,
have  somewhat  lower allowable  dry weight concentrations  in  this case
than  in  the  S12-OR1 and  S12-0 cases (Tables 19  and  13,  respectively)
because  the   travel   times  -are  not  increased   proportionally to  the
decrease  in recharge  rate.   Therefore, the  greater effects  of disper-
sion do  not  cancel  the longer  release time, necessitating  a shorter
release time  and  therefore lower  sludge  concentration.    This  is more
fully explained in the comments for the S7-OR1 case above (Table 14).
                                   36

-------
                              Table 26.



          Base Case  for  Well  150  Meters  from  the  Boundary.



B4 150 -- Base Case
Concentrations in mg/1.



CHEMICAL     AQUIFER   VAPOR    BCKGRND     SUM
HEL
CS
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
4
8
1
1
5
1
5
3
2
1
1
0
4
3
5
5
.92E-02
.93E-03
.OOE+00
.59E-02
.37E-03
.OOE+00
.OOE-03
.OOE-04
.43E-01
.07E-07
.OOE-02
.OOE+00
.OOE-03
.53E-04
.OOE-03
.OOE-03
0
0
0
0
0
0
0
9
2
1
1
1
0
1
0
0
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.90E-12
.12E-03
.38E-04
.99E-04
.OOE-04
.OOE+00
.01E-04
.OOE+00
.OOE+00
4
1
1
1
3
2
0
0
0
0
0
0
0
0
0
0
.OOE-04
.OOE-03
.OOE-02
.OOE-03
.OOE-04
.70E-03
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
.OOE+00
4
9
1
1
8
1
5
3
2
1
1
1
4
4
5
5
.96E-02
.93E-03
.01E+00
.69E-02
.37E-04
.03E+00
.OOE-03
.OOE-04
.45E-01
.38E-04
.02E-02
.OOE-04
.OOE-03
.54E-04
.OOE-03
.OOE-03
5.
1.
1.
5.
2.
1.
5.
3.
2.
2.
1.
1.
4.
4.
5.
5.
OOE-02
OOE-02
30E+00
OOE-02
OOE-03
75E+00
OOE-03
OOE-04
45E-01
10E-03
02E-02
OOE-04
OOE-03
54E-04
OOE-03
OOE-03
2.40E+01
9.44E+00
l.OOE+04
5.08E+02
2.36E+01
1.00E+.04
8.50E-01
2.50E+02
1.39E+01
l.OOE+04
1.72E+01
7.01E-W
4.92E+01
1.47E+03
5.14E+01
1.11E+00
                                  37

-------
                               Table 27.

  The Effects of Increasing Depth to Groundwater from 0 to 10 Meters.

 S7_150,  D to GW=10M, DIST=150 M, FOC=10-4, R=0.5M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5816E+01
1.6935E+01
l.OOOOE+04
1.4406E+03
6.5761E+01
l.OOOOE+04
8.4983E-01
2.5007E+02
1.6298E+03
l.OOOOE+04
3.3527E+02
7.0109E-02
1.3429E+03
1.4717E+03
5.1357E+01
1.1132E+00
% DIFFERENCE
49.7 %
79.4 %
0.0 %
183.7 %
179.2 %
0.0 %
0.0 %
0.0 %
11583.2 %
0.0 %
1850.0 %
0.0 %
2630.0 %
-0.1 %
0.0 %
0.2 %
     The chemicals
times so long that
saturated zones is  insufficient
that obtained in the  base  case,
so short in comparison with  the
no impact on  the  final  concentration.   The  two
Chlordane and  DMN,  which  are  vapor  controlled
 unchanged  from  the  base case  either have  release
the combined dispersion  in  both  the  unsaturated  and
             to reduce the  peak  concentration  below
             or the  unsaturated  zone  travel  time is
             total travel time  as  to  have  virtually
                             exceptions to this  are
                             in  both  cases  so that
depth to groundwater  has  no effect on  final  concentration.   DMN is an
interesting case because  degradation  in the  saturated  zone  is  so high
that all of the final  concentration  is  attributable to the vapor path-
way.
     Chemicals with allowable  dry  weight  concentrations above the base
case generally have total travel times  long enough that dispersion can
reduce the peak concentration  and  allow higher initial concentrations.
The  one exception  here  is  Lindane,  which  benefits not  only  from
additional  dispersion in the unsaturated zone, but also from additional
degradation.
                                  38

-------
                               Table 28.

  The Effects of  Increasing Depth to Groundwater from 0 to  10 Meters
    and  Reducing Recharge from 0.5 to 0.25 m/y at a 150  Meter Well.

 S7-150R1,  GW 10M, D 150M,  R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5205E+01
1.7484E+01
l.OOOOE+04
1.4426E+03
6.5003E+01
l.OOOOE+04
1.6997E+00
5.0033E+02
1.6309E+03
l.OOOOE+04
4.7181E+02
7.0109E-02
l.OOOOE+04
2.4051E+03
1.0271E+02
1.8619E+00
% DIFFERENCE
47.2 %
85.2 %
0.0 %
184.1 %
176.0 %
0.0 %
100.0 %
100.0 %
11591.0 %
0.0 %
2644.2 %
0.0 %
20228.9 %
63.3 %
100.0 %
67.6 %
     The reduced recharge levels decrease unsaturated zone travel  times
while increasing pulse times.  More importantly, they reduce the annual
flux to the  saturated  zone  so there  is  less  contaminant  to be diluted
by  the  aquifer.     The   effects   are  minimal  for  the  metals  since
geochemistry  effects  outweigh  dilution.    Conversely,   the  organic
contaminants  are  greatly  affected.   As  a  consequence,   much  higher
sludge  concentrations  can   be  accepted.    Chlordane   and  DMN  remain
exceptions because their  risk levels are driven by vapor considerations
rather than ground water transport.   The greater  travel  time has  a big
effect on  Lindane since degradation  allows  for extremely  high  sludge
concentrations to be  mitigated.    The  copper and nickel  are  unchanged
because the  base  case  is already at the maximum  allowable  level  of
10,000 mg/kg.
                                  39

-------
                               Table 29.

  The Effects of Increasing Depth to Groundwater from 0 to  10 Meters
  and Reducing Recharge from 0.5 to 0.00635 m/y at a 150 Meter Well.

 S7-150R2,  GW 10M,  D 150M,  R 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.3432E+02
l.OOOOE+04
3.5669E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.4046E+02
7.0125E-02
l.OOOOE+04
6.2055E+03
2.5680E- *?
4.6715E+--1
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
2593.3 %
0.0 %
4097.1 %
3897.4 %
11596.1 %
0.0 %
4788.4 %
0.0 %
20228.9 %
321.3 %
4900.7 %
4104.0 %
     The combined  effect  of  increased  travel time  from the  greater
depth of  the unsaturated  zone  and  the  low  recharge creates  greatly
reduced   aquifer  concentrations  because  of  the  enhanced  dispersion,
greater  time for degradation,  and  smaller flux of  chemical  that needs
to be diluted by  the groundwater.  As a consequence, much higher sludge
concentrations  can  be  tolerated  with  four  exceptions:  copper,  nickel,
Chlordane,  and  DMN.  Copper  and  nickel  have the  maximum concentrations
already  allowed  in  the base case.   In the case of Chlordane  and  DMN,
vapor  considerations   dictate  the   risk   and,    hence,  the   sludge
concentrations.   Therefore,  changes  in  the  groundwater  pathway  have no
impact  on   criteria  levels.    The  large  effects  noted  for  those
contaminants whose  concentrations  do change  reflects  the predominance
of saturated zone impacts  on overall  system risks.
                                  40

-------
                               Table 30.

  The Effects of Increasing Depth to Groundwater from 0 to 10 Meters
             and  Aquifer Thickness from 15 to 78.6  Meters.

 S7-150T1,  D  to GW=10M,  FOC= 0-4,  D=150M,  AQ=78.6M,  R=0.5M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5816E+01
1.7494E+01
l.OOOOE+04
1.4557E+03
6.6544E+01
l.OOOOE+04
1.7631E+00
4.8870E+02
1.6298E+03
l.OOOOE+04
4.6579E+02
7.0109E-02
2.4416E+03
2.3724E+03
9.3717E+01
2.3095E+00
% DIFFERENCE
49.7 %
85.3 %
0.0 %
186.7 %
182.5 %
0.0 %
107.5 %
95.4 %
11583.2 %
0.0 %
2609.2 %
0.0 %
4863.5 %
61.1 %
82.5 %
107.8 %
     The  results  for  increased  depth  to groundwater  and  increased
aquifer  thickness  are almost  identical  to those for  the  greater  depth
but same aquifer thickness.   This suggests that the  base case aquifer
thickness  is  sufficiently  large  that   it  does not  inhibit  vertical
dispersion.     The  exceptions   are   B(A)P,   Benzene,   PCB,   TCE,   and
Toxaphene.    These  are  the  organics that  are not  driven  by  vapor
considerations   (BEHP,  Chlordane,  and DMN)  or degradation  (Lindane).
The  inorganics  are  controlled  by  geochemistry  and do  not  display
vertical  dispersion  restrictions  under  the   deeper  unsaturated  zone
conditions.   Copper  and Nickel  are  already  at the  maximum  allowable
concentrations  of  10,000 mg/kg.
                                  41

-------
                               Table 31.

   The  Effects  of Increased Depth to Groundwater from 0 to 10 Meters
          and Reduced Aquifer Thickness from  15 to  5 Meters.

 S7-150T2,  GW 10M,  FOC 10-4,  D 150M, AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.7096E+01
8.2636E+00
3.3560E+03
7.0874E+02
3.4037E+01
1.0049E+03
2.8347E-01
8.3400E+01
1.6187E+03
l.OOOOE+04
1.4963E+02
7.0114E-02
4.4835E+02
5.7529E+02
1.7044E+01
3.7113E-01
% DIFFERENCE
-28.5 %
-12.5 %
-66.4 %
39.6 %
44.5 %
-90.0 %
-66.6 %
-66.7 %
11503.6 %
0.0 %
770.3 %
0.0 %
811.4 %
-60.9 %
-66.8 %
-66.6 %
     The  reduced  aquifer  thickness  decreases  the space  available  for
vertical  dispersion and thereby keeps  the  plume  more  concentrated than
in the  base  case.   Therefore,  most allowable concentrations are smaller
than in  the  base case  even though  the larger  unsaturated  zone  would
normally  accommodate  higher sludge  concentrations as  in case  S7-150
(Table   27).     For  all   the   contaminants  with   negative   percent
differences,  the  saturated  zone  dispersion  effects  dominate  those  in
the unsaturated  zone.   For  mercury  and  lead,   the  unsaturated  zone
changes  override the  vertical  dispersion  effects  because geochemistry
controls  the groundwater  concentrations rather  than  dispersion.   For
Lindane,  the  added travel  time  in the  unsaturated  zone  allows  for
significant   degradation   and   overrides   the  loss   of  dispersion.
Chlordane and DMN concentrations  are unaffected  by the  aquifer changes
because the  risks  are  driven by  the vapor pathway.  Similarly,  the long
unsaturated  zone travel  time for  BEHP  makes  the  vapor pathway  dominant
and,  therefore, changes  in the  aquifer properties  have  no effect  on
allowable sludge levels.
                                  42

-------
                               Table 32.

          The  Effects  of Increased Depth to Groundwater and
                 Aquifer Thickness, Reduced Recharge.

 S7-150R1T1,  GW 10M,  D  150M,  R 0.25M/Y,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
4.2125E+01
1.7679E+01
l.OOOOE+04
1.5347E+03
7.0072E+01
l.OOOOE+04
3.5262E+00
9.7764E+02
1.6298E+03
l.OOOOE+04
5.9757E+02
7.0109E-02
l.OOOOE+04
3.4944E+03
1.8743E+02
3.6333E+00
% DIFFERENCE
76.1 %
87.2 %
0.0 %
202.2 %
197.5 %
0.0 %
314.9 %
290.8 %
11583.2 %
0.0 %
3375.7 %
0.0 %
20228.9 %
137.2 %
265.0 %
227.0 %
     This  case is  almost  identical to  S7-150  RI  (Table  28)  where  all
changes  were  the  same without the thickened aquifer.   The minor effects
that  occur are  noted with  the more  retarded  contaminants whose  slow
velocities  allow  time  for  vertical  dispersivity to be  significant.
This  illustrates  that for most  contaminants, the 15m aquifer  thickness
does  not constrain  dispersivity at 150 meters.
                                  43

-------
                               Table 33.

   The Effects of Increased Depth to Groundwater, Reduced Recharge,
                and Thin Aquifer for a 150 Meter Well.

 S7-150R1T2,  GW 10M,  D 150M,  R 0.25M/Y,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.4461E+01
7.0248E+00
l.OOOOE+04
5.8828E+02
3.0778E+01
2.5236E+03
5.6694E-01
1.6676E+02
1.6187E+03
l.OOOOE+04
2.4487E+02
7.0114E-02
l.OOOOE+04
1.0591E+03
3.4225E+01
6.2051E-01
% DIFFERENCE
-39.5 %
-25.6 %
0.0 %
15.8 %
30.7 %
-74.8 %
-33.3 %
-33.3 %
11503.6 %
0.0 %
1324.2 %
0.0 %
20228.9 %
-28.1 %
-33.4 %
-44.2 %
     This  case is similar  to  S7-150 RI  (Table  32)  with  a  thin  aquifer
and  S7-150T2  (Table  31)   with  reduced  recharge.   The  results  most
closely  resemble  that  latter  suggesting  that  the  thinning  of  the
aquifer  has more  impact  than the  reduced  recharge.  Observations  are
similar  to  those  made in  case S7-150T2 (Table 31)  in that Lindane shows
a  major change   over  the  base   case  because  the   extra  depth  to
groundwater allows for significant degradation.   For  lead  and mercury,
unsaturated   zone   considerations   still    override   saturated   zone
dispersion.   Copper is unaffected because  it  is already  at the maximum
allowed  concentration of  10,000  mg/kg.
                                  44

-------
                               Table 34.

     The  Effects of Increased Depth to Groundwater, Thick Aquifer,
              and Minimal Recharge  for a  150 Meter Well.

 S7-150R2T1,  GW  10M,  FOC = 10-4,  D 150M,  R 0.00635M/Y,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.4233E+03
l.OOOOE+04
6.9666E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.5838E+02
7.0125E-02
l.OOOOE+04
6.4131E+03
4.6861E+03
9.1240E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
22926.9 %
0.0 %
8097.4 %
3897.4 %
11596.1 %
0.0 %
4892.6 %
0.0 %
20228.9 %
335.4 %
9025.3 %
8110.9 %
     The minimal recharge  has  a significant impact  on  this  case.   The
greatly reduced  recharge  holds contaminant  flux  to a  very  small  rate
which allows for significant dilution  in  the aquifer.   Once again, the
contaminants not  affected  by   this  change  are  those  already at  the
maximum allowable level of 10,000 mg/kg  (copper and  nickel)  and  those
for which the  vapor  pathway drives the risk (chlordane and  DMN).   The
BEHP  and  Lindane  results  are  similar  to  the  case  where   only  the
unsaturated   zone  is  enlarged  (S7-150,  Table  27)  since the greater
travel  time  created  by  this situation  allows for  vapor loss  to become
significant  for BEHP and degradation to become significant for Lindane.
                                  45

-------
                               Table 35.

     The Effects of  Increased Depth to Groundwater, Thin Aquifer,
              and Minimal Recharge  for a  150 Meter Well.

 S7-150R2T2,  GW  10M,  FOC = 10-4, D 150M,  R 0.00635M/Y, AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
3.5272E+03
1.7325E+02
l.OOOOE+04
1.1861E+01
4.1690E+03
1.6187E+03
l.OOOOE+04
7.6921E+02
7.0114E-02
l.OOOOE+04
5.4842E+03
8.5562E+02
1.5513E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
594.6 %
635.6 %
0.0 %
1295.7 %
1566.5 %
11503.6 %
0.0 %
4374.0 %
0.0 %
20228.9 %
272.3 %
1566.2 %
1296.1 %
     This  case closely  resembles the previous  case,  S7-150R2T1  (Table
34),  with  a very  thin  aquifer is place of  the  thick  (78.6  meter)  one.
Most   contaminants   show  little   change  suggesting   that   vertical
dispersivity is not of much  significance  for  these  cases.   The minimal
recharge  appears  to   be   the  factor   of   greatest   consequence  in
determining  contaminant  loading.   Once  again,  copper and nickel  are
already  at the maximum  allowable concentration of  10,000 mg/kg  in the
base   case  and  vapor   considerations  remain  dominant  for   DMN  and
chlordane.   As a  consequence,  the  aquifer  property  changes have  no
effect on  base case results  for  these  four  contaminants,  BEHP is still
vapor controlled with  the  deep unsaturated zone  and,  therefore,  shows
the  same  change  as  for  S7-150  (Table   27)  where  only  the   depth  to
groundwater  was changed.
                                  46

-------
                               Table 36.

    The Effects of  Increased Depth  to  Groundwater  and  Soil  Organic
                     Content for a 150 Meter Well.

 S8-150,  GW 10M,  FOC 0.01,  D 150M, HEL 10-4
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5227E+01
1.7091E+01
l.OOOOE+04
1.4402E+03
6.5761E+01
l.OOOOE+04
8.5249E-01
4.1008E+02
1.6323E+03
l.OOOOE+04
8.6674E+02
7.0106E-02
l.OOOOE+04
1.4714E+03
5.1359E+01
1.5747E+00
% DIFFERENCE
47.3 %
81.0 %
0.0 %
183.6 %
179.2 %
0.0 %
0.3 %
63.9 %
11601.1 %
0.0 %
4941.2 %
0.0 %
20228.9 %
-0.1 %
0.0 %
41.7 %
     This  case is similar to S7-150 (Table 27) with higher soil organic
content.   The effects compared to the base case are almost identical in
both cases except  for Lindane,  DDT,  and Toxaphene.   One would expect
the major impacts  to  be  focused on chemicals  with  strong interactions
with soil  organic  matter (i.e., high  Koc)  and this is the  case.   The
relative  difference for  BEHP,  Chlordane, and DMN are  minimized by the
dominance  of  vapor considerations.    PCBs  do  not  reflect  the change
because pulse time is too long for dispersion effect to be significant.
TCE is not well  retarded and  shows no  real  response  to  the increased
organic matter.
                                  47

-------
                               Table 37.

The Effects of Increased Depth to Groundwater and Soil Organic Content,
                Reduced Recharge for a 150  meter Well.

 S8-150R1,  GW 10M, FOC 0.01, DIST 150M, R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5205E+01
1.7401E+01
l.OOOOE+04
1.4426E+03
6.5003E+01
l.OOOOE+04
1.6997E+00
7.8177E+02
1.6309E+03
l.OOOOE+04
8.7337E+02
7.0109E-02
l.OOOOE+04
2.4051E+03
1.0271E+02
2.5366E+00
% DIFFERENCE
47.2 %
84.3 %
0.0 %
184.1 %
176.0 %
0.0 %
100.0 %
212.5 %
11591.0 %
0.0 %
4979.8 %
0.0 %
20228.9 %
63.3 %
100.0 %
128.3 %
     This case  is  analogous  to S7-150RI  (Table  28)  with a higher soil
organic  fraction.    The  close  comparison  of results  illustrates  the
minor  affect  of  soil  organic  matter compared  to  that of  the deeper
unsaturated zone and reduced  recharge.   B(A)P,  DDT,  and Toxaphene show
effects due to  the longer unsaturated  zone  travel  times  which permit
greater  dispersion  effects.    This  impact  is  not  noted  for  other
contaminants because of  large pulse  (release) times  compared to travel
times.
                                  48

-------
                               Table  38.

The Effect of Increased Depth to Groundwater and Soil Organic Content,
                Minimal Recharge for a 150 Meter Well.

 S8-150R2,  GW  10M,  FOC  0.01,  DIST 150M,  R 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.3432E+02
l.OOOOE+04
3.5669E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.8072E+02
7.0125E-02
l.OOOOE+04
6.2055E+03
2.5680E+03
5.3572E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
2593.3 %
0.0 %
4097.1 %
3897.4 %
11596.1 %
0.0 %
5022.5 %
0.0 %
20228.9 %
321.3 %
4900.7 %
4721.1 %
     This  case is analogous  to  S7-150R2 (Table 29) with  a  higher soil
organic  content.   The  results  are  almost  identical,  suggesting  that
recharge  effects and  unsaturated  zone depth are much  more  significant
here  than  is  soil  organic content.   The greater unsaturated  zone travel
times produced by retardation from zone organic matter effects only DDT
and Toxaphene  by allowing for more attenuation  in transit.
                                  49

-------
                               Table 39.

The Effects of Increased Depth to Groundwater and Soil Organic Content,
                  Thick Aquifer for a 150 Meter Well.

 S8-150T1, GW 10M, FOC 0.01, DIST 150M, AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5816E+01
1.7494E+01
l.OOOOE+04
1.4557E+03
6.6544E+01
l.OOOOE+04
1.7631E+00
8.0115E+02
1.6298E+03
l.OOOOE+04
8.7317E+02
7.0109E-02
l.OOOOE+04
2.3724E+03
9.3717E+01
3.2712E+00
% DIFFERENCE
49.7 %
85.3 %
0.0 %
186.7 %
182.5 %
0.0 %
107.5 %
220.3 %
11583.2 %
0.0 %
4978.6 %
0.0 %
20228.9 %
61.1 %
82.5 %
194.4 %
     This case  is the  same  as S7-150T1  (Table  30)  with a higher soil
organic  content.    As   expected,  only  the  chemicals  which   interact
strongly with soil organic  matter are affected.   These  are B(A)P, DDT,
Lindane, and  Toxaphene.  Lindane  experiences more degradation because
of the  added  travel  time created  by  the slower transport velocity due
to  retardation.    The  B(A)P,  DDT,  and  Toxaphene  experience  more
dispersion because of  the  slower  travel  time in the unsaturated zone.
Contaminants  such  as PCBs  have  too  high a release  time for the added
travel  time to allow any significant dispersion  effects.
                                   50

-------
                               Table 40.

The Effects of Increased Depth to Groundwater and Soil Organic Matter,
                  Thin Aquifer for  a  150 Meter Well.

