SEFft
United States
Environmental Protection
Agency
Office of Water
Regulations and Standards
Washington. DC 20460
Water
June. 1985
Environmental Profiles
and Hazard Indices
for Constituents
of Municipal Sludge:
Cobalt
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PREFACE
This document is one of a series of preliminary assessments dealing
with chemicals of potential concern in municipal sewage sludge. The
purpose of these documents is to: (a) summarize the available data for
the constituents of potential concern, (b) identify the key environ-
mental pathways for each constituent related to a reuse and disposal
option (based on hazard indices), and (c) evaluate the conditions under
which such a pollutant may pose a hazard. Each document provides a sci-
entific basis for making an initial determination of whether a pollu-
tant, at levels currently observed in sludges, poses a likely hazard to
human health or the environment when sludge is disposed of by any of
several methods. These methods include landspreading on food chain or
nonfood chain crops, distribution and marketing programs, landfilling,
incineration and ocean disposal.
These documents are intended to serve as a rapid screening tool to
narrow an inicial 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 COBALT IN MUNICIPAL SEWAGE
SLUDGE 2-1
Landspreading and Distribution-and-Marketing 2-1
Landfilling 2-2
Incineration 2-2
Ocean Disposal 2-2
3. PRELIMINARY HAZARD INDICES FOR COBALT IN MUNICIPAL SEWAGE
SLUDGE 3-1
Landspreading and Distribution-and-Marketing 3-1
Effect on soil concentration of cobalt (Index 1) 3-1
Effect on soil biota and predators of soil biota
(Indices 2-3) 3-3
Effect on plants and plant tissue
concentration (Indices 4-6) 3-5
Effect on herbivorous animals (Indices 7-8) 3-10
Effect on humans (Indices 9-13) 3-13
Landfi 11 ing 3-19
Index of groundwater concentration increment resulting
from landfilled sludge (Index 1) 3-19
Index of human toxicity resulting from
groundwater contamination (Index 2) 3-25
Incineration 3-26
Ocean Disposal 3-26
4. PRELIMINARY DATA PROFILE FOR COBALT IN MUNICIPAL SEWAGE
SLUDGE 4-1
Occurrence 4-1
Sludge 4-1
Soil - Unpolluted 4-2
Water - Unpolluted 4-2
Air 4-3
Food 4-3
11
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TABLE OP CONTENTS
(Continued)
Page
Human Effects 4-4
Ingestion 4-4
Inhalation 4-4
Plant Effects 4-5
Phytotoxicity 4-5
Uptake 4-6
Domestic Animal and Wildlife Effects 4-7
Toxicity 4-7
Uptake 4-7
Aquatic Life Effects 4-7
Soil Biota Effects 4-7
Toxicity 4-7
Uptake 4-7
Physicochemical Data for Estimating Fate and Transport 4-7
5. REFERENCES 5-1
APPENDIX. PRELIMINARY HAZARD INDEX CALCULATIONS FOR
COBALT IN MUNICIPAL SEWAGE SLUDGE A-l
111
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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. Cobalt (Co) was initially identified as being of poten-
tial concern when sludge is landspread (including distribution and mar-
keting) or placed in a landfill.* This profile is a compilation of
information that may be useful in determining whether Co 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 employed in these calculations tend to
represent a reasonable "worst case"; analysis of error or uncertainty
has been conducted to a limited degree. The resulting value in most
cases is indexed to unity; i.e., values >1 may indicate a potential
hazard, depending upon the assumptions of the calculation.
The data used for index calculation have been selected or estimated
based on information presented in the "preliminary data profile", Sec-
tion A. 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 and landfill-
ing practices are included in this profile. The calculation formulae
for these indices are shown in the Appendix. The indices are rounded to
two significant figures.
* Listings were determined by a series of expert workshops convened
during March-May, 1984 by the Office of Water Regulations and
Standards (OWRS) to discuss landspreading, landfilling, incineration,
and ocean disposal, respectively, of municipal sewage sludge.
1-1
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SECTION 2
PRELIMINARY CONCLUSIONS FOR COBALT 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. LANDSPREADINC AND DISTRIBUTION-AND-MARKETING
A. Effect on Soil Concentration of Cobalt
Land application of sludge is not expected to increase Co
concentrations in soil except possibly a slight increase for
the highest application rate (500 mt/ha) of "typical" sludge
and possibly slight increases for high application rates (50
and 500 mt/ha) of the "worst" sludge concentration (see
Index 1).
B. Effect on Soil Biota and Predators of Soil Biota
Landspreading of sludge is not expected to result in concen-
trations of Co in soil that pose a toxic hazard to soil biota
(see Index 2). Landspreading of sludge is not expected to
result in Co concentrations in soil that pose toxic hazards to
predators of soil biota (see Index 3).
C. Effect on Plants and Plant Tissue Concentration
Application of sludge to Land is not expected to result in Co
concentrations in soil that pose a toxic hazard to plants (see
Index 4). Plant tissue concentrations of Co are not expected
to increase above background concentrations, except possibly
slight increases when "typical" sludge is applied at the
highest rate (500 mt/ha) and when "worst" sludge is applied at
a rate of 50 mt/ha. Moderate increases may be expected when
"worst" sludge is applied at a high rate (500 mt/ha) (see
Index 5). The highest uptake increment of Co by plants grown
on sludge-amended soil is not expected to be
precluded by the maximum plant tissue concentration increment
permitted by phytotoxicity (see Index 6).
D. Effect on Herbivorous Animals
Co concentrations in plants grown on sludge-amended soils
are not expected to pose a toxic hazard for herbivorous
animals consuming these plants (see Index 7). Inadvertent
ingestion of sludge-amended soil by herbivorous animals is not
expected to pose a toxic hazard due to Co (see Index 8).
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E. Effect on Humans
Conclusions were not drawn about the potential human health
hazard due to increased dietary intake of Co associated with
landspreading of sludge due to lack of data (see Indices 9-
13).
II. LANDPILLING
Landfilling of sludge may be expected to result in increased
concentrations of Co in groundwater substantially above background
concentrations (see Index 1). The human toxicity due to Co result-
ing from groundwater contamination was not determined due to lack
of data (see Index 2).
III. INCINERATION
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.
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 COBALT
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING
A. Effect on Soil Concentration of CobaLt
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 J*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 1(H mt/ha.
c. Data Used and Rationale
i. Sludge concentration of pollutant (SC)
Typical 11.6 Mg/g DW
Worst 40.0 Mg/g DW
Only four data points were immediately avail-
able on which to establish the maximum and
median concentration values. Three points were
from a study of three California sewage plants
(Bradford et al., 1975). The fourth point was
3-1
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taken from a study of a sewage plant in
Washington, D.C. (Furr et al., 1976). Study
concentration values of 40, 8, and 3 Mg/L were
reported by Bradford et al. (1975). Furr et
al. (1976) reported a sludge concentration of
15.1 ppm. Based on these data, 40 yg/L was
conservatively chosen as the 95th percentile
sludge concentration value. In order to arrive
at a median concentration, the value 15.1 ppm
was combined with the results from Bradford to
form the ordinal sequence, 3, 8, 15.1, and 40.
The mean of the middle values (8 and 15.1) was
calculated to be 11.6 ug/g (DW). This value
was conservatively chosen to represent the
median concentration value. Additional concen-
trations were reported by Sabey and Hart
(1975), Page (1974) and Bradford et al. (1975).
