United Slates
Environmenta! Protection
Agency
Office o; Water
Regulations ana Standards
Washington, DC 20460
Water
Juns, 1985
Environmental Profs
and Hazard Indices
for Constituents
of Municipal Sludge;
Chromium
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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 arid 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 OP CONTENTS
Page
PREFACE i
1. INTRODUCTION 1-1
2. PRELIMINARY CONCLUSIONS FOR CHROMIUM IN MUNICIPAL SEWAGE
SLUDGE 2-1
Landspreading and Distribution-and-Mark.eti.ng 2-1
Landfilling 2-2
Incineration 2-2
Ocean Disposal 2-2
3. PRELIMINARY HAZARD INDICES FOR CHROMIUM IN MUNICIPAL SEWAGE
SLUDGE 3-1
Landspreading and Distribution-and-Marketing 3-1
Effect on soil concentration of chromium (Index 1) 3-1
Effect on soil biota and predators of soil biota
(Indices 2-3) 3-2
Effect on plants and plant tissue
concentration (Indices 4-6) 3-5
Effect on herbivorous animals (Indices 7-8) 3-9
Effect on humans (Indices 9-13) 3-12
Landfilling 3-20
Index of groundwater concentration increment resulting
from landfilled sludge (Index 1) 3-20
Index of human toxicity resulting from
groundwater contamination (Index 2) 3-26
Incineration 3-28
Index of air concentration increment resulting
from incinerator emissions (Index 1) 3-28
Index of human cancer risk resulting from
inhalation of incinerator emissions
(Index 2) 3-31
Ocean Disposal 3-32
11
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TABLE OP CONTENTS
(Continued)
Page
4. PRELIMINARY DATA PROFILE FOR CHROMIUM IN MUNICIPAL SEWAGE
SLUDGE 4~X
Occurrence 4
Sludge J"1
Soil - Unpolluted *~l
Water - Unpolluted 4~2
Air 4"4
Food 4"4
Human Effects 4~"5
Ingestion -
Inhalation 4"6
Plant Effects 4"8
Phytotoxicity 4~8
Uptake 4"8
Domestic Animal and Wildlife Effects 4-8
Toxicity 4~8
Uptake 4"8
Aquatic Life Effects 4~8
Toxicity A~8
Uptake 4"9
Soil Biota Effects 4"9
Physicochemical Data for Estimating Fate and Transport 4-10
5. REFERENCES 5-I
APPENDIX. PRELIMINARY HAZARD INDEX CALCULATIONS FOR
CHROMIUM IN MUNICIPAL SEWAGE SLUDGE A-l
ill
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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. Chromium (Cr) was initially identified as being of
potential concern when sludge is landspread (including distribution and
marketing), placed in a landfill, or incinerated.* This profile is a
compilation of information that may be useful in determining whether Cr
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 + soil » plant uptake * animal uptake * human toxicity).
The values and assumptions employedin 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 landspreading and distribution and marketing, landfilling,
and incineration practices are included in this profile. The calcula-
tion 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 (OWES) to discuss landspreading, landfilling, incineration,
and ocean disposal, respectively, of municipal sewage sludge.
1-1
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SECTION 2
PRELIMINARY CONCLUSIONS FOR CHROMIUM IN MUNICIPAL SEWAGE SLUDGE
The following preliminary conclusions have 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. LANDSPREADING AND DISTRIBUTION-AMD-MARKETING
A. Effect on Soil Concentration of Chromium
Landspreading of sludge is not expected to increase the soil
concentration of Cr except when sludge containing a typical
concentration of Cr is applied at a high rate or when sludge
containing a high concentration of Cr is applied at medium to
high rates (see Index 1).
B. Effect on Soil Biota and Predators of Soil Biota
Conclusions concerning soil biota toxicity were not drawn due
to lack of data (see Index 2). Landspreading of sludge is not
expected to pose a toxic hazard due to Cr for predators of
soil biota (see Index 3).
C. Effect on Plants and Plant Tissue Concentration
Landspreading of sludge is not expected to produce soil
concentrations of Cr which pose a phytotoxic hazard except
possibly when sludge containing a high concentration of Cr is
applied at a high rate (see Index 4). The concentrations of
Cr in tissues of 'plants in the animal and human diet are
expected to increase above background levels when sludge is
landspread; these increases may be substantial when sludge
containing a high concentration of Cr is applied at a high rate
(see Index 5). The substantial increases in plant tissue
concentration of Cr predicted when high-Cr sludge is land-
spread at a high rate may be precluded by phytotoxicity (see
Index 6).
D. Effect on Herbivorous Animals
Landspreading of sludge is not expected to result in plant
tissue concentrations of Cr that pose a toxic hazard to
animals consuming forage crops (see Index 7). Toxicity to
herbivorous animals through direct ingestion of sludge or
sludge-amended soil is not expected to occur (see Index 8).
2-1
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B. Effect on Humans
Human intake of Cr through the consumption of plants grown in
sludge-amended soil is not expected to pose a health threat
(see Index 9). A health threat due to Cr is not expected for
humans who consume animal products derived from animals
feeding on plants grown in sludge-amended soil (see Index 10).
Human intake of Cr through consumption of animal products
derived from animals which have ingested sludge-amended soil
or pure sludge is not expected to pose a health threat (see
Index 11). The direct ingestion of sludge-amended soil or
pure sludge by humans is likewise not expected to pose a
health threat due to Cr (see Index 12). The aggregate amount
of Cr in the human diet resulting from landspreading of sludge
is not expected to pose a health threat (see Index 13).
II. LAHDPILLIMG
Groundwater concentration of Cr at the well are expected to
increase above background concentrations when sludge is landfilled;
this increase may be substantial at a disposal site with all worst-
case conditions (see Index 1). Groundwater contamination produced
by landfilled sludge is not expected to pose a human health threat
due to Cr (see Index 2).
III. INCINEHATIOH
Incineration of sludge is expected to increase air concentrations
of Cr above background levels; this increase may be substantial
when sludge containing a high concentration of Cr is incinerated at
a high feed rate (see Index 1). Inhalation of emissions from
sludge incineration is expected to increase the human cancer risk
due to Cr above the risk posed by background urban air
concentrations of Cr. This increase in cancer risk may be
substantial when high-Cf sludge is incinerated at a high feed rate
(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.
2-2
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SECTION 3
PRELIMINARY HAZARD INDICES FOR CHROMIUM
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING
A. Effect on Soil Concentration of Chromium
1. Index of Soil Concentration Increment (Index 1)
a. Explanation - Shows degree of elevation of pollutant
concentration in soil to which sludge is applied.
Calculated for sludges with typical (median if
available) and worst (95th percentile if available)
pollutant concentrations, respectively, for each of
four sludge loadings. Applications (as dry matter)
are chosen and explained as follows:
0 mt/ha No sludge applied. Shown for all indices
for purposes of comparison, to distin-
guish hazard posed by sludge from pre-
existing hazard posed by background
levels or other sources of the pollutant.
5 mt/ha Sustainable yearly agronomic application;
i.e., loading typical of agricultural
practice, supplying ^50 kg available
nitrogen per hectare.
50 mt/ha Higher application as may be used on
public lands, reclaimed areas or home
gardens.
500 mt/ha Cumulative loading after years of
application.
b. Assumptions/Limitations - Assumes pollutant is dis-
tributed and retained within the upper 15 cm of soil
(i.e., the plow layer), which has an approximate
mass (dry matter) of 2 x 103 mt/ha.
c. Data Used and Rationale
i. Sludge concentration of pollutant (SC)
Typical 230.1 Ug/g DW
Worst 1499.7 Ug/g DW
Hexavalent Cr (Cr VI) is a strong oxidizing
agent and is readily reduced to trivalent Cr
(Cr III) in the presence of organic matter,
such as untreated sewage (U.S. EPA, 1978). Cr
3-1
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in treated sewage sludge, as in untreated
sewage, is assumed to be in sufficient contact
with organic matter that the remaining hex-
avalent Cr is reduced to the trivalent form
(Cr III). Therefore, trivalent Cr values are
used in calculating hazard indices for land-
spreading and landfilling. However, hexavalent
Cr values are used in calculating hazard
indices for incineration due to the high tem-
peratures in the combustion chamber. The
typical and worst sludge concentrations are the
median and 95th percentile values statistically
derived from sludge concentration data from a
survey of 40 publicly-owned treatment works
(POTWs) (U.S. EPA, 1982). (See Section 4,
p. 4-1.)
ii. Background concentration of pollutant in soil
(BS) = 100 ug/g DW
Allaway (1968) reported a mean of 100 ppm Cr in
natural soils ranging from 5 to 3000 ppm. (See
Section 4, p. 4-2.)
d. Index 1 Values
Sludge Application Rate (rot/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
1
1
1.0
1.0
1.0
1.3
1.3
3.8
e. Value Interpretation - Value equals factor by which
expected ' soil concentration exceeds background when
sludge is applied. (A value of 2 indicates concen-
tration is doubled; a value of 0.5 indicates
reduction by one-half.)
f. Preliminary Conclusion - Landspreading o£ sludge is
not expected to increase the soil concentration of
Cr except when sludge containing a typical
concentration of Cr is applied at a high rate or
when sludge containing a high concentration of Cr is
applied at medium to high rates (see Index 1).
B. Effect on Soil Biota and Predators of Soil Biota
1. Index of Soil Biota Toxicity (Index 2)
a. Explanation - Compares pollutant concentrations in
sludge-amended soil with soil concentration shown to
be toxic for some organism.
3-2
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b. Assumptions/Limitations - Assumes pollutant form in
sludge-amended soil is equally bioavailable and
toxic as form used in study where toxic effects were
demonstrated.
c. Data Used and Rationale
i. Index of soil concentration increment (Index 1)
See Section 3, p. 3-2.
ii. Background concentration of pollutant in soil
(BS) = 100 Ug/g DW
See Section 3, p. 3-2.
iii. Soil concentration toxic to soil biota (IB) -
Data not immediately available.
d. Index 2 Values - Values were not calculated due to
lack of data.
e. Value Interpretation - Value equals factor by which
expected soil concentration exceeds toxic concentra-
tion. Value >1 indicates a toxic hazard may exist
for soil biota.
f. Preliminary Conclusion - Conclusion was not drawn
because index values could not be calculated.
Index of Soil Biota Predator Toxicity (Index 3)
a. Explanation - Compares pollutant concentrations
expected in tissues of organisms inhabiting sludge-
amended soil with food concentration shown to be
toxic to a predator on soil organisms.
b. Assumptions/Limitations - Assumes pollutant form
bioconcentrated by soil biota is equivalent in cox-
icity to form used to demonstrate toxic effects in
predator. Effect level in predator may be estimated
from that in a different species.
c. Data Used and Rationale
i. Index of soil concentration increment (Index 1)
See Section 3, p. 3-2.
ii. Background concentration of pollutant in soil
(BS) = 100 Ug/g DW
See Section 3, p. 3-2.
3-3
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iii. Uptake slope of pollutant in soil biota (UB) =
0.5 ug/g tissue DW (ug/g soil DW)"1
Helmke et al. (1979) measured the uptake of
metals in earthworms from sewage sludge-amended
plots and concluded that Cr is not taken up to
a significant degree; that is, the Cr concen-
tration in the soil material ingested by the
earthworm is nearly equivalent to that in the
excreted cast and the concentration in the worm
body is virtually unchanged by sludge applica-
tion. However, since a predator ingesting an
earthworm also ingests the soil material it
contains, predator Cr intake will be affected
by sludge application. Information on the
relative dry weight of earthworm gut contents
alone and total weight including gut contents
is not immediately available. If it is assumed
that gut contents constitute 50 percent of
total dry weight, then an uptake factor of
0.5 Mg/g tissue DW (yg/g soil DW)"1 would be
the minimum value to use, where "tissue" is
understood to be the total amount ingested by
the predator.
iv. Background concentration in soil biota (BB) =
50.5 ug/g DW
In the study described above, Helmke et al.