 S8-150T2,  GW  10M,  FOC 0.01,  DIST 150M,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.7096E+01
8.2636E+00
3.4089E+03
7.0874E+02
3.4037E+01
1.0772E+03
2.8347E-01
1.3672E+02
1.6187E+03
l.OOOOE+04
8.3988E+02
7.0114E-02
l.OOOOE+04
5.7529E+02
1.7044E+01
5.2568E-01
% DIFFERENCE
-28.5 %
-12.5 %
-65.9 %
39.6 %
44.5 %
-89.2 %
-66.6 %
-45.3 %
11503.6 %
0.0 %
4785.0 %
0.0 %
20228.9 %
-60.9 %
-66.8 %
-52.7 %
     This  case  resembles S7-150T2 (Table 31) with a higher soil  organic
content.    Once  again,  the  reduced aquifer  thickness  stops  vertical
dispersion to  the point of preventing much  of  the dilution that occurs
in the  base  case.    The  only  contaminants  greatly  affected  by  the
increased  travel  time due  to  retention  on  soil  organic  matter  are DDT
and  Lindane.     Other   chemicals  with  high  Koc  values  show  modest
increases  because  the  other  factors   are  dominant.    The  impact  to
Lindane  concentrations  reflect  the  slower  travel  time  which increases
the amount of  Lindane lost to degradation.   Effects  on DDT reflect the
short pulse  time compared  to  travel times  so  that  enhanced  dispersion
still  has  an impact  on  allowable levels.
                                  51

-------
                               Table 41.

The Effect of Increased Depth to Groundwater and Soil Organic Content,
      'Thick Aquifer and Reduced Recharge for a 150 Meter Well.

 S8-150R1T1,  GW  10M,  FOC 0.01,  DIST 150M,  R  0.25M/Y,  AQ  78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
4.1787E+01
1.7640E+01
l.OOOOE+04
1.5347E+03
7.0072E+01
l.OOOOE+04
3.5262E+00
1.5276E+03
1.6298E+03
l.OOOOE+04
8.7682E+02
7.0109E-02
l.OOOOE+04
3.4944E+03
1.8743E+02
4.9536E+00
% DIFFERENCE
74.7 %
86.8 %
0.0 %
202.2 %
197.5 %
0.0 %
314.9 %
510.6 %
11583.2 %
0.0 %
4999.9 %
0.0 %
20228.9 %
137.2 %
265.0 %
345.8 %
     This  case  parallels S7-150R1T1 (Table 32)  with higher soil  organic
content.    Results  are  virtually  identical  to  those  for the  previous
case with  the  exception of  three contaminants  with  high Koc  values:
B(A)P,  DDT,  and Toxaphene.    For these  three  chemicals,  the  higher
organic  fraction increases unsaturated  zone travel  times  thus  allowing
for more  dispersion.    For  the other  highly  retarded chemicals,  long
pulse times,  degradation  (Lindane),  and  vapor  considerations  override
the effects arising  from slower velocities in  the unsaturated  zone.
                                  52

-------
                               Table 42.

The Effects of Increased Depth to Groundwater and Soil Organic Content,
        Thin Aquifer and Reduced Recharge for a 150 Meter Well.

 S8-150R1T2, GW 10M, FOC 0.01, DIST 150M, R 0.25M/Y, AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.4461E+01
7.0248E+00
l.OOOOE+04
5.8828E+02
3.0778E+01
2.2231E+03
5.6694E-01
2.5959E+02
1.6187E+03
l.OOOOE+04
8.5861E+02
7.0114E-02
l.OOOOE+04
1.0591E+03
3.4225E+01
8.4514E-01
% DIFFERENCE
-39.5 %
-25.6 %
0.0 %
15.8 %
30.7 %
-77.8 %
33.3 %
3.8 %
11503.6 %
0.0 %
4894.0 %
0.0 %
20228.9 %
-28.1 %
-33.4 %
-23.9 %
     This case  is  parallel to  Case S7-150R1T2  (Table  33)  with higher
soil organic  content.   As  expected,  results  are  almost  identical  for
all  but  the  contaminants  with  strong  organic  interactions  (high  Koc
values).   Significant  increases in allowable  sludge concentrations are
observed  for  B(A)P,  DDT,  and  Toxaphene.   These  three  chemicals  have
short enough  pulse  times  to  benefit  from  added  dispersion resulting
from the  greater  retention  on  soil  organic  matter.    Other  retarded
organics  do  not  show  these  effects  because of  vapor considerations
(BEHP,  Chlordane,   and DMN),   maximum  effects  of  degradation having
already been  attained  (Lindane),  and  excessive  release  (pulse) times
(PCB).
                                   53

-------
                               Table 43.

The Effects of Increased Depth to Groundwater and Soil Organic Content,
       Thick Aquifer  and Minimal  Recharge  for  a  150  Meter Well.

 S8-150R2T1,  GW 10M, FOC 0.01, DIST 150M, R 0.00635M/Y, AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.2277E+03
l.OOOOE+04
6.9666E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.8068E+02
7.0125E-02
l.OOOOE+04
6.4131E+03
4.6861E+03
1.0466E+02
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
22096.4 %
0.0 %
8097.4 %
3897.4 %
11596.1 %
0.0 %
5022.3 %
0.0 %
20228.9 %
335.4 %
9025.3 %
9318.6 %
     This case is the  same  as S7-150R2T1 (Table 34) with a higher soil
organic content.  The  results are virtually identical  to those for the
prior case  with  the exception  of DDT and  Toxaphene.   In these cases,
the added travel  time  resulting  from  retention  on  the greater mass of
soil  organic  matter  leads  to  more  dispersion  because  of  the  short
release (pulse)  times  compared  to overall  travel  time.   For all  other
contaminants,  the deeper  unsaturated  zone and minimal  recharge are the
overriding factors.
                                   54

-------
                               Table 44.

The Effects of Increased Depth to Groundwater and Soil Organic Content,
        Thin Aquifer and Minimal Recharge for a 150 Meter Well.

 S8-150R2T2, GW 10M, FOC 0.01, DIST 150M, R 0.00635M/Y, AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
3.5272E+03
1.7325E+02
l.OOOOE+04
1.1861E+01
5.2772E+03
1.6187E+03
l.OOOOE+04
8.7971E+02
7.0114E-02
l.OOOOE+04
5.4842E+03
8.5562E+02
1.7790E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
594.6 %
635.6 %
0.0 %
1295.7 %
2009.5 %
11503.6 %
0.0 %
5016.7 %
0.0 %
20228.9 %
272.3 %
1566.2 %
1501.0 %
     This case is the  same  as  S7-150R2T2 (Table 35) with a higher soil
organic content.   The higher organic matter level increases travel time
for chemicals with  high Koc values due  to  retention.   Only three such
contaminants are  effected  in  this case:   B(A)P,  DDT,  and Toxaphene.
The other chemicals,  as in the previous  cases,  are dominated by other
factors  such  as  degradation,   long  release  (pulse)  times,  and vapor
considerations.
                                   55

-------
                               Table 45.

            The Effect of Intermediate Depth to Groundwater
                         for a 150 Meter Well.

 S9_150,  GW 5M, UNS FOC 10-4,  D 150M, HEL 10-4
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.1503E+01
1.2409E+01
l.OOOOE+04
9.6360E+02
4.6550E+01
l.OOOOE+04
8.4983E-01
2.5007E+02
1.6274E+03
l.OOOOE+04
2.0650E+02
7.0109E-02
3.1398E+02
1.4711E+03
5.1357E+01
1.1132E+00
% DIFFERENCE
31.7 %
31.4 %
0.0 %
89.8 %
97.6 %
0.0 %
0.0 %
0.0 %
11566.0 %
0.0 %
1101.1 %
0.0 %
538.3 %
-0.1 %
0.0 %
0.2 %
This  case   resembles   S7-150   (Table   27)  with  the  unsaturated  zone
increased only half as much (i.e., 5 meters in place of 10 meters).   As
would be expected, the effect  is  noted on  those  contaminants for which
added time  of travel  in the unsaturated zone allows for more dispersion
or degradation.   The  effect  is  less   than that  noted with  a  10 meter
depth,  but  not  as much  as a  factor  of 2.   The effect  on  Lindane  is
almost identical  because 5 meters  provides enough  time  for most of the
chemical  to  degrade.    Chemicals  with  large  release   (pulse)  times
compared to  travel   times do not  display   the  increased  allowable
concentrations  because  the   added dispersion  does  not  affect  peak
height.   Basically, the  conclusions are  the   same as  those  for S7-150
(Table 27),  the  effects are less pronounced.
                                  56

-------
                               Table 46.

       The Effect of  Intermediate Depth to Groundwater, Reduced
                    Recharge for a  150 Meter Well.

 S9-150R1,  GW 5M,  DIST 150M, R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5335E+01
1.6381E+01
l.OOOOE+04
1.3778E+03
6.5385E+01
l.OOOOE+04
1.6997E+00
5.0014E+02
1.6274E+03
l.OOOOE+04
3.2181E+02
7.0109E-02
2.2535E+03
2.4059E+03
1.0271E+02
1.8615E+00
% DIFFERENCE
47.7 %
73.5 %
0.0 %
171.3 %
177.6 %
0.0 %
100.0 %
99.9 %
11566.0 %
0.0 %
1771.8 %
0.0 %
4481.1 %
63.3 %
100.0 %
67.5 %
     The  case   is  the  same  as S7-150R1  (Table  28)  with  the  depth
increase at 5 meters  instead of 10.   The  results  are  almost identical
with the  exception  of  Lindane.    Since  Lindane   is  degradable,  the
shorter travel  time with 5 meters of unsaturated zone accommodates much
less degradation.   Therefore,  allowable sludge levels do  not  increase
nearly  as  much  here as they did in  S7-150R1 (Table  28).
                                  57

-------
                               Table 47.

         The Effect of Intermediate Depth to Groundwater with
                 Minimal  Recharge at a 150 Meter Well.

 S9-150R2,  GW 5M,  DIST 150M,  R 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.4942E+03
3.1785E+02
l.OOOOE+04
3.5669E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.0313E+02
7.0125E-02
l.OOOOE+04
6.2055E+03
2.5680E+03
4.6715E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1178.8 %
1249.6 %
0.0 %
4097.1 %
3897.4 %
11596.1 %
0.0 %
4571.3 %
0.0 %
20228.9 %
321.3 %
4900.7 %
4104.0 %
     This  case  is  the  same as  S7-150R2  (Table  29)  with a  smaller
increase in  the  depth of the unsaturated zone.  Most of the results are
identical   illustrating  the  predominance  of  the  recharge  over  the
unsaturated   travel  time  differences.    Lead,  mercury,  and  DDT  show
smaller changes  with the reduced  unsaturated  zone.   All  are attenuated
by retention  on  soil   sufficiently  that  the unsaturated  zone  delays
create  sufficient  dispersion effects  to  be  observed  over  and  above the
effect  of  low recharge.
                                  58

-------
                               Table 48.

    The  Effect of Intermediate Depth to Groundwater,  Thick Aquifer.

 S9-150T1,  GW 5M, DIST 150M,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.1536E+01
1.2466E+01
l.OOOOE+04
9.9019E+02
4.6553E+01
l.OOOOE+04
1.7631E+00
4.8882E+02
1.6298E+03
l.OOOOE+04
3.1618E+02
7.0109E-02
2.3392E+03
2.3724E+03
9.3717E+01
2.3108E+00
% DIFFERENCE
31.8 %
32.0 %
0.0 %
95.0 %
97.7 %
0.0 %
107.5 %
95.4 %
11583.2 %
0.0 %
1739.0 %
0.0 %
4655.3 %
61.1 %
82.5 %
108.0 %
     This case  is  analogous  to S7-150T1  (Table 30)  with  only half the
depth to the  unsaturated  zone.  Most  results  are  identical  except for
five retarded  chemicals:    arsenic, cadmium,  lead,  mercury,  and  DDT.
For  these,  the  unsaturated   zone  depth  is  an  overriding  factor  and
allowable increases  are  proportional  to  the  unsaturated  depth ratios,
i.e.,  the   5  meter  values   are  roughly  have the  10  meter  values.
Comparison  with  the identical  case with a thinner aquifer S9-150 (Table
45)  reveals  that  the  added   aquifer  thickness  affects   only  organic
constituents with  retarded velocities  which  provide  enough travel  time
for  added   depth  to  allow   for  concentration  changes   arising  from
vertical  dispersivity.    BEHP,  Chlordane,   and  DMN  are   not  affected
because   vapor   considerations  are   overriding   for   these   three
contaminants.
                                  59

-------
                               Table 49.

          The  Effect of Intermediate Depth to Groundwater and
                  Thin Aquifer for  a  150  Meter Well.

 S9-150T2,  GW  5M,  FOC = 10-4,  DIST 150M,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.5879E+01
7.1807E+00
2.8862E+03
6.0737E+02
2.9224E+01
1.0646E+03
2.8347E-01
8.3400E+01
1.6174E+03
l.OOOOE+04
8.1765E+01
7.0114E-02
1.0488E+02
5.7529E+02
1.7044E+01
3.7113E-01
% DIFFERENCE
-33.6 %
-23.9 %
-71.1 %
19.6 %
24.1 %
-89.4 %
-66.6 %
-66.7 %
11494.3 %
0.0 %
375.6 %
0.0 %
113.2 %
-60.9 %
-66.8 %
-66.6 %
     This  case  is  the same  as  S7-150T2 (Table 31) with  only  half the
depth of unsaturated zone.   The  results are  nearly the same as for the
previous case except for  DDT  and  Lindane where the smaller unsaturated
zone allows  for less dispersion and degradation, respectively.   For all
other contaminants,  the   thin  aquifer  reduces  vertical  dispersion and
impacts  concentrations to the  point  of  overriding  the unsaturated zone
travel  time  effects.  When compared to S9-150 (Table 45), the impact of
the  thin  aquifer   is  very  clear  with  all  allowable  concentrations
dropping significantly save those  for BEHP,  Chlordane,  and DMN.   These
three contaminants   have  risks  driven  by  vapor  considerations  and,
therefore, do not respond to changes in  the aquifer dimensions.
                                  60

-------
                               Table 50.

  The Effect of  Intermediate  Depth  to  Groundwater, Thick Aquifer and
                 Reduced  Recharge  for a 150 Meter Well.

 S9-150R1T1,  GW 5M, DIST 150M, R 0.25M/Y, AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.7921E+01
1.7916E+01
l.OOOOE+04
1.3902E+03
6.5950E+01
l.OOOOE+04
3.5262E+00
9.7764E+02
1.6298E+03
l.OOOOE+04
4.5164E+02
7.0109E-02
l.OOOOE+04
3.4944E+03
1.8743E+02
3.6333E+00
% DIFFERENCE
58.5 %
89.7 %
0.0 %
173.8 %
180.0 %
0.0 %
314.9 %
290.8 %
11583.2 %
0.0 %
2526.9 %
0.0 %
20228.9 %
137.2 %
265.0 %
227.0 %
     This case  is  similar to S7-150R1TS  (Table 32)  with  only half the
depth of  unsaturated zone.   The  results  are roughly  comparable  with
only DDT  having a  significantly lower  concentration  corresponding  to
the shallower unsaturated zone.   All  other chemicals show little or no
effect  from the commensurate  decrease in unsaturated zone travel time.
When  compared  to   Case  S9-150  (Table  46),  most  of   the  organic
constituents  (except  for those  driven by  vapor  considerations  [BEHP,
Chlordane, and  DMN])  have increased  allowable sludge concentrations  as
a result  of the greater depth for vertical  dispersion.   This suggests
that at   150  meters  distance,   the   15  m  aquifer   restricts  vertical
dispersion for  organics.   Effects  are  much  less  notable  for  metals
where concentrations are controlled by geochemistry.
                                   61

-------
                               Table 51.

       The Effect of Intermediate Depth to Groundwater, Reduced
           Recharge  and a Thin Aquifer for a  150 Meter Well.

 S9-150R1T2,  GW 5M,  DIST 150M, R 0.25M/Y,  AQ  5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.-9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.8292E+01
8.3260E+00
5.3496E+03
7.3004E+02
3.4365E+01
6.4859E+03
5.6694E-01
1.6658E+02
1.6243E+03
l.OOOOE+04
1.4185E+02
7.0114E-02
l.OOOOE+04
1.0591E+03
3.4225E+01
6.2009E-01
% DIFFERENCE
-23.5 %
11.8 %
-46.5 %
43.8 %
45.9 %
-35.1 %
-33.3 %
-33.4 %
11543.7 %
0.0 %
725.0 %
0.0 %
20228.9 %
-28.1 %
-33.4 %
-44.2 %
     This  case  is  similar to S9-150R1  (Table  46) with  only  one-third
the aquifer thickness.   Results  demonstrate that the  impact  is  on  all
contaminants except BEHP, Chlordane, and DMN where  risks  are  driven  by
vapor considerations.   With these exceptions,  it  would appear that  all
chemicals  are  vertical  dispersion  limited  in the  thin aquifer  and,
therefore,   cannot  be  diluted  in   transit  as  they would  in  thicker
aquifers.   The changes are of a  lower  magnitude than those  observed  in
S9-150T2  (Table 49) with greater recharge.   This  illustrates how  the
reduced rate mitigates some of the  effect of the thin aquifer.
                                  62

-------
                               Table 52.

      The  Effect of Intermediate Depth to Groundwater and Minimal
           Recharge in a Thick Aquifer for a 150 Meter Well.

 S9-150R2T1,  GW 5M, DIST 150M, R 0.00635M/Y, AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.7180E+03
l.OOOOE+04
6.9666E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.3665E+02
7.0125E-02
l.OOOOE+04
6.4131E+03
4.6861E+03
9.1326E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
24178.2 %
0.0 %
8097.4 %
3897.4 %
11596.1 %
0.0 %
4766.2 %
0.0 %
20228.9 %
335.4 %
9025.3 %
8118.7 %
     Results  are  almost  identical to  those for S7-150R2T1  (Table  34)
where conditions are the  same except  for the depth  to groundwater.   The
affects  of the minimal recharge clearly  overwhelm  any  effects  from  the
extra 5  meters  of unsaturated depth.   Comparison to S9-150R2 (Table  47)
shows increases  in  allowable  sludge   concentrations  for  only  four
contaminants:   Lead, Mercury, TCE, and Toxaphene.  These are apparently
the  only  contaminants  for  which  the  thinner aquifer  significantly
affects  vertical  dispersion  where the greater  dispersion  is  useful  in
reducing peak concentrations.   In all  other cases  pulse  times are  too
large or other  considerations too  dominant for the  aquifer thickness to
be significant.
                                  63

-------
                               Table 53.

     The Effects of Intermediate Depth to Groundwater and Minimal
           Recharge in a Thin Aquifer for a  150 Meter Well.

 S9-150R2T2,  GW 5M,  DIST  150M,  R 0.00635M/Y,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
1.7634E+03
8.7264E+01
l.OOOOE+04
1.1861E+01
4.1690E+03
1.6187E+03
l.OOOOE+04
6.8234E+02
7.0114E-02
l.OOOOE+04
5.4842E+03
8.5562E+02
1.5513E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
247.2 %
270.5 %
0.0 %
1295.7 %
1566.5 %
11503.6 %
0.0 %
3868.7 %
0.0 %
20228.9 %
272.3 %
1566.2 %
1296.1 %
     Comparison  to  Case  S7-150R2T2  with  twice  the  unsaturated  zone
depth shows that  only  Lead,  Mercury, and DDT  are affected.   All  other
contaminants are  virtually identical  because  of the overriding effects
of minimal  recharge.    These  three  slow-moving  chemicals  change  with
reduced unsaturated  zone depths  because  their  pulse  times (releases)
are  short  compared  to  travel  times.   When  compared  to  Case  S9-150R2
(Table 47), this  case  suggests that  most  slow-moving  contaminants are
hindered   by  the restricted  aquifer  thickness   because  they  cannot
disperse   as  far  as  they otherwise might.    These  effects  are  not
observed   when  vapor   considerations  (BEHP,   Chlordane,   and  DMN)  or
degradation (Lindane)  are overriding factors.
                                  64

-------
                               Table 54.

         The Effect of  Intermediate  Depth  to  Groundwater  with
                    Increased  Soil Organic Content

 S10-150,  GW 5M,  FOC 0.01, D 150M, HEL 10-4, R 0.5 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.1372E+01
1.2448E+01
l.OOOOE+04
9.8871E+02
4.6550E+01
l.OOOOE+04
8.5249E-01
2.8002E+02
1.6322E+03
l.OOOOE+04
8.5320E+02
7.0125E-02
l.OOOOE+04
1.4723E+03
5.1359E+01
1.1823E+00
% DIFFERENCE
31.2 %
31.8 %
0.0 %
94.7 %
97.6 %
0.0 %
0.3 %
11.9 %
11600.4 %
0.0 %
4862.5 %
0.0 %
20228.9 %
0.0 %
0.0 %
6.4 %
     This case is  similar  to S8-150 (Table 36)  but  with  only half the
unsaturated zone  depth.   As expected,  concentrations are  about  half
those for  all chemicals where  the unsaturated zone  travel  time  is
significant for dispersion.   Vapor driven  chemicals (BEHP,  Chlordane,
and DMN) are  unaffected as  is Lindane where  degradation  is  sufficient
at either travel  time to drive  allowable concentrations to the limits.
The  unsaturated   depth  change   is  also  inconsequential  for  those
contaminants  where release times  are large  compared  to travel  times so
the added dispersion  is not  noticeable.   This  case  is also  similar to
S9-150  (Table 45)  with  a  much  greater soil  organic  content.    As
expected,  the  results  are very similar  between the two cases  except for
B(A)P, DDT,  Lindane,  and Toxaphene which  are all highly attenuated and,
therefore,  greatly retarded by the presence of large fractions of soil
organic  matter.
                                  65

-------
                               Table 55.

  The  Effect  of Intermediate Depth to Groundwater with Increased Soil
       Organic Content and Reduced Recharge at a 150 Meter Well.