However, these values were not considered for
the calculations because they were derived from
the analysis of sludge extracts prepared from
the sludge. The resultant data would not be
analogous to those derived from sludge. (See
Section 4, p. 4-1.)
ii. Background concentration of pollutant in soil
(BS) = 8 yg/g DW
Background Co concentrations in soil range from
1 to 40 Ug/g with a "common" concentration of
8 ug/g (Allaway, 1968 as cited in Page, 1974).
It is assumed that the data are on DW basis.
(See Section 4, p. 4-2.)
d. Index 1 Values
Sludge Application Rate (me/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
1
1
1.0
1.0
1.0
1.1
1.1
1.8
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.)
Preliminary Conclusion - Land application of sludge
is not expected to increase Co concentrations in
soil except possibly a slight increase for the high-
est application rate (500 mt/ha) of "typical" sludge
and possibly slight increases for high application
rates (50 and 500 mt/ha) of the "worst" sludge
concentration.
3-2
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B. Effect on Soil Biota and Predators of Soil Biota
1. Index of Soil Biota Toxicity (Index 2)
a. Explanation - Compares pollutant concentrations Ln
sludge-amended soil with soil concentration shown to
be toxic for some organism.
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) = 8 yg/g DW
See Section 3, p. 3-2.
iii. Soil concentration toxic to soil biota (TB) =
300 ug/g DW
Hartenstein et al. (1981) reported growth inhi-
bition of earthworms at 300 to 3000 ug/g Co in
soil. (See Section 4, p. 4-12.)
d. Index 2 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical 0.027 0.027 0.027 0.029
Worst 0.027 0.027 0.029 0.048
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 - Landspreading of sludge is
not expected to result in concentrations of Co in
soil that pose a toxic hazard to soil biota.
2. 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.
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b. Assumptions/Limitations - Assumes pollutant form
bioconcentrated by soil biota is equivalent in tox-
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 I)
See Section 3, p. 3-2.
ii. Background concentration of pollutant in soil
(BS) = 8 ug/g DW
See Section 3, p. 3-2.
iii. Uptake slope of pollutant in soil biota (UB) -
0 Ug/g tissue DW (yg/g soil DW)'1
Calculations of uptake slopes yielded very low,
negative slopes (-0.00079 to -0.0017), indicat-
ing that sludge application was not increasing
the tissue concentrations of Co in earthworms
(Helmke et al., 1979). (See Section 4,
p. 4-13.)
iv. Background concentration in soil biota (BB) =
3.5 Mg/g DW
Helmke et al. (1979) reported concentrations of
Co in earthworms grown in control soils for
1971, 1972, and 1973 with concentrations of
3.3, 3.5, and 3.7 pg/g, respectively. (See
Section 4, p. 4-13.)
v. Peed concentration toxic to predator (TR) =
10 Ug/g DW
Based on the available data, poultry was chosen
as the most sensitive bird species, and as the
model earthworm predator. Turk and Kratzer
(I960, in NAS, 1980) indicated that Co concen-
trations of 4.7 ug/g (DW) cause no signs of
toxicosis in chicks. However, their study fur-
ther reported that severe toxicosis in chicks
occurred at Co concentrations of 50 ppm. In
addition, NAS (1980) determined that poultry
should be able to tolerate Co at 10 Ug/g DW in
their diet. Consequently, 10 Ug/g was chosen
conservatively as the threshold level for Co
toxicity to predators of soil biota. (See
Section 4, p. 4-10.)
3-4
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d. Index 3 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
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 result in Co concentrations in soil
biota that present toxic hazards to 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
concentration 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) = 8 Ug/g DW
See Section 3, p. 3-2.
iii. Soil concentration toxic to plants (TP) =
80 Ug/g DW
Immediately available data on Co soil concen-
trations toxic to plants are limited. The nor-
mal background concentration of Co in soils
ranges from 2 to 80 ppm (Page, 1974). The high
value of 80 ppm was conservatively chosen as
the value for phytotoxicity, assuming that
symptoms of phytotoxicity would be exhibited in
plants at Co concentrations above 80 ppm.
3-5
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Agarwala et al. (1977) indicated that 55 ppm Co
in a sand culture solution reduced the growth
of barley by 50 percent. However, this value
was not chosen to represent phytotoxicity
because Co was present in a nutrient solution,
a condition not analogous to sludge-amended
soils. (See Section 4, pp. 4-5 and 4-8.)
d. Index 4 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
0.10
0.10
0.10
0.10
0.10
0.11
0.11
0.18
e. Value Interpretation - Value equals factor by which
soil concentration exceeds phytotoxic concentration.
Value > 1 indicates a phytotoxic hazard may exist.
f. Preliminary Conclusion - Application of sludge to
land is not expected to result in Co concentrations
in soil that pose a toxic hazard to plants.
2. 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.
3-6
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ii. Background concentration of pollutant in soil
(BS) = 8 Hg/g DW
See Section 3, p. 3-2.
iii. Conversion factor between soil concentration
and application rate (CO) = 2 kg/ha
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 0.23 Ug/g tissue DW (kg/ha) -1
Human diet:
Fodder rape 0.23 lig/g tissue DW (kg/ha) -1
Fodder rape was the only plant grown on sludge-
amended soil for which uptake was studied.
Data from Bradford et al. (1975) for several
plant species were not used because the plants
were grown in solution culture and results were
not considered comparable. Of the two studies
available for fodder rape, one (Narwal et al.,
1983) found that sludge amendment decreased
tissue Co, whereas another showed an uptake
slope of 0.23 Ug/g tissue DW (kg/ha)"1
(Anderson and Nilsson, 1972 in Page, 1974).
The latter value is conservatively chosen to
represent all crops in the animal diet and it
is also used for the human diet in lieu of data
on crops consumed by humans. (See Section 4,
p. 4-9.)
v. Background concentration in plant tissue (BP)
Animal diet:
Fodder rape 1.6 Ug/g DW
Human diet:
Fodder rape 1.6 ug/g DW
The background concentration for fodder rape,
1.6 Ug/g (DW) is given as the control tissue
concentration in the study by Anderson and
Kilsson (1972, in Page, 1974). Although Narwal
et al. (1983) reported a value of 0.5 ug/g (DW)
as a control tissue concentration for fodder
rape, the associated uptake value was negative.
(See Section 4, p. 4-9.)
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d. Indexes Values
Sludge Application
Rate (rot/ha)
Sludge
Diet Concentration 05 50 500
Animal
Typical
Worst
1
1
1.0
1.0
1.0
1.2
1.2
2.8
Human Typical 1 1.0 1.0 1.2
Worst 1 1.0 1.2 2.8
e. Value Interpretation - Value equals factor by which
plant tissue concentration is expected to increase
above background when grown in sludge-amended soil.
f. Preliminary Conclusion - Plant tissue concentrations
of Co are not expected to increase above background
concentrations, except possibly slight increases
when "typical" sludge is applied at the highest rate
(500 mt/ha) and when "worst" sludge is applied at a
rate of 50 mt/ha. Moderate increases may be
expected when "worst" sludge is applied at a high
rate (500 mt/ha).
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
phytotoxicity.
c. Data Used and Rationale
i. Maximum plant tissue concentration associated
with phytotoxicity (PP)
Animal diet:
Barley leaf 55 Ug/g DW
Human diet:
Barley leaf 55 Ug/g DW
Bradford et al. (1975) reported "excessive and
often toxic concentrations" of Co in the leaves
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of bean, tomato, and barley plants. The
effects on the plants could not be attributed
only to Co since the sludge extracts contained
other heavy metals.
