&EFA
United States
Environmental Protection
Agency
Office ot Water
Regulations and Standards
Washington, DC 20460
Water
June, 1985
Environmental Profiles
and Hazard Indices
for Constituents
of Municipal Sludge:
Benzene
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PREFACE
This document is one of a series of preliminary assessments dealing
with chemicals of potential concern in municipal sewage sludge. The
purpose of these documents is to: (a) summarize the available data for
the constituents of potential concern, (b) identify the key environ-
mental pathways for each constituent related to a reuse and disposal
option (based on hazard indices), and (c) evaluate the conditions under
which such a pollutant may pose a hazard. Each document provides a sci-
entific basis for making an initial determination of whether a pollu-
tant, at levels currently observed in sludges, poses a likely hazard to
human health or the environment when sludge is disposed of by any of
several methods. These methods include landspreading on food chain or
nonfood chain crops, distribution and marketing programs, landfilling,
incineration and ocean disposal.
•
These documents are intended to serve as a rapid screening tool to
narrow an initial list of pollutants to those of concern. If a signifi-
cant hazard is indicated by this preliminary analysis, a more detailed
assessment will be undertaken to better quantify the risk from this
chemical and to derive criteria if warranted. If a hazard is shown to
be unlikely, no further assessment will be conducted at this time; how-
ever, a reassessment will be conducted after initial regulations are
finalized. In no case, however, will criteria be derived solely on the
basis of information presented in this document.
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TABLE OF CONTENTS
Page
PREFACE . . . . . . . . . , . . . . .
1 • INTRODUCTION . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . 1—1
2. PRELIMINARY CONCLUSIONS FOR BENZENE IN MUNICIPAL SEWAGE
SLUDGE... ,•,•• 2—1
Landspreading and Distribution—and—Marketing 2—1
Landfilling 2—1
Incineration •• 2—1
Ocean Disposal 2—1
3. PRELIMINARY HAZARD INDICES FOR BENZENE IN MUNICIPAL SEWAGE
SLUDGE 3—1
Landspreading and Distribution—and—Marketing 3—1
Landfilling .. 3—1
Index of groundwater concentration resulting
fromlandfilleds ludge(Index l)....... . . . ...... 3—1
•Index of human cancer risk resulting
from groundwater contamination (Index 2) . 3—7
Incineration 3—9
Index of air concentration increment resulting
from incinerator emissions (Index 1) 3—9
Index of human cancer risk resulting
from inhalation of incinerator emissions
(Index 2) 3—11
Ocean Disposal •.............. •i•.•..•.............. 3—13
4. PRELIMINARY DATA PROFILE FOR BENZENE IN MUNICIPAL SEWAGE
SLUDGE 4—1
Occurrence ....... 4—1
Sludge ••••......•.................. ... 4—1
Soil — Unpolluted . . . . . . . . . . . . . . . . . . . . . . . . . . . 4—1
Water — Unpolluted 4—2
Air .......... 4—2
Food •...................................... ......... 43
ii
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TABLE OF CONTENTS
(Continued)
Page
H an Effects •..... . ............ 4—4
Ingestion 44
Inhalation . 4—5
Plant Effects . . . . . . . . . . . 4—6
DomesticAnimalartdWildlifeEffects 4—6
Toxicity 4—6
Uptake . 4—6
Aquatic Life Effects 4—6
Toxicity .......... 4—6
Uptake 47
Soil Biota Effects 4—7
Physicochemical Data for Estimating Fate and Transport 4—7
5. REFERENCES 5—1
APPENDIX. PRELIMINARY HAZARD INDEX CALCULATIONS FOR
BENZENEINMIJNICIPALSEWACESLUDCE A—I
Li ].
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SECTION 1
INTRODUCTION
This preliminary data profile is one of a series of profiles
dealing with chemical pollutants potentially of concern in municipal
sewage sludges. Benzene was initially identified as being of potential
concern when sludge is placed in a landfill or incinerated.* This
profile is a compilation of information that may be useful in deter-
mining whether benzene poses an actual hazard to human health or the
environment when sludge is disposed of by these methods.
The focus of this document is the calculation of “preliminary
hazard indices” for selected potential exposure pathways, as shown in
Section 3. Each index illustrates the hazard that could result from
movement of a pollutant by a given pathway to cause a given effect
(e.g., sludge - groundwater - human toxicity). The values and assurnp—
tions employed in these calculations tend to represent a reasonable
“worst case”; analysis of error or uncertainty has been conducted to a
limited degree. The resulting value in most cases is indexed to unity;
i.e., values >1 may indicate a potential hazard, depending upon the
assumptions of the calculation.
The data used for index calculation have been selected or estimated
based on information presented in the “preliminary data profile”,
Section 4. Information in the profile is based on a compilation of the
recent literature. An attempt has been made to fill Out the profile
outline to the greatest extent possible. However, since this is a pre-
liminary analysis, the literature has not been exhaustively perused.
The “preliminary conclusions” drawn from each index in Section 3
are summarized in Section 2. The preliminary hazard indices will be
used as a screening tool to determine which pollutants and pathways may
pose a hazard. Where a potential hazard is indicated by interpretation
of these indices, further analysis will include a more detailed exami-
nation of potential risks as welL as an examination of site—specific
factors. These more rigorous evaluations may change the preliminary
conclusions presented in Section 2, which are based on a reasonable
“worst case” analysis.
The preliminary hazard indices for selected exposure routes
pertinent to landfilling and incineration practices are included in this
profile. The calculation formulae for these indices are shown in the
Appendix. The indices are rounded to two significant figures.
* Listings were determined by a series of expert workshops convened
during March—May, 1984 by the Office of Water Regulations and
Standards (OWRS) to discuss landspreading, landfilling, incineration,
and ocean disposal, respectively, of municipal sewage sludge.
1—1
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SECTION 2
PRELIMINARY CONCLUSIONS FOR BENZENE IN MUNICIPAL SEWAGE SLUDGE
The following preliminary conclusions hav been derived from the
caLculation of “preliminary hazard indices”, which represent conserva-
tive or “worst case” analyses of hazard. The indices and their basis
and interpretation are explained in Section 3. Their calculation
formulae are shown in the Appendix.
I. LANDSPREADINC AND DISTRIBUTION-AND—MARKETING --
Based on the recommendations of the experts at the OWRS meetings
(April—May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
II. LANDFILLING
Disposal of sludge in a landfill may be expected to result in
groundwater concentrations of benzene in the part—per—trillion
range for all scenarios, except possibly when all worst—case param-
eters occur. When all worst—case parameters occur, a groundwater
concentration of benzene in the part—per—billion range may be
expected (see Index 1).
Landfilling of sludge is not expected to result in an increase in
potential cancer risk to humans, except possibly when all viorst—
case parameters occur (see Index 2).
III. INCINERATION
Incineration of sludge is not expected to result in -benzene
concentrations in air that exceed background levels (see Index 1).