 S10-150R1, GW 5M,  FOC 0.01, DIST 150M,  R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN -
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
-KjOQQOE'04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.5015E+01
1.6381E+01
l.OOOOE+04
1.3778E+03
6.5385E+01
l.OOOOE+04
1.6997E+00
5.4960E+02
1.6274E+03
l.OOOOE+04
8.6594E+02
7.0109E-02
l.OOOOE+04
2.4059E+03
1.0271E+02
1.9391E+00
% DIFFERENCE
46.4 %
73.5 %
0.0 %
171.3 %
177.6 %
0.0 %
100.0 %
119.7 %
11566.0 %
0.0 %
4936.6 %
0.0 %
20228.9 %
63.3 %
100.0 %
74.5 %
     These results  compare  closely with those  for  S8-150R1  (Table 37)
where the  conditions were  the  same  except  for  a  deeper  unsaturated
zone.  Only B(A)P is  significantly effected by the longer travel  times
which allow for more  dispersion.   For the  other contaminants,  the high
organic  content  and  reduced  recharge provide the  greatest  effects  on
allowable  sludge concentrations.  When compared to case S9-150R1 (Table
46),  this  case provides marked increases in allowable sludge levels for
organic   constituents   not   driven   by  vapor  considerations  (BEHP,
Chlordane,  and DMN) or  degradation (Lindane).   These increases reflect
the longer travel  times creates by retention on soil organic matter.
                                  66

-------
                               Table 56.

  The Effect of Intermediate Depth  to Groundwater and  Increased Soil
      Organic Content with Minimal  Recharge at a 150 Meter Well.

 S10-150R2,  GW  5M,  FOC 0.01,  DIST 150M,  R 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.4834E+03
3.2128E+02
l.OOOOE+04
3.5669E+01
l.OOOOE+04
1.6321E+03
l.OOOOE+04
8.7687E+02
7.0125E-02
l.OOOOE+04
6.2055E+03
2.5680E+03
4.6745E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1176.7 %
1264.1 %
0.0 %
4097.1 %
3897.4 %
11599.6 %
0.0 %
5000.2 %
0.0 %
20228.9 %
321.3 %
4900.7 %
4106.7 %
     When compared  to the  same  conditions with twice  the  unsaturated
zone depth  in  Case  S7-150R2  (Table  29),  these   results  are  nearly
identical except  for  Lead  and  Mercury.    These  slower  moving  metals
achieve less dispersion  during  the  shortened  unsaturated travel  time.
Ttre results are  identical  for Case  S9-150R2  (Table  47)  which has less
soil organic content.   This  illustrates that  minimal  recharge effects
dominate other  considerations such as soil  organic  content.
                                  67

-------
                               Table 57.

    The Effect of Intermediate Depth to Aquifer and Increased Soil
      Organic Content with a Thick Aquifer for a 150 Meter Well.

 S10-150T1,  GW 5M,  FOC  0.01,  DIST 150M,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.1536E+01
1.2466E+01
l.OOOOE+04
9.6583E+02
4.6553E+01
l.OOOOE+04
1.7631E+00
5.4748E+02
1.6298E+03
l.OOOOE+04
8.6550E+02
7.0109E-02
l.OOOOE+04
2.3724E+03
9.3717E+01
2.4448E+00
% DIFFERENCE
31.8 %
32.0 %
0.0 %
90.2 %
97.7 %
0.0 %
107.5 %
118.9 %
11583.2 %
0.0 %
4934.0 %
0.0 %
20228.9 %
61.1 %
82.5 %
120.0 %
     This case is similar to Case S9-150T1 (Table 48) with greater soil
organic content.  The  results are comparable except  for  B(A)P and DDT
whose high Koc  values  cause greater retention  in  the unsaturated zone
allowing for more dispersion.
                                  68

-------
                               Table 58.

  The Effect of Intermediate Depth  to Groundwater and Increased Soil
      Organic  Content  with a Thin Aquifer for a 150 Meter Well.

 S10-150T2,  GW  5M,  FOC  0.01,  DIST 150M,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.5879E+01
7.1807E+00
2.8862E+03
6.1028E+02
2.9224E+01
1.0144E+03
2.8347E-01
9.3358E+01
1.6174E+03
l.OOOOE+04
8.0249E+02
7.0114E-02
l.OOOOE+04
5.7529E+02
1.7044E+01
3.9315E-01
% DIFFERENCE
-33.6 %
-23.9 %
-71.1 %
20.2 %
24.1 %
-89.9 %
-66.6 %
-62.7 %
11494.3 %
0.0 %
4567.5 %
0.0 %
20228.9 %
-60.9 %
-66.8 %
-64.6 %
     This  case  is  like S9-150T2  (Table  49)  with greater  soil  organic
content.   The results are virtually the same except for DDT and Lindane
where attenuation  is  significant.    In  the  first  case,  the  slower
resulting  travel time  allows  for more dispersion.   In  the second case
it allows  for more  degradation of Lindane.
                                  69

-------
                               Table 59.

   The  Effect  of  Intermediate Depth to Groundwater,  Increased Soil
      '  Organic Content at Reduced  Recharge in a Thick Aquifer
                         for  a 150 Meter Well.

 S10-150R1T1, GW  5M,  FOC 0.01, DIST 150M, R 0.25M/Y,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
4.0664E+01
1.7916E+01
l.OOOOE+04
1.3902E+03
6.5950E+01
l.OOOOE+04
3.5262E+00
1.0743E+03
1.6298E+03
l.OOOOE+04
8.7269E+02
7.0109E-02
l.OOOOE+04
3.4944E+03
1.8743E+02
3.7847E+00
% DIFFERENCE
70.0 %
89.7 %
0.0 %
173.8 %
180.0 %
0.0 %
314.9 %
329.4 %
11583.2 %
0.0 %
4975.8 %
0.0 %
20228.9 %
137.2 %
265.0 %
240.6 %
     This  case is  similar  to Case S9-150R1T1  (Table  50)  except  it has
higher soil  organic  content.    As  one  would  expect,  the  resulting
impacts  are  small  except  for  DDT  which  is  highly  attenuated  and
experiences  greater  dispersion  with   the  extended  unsaturated  zone
travel times.
                                  70

-------
                               Table  60.

  The Effect of Intermediate Depth to Groundwater and Increased Soil
        Organic Matter with Reduced Recharge in a Thin Aquifer
                         for a  150 Meter  Well.

 S10-150R1T2,  GW  5M,  FOC  0.01,  DIST 150M,  R 0.25M/Y,  AQ  5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.8500E+01
8.2215E+00
5.5573E+03
7.2977E+02
3.4423E+01
3.4534E+03
5.6694E-01
1.8324E+02
1.6187E+03
l.OOOOE+04
8.3735E+02
7.0114E-02
l.OOOOE+04
1.0591E+03
3.4225E+01
6.4613E-01
% DIFFERENCE
-22.7 %
-12.9 %
-44.4 %
43.7 %
46.2 %
-65.5 %
-33.3 %
-26.8 %
11503.6 %
0.0 %
4770.3 %
0.0 %
20228.9 %
-28.1 %
-33.4 %
-41.9 %
     This  case  is comparable  with S9-150R1T2  (Table  51) except  that
there  is  greater  soil  organic content.    As  one  would expect,  the
results are also  comparable except for  those for DDT  and  B(A)P which
are highly attenuated and undergo greater dispersion as a result of the
longer travel  times.
                                  71

-------
                               Table  61.

 The Effect of  Intermediate  Depth  and  Increased  Soil  Organic  Content
    with Minimal Recharge in a Thick Aquifer for a 150 Meter Well.

 S10-150R2T1,  GW 5M,  FOC  0.01,  DIST 150M,  R 0.00635M/Y,  AQ  78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.9411E+03
l.OOOOE+04
6.9666E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.8068E+02
7.0125E-02
l.OOOOE+04
6.4131E+03
4.6861E+03
9.2104E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
25125.5 %
0.0 %
8097.4 %
3897.4 %
11596.1 %
0.0 %
5022.3 %
0.0 %
20228.9 %
335.4 %
9025.3 %
8188.7 %
     This  case  is  comparable to  Case  S9-150R2T1  (Table 52)  only  this
case has  higher soil  organic content.  The results are almost identical
between  the  two cases  revealing that  the minimal  recharge  overrides
other factors.
                                  72

-------
                               Table -62.
  The Effect t>? Intermediate Depth to Eroundwater and Jncreased Soil
      Organic Content with  Minimal Recharge in a Thin Aquifer at
                           *  150 Meter
 S10-15DRZT2,  EW 5M, FOC 0.01, DIST 15DM, H D.DD535M/Y, AQ 5 J
 tHEMTCAL

ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
                HEAL™        ALLOWABLE SLUDGE
               STANDARD      CONCENTRATION  (Mfi/Kfi)
                (MG/JJ      BASELINE   SEAISJTJVJTY  % OlffERENCf
5.0000E-02
JLOOOQE-02
1.3000E+00
5.000OT-TJ2
              1.7500E+00
3.DOOOE-04
2.4800E-01
2.1000E-03
1.TOUDE-D2
J.OOOOE-04
-4.0000E-03
4.540UE-04
5.0000E-D3
                           2.3920E-t-01
                           l.OOOOE-t-04
                           5.07B2E-t-02
1.1
1.QQQQE+Q4
l.DQQQE+M
1.7634E+03
S.7264E+Q1
l.OOOOE-i-04
                           S.4985E-01

                           l!3950E+01
4.2B32E+03
1.6187E+03
                           1.7193E-I-01
                           7.t)lllE-02
                           4.9191E+01
                           5.1333I+D1
B.7B43E402
7.0114E-02
1.0000E-i-T)4
5_4S42f^3
J-.5562E4-JD2
1.5513E-HH
 41706.0 %
105810.9 %
    JLfl %
   247.2 %
   270.5 %
     0.0 %
  1295.7 %
  1512.2 %
 11503.6 %
     0.0 %
  5009.2 %
     0.0 %
 2022B/9 %
   272.3 %
  1566,2 %
  1796.1 %
     This case  is  comparable to  Case  S9-150R2T2 (Table 53) but  with  a
higher  soil   organic content.    The  results are  virtually  identical
except for UDT -whfcfr "fc** -sHfrixrTtmxly -nrgTi a-rcentfatitm properties  to
benefit from the higher organic content.   Even here the effect is small
because of the dominant influence of minimal  recharge.
                                   73

-------
                               Table 63.

              The  Effect of Minimal  Depth to Groundwater.

 Sll  150,  GW  1M, UNS FOC 10-4,  D 150M,  HEL 10-4
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
2.4017E+01
9.6310E+00
l.OOOOE+04
5.3134E+02
2.5758E+01
l.OOOOE+04
8.4983E-01
2.5007E+02
1.6080E+03
l.OOOOE+04
5.1259E+01
7.0109E-02
7.5017E+01
1.4711E+03
5.1357E+01
1.1132E+00
% DIFFERENCE
0.4 %
2.0 %
0.0 %
4.6 %
9.4 %
0.0 %
0.0 %
0.0 %
11426.9 %
0.0 %
198.1 %
0.0 %
52.5 %
-0.1 %
0.0 %
0.2 %
     This  case  differs  from the  base  case  only  in that  it  has  an
unsaturated  zone  albeit  s small one.   Significant  effects  occur only
for BEHP,  DDT,  and Lindane.  All are highly attenuated.  The BEHP is so
slow to move  that the risk  reverts to  the  vapor pathway.   The added
time of travel  for Lindane allows  for  degradation.   For DDT, the pulse
(release)  time  is  small  enough  that  the added  travel  time  allows  for
dispersion to  reduce groundwater concentrations.
                                   74

-------
                               Table 64.

        The Effect of Minimal Depth to Groundwater and Reduced
                     Recharge at a 150 Meter Well.

 S11-150R1,  GW  1M,  DIST  150M, R 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.6776E+01
1.6312E+01
l.OOOOE+04
6.2215E+02
3.0978E+01
l.OOOOE+04
1.7050E+00
5.0030E+02
1.6079E+03
l.OOOOE+04
9.1805E+01
7.0125E-02
2.0926E+02
2.4077E+03
1.0272E+02
1.8686E+00
% DIFFERENCE
53.7 %
72.8 %
0.0 %
22.5 %
31.5 %
0.0 %
100.6 %
100.0 %
11426.2 %
0.0 %
434.0 %
0.0 %
325.4 %
63.5 %
100.0 %
68.2 %
     When  compared to Case S9-150R1  (Table  46),  this  case  with an even
shallower  unsaturated zone,  most chemicals have similar results because
of  the  relative   unimportance   of   the   unsaturated  zone  in  overall
attenuation  mechanisms.   Those  that are  affected  (Lead, Mercury,  DDT,
and  Lindane)  are  all  slower  moving contaminants  with small  release
(pulse)  times compared to  travel  times.   For  these,  the  longer travel
times allow  more  dispersion  and degradation  which results  in  higher
allowable  sludge concentrations.
                                  75

-------
                               Table 65.

        The Effect of Minimal Depth to Groundwater and Minimal
                     Recharge at a 150 Meter Well.

 S11-150R2,  GW  1M,  DIST  150M, R 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
1.5021E+03
7.4890E+01
l.OOOOE+04
3.5669E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
6.0039E+02
7.0125E-02
l.OOOOE+04
6.2055E+03
2.5680E+03
4.6715E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
195.8 %
218.0 %
0.0 %
4097.1 %
3897.4 %
11596.1 %
0.0 %
3392.1 %
0.0 %
20228.9 %
321.3 %
4900.7 %
4104.0 %
     This  case is similar to  Case  S9-150R2  (Table  47)  with a shallower
unsaturated  zone.   The results  are  nearly  identical except  for  those
for Lead,  Mercury,  and DDT which  are all slow moving  enough  and have
short enough  release  times  to  benefit  from the extra  dispersion that
comes with  the  longer  unsaturated zone  travel  times.    For  all  other
contaminants,  the minimal  recharge effects dominates all others.
                                  76

-------
                               Table 66.

            The  Effect of Minimal  Depth to Groundwater in a
                  Thick Aquifer at  a  150  Meter Well.

 S11-150T1,  GW 1M,  DIST 150M,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3'OOOE+OO
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
2.4128E+01
9.6949E+00
l.OOOOE+04
5.3150E+02
2.5881E+01
l.OOOOE+04
1.7631E+00
4.8882E+02
1.6198E+03
l.OOOOE+04
8.9369E+01
7.0109E-02
5.5788E+02
2.3724E+03
9.3717E+01
2.3108E+00
% DIFFERENCE
0.9 %
2.7 %
0.0 %
4.7 %
9.9 %
0.0 %
107.5 %
95.4 %
11511.5 %
0.0 %
419.8 %
0.0 %
1034.1 %
61.1 %
82.5 %
108.0 %
     This case is like S9-1150T1  (Table  48)  with a thinner unsaturated
zone.   The results are closer  to  the base case for most metals because
the shortened  travel  time  leads  to  less  dispersion  effects.    The
attenuation  largely  arises  from  geochemistry.    The  organics on  the
other   hand   have   large   retardation   factors   and   so   gain   more
proportionately from the small  unsaturated zone.   Some also remain  the
same because  only  a little  retardation  is required  to  allow  vapor
considerations or degradation to become the overriding  factor.   Results
are similar  to those in  Case Sll-150  (Table  63)  for metals  but  have
much higher  allowable sludge  concentrations  for
velocities allow  for more  vertical  dispersion  in
This suggests that most  organics  are constrained
15 meter  aquifer  at  a 150 meter distance.
organics  whose slow
the thicker aquifer.
in dispersing by the
                                  77

-------
                               Table  67.

           The  Effect  of Minimal  Depth  to  Groundwater in  a
                   Thin Aquifer at a  150 Meter Well.

 S11-150T2, GW  1M,  DIST 150M,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.1112E+00
1.4585E+01
6.6166E+00
2.8312E+03
4.9851E+02
2.4117E+01
1.0807E+03
2.8347E-01
8.3400E+01
1.5611E+03
l.OOOOE+04
1.7782E+01
7.0114E-02
2.4971E+01
5.7529E+02
1.7044E+01
3.7113E-01
4.6715E+01
% DIFFERENCE
-39.0 %
-29.9 %
-71.7 %
-1.8 %
2.4 %
-89.2 %
-66.6 %
-66.7 %
11090.7 %
0.0 %
3.4 %
0.0 %
-49.2 %
-60.9 %
-66.8 %
-66.6 %
4104.0 %
     When compared to Case Sll  150  (Table  63)  this  case with a thinner
aquifer clearly  shows  the effects  of  constrained  vertical  dispersion.
Only BEHP,  Chlordane,  and DMN remain unaffected because their allowable
concentrations are driven by  vapor  considerations  which are unaffected
by aquifer  characteristics.
                                  78

-------
                               Table  68.

   The  Effect  of  Minimal  Depth to  Groundwater and  Reduced  Recharge
                in a  Thick Aquifer  at a  150  Meter Well.

 S11-150R1T1, GW 1M,  DIST  150M, R 0.25M/Y, AQ  78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.6940E+01
1.7491E+01
l.OOOOE+04
6.2480E+02
3.0829E+01
l.OOOOE+04
3.5262E+00
9.7664E+02
1.6256E+03
l.OOOOE+04
1.5446E+02
7.0109E-02
1.5748E+03
3.4944E+03
1.8743E+02
3.6391E+00
% DIFFERENCE
54.4 %
85.2 %
0.0 %
23.0 %
30.9 %
0.0 %
314.9 %
290.4 %
11553.0 %
0.0 %
798.4 %
0.0 %
3101.4 %
137.2 %
265.0 %
227.5 %
     The results  in  this case are  similar to those  in  Case  S11-150R1
(Table  64)   which  has  a  thinner  aquifer  except  for  the  organic
contaminants  which  are not driven  by vapor  considerations.    For  the
bulk of the  organics, the thicker aquifer allows  for more dispersion of
the contaminant leading to higher  allowable  sludge  concentrations.   It
appears that  for these  contaminants, the  15 meter  aquifer  thickness
constrains  vertical  dispersion over the 150 meter travel  distance.
                                  79

-------
                               Table 69.

   The  Effect  of  Minimal  Depth to Groundwater and  Reduced  Recharge
                in a Thin Aquifer at a 150 Meter Well.

 S11-150R1T2, GW  1M,  DIST  150M, R 0.25M/Y,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.6064E+01
7.1561E+00
4.1999E+03
5.3451E+02
2.6360E+01
5.1574E+03
5.6694E-01
1.6658E+02
1.5935E+03
l.OOOOE+04
3.2831E+01
7.0114E-02
1.5748E+03
1.0591E+03
3.4225E+01
6.2009E-01
% DIFFERENCE
-32.8 %
-24.2 %
-58.0 %
5.3 %
11.9 %
-48.4 %
-33.3 %
-33.4 %
11322.9 %
0.0 %
91.0 %
0.0 %
3101.4 %
-28.1 %
-33.4 %
-44.2 %
     This  case is  similar  to Case S11-150R1 (Table 64)  with  a  thinner
aquifer.      The   results    are   all   much   lower  allowable   sludge
concentrations with the exception of BEHP,  Chlordane,  and DMN  where the
risks are  driven by  vapor  considerations.   The  lower  allowable levels
are  a  direct reflection  of limitations  on  vertical   dispersion  which
greatly reduces  dilution between the source and the well.
                                  80

-------
                               Table 70.

    The  Effect  of Minimal  Depth to Groundwater and Minimal  Recharge
                in a Thick Aquifer at a 150 Meter Well.

 S11-150R2T1,  GW 1M, DIST  150M, R 0.00635M/Y,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.1286E+03
l.OOOOE+04
6.9666E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
7.0154E+02
7.0125E-02
l.OOOOE+04
6.4131E+03
4.6861E+03
9.1326E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
21675.6 %
0.0 %
8097.4 %
3897.4 %
11596.1 %
0.0 %
3980.4 %
0.0 %
20228.9 %
335.4 %
9025.3 %
8118.7 %
     This case is  similar  to Case S11-150R2  (Table 65)  with  a  thicker
aquifer.    The results  are  comparable  except for  some  of the  slower
moving chemicals  such  as  Lead, Mercury,  Benzene,  TCE,   and  Toxaphene
where the added aquifer depth  allows  for  more vertical dispersion  and,
therefore,  higher allowable  sludge concentrations.  For  the most part,
the  minimal  recharge  dominates the  effects  leaving  little  room  for
further increases from the greater aquifer thickness.
                                  81

-------
                               Table 71.

 S11-150R2T2,  GW 1M,  DIST 150M,  R 0.00635M/Y,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
4.3751E+02
2.1325E+01
l.OOOOE+04
1.1861E+01
4.1690E+03
1.6187E+03
l.OOOOE+04
3.6631E+02
7.0114E-02
l.OOOOE+04
5.4842E+03
8.5562E+02
1.5513E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
-13.8 %
-9.5 %
0.0 %
1295.7 %
1566.5 %
11503.6 %
0.0 %
2030.6 %
0.0 %
20228.9 %
272.3 %
1566.2 %
1296.1 %
     This  case  is  similar  to Case  S11-150R2  (Table  65)  but  has  a
thinner aquifer.   The effect  of  the reduced  area  for  vertical  mixing
and dispersion is most prominent  with  slow moving  metals  and organics.
Unchanged  are the  organics driven by  vapor  considerations,  the  metals
controlled by geochemistry and metals  with brief release  (pulse)  times
which are  strongly affected by the low recharge levels.
                                  82

-------
                               Table 72.

      The  Effect  of Minimal  Depth to Groundwater with High Soil
                 Organic Content  at  a 150 Meter Well.

 S12  150, GW  1M,  FOC 0.01,  D  150M, HEL 10-4
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
2.4212E+01
9.7000E+00
l.OOOOE+04
5.3200E+02
2.5858E+01
l.OOOOE+04
8.5249E-01
2.5015E+02
1.6320E+03
l.OOOOE+04
7.5758E+02
7.0125E-02
l.OOOOE+04
1.4723E+03
5.1359E+01
1.1174E+00
% DIFFERENCE
1.2 %
2.7 %
0.0 %
4.8 %
9.8 %
0.0 %
0.3 %
0.0 %
11598.9 %
0.0 %
4306.3 %
0.0 %
20228.9 %
0.0 %
0.0 %
0.6 %
     This case  is  comparable  to  Sll-150  (Table  63)  with  higher  soil
organic  content.    The results  are  very  similar  except  for DDT  and
Lindane.    In the  first  case,  the  added  attenuation  affords  greater
dispersion effects, while in the  second  the  delays  allow more time for
degradation.
                                  83

-------
                               Table  73.