(1979) found that the Cr concentration in
worms, after correction for contamination by
casts, was approximately 1.0 yg/g DW. Follow-
ing the above assumption that the whole worm is
50 percent soil by dry weight, the background
concentration in worms is (BS + 1.0 ug/g)/2 =
50.5 ug/g DW.
v. Feed concentration toxic to predator (TR) =
2000 ug/g DW
Data presented by MAS (1980) (see Section 4,
p. 4-15) show no adverse effects of Cr III
ingestion except when a concentration of
2000 ug Cr/g feed (assume DW) was fed to
chickens for 21 days. This exposure level
resulted in reduced growth. Lacking data on
adverse effect levels for Cr III in any other
species, the value of 2000 Ug/g DW is used as
the feed concentration toxic to predators of
soil biota.
3-4
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d. Index 3 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration
Typical
Worst
0
0.025
0.025
5
0.025
0.026
50
0.026
0.034
500
0.032
0.095
e. Value Interpretation - Value equals factor by which
expected concentration in soil biota exceeds that
which is toxic to predator. Value > 1 indicates a
toxic hazard may exist for predators of soil biota.
f. Preliminary Conclusion - Landspreading of sludge is
not expected to pose a toxic hazard due to Cr for
predators of soil biota.
C. Effect on Plants and Plant Tissue Concentration
1. Index of Phytotoxicity (Index 4)
a. Explanation - Compares pollutant concentrations in
sludge-amended soil with the lowest soil concentra-
tion shown to be toxic for some plant.
b. Assumptions/Limitations - Assumes pollutant form in
sludge-amended soil is equally bioavailable and
toxic as form used in study where toxic effects were
demonstrated.
c. Data Used and Rationale
i. Index of soil concentration increment (Index 1)
See Section 3, p. 3-2.
ii. Background concentration of pollutant, in soil
(BS) = 100 Ug/g DW
See Section 3, p. 3-2.
iii. Soil concentration toxic to plants (TP) =
200 Ug/g DW
200 Ug/g DW is the lowest soil concentration of
Cr at which an adverse effect was observed
(bean plant) (Council for Agricultural Science
and Technology (CAST), 1976). A 25% yield
reduction is associated with 200 Ug/g DW Cr in
soil. (See Section 4, p. 4-11.)
3-5
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d. Index 4 Values
Sj.udge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
0.50
0.50
0.50
0.52
0.52
0.67
0.63
1.9
e. Value Interpretation - Value equals factor by which
soil concentration exceeds phytotoxic concentration.
Value > 1 indicates a phytotoxic hazard may exist.
f. Preliminary Conclusion - Landspreading of sludge is
not expected to produce soil concentrations of Cr
which pose a phytotoxic hazard except possibly when
sludge containing a high concentration of Cr is
applied at a high rate.
Index of Plant Concentration Increment Caused by Uptake
(Index 5)
a. Explanation - Calculates expected tissue concentra-
tion increment in plants grown in sludge-amended
soil, using uptake data for the most responsive
plant " species in the following categories: (1)
plants included in the U.S. human diet; and (2)
plants serving as animal feed. Plants used vary
according to availability of data.
b. Assumptions/Limitations - Assumes a linear uptake
slope. Neglects the effect of time; i.e., cumula-'
tive loading over several years is treated equiva-
lently to single application of the same amount.
The uptake factor chosen for the animal diet is
assumed to be representative of all crops in the
animal diet. See also Index 6 for consideration of
phytotoxicity.
c. Data Used and Rationale
i. Index of soil concentration increment (Index 1)
See Section 3, p. 3-2.
ii. Background concentration of pollutant in soil
(BS) = 100 Ug/g DW
See Section 3, p. 3-2.
3-6
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iii. Conversion factor between soil concentration
and application rate (CO) = 2 kg/ha (ug/g)"1
Assumes pollutant is distributed and retained
within upper 15 cm of soil (i.e. plow layer)
which has an approximate mass (dry matter) of
2 x 103.
iv. Uptake slope of pollutant in plant tissue (UP)
Animal diet:
Fodder rape 0.081 Ug/g tissue DW (kg/ha)'1
Human diet:
Onion 0.080 Ug/g tissue DW (kg/ha)"1
The highest uptake values for Cr in sludge were
chosen to reflect a worst-case scenario.
Uptake values for Cr VI and other compounds of
Cr are not considered analogous to Cr found in
sludge. (See Section 4, pp. 4-13 and 4-14.)
v. Background concentration in plant tissue (BP)
Animal diet:
Fodder rape 2.6 ug/g DW
Human diet:
Onion 1.1 Ug/g DW
The background concentrations in plant tissues
are the control tissue concentrations of the
same plants used for uptake values. (See
Section 4, pp. 4-13 and 4-14.)
d. Index 5 Values
Sludge Application
Rate (mt/ha)
Diet
Animal
Human
Sludge
Concentration
Typical
Worst
Typical
Worst
0
1.
1.
1.
1.
0
0
0
0
1
1
1
1
5
.0
.2
.0
.5
50
1.
3.
1.
6.
500
2
2
5
0
2.
18
4.
42a
6
8
aValue exceeds comparable value of Index 6; therefore may
be precluded by phytotoxicity.
e. Value Interpretation - Value equals factor by which
plant tissue concentration is expected to increase
above background when grown in sludge-amended soil.
3-7
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f. Preliminary Conclusion - The concentrations of Cr in
tissues of plants in the animal and human diet are
expected to increase above background levels when
sludge is landspread; these increases may be
substantial when sludge containing a high
concentration of Cr is applied at a high rate.
3. Index of Plant Concentration Increment Permitted by
Phytotoxicity (Index 6)
a. Explanation - Compares maximum plant tissue concen-
tration associated with phytotoxicity with back-
ground concentration in same plant tissue. The
purpose is to determine whether the plant concentra-
tion increments calculated in Index 5 for high
applications are truly realistic, or whether such
increases would be precluded by phytotoxicity.
b. Assumptions/Limitations - Assumes that tissue con-
centration will be a consistent indicator of phyto-
toxicity.
c. Data Used and Rationale
i. Maximum plant tissue concentration associated
with phytotoxicity (PP)
Animal diet:
Oat leaves 252 Ug/g DW
Human diet:
Onion 14 Ug/g DW
Most studies reporting tissue concentrations of
Cr associated with phytotoxicity give data for
vegetative tissue such as leaves (see Sec-
tion 4, pp. 4-11 and 4-12). Cr concentrations
may be substantial in leaves: 30 Ug/g DW was
associated with 25% reduction in yield of field
beans, and 252 Ug/g DW with 41% reduction in
oat leaves. Neither of these reductions is
great enough to preclude the possibility of
exposure of herbivorous animals to these con-
centrations as feed. Since a value for maximum
tissue concentration in fodder rape is not
available, oat leaves will be used to represent
plants in the animal diet. The only informa-
tion immediately available on the maximum tis-
sue concentrations observed in human-consumed
tissues is a statement (NAS, 1974) that concen-
trations as high as 14 Ug/g DW have been
observed in fruits, vegetables, and grain with-
out evidence of harm. Although details are
lacking and phytotoxicity was not observed, it
3-8
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will be assumed that tissue concentration in
onions will not exceed 14 Ug/g DW. (See Sec-
tion 4, p. 4-12.)
ii. Background concentration in plant tissue (BP)
Animal diet:
Oat leaves 1.0 ug/g DW
Human diet:
Onion 1.1 Ug/g DW
A background concentration for oat leaves was
not immediately available. However, data from
Section 4, p. 4-13, indicate that background
concentrations in corn and wheat leaf vary from
0.26 to 2.1 Ug/g DW. The background in fodder
rape was 2.6 Ug/g DW. Based on these values, a
concentration of 1.0 Ug/g DW is chosen for oat
leaves. The value for onion is from the same
study used in selecting an uptake value. (See
Section 4, p. 4-14.)
d. Index 6 Values
Plant Index Value
Oat leaves 252
Onion 13
e. Value Interpretation -" Value gives the maximum
factor of tissue concentration increment (above
background) which is permitted by phytotoxicity.
Value is compared with values for the same or simi-
lar plant' tissues given by Index 5. The lowest of
the two indices indicates the maximal increase which'
can occur at any given application rate.
f. Preliminary Conclusion - The substantial increases
in plant tissue concentration of Cr predicted when
high-Cr sludge is landspread at a high rate may be
precluded by phytotoxicity.
Effect on Herbivorous Animals
1. Index of Animal Toxicity Resulting from Plant Consumption
(Index 7)
a. Explanation - Compares pollutant concentrations
expected in plant tissues grown in sludge-amended
soil with food concentration shown to be toxic to
wild or domestic herbivorous animals. Does not con-
sider direct contamination of forage by adhering
sludge.
3-9
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b. Assumptions/Limitations - Assumes pollutant form
taken up by plants is equivalent in toxicity to form
used to demonstrate toxic effects in animal. Uptake
or toxicity in specific plants or animals may be
estimated from other species.
c. Data Used and Rationale
i. Index of plant concentration increment caused
by uptake (Index 5)
Index 5 values used are those for an animal
diet (see Section 3, p. 3-7).
ii. Background concentration in plant tissue (BP) =
2.6 ug/g DW
The background concentration value used is for
the plant chosen for the animal diet (see
Section 3, p. 3-7).
iii. Peed concentration toxic to herbivorous animal
(TA) = 2000 ug/g DW
Chickens ingesting feed containing 2000 Ug/g
Cr III were found to suffer reduced growth over
a 21-day study (NAS, 1980). This value was the
lowest concentration of Cr III found that
resulted in an adverse effect in animals in the
human food chain. (See Section 4, p. 4-15.)
d. Index 7 Values
Sludge Application Rate ('mt/ha)
Sludge
Concentration 0 5 50 500
Typical 0.0013 0.0013 0.0016 0.0034
Worst " 0.0013 0.0016 0.0041 0.024
e. Value Interpretation - Value equals factor by which
expected plant tissue concentration exceeds that
which is toxic to animals. Value > 1 indicates a
toxic hazard may exist for herbivorous animals.
f. Preliminary Conclusion - Landspreading of sludge is
not expected to result in plant tissue
concentrations of Cr that pose a toxic hazard to
animals consuming forage crops.
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2. Index of Animal Tozicity Resulting from Sludge Ingestion
(Index 8)
a. Explanation - Calculates the amount of pollutant in
a grazing animal's diet resulting from sludge adhe-
sion to forage or from incidental ingestion of
sludge-amended soil and compares this with the
dietary toxic threshold concentration for a grazing
animal .
b. Assumptions/Limitations - Assumes that sludge is
applied over and adheres to growing forage, or that
sludge constitutes 5 percent of dry matter in the
grazing animal's diet, and that pollutant form in
sludge is equally bioavailable and toxic as form
used to demonstrate toxic effects. Where no sludge
is applied (i.e., 0 mt/ha), assumes diet is 5 per-
cent soil as a basis for comparison.
c. Data Used and Rationale
i. Sludge concentration of pollutant (SC)
Typical 230.1 yg/g DW
Worst 1499.7 ug/g DW
See Section 3, p. 3-1.
ii. Background concentration of pollutant in soil
(BS) = 100 ug/g DW
See Section 3, p. 3-2.
iii. Fraction of animal diet assumed to be soil (GS)
Studies of sludge adhesion to growing forage
following applications of liquid or filter-cake
sludge show that when 3 to 6 mt/ha of sludge
solids is applied, clipped forage initially
consists of up to 30 percent sludge on a dry-
weight basis (Chaney and Lloyd, 1979; Boswell,
1975). However, this contamination diminishes
gradually with time and growth, and generally
is not detected in the following year's growth.
For example, where pastures amended at 16 and
32 mt/ha were grazed throughout a growing sea-
son (168 days), average sludge content of for-
age was only 2.14 and 4.75 percent,
respectively (Bertrand et al., 1981). It seems
reasonable to assume that animals may receive
long-term dietary exposure to 5 percent sludge
if maintained on a forage to which sludge is
regularly applied. This estimate of 5 percent
3-11
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sludge is used regardless of application rate,
since the above studies did not show a clear
relationship between application rate and ini-
tial contamination, and since adhesion is not
cumulative yearly because of die-back.