Agarwala et al. (1977) reported decreased yield
among barley plants grown in sand cultures when
iron was withheld and an excess of Co was
applied. The tissue concentration associated
with decreased yield was 55 Ug/g DW. The con-
centration of Co in the controls was <1 Ug/g«
These data were assumed to be representative
for plants in the human diet. (See Section 4,
p. 4-8.)
Due to lack of available data, it was not
possible to calculate separate indices for
plants included in human diets and plant serv-
ing as animal feed. Therefore, it is assumed
that barley is representative both of plants
serving as animal feed and as human feed.
Data reported by Narwal et al. (1983), Kinsley
et al. (1972, in Page, 1974), and Sabey and
Hart (1975) were not utilized for this index
because no adverse effects or toxicity levels
were reported.
ii. Background concentration in plant tissue (BP)
Animal diet:
Barley leaf 1 Ug/g DW
Human diet:
Barley leaf 1 Ug/g DW
The background concentration of 1 Ug/g DW was
reported by Agarwala et al. (1977) as the con-
trol tissue concentration for barley. This
value was chosen over the value reported by
Bradford et al. (1975) because the Bradford
study was conducted using a sand culture and
nutrient solutions (derived from sludge
extracts). These conditions and results are
not analogous to the conditions characteristic
of sludge-amended soils. (See Section 4,
p. 4-8.)
d. Index 6 Values
Plant Index Value
Barley leaf 55
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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 highest uptake incre-
ment of Co by plants grown on sludge-amended soil
(see Index 5) is not expected to be precluded by the
maximum plant tissue concentration increment
permitted by phytotoxicity.
D. 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.
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. 3-8).
ii. Background concentration in plant tissue (BP) =
1.6 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) = 10 pg/g DW
MAS (1980) reported that 10 yg/g Co is the
dietary tolerance level for cattle, swine, and
poultry. In poultry, 50 Ug/g causes severe
toxicosis. Cattle tolerated 26 Mg/g, and no
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adverse effects were observed in swine at
200 Mg/g. Therefore, 10 Mg/g is a conservative
choice. (See Section 4, p. 4-10.)
Index 7 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
0.16
0.16
0.16
0.16
0.16
0.20
0.19
0.45
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.
£. Preliminary Conclusion - Co concentrations in plants
grown on sludge-amended soils are not expected to
pose a toxic hazard for herbivorous animals
consuming these plants.
2. Index of Animal Toxicity 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 11.6 IJg/g DW
Worst 40.0 yg/g DW
See Section 3, p. 3-1.
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ii. Background concentration of pollutant in soil
(BS) = 8 Mg/g DW
See Section 3, p. 3-2.
iii. Fraction of animal diet assumed to be soil (GS)
= 5%
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 (Chancy and Lloyd, 1979; BosweLI,
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
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. Peed concentration toxic to herbivorous animal
-------
d. Index 8 Values
Sludge Application Rate (tut/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
0.04
0.04
0.058
0.2
0.058
0.2
0.058
0.2
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 - Inadvertent ingestion of
sludge-amended soil by herbivorous animals is not
expected to pose a toxic hazard due to Co.
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
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.
c. 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. 3-8).
ii. Background concentration in plant tissue (BP) =
1.6 Mg/g DW
The background concentration value used is for
the plant chosen for the human diet (see
Section 3, p. 3-7).
3-13
-------
iii. Daily human dietary intake of affected plant
tissue (DT)
Toddler 74.5 g/day
Adult 205 g/day
The uptake factor for fodder rape is assumed to
apply to all crops (except fruits), in lieu of
sufficient data for other crop varieties (see
Index 5K
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 PDA Revised Total
Diet (Pennington, 1983) and food groupings
listed by the U.S. EPA (1984). 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 120 Ug/day
Adult 360 Ug/day
U.S. EPA (1977a) reported average daily intake
of 5 to 40 yg is assumed to be too low.
Kazantizis (1981) reported Co daily intakes
ranged from 140 to 580 tig/day. The midpoint of
360 Ug/day was chosen conservatively. Toddlers
were assumed to eat one-third the amount eaten
by adults. (See Section 4, p. 4-3.)
v. Acceptable daily intake of pollutant
(ADI) - Data not immediately available.
d. Index 9 Values - Values were not calculated due to
lack of data.
e. 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.
f. Preliminary Conclusion - Conclusion was not drawn
because index values could not be calculated.
3-14
-------
2. Index of Human Tozicity 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 pro-
ducts 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
representative of all animal tissue comprised by the
daily human dietary intake (DA) used. Divides
possible variations in dietary intake into two
categories: toddlers (18 months to 3 years) and
individuals over 3 years old.
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. 3-8).
ii. Background concentration in plant tissue (DP) -
1.6 Mg/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)
= 0.1480 Ug/g tissue DW (ug/g feed DW)'1
A time weighted average of the data from a
study by Keener et al. (1949) was used to
establish the average daily consumption of Co
per 45.36 kg (100 Ib) body weight for two sam-
ples of cattle. For these calculations, it was
assumed that the cattle consumed daily quantit-
ies of Co equivalent to 2.5% of their body
weight. The calculated concentrations,
35.7 ug/g and 43.2 pg/g, were then used to
calculate the uptake slope (0.1480 yg/g tissue
DW) in animal tissue (beef liver). (See
Section 4, p. 4-11.)
3-15
-------
iv. Daily human dietary intake of affected animal
tissue (DA)
Toddler 0.97 g/day
Adult 5.76 g/day
The FDA Revised Total Diet (Pennington, 1983)
lists average daily intake of beef liver (fresh
weight) for various age-sex classes. The 95th
percentile of liver consumption (chosen in
order to be conservative) is assumed to be
approximately three time the mean values.
Conversion to dry weight is based on data from
the U.S. Department of Agriculture (1975).
v. Average daily human dietary intake of pollutant
(DI)
Toddler 120 pg/day
Adult 360 Ug/day
See Section 3, p. 3-14.
vi. Acceptable daily intake of pollutant
(ADI) - Data not immediately available.
d. Index 10 Values - Values were noc calculated due to
lack of data.
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - Conclusion was not drawn
because index values could not be calculated.
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.
3-16
-------
c. Data Used and Rationale
i. Animal tissue = beef liver
See Section 3, p. 3-15.
ii. Background concentration of pollutant in soil
-------
4. Index of Human Toxicity from Soil Ingeation (Index 12)
a. Explanation - Calculates the amount of pollutant in
the diec of a child who ingests soil (pica child)
amended with sludge. Compares this amount with ADI.
b. Assumptions/Limitations - Assumes that the pica
child consumes an average of 5 g/day of sludge-
amended soil. If an ADI specific 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 11.6 Ug/g DW
Worst 40.0 Ug/g DW
See Section 3, p. 3-1.
iii. Background concentration of pollutant in soil
(BS) = 8 yg/g DW
See Section 3, p. 3-2.
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 (1984).
v. Average daily human dietary intake of pollutant
(DI)
Toddler 120 yg/day
Adult 360 yg/day
See Section 3, p. 3-14.
3-18
-------
vi. Acceptable daily intake of pollutant
(ADI) - Data not immediately available.
d. Index 12 Values - Values were not calculated due to
lack of data.
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - Conclusion was not drawn
because index values were not calculated.
S. 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.
c. Data Used and Rationale - As described for Indices 9
to 12.
d. Index 13 Values - Values were not calculated due to
lack of data.
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - Conclusion was not drawn
because index values could not be calculated.