   The Effect of Minimal Depth to Groundwater and High Soil Organic
          Content with Reduced Recharge at a 150 Meter Well.

 S12-150R1,  GW  1M,  FOC 0.01,  DIST 150M,  R  0.25  M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.7630E+01
1.6891E+01
l.OOOOE+04
6.2448E+02
3.0901E+01
l.OOOOE+04
1.6997E+00
5.0115E+02
1.6274E+03
l.OOOOE+04
8.1063E+02
7.0109E-02
l.OOOOE+04
2.4059E+03
1.0271E+02
1.8609E+00
% DIFFERENCE
57.3 %
78.9 %
0.0 %
23.0 %
31.2 %
0.0 %
100.0 %
100.3 %
11566.0 %
0.0 %
4614.9 %
0.0 %
20228.9 %
63.3 %
100.0 %
67.5 %
     This case is similar to Case S11-150R1 (Table 64) with higher soil
organic content.  The  results are virtually  identical  for all  but  DDT
and Lindane.   For other well attenuated chemicals, the unsaturated zone
is too small  for the organic  content  to  have a major impact.   For DDT,
the attenuation is  large enough to enhance dispersion while for Lindane
it allows significantly more degradation.
                                  84

-------
                               Table 74.

     The  Effect  of Minimal  Depth to Groundwater and Increased Soil
       Organic Matter with  Minimal  Recharge at a 150 Meter Well.

 S12-150R2,  GW 1M,  FOC 0.01,  DIST 150M,  R 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
1.5024E+03
7.4166E+01
l.OOOOE+04
3.5669E+01
l.OOOOE+04
1.6321E+03
l.OOOOE+04
8.7687E+02
7.0125E-02
l.OOOOE+04
6.2055E+03
2.5680E+03
4.6745E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
195.9 %
214.9 %
0.0 %
4097.1 %
3897.4 %
11599.6 %
0.0 %
5000.2 %
0.0 %
20228.9 %
321.3 %
4900.7 %
4106.7 %
     This case  is  the  same  as Case  S11-150R2 (Table 65)  with  higher
soil  organic  content.    Results  are  almost  identical  for  all but  DDT
which is retarded enough to  benefit  from greater  dispersion.   For most
other chemicals, the minimal  recharge is the overriding  determinant of
allowable sludge contaminant concentrations.
                                  85

-------
                               Table  75.

    The  Effect  of  Minimal  Depth  to Groundwater and  Increased  Soil
        Organic Matter in a Thick Aquifer at a 150 Meter Well.

 S12-150T1,  GW  1M,  FOC  0.01,  DIST 150M,  AQ  78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
2.5258E+01
9.8462E+00
l.OOOOE+04
5.3150E+02
2.5881E+01
l.OOOOE+04
1.7631E+00
4.8882E+02
1.6298E+03
l.OOOOE+04
8.0881E+02
7.0109E-02
l.OOOOE+04
2.3724E+03
9.3717E+01
2.3108E+00
% DIFFERENCE
5.6 %
4.3 %
0.0 %
4.7 %
9.9 %
0.0 %
107.5 %
95.4 %
11583.2 %
0.0 %
4604.3 %
0.0 %
20228.9 %
61.1 %
82.5 %
108.0 %
     This  case  is  similar to  Case S12-150  (Table  72)  with a  thicker
aquifer  for more  vertical dispersion.   The  added  depth for  dilution
results  in  larger  allowable  sludge concentrations  for most  organics
arsenic  and cadmium.    The greatest  increases are  with the  organics
other than  those controlled by vapor considerations.
                                  86

-------
                               Table  76.

       The Effect of Minimal Depth to Groundwater and Increased
      Soil Organic Matter in a Thin Aquifer at a 150 Meter Well.

 S12-150T2,  GW  1M,  FOC  0.01,  DIST  150M,  AQ  5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.4585E+01
6.6166E+00
2.8184E+03
4.9851E+02
2.4117E+01
1.0108E+03
2.8347E-01
8.3400E+01
1.6314E+03
l.OOOOE+04
5.9104E+02
7.0114E-02
l.OOOOE+04
5.7529E+02
1.7044E+01
3.7113E-01
% DIFFERENCE
-39.0 %
-29.9 %
-71.8 %
-1.8 %
2.4 %
-89.9 %
-66.6 %
-66.7 %
11594.6 %
0.0 %
3337.7 %
0.0 %
20228.9 %
-60.9 %
-66.8 %
-66.6 %
     This  case  is  similar  to  Case S12-150  (Table  72)  with  a  thinner
aquifer.     The   latter   condition  restricts  vertical  dispersion  and
results  in  much  lower allowable sludge concentrations for all  chemicals
except  those that are driven by  vapor considerations (BEHP,  Chlordane,
and DMN)  and Lindane where degradation overrides other factors.
                                  87

-------
                               Table 77.

      The Effect of Minimal Depth to Groundwater,  Increased Soil
        Organic Matter and Reduced  Recharge in a Thick Aquifer
                         at a  150 Meter Well.

 S12-150R1T1,  GW 1M,  FOC  0.01,  DIST 150M,  R 0.25M/Y,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
3.8315E+01
1.6888E+01
l.OOOOE+04
6.2480E+02
3.0829E+01
l.OOOOE+04
3.5262E+00
9.7664E+02
1.6298E+03
l.OOOOE+04
8.4103E+02
7.0109E-02
l.OOOOE+04
3.4944E+03
1.8743E+02
3.6391E+00
% DIFFERENCE
60.2 %
78.9 %
0.0 %
23.0 %
30.9 %
0.0 %
314.9 %
290.4 %
11583.2 %
0.0 %
4791.7 %
0.0 %
20228.9 %
137.2 %
265.0 %
227.5 %
     This case is similar to Case S11-150R1T1 (Table 68) but has higher
soil  organic  content.    The net effect  is  limited to  DDT  and  Lindane
where retention in the unsaturated  zone  allows  for more dispersion and
degradation,  respectively.  The effects for the greater retardation are
limited because of the extremely thin unsaturated zone.
                                  88

-------
                               Table 78.

  The Effect of Minimal Depth to Groundwater, Increased Soil Organic
  Content  and  Reduced Recharge in a Thin  Aquifer at a 150  Meter Well.

 S12-150R1T2,  GW 1M,  FOC 0.01, DIST 150M, R 0.25M/Y,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
1.00aOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
1.6064E+01
7.1561E+00
4.2274E+03
5.3451E+02
2.6360E+01
4.5990E+03
5.6694E-01
1.6658E+02
1.6187E+03
l.OOOOE+04
6.9875E+02
7.0114E-02
l.OOOOE+04
1.0591E+03
3.4225E+01
6.2009E-01
% DIFFERENCE
-32.8 %
-24.2 %
-57.7 %
5.3 %
11.9 %
-54.0 %
-33.3 %
-33.4 %
11503.6 %
0.0 %
3964.2 %
0.0 %
20228.9 %
-28.1 %
-33.4 %
-44.2 %
     This case is the same as Case S11-150R1T2 (Table 69) with a higher
soil  organic content.   The results are virtually  identical  except  for
DDT  and  Lindane.    These   two   chemicals   are   still   sensitive   to
unsaturated  zone movement  and,  as  such,  have   more  dispersion  and
degradation,  respectively.  The effects are limited because of the very
thin  unsaturated zone over which they can occur.
                                  89

-------
                               Table 79.

  TKe Effect of Minimal Depth to Groundwater, Increased Soil Organic
 Content and Minimal Recharge in a Thick Aquifer at a 150 Meter Well,

 S12-150R2T1,  GW  1M,  FOC 0.01,  DIST 150M,  R 0.00635M/Y,  AQ 78.6M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.8285E+03
l.OOOOE+04
6.9666E+01
l.OOOOE+04
1.6316E+03
l.OOOOE+04
8.7882E+02
7.0125E-02
l.OOOOE+04
6.4131E+03
4.6861E+03
9.1326E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
1869.2 %
24647.4 %
0.0 %
8097.4 %
3897.4 %
11596.1 %
0.0 %
5011.5 %
0.0 %
20228.9 %
335.4 %
9025.3 %
8118.7 %
     This  is  the same case as Case S11-150R2T1 (Table 70) only there is
more soil  organic  content.    Results  are nearly  identical  between  the
two because  the minimal recharge  dominates  the  affects  by slowing time
of travel  significantly.
                                  90

-------
                               Table  80.

  The Effect of Minimal Depth to Groundwater and Recharge, Increased
      Soil  Organic Matter in a Thin Aquifer at a 150 Meter Well.

 S12-150R2T2,  GW  1M,  FOC  0.01,  DIST 150M,  R 0.00635M/Y,  AQ 5.0M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3920E+01
9.4419E+00
l.OOOOE+04
5.0782E+02
2.3552E+01
l.OOOOE+04
8.4985E-01
2.5016E+02
1.3950E+01
l.OOOOE+04
1.7193E+01
7.0111E-02
4.9191E+01
1.4729E+03
5.1353E+01
1.1112E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
4.3751E+02
2.1325E+01
l.OOOOE+04
1.1861E+01
4.1690E+03
1.6187E+03
l.OOOOE+04
8.6838E+02
7.0114E-02
l.OOOOE+04
5.4842E+03
8.5562E+02
1.5513E+01
% DIFFERENCE
41706.0 %
105810.9 %
0.0 %
-13.8 %
-9.5 %
0.0 %
1295.7 %
1566.5 %
11503.6 %
0.0 %
4950.8 %
0.0 %
20228.9 %
272.3 %
1566.2 %
1296.1 %
     This  case is  the  same as Case S11-150R2T2  (Table  71)  with  higher
soil  organic content.  The results  are  identical  with  the exception of
DDT  where  the  higher  organic  levels  retard  unsaturated  movement
allowing  for more  dispersion.  Hence,  allowable  sludge concentrations
are greater for DDT with the  larger soil organic content.
                                  91

-------
         Table 81.
Base Case for 50 Meter Well.
B-50
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
t
4
9
1
4
4
1
5
2
2
3
1
4
4
2
4
5
AQUIFER
.960E-02
.OOOE-03
.260E+00
.900E-02
.570E-04
.390E+00
.OOOE-03
.990E-04
.420E-01
.020E-04
.OOOE-02
.740E-28
.480E-03
.490E-04
.980E-03
.OOOE-03

0
0
0
0
0
0
0
2
5
4
1
1
0
2
0
0
VAPOR
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.854E-11
.292E-03
.388E-04
.809E-04
.OOOE-04
.OOOE+00
.049E-04
.OOOE+00
.OOOE+00
1
4
1
1
1
3
2
0
0
0
0
0
0
0
0
0
0
BACKGRND
.OOOE-04
.OOOE-03
.OOOE-02
.OOOE-03
.OOOE-04
.700E-03
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00

5
1
1
5
7
1
5
2
2
7
1
1
4
4
4
5
SUM
.OOOE-02
.OOOE-02
.270E+00
.OOOE-02
.570E-04
.393E+00
.OOOE-03
.990E-04
.473E-01
.408E-04
.018E-02
.OOOE-04
.480E-03
.539E-04
.980E-03
.OOOE-03

5
1
1
5
2
1
5
3
2
2
1
1
4
4
5
5
HEL
.OOOE-02
.OOOE-02
.300E+00
.OOOE-02
.OOOE-03
.750E+00
.OOOE-03
.OOOE-04
.480E-01
.100E-03
.020E-02
.OOOE-04
.OOOE-03
.540E-04
.OOOE-03
.OOOE-03
DRY WGHT
6.140E+00
2.747E+00
l.OOOE+04
2.394E+02
l.OOOE+04
l.OOOE+04
6.438E-01
2.259E+02
1.091E+01
l.OOOE+04
4.892E+00
2.196E-02
1.276E+01
9.387E+02
2.116E+01
8.416E-01
             92

-------
                               Table 82.

     Effects of Increasing Depth to Groundwater from 0 to 10 Meters
                           at  a  50  Meter Well.

 S7-50,  GW 10M, FOC 0.0001, D 50M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
1.1660E+01
4.7769E+00
l.OOOOE+04
4.7031E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
5.1099E+02
l.OOOOE+04
1.2365E+02
2.1959E-02
3.9042E+02
9.3867E+02
2.1159E+01
8.4160E-01
% DIFFERENCE
89.9 %
73.9 %
0.0 %
96.5 %
0.0 %
0.0 %
0.0 %
0.0 %
4583.3 %
0.0 %
2427.5 %
0.0 %
2632.9 %
0.0 %
0.0 %
0.0 %
     This case is  similar  to case S7-150  (Table  27)  with  the exposure
point closer to  the  source (50 meters as  opposed  to  150 meters).   The
allowable sludge  concentrations  are generally less than those  for the
150 meter case because there  is  less  travel  time over which dispersion
will  occur.   These effects  are  noted mostly  for  chemicals  with short
release  (pulse)  times compared  to  travel  times.   They are  not noted
where vapor considerations or unsaturated zone effects control risk.
     In  two  cases,  arsenic  and  DDT,  the  allowable  concentrations are
greater compared  to the base case because of the relative importance of
unsaturated  transport versus  saturated  transport.    Copper,  mercury,
nickel,  and  chlordane  were  already  at the  maximum  allowable  sludge
concentrations of 10,000 mg/kg in the base case.
                                  93

-------
                               Table 83.

         Effects of  Increased Depth to Groundwater  (10 Meters)
        and Increased Soil Organic  Content at a 50  Meter Well.

 S8-50,  GW  10M,  FOC 0.01,  D 50M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
1.1603E+01
4.7770E+00
l.OOOOE+04
4.7053E+02
l.OOOOE+04
l.OOOOE+04
6.4448E-01
3.7044E+02
5.1125E+02
l.OOOOE+04
2.7256E+02
2.1958E-02
l.OOOOE+04
9.3897E+02
2.1160E+01
1.1873E+00
% DIFFERENCE
89.0 %
73.9 %
0.0 %
96.5 %
0.0 %
0.0 %
0.1 %
64.0 %
4585.6 %
0.0 %
5471.3 %
0.0 %
69898.6 %
0.0 %
0.0 %
41.1 %
     This  case  is the  same  as  S7-50  (Table  82)  with  a higher  soil
organic content.   The higher  organic  levels  effect  retention  of highly
retarded contaminants and,  therefore,  this setting  has higher  allowable
sludge levels for B(A)P, DDT, and Toxaphene due to  greater dispersion
and  Lindane  due  to  greater degradation.    Other   chemicals  are  not
effected because  they have  long  release times which  do not benefit from
the  longitudinal  dispersion provided  by   delayed   transport  in  the
unsaturated  zone.   Copper,   mercury, nickel,  and  chlordane were already
at the maximum allowable sludge  level  of 10,000 mg/kg.
                                  94

-------
                               Table 84.

     Effects of Increasing Depth to Groundwater from 0 to 5 Meters
                          at  a 50 Meter Well.

 S9-50,  GW 5M,  FOC 0.0001,  D  50M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
8.4328E+00
3.2177E+00
l.OOOOE+04
3.4583E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
5.1073E+02
l.OOOOE+04
7.9469E+01
2.1959E-02
9.1326E+01
9.3867E+02
2.1159E+01
8.4160E-01
37.4 %
17.1 %
0.0 %
44.5 %
0.0 %
0.0 %
0.0 %
0.0 %
4580.9 %
0.0 %
1524.4 %
0.0 %
539.3 %
0.0 %
0.0 %
0.0 %
     This case  is  similar  to  S7-50 (Table 82)  but  has only  half  the
depth to  groundwater.    As  expected,  the reduced  travel  time  in  the
unsaturated  zone reduces the dispersion and degradation effects leading
to lower allowable sludge  levels for chemicals where  the  release  time
is short compared to the travel  time.   These  include arsenic,  cadmium,
lead, DDT,  and  Lindane.    BEHP,  chlordane,   and DMN are  unaffected
because  their  risk  levels are driven by vapor  considerations.
                                  95

-------
                               Table 85.

     Effects of Increased Depth to  Groundwater  from 0 to  5 Meters
        and Increased Soil Organic  Content  at a 50 Meter  Well.

 S10-50,  GW 5M,  FOC 0.01, D 50M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
8.4437E+00
3.2488E+00
l.OOOOE+04
3.4600E+02
l.OOOOE+04
l.OOOOE+04
6.4448E-01
2.5295E+02
5.1126E+02
l.OOOOE+04
2.6935E+02
2.1964E-02
l.OOOOE+04
9.3955E+02
2.1160E+01
8.9385E-01
% DIFFERENCE
37.5 %
18.3 %
0.0 %
44.5 %
0.0 %
0.0 %
0.1 %
12.0 %
4585.7 %
0.0 %
5405.7 %
0.0 %
69898.6 %
0.1 %
0.0 %
6.2 %
     This case  is  the  same  as  S9-50  (Table  84)  with  a  higher  soil
organic  content.     As   a   result,   the  allowable  sludge  levels  are
comparable except  for  those  for  B(A)P,  DDT,  Lindane,  and Toxaphene.
These  four  chemicals sorb  strongly  to organic matter  and, therefore,
move more slowly  whe a  there  is more  soil  organic  matter.   Since they
have small release  times compared  to travel  times,  the outcome is more
dispersion  which   reduces  groundwater  concentrations.   Other  highly
retarded  organics  are  not  affected  because they are driven  by  vapor
considerations  (BEHP,  Chlordane,  and  DMN)  or  because they  have  long
release times (PCB).
                                   96

-------
                               Table 86.

      Effects of Increased Depth to Groundwater from 0 to 1  Meter
                          at a 50 Meter Well.

 Sll-50,  GW 1M,  FOC 0.0001,  D 50M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2J959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.1889E+00
2.7644E+00
l.OOOOE+04
2.3547E+02
l.OOOOE+04
l.OOOOE+04
6.4448E-01
2.2597E+02
5.0862E+02
l.OOOOE+04
2.0857E+01
2.1964E-02
2.1803E+01
9.3955E+02
2.1160E+01
8.4645E-01
% DIFFERENCE
0.8 %
0.6 %
0.0 %
-1.6 %
0.0 %
0.0 %
0.1 %
0.0 %
4561.5 %
0.0 %
326.3 %
0.0 %
52.6 %
0.1 %
0.0 %
0.6 %
     This  case  is  like  S9-50   (Table   84)   with   an   even   smaller
unsaturated zone.  Conversely,  it  is  like  the  base case  with a minimal
unsaturated zone.  The  1  meter of unsaturated  soil  sufficiently  slows
down a few organics to affect allowable sludge concentrations.   Namely,
BEHP  is  held  up  to the  point  that vapor  transport dominates  risk
considerations.  DDT is slowed  such  that dispersion  affects  reduce its
peak groundwater  concentrations  and  Lindane  is  held long  enough  for
degradation to  become  significant.   The  other chemicals either  move
more rapidly or have  too long a release time to benefit.
                                  97

-------
                               Table 87.

     Effects of Increasing Depth to Groundwater from 0 to 1 Meter
        and  Increasing Soil  Organic Content from 0.0001  to 0.01
                          at a 50 Meter Well.

 S12-50,  GW  1M,  FOC 0.0001,  D BOM
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.1889E+00
2.7645E+00
l.OOOOE+04
2.3547E+02
l.OOOOE+04
l.OOOOE+04
6.4448E-01
2.2597E+02
5.1126E+02
l.OOOOE+04
2.4563E+02
2.1964E-02
l.OOOOE+04
9.3955E+02
2.1160E+01
8.4645E-01
% DIFFERENCE
0.8 %
0.6 %
0.0 %
-1.6 %
0.0 %
0.0 %
0.1 %
0.0 %
4585.7 %
0.0 %
4920.8 %
0.0 %
69898.6 %
0.1 %
0.0 %
0.6 %
     This  case  is the  same  as  Sll-50  (Table  86) except  for a  much
higher soil  organic  content.   The net  results  are the same  only  the
effects  are more pronounced so that allowable sludge concentrations  are
even higher.
                                  98

-------
            Table  88.
Base Case for Well at 500 Meters.
B-500
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
i
4
8
3
1
3
8
4
3
2
1
9
0
4
4
5
5
AQUIFER
.950E-02
.960E-03
.870E-01
.030E-01
.460E-04
.540E-01
.990E-03
.OOOE-04
.470E-01
.650E-20
.730E-03
.OOOE+00
.OOOE-03
.280E-04
.OOOE-03
.OOOE-03

0.
0.
0.
0.
0.
0.
0.
2.
4.
2.
4.
1.
0.
2.
0.
0.
VAPOR
OOOE+00
OOOE+00
OOOE+00
OOOE+00
OOOE+00
OOOE+00
OOOE+00
083E-12
719E-04
420E-05
702E-04
OOOE-04
OOOE+00
565E-05
OOOE+00
OOOE+00

4
1
1
1
3
2
0
0
0
0
0
0
0
0
0
0
BACKGRND
.OOOE-04
.OOOE-03
.OOOE-02
.OOOE-03
.OOOE-04
.700E-03
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00

4
9
3
1
6
8
4
3
2
2
1
1
4
4
5
5
SUM
.990E-02
.960E-03
.970E-01
.040E-01
.460E-04
.567E-01
.990E-03
.OOOE-04
.475E-01
.420E-05
.020E-02
.OOOE-04
.OOOE-03
.536E-04
.OOOE-03
.OOOE-03

5
1
1
5
2
1
5
3
2
2
1
1
4
4
5
5
HEL
.OOOE-02
.OOOE-02
.300E+00
.OOOE-02
.OOOE-03
.750E+00
.OOOE-03
.OOOE-04
.480E-01
.100E-03
.020E-02
.OOOE-04
.OOOE-03
.540E-04
.OOOE-03
.OOOE-03
DRY WGHT
1.058E+02
4.669E+01
l.OOOE+04
2.481E+03
l.OOOE+04
l.OOOE+04
1.159E+00
2.989E+02
1.764E+01
l.OOOE+04
2.306E+02
3.982E-01
1.173E+03
2.130E+03
1.304E+03
1.518E+00
               99

-------
                               Table 89.

     Effects of Increasing Depth to Groundwater from 0 to 10 Meters
                          at  a  500  Meter Well.