Studies of grazing animals indicate that soil
ingestion, ordinarily <10 percent of dry weight
of diet, may reach as high as 20 percent for
cattle and 30 percent for sheep during winter
months when forage is reduced (Thornton and
Abrams, 1983). If the soil were sludge-
amended, it is conceivable that up to 5 percent
sludge may be ingested in this manner as well.
Therefore, this value accounts for either of
these scenarios, whether forage is harvested or
grazed in the field.
iv. Feed concentration toxic to herbivorous animal
(TA) = 2000 ug/g DW
See Section 3, p. 3-10.
d. Index 8 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical 0.0025 0.0058 0.0058 0.0058
Worst 0.0025 0.038 0.038 0.0058
e. Value Interpretation - Value equals factor by which
expected dietary concentration exceeds toxic concen-
tration. Value > 1 indicates a toxic hazard may
exist for grazing animals.
f. Preliminary Conclusion - Toxicity to herbivorous
animals through direct ingestion of sludge or
sludge-amended soil is not expected to occur.
E. Effect on Humans
Index of Human Toxicity Resulting from Plant Consumption
(Index 9)
a. Explanation - Calculates dietary intake expected to
result from consumption of crops grown on sludge-
amended soil. Compares dietary intake with accept-
able daily intake (ADI) of the pollutant.
b. Assumptions/Limitations - Assumes that all crops are
grown on sludge-amended soil and that all those con-
sidered to be affected take up the pollutant at the
3-12
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same rate as the most responsive plant(s) (as chosen
in Index 5). Divides possible variations in dietary
intake into two categories: toddlers (18 months to
3 years) and individuals over 3 years old.
Data Used and Rationale
i. Index of plant concentration increment caused
by uptake (Index 5)
Index 5 values used are those for a human diet
(see Section 3, p. 3-7).
ii. Background concentration in plant tissue (BP) =
1.1 Ug/g DW
The background concentration value used is for
the plant chosen for the human diet (see
Section 3, p. 3-7).
iii. Daily human dietary intake of affected plant
tissue (DT)
Toddler 74.5 g/day
Adult 205 g/day
The intake value for adults is based on daily
intake of crop foods (excluding fruit) by vege-
tarians (Ryan et al., 1982); vegetarians were
chosen to represent the worst case. The value
for toddlers is based on the FDA Revised Total
Diet (Pennington, 1983) and food groupings
listed by the U.S. EPA (1984a). Dry weights
for individual food groups were estimated from
composition data given by the U.S. Department
of Agriculture (USDA) (1975). These values
were composited to estimated dry-weight
consumption of all non-fruit crops.
iv. Average daily human dietary intake of pollutant
(DI)
Toddler 22 ug/day
Adult 65 Ug/day
The adult value is the average of Cr in three
diet studies reported by MAS (1974). No value
was reported for toddlers. The value for
toddlers is assumed to be 1/3 the value of
adults. (See Section 4, p. 4-5.)
3-13
-------
v. Acceptable daily intake of pollutant (ADI) =
111,000 Ug/day
An ADI of 111,000 Jig/day was derived by the
U.S. EPA (1984b) based on the highest no-
observed-adverse-effects level (NOAEL) in a
study on rats fed a diet containing Cr III. An
uncertainty factor of 1000 was applied in cal-
culating the human ADI. (See Section 4,
p. 4-6.)
d. Index 9 Values
Sludge
Group Concentration
0
Sludge Application
Rate (mt/ha)
5 50 500
Toddler Typical
Worst
Adult
Typical
Worst
0.00020 0.00023 0.00054 0.0030
0.00020 0.00057 0.0038 0.0303
0.00058 0.00068 0.0015 0.0083
0.00058 0.0016 0.011 0.083s
f.
aValue may be precluded by phytotoxicity; see
Indices 5 and 6.
Value Interpretation - Value equals factor by which
expected intake exceeds ADI. Value > 1 indicates a
possible human health threat. Comparison with the
null index value at 0 mt/ha indicates the degree to
which any hazard is due to sludge application, as
opposed to pre-existing dietary sources.
Preliminary Conclusion - Human intake of Cr through
the consumption of plants grown in sludge-amended
soil is not expected to pose a health threat.
2. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Feeding on Plants
(Index 10)
a. Explanation - Calculates human dietary intake
expected to result from consumption of animal
products derived from domestic animals given feed
grown on sludge-amended soil (crop or pasture land)
but not directly contaminated by adhering sludge.
Compares expected intake with ADI.
b. Assumptions/Limitations - Assumes that all animal
products are from animals receiving all their feed
from sludge-amended soil. The uptake slope of pol-
lutant in animal tissue (UA) used is assumed to be
3-14
-------
representative of all animal tissue comprised by the
daily human dietary intake (DA) used. Divides pos-
sible variations in dietary intake into two categor-
ies: toddlers (18 months to 3 years) and
individuals over 3 years old.
Data Used and Rationale
i. Index of plant concentration increment caused
by uptake (Index 5)
Index 5 values used are those for an animal
diet (see Section 3, p. 3-7).
ii. Background concentration in plant tissue (BP) =
2.6 ug/g DW
The background concentration value used is for
the plant chosen for the animal diet (see
Section 3, p. 3-7).
iii. Uptake slope of pollutant in animal tissue (UA)
= 0 Mg/g tissue DW (ug/g feed DW)'1
In the only study immediately available from
which uptake slopes could be calculated for
consumed animal tissue, beef steers grazed on
sludge-amended pasture did not take up Cr in
kidney, liver, or muscle in spite of a 3-fold
increase in dietary Cr (Bertrand et aL., 1981).
(See Section 4, p. 4-17.)
iv. Daily human dietary intake of affected animal
tissue (DA)
Toddler 51.1 g/day
Adult 133 g/day
The intake values presented which comprise
meat, fish, poultry and eggs are derived from
the FDA Revised Total Diet (Pennington, 1983),
food groupings listed by U.S. EPA (1984a), and
food consumption data listed by USDA (1975).
Adult intake of meats is based on males 25 to
30 years of age, the age-sex group with the
highest daily intake (Pennington, 1983).
v. Average daily human dietary intake of pollutant
(DI)
Toddler 22 Ug/day
Adult 65 Ug/day
See Section 3, p. 3-13.
3-15
-------
vi. Acceptable daily intake of pollutant (ADI) =
111,000 ug/day
See Section 3, p. 3-14.
d. Index 10 Values
Sludge Application
Rate (mt/ha)
Sludge
Group Concentration 0 5 50 500
Toddler Typical 0.00020 0.00020 0.00020 0.00020
Worst 0.00020 0.00020 0.00020 0.00020
Adult Typical 0.00058 0.00058 0.00058 0.00058
Worst 0.00058 0.00058 0.00058 0.00058
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - A health threat due to Cr
is not expected for humans who consume animal
products derived from animals feeding on plants
grown in sludge-amended soil.
3. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Ingesting Soil
(Index 11)
a. Explanation - Calculates human dietary intake
expected to result from consumption of animal prod-
ucts derived from grazing animals incidentally
ingesting sludge-amended soil. Compares expected
intake with ADI.
b. Assumptions/Limitations - Assumes that all animal
products are from animals grazing sludge-amended
soil, and that all animal products consumed take up
the pollutant at the highest rate observed for
muscle of any commonly consumed species or at the
rate observed for beef liver or dairy products
(whichever is higher). Divides possible variations
in dietary intake into two categories: toddlers
(18 months to 3 years) and individuals over three
years old.
c. Data Used and Rationale
i. Animal tissue = Beef muscle
See Section 3, p. 3-15.
3-16
-------
ii. Background concentration of pollutant in soil
(BS) = 100 jag/g DW
See Section 3, p. 3-2.
iii. Sludge concentration of pollutant (SC)
Typical 230.1 Ug/g DW
Worst 1499.7 ug/g DW
See Section 3, p. 3-1.
iv. Fraction of animal diet assumed to be soil (GS)
= 5%
See Section 3, p. 3-11.
v. Uptake slope of pollutant in animal tissue_jLUA)
= 0 Ug/g tissue DW (ug/g feed DW)~1
See Section 3, p. 3-15.
vi. Daily human dietary intake of affected animal
tissue (DA)
Toddler 51.1 g/day
Adult 133 g/day
See Section 3, p. 3-15.
vii. Average daily human dietary intake of pollutant
(DI)
Toddler 22 Ug/day
Adult 65 Ug/day
See Section 3, p. 3-13.
viii. Acceptable daily intake of pollutant (ADI) =
111,000 Ug/day
See Section 3, p. 3-14.
3-17
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d. Index 11 Values
Sludge Application
Rate (mt/ha)
Sludge
Group Concentration 0 5 50 500
Toddler Typical 0.00020 0.00020 0.00020 0.00020
Worst 0.00020 0.00020 0.00020 0.00020
Adult Typical 0.00058 0.00058 0.00058 0.00058
Worst 0.00058 0.00058 0.00058 0.00058
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - Human intake of Cr through
consumption of animal products derived from animals
which have ingested sludge-amended soil or pure
sludge, is not expected to pose a health threat.
A. Index of Human Toxicity from Soil Ingestion (Index 12)
a. Explanation - Calculates the amount of pollutant in
the diet of a child who ingests soil (pica child)
amended with sludge. Compares this amount with RSI.
b. Assumptions/Limitations - Assumes that the pica
child consumes an average of 5 g/day of sludge-
amended soil. If an ADI for a child is not
available, this index assumes that the ADI for a
10 kg child is the same as that for a 70 kg adult.
It is thus assumed that uncertainty factors used in
deriving the ADI provide protection for the child,
taking into account the smaller body size and any
other differences in sensitivity.
c. Data Used and Rationale
i. Index of soil concentration increment (Index 1)
See Section 3, p. 3-2.
ii. Sludge concentration of pollutant (SC)
Typical 230.1 ug/g DW
Worst 1499.7 Ug/g DW
See Section 3, p. 3-1.
iii. Background concentration of pollutant in soil
(BS) = 100 ug/g DW
See Section 3, p. 3-2.
3-18
-------
d.
Group
iv. Assumed amount of soil in human diet (DS)
Pica child 5 g/day
Adult 0.02 g/day
The value of 5 g/day for a pica child is a
worst-case estimate employed by U.S. EPA's
Exposure Assessment Group (U.S. EPA, 1983a).
The value of 0.02 g/day for an adult is an
estimate from U.S. EPA (1984a).
v. Average daily human dietary intake of pollutant
(DI)
Toddler 22 ug/day
Adult 65 ug/day
See Section 3, p. 3-13.
vi. Acceptable daily intake of pollutant (ADI) =
111,000 Ug/day
See Section 3, p. 3-14.
Index 12 Values
Sludge
Concentration
Sludge Application
Rate (mt/ha)
5 50
Pure
500 Sludge
Toddler Typical 0.0047 0.0047 0.0048 0.0059 0.011
Worst 0.0047 0.0048 0.0062 0.017 0.068
Adult Typical 0.00060 0.00060 0.00060 0.00061 0.00063
Worst 0.00060 0.00060 0.00061 0.00065 0.00086
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - The direct ingestion of
sludge-amended soil or pure sludge by humans is not
expected to pose a health threat due to Cr.
5. Index of Aggregate Human Toxicity (Index 13)
a. Explanation - Calculates the aggregate amount of
pollutant in the human diet resulting from pathways
described in Indices 9 to 12. Compares this amount
with ADI.
b. Assumptions/Limitations - As described for Indices 9
to 12.
3-19
-------
Data Used and Rationale - As described for Indices 9
to 12.
d. Index 13 Values
Sludge
Group Concentration
Sludge Application
Rate (mt/ha)
5 50 500
Toddler Typical
Worst
Adult Typical
Worst
0.0047 0.0047 0.0052 0.0087
0.0047 0.0047 0.0099 0.0473
0.00060 0.00070 0.0015 0.0083
0.00060 0.0016 0.011 0.083a
e.
f.