Sludge incineration is not expected to increase the potential
cancer risk to humans due to benzene (see Index 2).
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWRS meetings
(April—May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
2—1
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SECTION 3
PRELIMINARY LIAZARD INDICES FOR BENZENE
IN MUNICIPAL SEWAGE SLUDGE
I • LAIIDSPREADING AND DISTRIBUTION-AND—MARKETING
Based on the recommendations of the experts at the OWRS meetings
(April—May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option -i-n the future.
II. LANDFILLING
A. Index of Groundwater Concentration Resulting from Landfilled
Sludge (Index 1)
1. Explanation - Calculates groundwater contamination which
could occur in a potable aquifer in the Landfill vicin-
ity. Uses U.S. EPA’s Exposure Assessment Group (EAG)
model, “Rapid Assessment of Potential Groundwater Contam-
ination Under Emergency Response Conditions” (U.S. EPA,
1983a). Treats landfill leachate as a pulse input, i.e.,
the application of a constant source concentration for a
short time period relative to the time frame of the anal-
ysis. In order to predict pollutant movement in soils
and groundwater, parameters regarding transport and fate,
and boundary or source conditions are evaluated. Trans-
port parameters include the interstitial pore water
velocity and dispersion coefficient. Pollutant fate
parameters include the degradation/decay coefficient and
retardation factor. Retardation is primarily a function
of the adsorption process, which is characterized by a
linear, equilibrium partition coefficient representing
the ratio of adsorbed and solution pollutant conceritra—
tions. This partition coefficient, along with soil bulk
density and voLumetric water content, are used to calcu-
late the retardation factor. A computer program (in
FORTRAN) was developed to facilitate computation of the
analytical solution. The program predicts pollutant con-
centration as a function of time and Location in both the
unsaturated and saturated zone. Separate computations
and parameter estimates are required for each zone. The
prediction requires evaluations of four dimensionless
input values and subsequent evaluation of the result,
through use of the computer program.
2. Assumptions/Limitations — Conservatively assumes that the
pollutant is 100 percent mobilized in the leachate and
that all leachate leaks out of the landfill in a finite
period and undiluted by precipitation. Assumes that all
soil and aquifer properties are homogeneous and isotropic
throughout each zone; steady, uniform flow occurs only in
3—1
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the vertical direction throughout the unsaturated zone,
and only in the horizontal (longitudinal) plane in the
saturated zone; pollutant movement is considered only in
direction of groundwater flow for the saturated zone; all
pollutants exist in concentrations that do not signifi-
cantly affect water movement; for organic chemicals, the
background concentration in the soil profile or aquifer
prior to release from the source is assumed to be zero;
the pollutant source is a pulse input; no dilution of the
plume occurs by recharge from outside the source area;
the leachate is undiluted by aquifer flow within the
saturated zone; concentration in the saturated zone is
attenuated only by dispersion.
3. Data Used and Rationale
a. Unsaturated zone
i. Soil type and characteristics
(a) Soil type
Typical Sandy Loam
Worst Sandy
These two soil types were used by Gerritse et
- al. (1982) to measure partitioning of elements
between soil and a sewage sludge solution
phase. They are used here since these parti-
tioning measurements (i.e., Kd values) are con-
sidered the best available for analysis of
metal transport from landfilled sludge. The
same soil types are also used for nonmetals for
convenience and consistency of anaLysis.
(b) Dry bulk density ( dry)
Typical 1.53 g/mL
Worst 1.925 g/mL
Bulk density is the dry mass per unit volume of
the medium (soil), i.e., neglecting the mass of
the water (Camp Dresser and McKee, Inc. (CDM),
1984).
(c) Volumetric water content (0)
Typical 0.195 (unitLess)
Worst 0.133 (unitLess)
The volumetric water content is the volume of
water in a given volume of media, usually
expressed as a fraction or percent. It depends
on properties of the media and the water flux
3—2
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estimated by infiltration or net recharge. The
volumetric water content is used in calculating
the water movement through the unsaturated zone
(pore water velocity) and the retardation
coefficient. Values obtained from CDM, 1984.
(d) Fraction of organic carbon
Typical 0.005 (unitless)
Worst 0.0001 (unitless)
Organic content of soils-is described in terms
of percent organic carbon, which is required in
the estimation of partition coefficient, Kd.
Values, obtained from R. Griffin (1984) are
representative values for subsurface soils.
ii. Site parameters
(a) Landfill leaching time (LT) = 5 years
Sikora et al. (1982) monitored several sludge
entrenchment sites throughout the United States
and estimated time of landfill leaching to be A
or 5 years. Other types of landfills may leach
for longer periods of time; however, the use of
a value for entrenchment sites is conservative
because it results in a higher leachate
generation rate.
(b) Leachate generation rate (Q)
Typical 0.8 rn/year
Worst 1.6 rn/year
It is conservatively assumed that sludge
leachate enters the unsaturated zone undiluted
by precipitation or other recharge, that the
total volume of liquid in the sludge leaches
out of the landfill, and that leaching is com-
plete in 5 years. Landfilled sludge is assumed
to be 20 percent solids by volume, and depth of
sludge in the landfill is 5 in in the typical
case and 10 m in the worst case. Thus, the
initial depth of Liquid is 4 and 8 m, arid
average yearly leachate generation is 0.8 and
1.6 m, respectively.
(c) Depth to groundwater (h)
Typical 5 in
Worst 0 in
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Eight landfills were monitored throughout the
United States and depths to groundwater beLow
them were listed. A typical depth to ground-
water of 5 m was observed (u.s. EPA, 1977).
For the worst case, a value of 0 m is used to
represent the situation where the bottom of the
landfill is occasionally or regularly below the
water table. The depth to groundwater must be
estimated in order to evaluate the likelihood
that pollutants moving through the unsaturated
soil will reach the ground water.
(d) Dispersivity coefficient (a)
Typical 0.5 m
Worst Not applicable
The dispersion process is exceedingly complex
and difficult to quantify, especially for the
unsaturated zone. It is sometimes ignored in
the unsaturated zone, with the reasoning that
pore water velocities are usually large enough
so that pollutant transport by convection,
i.e., water movement, is paramount. As a rule
of thumb, dispersivity may be set equal to
10 percent of the distance measurement of the
analysis (Celhar and Axness, 1981). Thus,
based on depth to groundwater listed above, the
value for the typical case is 0.5 and chat for
the worst case does not apply since leachate
moves directly to the unsaturated zone.
iii. Chemical—specific parameters
(a) Sludge concentration of pollutant (Sc)
Typical 0.326 mg/kg DW
Worst 6.58 mg/kg DW
The typical and worst sludge concentrations are
the median and 95th percentile values derived
from data on 40 publicly—ocined treatment pLants
(POTWs) (U.S. EPA, 1982). (See Section 4,
p. 4—1.)