 S7-500,  GW 10M,  FOC 0.0001,  DIST 500M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
SENSITIVITY
CONC
(MG/L)
5.00E-02
l.OOE-02
3.87E-01
1.03E-01
3.46E-04
8.54E-01
4.99E-03
3.00E-04
2.47E-01
1.65E-20
9.73E-03
O.OOE+00
4.00E-03
4.28E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.06E+02
4.67E+01
l.OOE+04
2.48E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
1.76E+01
l.OOE+04
2.31E+02
3.98E-01
1.17E+03
2.13E+03
1.30E+03
1.52E+00
1.07E+02
4.76E+01
l.OOE+04
3.65E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
9.20E+03
l.OOE+04
3.67E+03
3.98E-01
l.OOE+04
2.13E+03
1.30E+03
1.52E+00
% DIFFERENCE
1.0 %
1.9 %
0.0 %
47.2 %
0.0 %
0.0 %
0.0 %
0.0 %
52059.9 %
0.0 %
1490.6 %
0.0 %
752.5 %
0.0 %
0.0 %
0.0 %
     This case  demonstrates  that as the  monitoring  point  gets further
from the  source,  changes  in  the  unsaturated  zone  depth  become  less
significant  for  most  chemicals.    Only  lead,  BEHP,  DDT,  and Lindane
benefit significantly  from the added  unsaturated  zone  transport time.
These  are  some  of  the  more  retarded contaminants with  sufficiently
short release periods that they benefit from added dispersion.  Lindane
also benefits from any delay because of the added degradation.  Copper,
mercury,  nickel,  and chlordane were  already at the maximum allowable
sludge  concentration of 10,000 mg/kg in the base case.
                                  100

-------
                               Table 90.

    Effects of Increasing Depth to  Groundwater from 0 to 10 Meters
        and  Increasing Soil  Organic Content from  0.0001  to  0.01
                         at a 500 Meter Well.

 S8-500,  GW=10M,  FOC=0.01,  DIST=500M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
SENSITIVITY
CONC
(MG/L)
5.00E-02
l.OOE-02
3.87E-01
1.03E-01
3.46E-04
8.54E-01
4.99E-03
3.00E-04
2.47E-01
1.65E-20
9.73E-03
O.OOE+00
4.00E-03
4.28E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.06E+02
4.67E+01
l.OOE+04
2.48E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
1.76E+01
l.OOE+04
2.31E+02
3.98E-01
1.17E+03
2.13E+03
1.30E+03
1.52E+00
1.07E+02
4.75E+01
l.OOE+04
3.65E+03
l.OOE+04
l.OOE+04
1.16E+00
4.90E+02
9.27E+03
l.OOE+04
4.99E+03
3.98E-01
l.OOE+04
2.13E+03
1.30E+03
2.15E+00
% DIFFERENCE
1.0 %
1.8 %
0.0 %
47.1 %
0.0 %
0.0 %
0.5 %
64.0 %
52445.4 %
0.0 %
2061.8 %
0.0 %
752.5 %
0.0 %
0.0 %
41.7 %
     This case  is the  same as  S7-500  (Table 89)  with a  much  higher
level  of  organic  matter  in the soil.   As expected, the  major  impact
occurs  with  the  organics where   the  higher   retardation  enhances
dispersion effects.   Among  the  organics,  only chlordane and DMN  remain
unaffected.   This  results from chlordane's already  having reached the
maximum  level   of  10,000  mg/kg  and  DMN's  being  driven  by   vapor
considerations.
                                  101

-------
                               Table  91.

     Effects  of Increasing  Depth  to  Groundwater  from  0  to  5 Meters
                         at a 500 Meter Well.

 S9-500,  GW=5M,  FOC=0.0001,  DIST=500M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
SENSITIVITY
CONC
(MG/L)
5.00E-02
l.OOE-02
3.87E-01
1.03E-01
3.46E-04
8.54E-01
4.99E-03
3.00E-04
2.47E-01
1.65E-20
9.73E-03
O.OOE+00
4.00E-03
4.28E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.06E+02
4.67E+01
l.OOE+04
2.48E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
1.76E+01
l.OOE+04
2.31E+02
3.-98E-01
1.17E+03
2.13E+03
1.30E+03
1.52E+00
1.07E+02
4.70E+01
l.OOE+04
3.11E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
9.14E+03
l.OOE+04
2.89E+03
3.98E-01
7.51E+03
2.13E+03
1.30E+03
1.52E+00
% DIFFERENCE
1.0 %
0.7 %
0.0 %
25.5 %
0.0 %
0.0 %
0.0 %
0.0 %
51697.1 %
0.0 %
1155.0 %
0.0 %
540.4 %
0.0 %
0.0 %
0.0 %
     This case is the same as S7-500 (Table 89)  but with  half the  depth
to ground water.   The effects  are  the same but less  pronounced  since
the shallower depth  to groundwater  leads to less  time for  degradation
(Lindane) and less dispersion in the unsaturated zone.
                                  102

-------
                               Table 92.

     Effects  of Increasing Depth to Groundwater from 0 to 5 Meters
        and  Increasing Soil  Organic Content from 0.0001 to 0.01
                          at a  500  Meter Well.

 S10-500,  GW=5M,  FOC=0.01, DIST=500M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
l.OOE-03
3.87E-01
1.03E-01
3.46E-04
8.54E-01
4.99E-03
3.00E-04
2.47E-01
1.65E-20
9.73E-03
O.OOE+00
4.00E-03
4.28E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.06E+02
4.67E+01
l.OOE+04
2.48E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
1.76E+01
l.OOE+04
2.31E+02
3.98E-01
1.17E+03
2.13E-t-03
1.30E+03
1.52E+00
1.07E+02
4.70E+01
l.OOE+04
3.11E+03
l.OOE+04
l.OOE+04
1.16E+00
3.35E+02
9.27E+03
l.OOE+04
4.97E+03
3.98E-01
l.OOE+04
2.13E+03
1.30E+03
1.61E+00
% DIFFERENCE
1.0 %
0.8 %
0.0 %
25.4 %
0.0 %
0.0 %
0.3 %
12.0 %
52439.7 %
0.0 %
2053.9 %
0.0 %
752.5 %
0.0 %
0.0 %
5.9 %
     This case is the same as S8-500 (Table 90) but with half the depth
to ground water.   As expected,  the effect is seen  on  chemicals where
unsaturated  zone  considerations  are significant.   Both  lead  and B(A)P
allowable sludge  levels  reflect  the  shorter  unsaturated zone  travel
time.
                                  103

-------
                               Table 93.

     Effects of Increasing Depth to Groundwater from 0 to 1 Meter
                         at a  500 Meter Well.

 Sll-500,  GW-1M,  FOC-0.0001,  DIST=500M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
l.OOE-03
3.87E-01
1.03E-01
3.46E-04
8.54E-01
4.99E-03
3.00E-04
2.47E-01
1.65E-20
9.73E-03
O.OOE+00
4.00E-03
4.28E-04
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.06E+02
4.67E+01
l.OOE+04
2.48E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
1.76E+01
l.OOE+04
2.31E+02
3.98E-01
1.17E+03
2.13E+03
1.30E+03
1.52E+00
1.07E+02
4.70E+01
l.OOE+04
1.96E+03
l.OOE
l.OOE+04
1.16E+00
2.99E+02
8.65E+03
l.OOE+04
1.08E+03
3.98E-01
1.79E+03
2.13E+03
1.30E+03
1.52E+00
% DIFFERENCE
1.0 %
0.7 %
0.0 %
-21.2 %
0.0 %
0.0 %
0.0 %
0.0 %
48907.9 %
0.0 %
370.1 %
0.0 %
52.5 %
0.0 %
0.0 %
0.0 %
     This case is the same as S10-500 (Table 92) with an even shallower
depth to groundwater.   As expected,  the effects are  in  the chemicals
that gain  from  dispersion  and  retardation  in  the  unsaturated  zone
because of  small  release times compared to travel times or degradation.
BEHP gains  the most because of its very strong interactions with soil.
                                  104

-------
                               Table 94.

     Effects of Increasing Depth to Groundwater from 0 to 1 Meter
        and  Increasing Soil  Organic Content from 0.0001  to 0.01
                         at a  500  Meter Well.

 S12-500,  GW-1M,  FOC-0.01,  DIST=500M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.00E-02
l.OOE-02
3.87E-01
1.03E-01
3.46E-04
8.54E-01
4.99E-03
3.00E-04
2.47E-01
1.65E-20
9.73E-03
O.OOE+00
4.00E-03
4.28E-
5.00E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.06E+02
4.67E+01
l.OOE+04
2.48E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
1.76E+01
l.OOE+04
2.31E+02
3.98E-01
1.17E+03
2.13E+03
1.30E+03
1.52E+00
1.07E+02
4.70E+01
l.OOE+04
1.96E+03
l.OOE+04
l.OOE+04
1.16E+00
2.99E+02
9.26E+03
l.OOE+04
4.83E+03
3.98E-01
l.OOE+04
2.13E+03
1.30E+03
1.52E+00
% DIFFERENCE
1.0 %
0.8 %
0.0 %
-21.1 %
0.0 %
0.0 %
0.3 %
0.0 %
52405.7 %
0.0 %
1993.2 %
0.0 %
752.5 %
0.0 %
0.0 %
-0.1 %
     This case  is  the  same  as S10-500  (Table  92)  but with  a  greatly
reduced depth  to groundwater.   As expected,  the results  are  similar
between the two except  for lead,  which  reflects  some  of the difficulty
associated with the back calculation  for  allowable  sludge  levels.   All
other chemicals' risks  are driven  by  the  saturated  zone transport  and,
therefore, do not respond to the changes in the depth  to groundwater.
                                  105

-------
             Table  95.
Base Case for Well  at 1000 Meters.
B-1000
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
AQUIFER
4
8
2
4
2
5
4
3
2
0
8
0
2
4
2
5
.940E-02
.960E-03
.400E-01
.900E-02
.290E-04
.130.E-01
.990E-03
.010E-04
.480E-01
.OOOE+00
.020E-03
.OOOE+00
.560E-03
.410E-04
.890E-03
.OOOE-03
VAPOR
0
0
0
0
0
0
0
1
2
8
2
1
0
1
0
0
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.060E-12
.517E-04
.127E-06
.177E-03
.OOOE-04
.OOOE+00
.341E-05
.OOOE+00
.OOOE+00
BACKGRND
4
1
1
1
3
2
0
0
0
0
0
0
0
0
0
0
.OOOE-04
.OOOE-03
.OOOE-02
.OOOE-03
.OOOE-04
.700E-03
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
.OOOE+00
4
9
2
5
5
5
4
3
2
8
1
1
2
4
2
5
SUM
.980E-02
.960E-03
.500E-01
.OOOE-02
.290E-04
.157E-01
.990E-03
.010E-04
.483E-01
.127E-06
.020E-02
.OOOE-04
.560E-03
.544E-04
.890E-03
.OOOE-03

5
1
1
5
2
1
5
3
2
2
1
1
4
4
5
5
HEL
.OOOE-02
.OOOE-02
.300E+00
.OOOE-02
.OOOE-03
.750E+00
.OOOE-03
.OOOE-04
.480E-01
.100E-03
.020E-02
.OOOE-04
.OOOE-03
.540E-04
.OOOE-03
.OOOE-03
DRY WGHT
2.372E+02
1.042E+02
l.OOOE+04
6.354E+03
l.OOOE+04
l.OOOE+04
1.750E+00
4.514E+02
2.798E+01
l.OOOE+04
3.179E+03
1.186E+00
l.OOOE+04
3.313E+03
l.OOOE+04
2.293E+00
                106

-------
                               Table 96.

     Effects of Increasing Depth to Groundwater from 0 to 10 Meters
                         at a 1000 Meter Well.

 S7-1000,  GW=10M,  FOC-0.0001, DIST=1000M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
BASE CASE
CONG'S
(MG/L)
4.94E-02
l.OOE-03
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.38E+02
1.04E+02
l.OOE+04
7.68E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
l.OOE+04
l.OOE+04
l.OOE+04
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
% DIFFERENCE
0.1 %
0.1 %
0.0 %
20.9 %
0.0 %
0.0 %
0.0 %
0.0 %
35639.8 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
     The greatly  increased  distance between  source  and  exposure point
minimizes the importance of the unsaturated zone.  Only three chemicals
benefit from the  increased  depth; lead, BEHP,  and  DDT.   All  three are
slow moving in the unsaturated zone.  BEHP is sufficiently retarded for
the vapor pathway to become overriding.  Lead and DDT have sufficiently
short release times that the longer travel  time in the unsaturated zone
results in more dispersion in the aquifer.
                                  107

-------
                               Table 97.

    Effects of Increasing Depth to  Groundwater from 0 to 10 Meters
        and  Increasing Soil  Organic Content from  0.0001  to  0.01
                         at  a 1000 Meter Well.

 S8-1000,  GW=10M,  FOC=0.01,  DIST=1000M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-03
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
M9E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.38E+02
1.04E+02
l.OOE+04
7.68E+03
l.OOE+04
l.OOE+04
1.76E+00
7.39E+02
l.OOE+04
l.OOE+04
l.OOE+04
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
3.25E+00
% DIFFERENCE
0.1 %
0.1 %
0.0 %
20.8 %
0.0 %
0.0 %
0.3 %
63.7 %
35639.8 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
41.7 %
     This case is the same  as  S7-1000  (Table 96)  except for the higher
soil  organic content.  The greater organic levels slow down unsaturated
transport even  further.    The  effect  is  to  delay  organic  chemicals
sufficiently  that   B(A)P   and   toxaphene  benefit   from  additional
dispersion  as  the lead  and DDT had already.   In  essence,  the higher
organic content  has  raised the relative importance  of the unsaturated
zone  vis a vis the saturated transport for B(A)P and toxaphene.
                                  108

-------
                               Table 98.

     Effects of Increasing Depth to Groundwater from 0 to 15 Meters
                         at a 1000 Meter Well.

 S9-1000,  GW=5M,  FOC-0.0001,  DIST=1000M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-03
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.38E+02
1.04E+02
l.OOE+04
7.13E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
l.OOE+04
l.OOE+04
l.OOE+04
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
% DIFFERENCE
0.2 %
0.2 %
0.0 %
12.2 %
0.0 %
0.0 %
0.0 %
0.0 %
35639.8 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
     This case  is the  same as  S7-1000  (Table 96)  but with  half  the
depth to groundwater.  The results are almost identical  except that  the
allowable levels  for lead are  decreased  due to less unsaturated  zone
travel  time and,  hence,  less dispersion.   The  effects  on  BEHP and  DDT
are unchanged because  the maximum impact has  already been  reached  and
is not  affected by further delays in unsaturated transport.
                                  109

-------
                               Table 99.

     Effects of Increasing Depth to Groundwater from 0 to 5 Meters
        and Increasing Soil Organic Content from 0.0001 to 0.01
                         at a 1000 Meter Well.

 S10-1000,  GW=5M,  FOC-0.01, DIST=1000M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-03
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.38E+02
1.04E+02
l.OOE+04
7.12E+03
l.OOE+04
l.OOE+04
1.76E+00
5.05E+02
l.OOE+04
l.OOE+04
l.OOE+04
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.43E+00
% DIFFERENCE
0.2 %
0.1 %
0.0 %
12.1 %
0.0 %
0.0 %
0.3 %
11.8 %
35639.8 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
5.9 %
     This case  is the  same as  S9-1000  (Table 98)  except for  a  much
higher soil  organic content.   Once  again,  the saturated zone transport
considerations are overriding  here for  all  but a  few  chemicals.   For
three of these,  lead,  BEHP, and DDT, the effect of the unsaturated zone
is realized  with  a 5  meter depth  and remains virtually  unchanged  at
greater  depths   to  groundwater.    B(A)P   and  toxaphene  have  higher
allowable sludge  concentrations  because  the larger organic  fraction
delays transport enough to benefit from added dispersion.
                                  110

-------
                              Table  100.

      Effects of Increasing Depth to Groundwater from 0 to 1  Meter
                         at a 1000 Meter Well.

 Sll-1000,  GW=1M,  FOC=0.0001, DIST=1000M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-03
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.36E+02
1.04E+02
l.OOE+04
6.36E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
l.OOE+04
l.OOE+04
8.22E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
% DIFFERENCE
-0.5 %
0.1 %
0.0 %
0.1 %
0.0 %
0.0 %
0.0 %
0.0 %
35639.8 %
0.0 %
158.6 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
     This case  is  the  same  as  S9-1000  (Table  98)  but  has an  even
shallower unsaturated zone.  Once again, the effect is limited to a few
organics where delayed  transport  is of significance.   One  of these is
BEHP which becomes a vapor  hazard  because of the slow unsaturated zone
transport velocity.   The other  is  DDT which undergoes  dispersion  and
dilution because the release time is short compared to the travel time.
                                  Ill

-------
                              Table 101.

     Effects of Increasing Depth to Groundwater from 0 to 1 Meter
        and  Increasing Soil  Organic Content from 0.0001  to  0.01
                         at  a 1000  Meter Well.

 S12-1000, GW=1M,  FOO0.01,  DIST=1000M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
T.OOE-03
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.37E+02
1.04E+02
l.OOE+04
6.36E+03
l.OOE+04
l.OOE+04
1.76E+00
4.51E+02
l.OOE+04
l.OOE+04
l.OOE+04
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
% DIFFERENCE
-0.3 %
0.0 %
0.0 %
0.1 %
0.0 %
0.0 %
0.3 %
-0.2 %
35639.8 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.1 %
     This  case  is  the  same as  Sll-1000  (Table  100)  only the  soil
organic content is higher  and,  therefore,  retains  organic contaminants
longer.  The results  are virtually identical with the exception  of DDT.
DDT has a  higher  allowable sludge concentration for  this  case  because
the slower  unsaturated zone  transport  results  in greater dispersion.
For all  other chemicals the  unsaturated depth  is  too thin  to  impact
final  concentrations  in any substantial  way.
                                  112

-------
                              Table  102.

           Effects of Reducing  Recharge  from 0.5 to 0.25 m/y
                        for  a Well  at  50  Meters.

 S13-50,  RECHARGE = 0.25 M/Y,  DIST = 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.2821E+00
2.8324E+00
l.OOOOE+04
2.3366E+02
l.OOOOE+04
l.OOOOE+04
1.2877E+00
4.5211E+02
2.1383E+01
l.OOOOE+04
9.5722E+00
2.1960E-02
2.8535E+01
1.2920E+03
4.2442E+01
1.6835E+00
2.3 %
3.1 %
0.0 %
-2.4 %
0.0 %
0.0 %
100.0 %
100.1 %
96.0 %
0.0 %
95.7 %
0.0 %
99.7 %
37.6 %
100.6 %
100.0 %
     This case reflects the impacts of reduced recharge on the movement
of chemicals.   Mechanistically speaking, the smaller amount of recharge
extends the release time (takes longer to dissolve out the inventory of
chemical)  and  leads to  greater  levels  of  dilution since the  flux is
reduced.
     The   effects  of  reduced  flux  are  not seen  with the  inorganics
because  their  aquifer  concentrations  are determined  by  solubility
constraints.    Hence,  all  of  the  chemical  brought  down with  higher
recharge  levels was  not  solubilized.    In fact,  the amount solubilized
is  less  than  one  half and  hence,  the  100% change.    Chlordane  is
unaffected  because  it  was  already  at  the  10,000  mg/kg  maximum.
Degradation dominates dilution effects and so is unchanged by the lower
recharge.
                                  113

-------
                              Table  103.

           The Effect of Minimal  Recharge at a 50 Meter Well.

 S14-50,  RECHARGE = 0.00635 M/Y,  DIST = 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
2.5446E+02
l.OOOOE+04
l.OOOOE+04
3.2193E+01
l.OOOOE+04
2.6096E+02
l.OOOOE+04
1.3070E+02
2.1960E-02
7.1338E+02
2.0300E+03
1.0611E+03
4.2088E+01
% DIFFERENCE
162777.1 %
363920.2 %
0.0 %
6.3 %
0.0 %
0.0 %
4900.8 %
4326.7 %
2291.7 %
0.0 %
2571.6 %
0.0 %
4893.6 %
116.3 %
4914.9 %
4901.0 %
     This case reflects  the  effects  of drastic  reductions  in recharge.
The greatly restricted flux of contaminant is subject to dispersion and
dilution in  the  aquifer.   The  only  chemicals  not  effected  are  those
already at  the maximum allowable sludge  concentration  of  10,000  mg/kg
(Copper, Mercury, and  Nickel)  and the  chemicals  with vapor driver risk
such  as Chlordane  and  DMN.    The  solubility   constraints  are  still
controlling  for   lead,   but  not  for  soluble Arsenic  and  Chlordane.
Hence, the big increases  in  allowable  sludge levels  for the latter two
inorganics.    Most  organics  not at  maximum  allowable sludge  levels
reflect a change of 4000% to  5000% reflecting  the  flux change due  to
cutting recharge  from 0.5 to 0.00635 m/yr.
                                  114

-------
                              Table 104.

        The Effect of Decreasing Recharge from 0.5 to 0.25 M/Y
                          at a 150  Meter Well

 S13-150,  RECHARGE =  0.25 M/Y, DIST =  150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
3.6141E+01
1.6279E+01
l.OOOOE+04
4.9116E+02
l.OOOOE+04
l.OOOOE+04
1.6997E+00
5.0033E+02
2.7664E+01
l.OOOOE+04
2.3364E+01
7.0109E-02
9.7019E+01
2.4085E+03
1.0271E+02
1.8619E+00
52.5 %
72.1 %
0.0 %
1.8 %
0.0 %
0.0 %
100.0 %
100.1 %
98.3 %
0.0 %
35.9 %
0.0 %
96.9 %
63.6 %
100.0 %
67.3 %
     The case  illustrates  the effect  of reducing  recharge when  the
exposure point  is  distant  from  the source.    It  is analogous to  case
S13-50  (Table  102)  but  with  a longer  travel  path in  the  unsaturated
zone.   The  same  chemicals are impacted in both cases,  but  the  impacts
are greater for this case  where  the  distance  is larger.   This  is
because the longer distance  makes the travel time  greater  relative  to
the release time which  leaves more room  for dispersion  to  reduce  peak
heights,  hence,  the  longer  travel  distance   accommodates   larger
allowable sludge concentrations,  just as the  base case at  150  meters
has larger  allowable  sludge  levels  than  the  base case at  50  meters.
Copper,  Mercury,  Nickel,  and Chlordane  were  already  at  the  maximum
allowable sludge concentration of 10,000 mg/kg  in  the  base  case.
                                  115

-------
                              Table 105.