II. LANDFILLIMG
aValue may be partially precluded by phytotoxicity;
see Indices 9 and 18.
Value Interpretation - Same as for Index 9.
Preliminary Conclusion - The aggregate amount of Cr
in the human diet resulting from landspreading of
sludge is not expected to pose a health threat.
A. Index of Groundwater Concentration Increment 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 Exposure Assessment Group (EAG)
model, "Rapid Assessment of Potential Groundwater Contam-
ination Under -Emergency Response Conditions" (U.S. EPA,
1983b). 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 concentra-
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
3-20
-------
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
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; 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., K
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).
3-21
-------
(c) Volumetric water content (8)
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
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.
ii. Site parameters
(a) Landfill leaching time (LT) = 5 years
Sikora et al. (1982) monitored several
landfills throughout the United States and
estimated time of landfill leaching to be 4 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 m/year
Worst 1.6 m/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
complete in 5 years. Landfilled sludge is
assumed to be 20 percent solids by volume, and
' depth of sludge in the landfill is 5 m in the
typical case and 10 m in the worst case. Thus,
the initial depth of liquid is 4 and 8 m, and
average yearly leachate generation is 0.8 and
1.6 m, respectively.
(c) Depth to groundwater (h)
r
Typical 5 m
Worst 0 m
Eight landfills were monitored throughout the
United States and depths to groundwater below
them were listed. A typical depth of ground-
3-22
-------
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 groundwater.
(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 (Gelhar and Axness, 1981). Thus,
based on depth to groundwater listed above, the
value for the typical case is 0.5 and that 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 230.1 mg/kg DW
Worst 1499.7 mg/kg DW
See Section 3, p. 3-1.
(b) Degradation rate (u) = 0 day"1
The degradation rate in the unsaturated zone is
assumed to be zero for all inorganic chemicals
(c) Soil sorption coefficient
Typical 56.5 mL/g
Worst 16.8 mL/g
K^ values were obtained from Gerritse et al.
(1982) using sandy loam soil (typical) or sandy
soil (worst). Values shown are geometric means
of a range of values derived using sewage
sludge solution phases as the liquid phase in
the adsorption experiments.
3-23
-------
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 and with less dispersion and
therefore represents a reasonable worst case.
(b) Aquifer porosity (0)
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 at al. (1982) as presented
in U.S. EPA (1983b).
(c) Hydraulic conductivity of the aquifer (K)
Typical 0.86 m/day
Worst 4.04 m/day
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 (1983b).
ii. Site parameters
(a) Average hydraulic gradient between landfill and
well (i)
Typical 0.001 (unitless)
Worst 0.02 (unitless)
3-24
-------
The hydraulic gradient is the slope of the
water table in 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 (A!)
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 (AH), which is 100 and
50 m, respectively, for typical and worst
conditions.
(d) Minimum thickness of saturated zone (B) = 2 m
The minimum aquifer thickness represents 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 nr.
iii. Chemical-specific parameters
(a) Degradation rate (u) = 0 day"1
Degradation is assumed not to occur in the
saturated zone.
3-25
-------
(b) Background concentration of pollutant in
groundwater (BC) = 6.5 pg/L
A median value, 6.5 Ug/L» of the range (0 to
13 Ug/L) of well water concentrations in
California was chosen as a conservative value
from the standpoint of human toxicity (U.S.
EPA, 1983c). (See Section 4, p. 4-3.)
(c) Soil sorption coefficient (Kj) = 0 mL/g
Adsorption is assumed to be zero in the
saturated zone.
4. Index Values - See Table 3-1.
5. Value Interpretation - Value equals factor by which
expected groundwater concentration of pollutant at well
exceeds the background concentration (a value of 2.0
indicates the concentration is doubled, a value of 1.0
indicates no change).
6. Preliminary Conclusion Groundwater concentrations of Cr
at the well are expected to increase above background
concentrations when sludge is landfilled; this increase
may be substantial at a disposal site with all worst-case
conditions.
B. Index of Human Toxicity Resulting from Groundwater
Contamination (Index 2)
1. Explanation - Calculates human exposure which could
result from groundwater contamination. Compares exposure
with acceptable daily intake (ADI) of pollutant.
2. Assumptions/Limitations - Assumes long-term exposure to
maximum concentration at well at a rate of 2 L/day.
3. Data Used and Rationale
a. Index of groundwater concentration increment result-
ing from landfilled sludge (Index 1)
See Table 3-1.
b. Background concentration of pollutant in groundwater
(BC) = 6.5 pg/L
See Section 3, p. 3-26.
3-26
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Site Characteristics 1
Sludge concentration T
Unsaturated Zone
Soil type and charac- T
teristics"
Site parameters6 T
Saturated Zone
Soil type and charac- T
teristics^
u Site parameters^ T
i
tv)
^ Index 1 Value 2.0
Index 2 Value 0.00070
Condition of Analysisa»P»c
2345 6
W T T T T
T W NA T T
T T W T T
T T T W T
T T T T W
7.3 2.0 2.0 6.1 37
0.0013 0.00070 0.00070 0.0012 0.0048
7 8
W N
NA N
W N
W N
W N
1300 0
0.157 0.00058
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.
^Index values for combinations other than those shown may be calculated using the formulae in the Appendix.
cSee Table A-l in Appendix for parameter values used.
^Dry bulk density (Pdry) and volumetric water content (6).
eLeachate generation rate (Q), depth to groundwater (h), and dispersivity coefficient (a).
^Aquifer porosity (0) and hydraulic conductivity of the aquifer (K).
SHydraulic gradient (i), distance from well to landfill (AH), and dispersivity coefficient (o).
-------
c. Average human 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.
d. Average daily human dietary intake of pollutant (DI)
= 65 Ug/day
See Section 3, p. 3-13.
e. Acceptable daily intake of pollutant (ADI) =
111,000 Ug/day
See Section 3, p. 3-14.
4. Index 2 Values - See Table 3-1.
5. Value Interpretation - Value equals factor by which
pollutant intake exceeds ADI. Value >1 indicates a
possible human health threat. Comparison with the null
index value indicates the degree to which any hazard is
due to landfill disposal, as opposed to preexisting
dietary sources.
6. Preliminary Conclusion - Groundwater contamination
produced by landfilled sludge is not expected to pose a
human health threat due to Cr.
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,
1979a). 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.
3-28
-------
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 10~7 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 rate 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:
EP = 360 Ib H20/mm BTU
Combustion zone temperature - 1400°F
Solids content - 28%
Stack height - 20 m
Exit gas velocity - 20 m/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 Ib H20/mm BTU
Combustion zone temperature - 1400°F
Solids content - 26.62 y
Stack height - 10 m
Exit gas velocity - 10 m/s
Exit gas temperature - 313.8°K (105°F)
Stack diameter - 0.80 m
c. Sludge concentration of pollutant (SC)
Typical 230.1 mg/kg DW
Worst 1499-7 mg/kg DW
See Section 3, p. 3-1.
d. Fraction of pollutant emitted through stack (FM)
Typical 0.003 (unitless)
Worst 0.006 (unitless)
3-29
-------
Emission estimates may vary considerably between
sources; therefore, the values used are based on a
U.S. EPA 10-city incineration study (Farrell and
Wall, 1981). Where data were not available from the
EPA study, a more recent report which thoroughly
researched heavy metal emissions was utilized (CDM,
1983).
e. Dispersion parameter for estimating maximum annual
ground level concentration (DP)
Typical 3.4 Ug/m3
Worst 16.0 Ug/m3
The dispersion parameter is derived from the U.S.
EPA-ISCLT short-stack model.
f. Background concentration of pollutant in urban
air (BA) = 0.010 ug/m3
The U.S. EPA (1978) reported that yearly averages of
greater than 0.010 Ug/m3 occurred in only 59 of 186
urban areas. From the data immediately available,
0.010 Ug/ro^ represents a conservative value from the
standpoint of human toxicity. (See Section 4,
p. 4-4.)
Index 1 Values
Sludge Feed
Fraction of ' Rate (kg/hr DW)a
^Pollutant Emitted Sludge
Through Stack Concentration 0 2660 10,000
Typical
Typical
Worst
1.0
1.0
1.2
2.1
4.1
21.0
Worst Typical 1.0 1.3 7.1
Worst 1.0 3.3 41.0
aThe typical (3.4 Ug/m3) and worst (16.0 Ug/m3) 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
expected to increase air concentrations of Cr above
background levels; this increase may be substantial when
sludge containing a high concentration of Cr is
incinerated at a high feed rate.
3-30
-------
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 10"^.
2. Assumptions/Limitations - The exposed population is
assumed to reside within the impacted area for 24
hours/day. A respiratory volume of 20 m3/day is assumed
over a 70-year lifetime.
3. Data Used and Rationale
a. Index of air concentration increment resulting from
incinerator emissions (Index 1)
See Section 3, p. 3-30.
b. Background concentration of pollutant in urban air
(BA) = 0.010 Ug/m3
See Section 3, p. 3-30.
c. Cancer potency =41 (mg/kg/day)^
The Carcinogen Assessment Group (CAG) of U.S. EPA
has carried out a quantitative assessment of cancer
risk for inhaled Cr. Although this risk estimate is
not specific as to the form inhaled, the estimate
"is to be used only in conjunction with those Cr
compounds evaluated by the CAG to be carcinogenic";
that is hexavalent Cr compounds (U.S. EPA, 1983c).
Cr in incinerator emissions is assumed to be in the
hexavalent form due to the high temperatures in the
combustion chamber. This assumption constitutes a
conservative approach where definitive data are
lacking. Therefore, Cr emissions from sludge incin-
erators are assumed to be carcinogenic. Based on a
value of 1.7 x 10~6 mg/day established by the U.S.
EPA (1980), a- cancer potency of 41 (mg/kg/day)"1 was
derived by adjusting to continual inhalation
exposure (U.S. EPA, 1983c).
d. Exposure criterion (EC) = 8.5 x 10"^ ug/m3
A lifetime exposure level which would result in a
10~° cancer risk was selected as ground level
concentration against which incinerator emissions
are compared. The risk estimates developed by CAG
3-31
-------
are defined as the lifetime incremental cancer risk
in a hypothetical population exposed continuously
throughout their lifetime to the stated
concentration of the carcinogenic agent. The
exposure criterion is calculated using the following
formula:
c-r - 10"6 x 103 ug/mg x 70 kg
£U - - r~
Cancer potency x 20 mj/day
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 120 140 480
Worst 120 ' 250 2500
Worst Typical 120 160 840
Worst 120 380 4800
aThe typical (3.4 lig/m) and worst (16.0 Ug/m-) 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 > 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 - Inhalation of emissions from
sludge incineration is expected to increase the human
cancer risk due to Cr above the risk posed by background
urban air concentrations of Cr. This increase in cancer
risk may be substantial when high-Cr sludge is
incinerated at a high feed rate.
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWES 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.
3-32
-------
SECTION 4
PRELIMINARY DATA PROFILE FOR CHROMIUM IN MUNICIPAL SEWAGE SLUDGE
I. OCCURRENCE
A. Sludge
1. Frequency of Detection
Assumed 100% because of the ubiquitous
nature of Cr
2. Concentration
Range 22 to 33,000 pg/g DW
Mean 2031 Ug/g DW
Median 380 Ug/g DW
Median 230.1 Ug/g DW
95th percentile 1499.7 ug/g DW
Median 1320 ug/g DW
95% 14,000 ug/g DW
94% 4925 ug/g DW
Chicago, XL
4200 ug/g DW
Southern CA
<40 to 600 ug/g DW
Oklahoma
trace levels to 600 ug/g DW
Indiana
50 to 19,600 Ug/g DW
Incinerated sludge ash 5280 ug/g
B. Soil - Unpolluted
1. Frequency of Detection
Virtually 100%
Page, 1974
(p. 11)
Values statis-
tically
derived from
sludge concen-
tration data
presented in
U.S. EPA, 1982
Furr et al.,
1976a (p. 684)
Page, 1974
(p. 15)
U.S. EPA,
1983c
(p. 3-29)
4-1
-------
2. Concentration
64% of U.S. soils in 25 to 85 ppm range
Most soils <300 ppm
Median 100 ppm
Range 5 to 3000 ppm
5 to 1500 ppm
Mean 43 ppm {Canadian soils)
U.S. Soils
Range 1 to 1000 ppm
Selected U.S. median concentrations!