(b) Degradation rate (u) = 0.0107 day
The unsaturated zone can serve as an effective
medium for reducing pollutant concentration
through a variety of chemical and biological
decay mechanisms which transform or attenuate
the pollutant. While these decay processes are
usually compLex, they are approximated here by
a first—order rate constant. The degradation
rate is calculated using the following formula:
3—4
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0.693
11 = t4.
(u.s. EPA 1984b) (See Section 4, p. 4—2.)
(c) Organic carbon partition coefficient (K 0 ) =
74.2 mL/g
The organic carbon partition coefficient is
multiplied by the percent organic carbon
content of soil to derive a partition
coefficient (Kd), which r presents the ratio of
absorbed pollutant concentration to the
dissolved (Or solution) concentration. The
equation (Koc X oc assumes that organic
carbon in the soil is the primary means of
adsorbing organic compounds onto soils. This
concept serves to reduce much of the variation
in Kd values for different soil types. The
value of 1< is from Lyman, 1982.
b. Saturated zone
i. Soil type and characteristics
(a) Soil type
Typical Silty sand
Worst Sand
A silty sand having the values of aquifer por-
osity and hydraulic conductivity defined below
represents a typical aquifer material. A more
conductive medium such as sand transports the
plume more readily arid with less dispersion and
therefore represents a reasonable worst case.
(1) Aquifer porosity ( )
Typical 0.44 (unitless)
Worst 0.389 (unitless)
Porosity is that portion of the total volume of
soil, that is made up of voids (air) and water.
Values corresponding to the above soil types
are from Pettyjohn et al. (1982) as presented
in U.S. EPA (1983a).
(c) Hydraulic conductivity of the aquifer (K)
Typical 0.86 rn/day
Worst 4.04 rn/day
3—5
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The hydraulic conductivity (or permeability) of
the aquifer is needed to estimate flow velocity
based on Darcy’s Equation. It is a measure of
the volume of liquid that can flow through a
unit area or media with time; values can range
over nine orders of magnitude depending on the
nature of the media. Heterogenous conditions
produce large spatial variation in hydraulic
conductivity, making estimation of a single
effective value extremely difficult. Values
used are from Freeze and Cherry (1979) as
presented in U.S. EPA (198-3a).
(d) Fraction of organic carbon (HOC ) =
0.0 (unitLess)
Organic carbon content, and therefore adsorp-
tion, is assumed to be 0 in the saturated zone.
ii. Site parameters
(a) Average hydraulic gradient between landfill and
well Ci)
Typical 0.001 (unitless)
Worst 0.02 (unitless)
The hydraulic gradient is the slope of the
water table ri an unconfined aquifer, or the
piezometric surface for a confined aquifer.
The hydraulic gradient must be known to
determine the magnitude and direction of
groundwater flow. As gradient increases, dis-
persion is reduced. Estimates of typical and
high gradient values were provided by Donigian
(1985).
(b) Distance from well to landfill (A9)
Typical 100 m
Worst 50 m
This distance is the distance between a
landfill and any functioning public or private
water supply or livestock water supply.
(c) Dispersivity coefficient (a)
Typical 10 m
Worst 5 m
These values are 10 percent of the distance
from well to landfill (L 9 .), which is 100 and
50 in, respectively, for typical and worst
conditions.
3—6
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(d) Minimum thickness of saturated zone (B) = 2 m
The minimum aquifer thickness r-epresents the
assumed thickness due to preexisting flow;
i.e., in the absence of leachate. It is termed
the minimum thickness because in the vicinity
of the site it may be increased by leachate
infiltration from the site. A value of 2 m
represents a worst case assumption that
preexisting flow is very limited and therefore
dilution of the plume entering the saturated
zone is negligible.
(e) Width of landfill (w) = 112.8 m
The landfill is arbitrarily assumed to be
circular with an area of 10,000 m 2 .
iii. Chemical—specific parameters
(a) Degradation rate (p) = 0 day
Degradation is assumed not to occur in the
saturated zone.
(b) Background concentration of pollutant in
groundwater (BC) = 0 lig/L
It is assumed that no polLutant exists in the
soil profile or aquifer prior to release from
the source.
4. Index Values — See Table 3—1.
5. Value Interpretation — Value equals the maximum expected
groundwater concentration of pollutant, in Lig/L, at the
well.
6. Preliminary Conclusion — Disposal of sludge in a landfill
may be expected to result in groundwater concentrations
of benzerie in the part—per—trillion range for all scenar-
ios, except possibly when all worst—case parameters
occur. When all worst—case parameters occur, a ground-
water concentration of benzene in the part—per—billion
range may be expected.
B. Index of HnmAn Cancer Risk Resulting from Groundwater
Contamination (Index 2)
1. Explanation — Calculates human exposure which could
result from groundwater contamination. Compares exposure
with cancer risk—specific intake (asi) of pollutant.
3—7
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2. Assumptions/Limitations — Assumes long—term exposure to
maximum concentration at well at a rate of 2 Llday.
3. Data Used and Rationale
a. Index of groundwater concentration resulting from
landfilled sludge (Index 1)
See Section 3, p. 3—14.
b. Average humnn consumption of drinking water (Ac) =
2 L/day
The value of 2 L/day is a standard value used by
U.S. EPA in most risk assessment studies.
c. Average daily human dietary intake of pollutant (DI)
= 342 ug/day
The Department of National Health and Welfare of
Canada (1979) reported the estimated yearly human
intake of benzene for non—occupationally exposed
persons to be 125 mg/year or 342 big/day. The
National Cancer Institute (1977) estimated that an
individual might ingest as much as 250 jIg/day from
food (U.S. EPA, 1983b). Estimates of benzene in
food (such as eggs = 500 to 1,900 ng/g benzene) may
contribute to a relatively high DI when compared to
the cancer risk—specific intake (RSI) (see next par-
ameter) (U.S. EPA, 1980b). (See Section 4, pp. 4—3
and 4—4.)
d. Cancer potency = 4.5 x 1O (mg/kg/day)
The cancer potency derived by the U.S. EPA (1984a)
was based on data from a study in which oral
ingestion of benzene resulted in zymbal gland and
mammary cancer in rats. (See Section 4, p. 4—4.)
e. Cancer risk—specific intake (RSI) = 1.6 jig/day
The RSI is the pollutant intake value which results
in an increase in cancer risk of 1ü6 (1 per
1,000,000). The RSI is calculated from the cancer
potency using the folLowing formula:
RSI = 106 x 70 kg x i0 3 jig/mg
Cancer potency
4. Index 2 Values — See Table 3—1.
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5. Value Interpretation — Value >1 indicates a potential
increase in cancer risk of 10—6 (1 in 1,000,000). The
null index value should be used as a basis for comparison
to indicate the degree to which any risk is due to
landfill disposal, as opposed to preexisting dietary
sources.
6. Preliminary Conclusion — Landfilling of sludge is not
expected to result in an increase in potential cancer
risk to humans, except possibly when all worst—case
parameters occur.