      The Effects of  Decreasing  Recharge  from 0.5 to 0.00635 M/Y
                          at a 150 Meter Well

 S14-150,  RECHARGE = 0.00635 M/Y, DIST = 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
1.0560E+03
l.OOOOE+04
l.OOOOE+04
3.5533E+01
l.OOOOE+04
4.3248E+02
l.OOOOE+04
3.5679E+02
7.0112E-02
2.4599E+03
6.2034E+03
2.5630E+03
4.6558E+01
% DIFFERENCE
42108.3 %
105618.3 %
0.0 %
111.2 %
0.0 %
0.0 %
4081.2 %
3898.9 %
3000.4 %
0.0 %
1975.9 %
0.0 %
4893.5 %
321.5 %
4890.6 %
4082.4 %
     This  case  illustrates   the  effects  of  a  drastic  reduction  of
recharge.  It resembles case S14-50 (Table 103) but has a longer travel
distance in  the  saturated  zone.   The  same  chemicals  are  affected,  but
the net effect compared to the base case is of a lower magnitude.   This
is because the  extremely  small  amount of recharge  predominates  as  the
determinant  of  exposure  levels  rather  than  the  saturated  travel
distance.    The  allowable  concentrations  between  the  two cases  are
similar, but  because the base case allowable levels are greater for the
150 meter  travel  distance, the  percentage  changes are smaller.   When
compared to  S13-150  (Table 104)  the  allowable  levels  are dramatically
higher reflecting  the  greatly increased dilution  for  the small  amount
of recharge in the system.   Copper,  Mercury, Nickel, and Chlordane were
already  at the maximum  sludge  concentrations  of  10,000  mg/kg  in  the
case.
                                  116

-------
                              Table  106.

         The Effect of  Reduced  Recharge  for a 500 Meter Well.

 S13-500,  500 M BASE CASE BUT WITH R = 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
1.9913E+02
7.4517E+01
l.OOOOE+04
2.3956E+03
l.OOOOE+04
l.OOOOE+04
2.3174E+00
5.9778E+02
3.8197E+01
l.OOOOE+04
4.4047E+02
3.9816E-01
1.7594E+03
4.0350E+03
2.6070E+03
3.0356E+00
88.1 %
59.6 %
0.0 %
14.2 %
0.0 %
0.0 %
100.0 %
100.0 %
116.6 %
0.0 %
91.0 %
0.0 %
100.0 %
89.4 %
100.0 %
100.0 %
     The  case  illustrates  the effect  of  reducing  recharge when  the
exposure  point  is distant  from the source.   It is analogous  to  case
S13-50  (Table  102)  but  with  a  much  longer  travel   path  in   the
unsaturated zone.   The  same chemicals are  impacted  in  both  cases,  but
the impacts  are  greater  for this  case  where the distance  is  larger.
This  is  because  the longer distance  makes  the  travel  time  greater
relative to the  release  time which leaves  more  room for  dispersion to
reduce peak  heights, hence,  the  longer  travel  distance  accommodates
larger allowable  sludge  concentrations,  just as  the base case  at  500
meters has  larger  allowable sludge  levels than the  base  case at 50
meters.    Copper,  Mercury,  Nickel,  and Chlordane  were  already  at  the
maximum  allowable  sludge  concentration of 10,000  mg/kg  in the  base
case.
                                  117

-------
                              Table  107.

         The Effect of Minimal  Recharge  at  a  500 Meter Well.

 S14-500,  500 M BASE CASE BUT WITH R = 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.8390E+03
l.OOOOE+04
l.OOOOE+04
4.2443E+01
l.OOOOE+04
6.5232E+02
l.OOOOE+04
3.7655E+03
3.9816E-01
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
5.5597E+01
% DIFFERENCE
9348.2 %
21319.2 %
0.0 %
226.1 %
0.0 %
0.0 %
3563.0 %
3245.7 %
3598.4 %
0.0 %
1532.8 %
0.0 %
1036.8 %
369.5 %
667.2 %
3563.0 %
     This  case  illustrates   the  effects  of  a  drastic  reduction  of
recharge.  It resembles case S14-50 (Table 103) but has a longer travel
distance in  the  saturated  zone.   The  same  chemicals  are  affected,  but
the net effect compared to the base case is of a lower magnitude.   This
is because the  extremely  small  amount of  recharge  predominates  as  the
determinant  of  exposure  levels  rather  than  the  saturated  travel
distance.    The  allowable  concentrations  between  the  two cases  are
similar, but  because the base case allowable levels are greater for the
500 meter  travel  distance, the  percentage  changes are smaller.   When
compared to  S13-500  (Table 106)  the  allowable  levels  are dramatically
higher reflecting  the  greatly increased dilution  for  the small  amount
of recharge in the system.   Copper, Mercury, Nickel, and Chlordane were
already  at the maximum  sludge  concentrations  of  10,000  mg/kg  in  the
case.
                                  118

-------
                              Table 108.

         The Effect of Reduced Recharge at a 1000 Meter Well.

 S13-1000,  1000 M BASE CASE BUT WITH R = 0.25 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3709E+02
1.0423E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7503E+00
4.5136E+02
2.7927E+01
l.OOOOE+04
3.1791E+03
1.1857E+00
l.OOOOE+04
3.3130E+03
l.OOOOE+04
2.2927E+00
4.5922E+02
2.1568E+02
l.OOOOE+04
7.3340E+03
l.OOOOE+04
l.OOOOE+04
3.5006E+00
9.0118E+02
4.8743E+01
l.OOOOE+04
5.2431E+03
1.1857E+00
l.OOOOE+04
6.4324E+03
l.OOOOE+04
4.5855E+00
93.7 %
106.9 %
0.0 %
15.0 %
0.0 %
0.0 %
100.0 %
99.7 %
74.5 %
0.0 %
64.9 %
0.0 %
0.0 %
94.2 %
0.0 %
100.0 %
     This case  is  the same  as  case S13-500 (Table  106) with  a larger
distance between the source and the exposure point.  The same chemicals
are  affected  at  about  the  same  order  of magnitude.   However,  the
overall  effect  is  greater  in this case  because the  longer saturated
zone  travel  path  increases  the  travel  time  to  release   time  ratio
providing more opportunity for dispersion to reduce peak heights.
                                  119

-------
                              Table 109.

         The Effect of Minimal Recharge at a 1000 Meter Well.

 S14-1000,  1000 M BASE CASE BUT WITH R = 0.00635 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3709E+02
1.0423E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7503E+00
4.5136E+02
2.7927E+01
l.OOOOE+04
3.1791E+03
1.1857E+00
l.OOOOE+04
3.3130E+03
l.OOOOE+04
2.2927E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.4113E+01
l.OOOOE+04
1.0239E+03
l.OOOOE+04
l.OOOOE+04
1.1857E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
8.3983E+01
% DIFFERENCE
4117.8 %
9494.2 %
0.0 %
56.7 %
0.0 %
0.0 %
3563.0 %
2115.5 %
3566.3 %
0.0 %
214.6 %
0.0 %
0.0 %
201.8 %
0.0 %
3563.1 %
     This  case   is  the  same  as  S14-500  (Table  107)  with  a  greater
distance  between the  source  and  point  of  exposure.   The  allowable
sludge  concentrations  are  comparable  between  the  two  because  the
dispersion and dilution associated with the distance is  large enough to
predominate risks  and the maximum  level  in  sludge of  10^  is  reached.
Because the base case for  1000  meters is higher than  for  500  meters,
the  percentage   increase  over  the  base  case  is   smaller   (i.e.,  the
numerator is the same but the denominator is  larger).
                                  120

-------
                              Table 110.

               The Effect of Higher Groundwater Velocity
                          at a 50 Meter Well.
 S15-50,  GW VEL 1000 M/Y,  DIST 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
2.3461E+02
l.OOOOE+04
l.OOOOE+04
6.4376E+00
2.2666E+03
8.8013E+01
7.5610E+03
2.2275E+01
2.1960E-02
5.8132E+01
1.8540E+03
1.0372E+02
8.4160E+00
% DIFFERENCE
162777.1 %
363920.2 %
0.0 %
-2.0 %
0.0 %
0.0 %
900.0 %
903.4 %
706.6 %
-24.4 %
355.3 %
0.0 %
306.9 %
97.5 %
390.2 %
900.0 %
     This case  illustrates  the effect of  increasing  aquifer  velocity.
In essence,  the higher velocity means  more water  passes  under the site
in a year.   Since the flux  remains  constant  with  the set  recharge,the
higher velocity  translates  to  greater dilution  potential  and  hence,
higher  allowable  sludge  concentrations.     No  effect   is  seen  for
geochemically  controlled  contaminants which  are  already  at  maximum
sludge levels  (Copper,  Mercury,  and Nickel)  or  for  DMN whose  sludge
level  is  determined by vapor considerations.
                                  121

-------
                              Table 111.

           The Effect of Lower Velocity at a 50 Meter Well.

 S16-50,  GW VEL 10 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
5.9943E+00
2.7471E+00
l.OOOOE+04
2.3414E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
1.7754E+02
2.1959E-02
1.8938E+03
9.3867E+02
2.1287E+03
8.4160E-01
% DIFFERENCE
-2.4 %
0.0 %
0.0 %
-2.2 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
3529.0 %
0.0 %
13156.3 %
0.0 %
9960.5 %
0.0 %
     This case  illustrates  the effect of a  lower  groundwater  velocity
and,  hence, less  water  is available each year  to  receive  and  mix  with
the  recharge.     The  net  effect  is  less  dilution  potential   and,
therefore,  lower  allowable  sludge  levels.   The major effect  is  noted
for those chemicals.   For Lindane, DDT,  and  TCE,  the velocity creates
longer travel  times over which more degradation occurs.  Therefore,  the
allowable sludge  levels  are  higher.   Allowable  sludge  concentrations
also  increase for DDT and TCE.   Two other chemicals,  Chlordane and DDT
also  undergo degradation, but their other risks are determined  by  vapor
considerations  at this distance.
                                  122

-------
                              Table 112.

              The Effect of Minimal Groundwater Velocity
                          at a 50 Meter Well.
 S17-50,  GW VEL 1 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.2593E+00
3.0775E+00
l.OOOOE+04
2.4620E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
2.7593E+02
2.1959E-02
l.OOOOE+04
9.3867E+02
l.OOOOE+04
8.4160E-01
% DIFFERENCE
1.9 %
12.0 %
0.0 %
2.8 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
5540.2 %
0.0 %
69898.6 %
0.0 %
47161.2 %
0.0 %
     This case is analogous to  S16-50  (Table  111)  with  an  even smaller
groundwater velocity.   As a consequence, the  degradable organics  have
longer  to  undergo  degradation.   See  discussion  in Table  111.    The
slight  change  in Cadmium reflects  the  difficulty in  matching  sludge
values exactly with  the back calculation method.
                                  123

-------
                              Table 113.

               The  Effect  of Higher Velocity  Groundwater
                         at a 150 Meter Well.
 S15-150,  GW VEL 1000 M/Y,  DIST = 150  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.QOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
8.7193E+02
l.OOOOE+04
l.OOOOE+04
7.1070E+00
2.4999E+03
1.0971E+02
l.OOOOE+04
2.8337E+01
7.0112E-02
8.7089E+01
4.9135E+03
1.2527E+02
9.3097E+00
% DIFFERENCE
42108.3 %
105618.3 %
0.0 %
74.4 %
0.0 %
0.0 %
736.3 %
899.7 %
686.5 %
0.0 %
64.9 %
0.0 %
76.8 %
233.8 %
143.9 %
736.3 %
     This  case illustrates the effect of  higher  groundwater  velocities
and is  analogous  to S15-50.   See  Table 110.
                                  124

-------
                              Table 114.

              The Effect of Reduced Groundwater Velocity
                         at a 150 Meter Well.
 S16-150,  GW  VEL  10 M/Y,  DIST 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
2.4492E+01
9.6872E+00
l.OOOOE+04
5.9358E+02
l.OOOOE+04
l.OOOOE+04
8.5012E-01
2.4999E+02
1.3935E+01
l.OOOOE+04
8.7101E+02
7.0112E-02
l.OOOOE+04
1.4715E+03
l.OOOOE+04
1.1136E+00
% DIFFERENCE
3.4 %
2.4 %
0.0 %
18.7 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
4967.8 %
0.0 %
20199.6 %
0.0 %
19371.5 %
0.0 %
     This case is analogous to S16-50  at  a  slower  velocity.   See  Table
111.   The slight increase  for  lead  reflects  the  difficulty  in matching
sludge concentrations exactly with the back calculation  method.
                                  125

-------
                              Table 115.

                The Effect of Minimal  Groundwater Flow
                          at  a 150 Meter Well.
 S17-150,  GW VEL 1 M/Y,  DIST 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
2.3630E+01
9.5421E+00
l.OOOOE+04
6.8834E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3945E+01
l.OOOOE+04
8.8095E+02
7.0109E-02
l.OOOOE+04
1.4711E+03
l.OOOOE+04
1.1132E+00
% DIFFERENCE
-0.3 %
0.9 %
0.0 %
37.7 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
5025.7 %
0.0 %
20199.6 %
0.0 %
19371.5 %
0.0 %
     This case  is the  same  as S17-50.   See discussion on  Table  111.
Note  the  allowable   sludge   levels   are  even  higher  for  degradable
chemicals  because   of   the    additional  travel   times   during   which
degradation will  occur.   The lead values appear  to  be  a  reflection  of
inaccuracies  in  the  back  calculation method.   Lead is  controlled  by
solubility limitations in this setting.
                                  126

-------
                                Table 116.

               The Effect of Higher Groundwater Velocity
                         at a 500 Meter Well.

 S15-500,  500 M BASE CASE BUT VEL  1000 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
4.1026E+03
l.OOOOE+04
l.OOOOE+04
8.5012E+00
2.9879E+03
1.8773E+02
l.OOOOE+04
4.7951E+01
3.9817E-01
1.7202E+02
l.OOOOE+04
2.0672E+02
1.1109E+01
% DIFFERENCE
9348.2 %
21319.2 %
0.0 %
95.7 %
0.0 %
0.0 %
633.7 %
899.7 %
964.3 %
0.0 %
-79.2 %
0.0 %
-80.4 %
369.5 %
-84.1 %
631.9 %
     This  case   illustrates  the  effect  of  higher  velocities  and  is
analogous to S15-50.  See Table 110.  The reduced sludge concentrations
for DDT, Lindane  and  TCE reflect the  lower  amount  of degradation  that
will  occur because of the shorter travel times.
                                  127

-------
                              Table  117.

               The  Effect  of  Lower Groundwater Velocity
                        at a 500 Meter Well.

S16-500, 500 M BASE CASE BUT VEL = 10 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
1.0676E+02
4.7022E+01
l.OOOOE+04
1.9345E+03
l.OOOOE+04
l.OOOOE+04
1.1591E+00
2.9879E+02
1.7669E+01
l.OOOOE+04
5.0029E+03
3.9817E-01
l.OOOOE+04
2.1310E+03
l.OOOOE+04
1.5176E+00
0.9 %
0.7 %
0.0 %
-7.7 %
0.0 %
0.0 %
0.0 %
0.0 %
0.2 %
0.0 %
2069.4 %
0.0 %
1036.8 %
0.1 %
667.2 %
0.0 %
    This case  is  similar  to  S16-50.  See Table 111.
                                  128

-------
                             Table  118.

              The  Effect  of  Minimal  Groundwater Velocity
                         at  a 500  Meter Well.

S17-500, 500 M BASE CASE BUT VEL = 1 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
1.0676E+02
4.7022E+01
l.OOOOE+04
1.9332E+03
l.OOOOE+04
l.OOOOE+04
1.1591E+00
2.9879E+02
1.7669E+01
l.OOOOE+04
5.0029E+03
3.9817E-01
l.OOOOE+04
2.1310E+03
l.OOOOE+04
1.5176E+00
0.9 %
0.7 %
0.0 %
-7.8 %
0.0 %
0.0 %
0.0 %
0.0 %
0.2 %
0.0 %
2069.4 %
0.0 %
1036.8 %
0.1 %
667.2 %
0.0 %
    This case  is similar to S16-50.  See Table 111.
                                  129

-------
                              Table  119.

              The Effect of Higher Groundwater Velocity
                        at a  1000 Meter Well.

S15-1000, 1000 M BASE CASE BUT VEL 1000 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3709E+02
1.0423E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7503E+00
4.5136E+02
2.7927E+01
l.OOOOE+04
3.1791E+03
1.1857E+00
l.OOOOE+04
3.3130E+03
l.OOOOE+04
2.2927E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
8.8982E+03
l.OOOOE+04
l.OOOOE+04
1.7492E+01
4.5121E+03
2.8727E+02
l.OOOOE+04
1.1528E+02
1.1857E+00
4.1598E+02
l.OOOOE+04
4.9692E+02
2.2952E+01
% DIFFERENCE
4117.8 %
9494.2 %
0.0 %
39.5 %
0.0 %
0.0 %
899.4 %
899.7 %
928.6 %
0.0 %
-96.4 %
0.0 %
-95.8 %
201.8 %
-95.0 %
901.1 %
    This case is similar to S15-50.  See Table 110 and Table 116
                                  130

-------
                              Table 120.

               The Effect of  Lower Groundwater Velocity
                         at  a 1000 Meter Well.

 S16-1000,  1000 M BASE CASE  BUT VEL = 10 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3709E+02
1.0423E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7503E+00
4.5136E+02
2.7927E+01
l.OOOOE+04
3.1791E+03
1.1857E+00
l.OOOOE+04
3.3130E+03
l.OOOOE+04
2.2927E+00
2.3722E+02
1.0428E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7509E+00
4.5121E+02
2.7882E+01
l.OOOOE+04
l.OOOOE+04
1.1857E+00
l.OOOOE+04
3.3117E+03
l.OOOOE+04
2.2924E+00
0.1 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.2 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
     This case  is similar  to S16-50.   See Table  111.    It  should  be
noted,  however,  that the  travel  distance  is  so large that  the  extra
travel  time  for degradables has become insignificant because the sludge
concentrations for Lindane and TCE have reached the maximum level.
                                  131

-------
                              Table  121.

              The  Effect  of  Minimal  Groundwater Velocity
                        at a  1000 Meter Well.

S17-1000, 1000 M BASE CASE BUT VEL = 1 M/Y
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3709E+02
1.0423E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7503E+00
4.5136E+02
2.7927E+01
l.OOOOE+04
3.1791E+03
1J857E+00
l.OOOOE+04
3.3130E+03
l.OOOOE+04
2.2927E+00
2.3722E+02
1.0428E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7509E+00
4.5121E+02
2.7882E+01
l.OOOOE+04
l.OOOOE+04
1.1857E+00
l.OOOOE+04
3.3146E+03
l.OOOOE+04
2.2924E+00
0.1 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.2 %
0.0 %
214.6 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
    This case  is  similar to S16-1000.  See Table 120.
                                  132

-------
                              Table 122.

                  The Effect of a Very Thick Aquifer
                          at a 50 Meter Well.

 S18-50,  AQUIFER THICKNESS = 560M,  DIST = 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY %
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
5.8201E+00
2.6302E+00
l.OOOOE+04
2.3343E+02
l.OOOOE+04
l.OOOOE+04
6.7523E-01
2.3757E+02
1.1471E+01
l.OOOOE+04
5.0370E+00
2.1961E-02
1.4748E+01
9.6306E+02
2.1855E+01
8.8296E-01
DIFFERENCE
-5.2 %
-4.3 %
0.0 %
-2.5 %
0.0 %
0.0 %
4.9 %
5.2 %
5.1 %
0.0 %
3.0 %
0.0 %
3.2 %
2.6 %
3.3 %
4.9 %
     This case illustrates the effect of a thicker aquifer on allowable
concentrations.   THere are no  effects  on  chemicals  controlled  by  vapor
considerations  or  those  that  are  already  at  the maximum  allowable
sludge  concentrations.    For  all  others,   the  effects  are  small,
indicating that  vertical  dispersion is not  a  real  limitation  for  the
base  case.    The  negative   values   for metals  are  indicative   of
inaccuracies  in the   back  calculation  method  for setting  allowable
sludge levels.
                                  133

-------
                              Table 123.

                     The Effect  of a Thick Aquifer
                          at a 50 Meter Well.

 S19-50,  AQUIFER THICKNESS = 78.6M,  DIST = 50  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY %
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.1382E+00
2.7461E+00
l.OOOOE+04
2.3929E+02
l.OOOOE+04
l.OOOOE+04
6.7523E-01
2.3757E+02
1.1471E+01
l.OOOOE+04
4.9948E+00
2.1961E-02
1.4748E+01
9.6255E+02
2.1855E+01
8.8296E-01
DIFFERENCE
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
4.9 %
5.2 %
5.1 %
0.0 %
2.1 %
0.0 %
3.2 %
2.5 %
3.3 %
4.9 %
     This case is the same as S18-50 with the thinner aquifer but still
thicker  than  the base  case.    The  results are virtually  identical  to
S18-50. See Table 122.
                                  134

-------
                              Table  124.

                     The Effect of a Thin Aquifer
                          at a 50 Meter Well.

 S20-50,  AQUIFER THICKNESS = 5M, DIST = 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.0825E+00
2.7370E+00
1.4983E+03
2.3912E+02
l.OOOOE+04
6.0132E+02
2.6957E-01
9.4915E+01
4.5045E+00
l.OOOOE+04
2.2131E+00
2.1961E-02
6.1771E+00
5.3348E+02
9.5351E+00
3.5321E-01
-0.9 %
-0.4 %
-85.0 %
-0.1 %
0.0 %
-94.0 %
-58.1 %
-58.0 %
-58.7 %
0.0 %
-54.8 %
0.0 %
-56.8 %
-43.2 %
-54.9 %
-58.0 %
     This case  illustrates the  effect of  reducing  aquifer thickness.
Aside  from  chemicals  already  at  maximum  allowable  sludge  levels
(Mercury  and   Chlordane)   and  DMN   which   is   controlled  by  vapor
considerations,  the  chemicals respond with  a  reduced  allowable sludge
concentration because  of  the  restriction  on vertical  dispersion caused
by thinning the aquifer.
                                  135

-------
                              Table  125.