14 to 70 ppm
Missouri - Median 71 ppm
Natural soils
Range 5 to 3000 ppm
Mean 40 ppm
10 to 6000 kg/ha
Typical level 200 kg/ha
Minnesota soils
Range 14 to 111 Ug/g
Median 36" ug/g
Mean 43 ug/g
5.0 to 1000 ppm
C. Water - Unpolluted
1. Frequency of Detection
386 of 1577
2. Concentration
a. Freshwater
Range 0.1 to 6 ppb
Median 1 ppb
U.S. EPA, 1978
(p. 226)
U.S. EPA, 1978
(p. 226)
Allaway, 1968
(p. 241)
Gary, 1982
(p. 51)
Gary, 1982
(p. 51)
U.S. EPA, 1983c
(p. 3-30)
U.S. EPA, 1983c
NAS, 1974
(p. 85)
Page, 1974
(p. 71)
Pierce et al.,
L982 (p. 418)
Yopp et al.,
1974 (p. 89)
Page, 1974
(p. 25)
Gary, 1982
(p. 53)
4-2
-------
North American rivers:
58 yg/L
Range 0 to 112 ppb
Average 9.7 ppb
Range 1 to 112
U.S. surface water mean con-
centration (based on 1577
samples) 9.7 Ug/L
b. Seawater
Mean 0.3 ppb
Range 0.2 to 50 ppb
0.5
0.04 to 0.07 ppb
Surface seawater
0.02 to 0.14 ppb Cr III
0.28 to 0.36 ppb Cr VI
Drinking Water
Range 0 to 79 ppb
Average 2.3 ppb
Maximum permissible Cr
concentration in public water
supplies 0.05 ppm
Tap water (3834 U.S. cities)
0.4 to 8 ppb
0,43 Ug/L as Cr
Average 10 Ug/L
Groundwater
<10 ug/L uncontaminated
well (New York);
0 to 13 Ug/L well water
(California); 5 to 38 Ug/L
in Illinois River
600 Ug/L contaminated well
(Mew York.)
Hem, 1970
U.S. EPA, 1978
U.S. EPA, 1980
U.S. EPA, 1980
(p. A-2)
Gary, 1982
(p. 53)
Hem, 1970
(p. 11)
U.S. EPA,
1978 (p. 236)
U.S. EPA,
1978 (p. 240)
U.S. EPA,
1978 (p. 236)
U.S. EPA,
1978 (p. 247)
U.S. EPA,
1983c
(p. 2-2)
Hem, 1970
U.S. EPA,
1980
(p. C-6)
U.S. EPA,
1983c (p. 3-25)
4-3
-------
D. Air
1. Frequency of Detection
Most is in the form of particulate
in the atmosphere
Ambient air concentration
1.785 x 10~2 ug/m3 Cr III
Urban-rural range
0.0052 to 0.1568 Ug/m3
Traces to 0.02 Ug/m3 as Cr
No naturally occurring gaseous forms.
However, Cr is associated with
particulate matter or aerosol mist
(as in plating or cooling towers).
National Air Sampling Network 1964 gave
a national average of 0.015 Ug/m3
with maximum of 0.350 Ug/m3
2.
Concentration
Urban
Yearly averages
Ranges = below detection level to
0.120 Ug/m3
Only 59 of 186 urban cities
exceeded 0.010 Ug/ro3
yearly'averages
Rural
Usually below detection limits
Mean of 5.3 + 3.0 pg/m3 at
South Pole with a range of 2.5
to 10 pg/m3
B. Pood
1. Total Average Intake
50 to 100 Ug/day
100 to 280
U.S. EPA,
1978 (p. 3)
ACGIH, 1983
U.S. EPA,
1983c (p. 2-2)
NAS, 1974
(p. 85)
Gary, 1982
(p. 55)
U.S. EPA,
1979b (p. 213)
U.S. EPA,
1978 (p. 267)
U.S. EPA,
1980 (p. C-8)
U.S. EPA,
1978
(p. 225)
U.S. EPA,
1980 (p. C-6)
NAS, 1974
4-4
-------
5 to 115 Ug/day in food
78 Ug/day institutional diet
52 lag/day institutional diet
78 yg/day institutional diet
65 yg/day student diet
Total all media intake = 100 yg/day/
individual; 80 yg from food
2. Concentration
Cherry/fruit 0.032 ppra DW
Corn/grain 0.48 ppm DW
Pear/whole fruit 0.03 ppm DW
Potato/tuber 0.002 ppm DW
Pear/whole fruit 0.44 mg/kg
Potato 0.15 mg/kg
Average for all foods 0.175 to
0.472 mg/kg institutional diet
80 yg/day Cr intake/individual
II. HUMAN EFFECTS
A. Ingestion
1. Carcinogenicity
a. Qualitative Assessment
The oral Carcinogenicity of Cr VI
and Cr III has never been
demonstrated.
Existing oral Carcinogenicity data
for Cr III is negative and recent
data indicate that in the presence
of gastric juice, Cr VI is reduced
to Cr III.
0.5 mg/m-* threshold limit value
Cr III
b. Potency
Not applicable.
c. Effects
Not applicable.
U.S. EPA,
1978 (p. 165)
NAS, 1974
(p. 28)
U.S. EPA,
1978 (p. 267)
U.S. EPA,
1978 (p. 84)
U.S. EPA,
1978
(pp. 265 to
(267)
U.S. EPA,
1980 (p. C-32)
U.S. EPA,
1980 (p. C-33)
ACGIH, 1983 in
U.S. EPA,
1984b
4-5
-------
2. Chronic Toxicity
a. ADI
Cr VI = 0.175 mg/day/man
b.
Cr III
Effects
= 111 mg/day/man
Hypersensitivity, respiratory
effects.
3. Absorption Factor
<12 Cr*3
3 to 6% Cr+6
0.1% to 1.2% trivalent Cr salts
absorbed
4. Existing Regulations
Domestic water supply 50 Ug/L total Cr
Drinking water 50 yg/L total Cr VI
Livestock water 1000 Ug/L Cr VI
Ambient water quality criteria for
protection of human health
59,000 pg/L Cr III
83 Ug/L Cr VI
B. Inhalation
1. Carcinogenic!ty
a. Qualitative Assessment
Using the IARC classification
scheme, Cr falls in Group 1,
meaning there is decisive evi-
dence for carcinogenicity in
humans.
It is presumed that all forms
of Cr VI are carcinogenic;
Cr III is less studied but is
considered less likely to be
carcinogenic.
U.S. EPA, 1980
(p. C-34)
U.S. EPA,
1984b
U.S. EPA,
1984b
Tandon, 1982
(p. 218)
U.S. EPA,
1978 (p. 143)
U.S. EPA, 1980
(p. C-31)
U.S. EPA,
1983c (p. 8-4)
U.S. EPA,
1983c
(p. 7-84)
4-6
-------
Potency
Cr VI (lung cancer) cancer potency
= 41 (mg/kg/day)'1
CAG estimated lifetime cancer risk
due to constant exposure to air
containing 1 jag/m^ of
hexavalent Cr to be 1.2 x 10~2
Cancer potency = 41 (mg/kg/day)~^
Effects
Lung tumors in chromate industry
workers
Mutagenicity - mutagenic and cell
transforming of chromates
Chronic Toxicity
a. Inhalation Threshold or MPIH
Cr VI oral 50 Ug/L total Cr
0.175 mg/day/man ADI
b. Effects
Respiratory effects, hyper-
sensitivity.
Absorption Factor
Airborne Cr exposure 0.2 ug/day for
each individual
Existing Regulations
NIOSH 1 ug/m3 Cr VI recommended
maximum workplace concentration
airborne
NIOSH 1 Ug/m3 Cr VI (insoluble)
is carcinogenic
25 Ug/m3 Cr III noncarcino-
genic (soluble); time weighted
U.S. EPA,
1983c
U.S. EPA,
1983c (p.
2-9)
U.S. EPA,
1983c (p.
7-79)
U.S. EPA,
1983c (p.
2-9)
U.S. EPA,
1980
(p. C-22)
U.S. EPA,
1980
U.S. EPA,
1978 (p. 267)
U.S. EPA,
1978
(p. 188)
U.S. EPA,
1978 (p. 188)
4-7
-------
average exposure, 10-hr workday,
40-hr workweek
50 Ug/m^ Cr III noncarcino-
genic; 15-min. sample
Permissible maximum concentration
Chromic and chromous salts 0.5 mg/nH
Metal and soluble salts 1.0 mg/nH
III. PLANT EFFECTS
A. Phytotoxicity
See Table 4-1.
Moderately toxic
B. Uptake
See Table 4-2.
Plant background concentration
0.2 to 1.0 pg/g
IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS
A. Toxicity
3000 ppm Cr as an oxide in cattle and sheep
feed (NOAEL)
1000 ppm Cr as a chloride in chickens (NOEL)
100 ppm Cr as K2Cr°4 or Na2CrC>4 in chicks
(NOAEL)
See Table 4-3.'
B. Uptake
See Table 4-4.
V. AQUATIC LIFE EFFECTS
A. Toxicity
1. Freshwater
Freshwater aquatic organisms should
not be affected unacceptably if the
four-day average concentration of
acid-soluble Cr VI does not exceed
11 Ug/L more than once every three
years on the average and if the one-
U.S. EPA,
1980
(p. C-31)
Allaway, 1968
(p. 241)
Allaway, 1968
(p. 241)
Allaway, 1968
(p. 241)
NAS, 1980
(p. 147)
U.S. EPA, 1985
4-8
-------
hour average concentration does not
exceed 16 Ug/L more than once
every three years on the average.
Freshwater aquatic organisms should
not be affected unacceptably if at
water hardnesses of 50, 100, and
200 mg/L as CaC03, the four-day
average concentrations of acid-
soluble Cr III do not exceed
120, 210, and 370 Ug/L, respectively,
and the one-hour average concentrations
do not exceed 980, 1700, and
3100 Ug/L, respectively.
2. Saltwater
No saltwater criterion can be derived U.S. EPA, 1985
for Cr III, but 10,300 ug/L is the
EC50 for eastern oyster embryos, whereas
50,400 Ug/L did not affect a poly-
chaete worm in a life-cycle test.
B. Uptake
Passive uptake in rainbow trout U.S. EPA, 1978
(p. 109)
Bioconcentration Factor (BCF) U.S. EPA, 1980
(p. C-7)
Cr VI in fish muscle <1
Blue mussel 192
Oyster 125
Cr III Soft shell clam 153
Blue mussel 86
Oyster 116
Weighted average BCF for edible portions U.S. EPA, 1980
of all freshwater and estuarine aquatic (p. C-8)
organisms = 16
VI. SOIL BIOTA EFFECTS
Data not immediately available.
4-9
-------
VII. PHYSICOCHEMICAL DATA FOR ESTIMATING PATE AND TRANSPORT
Atomic weight: 51.996 CRC Handbook of
Melting point: 1857 + 20°C Chemistry and
Boiling point: 2672°C Physics,
64 Ed. (p. B85)
Cr is slightly soluble in dilute
H2S04 or dilute HC1 but is
insoluble in water.