III. INCINERATION
A. Index of Air Concentration Increment Resulting from
Incinerator Emissions (Index 1)
1. Explanation — Shows the degree of elevation of the
pollutant concentration in the air due to the incinera-
tion of sludge. An input sludge with thermal properties
defined by the energy parameter (EP) was analyzed using
the BURN model (CDM, 1984). This model uses the thermo—
dynamic and mass balance relationships appropriate for
multiple hearth incinerators to relate the input sLudge
characteristics to the stack gas parameters. Dilution
and dispersion of these stack gas releases were described
by the U.S. EPA’s Industrial Source Complex Long—Term
(ISCLT) dispersion model from which normalized annual
ground level concentrations were predicted (u.s. EPA,
1979). The predicted pollutant concentration can then be
compared to a ground level concentration used to assess
risk.
2. Assumptions/Limitations — The fluidized bed incinerator
was not chosen due to a paucity of available data.
Gradual plume rise, stack tip downwash, and building wake
effects are appropriate for describing plume behavior.
Maximum hourly impact values can be transLated into
annual average values.
3. Data Used and Rationale
a. Coefficient to correct for mass and time units (C) =
2.78 x 10 hr/sec x g/mg
b. Sludge feed rate (DS)
i. Typical = 2660 kg/hr (dry solids input)
A feed rate of 2660 kg/hr DW represents an
average dewatered sludge feed rate into the
furnace. This feed race would serve a commun-
ity of approximately 400,000 people. This rate
was incorporated into the U.S. EPA—ISCLT model
based on the following input data:
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EP = 360 lb H 2 0/nim BTU
Combustion zone temperature — 1400°F
Solids content — 28%
Stack height — 20 m
Exit gas velocity — 20 rn/s
Exit gas temperature — 356.9°K (183°F)
Stack diameter — 0.60 m
ii. Worst = 10,000 kg/hr (dry solids input)
A feed rate of 10,000 kg/hr DW represents a
higher feed rate and would serve a major U.S.
city. This rate was incorporated into the U.S.
EPA—ISCLT model based on the following input
data:
EP = 392 lb 11 2 0/mm BTU
Combustion zone temperature — 1400°F
Solids content — 26.6%
Stack height — 10 m
Exit gas velocity — 10 rn/s
Exit gas temperature — 313.8°K (105°F)
Stack diameter — 0.80 m
c. Sludge concentration of pollutant (Sc)
Typical 0.326 mg/kg DW
Worst 6.58 mg/kg DW
See Section 3, p. 3—4.
d. Fraction of pollutant emitted through stack (FM)
Typical 0.05 (unitless)
Worst 0.20 (unitless)
These values were chosen as best approximations of
the fraction of pollutant emitted through stacks
(Farrell, 1984). No data was avaiLable to validate
these values; however, U.S. EPA is currently testing
incinerators for organic emissions.
e. Dispersion parameter for estimating maximum annual
ground level concentration (DP)
Typical 3.4 g/m 3
Worst 16.0 ig/m 3
The dispersion parameter is derived from the U.S.
EPA—ISCLT short—stack model.
f. Background concentration of pollutant in urban
air (BA) = 14 pg/rn 3
3—10
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14 .ig/m 3 is the average of air concentrations from
three U.S. cities: 5, 18, and 19 g/rn 3 from Dallas,
-Chicago, and Los Angeles, respectively (u.s. EPA,
1983b). (See Section 4, p. 4—3.)
4. Index 1 Values
Sludge Feed
Fraction of Rate (kg/hr Dw)a
Pollutant Emitted Sludge
Through Stack Concentration 0 2660 10,000
Typical Typical 1.0 1.0 1.0
Worst 1.0 1.0 1.0
Worst Typical 1.0 1.0 1.0
Worst . 1.0 1.0 1.0
a The typical (3.4 .ig/m 3 ) and worst (16.0 1g/m 3 ) disper-
sion parameters will always correspond, respectively,
to the typical (2660 kg/hr DW) and worst (10,000 kg/hr
DW) sludge feed rates.
5. Value Interpretation — Value equals factor by which
expected air concentration exceeds background Levels due
to incinerator emissions.
6. Preliminary Conclusion — Incineration of sludge is not
expected to result in benzene concentrations in air that
exceed background levels.
B. Index of Human Cancer Risk Resulting from Inhalation
of Incinerator Emissions (Index 2)
1. Explanation — Shows the increase in human intake expected
to result from the incineration of sludge. Ground level
concentrations for carcinogens typically were developed
based upon assessments published by the U.S. EPA Carcino-
gen Assessment Group (CAG). These ambient concentrations
reflect a dose level which, for a lifetime exposure,
increases the risk of cancer by l06.
2. Assumptions/Limitations — The exposed population is
assumed to reside within the impacted area for 24
hours/day. A respiratory voLume of 20 m 3 /day is assumed
over a 70—year lifetime.
3—li
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3. Data Used and Rationale
a. Index of air concentration increment resulting from
incinerator emissions (Inde.x 1)
See Section 3, p. 3—11.
b. Background concentration of pollutant in urban air
(BA) = 14 g/m 3
See Section 3, p. 3—11.
c. Cancer potency = 2.6 x iO2 (rng/kg/dayY
Occupational exposure by inhalation has resulted in
leukemia in humans. A potency value of 5.2 x 10—2
(mg/kgldayY 1 , cited by U.S. EPA (1984a), included
an assumed absorption factor of 0.5, making this
latter value applicable to absorbed dose rather than
inhaled dose. To assess inhaled dose, the absorp-
tion factor has been removed, resulting in a value
of 2.6 x 102 (mg/kg/dayY 1 . (See Section 4,
p. 4—5.)
d. Exposure criterion (EC) = 0.13 ig/m 3
A lifetime exposure level which would result in a
106 cancer risk was selected as ground level con-
centration against which inc.inerator emissions are
compared. The risk estimates developed by CAG are
defined as the lifetime incremental cancer risk in a
hypothetical population exposed continuously
throughout their Lifetime to the stated concentra-
tion of the carcinogenic agent. The exposure
criterion is calculated using the following formula:
EC = IO 6 x 1g/mg x 70 kg
Cancer potency x 20 rn 3 /day
3—12
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4. Index 2 Values
Sludge Feed
Fraction of Rate (kg/hr DW)a
PolLutant Emitted Sludge
Through Stack Concentration 0 2660 10,000
Typical Typical 110 110 110
Worst 110 110 110
Worst Typical M-0 110 110
Worst 110 110 110
a The typical (3.4 .ig/m 3 ) and worst (16.0 g/rn 3 ) disper-
sion parameters will always correspond, respectively,
to the typical. (2660 kg/hr OW) and worst (10,000 kg/hr
DW) sludge feed rates.
5. Value Interpretation — Value > 1 indicates a potential
increase in cancer risk of > 10—6 (1 per 1,000,000).
Comparison with the null index value at 0 kg/hr DW
indicates the degree to which any hazard is due to sludge
incineration, as opposed to background urban air
concentration.