                  The  Effect of  a Very Thick Aquifer
                          at a 150 Meter Well.

 S18-150,  AQUIFER THICKNESS = 560M,  DIST = 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.O.OOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
2.4177E+01
9.5853E+00
l.OOOOE+04
4.7115E+02
l.OOOOE+04
l.OOOOE+04
1.7591E+00
4.8860E+02
2.8669E+01
l.OOOOE+04
3.1010E+01
7.0112E-02
8.9228E+01
2.3724E+03
9.3540E+01
2.3049E+00
2.0 %
1.3 %
0.0 %
-5.8 %
0.0 %
0.0 %
107.0 %
95.4 %
105.5 %
0.0 %
80.4 %
0.0 %
81.1 %
61.2 %
82.1 %
107.1 %
     This case  is  similar to  S18-50  but for a  greater  saturated  zone
travel  distance.  The  impacts  are  much greater  in this case because at
the  longer  distances,  the  vertical  dispersion  goes  to much  greater
depths.    Hence,  species  not  controlled  by  vapor considerations  or
geochemistry,   or those  for  which sludge  concentrations  are  already
maximized,  benefit from the greater volume of groundwater for dilution.
                                  136

-------
                              Table 126.

                     The Effect  of a  Thick  Aquifer
                         at a 150 Meter Well.

 S19-150,  AQUIFER THICKNESS =  78.6M,  DIST = 150  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
2.4214E+01
9.6016E+00
l.OOOOE+04
5.6360E+02
l.OOOOE+04
l.OOOOE+04
1.7641E+00
4.8816E+02
2.8637E+01
l.OOOOE+04
3.1007E+01
7.0115E-02
8.9247E+01
2.3725E+03
9.3397E+01
2.3114E+00
2.2 %
1.5 %
0.0 %
12.7 %
0.0 %
0.0 %
107.6 %
95.2 %
105.3 %
0.0 %
80.4 %
0.0 %
81.2 %
61.2 %
81.9 %
107.6 %
     This case  is  analogous  to  S18-50  with a  thinner  aquifer.    The
impacts are nearly  identical  since 78.6 meters of thickness  is  enough
to allow the extra vertical dispersion.  See Table 125.
                                  137

-------
                              Table 127.

                     The Effect of a Thin Aquifer
                         at a 150 Meter Well.

 S20-150,  AQUIFER THICKNESS =  5M,  DIST = 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
1.4599E+01
6.5689E+00
2.8392E+03
5.2106E+02
l.OOOOE+04
1.0406E+03
2.8362E-01
8.3209E+01
4.6764E+00
l.OOOOE+04
5.8182E+00
7.0115E-02
1.6410E+01
5.7531E+02
1.7106E+01
3.7087E-01
-38.4 %
-30.6 %
-71.6 %
4.2 %
0.0 %
-89.6 %
-66.6 %
-66.7 %
-66.5 %
0.0 %
-66.1 %
0.0 %
-66.7 %
-60.9 %
-66.7 %
-66.7 %
     This case is similar to S20-50.  The longer distance provides more
longitudinal  dispersion  but  makes  the  thin  aquifer more  restrictive
with respect to vertical  dispersion.  See Table 124.
                                  138

-------
                              Table 128.

                  The Effect of a Very Thick Aquifer
                         At a 500 Meter Well.

 S18-500,  500 M BASE CASE BUT WITH AQUIFER THICKNESS = 560  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
6.4628E+02
2.2284E+02
l.OOOOE+04
2.1034E+03
l.OOOOE+04
l.OOOOE+04
7.1950E+00
1.8368E+03
7.5537E+01
l.OOOOE+04
1.0726E+03
1.1857E+00
4.0420E+03
l.OOOOE+04
7.7178E+03
9.4274E+00
510.6 %
377.3 %
0.0 %
0.3 %
0.0 %
0.0 %
521.0 %
514.5 %
328.3 %
0.0 %
365.1 %
197.8 %
359.5 %
369.5 %
492.1 %
521.1 %
     This case  is  the  same as  S18-50  but with  a much  longer  travel
distance.   As  a  consequence,  the  vertical  dispersion potential  is
greater  and a  thin  aquifer has  a  greater  confining  influence.   Hence,
the allowable sludge concentrations are much higher here.
                                  139

-------
                              Table 129.

                     The Effect  of a Thick Aquifer
                         at a 500 Meter Well.

 S19-500,  500 M BASE CASE BUT WITH AQUIFER THICKNESS  =  78.6  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
5.9758E+02
2.5547E+02
l.OOOOE+04
2.2659E+03
l.OOOOE+04
l.OOOOE+04
5.8030E+00
1.5176E+03
6.9544E+01
l.OOOOE+04
8.9198E+02
3.9819E-01
3.8635E+03
8.7953E+03
6.5958E+03
7.5881E+00
464.6 %
447.2 %
0.0 %
8.1 %
0.0 %
0.0 %
400.8 %
407.7 %
294.3 %
0.0 %
286.8 %
0.0 %
339.2 %
312.9 %
406.0 %
399.9 %
     This  case  is  the  same  as  S19-50  at  a  longer travel  distance.
Therefore, the  benefits are  similar but  larger  in magnitude  since  a
thin aquifer is more confining at greater distances.  See Table 123.
                                  140

-------
                              Table 130.

                     The Effect of a Thin Aquifer
                         at a 500 Meter Well.

 S20-500,  500 M BASE CASE BUT WITH AQUIFER THICKNESS = 5 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
3.4302E+01
1.5721E+01
l.OOOOE+04
1.7366E+03
l.OOOOE+04
4.3817E+03
3.8687E-01
9.9624E+01
5.8877E+00
l.OOOOE+04
7.9240E+01
3.9819E-01
2.9324E+02
7.3865E+02
4.3508E+02
5.0655E-01
-67.6 %
-66.3 %
0.0 %
-17.2 %
0.0 %
-56.2 %
-66.6 %
-66.7 %
-66.6 %
0.0 %
-65.6 %
0.0 %
-66.7 %
-65.3 %
-66.6 %
-66.6 %
     This case  is  the  same  as  S20-150  but  the travel  distances  are
greater.   While a  thin  aquifer  is  more confining at greater distances,
the relative  effects  are quite  similar  between the two  cases  because
horizontal  and longitudinal  dispersion are playing a larger role at the
greater distance.   See Table  124.
                                  141

-------
                              Table  131.

                  The Effect of a Very Thick Aquifer
                         at a 1000 Meter Well.
 S18-1000,  1000 M BASE CASE BUT WITH AQUIFER THICKNESS = 560 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3709E+02
1.0423E+02
l.OOOOE+04
6.3796E+03
l.OOOOE+04
l.OOOOE+04
1.7503E+00
4.5136E+02
2.7927E+01
l.OOOOE+04
3.1791E+03
1.1857E+00
l.OOOOE+04
3.3130E+03
l.OOOOE+04
2.2927E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
7.6686E+03
l.OOOOE+04
l.OOOOE+04
2.0954E+01
5.4921E+03
1.8069E+02
l.OOOOE+04
l.OOOOE+04
1.1857E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
2.7405E+01
% DIFFERENCE
4117.8 %
9494.2 %
0.0 %
20.2 %
0.0 %
0.0 %
1097.2 %
1116.8 %
547.0 %
0.0 %
214.6 %
0.0 %
0.0 %
201.8 %
0.0 %
1095.3 %
     This case is  similar  to  S18-500  but  at  a greater travel  distance.
Therefore, the effects are  the  same  but more pronounced since there is
greater distance  over which vertical dispersion can  dilute  the  plume.
See Table 122.
                                  142

-------
                              Table  132.

                     The Effect of a Thick Aquifer
                         at a 1000 Meter Well.
 S19-1000, AQUIFER THICKNESS 78.6 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-02
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
l.OOE+04
l.OOE+04
l.OOE+04
7.64E+03
l.OOE+04
l.OOE+04
9.18E+00
2.36E+03
1.33E+02
l.OOE+04
8.73E+03
1.19E+00
l.OOE+04
l.OOE+04
l.OOE+04
1.20E+01
% DIFFERENCE
4115.9 %
9496.9 %
0.0 %
20.2 %
0.0 %
0.0 %
424.7 %
423.5 %
375.7 %
0.0 %
174.7 %
0.0 %
0.0 %
201.8 %
0.0 %
423.8 %
     This case  is  similar to S19-500 but at  a  longer travel  distance.
The  effects  are   the  same  but  of  greater  magnitude  since  aquifer
thickness is more confining at greater flow distances.  See Table 122.
                                  143

-------
                              Table 133.

                     The Effect of a Thin Aquifer
                         at a 1000 Meter Well.
 S20-1000,  AQUIFER THICKNESS 5 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-02
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
4.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
6.83E+01
3.11E+01
l.OOE+04
2.60E+03
l.OOE+04
l.OOE+04
5.84E-01
1.51E+02
9.30E+00
l.OOE+04
1.24E+03
1.19E+00
5.21E+03
1.13E+03
5.77E+03
7.65E-01
-71.2 %
-70.2 %
0.0 %
-59.0 %
0.0 %
0.0 %
-66.6 %
-66.6 %
-66.8 %
0.0 %
-61.1 %
0.0 %
-47.9 %
-66.0 %
-42.3 %
-66.6 %
     This case  is similar  to  S20-500 with  a longer travel  distance.
Since  longer   travel   distances  would  normally   lead   to   vertical
dispersion  to  greater  depths,   the  thin aquifer  dimensions  are  more
confining for this case.   THerefore,  the impact  of the  thinner aquifer
is more pronounced.  See Table 124.
                                  144

-------
                              Table 134.

                 The Effect of a Lower Oxidation  State
                          at a 50 Meter Well.
 S21-50,  EH 150 MV,  PH 6.0,  DIST = 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY %
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
6.1599E+00
2.7423E+00
l.OOOOE+04
2.3936E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8846E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1277E+01
8.4160E-01
DIFFERENCE
0.3 %
-0.2 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.2 %
0.0 %
0.0 %
0.0 %
0.6 %
0.0 %
     This case illustrates the effect  of  a  lower  state  of oxidation  in
the groundwater.   It  would  be  expected  to change results  for  metals
affected by groundwater geochemistry.   In this  case,  the  change  had  no
significant  impact  on  solubility  levels   and   so  would  not  change
allowable sludge levels.
                                  145

-------
                              Table  135.

                 The Effect of Reducing Conditions and
                    Elevated pH at a 50 Meter Well.
 S22-50,  EH -200 MV,  PH 7.0, DIST = 50 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
5.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
l.OOOOE+04
2.7423E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8846E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1277E+01
8.4160E-01
% DIFFERENCE
162777.1 %
-0.2 %
0.0 %
4077.1 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.2 %
0.0 %
0.0 %
0.0 %
0.6 %
0.0 %
     This  case   illustrates  the  effect   of   encountering  reducing
conditions and  a  higher pH  in the  groundwater.   The  solubility of two
chemicals  was  greatly   effected.     Both   Arsenic   and  Lead  be' .me
sufficiently insoluble  to control  concentrations  below risk levels and
allow sludge limits to go to the maximum level of 10,000 mg/kg.
                                  146

-------
                              Table 136.

                   The Effect of a Lower Oxidation State
                         at a 150 Meter Well.
 S21  150,  EH 150 MV,  PH 6.0,  DIST 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY %
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
2.8004E+01
9.7000E+00
l.OOOOE+04
5.1058E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3938E+01
l.OOOOE+04
1.7201E+01
7.0109E-02
4.9262E+01
1.4711E+03
5.1291E+01
1.1132E+00
DIFFERENCE
18.2 %
2.5 %
0.0 %
2.1 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
0.1 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
     This case is similar  to  S21-50  at  a  greater travel  distance.   The
apparent  effect  on  Arsenic  is  likely  to  be  a  result  of the  back
calculations  rather  than  an  impact  since Arsenic  solubility is  not
effected in this Eh range.  See Table 134.
                                  147

-------
                              Table 137.

                 The Effect of Reducing Conditions  and
                    Elevated pH at a 150 Meter Well.

 S22-150,  EH -200 MV,  PH 7.0,  DIST = 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.020.0E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
l.OOOOE+04
9.6358E+00
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3945E+01
l.OOOOE+04
1.7201E+01
7.0109E-02
4.9262E+01
1.4711E+03
5.1291E+01
1.1132E+00
% DIFFERENCE
42108.3 %
1.9 %
0.0 %
1900.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.1 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
     This case is the  same  as  S22-50  at a longer travel  distance.
results are the same as well.  See Table 135.
The
                                  148

-------
                              Table 138.

                 The Effect of a Lower Oxidation State
                          at  a 500 Meter Well.

 S21-500,  500 M BASE CASE BUT EH = 150 MV,  PH = 6.0
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY %
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
1.1048E+02
4.6636E+01
l.OOOOE+04
2.4780E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7658E+01
l.OOOOE+04
2.3053E+02
3.9816E-01
8.7968E+02
2.1289E+03
1.3018E+03
1.5178E+00
DIFFERENCE
4.4 %
-0.1 %
0.0 %
18.2 %
0.0 %
0.0 %
0.0 %
0.0 %
0.1 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
     This  case  is analogous  to S21-500  at  a longer  travel  distance.
The apparent effect on  Lead  is  a result of poor resolution in the back
calculation to allowable sludge levels.  See Table 134.
                                  149

-------
                              Table  139.

                 The Effect of Reducing Conditions and
                    Elevated  pH  at  a  500 Meter Well.

 S22-500,  500 M BASE CASE BUT EH = -200 MV, PH = 7.0
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3.061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
l.OOOOE+04
4.6952E+01
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7658E+01
l.OOOOE+04
2.3053E+02
3.9816E-01
8.7968E+02
2.1289E+03
1.3018E+03
1.5178E+00
9348.2 %
0.6 %
0.0 %
376.9 %
0.0 %
0.0 %
0.0 %
0.0 %
0.1 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
     This case is the  same  as  S22-50 at a longer travel distance,
Table 135.
See
                                  150

-------
                              Table 140.

                 The Effect of a Lower Oxidation  State
                         at a 1000 Meter Well.
 S21  1000,  EH 150 MV,  PH 6.0
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-02
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY %
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
2.46E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.53E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
DIFFERENCE
3.8 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.3 %
0.2 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
     This case  is  the  same  as  S21-50 at a longer travel distance.
Table 134.
See
                                   151

-------
                               Table  141.

                 The Effect of Reducing Conditions and
                   Elevated pH at a 1000 Meter Well.
 S22-1000, EH -200 MV, PH 7.0
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-02
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
l.OOE+04
1.04E+02
l.OOE+04
l.OOE+04
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.79E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
4115.9 %
0.2 %
0.0 %
57.4 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.3 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
0.0 %
     This case  is  the same as  S22-50  at  longer travel  distances.   See
Table  135.    The  effects  on  Lead  are  reduced  because  the  maximum
allowable sludge level reached  the arbitrary cutoff of 10,000 mg/kg.
                                  152

-------
                              Table  142.

                The Effect of Increased Sludge Moisture
                      Content at a 50 Meter Well.

 S23-50,  SLUDGE MOISTURE CONTENT 0.95,  DIST = 50  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E-I-02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
3.4420E+01
1.2971E+01
l.OOOOE+04
9.7563E+02
l.OOOOE+04
l.OOOOE+04
6.7480E-01
2.2590E+02
9.1168E+00
l.OOOOE+04
5.4152E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1277E+01
8.8218E-01
460.6 %
372.2 %
0.0 %
307.5 %
0.0 %
0.0 %
4.8 %
0.0 %
16.4 %
0.0 %
10.7 %
0.0 %
0.0 %
0.0 %
0.6 %
4.8 %
     This  case  illustrates  the  effect  of  a  higher  initial  moisture
content  in  the sludge.    The  greater moisture  level  means  there  are
correspondingly fewer  solids  in  a  given  volume  of  sludge  (e.g.  the
landfill) and, therefore, a smaller total inventory of contaminant.   As
a consequence,  the pulse width  (release time)  is  reduced  relative  to
the travel  time,   this  allows  for  greater  effects from  dispersion  in
chemicals where the release time  is small  compared to the travel  time.
The effects are noted on four contaminants:  Arsenic,  Cadmium, Lead  and
BEHP.    The effects  on  BEHP  are negative  because the  reduced  sludge
concentrations reduces  the vapor release  rate  and BEHP  risk  is  vapor
controlled.
                                  153

-------
                              Table  143.

                   The  Effect of Decreased Moisture
                      Content at a 50 Meter Well.

 S24-50,  SLUDGE MOISTURE CONTENT 0.60, HEL = l.OE-04,  DIST = 50  M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3'OOOE+OO
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
6.1396E+00
2.7471E+00
l.OOOOE+04
2.3940E+02
l.OOOOE+04
l.OOOOE+04
6.4376E-01
2.2590E+02
1.0911E+01
l.OOOOE+04
4.8922E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1159E+01
8.4160E-01
3.0689E+00
1.3720E+00
l.OOOOE+04
1.1961E+02
l.OOOOE+04
l.OOOOE+04
6.4267E-01
2.2590E+02
1.0913E+01
l.OOOOE+04
4.8880E+00
2.1959E-02
1.4286E+01
9.3867E+02
2.1277E+01
8.4177E-01
-50.0 %
-50.1 %
0.0 %
-50.0 %
0.0 %
0.0 %
-0.2 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
0.0 %
0.0 %
0.6 %
0.0 %
     This case  is  the opposite  of S23-50.   The  pulse  widths (release
times)  are  increased  in  this  case  and,  therefore, allowable  sludge
levels are reduced for Arsenic, Cadmium, and Lead.  See Table 142.  The
effects on BEHP  are  negligible  because the  allowable levels are driven
by vapors and  the  controlling concentration was  reached  near the base
case moisture content.
                                  154

-------
                              Table  144.

            The Effect of Increased Sludge Moisture  Content
                          at  a 150  Meter Well.

 S23-150,  SLUDGE MOISTURE CONTENT 0.95, DIST 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
1.0673E+02
4.0770E+01
l.OOOOE+04
2.0758E+03
l.OOOOE+04
l.OOOOE+04
8.4987E-01
2.5007E+02
1.6912E+01
l.OOOOE+04
1.7193E+01
7.0109E-02
4.8020E+01
1.4711E+03
5.1291E+01
1.1139E+00
350.5 %
331.0 %
0.0 %
315.2 %
0.0 %
0.0 %
0.0 %
0.0 %
21.2 %
0.0 %
0.0 %
0.0 %
-2.5 %
0.0 %
-0.1 %
0.1 %
     This case is the same as S23-50 at a greater travel  distance.   See
Table  142.   The  increase in  BEHP  allowable levels reflects  a  change
over from vapor driven to groundwater transport driven mechanisms.
                                  155

-------
                              Table 145.

               The Effect of Decreased Sludge Moisture
                     Content at  a  150 Meter Well.

 S24-150,  SLUDGE MOISTURE CONTENT 0.60,  DIST 150 M
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.3692E+01
9.4591E+00
l.OOOOE+04
5.0000E+02
l.OOOOE+04
l.OOOOE+04
8.4983E-01
2.5007E+02
1.3949E+01
l.OOOOE+04
1.7187E+01
7.0109E-02
4.9262E+01
1.4718E+03
5.1357E+01
1.1132E+00
1.2000E+01
4.8447E+00
l.OOOOE+04
2.5378E+02
l.OOOOE+04
l.OOOOE+04
8.5009E-01
2.5007E+02
1.3940E+01
l.OOOOE+04
1.1809E+01
7.0109E-02
4.8427E+01
1.4711E+03
5.1291E+01
9.3116E-01
-49.3 %
-48.8 %
0.0 %
-49.2 %
0.0 %
0.0 %
0.0 %
0.0 %
-0.1 %
0.0 %
-31.3 %
0.0 %
-1.7 %
0.0 %
-0.1 %
-16.4 %
     This case is the  same  as  S24-50 at a longer travel distance.   See
Table 143.  Note that at 150 meters, the travel time is long enough for
reduced pulse width to effect allowable DDT sludge concentrations.
                                   156

-------
                              Table 146.

               The Effect of  Increased Sludge Moisture
                     Content  at  a 500 Meter Well.

 S23-500,  500 M BASE  CASE BUT WITH SLUDGE MOISTURE CONTENT =  0.95
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
4.3573E+02
1.9038E+02
l.OOOOE+04
7.8150E+03
l.OOOOE+04
l.OOOOE+04
1.0952E+00
2.9889E+02
5.0188E+01
l.OOOOE+04
2.3043E+02
3.9816E-01
8.8110E+02
2.1289E+03
1.0341E+03
1.4551E+00
311.7 %
307.8 %
0.0 %
272.7 %
0.0 %
0.0 %
-5.5 %
0.0 %
184.5 %
0.0 %
-0.1 %
0.0 %
0.2 %
0.0 %
-20.7 %
-4.1 %
     This case  is  the  same as S23-50 at a longer travel distance.
Table 142.
See
                                   157

-------
                              Table 147.

                The Effect of Decreased Sludge Moisture
                     Content at a 500  Meter Well.

 S24-500,  500 M BASE CASE BUT WITH SLUDGE MOISTURE CONTENT =  0.60
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
5.0000E-02
l.OOOOE-02
1.3000E+00
5.0000E-02
2.0000E-03
1.7500E+00
5.0000E-03
3.0000E-04
2.4800E-01
2.1000E-03
1.0200E-02
l.OOOOE-04
4.0000E-03
4.5400E-04
5.0000E-03
5.0000E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
1.0584E+02
4.6687E+01
l.OOOOE+04
2.0969E+03
l.OOOOE+04
l.OOOOE+04
1.1587E+00
2.9889E+02
1.7638E+01
l.OOOOE+04
2.3061E+02
3.9816E-01
8.7968E+02
2.1299E+03
1.3035E+03
1.5178E+00
5.2839E+01
2.3320E+01
l.OOOOE+04
1.2394E+03
l.OOOOE+04
l.OOOOE+04
1.1590E+00
2.9889E+02
1.9167E+01
l.OOOOE+04
2.3028E+02
3.9816E-01
8.8049E+02
2.1289E+03
1.3018E+03
1.5185E+00
-50.1 %
-50.1 %
0.0 %
-40.9 %
0.0 %
0.0 %
0.0 %
0.0 %
8.7 %
0.0 %
-0.1 %
0.0 %
0.1 %
0.0 %
-0.1 %
0.0 %
     This case  is  the  same  as  S24-50 at a longer travel distance.
Table 143.
See
                                  158

-------
                              Table  148.