Soil partition coefficient (K,j) mL/g
Sandy soil 16.8 Gerritse
Sandy loam soil 56.5 et al., 1982
(p. 359 to 364)
4-10
-------
TABLE 4-1. PHYTOTOXICITY OF CHROMIUM
Plant/tissue
Soybeans
Soybeans/ tops
Soybeans/ roots
Bean/leaf
Bean/root
Corn
Corn
Oats
Field Bean/leaf
Tomato/leaf
Corn/leaf
Chemical
Form Applied
Cr VI
Cr VI
Cr VI
Cr VI
Cr VI
Cr VI
Cr VI
-sludge (pot)
Cr VI
-sludge (pot)
Cr III
Cr2(SO«)3
-sludge
Cr VI
Cr VI
Crb
Crb
Sludge (field)
Soil
pU
NRC
NR
NR
NR
NR
NR
NR
NR
5.5
NR
NR
NR
NR
NR
Control
Tissue
Concentration
(ug/g DW)
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
0.4
Experimental
Soil
Concentrat iona
(Ug/g DW)
0-5
0.5
1.0
0.01
0.1-1
0.2
80
320
320
5
10
200
NR
NR
Experimental
Application
Rate
(kg/ha)
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
135, 270, 530
Experimental
Tissue
Concentration
(ug/g DW)
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
30
5
0.4, 0.4, 0.5
Effect References
Decreased uptake U.S. EPA, 1978
of nutrients (p. 97)
Decreased growth
Decreased growth
Dry weight reduction
Chlorosis; greatest
weight reduction
Decrease in dry weight
87Z weight decrease
97Z weight decrease
50Z reduced yield
Diffuse leaf chlorosis
Chlorotic and stunted
25Z reduction in CAST, 1976
yield (p. 25 and 46)
Yield reduction
No increase cone.
Corn/grain
(anaerobic)
Sludge (field) NR
(anaerobic)
NR
135, 270, 530 <0.1
due to application
rate
No increase cone.
due to application
rate
-------
TABLE 4-1 (continued)
NJ
Chemical Soil
Plant/tissue Form Applied pit
Corn/leaf
Corn/leaf
Corn/stover
Plants
Corn
Tobacco/leaves
Tobacco/roots
Corn/leaves
Pruits, vegetables,
grain
Oat/leaves
Soybean/leaves
Corn/leaves
Sludge (field)
Sludge (field)
Sludge (field
Cr VI
Chromic sulfate
Natural
high-Cr soil
same as above
same as above
Cr°
Natural
high-Cr soil
Cr&
CrD
Cr°
Crb
Cr°
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Control
Tissue
Concentration
(Ug/g DW)
1 . 2 ppm
1.5
1.0
1.1-1.9
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Experimental Experimental
Soil Application
Concentration8 Rate
(Ug/g DW) (kg/ha)
NR
NR
NR
8.4-71
5
NR
NR
NR
NR
NR
NR
NR
NH
NR
NR
NR
350-700
416-833
416-833
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Experimental
Tissue
Concentration
(MB/g DW) Effect
1.3-1.2
1.2
1.2
-------
TABLE 4-2. UPTAKE Of CHROMIUM BY PLANTS
Plant/tissue
Corn/tops
Corn/leaf
Corn/leaf
Corn/tops
Wheat/grain
Wheat /stem
Wheat/leaf
Alfalfa
Buckwheat /whole
plant
Swiss chard
Potato/cortex
Potato/cortex
Fodder rape
Chemical Form
Applied
Sludge (A) (pot)
Sludge (B) (pot)
Sludge & Na2Cr207(CrVI)
Sludge & Na2Cr207(CrVI)
Sludge & Cr2(S04)3(CrIII
Sludge (field)
Sludge (field)
Sludge (field)
(anaerobic)
Sludge (pot)
(anaerobic-amended)
Cr(OH)3 (CrllD(pot)
Cr(OH)3 (CrlllHpot)
CR(Otl)3 (CrllD(pot)
Cr(OH)3 (CrllD(pot)
Cr(OH)3 (CrllD(pot)
Sludge (field)
(anaerobic)
Sludge (field)
(liquid)
Sludge (field)
(anaerobically digested,
Sludge
Soil
pll
NRC
NR
5.5
7.0
) 5.5
NR
NR
NR
6.8
5.6
5.6
5.6
5.6
5.6
5.5 - 6.5
4.5 - 4.9
NR
liquid)
NR
Range (and Nfl) of
Application Rates
(kg/ha)
68-1360 ppm
3-50 ppm
5-320
5-320
5.320
0-700
0-B33
0-530 (4)
0-3340 (4)
0-12,000 (6)d
0-12,000 (6)d
0-12,000 (6)d
0-12,000 (6)d
0-12,000 (6)d
0-282 (2)
0-0.28 (2)
0-605 (2)
0-18.5 (2)
Control Tissue
Concentration,
(ug/g DU)
2.1
2.1
1.6
0.5
1.6
1.2
1.5
0.4
<3.0
0.011
0.029
0.258
0.101
0.211
1.0
1.0
1.36
2.6
Uptake*3
Slope
-4.15 x 10-4
-0.0195
0.171
0.178
0.00431
0
NR
0.000193
0.010
0.15 x 10~6
12 x 10'6
39 x 10'6
10 x 10~6
26 x 10~6
0.0004
0.0
0.0014
0.081
References
U.S. EPA, 1978 (p. 76)
CAST, 1976 (p. 47)
CAST, 1976 (p. 46)
Cunningham et al., 1975
Carey, 1982 (p. 58)
Furr et al., 1976a
(p. 87)
Naylor and Mondy, 1984
(p. 9)
Page, 1974 (p. 45)
-------
Table 4-2. (continued)
Plant/tissue
Bean/edible
Cabbage/edible
Carrot/edible
Millet/edible
Onion/edible
Potato/edible
Tomato/edible
Chemical form
Applied
Sludge (pot)
(air dried)
Sludge (pot)
(air dried)
Sludge (pot)
(air dried)
Sludge (pot)
(air dried)
Sludge (pot)
(air dired)
Sludge (pot)
(air dired)
Sludge (pot)
(air dired)
Range (and Na) of Control Tissue
Soil Application Rates Concentration Uptake^
pH (kg/ha) (Ug/g DW) Slope References
5 3 - 7.1 0-60 (2) 3.5 0 Furr et al., 1976b
(p. 761)
5.3 - 7.1 0-60 (2) 0.2 0.055
5.3 - 7.1 0-60 (2) 0.1 0.005
5.3 - 7.1 0-60 (2) , 0.3 0
5.3 - 7.1 0-60 (2) 1.1 0.080
5.3 - 7.1 0-60 (2) 0.07 0.00067
5.3 - 7.1 0-60 (2) 0.01 0.00033
a N - Number of application rates.
D Uptake slope = y/x! y = MB/8 tissue DM; x = kg/ha applied.
c NR = Not reported.
d Application rate calculated from soil concentration, assuming 1 pg/g - 2 kg/ha.
-------
TABLE 4-3. TOX1CITY OP CHROMIUM TO DOMESTIC ANIMALS AND WILDLIFE
Species (N)a
Chicken (24)
Chicken (52)
Chicken
Chicken
Rat (50)
Rat
Rat (16)
Rat (20)
Rat
Chemical Form
Fed
CrClj (CrIIl)
Na2CrO« (CrVI)
Na2CrO^ (CrVI)
CrCl3 (CrIIl)
Cr(CH3COO)3
KjCrO^ (CrVI)
K2CrO^ (CrVI)
K2Cr04 (CrVI)
CrCl3 (CrIIl)
Chromium III
Feed
Concentration
(Mg/g)
3
30
100
500
1000
2000
NR
NR
NR
NR
NR
NR
NR
NR
NR
NK
276
Water
Concentration
(mg/L)
NRb
NR
NR
NK
NR
NR
5
300
500
0.45
2.2
4.5
7.7
11
25
25
NR
Daily
Intake
(mg/kg BW)
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Duration
of Study
27 days
32 days
32 days
21 days
21 days
21 days
Life-term
180 days
180 days
1 year
1 year
1 year
1 year
1 year
1 year
1 year
140 days
Effect* References
No adverse effects NAS, 1980
No adverse effects
No adverse effects
No adverse effects
No adverse effects
Reduced growth
No adverse effects
No adverse effects
No adverse effects
No adverse effects
No adverse effects
No adverse effects .
Increased Cr in tissues
Increased Cr in tissues
Decreased water intake;
concentrated in tissue 9 times
more than Cr III but no toxic
signs
No adverse effects
No adverse effects
nicotinic acid
complex
-------
Table 4-3 (continued)
Species (N)a
House (SO)
House (54)
House (62)
Mouse
Dog, cat,
rabbit
-C- Young rats
i
t >
a*
Dogs
Feed Water Daily
Chemical Form Concentration Concentration Intake
Fed (mg/L) (mg/kg BW)
Cr(CH3COO)3 (Crlll)
Cr(VI)
Cr(CH3COO)3 (CrIII)
Cr(VI)
K2Cr20; (CrVI)
K2Cr(>4 (CrVI)
K2Cr04 (CrVI)
K2Cr04 (CrVI)
NR
NR
NR
NR
NR
NR
1.2 mg/g
2.8-5.7 g
5
5
5
10
NR
NR
NR
NR
NR
NR
NR
NR
1.9-5.5 mg/kg
body wt/day
NR
NR
Duration
of Study
Life-term
Life-term
Life-term
Life-term
29-685 days
29-685 days
Daily
Daily
Effects References
No adverse effects HAS, 1980
Reduced growth
No adverse effects
Increased Cr in tissues
None harmful NAS, 1974
None harmful
Maximum nontoxic U.S. EPA, 1978
effect
Fatal in 3 months
8 N = Number of animals in study.
b NR - Not reported.
-------
TABLE 4-4. UPTAKE OP CHROMIUM BY DOMESTIC ANIMALS AND WILDLIFE
Chemical
Species Form Fed
Guinea pigs Swiss chard grown
on sludge/soil
Beef steers Sludge-amended
pasture grass
i
Range
of Feed Tissue
Concentration
(tig/g DU)
1.0, 1.1, 1.1
2.68 - 9.56
Tissue
Analyzed
Liver
Muscle
Kidney
Liver
Muscle
Control Tissue
Concentration
(Mg/g DW)a
1.3,1.9,1.1
1.8,2.6,3.4
0.73d
0.73d
0.73d
Uptake6
Slope References
NCC Purr et al., 1976a (p. 88)
NCC
-0.003d Bert rand et al . , 1981 (p. 149)
0
0
When tissue concentrations were reported as wet weight, unless otherwise indicated a moisture content of 77Z was assumed for kidney, 70Z for
liver, and 72Z for muscle.
b Uptake slope * y/xi y = Mg/g animal tissue DU; x = Mg/g feed DM.
c Not calculated because change in feed concentration not considered significant.
d Tissue feed weight.
-------
SECTION 5
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Functions. Dover Publications, New York, NY.
Allaway, W. H. 1968. Agronomic Controls Over the Environmental Cycling
of Trace Elements. In; Norma A. G. (ed.), Advances in Agronomy.
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American Conference of Governmental and Industrial Hygienists. 1983.
In: Technical Resources Document for Public Comments. Methods for
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Municipal Environmental Research Laboratory, Cincinnati, OH.
Bertrand, J. E., M. C. Lutrick, G. T. Edds, and R. L. West. 1981.
Metal Residues in Tissues, Animal Performance and Carcass Quality
with Beef Steers Grazing Pensacola Bahiagrass Pastures Treated with
Liquid Digested Sludge. J. Ani. Sci. 1981. 53:1.
Boswell, F. C. 1975. Municipal Sewage Sludge and Selected Element
Applications to Soil: Effect on Soil and Fescue. J. Environ.
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Camp Dresser and McKee, Inc. 1983. New York City Special Permit
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Gary, E. E. 1982. Chromium in Air, Soil and Natural Waters. In:
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(ed'.), Elsevier Biomedical Press, New York, NY.
Chaney, R. L., and C. A. Lloyd. 1979. Adherence of Spray-Applied
Liquid Digested Sewage Sludge to Tall Fescue. J. Environ. Qual.
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Sewage Sludge to Cropland: Appraisal of Potential Hazards of the
Heavy Metals to Plants and Animals. Ames, IA.