6. Preliminary Conclusion — Sludge incineration is not
expected to increase the potential cancer risk to humans
due to benzene.
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWRS meetings
(April—May, 1984), an assessemerit of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
3—13
-------
TABLE 3—1. INDEX OF GROUNDWATER CONCENTRATION RESULTING FROM LANDFILLED SLUDGE (INDEx 1) AND
INDEX OF HUMAN CANCER RISK RESULTING FROM CROUNDWATER CONTAMINATION (INDEX 2)
Site Characteristics
1
2
3
Con
dition
4
of An
alys
1 a,b,c
5
6
•
1
8
Sludge concentration
T
W
T
T
T
T
W
N
Unsaturated Zone
Soil type and charac—
ten St
Site parameterse
T
T
T
T
W
T
NA
W
T
T
T
T
NA
W
N
N
Saturated Zone
Soil type and charac-
teristics
Site parameters
T
T
T
T
T
T
T
T
W
T
T
W
W
W
N
N
Index 1 Value (pg/L)
2.6
x
i0
5.3 x i0
6.7
x
l0
8.9
x
l0
1.4
x i0
1.0
x
10—2
38
0
Index 2 Value
210
210
210
210
210
210
260
210
aT = Typical values used; W = worst—case values used; N = null condition, where no landfill exists, used as
basis for comparison; NA = not applicable for this condition.
blndex values for combinations other than those shown may be calculated using the formulae in the Appendix.
CSee Table A—i in Appendix for parameter values used.
dDry bulk density ( dry) ’ volumetric water content (0), and fraction of organic carbon ( 0 )•
eLeachate generation rate (Q), depth to groundwater (h), and dispersivity coefficient (a).
Aquifer porosity (0) and hydraulic conductivity of the aquifer (K).
SUydraulic gradient (i), distance from well to landfill ( Q ), and dispersivity coefficient (a).
-------
SECTION 4
PRELIMINARY DATA PROFILE FOR BENZENE IN MUNICIPAL SEWAGE SLUDGE
Benzene is produced principally from coal tar distillation, from
petroleum catalytic reforming of light naphthas, and in coal processing
and coal coking operations. It is used as an intermediate for the syn-
thesis of chemicals in the chemical and pharmaceutical industries, a
thinner for lacquer, a degreasing and cleaning agent, a solvent in the
rubber industry, an antiknock fuel additive, a general solvent in labor-
atories, and in the preparation and use of inks in the graphic arts
industry.
I. OCCURRENCE
A. Sludge
1. Frequency of Detection
Detected in 264 of 436 sampLes (61%) U.S. EPA, 1982
from 40 POTWs (p. 41)
Detected in 27 of 41 samples (66%) U.S. EPA, 1982
from 10 POTWs (p. 49)
2. Concentration
1 to 953 iiglL from 40 POTT.4s U.S. EPA, 1982
1 to 934 iigIL from 10 POT1 Js (p. 41,49)
Typical (median) 0.326 mg/kg DW Values statisti—
Worst (95th percentile) 6.58 mg/kg DW cally derived
from sludge
concentration
data presented
in U.S. EPA,
1982
B. Soil — Unpolluted
1. Frequency of Detection
Data not immediately available.
2. Concentration
Considering the solubility and volatility U.S. EPA, 1983b
of benzene, it can be concluded that (p. 5)
benzene may not persist in soil, and
volatilization and washout by rain
may be important processes for the
removal of benzene from soil.
4—1
-------
The degradation rate of benzene, U.S. EPA, 1984b
0.0107 (dayY 1 was derived by the
U.S. EPA (1984b).
C. Water — Unpolluted
1. Frequency of Detection
4 of 10 water supplies surveyed using U.S. EPA, 1980b
volatile organic analysis contained (p. C—i)
benzene.
2. Concentration
a. Freshwater
3100 g/L 24—hour average, U.S. EPA, 1980a
7000 j.ig/L ceiling, freshwater (p. 19)
aquatic life water quality criterion
b. Seawater
920 ig/L 24—hour average, U.S. EPA, 1980a
2100 .Lg/L ceiling, saltwater (p. 19)
aquatic life water quality criterion
c. Drinking Water
0.1 to 0.3 pgIL from water U.S. EPA, 1983b
supplies of 4 U.S. cities (p. 6)
10 .Ig/L highest concentration U.S. EPA, 1980b
observed in finished water
d. Groundwater
Coniglio et al. (1980) reported only U.S. EPA, 1984a
8.5% frequency of occurrence of (p. 1)
benzene in groundwater samples
throughout the United States.
D. Air
1. Frequency of Detection
Benzene comprises approximately 2.15% U.S. EPA, i980b
(by weight) of the total hydrocarbon (p. C—8)
emissions from a gasoline engine.
4—2
-------
2. Concentration
a. Urban
0.96 to 7.66 mg/rn 3 in air around gas U.S. EPA, 1980b
stations (p. Cz8)
0.048 mg/rn 3 average, 0.182 mg/rn 3 U.S. EPA, 1980b
maximum in Los Angeles air (p. C—B)
5 pg/rn 3 in Dallas air - U.S. EPA, 1983b
18 pg/rn 3 in Chicago air (p. 6)
19 g/m 3 in Los Angeles air
b. Rural
0.054 pg/rn 3 rural background level U.S. EPA, 1983b
(p. C—8)
E. Food
1. Total Average Intake
Benzene has been detected in various food U.S. EPA, 1983b
categories such as fruits, nuts, vege— (p. 6)
tables dairy products, meat, fish,
poultry, eggs, and several beverages.
The National Cancer Institute estimated
that an individuaL might ingest as much
as 250 pg/day of benzene from these
sources.
The estimated yearly human intake of Dept. National
benzene for those non—occupationally Health and
exposed is 125 mg/year. Welfare of
Canada, 1979
(p. 57)
2. Concentration
The U.S. EPA estimated the weight average U.S. EPA, 1983b
bioconcencration factor of benzene for (p. C—7)
the edible portion of shellfish and fish
consumed by Americans to be 5.21.
The exposure to benzene through general U.S. EPA, 1980b
dietary intake is not considered a (p. C—4)
problem for the general population.
4—3
-------
Estimated benzene level in food: U.S. EPA, 1980b
(p. C—5)
Benzene
Level
Food (nglg)
Heat treated or canned beef 2
Jamaican rum 120
Irradiated beef 19
Eggs 500—1,900
II. HUMAN EFFECTS
A. Ingestion
1. Carcinogenicity
a. Qualitative Assessment
There is limited evidence that U.S. EPA, 1984a
benzene is carcinogenic in animals (p. 12, 16)
by the oral route.
b. Potency
Cancer potency = 4.45 x lO U.S. EPA, 1984a
(mgIkg/day) based on a study in (p. 21)
which oral ingestion of benzene
resulted in zyinbal gland and mammary
cancer in rats.
c. Effects
Data not immediately available.