II. LANDPILLING
A. Index of Groundwater Concentration Increment Resulting from
Landfilled Sludge (Index 1)
1. Explanation 7 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
3-19
-------
Che 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
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^ values) are con-
sidered the best available for analysis of
metal transport from landfilled sludge. The
same soil types are also used for nonmetals for
convenience and consistency of analysis.
3-20
-------
(b) Dry bulk density (Pdry)
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. (COM),
1984).
(c) Volumetric water content (6)
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 Che 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.
3-21
-------
(c) Depth to groundwater (h)
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-
water of 5 m was observed (U.S. EPA, 1977b).
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, wich 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 11.6 mg/kg DW
Worst 40.0 mg/kg DW
See Section 3, p. 3-1.
(b) Degradation rate (ll) = 0 day"*
The degradation rate in the unsaturated zone is
assumed to be zero for all inorganic chemicals.
3-22
-------
(c) Soil sorption coefficient (K
-------
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 (unicless)
Worst 0.02 (unicless)
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 (A4)
Typical 100 m
Worse 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.
3-24
-------
(e) Width of landfill (W) = 112.8 m
The landfill is arbitrarily assumed to be
circular with an area of 10,000 m2.
iii. Chemical-specific parameters
(a) Degradation rate (y) = 0 day'1
Degradation is assumed not to occur in the
saturated zone.
(b) Background concentration of pollutant in
groundwater (BC) = 0.028 pg/L
The U.S. EPA (1980a) reported a range of Co
concentration of 0.0009 to 0.9 yg/L and a mean
of 0.028 Ug/L. (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 - Landfilling of sludge may be
expected to result in increased concentrations of Co in
groundwater substantially above background concentration.
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 Section 3, p. 3-27.
3-25
-------
b. Background concentration of pollutant in groundwater
(BC) = 0.028 Ug/L
See Section 3, p. v3-25.
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 mbst risk assessment studies.
d. Average daily human dietary intake of pollutant (Dl)
= 360 Ug/day
See Section 3, p. 3-14.
e. Acceptable daily intake of pollutant (ADI) - Data
not immediately available.
4. Index 2 Values - Values were not calculated due to lack
of data.
5. Value Interpretation - Value equals factor by which pol-
lutant 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 - Conclusion was not drawn because
index values could not be calculated.
III. INCINERATION
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.
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.
3-26
-------
TABLE 3-1. INDEX OF CROUNDWATER CONCENTRATION INCREMENT RESULTING FROM LANDFILLED SLUDGE (INDEX 1) AND
INDEX OF HUMAN TOXICITY RESULTING FROM CROUNDWATER CONTAMINATION (INDEX 2)
u>
K>
Site Characteristics
Sludge concentration
Unsaturated Zone
Soil type and charac-
teristics'1
Site parameters6
Saturated Zone
Soil type and charac-
teristics^
Site parameters^
Index 1 Value
Index 2 Value
1
T
T
T
T
T
12
Values
2
W
T
T
T
T
40
were not
3
T
W
T
T
T
12
calculated
Condition of
4
T
NA
W
T
T
12
due to lack of
Analysisa»b»c
5
T
T
T
W
T
60
data.
6 78
T UN
T NA N
T W N
T UN
U UN
280 8300 0.0
aT = Typical values used; W = worst-case values used; N = null condition, where no landfill exists, used as
basis for comparison; NA = not applicable for this condition.
blndex values for combinations other than those shown may be calculated using the formulae in the Appendix.
cSee Table A-l in Appendix for parameter values used.
^Dry bulk density (Pdry) and volumetric water content (9).
eLeachate generation rate (Q), depth to groundwater (h), and dispersivity coefficient (a).
^Aquifer porosity (0) and hydraulic conductivity of the aquifer (K.).
^Hydraulic gradient (i), distance from well to landfill (A2,), and dispersivity coefficient (a).
-------
SECTION 4
PRELIMINARY DATA PROFILE FOR COBALT IN MUNICIPAL SEWAGE SLUDGE
I. OCCURRENCE
A. Sludge
1. Frequency of Detection
Assume 100% due to ubiquitous nature
2. Concentration
15.1 ppm (DW) - median value for
Washington, D.C.
19.9 Mg/g (DW)
Comparison of saturation extract
composition of Co in sludge and
soil (ug/ml)
Furr et al.,
1976 (p. 87)
Helmke et al.,
1979 (p. 324)
Page, 197A
(p. 19)
Range
Mean
Median
Sludge
Soil
Sludge Soil Sludge Soil
0.04-0.35 <0.01-0.14 0.18 0.06 0.16
<0.01
Co concentracion of 0.001 Mg/g (DW)
from analysis of anaerobically and
aerobically digested sewage sludge
produced from a sewage treatment
plane in Denver.
Co concentracion (ug/g DW) in
sludges from chree sewage treatment
plants in southern California:
40.0
8.0
3.0
Comparison of Co saturation extracts Bradford
in sludges and California soils et al., 1975
(pg/ml) (p. 124)
Sabey and
Hart, 1975
(p. 253)
Bradford
et al., 1975
(p. 124)
Range
Sludge
Soil
0.02 to 0.19
<0.01 to 0.14
Mean
0.13
0.06
Median
0.16
<0.01
4-1
-------
Concentration of Co in sludge:
Range 11.3 to 2490 mg/kg DW
Median 30 mg/kg DW
B. Soil - Unpolluted
1. Frequency of Detection
Co widely distributed making up 25 ppm
of igneous rocks of earth's crust
2. Concentration
0.1 to 13 ppm
8 Mg/g common concentration
1 to 40 Ug/g range
Water - Unpolluted
1. Frequency of Detection
Many waters studied had Co below
detection limits
Observed in only 2.8% of U.S. surface
waters
2. Concentration
a. Freshwater
0.1 to 5 Ug/L
Range 0.001 to 0.048 mg/L, mean
0.017 mg/L observed in 44 of
1,577 surface streams in U.S.
b. Seawater
0.5 mg/L
0.27 mg/L
c. Drinking Water
0.1 to 5 Mg/L
Chaney, 1983
U.S. EPA, 1980a
(p. 26)
U.S. EPA, 1977a
(p. 191)
Allaway, 1968
in Page, 1974
(p. 33)
U.S. Geological
Survey 1970
(p. 201)
Page, 1974
(p. 25)
U.S. EPA, 1977a
(p. 190)
Page, 1974
(p. 25)
U.S. Geological
Survey 1970
(p. 11)
U.S. EPA, 1980a
(p. 15)
U.S. EPA, 1977a
(p. 191)
4-2
-------
d. Croundwater
Air
2.
Range 0.0009 to 0.9 Ug/L
Mean 0.028 Ug/L
Frequency of Detection
Detectable amounts of Co (<0.3 ng/m-')
observed in 90 of 750 air samples from
28 stations in the U.S.
Concentration
0.3 to 23 ng/m^ in Chicago air
U.S. EPA, 1980a
(p. 15)
E. Pood
1. Total Average Intake
5 to 40 ug/day - food
0.1 to 50 Ug/L in water (assume
2 L of water/day)
0.1 to 5 Ug/L drinking water
140 to 580 Ug/day
Concentration
2.