               The  Effect of  Increased Sludge Moisture
                     Content at a 1000 Meter Well.
 S23-1000, SLUDGE MOISTURE CONTENT 0.95
CHEMICAL
ARSENIC
CADMIUM
COPPER
LEAD
MERCURY
NICKEL
BENZENE
B(A)P
BEHP
CHLORDANE
DDT
DMN
LINDANE
PCB
TCE
TOXAPHENE
HEALTH
STANDARD
(MG/L)
4.94E-02
l.OOE-02
2.40E-01
4.90E-02
2.29E-04
5.13E-01
4.99E-03
3.01E-04
2.48E-01
O.OOE+00
8.02E-03
O.OOE+00
2.56E-03
4.41E-04
2.89E-03
5.00E-03
ALLOWABLE SLUDGE
CONCENTRATION (MG/KG)
BASELINE SENSITIVITY % DIFFERENCE
2.37E+02
1.04E+02
l.OOE+04
6.35E+03
l.OOE+04
l.OOE+04
1.75E+00
4.51E+02
2.80E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.29E+00
9.57E+02
4.15E+02
l.OOE+04
l.OOE+04
l.OOE+04
l.OOE+04
1.71E+00
4.53E+02
7.71E+01
l.OOE+04
3.18E+03
1.19E+00
l.OOE+04
3.31E+03
l.OOE+04
2.36E+00
303.2 %
298.5 %
0.0 %
57.4 %
0.0 %
0.0 %
-2.2 %
0.3 %
175.5 %
0.0 %
0.1 %
0.0 %
0.0 %
0.0 %
0.0 %
3.0 %
     This case  is the  same  as  S23-50 at a longer travel distance.
Tables 142 and  144.
See
                                  159

-------
              APPENDIX C
Approved Methods for Site-Specific Parameters

-------
                       APPROVED METHODS  FOR
                     SITE-SPECIFIC  PARAMETERS


     Site-specific determinations of the maximum allowable
pollutant concentrations in the sludge may be made under certain
conditions (See Chapter 5.)  Before a site-specific determination
can be made, however, the basic information for each parameter
must be obtained.  Where standard methods exist, they"must be
used in order to validate the site-specific inputs to the
SLUDGEMAN computer model.   This appendix catalogs the acceptable
standard methods or other sources for these parameters.

EH

     The pH of^the groundwater may be measured by using  Standard
Method D 1293-78, Standard Test Methods for pH of Water.   [ASTM,
1982]  Either Method A or Method B is acceptable for this
regulation since the input will be expressed to the nearest pH
unit (6 or 7) .

Eh

     Standard Method D 1498-76, Standard Practice for oxidation-
reduction potential of water is the acceptable method for Eh.
The value measured is then compared to the allowable inputs and
the closest value (-200 mv, +150 mv,  or +500 mv) is chosen as the
input.  [ASTM,  1982]

Soil Type

     The soil type parameter is more properly defined as the soil
texture as classified by the Soil Conservation Service.   The soil
texture may be determined by the Particle Fractionization and
Particle-size Analysis in Methods of Soil Analysis. [Black, 1982]
From this analysis the percent clay,  sand, and silt may  be
determined.  This information is used to determine the soil
texture by locating the intersection of the percentages  on the
Soil Conservation Service soil textural classification chart.
[SCS, 1951]

Depth to Groundwater

     The depth to groundwater may be measured in any
representative well.  Measurements may need to be taken  monthly
for areas with greatly varying water tables.  In this case, the
smallest depth to groundwater  (the highest water table)  is the
value which is input into the computer model.
                               C-l

-------
     Net Recharge is a parameter not easily measured in the
field.  For the purposes of this regulation, an estimate can be
made from precipatat ion  (either from area records or
estrapolation) and evapotranspirat ion values.  Evapotranspiration
balues may be estimated  from measurements of pan evaporation.
The evapotranspirat ion value is subtracted from the precipatat ion
value to arrive at the estimated recharge value.  If the rainfall
is seasonal, then monthly measurements should be made and
averaged over the year.
     The Kd value for metals may be estimated using the method of
Gerritse et al.  [1982].  Gerritse made estimates of Kds in sand
and sandy  loam soils.  The same methodology may be used for other
soil textures.

     For organics the Kd may be estimated from the Koc .  The Koc
is estimated using  the method  in Lymari et . al. [1982]  The
fraction of organic  carbon  ( f oc ) is measured using the Walkley-
Black method.  [Black, 1982]  The Kd is then estimated  from the
equation:
                Kd   "   Koc   x   f
oc
                                C-2

-------
                            REFERENCES

ASTM (American Society tor Testing and Materials.  1982.  Annual
Book of ASTM Standards. Part 31 - Water.  Easton, FID.

Black,  C.A., 1982.  Methods of Soil Analysis.  Am. Soc.  of
Agronomy Monograph #9.

Gerritse, R.G., R. Vriesema, J.W. Dalenberg, and H.P.  DeRoos.
1982. Effect of Sewage Sludge on Trace Element Mobility in Soils
J. Environ. Qual. 2:359-363.

Lyman,  W.J. 1982. Adsorption Coefficients for Soils and
Sediments. Chapter 4.  In: Handbook of Chemical Property
Estimation Methods. McGraw-Hill Book  Co., New York, NY.

Soil Conservation Service,  1951.  Soil survey manual; USDA.
                                C-3

-------
                                REFERENCES
Algermission, S.T. and D.M. Perkins.  1976.  A probabilistic estimate of
    maximum acceleration in rock in the contiguous United States.   U.S.
    Geological Survey Open-File Report 76-416.

Algermission, S.T. and D.M. Perkins.  1982.  Probabilistic estimates of
    maximum acceleration and velocity in rock in the contiguous United States.
    U.S. Geological Survey Open-File Report 82-1033.

American Public Health Association.  1971.  Standard methods for the
    examination of water and wastewater.  13th ed.

Baldwin. M.F.  1985.  Establishing a wetland protection system under EPA's
    wetland protection and review authorities.  Great Falls, VA:  Baldwin
    Associates.

Earth, E.F., J.N. English, B.V. Salotto, B.N. Jackson andM.B. Ettinger.
    1965.  Field  survey of four municipal wastewater treatment plants
    receiving metallic wastes.  J. Wat. Pollut. Contr. Fed. 37(8).

Battelle Pacific  Northwest Laboratories.  1976.  Toxicological criteria for
    defining hazardous wastes.  Minnesota Pollution Control Agency.

Black, C.A., ed.  1982.  Rapid dichromate oxidation technique  (Walkley-Black
    method).  In:  Methods of soil analysis, part 2:  Chemical and
    microbiological properties, 565.  American Society of Agronomy Monograph
    No. 9.

Blokpoel, H.  1976.  Bird hazards to aircraft.  Buffalo, NY:  Books Canada,
    Inc.

Bolt, B.A.  1978.  Earthquakes:  a primer.  San Francisco, CA:  W.H. Freeman
    and Company.

Bond, R.G. and C.P. Straub, eds.  1974.  Wastewater -- treatment and disposal.
    CRC handbook  of environmental control.  Vol. IV.

California Division of Mines and Geology.  1975.  Guidelines for evaluating
    the hazard of surface fault rupture.  CDMG Note Number 49.  Sacramento,
    CA:  Department of Conservation, State of California.

Dawson, G.W., C.J. English and S.E. Petty.  1980.  Physical chemical
    properties of hazardous waste constituents.  Washington, DC:  EPA
    Office of Solid Waste.

DOI (U.S. Department of Interior).  1974.  Earth manual:  a water
    resources technical publication.  2nd ed.  Washington, DC:  DOI,    Water
    and Power Resources Service.


                                      8-1

-------
DOI (U.S.  Department of Interior).  1978.  A study of the ecosystem of
    Tompkins County Airport,  Ithaca, New York with recommendations to
    alleviate bird hazards to aircraft operations.  Newton Corner, MA:  DOI,
    Fish and Wildlife Service.

Eckenfelder, W.W.,  Jr., and Santhanam, C.J.  1981.  Sludge treatment.  New
    York:   Marcel Dekker.

EPA (U.S.  Environmental Protection Agency).  1977a.  Letter of March 1, 1977
    from S.C. James to T.V. DeGreare, Jr. on international trip report.
    Washington, DC:  EPA.

EPA (U.S.  Environmental Protection Agency).  1977b.  Environmental assessment
    of subsurface disposal of municipal wastewater sludge.  Interim report.
    Report No. EPA-530/SW-547.   Cincinnati, OH:  Municipal Environmental
    Research Laboratory (MERL).

EPA (U.S.  Environmental Protection Agency).  1978.  Municipal sludge landfill
    Process design manual.  Report No. EPA-625/1-78-010/SW-705.   Washington,
    DC:  Office of Solid Waste.

EPA (U.S.  Environmental Protection Agency).  1979.  Background document:
    disease.  Criteria for Classification of Solid Waste Disposal Facilities
    (40 CFR Part 257).  Subtitle D of the-Resource Conservation and Recovery
    Act (RCRA).  Washington,  DC:  Office of Solid Waste.

EPA (U.S.  Environmental Protection  Agency).  1980.  Classifying solid waste
    disposal facilities (SW-828).   Washington, DC:  Office of Solid Waste.

EPA (U.S.  Environmental Protection  Agency).  1982.  Fate of priority
    pollutants in publicly-owned treatment works.  Vol. 1.  Final report.
    Report No. EPA 440/1-82/303.  Washington, DC:  Effluent Guidelines
    Division.

EPA (U.S.  Environmental Protection  Agency).  1983.  Memorandum of June 27,
    1983 from Alexander Wolfe to Penelope Hansen.  Washington, DC:  EPA.

EPA (U.S.  Environmental Protection Agency).  1984.  Environmental regulations
    and technology:  Use and disposal of municipal wastewater sludge.  Report
    No. EPA Report No. 625/10-84-003.  Prepared by Eastern Research Group,  Inc.
    for EPA Interagency Sludge Task Force.

EPA (U.S.  Environmental Protection Agency).  1985a.  Technical support for
    development of guidelines on hydrogeologic criterion for hazardous waste
    management facility location.   Draft.

EPA (U.S.  Environmental Protection Agency).  1985b.  DRASTIC:  A standardized
    system for evaluating ground water pollution potential using hydrogeologic
    settings.  Report No. EPA-600/2-85/018.  Ada, OK:  EPA.
                                      8-2

-------
EPA (U.S. Environmental Protection Agency).  1986a.  Development of risk
    assessment methodology for municipal sludge landfilling.  ECAO-CIN-485.
    Cincinnati, OH:  EPA Environmental Criteria and Assessment Office (ECAO).

EPA (U.S. Environmental Protection Agency).  1986b.  EPA strategy for wetlands
    protection under Section 404, Clean Water Act.  Draft.  Washington  DC:
    EPA.

EPA (U.S. Environmental Protection Agency).  1986c.  Hazardous waste
    management system land disposal restrictions regulation.  51 FR 1602,
    January 14.

EPA (U.S. Environmental Protection Agency).  1987a.  Integrated risk
    information system supportive documentation.  In:  Reference dose (RfD)
    description and use in health risk assessment.  Report No. EPA-600/8-
    86/032a. Washington, DC:  Office of Health and Environmental Assessment.

EPA (U.S. Environmental Protection Agency).  1987b.  Communication of May 7,
    1987 between G. Dorian and V.W. Lambou.  Subject:  Estimate of the area of
    wetlands and deepwater habitats in the United States.  Washington, DC:
    EPA.

EPA (U.S. Environmental Protection Agency)   1988.  Integrated Risk
    Information System  (IRIS).  August 30, 1988.  Washington, DC:  EPA.

EPA (U.S. Environmental Protection Agency).  1988a.  Location restrictions
    (Subpart B):  Criteria for municipal solid waste landfills (40 CFR Part
    258).  Subtitle D of the Resource Conservation and Recovery Act (RCRA)
    Washington, DC:  Office of Solid Waste.

EPA (U.S  Environmental Protection Agency)   1988b.  Operating criteria
    (Subpart C):  Criteria for municipal solid waste landfills (40 CFR Part
    258).  Subtitle D of the Resource Conservation and Recovery Act (RCRA)
    Washington, DC:  Office of Solid Waste.

EPA (U.S. Environmental Protection Agency).  1988c.  Case studies on ground-
    water and  surface water contamination from municipal solid waste
    landfills: Criteria for municipal solid waste landfills  (40 CFR Part 258)
    Subtitle D of the Resource Conservation and Recovery Act  (RCRA).
    Washington, DC:  Office of Solid Waste.

EPA (U.S. Environmental Protection Agency).  1989.  Technical support document
    for pathogens/vector attraction reduction in sewage sludge.  Draft.
    Washington, DC:  Office of Water Regulations and Standards.

ESE (Environmental Science and Engineering).  1985.  Exposure to airborne
    contaminants released from land disposal facilities -- a proposed
    methodology.  Environmental Protection Agency.

Executive Order 11988.  Floodplain management.  May 24, 1977, as amended.
    Reprinted by the Bureau of National Affairs, Washington, DC.
                                       3-3

-------
Executive Order 11990.   1977 Protection of wetlands.   Reprinted by the Bureau
    of National Affairs,  Washington,  DC.

(FAA) Federal Aviation Administration.   1974.   FAA guidance concerning
    sanitary landfills on or near airports,  Oct.  16,  1974.  Order 5200.5.
    Washington, DC:   U.S. Department of Transportation, FAA.

(FAA) Federal Aviation Administration.   1978.   Aircraft bird strikes summary
    and analysis.  Washington,  DC:   U.S.  Department of Transportation, FAa.

Felmy, A.R.,  D.C. Girvin and E.A. Genne.   1984.  MINTEQ -- a computer program
    for calculating aqueous geochemical equilibrium.   Report No. EPA-600/3-84-
    032.  Athens, GA:  Environmental Research Lab.

Freeze, R.A.  and J.A. Cherry.  1979.   Groundwater.  Englewood Cliffs, NJ:
    Prentice-Hall.

GCA Corporation.  1986a.   Evaluation of location-based bans and closures of
    Subtitle D facilities.  Draft report.   Contract No. 68-01-6871.
    Washington, DC:   Environmental Protection Agency.

GCA Corporation.  1986b.   Review of federal and state regulations and other
    information on disposal of solid wastes in wetlands.  Contract No. 68-01-
    6871.  Washington, DC:  Environmental Protection Agency.

GCA Corporation.  1986c.   Regulatory development plan supplemental
    information.  Draft final report.  Volume II, Appendix 11.2, Hazardous
    waste facility location standards for protection from subsurface gas
    migration, and Appendix  11.4,  Controls on location of RCRA hazardous
    waste management facilities in consideration of hazardous air emissions.
    Contract No. 68-01-6871.  Washington,  DC:   Environmental Protection
    Agency.

Gerritse, R.G., R. Vriesema, J.W. Dalenberg and H.P.  DeRoos.  1982.  Effect of
    sewage sludge on trace element mobility in soils.  J. Environ. Qual.
    2:359-363.

Guven, O.F.,  F.J. Molz,  and J.G. Melville.  1984.  An analysis of dispersion
    in a stratified aquifer.  Wat.  Resour. Res.  20:1337-1354

Hall, D.G.M., A.J. Reeve, A.J.  Thomasson and V.F. Wright.  1977.  Water
    retention, porosity,  and density of field soils.   Soil survey technical
    monograph 9.  Harpenden, England:  Rothamsted Experimental Station.

Hen, John D.   1985.   Significance of properties and constituents reported in
    water analysis.   In:   Study and interpretation of the chemical
    characteristics of natural water.  3rd edition.  Water-supply paper  1473.
    Reston, VA:  USGS Department of Interior.
Hwang, S.T.  1982.  Toxic emissions from land disposal facilities.
    Environ. Prog.  l(l):46-52.
                                      3-4

-------
Hynes-Griffin, M.A. and A.G. Franklin.  1984.  Rationalizing the seismic
    coefficient method.  Miscellaneous paper GL-84-13.  Washington, DC:
    Waterways Experiment Station, U.S. Army Corps of Engineers, Department of
    the Army.

Kleopfer, Robert D., D.M. Easley, B.B. Haas, T.T. Deihl, B. Jackson and C.J.
    Wrey.  1985.  Anaerobic degradation of trichlorethylene in soil.  Environ.
    Sci. Tech.  (3)19:277.

Kollig, H.P.  Personal communication.  Athens, GA:  EPA Environmental
    Research Laboratory.

Lambe, T.W. and R.V. Whitman.  1969.  Soil mechanics.  New York:  John Wiley
    and Sons, Inc.

Legget, R.F. and P.P. Karrow.  1983.  Handbook of geology in civil
    engineering.  New York:  McGraw-Hill, Inc.

Lutton, R.J.  1082.  Evaluating cover systems for solid and hazardous waste
    (SW-867).  Interagency agreement No. EPA-IAG-D7-01097.   Washington, DC:
    Environmental Protection Agency.

Lyman, W.J., W.S. Reehl and D.H. Rosenblatt.  1982.  Adsorption coefficients
    for soils and sediments.  In:  Handbook of chemical property estimation
    methods*  Chapter 4.  New York:  McGraw-Hill, Inc.

Mackay, D. and W.Y. Shiu.  1981.  Critical review of Henry's law constants for
    chemicals of environmental interest.  J. Phys. Chem. Ref. Data.
    10(4):1175-1199.

Mackay, D.M., P.V. Roberts and J.A. Cherry.  1985.  Transport of organic
    contaminants in groundwater.  Environ. Sci. Tech.  19:384-392.

McAneny, C.C. et al.  1985.  Covers for uncontrolled hazardous waste sites.
    Report No. EPA 540/2-85/002.  Washington, DC:  Environmental Protection
    Agency.

Mahey, et al.  1982.  Aquatic fate process data for organic priority
    pollutants.  Report No. EPA 440/4-81-014.  Washington,  DC:  Environmental
    Protection Agency.

Marshall, T.J. and J.W. Holmes.  1979.  Soil Physics.  Cambridge, England:
    Cambridge University Press.

Midwest Research Institute  (MRI).  1984.  Floods, floodplains, and a screening
    methodology for wastes on floodplains.  Draft report.  Washington, DC:
    Environmental Protection Agency.

MITRE Corporation.  1980.  Guidance for siting hazardous waste management
    facilities in a 100-year floodplain.  Working paper.  December 2.  McLean,
    VA:  MITRE Corporation.
                                      8-5

-------
Noble, G.  1976.  Sanitary landfill design handbook.  Westport, CT:  Technomic
    Publishing Co.,  Inc.

OTA (Office of Technology Assessment).   1984.   Wetlands:  their use and
    regulation.  OTA-0-206.  Washington, DC:   OTA.

Prakash, S.  1981.  Soil dynamics.  New York:   McGraw-Hill,  Inc.

Raghu, K. and I.C. MacRae.  1966.  Biodegradation of the gamma-isomer
    of benzene hexachloride in submerged soils.  Sci. 154:263.

Shafer, J.M., P.L. Oberlander and R.L.  Skaggs.   1984.  Mitigative techniques
    and analysis of generic site conditions for ground-water contamination
    associated with sewer accidents.  Nureg/CR-3681, PNL-5072.

SCS Engineers.  1985.  Landfill gas update.  Summaries of technical reports.
    Reston, VA:  SCS Engineers.

Solman, V.E.F.  1973.  Influence of garbage dumps near airports on bird hazard
    to aircraft.  Paper presented at the National Conference on Urban
    Engineering Terrain Problems, Montreal, Quebec.

Southerland, Betsy.   1987.  Personal Communication.   Washington, DC:  EPA
    Office of Water.

Terzaghi, K. and R.B. Peck.  1967.  Soil mechanics in engineering practice.
    New York:  John Wiley and Sons,-Inc.

Todd, O.K.  1980.  Groundwater hydrology.  2nd ed.  New York:  John
    Wiley and Sons.

Tucker, W.A. and Preston, A.L.  1984.  Procedures for estimating atmospheric
    deposition properties of organic chemicals.  Wat., Air,  Soil Pollut.
    12:247-260.

Ultrasystems, Inc.  1977.  An analysis of avian use of the Miliken sanitary
    landfill.  Irvine, CA:  Ultrasystems, Inc.

USGS  (U.S. Geological Survey).  1981.  Facing geologic and hydrologic
    hazards.  Professional Paper 1240-B.  Washington, DC:  USGS.

Vail  (Raymond) and Associates.  1979.  State of Colorado investigation of
    methane gas problems at high priority waste disposal sites.   Wheat Ridge,
    CO:  Vail and Associates.

Van Genuchten, M. 1985.  Convective-dispersive transport of solutes
    involved in sequential first-order decay reactions.  Comput. Geosci.
    11(2):129-147.

Verschueren, K., ed.  1983.  Handbook of environmental data on organic
    chemicals.  2nd ed.  New York:  Van Nostrand Reinhold Co.
                                      8-6

-------
Viessman, H.W.,  J.W. Knapp, G.L. Lewis and T.H. Harbaugh.  1977.
    Introduction to hydrology.  New York:  Harper and Row.

Weiss, S.  1974.  Sanitary landfill technology.  Park Ridge, NJ:  Noyes Data
    Corporation.

Winterkorn, H.F. and F. Hsai-Yang, eds.   1975.  Foundation engineering
    handbook.  New York:  Van Nostrand Reinhold Company.

Wolf, N.L., R.G. Zepp, D.F. Paris, G.L.  Baughman and R.C. Hollis.  1977
    Methoxychalor and DDT deregulation in water:  rates and products.
    Environ. Sci. Tech. 11:1077.

Yeh, G.T.  1981.  AT123D:  Analytical transient one-, two-, and three-
    dimensional simulation of waste transport in the aquifer system.
    Environmental Sciences Division Publication No. 1439.  Oak Ridge, TN:  Oak
    Ridge National Laboratory.

-------