2. Chronic Toxicity
Data not immediately available.
3. Absorption Factor
t Ialf—life in water 1 to 6 days, estimated U.S. EPA, 1984a
from reaeration rate of 0.574 and the (p. 1)
oxygen reaeration rate of 0.19 day 1 to
0.96 day .
4. Existing Regulations
No standard for benzene in water exists, U.S. EPA, 1980b
but Cleland and Kingsburg (1977), using (p. C—61)
several assumptions and ACGIH air
standards, have suggested values of 1071
4—4
-------
and 414 ig/L for ingested water, and
107 iig/L for ingested water, based on
the potential carcinogenicity of benzene.
B. Inhalation
1. Carcinogenicity
a. Qualitative Assessment
There is sufficient evidence that
benzene is carcinogenic to humans
by inhalation.
Gerard and Revol (1970) and Gerard U.S. EPA, 1983b
et al. (1968) reported a significant (p. 11)
association between benzene exposure
and acute rnyeloblastic leukemia in
human epidemiologic studies.
b. Potency
Cancer potency = 2.6 x 10—2 U.S. EPA, 1984a
(mg/kg/dayY 1 . A potency value of (p. 22)
5.2 x 10—2 (mg/kgldayY 1 cited in
U.S. EPA, 1984a, included an assumed
absorption factor of 0.5, making the
latter value applicable to absorbed
dose rather than inhaled dose. To
assess inhaled dose, the absorption
factor has been removed resulting in
a value of 2.6 x 102 (mg/kgfday) .
c. Effects
Occupational exposure by inhalation U.S. EPA, 1984a
has resulted in leukemia in humans. (p. 22)
2. Chronic Toxicity
a. Inhalation Threshold or MPIH
Data not presented since cancer
potency is used to assess hazard.
b. Effects
Pancytopenia, impairment of U.S. EPA, 1983b
immunological system. (p. 15)
3. Absorption Factor
40 to 50 % retained at exposure to U.S. EPA, 1983b
< 110 ppm (p. 8)
4—5
-------
U.S. EPA, 1980b
(p. C—61)
U.S. EPA, 1983b
(p. 20)
U.S. EPA, 1980b
(p. c—b)
a. Acute
5300 ug/L
3100 j.ig/L proposed criteria
24—hr average
7000 ug/L ceiling level
9.5 ugIL in freshwater for sockeye
salmon
b. Chronic
Data not immediately available.
U.S. EPA,
(p. vi)
U.S. EPA,
(p. 19)
U.S. EPA,
U.S. EPA, 1980b
(p. vi)
28 to 34 absorption on exposure to
6000 ppm
4. Existing Regulations
25 ppm (80 mg/rn 3 ) ACGIH (1979)
10 ppm (30 mg/rn 3 ) ACCIH (1980)
III. PLANT EFFECTS
Data not immediately avaiLable.
IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS
A. Toxicity
See Table 4—1.
Benzene is biologicalLy converted to phenol
as well as catechol and hydroquenone.
B. Uptake
Data not immediately available.
V. AQUATIC LIFE EFFECTS
A. Toxicity
1. Freshwater
1980b
1980a
1983b
2. Saltwater
a. Acute
5100 ug/L
4—6
-------
920 ig/L 24—hr average proposed U.S. EPA, 1980a
criteria (p. 19)
2100 g/L ceiling level
4.9 j.xg/L in saltwater for sockeye U.S. EPA, 1983b
salmon (p. 20)
b. Chronic
700 ug/L resulted in adverse effects U.S. EPA, 1980b
on fish exposed 168 days. (p. vi)
B. Uptake
The weighted average bioconcentration factor U.S. EPA, 1980b
for benzene and the edible portion of all (p. C—7)
freshwater and estuarine aquatic organisms
consumed by Americans is calculated to be
5.21.
VI. SOIL BIOTA EFFECTS
Benzene can be degraded by a number of micro— U.S. EPA, l983b
organisms. In some instances the organism can (p. 3)
use benzene as a source of energy and carbon.
VII. PRYSICOCHEMICAL DATA FOR ESTIMATING FATE AND TRANSPORT
Molecular weight: 78.12 U.S. EPA, l983b
(p. 1)
Volatile, colorless, liquid hydrocarbon
Boiling point: 80.1°C
Melting point: 5.5°C
Water solubility: 1780 mg/L at 25°C
Density: 0.87865 g/mL at 20°C
4.8 hour volatilization half—life in 1 meter U.S. EPA, 1983b
water column at 25°C (p. 3)
Based on an organic content of 2.6%, the U.S. EPA, 1983b
Freudlich adsorption constant for a silty (p. 5)
clay loam has been determined to be 2.4.
Organic carbon partition coefficient (K ) = Estimated from
74.2 rnL/g Lyman, 1982
4—7
-------
TABLE 4-1. TOXICITY OF BENZENE TO DOMESTIC ANIMALS AND WILDLIFE
Chemical
Form
Feed
Concentration
Water
Concentration
Daily Intake
Duration
Species (N) 8 Administered
( ig/g
OW)
(mgIL)
(mg/kg OW)
of
Study Effects References
Rat (3D/sex) Beniene iii gavage NR 50 52 weeks Control: 1130 male, U.S. EPA, 1983b
1/30 female developed (p. 10)
leukemia; 0/30 male,
0/30 female developed
xymbal gland carcinoma
and skin carcinoma
50 mg/kg group; 2/30 male,
2/30 female developed
Leukemia; 0/30 male,
2/30 female developed
symbal gland carcinoma
Rat (35/sex) Renzene in gavage Ilk 250 50 weeks Control: see above
250 mg/kg group: 4/35 male, U.S. EPA, 1983b
1/35 female developed (p. 10)
leukemia; 8/35 female,
0/35 male developed zymbal
gland carcinoma; 2/35 femaLe,
0/35 male deveLoped skin
carcinoma
Nice Benzene in gavage NH 0.3— 1 Days 6 to 15 Maternal toxicity and U.S. EPA, 1983b
of gestation embryonic reabsorption (p. 14)
but no malformations
Number of experimental snimals when reported.
bIlE Not reported.
-------
SECTION 5
REFERENCES
Abramowitz, M., and I. A. Stegun. 1972. Handbook of Mathematical
Functions. Dover Publications, New York, NY.
Camp Dresser and McKee, Inc. 1984. Development of Methodologies for
Evaluating Permissible Contaminant Levels in Municipal Wastewater
Sludges. Draft. Office of Water Regulations and Standards, U.S.
Environmental Protpction Agency, Washington, D.C.
Department of National Health and Welfare of Canada. 1979. Benzene:
Human Health Implications of Benzene at Levels Found in the
Canadian Environment and Workplace. 79—EHD—40. Department of
National Health and Welfare, Ottawa, Canada. 161 pp.
Donigian, A. S., 1985. Personal Communication. Anderson—Nichols & Co.,
Inc., Palo Alto, CA. May.