Food
U.S. EPA, 1977a
(p. 191)
U.S. EPA, 1977a
(p. 191)
Cone, (ppm)
U.S. EPA, 1977a
(p. 190)
Kazantizis, 1981
(p. 143)
Kazantizis, 1981
(p. 143)
References
From U.S. EPA, 1980b
Oats
Cabbage
Lettuce
Tomato
Potato
Corn
Meat
Milk
Meat
^.^^b^^—^
Whole
Head
Leaf
Fruit
Tuber
Kernel
Beef
Cow
Pig
0
0
0
0
0
0
0
0
.03
.14
.05
.07
.01
.08
.02
.11
to
to
to
to
to
to
to
to
0
0
0
0
0
0
0
0
0
.23
.07
.14
.06
.14
.02
.94
.06
.23
(WW)
(DW)
(WW)
(WW)
(WW)
(WW)
(WW)
(WW)
(WW)
Mitchell
Beeson,
Shroeder
Shroeder
Shroeder
Mitchell
Shroeder
Shroeder
Shroeder
, 1951
1941
et
et
et
al . ,
al.,
al. ,
1967
1967
1967
, 1951
et
et
et
al.,
al . ,
al. ,
1967
1967
1967
4-3
-------
II. HUNAN EFFECTS
A. Ingestion
1. Carcinogenicity
No carcinogenic effect demonstrated
for ingestion route.
2. Chronic Toxicity
a. ADI
No ADI available for Co.
b. Effects
No adverse gastrointestinal
effects are listed for Co. Co is
used as a treatment for anemia.
3. Absorption Factor
5 to 45%
B. Inhalation
1. Carcinogenicity
Data not immediately available.
2. Chronic Toxicity
a. Inhalation Threshold or MPIH
No MPIH available for Co.
b. Effects
Occupational exposure to Co in
the air may cause pneumoconiosis.
Pneumoconiosis reported to be
produced by air concentrations of
Co of 0.1 to 2 mg/m3
3. Absorption Factor
No data on respiratory absorption of
Co are available.
U.S. EPA, 1977a
(p. 199)
U.S. EPA, 1977a
(p. 192)
U.S. EPA, 1977a
(p. 191)
U.S. EPA, 1977a
(p. 196)
U.S. EPA, 1977a
(p. 196)
4-4
-------
4. Existing Regulations
0.1 mg/m3 time weighted average (TWA)
(Note: This value is given, but a
"see Notice of Intended Changes" note
is attached in the reference. The
intended change listed for Co metal,
dust and fume is 0.05 mg/m3 (TWA) and
0.1 mg/m3 (STEL).)V
ACGIH, 1983
III. PLANT EFFECTS
A. Phytotoxicity
Co (8.1 mg/kg DW) in sludge applied at 50
and 100 mt/ha increased yield of fodder
rape over controls.
58.9 ppm Co in sand culture solution
reduced growth of barley by 50%.
HC1 and hot water soluble Co (pg/g) in
sewage-amended soils from sewage farm and
effects on plants*
Narwal et al.,
1983 (pp. 359-
361)
Agarwala et al.,
1977 (p. 1303)
Rohde, 1962, in
Page, 1974
(p. 30)
Berlin Farm
Paris Farm
HC1
Hot water
Healthy
1.8
0.16
Unhealthy
3.0
0.30
Healthy
2.3
Unhealtl
3.6
-'Large concentration of manganese, copper, and zinc
also present.
Co concentration in soil following total
application of 84 metric tons of sludge for
12 years
Control Soil Treated Soil Amt. Applied
14.2 ppm 14.6 ppm 0.38 ppm
Co exhibits high affinity to soil organic
matter.
Domestic sludge application in excess of
1,000 metric tons/hectare with a Co concen-
tration of 10 ppm would be required to pro-
duce Co concentrations in excess of those
typically present in natural soils. To
reach maximum concentrations of the normal
range of Co in soils (2 to 80 ppm), an
Anderson and
Nilsson, 1972,
in Page, 1974
(p. 59)
Page, 1974
(p. 63)
Page, 1974
(pp. 71, 75)
4-5
-------
unrealistically high amount of sludge would
have to be applied.
With domestic sludge, toxicities to higher
plants caused by soil build-up of Co are
unlikely.
See Table 4-1.
Page, 1974
(p. 77)
B. Uptake
0.0 to 2.0 ppm (DW) in leaf, twig of 182
species of higher plants
U.S. EPA, 1980s
(p. 131)
Food
Onion
Peanut
Oats
Cabbage
Carrot
Barley
Lettuce
Tomato
Alfalfa
Pea
Potato
Spinach
Corn
Type
Bulb
Nut
Whole
Head
Root
Grain
Leaf
Fruit
Hay
Seed
Tuber
Leaf
Kernel
Cone.
0
0
0
0
0
0
0
0
0
0
.06
.03
.04
to
to
to
.0012
.10
.05
.01
.01
.07
.01
to
to
to
to
to
to
0
0
0
0
0
to
0
0
0
0
0
0
0
(ppm)
•
•
•
•
•
•
•
•
•
•
•
•
18
37
23
07
16
0.
14
06
62
24
14
34
02
(WW)
(WW)
(WW)
(DW)
(WW)
003 (DW)
(WW)
(WW)
(WW)
(WW)
(WW)
(WW)
(WW)
Uptake of Co in barley grown in sand
culture solution (ppm DW)
Control solution: O.S9 ppm
Co solution: 59 ppm
References
From U.S. EPA. 1980b
Schroeder et al., 1967
Schroeder et al., 1967
Mitchell, 1951
Beeson, 1941
Schroeder et al., 1967
Haller et al., 1969
Schroeder et al., 1967
Schroeder et al., 1967
Mitchell, 1951
Schroeder et al., 1967
Schroeder et al., 1967
Schroeder et al., 1967
Mitchell, 1975
Agarwala et al.,
1977 (p. 1304)
Control
Co2+
Roots
<1
4,060
Young
Leaves
<1
188
Old
Leaves
<1
220
Stem
<1
245
Inflorescence
<1
55
Co concentration of fodder rape grown on
sludge-amended soil
Control soil: 14.2 ppm
Sludge
Concentration
Anderson and
Nilsson, 1972,
in Page, 1974
(p. 45)
Sludge Concentration in Vegetable
Application Control Sludge
122 ppm DW
1.3 kg/ha
1.6 ppm DW
1.9 ppm DW
See Table 4-2.
4-6
-------
IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS
A. Toxicity
Under practical conditions, Co deficiency NAS, 1980
in ruminants is more likely than Co (p. 155)
toxicosis.
See Table 4-3.
B. Uptake
0.0 to 0.3 ppm (WW) in liver and kidney of U.S. EPA, 1980a
15 species of mammals (p. 131)
0.0 to 0.2 ppm (WW) in liver of 9 species of
birds
Animal Muscle Kidney Liver Milk
Cow 0.08 to 0.94 0.04 <0.16 0.02-0.06 Schroeder
Pig 0.11 to 0.23 et al., 1967,
Chicken leg=0.21 (All values ppm WW) in U.S. EPA,
Chicken egg=0.10 1980b.
See Table 4-4.
V. AQUATIC LIFE EFFECTS
Data not immediately available.
VI. SOIL BIOTA EFFECTS
A. Toxicity
See Table 4-5.
B. Uptake
3.3 to 3.7 yg/g DW in earthworms Helmke et al.,
1979
See Table 4-6.