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Weast (ed.), CRC Press, Inc., Boca Raton, FL.
Cunningham, J. D., J. A. Ryan, and D. R. Keeney. 1975. Phytotoxicity
in and Metal Uptake from Soil Treated with Metal-Amended Sewage
Sludge. J. Environ. Qual. 4(4):455-460.
5-1
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Donigian, A. S. 1985. Personal Communication. Anderson-Nichols & Co.,
Inc., Palo Alto, CA. May.
Farrell, J. B., and H. Wall. 1981. Air Pollutional Discharges from Ten
Sewage Sludge Incinerators. Draft Review Copy. U.S. Environmental
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Freeze, R. A., and J. A. Cherry. 1979. Groundwater. Prentice-Hall,
Inc., Englewood Cliffs, NJ.
Furr, A. K., A. W. Lawrence, and S. S. long. 1976a. Multi-Element and
Chlorinated Hydrocarbon Analysis of Municipal Sewage Sludges of
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Furr, A. K., W. C. Kelly, C. A. Bache, W. H. Gutenmann, and D. H. Lisk.
1976b. Multi-Element Absorption by Crops Grown on Ithaca Sludge-
Amended Soil. Bull. Environ. Contam. Toxicol. 16:756-763.
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.
Gelhar, L. W., and C. J. Axness. 1981. Stochastic Analysis of
Macrodispersion in 3-Dimensionally Heterogenous Aquifers. Report
No. H-8. Hydrologic Research Program, New Mexico Institute of
Mining and Technology, Soccorro, NM.
Helmke, P. A., W. P. Robarge, R. L. Korotev, and P. J. Schomberg. 1979.
Effects of Soil-Applied Sewage Sludge on Concentrations of Elements
in Earthworms. J. Environ. Qual. 8:322-327.
Hem, J. D. 1970. Study and Interpretation of the Chemical
Characteristics of Natural Water. EPA 600/52-83-113. U.S.
Government Printing Office. Washington, D.C.
National Academy of Sciences. 1974. Chromium. National Research
Council Committee on Medical and Biologic Effects of Atmospheric
Pollutants. National Academy of Sciences, Washington, D.C.
National Academy of Sciences. 1980. Mineral Tolerance of Domestic
Animals. National Academy of Sciences, Subcommittee on Mineral
Toxicity in Animals, Washington, D.C.
Naylor, L. M., and N. I. Mondy. 1984. Metals and PCBs in Potatoes
Grown in Sludge-Amended Soils. ASAE Technical Paper No. NAR 84-211.
For presentation at 1984 North Atlantic Regional Meeting. Amer.
Soc. Agric. Eng., St. Joseph, MI.
Page, A. L. 1974. Fate and Effects of Trace Elements in Sewage Sludge
When Applied to Agricultural Lands. EPA 570/2-74-005. U.S.
Environmental Protection Agency, Cincinnati, OH.
Pennington, J. A. T. 1983. Revision of the Total Diet Study Food Lists
and Diets. J. Am. Diet. Assoc. 82:166-173.
5-2
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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, Cincinnatti, OH.
Pierce, F. J., R. H. Dowdy, and D. F. Grigal. 1982. Concentrations of
Six Trace Metals in Some Major Minnesota Soil Series. J. Environ.
Qual. 2(3).
Ryan, J. A., H. R. Pahren, J. B. Lucas. 1982. Controlling Cadmium in
the Human Food Chain: A Review and Rationale Based on Health
Effects. Environ Res. 28:251.
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.
Tandon, S. K. 1982. Organic Toxicity of Chromium in Animals. In;
Biological and Environmental Aspects of Chromium. S. Langard
(ed.), Elsevier Biomedical Press.
Thornton, I., and P. Abrams. 1983. Soil Ingestion - A Major Pathway of
Heavy Metals into Livestock Grazing Contaminated Land. Sci. Total
Environ. 28:287-294.
U.S. Department of Agriculture. 1975. Composition of Foods.
Agricultural Handbook No. 8.
U.S. Environmental Protection Agency. 1977. Environmental Assessment
of Subsurface Disposal of Municipal Wastewater Sludge: Interim
Report. EPA/530/SW-547. Municipal Environmental Research
Laboratory, Cincinnati, OH.
U.S. Environmental Protection Agency. 1978. Reviews of the
Environmental Effects of Pollutants: III. Chromium. EPA 600/1-
78-023, U.S. Environmental Protection Agency, Cincinnati, OH, or
ORNL/EIS-80, Oak Ridge National Laboratory, Oak Ridge, TN.
U.S. Environmental Protection Agency. 1979a. Industrial Source Complex
(ISC) 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. 1979b. Air Quality Data for
Metals 1976 from the National Air Surveillance Networks.
EPA 600/4-79-054. Environmental Monitoring and Support Laboratory,
Research Triangle Park, NC.
U.S. Environmental Protection Agency. 1980. Ambient Water Quality
Criteria for Chromium. EPA 440/5-80-035. U.S. Environmental
Protection Agency. Office of Water Regulations and Standards.
Washington, D.C.
5-3
-------
U.S. Environmental Protection Agency. 1982. Fate of Priority
Pollutants in Publicly-Owned Treatment Works. Vol. I. EPA
440/1-82-303. U.S. Environmental Protection Agency. Effluent
Guidelines Division, Washington, D.C.
U.S. Environmental Protection Agency. 1983a. Assessment of Human
Exposure to Arsenic: Tacoma, Washington. Internal Document.
OHEA-E-075-U. Office of Health and Environmental Assessment,
Washington, D.C. July 19.
U.S. Environmental Protection Agency. 1983b. Rapid Assessment of
Potential Groundwater Contamination Under Emergency Response
Conditions. EPA 600/8-83-030.
U.S. Environmental Protection Agency. 1983c. Health Assessment
Document for Chromium. External Review Draft. EPA 600/8-83-014A.
U.S. Environmental Protection Agency. Research Triangle Park, NC.
U.S. Environmental Protection Agency. 1984a. Air Quality Criteria for
Lead. External Review Draft. EPA 600/8-83-028B. Environmental
Criteria and Assessment Office, Research Triangle Park, NC.
September.
U.S. Environmental Protection Agency. 1984b. Health Effects Assessment
for Trivalent Chromium. Program Office Draft. ECAO-CIN-H035.
U.S. Environmental Protection Agency. 1985. Water Quality Criteria for
Chromium. Unpublished.
Yopp, J. H., W. F. Schmid, and R. W. Hoist. 1974. Determination of
Maximum Permissible Levels of Selected Chemicals That Exert Toxic
Effects on Plants of Economic Importance in Illinois. PB-237 654.
U.S. Department of Commerce. National Technical Information
Service.
5-4
-------
APPENDIX
PRELIMINARY HAZARD INDEX CALCULATIONS FOR CHROMIUM
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING
A. Effect on Soil Concentration of Chromium
1. Index of Soil Concentration Increment (Index 1)
a. Formula
, _ (SC x AR) * (BS x MS)
l BS (AR + MS)
where:
SC = Sludge concentration of pollutant
(Ug/g DW)
AR = Sludge application rate (mt DW/ha)
BS = Background concentration of pollutant in
soil (ug/g DW)
MS = 2000 mt DW/ha = Assumed mass of soil in
upper 15 cm
b. Sample calculation
- (230.1 ug/g DW x 5 mt/ha) + (100 Ug/g DW x 2000 mt/ha)
100 ug/g DW (5 mt/ha + 2000 mt/ha)
B. Effect on Soil Biota and Predators of Soil Biota
1. Index of Soil Biota Toxicity (Index 2)
a. Formula
Ii x BS
Index 2 =
where:
II = Index 1 = Index of soil concentration increment
(unitless)
BS = Background concentration of pollutant in soil
(Ug/g DW)
TB = Soil concentration toxic to soil biota (ug/g
DW)
b. Sample calculation - Values were not calculated due
to lack of data.
A-l
-------
2. Index of Soil Biota Predator Toxicity (Index 3)
a. Formula
(II - 1)(BS x UB) + BB
Index 3 = -
where:
II = Index 1 = Index of soil concentration
increment (unitiess)
BS = Background concentration of pollutant in
soil (ug/g DW)
UB = Uptake slope of pollutant in soil biota
(Ug/g tissue DW [ug/g soil DW]'1)
BB = Background concentration in soil biota
(Ug/g DW)
TR = Feed concentration toxic to predator (yg/g
DW)
b. Sample calculation
0.02525 = [(1.003244-1) (100 ug/g DW x 0.5
Ug/g DW [ug/g soil DW]'1) + 50.5 ug/g DW] *
2000 Ug/g DW
C. Effect on Plants and Plant Tissue Concentration
1. Index of Phytotoxicity (Index 4)
a. Formula
' II x BS
Index 4 =
where:
!]_ = Index 1 = Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil (Ug/g DW)
TP = Soil concentration toxic to plants (ug/g
DW)
b. Sample calculation
n <;niA9-> - 1-003244 x 100 Ug/g DW
0.501622 - 20Q ug/g DW
A-2
-------
2. Index of Plant Concentration Increment Caused by Uptake
(Index 5)
a . Formula
(Ii - 1) x BS
Index 5 = = - x CO x UP + 1
BP
where:
Ij = Index 1 = Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil (ug/g DW)
CO = 2 kg/ha (ug/g)~* = Conversion factor
between soil concentration and application
rate
UP = Uptake slope of pollutant in plant tissue
(Ug/g tissue DW [kg/ha]"1)
BP = Background concentration in plant tissue
(Ug/g DW)
b. Sample calculation
i ninoi (1.Q0324A-1) x 100 Ug/g DW 2 kg/ha
1.0202126 - x
0.081 Ug/g tissue
X kg/ha i
3. Index of Plant Concentration Increment Permitted by
Phytotoxicity (Index 6)
a. Formula
PP
Index 6 = ~
where:
PP = Maximum plant tissue concentration
associated with phytotoxicity (ug/g DW)
BP = Background concentration in plant tissue
(Ug/g DW)
b. Sample calculation
252 ug/g DW
1.0 Ug/g DW
A-3
-------
C. Effect on Herbivorous Animals
1. Index of Animal Toxicity Resulting from Plant Consumption
(Index 7)
a. Formula
I5 x BP
Index 7 =
TA
where:
I5 = Index 5 = Index of plant concentration
increment caused by uptake (unitless)
BP = Background concentration in plant tissue
(Ug/g DW)
TA = Feed concentration toxic to herbivorous
animal (ug/g
b. Sample calculation
1.0202126 x 2.6 Ug/g DW
0.001.3 - 2000 ug/g DW
Index of Animal Toxicity Resulting from Sludge Ingestion
(Index 8)
Formula
BS x GS
If AR = 0, I8 = ^ -
SC x GS
if AR * o, i8 =
where:
AR = Sludge application rate (mt DW/ha)
SC = Sludge concentration of pollutant
(Ug/g DW)
BS = Background concentration of pollutant in
soil (ug/g DW)
GS = Fraction of animal diet assumed to be soil
(unitless)
TA = Feed concentration toxic to herbivorous
animal (ug/g
b. Sample calculation
100 ug/g DW x 0.05
If AR = 0, 0.0025 = 2000 Ug/g DW
230.1 Ug/g DW x O.Q5
If AR * 0, 0.0057525 = 200Q ug/g DW
A-4
-------
E. Effect on Humans
1. Index of Human Toxicity Risk Resulting from Plant
Consumption (Index 9)
a. Formula
[(I5 - 1) BP x DT] + DI
Index 9 =
ADI
where:
15 = Index 5 = Index of plant concentration
increment caused by uptake (unitless)
BP - Background concentration in plant tissue
(Ug/g DW)
DT = Daily human dietary intake of affected
plant~~trissue (g/day DW)
DI = Average daily human dietary intake of
pollutant (ug/day)