Farrell, J. 1984. Personal Communication. Water Engineering Research
Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH.
December.
Freeze, R. A., and J. A. Cherry. 1979. Groundwater. Prentice—Hall,
Inc., Englewood Cliffs, NJ.
Geihar, L. W., and C. J. Axness. 1981. Stochastic Analysis of
Macrodispersion in 3—Dimensionally Heterogeneous Aquifers. Report
No. H—8. Hydrologic Research Program, New Mexico Institute of
Mining and Technology, Soccorro, NM.
Gerritse, R. C., R. Vriesema, J. W. Dalenberg, and H. P. DeRoos. 1982.
Effect on Sewage Sludge on Trace Element Mobility in Soils. J.
Environ. Qual. 2:359—363.
Griffin, R. A. 1984. Personal Communication to U.S. Environmental
Protection Agency, ECAO — Cincinnati, OH. Illinois State
Geological Survey.
Lyman, W. J. 1982. Adsorption Coefficients for Soils and Sediments.
Chap. 4. In: Handbook of Chemical Property Estimation Methods.
McGraw—Hill Book Co., New York, NY.
Pettyjohn, W. A., D. C. Kent, T. A. Prickett, H. E. LeGrand, and F. E.
Witz. 1982. Methods for the Prediction of Leachate Plume
Migration and Mixing. U.S. EPA Municipal Environmental Research
Laboratory, Cincinnati, OH.
Sikora, L. J., W. D. Burge, and J. E. Jones. 1982. Monitoring of a
Municipal Sludge Entrenchment Site. J. Environ. Qual. 2(2):
321—325.
5—1
-------
U.S. Environmental Protection Agency. 1977. Environmental Assessment
of Subsurface Disposal of Municipal Waste Water Sludge. Interim
Report. EPA/530/SW—547. Municipal Environmental. Research
Laboratory, Cincinnati, OH.
U.S. Environmental Protection Agency. 1979. Industrial Source Complex
CISC) Dispersion Model. User Guide. EPA 450/4—79—30. Vol. 1.
Office of Air Quality Planning and Standards, Research Triangle
Park, NC. December.
U.S. Environmental Protection Agency. ].980a. Potential Health Effects
from Persistent Organics in Wastewater and 1udges Used for Land
Application. EPA—600/l—80—025. Health Effects Research
Laboratory, Cincinnati, OH.
U.S. Environmental Protection Agency. 1980b. Ambient Water Quality
Criteria for Benzene. EPA 440/5—80—018. Criteria and Standards
Division, Washington, D.C., p. 125.
U.S. Environmental Protection Agency. 1982. Fate of Priority
Pollutants in Publicly—Owned Treatment Works. Final Report.
Vol. 1. EPA 440/1—82—303. Effluent Guidelines Division,
Washington, D.C. September.
U.S. Environmental Protection Agency. l983a. Rapid Assessment of
Potential Groundwater Contamination Under Emergency Response
Conditions. EPA 600/8—83—030.
U.S. Environmental Protection Agency. 1983b. Hazard Profile for
Benzene. Preliminary Review- Draft Document. ECAO—CIN.
Environmental Criteria and Assessment Office, Cincinnati, OH.
U.S. Environmental Protection Agency. 1984a. Health Effects Assessment
for Benzene. ECAO—CIN—H037. Environmental Criteria and Assessment
Office, Cincinnati, OH, p. 44.
U.S. Environmental Protection Agency. 1984b. Suggested SeLection
Criteria for the WHO—HEAL Project Including a Preliminary List of
Pollutants. Draft. ECAO—CIN. February 2.
5—2
-------
APPENDIX
PRELIMINARY HAZARD INDEX CALCULATIONS FOR BENZENE
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPRRADING AND DISTRIBUTION—AND—MARKETING
Based on the recommendations of the experts at the OWRS meetings
(April—May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such assessment for this option in—the future.
II. LANDFILLING
A. Procedure
Using Equation 1, several values of C/C 0 for the unsaturated
zone are calculated corresponding to increasing values of t
until equilibrium is reached. Assuming a 5—year pulse input
from the landfill, Equation 3 is employed to estimate the con-
centration vs. time data at the water table. The concentration
vs. time curve is then transformed into a square pulse having a
constant concentration equal to the peak concentration, Cu,
from the unsaturated zone, and a duration, to, chosen so that
the total areas under the curve and the pulse are equal, as
illustrated in Equation 3. This square pulse is then used as
the input to the linkage assessment, Equation 2, which esti-
mates initial dilution in the aquifer to give the initial con-
centration, C 0 , fo the saturated zone assessment. (Conditions
for B, minimum thickness of unsaturated zone, have been set
such that dilution is actually negligible.) The saturated zone
assessment procedure is nearly identical to that for the unsat-
urated zone except for the definition of certain parameters and
choice of parameter values. The maximum concentration at the
well, is used to calculate the index values given in
Equations 4 and 5.
B. Equation 1: Transport Assessment
C(X,t ) = 4 [ exp(A 1 ) erfc(A 2 ) + exp(B 1 ) erfc(B 2 )] = P( ,t)
Co
Requires evaluations of four dimensionless input values and
subsequent evaluation ofA the result. Exp(A 1 ) denotes the
exponential of A 1 , e , where erfc(A 2 ) denotes the
complimentary error function of A 2 . Erfc(A 2 ) produces values
between 0.0 and 2.0 (Abramowitz and Stegun, 1972).
A-I
-------
where:
A =L (Vt— (V* 2 +4D*x p )+J
2D*
A _ X _ t(v 2+4D*x1 )
2 — (4D* x
B =X.__ [ V*+ (V* 2 +AD*x .t*)+]
1 2D*
B _ t+4Dx
2 — (4D* x
and where for the unsaturated zone:
C 0 = Sc x CF = Initial leachate concentration ( ig/L)
SC Sludge concentration of pollutant (mg/kg DW)
CF = 250 kg sludge solids/rn 3 leachate =
PS x
1 — PS
PS = Percent solids (by weight) of landfilled sludge =
20
t = Time (years)
X = h = Depth to groundwater (m)
= a x (m 2 /year)
a Dispersivity coefficient (m)
v* = Q (rn/year)
e xR
Q = Leachace generation rate (rn/year)
0 = Volumetric water content (unitless)
a = 1 + dry x = Retardation factor (unitless)
e
dry = Dry bulk density (g/rnL)
Kd = OC X Koc (mL/g)
= Fraction of organic carbon (unicless)
= Organic carbon partition coefficient (mLIg)
365xii —l
= R (years)
= Degradation rate (day )
and where for the saturated zone:
C 0 = Initial concentration of pollutant in aquifer as
determined by Equation 2 ( ig/L)
t = Time (years)
x = A9.. = Distance from well to landfill (m)
D* = a x V* (m 2 /year)
a = Dispersivicy coefficient (m)
A-2
-------
v = K X (rn/year)
øxR
K = Hydraulic conductivity of the aquifer (rn/day)
i = Average hydraulic gradient between landfill arid well
(unitless)
0 = Aquifer porosity (unitless)
R = i + dry x Kd = Retardation factor = 1 (unitless)
0
since d = OC x K 0 and is assumed to be zero
for the saturated zone.