VII. PUYSICOCHEMICAL DATA FOR ESTIMATING PATE AND TRANSPORT
Soil partition coefficient: 10 mL/g Gerritse et al.,
1982
Atomic weight: 58.9 The Merck Index,
Melting point: 1493°C 1983 (p. 345)
Boiling point: 3100°C
Density: 8.92
4-7
-------
TABLE 4-1. PHYTOTOXICITY OF COBALT
00
Plant/Tissue
Fodder rape
Corn/grain
Wheat
Bean/leaf
Tomato/leaf
Barley/leaf
Barley/
int lorescence
— . . • — ^
Experimental
Control Tissue Soil Application Tissue
Chemical Concentration Concentration Rate Concentration
For™ :PPHed Soil pH (ug/g DW) (ug/g DW) (kg/ha) (pg/g DW) Effects References
Anaerobically 5.6 0.50 2.02 0.405-0.810 0.06-0.07 Increased yield Narwal et al., 1983
stabilized
sludge (pot)
Anaerobically NR- NR NR 0.30 NR Increased yield .Unsley et al., 1972 in
digested sludge Page' 19"
(field)
Sludge" (f, eld) NR NR MR 0.075 NH No adverse effect Sabey and Hart, 1975
Aqueous sludge NR 2.5 NR NR 2.7-7.3 Excessive and Bradford et al . , 1975
(sand culture) °ften to"ic
NR 3.0 NR NR 3.9-10.8
MR 1.9 NR NR 2.9-4.0
CoSO$ (pot) NR <1 0.01 uMc 1 ramol/Lc 55 Decreased yield Agarwala et al., 1977
•> SlUage0cons!sted of SOX anaerobically digested primary and 501 aerobically digested uaste-activated sludges with a small quantity of primary
sludge.
c Applied as nutrient solution.
-------
TABLE 4-2. UPTAKE OF COBALT BY PLANTS
Plant/Tissue
Fodder rape
Barley/leaf
Bean/leaf
*-
1
\o
Tomato/leaf
Fodder rape
Chemical Range (and N)a of Control Tissue
Form Applied Application Rate Concentration
(study type) Soil pH (kg/ha) (ug/g DW)
Anaerobically stabilized 5.6 - 7.5 0 to 0.810 kg/ha (3) 0.5
sludge (pot) 0 to 0.81 kg/ha (3)
Saturation extracts NRC 0 to 0.4 (7) 1.9
of sludge products
Saturation extracts NR 0 to 0.4 (7) 2.5
of sludge products
Saturation extracts NR 0 to 0.4 (7) 3.0
of sludge products
Sludge NR 1.3 1.6
Uptake
Slopeb References
-0.368 Narwal et al . , 1983
2.132 Bradford et al., 1975
S.74 Bradford et al., 1975
-4. 854 Bradford et al., 1975
0.2308 Anderson and Nilsson, 1972
in Page, 1974
a N = Number of application rates, including control.
0 Uptake slope = y/x: x = kg/ha applied; y = pg/g plant tissue.
c NR - Not reported
-------
TABLE 4-3. TOXICITY OP COBALT TO DOMESTIC ANIMALS AND WILDLIFE
Peed Water
Chemical Porm Concentration Concentration
Species (N)a Fed (pg/g UW) (mg/L)
Cattle (2) NRb 35.7 to 43.2 NR
Cattle, sheep (NR) NR 10 NR
Chicks (NR) NR 4.7 NR
Chicks (NR) NR SO NR
Swine (NR) NR 200 NR
Poultry, swine (NR) NR 10 NR
Daily Intake Duration
(mg/100 kg of Study
bodyweight) (weeks) Effects
66 55 Tolerated by cattle
NR NR Appears to be safe level
NR NR No aigna of toxicosis
NR NR Severe toxicosis
NR NR No adverse effects
NR NR Should be tolerated
by both species
References
Keener et al., 1949
HAS, 1980
Turk and Kratzer,
in HAS, 1980
Turk and Kratzer,
in HAS, 1980
Huck and Clawson,
in HAS, 1980
HAS, 1980
1960
1960
1976
a N = Number of animals/treatment group.
b NR = Not reported.
-------
TABLE 4-4. UPTAKE OF COBALT BY DOMESTIC ANIMALS AND WILDLIFE
Chemical
Species (N)a Form Fed
Guinea pig (2-4) Swiss chard grown
in sludge-treated
soil
Cow CoSO^
Chicken NRf
Range (and N)b
of Feed Tissue
Concentration
(pg/g DW)
1.6 to 3.1 (3)
35.7 to 43.2 (2)
NR
Tissue
l.i ver
Kidney
Muscle
Liver
Kidney
Leg
Egg
Control Tissue
Concentration
(pg/g DW)
0.4
0.2
0.3
0.44 to 0.85
0.26 to 0.41
0.21
0.10
Uptake
Slopec'd
0.062
-0.0029
-0.06508
0.14BO
MCe
HC
NC
References
Furr et al., 1976
Keener et al., 1949
Schroeder et al., 1967
in U.S. EPA, 1980b
a N - number of animals/treatment group.
b N = Number of feed concentrations, including control.
c When tissue values were reported as wet weight, unless otherwise indicated a moisture content of 77Z was assumed for kidney, 70Z for liver and
72Z for muscle.
d Uptake slope = y/x: x = ug/g feed DW; y = pg/g tissue DW.
e NC = Not calculated due to lack of data.
f NR = Not reported.
-------
TABLE 4-5. TOXICITY OP COBALT TO SOIL BIOTA
Chemical
Species Form Applied Soil pH
Earthworm CoCl NR"
a NR = Not reported.
Nl
Soil Application
Concentration Rate
(Mg/g DW) (kg/ha)
300 to 3000 NR
Duration
of Study
(Weeks) Effects References
8 Toxic threshold Hartenstein et al., 1981
(growth inhibition)
-------
TABLE 4-6. UPTAKE OP COBALT BY SOIL BIOTA
Species
i
*""* 0- W
Soil
Concentration
Range (and N)a
Chemical Form (Ug/g DU)
,
Tissue
Analyzed
Control Tissue
Concentration
(Ug/g DH)
Uptake
Slopeb
References
HelfDke et al*t 19/9
• N = Number of soil concentrations, including control.
b Uptake slope = y/x: x = ug/g soil; y = |ig/g tissue.
-------
SECTION 5
REFERENCES
Abramowitz, M.T and I. A. Stegun. 1972. Handbook of Mathematical
Functions. Dover Publications, New York, NY.
American Conference of Governmental Industrial Hygienists. 1983.
Threshold Limit Values for Chemical Substances and Physical Agents
in the Work Environment with Intended Changes for 1983-84,
Cincinnati, OH.
Agarwala, S. C., S. S. Bisht, and C. P. Sharma. 1977. Relative
Effectiveness of Certain Metals in Producing Toxicity and Symptoms
of Iron Deficiency in Barley. Can. J. Bot. 55:1299-1307.
Bertrand, J. E., M. C. Lutrick, C. T. Edds, and R. L. West. 1981.
Metal Residues in Tissues, Animal Performance and Carcass Quality
with Beef Steers Crazing Pensacola Bahiagrass Pastures Treated with
Liquid Digested Sludge. J. Ani. Sci. 53:1.
Boswell, F. C. 1975. Municipal Sewage Sludge and Selected Element
Applications to Soil: Effect on Soil and Fescue. J. Environ.
Qual. 4(2):267-273.
Bradford, G. R., A. L. Page, L. J. Lund, and W. Olmstead. 1975. Trace
Element Concentrations of Sewage Treatment Plant Effluents and
Sludges: Their Interactions with Soils and Uptake by Plants. J.
Environ. Qual. 4(1}:123-127.
Camp Dresser and McKee, Inc. 1984. Development of Methodologies for
Evaluating Permissible Contaminant Levels in Municipal Wastewater
Sludges. Draft. Office of Water Regulations and Standards, U.S.
Environmental Protection Agency, Washington, D.C.
Chaney, R. L., and C. A. Lloyd. 1979. Adherence of Spray-Applied
Liquid Digested Sewage Sludge to Tall Fescue. J. Environ. Qual.