ADI = Acceptable daily intake of pollutant
(Ug/day)
b. Sample calculation (toddler)
0 000233 - K1-0471855 - 1) x 1.1 ug/g DW x 74.5 a/day] + 22 ug/dav
111,000 Ug/day
2. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Feeding on Plants
(Index 10)
a. Formula
[(15 - 1) BP x UA x DA] « DI
Index 10 = -> _
where:
15 = Index 5 = Index of plant concentration
increment caused by uptake (unitless)
BP = Background concentration in plant tissue
(Ug/g DW)
UA = Uptake slope of pollutant in animal tissue
(Ug/g tissue DW [ug/g feed DW]"1)
DA = Daily human dietary intake of affected
animal tissue (g/day DW)
DI = Average daily human dietary intake of
pollutant (ug/day)
ADI = Acceptable daily intake of pollutant
(Ug/day)
A-5
-------
b. Sample calculation (toddler)
01982 =
12-1) x 2.6 ug/g DW x 0.0 Ue/e tissuefug/g feed]"1 x 51.1 g/dayl + 22 Ug/day
~111,000 Ug/day
3. Index of Human Toxicity Risk Resulting from Consumption
of Animal Products Derived from Animals Ingesting Soil
(Index 11)
a. Formula
T n (BS x GS x UA x DA) * DI
If AR = 0, Index 11 = £j^
, T J (SC x GS x UA x DA) + DI
If AR ^ 0, Index 11 =
where;
AR = Sludge application rate (mt DW/ha)
BS = Background concentration of pollutant in
soil (Ug/g DW)
SC = Sludge concentration of pollutant
(Ug/g DW)
GS = Fraction of animal diet assumed to be soil
(unitless)
UA = Uptake slope of pollutant in animal tissue
(Ug/g tissue DW [ug/g feed DW"1]
DA = Average daily human dietary intake of
affected animal tissue (g/day DW)
DI = Average daily human dietary intake of
pollutant (ug/day)
ADI = Acceptable daily intake of pollutant
(Ug/day)
b. Sample calculation (toddler)
0.000198 =
LI ue/g DW x 0.05 x 0.0 Ug/g tissue fug/g feedl"1 x 51.1 g/day DW) f 22 Ug/day
111,000 Ug/day
4. Index of Human Toxicity Resulting from Soil Ingestion
(Index 12)
a. Formula
(II x BS x DS) + DI
Index 12 =
r . 10 (SC x PS) * DI
Pure sludge ingestion: Index iz - ADI
A-6
-------
where:
II = Index 1 = Index of soil concentration
increment (unitless)
SC = Sludge concentration of pollutant
(Ug/g DW)
BS = Background concentration of pollutant in
soil (ug/g DW)
DS = Assumed amount of soil in human diet
(g/day)
DI = Average daily dietary intake of pollutant
(Ug/day)
ADI = Acceptable daily intake of pollutant
(Ug/day)
b. Sample calculation (toddler)
n ._,,._, (1.003244 x 100 Ug/g DW x 5 g soil/day) + 22 Ug/day
0-0047173 = 111,000 yg/day
Pure sludge:
. nin«.,,, _ (230.1 Ug/g DW x 5 g soil/day) + 22 Ug/day
0.0105631 - 111,000 yg/day
5. Index of Aggregate Human Toxicity (Index 13)
a. Formula
3DI
Index 13 = I9 + IIQ + 111 + I12 ~ ADI
where:
19 = Index 9 = Index of human toxicity
resulting from plant consumption
(unitless)
= Index 10 = Index of human toxicity
resulting from consumption of animal
products derived from animals feeding on
plants (unitless)
~ Index H = Index of human toxicity
resulting from consumption of animal
products derived from animals ingesting
soil (unitless)
Il2 = In(iex 12 = Index of human toxicity
resulting from soil ingestion (unitless)
DI = Average daily dietary intake of
pollutant (ug/day)
ADI = Acceptable daily intake of pollutant
(yg/day)
A-7
-------
b. Sample calculation (toddler)
0.0047514 = (0.0002333 + 0.000198 + 0.000198 + 0.004717) -
II. LANDFILLING
A. Procedure
Using Equation 1, several values of C/CO 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,
t0, 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 estimates initial dilution in the aquifer to
give the initial concentration, C0, for the saturated zone
assessment. (Conditions for B, 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 unsaturated zone except for the definition of
certain parameters and choice of parameter values. The maxi-
mum concentration at the well, Cmax,_ is used to calculate the
index values given in Equations 4 and 5.
B. Equation 1: Transport Assessment
C(y,t) =i [exp(Ai) erfc(A2) + exp^) erfc(B2)] = P
-------
and where for the unsaturated zone:
C0 = SC x CF = Initial leachate concentration (ug/L)
SC = Sludge concentration of pollutant (mg/kg DW)
CF = 250 kg sludge solids/m3 leachate =
PS x 103
1 - PS
PS = Percent solids (by weight) of landfilled sludge
202
t = Time (years)
X = h = Depth to groundwater (m)
D* = a x V* (m2/year)
a = Dispersivity coefficient (m)
V* = 2 (m/year)
0 x R
Q = Leachate generation rate (m/year)
0 = Volumetric water content (unitless)
R = 1 + P(iry x Kd = Retardation factor (unitless)
0
Pdry = Dry bulk density (g/mL)
Kd = Soil sorption coefficient (mL/g)
H* =
R ,
U = Degradation rate (day -1)
and where for the saturated zone:
C0 = Initial concentration of pollutant in aquifer as
determined by Equation 2 (jjg/L)
t = Time (years)
Y = AS, = Distance from well to landfill (m)
D* = a x V* (m2/year)
Ct = Dispersivity coefficient (m)
V* = ^ x L (m/year)
V 0 x R
K = Hydraulic conductivity of the aquifer (m/day)
i = Average hydraulic gradient between landfill and well
(unitless)
0 = Aquifer porosity (unitless)
R = 1 + Pdr? x Kd = Retardation factor = 1 (unitless)
since Kd is assumed to be zero for the saturated
zone
C. Equation 2. Linkage Assessment
Q x W
C0 = cu x 365 [(K x i) t 0] x B
A-9
-------
where:
C0 = Initial concentration of pollutant in the saturated
zone as determined by Equation 1 (yg/L)
Cu = Maximum pulse concentration from the unsaturated
zone (pg/L)
Q = Leachate generation rate (m/year)
W = Width of landfill (m)
K = Hydraulic conductivity of the aquifer (m/day)
i = Average hydraulic gradient between landfill and well
(unitless)
-^: TTT and B > 2
K x i x 365
D. Equation 3. Pulse Assessment
C(X?t) = P(x,t) for 0 < t < t0
Co
C(x?t) P t
"O
where:
o
Cr
t0 (for unsaturated zone) = LT = Landfill leaching time
(years)
t0 (for saturated zone) = Pulse duration at the water
table (x = h) as determined by the following equation:
* C dt] -t- Cu
>t) = LXji as determined by Equation 1
co
E. Equation 4. Index of Groundwater Concentration Increment
Resulting from Landfilled Sludge (Index 1)
1. Formula
Cmav "*" BC
Index 1 =
BC
where:
cmax = Maximum concentration of pollutant at well -
Maximum of C(A2,,t) calculated in Equation 1
(Wg/L)
BC = Background concentration of pollutant in
groundwater (pg/L)
A-10
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2. Sample Calculation
* 6.26 ug/L + 6.5
6.5 ug/L
F. Equation 5. Index of Human Toxicity Resulting
from Groundwater Contamination (Index 2)
1. Formula
[(I I - 1) BC x AC] + DI
Index 2 =
where:
II - Index 1 = Index of groundwater concentration
increment resulting from landfilled sludge
BC = Background concentration of pollutant in
groundwater (ug/L)
AC = Average human consumption of drinking water
(L/day)
DI = Average daily human dietary intake of pollutant
(Ug/day)
ADI = Acceptable daily intake of pollutant (Ug/day)
2. Sample Calculation
n 0006qa - K1.96 - 1) x 6.5 US/L * 2 L/dav] + 65 US/day
0.000698 - 111,000 Ug/day
III. INCINERATION
A. Index of Air Concentration Increment Resulting from Incinerator
Emissions (Index 1)
1. Formula
(C x PS x SC x FM x DP) + BA
Index 1 = ££
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 (yg/m3)
BA = Background concentration of pollutant in urban
air (ug/m3)
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2. Sample Calculation
1.1735574 =
78 x 10~7 hr/sec x g/mg x 2660 kg/hr DW x 230.1 mg/kg DW x 0.003 x 3.4 yg/m3) +
0.010 yg/m3] -fr 0.010 yg/m3
B. Index of Human Cancer Risk Resulting from Inhalation of
Incinerator Emissions (Index 2)
1. Formula
[(!]_ - 1) x BA] + BA
Index 2 =
EC
where:
II = Index 1 = Index of air concentration increment
resulting from incinerator emissions
(unitless)
BA = Background concentration of pollutant in
urban air (yg/m-3)
EC = Exposure criterion (yg/m3)
2. Sample Calculation
- Kl.1735574 - 1) x 0.01 Ug/m31 * 0.01 Ug/m3
c >
8.5 x 10"5 Ug/mJ
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-12
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TABLE A-l. INPUT DATA VARYING IN LANDFILL ANALYSIS AND RESULT FOR EACH CONDITION
Condition of Analysis
Input Data
Sludge concentration of pollutant, SC (Hg/g DM)
Unsaturated zone
Soil type and characteristics
Dry bulk, density, Pjry (g/mL)
Volumetric water content, 6 (unitleas)
Soil sorption coefficient, Kj (mL/g)
Site parameters
Leachate generation rate, Q (m/year)
Depth to groundwater, h (m)
Disperflivity coefficient, a (m)
Saturated zone
Soil type and characteristics
Aquifer porosity, 0 (unitless)
Hydraulic conductivity of the aquifer,
K (m/day)
Site parameters
Hydraulic gradient, i (unitless)
Distance from well to landfill, At (m)
Dispersivity coefficient, a (m)
1
230.1
1.53
0.195
56.5
0.8
5
0.5
0.44
0.86
0.001
100
10
2
1499.7
1.53
0.195
56.5
0.8
5
0.5
0.44
0.86
0.001
100
10
3
230.1
1.925
0.133
16.8
0.8
5
0.5
0.44
0.86
0.001
100
10
4 5
230.1 230.1
NAb 1.53
NA 0.195
NA 56.5
1.6 0.8
0 5
NA 0.5
0.44 0.389
0.86 A. 04
0.001 0.001
100 100
10 10
6
230.1
1.53
0.195
56.5
0.8
5
0.5
0.44
0.86
0.02
50
5
7
1499.7
NA
NA
NA
1.6
0
NA
0.389
4.04
0.02
50
5
8
N«
N
N
N
N
N
N
N
H
N
N
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TABLE A-l. (continued)
I
>-
4>
Condition of Analyst!
Results
Unsaturated zone assessment (Equations 1 and 3)
Initial leachate concentration, Co (|Jg/L)
Peak concentration, Cu (pg/L)
Pulse duration, t0 (years)
Linkage assessment (Equation 2)
Aquifer thickness, B (m)
Initial concentration in saturated zone, C0
(Mg/L)
1
57500
591
486
126
591
2
375000
3850
486
126
3850
3
57500
1580
182
126
1580
4
57500
57500
5.00
253
57500
5
57500
591
486
23.8
591
6
57500
591
486
6.32
591
7
375000
375000
5.00
2.38
375000
8
N
N
N
N
N
Saturated zone assessment (Equations 1 and 3)
Maximum well concentration, Cmax (pg/L) 6.26 40.8
Index of groundwater concentration increment
resulting from landfilled sludge,
Index 1 (unitless) (Equation 4) 1.96 7.28
Index of human toxicity resulting
from groundwater contamination, Index 2
(unitless) (Equation 5) 0.000698 0.00132
6.26
1.06
6.26
1.96
33.3
6.12
236
37.4
8680 N
1340 0
0.000698 0.000698 0.00118
0.00484 0.157 0.000586
*H = Null condition, where no landfill exists; no value is used.
"NA = Not applicable for this condition.
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