C. Equation 2. Linkage Assessment
— QxW
C O — Cu x 365 [ (K x 1) £ 0] x B
where:
C 0 = Initial concentration of pollutant in the saturated
zone as determined by Equation 1 (i.ig/L)
Cu = Maximum pulse concentration from the unsaturated
zone ( ig/L)
Q = Leachate generation rate (rn/year)
W = Width of landfill (m)
K = Hydraulic conductivity of the aquifer (rn/day)
i = Average hydraulic gradient between landfill and well
(unitless)
0 = Aquifer porosity (unitless)
B = Thickness of saturated zone (rn) where:
QxWxO
B> andB>2
— Kxix365 —
D. Equation 3. Pulse Assessment
C( ,: ) = P(x,t) for 0 < t < to
= P(x,t) — P(x,t — t 0 ) for t > to
where:
to (for unsaturated zone) = LT = Landfill leaching time
(years)
to (for saturated zone) = Pulse duration at the water
table (x = h) as determined by the following equation:
to = [ f Cdtl
P( ,t) = t ) as determined by Equation 1
A—3
-------
E. Equation 4. Index of Groundwater Concentration Resulting
from Landfilled Sludge (Index 1)
1. Formula
Index 1 =
where:
Cmax = Maximum concentration of pollutant at well =
maximum of C(M ,t) calculated in Equation 1
( g/L) --
2. Sample Calculation
2.621 x iO gIL = 2.621 x 1O ugiL
F. Equation 5. Index of Human Cancer Risk Resulting
from Groundwater Contamination (Index 2)
1. Formula
( Ii x AC) + DI
Index 2 = RSI
where:
Ii = Index 1 = Index of groundwater concentration
resulting from landfilled sludge (jiglL)
AC Average human consumption of drinking water
(L/day)
DI = Average daily human dietary intake of pollutant
(iig/day)
RSI = Cancer risk—specific intake ( .igIday)
2. Sample Calculation
213.8 = ( 2.621 x iO pg/L x 2 L/day) + 342 igfday
1.6 ig/day
III. INCINERATION
A. Index of Air Concentration Increment Resulting from Incinerator
Emissions (Index 1)
1. Formula
( C x DS x SC x FM x DP) + BA
Index 1 =
A-4
-------
where:
C = Coefficient to correct for mass and time units
(hr/sec x g/mg)
DS = Sludge feed rate (kg/hr DW)
SC = Sludge concentration of pollutant (mg/kg DW)
FM = Fraction of pollutant emitted through stack (unitless)
DP = Dispersion parameter for estimating maximum
annual ground level, concentration (iig/m 3 )
BA = Background concentration of pollutant in urban
air (iig/m 3 )
2. Sample Calculation
1.000 = [ (2.78 x i0 hr/sec x g/mg x 2660 kg/hr DW x 0.326 mg/kg DW
x 0.05 x 3.4 iig/m 3 ) + 14 iig/m 3 ] 14 i.ig/m 3
B. Index of HnmRn Cancer Risk Resulting from Inhalation of
Incinerator Emissions (Index 2)
1. Formula
[ ( 1 i — 1) x BA] + BA
Index 2 = EC
where:
= Index I = Index of air concentration incr ment
resulting from incinerator emissions
(unit]. e ss)
BA = Background concentration of pollutant in
- urban air (ug/m 3 )
EC = Exposure criterion (hg/rn 3 )
2. Sample Calculation
107 7 — [ (1.000 — 1) x 14 ij /m 3 ] + 14 g/m 3
— 0.13 jig/rn 3
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWRS meetings
(April—May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
A-S
-------
TARLE A—i. INPUT DATA VARYING IN LANDFILL ANALYSIS AND RESULT FOR EACH CONDITION
Condition of Analysis
Input Data 1 2 3 4 5 6 7 8
0
Sludge concentration of pollutant, SC (pglg Ow)
Unsaturated zone
Soil type and characteristics
Dry bulk density, 1 ’dry (g/m
Volumetric water content, 0 (unitless)
Fraction of organic carbon, 1 oc (unitless)
1.53
0.195
0.005
1.53
0.195
0.005
1.925
0.133
0.0001
NAb
NA
NA
1.53
0.195
0.005
1.53
0.195
0.005
NA
NA
NA
N
N
N
Site parameters
Leachate generaLion rate, Q (mfyear)
Depth to groundwater, h (in)
Dispersivity coefficient, Cm)
0.8
5
0.5
0.8
5
0.5
0.8
5
0.5
1.6
0
NA
0.8
5
0.5
0.8
5
0.5
1.6
0
NA
N
N
N
Saturated zone
Soil type and characteristics
Aquifer poros Ity, 0 (unitless)
Hydraulic conductivity of the aquifer,
K (rn/day)
0.44
0.86
0.44
0.86
0.44
0.86
0.44
0.86
0.369
4.04
0.44
0.86
0.389
4.04
N
N
Site parameters
Hydraulic gradient, I (uniLless)
Distance from well Lo landfill, M. (in)
Dispersivity coefficient, a Cm)
0.001
100
10
0.02
50
5
0.02
50
5
0.001
100
10
0.001
100
10
0.001
100
10
0 • 001
100
10
N
N
N
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TABLE A—i. (continued)
Condition of Analysis
1 2 3 4 5 6 7 8
81.5
1650
81.5
81.5
81.5
81.5
1645
H
2.392
48.28
6.172
81.5
2.392
2.392
1645
N
5.040
5.040
5.000
5.000
5.040
5.040
5.000
N
126
126
126
253
23.8
6.32
2.38
N
2.39
48.3
6.17
81.5
2.39
2.39
1650
N
Results
Unsaturated zone assessment (Equations 1 and 3)
Initial Leachate concentration, C 0 (iig/L)
Peak concentration, Cu (pg/I)
Pulse duration, t 0 (years)
Linkage assessment (Equation 2)
Aquifer thickness, B Cm)
Initial concentration in saturated zone, C 0
(pgiL)
Saturated zone assessment (Equations 1 and 3)
.
Maximum well concentration, Cma5 (pg/L)
0.0002621
0.005292
0.0006711
0.008862
0.001393
0.01049
38.07
N
Index of groundwater concentration resulting
from landfilled sludge, Index 1 Cpg/L)
(Equation 4)
0.0002621
0.005292
0.0006711
0.008862
0.001393
0.01049
38.01
0
Index of human cancer risk resulting
from groundwater contamination, Index 2
(unitless) (Equation 5)
213.8
213.8
213.8
213.8
213.8
213.8
261.3
213.8
Null condition, where no landfill exists; no value is used.
bNA Not applicable for this condition.
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