8(3):407-411.
Chaney, R. L. 1983. Potential Effects of Waste Constituents on the
Food Chain. In: Parr, Marsh and Kla (eds.), Land Treatment of
Hazardous Wastes. Noyes Data Corp., Park Ridge, NJ. pp. 152-240.
Donigian, A. S. 1985. Personal Communication. Anderson-Nichols & Co.,
Inc., Palo Alto, CA. May.
Freeze, R. A., and J. A. Cherry. 1979. Groundwater. Prentice-Hall,
Inc., Englewood Cliffs, NJ.
Furr, A. K., G. S. Stoewsand, C. A. Bache, and D. J. Lisk. 1976. Study
of Guinea Pigs Fed Swiss Chard Grown on Municipal Sludge-Amended
Soil. Archives of Environ. Health. March/April. 87-91.
5-1
-------
Gelhar, L. W., and C. J. Axness. 1981. Stochastic Analysis of
Macrodispersion in 3-Dimensionally Heterogeneous Aquifers. Report
No. H-8. Hydrologic Research Program, New Mexico Institute of
Mining and Technology, Soccorro, MM.
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.
Hartenstein, R., E. F. Neuhanser, and A. Narahara. 1981. Effects of
Heavy Metal and Other Elemental Additives to Actuated Sludge on
Growth of Eisema Foetida. J. Environ. Qual. 10(3):372-376.
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(3):322-327.
Kazantizis, G. 1981. Role of Cobalt, Iron, Lead, Manganese, Mercury,
Platinum, Selenium, and Titonium in Carcinogenesis. Env. Health
Perspectives. 28:143-161.
Keener, H. A., G. P. Percival, K. S. Manow, and G. H. Ellis. 1949.
Cobalt Tolerance in Young Dairy Cattle. J. Dairy Sci. 32:527-533.
Merck Index. 1983. 10th Edition. Merck and Co., Inc., Rahway, NJ.
p. 345.
Narwal, R. P., B. R. Singh, and A. R. Panhwar. 1983. Plant
Availability of Heavy Metals in Sludge Treated Soil: I. Effect of
Sewage Sludge and Soil pH on the Yield and Chemical Composition of
Rape. J. Enviorn. Qual. 12(3):358-365.
National Academy of Sciences. 1980. Mineral Tolerances of Domestic
Animals. National Review Council Subcommittee on Mineral Toxicity
in Animals, Washington, D.C. 154:161.
Page, A. L. 1974. Fate and Effects of Trace Elements in Sewage Sludge
When Applied to Agricultural Lands. EPA 670/2-74-005. 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.
Pettyjohn, W. A., D. C. Kent, T. A. Prickett, H. E. LeCrand, and F. E.
Witz. 1982. Methods for the Prediction of Leachate Plume
Migration and Mixing. U.S. EPA Municipal Environmental Research
Laboratory, Cincinnati, OH.
Ryan, J. A., H. R. Pahren, and J. B. Lucas. 1982. Controlling Cadmium
in the Human Food Chain: A Review and Rationale Based on Health
Effects. Environ. Res. 28:251-302.
5-2
-------
Sabey, B. R., and W. E. Hart. 1975. Land Application of Sewage Sludge:
I. Effect on Growth and Chemical Composition of Plants. J. Env.
Qual. 4(2):252-256.
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.
Thornton, I., and P. Abrams. 1983. Soil Ingestion - A Major Pathway of
Heavy Metals into Livestock Crazing 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. 1977a. Toxicology of Metals:
Volume II. EPA-600/1-77-022. U.S. Environmental Protection
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U.S. Environmental Protection Agency. 1977b. Environmental Assessment
of Subsurface Disposal of Municipal Wastewater Treatment Sludge:
Interim Report. EPA/530/SW-547. Municipal Environmental Research
Laboratory, Cincinnati, OH.
U.S. Environmental Protection Agency. 1980a. Biological Monitoring of
Toxic Trace Metals: Volume I. EPA-600/3-80-089.
U.S. Environmental Protection Agency. 1980b. Biological Monitoring of
Toxic Trace Metals: Volume II. EPA-600/3-80-090.
U.S. Environmental Protection Agency. 1983a. Assessment of Human Expo-
sure 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. 1984. Air Quality Criteria for
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Criteria and Assessment Office, Research Triangle Park, NC.
September.
U.S. Geological Survey. 1970. Study and Interpretation of the Chemical
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Supply Paper 1473 by Hem, J. D.
5-3
-------
APPENDIX
PRELIMINARY HAZARD INDEX CALCULATIONS FOR COBALT
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING
A. Effect on Soil Concentration of Cobalt
1. Index of Soil Concentration Increment (Index 1)
a. Formula
_ . . (SC x AR) + (BS x MS)
Index 1 = BS (AR + MS)
where:
SC - Sludge concentration of pollutant
(yg/g DW)
AR = Sludge application rate (mt DW/ha)
BS = Background concentration of pollutant in
soil (yg/g DW)
MS = 2000 mt DW/ha = Assumed mass of soil in
upper 15 cm
b. Sample calculation
(11.6 Ug/g DW x 5 mt/ha) * (8 Ug/g DW x 2000 mt/ha)
1<0 8 yg/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
x BS
Index 2 =
where:
1} = Index 1 = Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil (yg/g DW)
TB = Soil concentration toxic to soil biota
(yg/g DW)
A-l
-------
b. Sample calculation
m 1.0 x 8 Mg/S DW
Ot02' 300 ug/g DW
2. Index of Soil Biota Predator Tozicity (Index 3)
a. Formula
(Ii - 1XBS x UB) + BB
index 3 = - s -
where:
II = Index 1 = Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil (ug/g DW)
UB = Uptake slope of pollutant in soil biota
(Mg/g tissue DW [Mg/g soil DW]'1)
BB = Background concentration in soil biota
(Mg/g DW)
TR = Feed concentration toxic to predator (pg/g
DW)
b. Sample calculation
0.35 = [(1.0 -1) (8 Mg/g DW x 0 Mg/g DW
[Mg/g soil DW]-1) + 3.5 Mg/g DW] t
10 yg/g DW
C. Effect on Plants and Plant Tissue Concentration
1. Index of Phytotoxicity (Index 4)
a. Formula
x BS
Index 4 =
where:
II = Index 1 = Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil
-------
b. Sample calculation
_ ._ _ 1.0 x 8 ue/e DW
°'10 "80 ug/g DW
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:
1} = Index 1 - Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil (pg/g DW)
CO = 2 kg/ha (ug/g)~* = Conversion factor
between soil concentration and application
rate
UP = Uptake slope of pollutant in plant tissue
(yg/g tissue DW [kg/ha]'1)
BP = Background concentration in plant tissue
(Ug/g DW)
b. Sample calculation
. n (1-1) x 8 ug/g DW 2 kg/ha
1
-------
b. Sample calculation
„ _ 55 Mg/g DW
" ~ 1 Mg/g DW
C. Effect on Herbivorous Animals
1. Index of Animal Toxicity Resulting from Plant Consumption
(Index 7)
a. Formula
Is x BP
Index 7 = - -
where:
15 = Index 5 = Index of plant concentration
increment caused by uptake (unitless)
BP = Background concentration in plant tissue
(Mg/g DW)
TA = Feed concentration toxic to herbivorous
animal (Mg/g DW)
b. Sample calculation
n ,, _ 1.0 x 1.6 Mg/g DW
°'16 ' 10 Ug/g DW
2. Index of Animal Toxicity Resulting from Sludge Ingestion
(Index 8)
a. Formula
IfAR-0. 18=*
If AR * 0, Ig -
where:
AR = Sludge application rate (mt DW/ha)
SC = Sludge concentration of pollutant
(Mg/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 (Mg/g DW)
A-4
-------
b. Sample calculation
0.058 - - °'°5
B. Effect on Humans
1. Index of Human Toxicity 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
(pg/g DW)
DT = Daily human dietary intake of affected
plant tissue (g/day DW)
DI = Average daily human dietary intake of
pollutant (tig/day)
ADI = Acceptable daily intake of pollutant
(Ug/day)
b. Sample calculation (toddler) - Values were not
calculated due to lack of data.
2. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Feeding on Plants
(Index 10)
a. Formula
[(I5 - 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
(yg/g tissue DW [yg/g feed DW]"1)
DA = Daily human dietary intake of affected
animal tissue (g/day DW)
A-5
-------
DI = Average daily human dietary intake of
pollutant (yg/day)
ADI = Acceptable daily intake of pollutant
(yg/day)
b. Sample calculation (toddler) - Values were not
calculated due to lack of data.
3. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Ingesting Soil
(Index 11)
a. Formula
_, A_ . _ . .. (BS x GS x UA x DA) + DI
If AR = 0, Index 11 = rrr
Tr A0 , A _ . ,, (SC x GS x UA x DA) + DI
If AR # 0, Index 11 = TZT
where:
AR = Sludge application rate (mt DW/ha)
BS = Background concentration of pollutant in
soil (yg/g DW)
SC = Sludge concentration of pollutant
(yg/g DW)
GS = Fraction of animal diet assumed to be soil
(unitless)
UA = Uptake slope of pollutant in animal tissue
(yg/g tissue DW [yg/g feed DW1!
DA = Average daily human dietary intake of
affected animal tissue (g/day DW)
DI = Average daily human dietary intake of
pollutant (yg/day)
ADI = Acceptable daily intake of pollutant
(yg/day)
b. Sample calculation (toddler) - Values were not calculated
due to lack of data.
4. Index of Human Toxicity Resulting from Soil Ingestion
(Index 12)
a. Formula
(II x BS x OS) + DI
Index 12 =
ADI
Pure sludge ingestion: Index 12 =
A-6
-------
where:.
Ij = Index 1 = Index of soil concentration
increment (unitless)
SC = Sludge v concentration of pollutant
(Ug/g DW)
US = Background concentration of pollutant in
soil (yg/g DW)
DS = Assumed amount of soil in human diet
(g/day)
DI = Average daily dietary intake of pollutant
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until equilibrium is reached. Assuming a 5-year pulse input
from the landfill, Equation 3 is employed to estimate the con-
centration vs. time data at the water table. The
concentration vs. time curve is then transformed into a square
pulse having a constant concentration equal to the peak
concentration, Cu, from the unsaturated zone, and a duration,
to, chosen so that the total areas under the curve and the
pulse are equal, as illustrated in Equation 3. This square
pulse is then used as the input to the linkage assessment,
Equation 2, which 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) =* [expUj) erfc(A2) + exp^) erfc(B2)] = P(x»t)
Requires evaluations of four dimensionless input values and
subsequent evaluation of the result. Exp(Aj) denotes the
exponential of A}, e *, where erfc(A2) denotes the
complimentary error function of A2. Erfc(A2) produces values
between 0.0 and 2.0 (Abramowitz and Stegun, 1972).
where:
Al = X_ [V* - (V*2 + 4D* x
Al 2D*
X - t (V*2 + 4D* x u*
A2 (AD* x t)±
Bl = X [V* + (V*2 + 4D* x
1 5 n*
2D*
y » t (V*2
82 ' <4D*
and where for the unsaturated zone:
C0 = SC x CF = Initial leachate concentration (yg/L)
SC = Sludge concentration of pollutant (mg/kg DW)
CF = 250 kg sludge solids/m3 leachate =
PS x 103
1 - PS
A-8
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PS = Percent solids (by weight) of landfilled sludge =
20%
t = Time (years)
X = h = Depth to groundwater (m)
D* = a x V* (m2/year)
a = Dispersivity coefficient (m)
u* = —9— (m/year)
0 x R
Q = Leachate generation rate (m/year)
0 = Volumetric water content (unitless)
R = 1 + drv x KJ = Retardation factor (unitless)
0
pdry = Drv bulk density (g/mL)
K
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K = Hydraulic conductivity of the aquifer (m/day)
i = Average hydraulic gradient between landfill and well
(unitless)
0 = Aquifer porosity (unitless)
B = Thickness of saturated zone (m) where:
O v W x f)
B > V X. " *, " and B > 2
— K x i x 365 —
D. Equation 3. Pulse Assessment
P(X,t) for 0 £ t < t
C(X>t) = P t0
co
where :
t0 (for unsaturated zone) = LT = Landfill leaching time
(years)
to (for saturated zone) = Pulse duration at the water
table (x = h) as determined by the following equation:
t0 - [ / " C dt] t Cu
C( Y t )
P(X»t) = — p — as determined by Equation 1
co
B. Equation 4. Index of Groundwater Concentration Increment
Resulting from Landfilled Sludge (Index 1)
1. Formula
T A , BC
Index 1 =
where:
Cmax = Maximum concentration of pollutant at well =
Maximum of C(Al,t) calculated in Equation 1
(Ug/D
BC = Background concentration of pollutant in
groundwater (yg/L)
2. Sample Calculation
0.316 ue/L •*• 0.028 ug/L
~ 0.028 Ug/L
A-10
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P. Equation 5. Index of Human Tozicity Resulting from
Groundwater Contamination (Index 2)
1. Formula
[(Ij - 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 (yg/L)
AC = Average human consumption of drinking water
(L/day)
DI = Average daily human dietary intake of pollutant
(yg/day)
ADI = Acceptable daily intake of pollutant (yg/day)
2. Sample Calculation - Values were not calculated due to
lack of data.
III. INCINERATION
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.
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-ll
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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 (ug/g DW)
Unsaturated zone
Soil type and characteristics
Dry bulk density, ?dry (g/mL)
Volumetric water content, 6 (unit less)
Soil sorption coefficient, K
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TABLE A-l. (continued)
u>
Results
Unsaturaled zone assessment (Equations 1 and 3)
Initial leachate concentration, Co (gg/L)
Peak concentration, Cu (pg/L)
Pulse duration, to (years)
Linkage assessment (Equation 2)
Aquifer thickness, B (m)
Initial concentration in saturated zone, Co
(Mg/D
Saturated zone assessment (Equations 1 and 3)
Maximum well concentration, Cmax (gg/L)
Index of groundwater concentration increment
resulting from landfilled sludge.
Index 1 (unitless) (Equation 4)
Index of human toxicity resulting from
groundwater contamination, Index 2
(unitless) (Equation 5)
12 3 4 5 6 1 •
2900 10000 2900 169000 2900 2900 10000 N
8.69 30.0 151 169000 8.69 8.69 10000 N
1670 1670 95.9 5.00 1670 1670 5.00 N
126 126 126 253 23.8 6.32 2.38 N
8.69 30.0 151 2900 8.69 8.69 10000 M
0.316 1.10 0.315 0.315 1.66 7.87 231 N
12.3 39.9 12.3 12.3 60.2 282 8270 0
Values were not calculated due to lack of data.
aN = Null condition, where no landfill exists; no value is used.
bNA = Not applicable for this condition.
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