Unite J States
Environmental Protsction
Agency
Office of Water
Regulations and Standards
Washington, DC 20*60
V/arer
Juno,
invieonmenta
t **R Jl*i' IsJ <**>'"*%' ^ g*«?
SilQr' ncd^Sai
Selenium
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PREFACE
This document is one of a series of preliminary assessments dealing
with chemicals of potential concern in municipal sewage sludge. The
purpose of these documents is to: (a) summarize the available data for
the constituents of potential concern, (b) identify the key environ-
mental pathways for each constituent related to a reuse and disposal
option (based on hazard indices), and (c) evaluate the conditions under
which such a pollutant may pose a hazard. Each document provides a sci-
entific basis for making an initial determination of whether a pollu-
tant, at levels currently observed in sludges, poses a likely hazard to
human health or the environment when sludge is disposed of by any of
several methods. These methods include landspreading on food chain or
nonfood chain crops, distribution and marketing programs, landfilling,
incineration and ocean disposal.
These documents are intended to serve as a rapid screening tool to
narrow an initial list of pollutants to those of concern. If a signifi-
cant hazard is indicated by this preliminary analysis, a more detailed
assessment will be undertaken to better quantify the risk from this
chemical and to derive criteria if warranted. If a hazard is shown to
be unlikely, no further assessment will be conducted at this time; how-
ever, a reassessment will be conducted after initial regulations are
finalized. In no case, however, will criteria be derived solely on the
basis of information presented in this document.
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TABLE OP CONTENTS
Page
PREFACE i
1. INTRODUCTION 1-1
2. PRELIMINARY CONCLUSIONS FOR SELENIUM IN MUNICIPAL SEWAGE
SLUDGE 2-1
Landspreading and Distribution-and-Marketing 2-1
Landf illing 2-2
Incineration 2-2
Ocean Disposal 2-2
3. PRELIMINARY HAZARD INDICES FOR SELENIUM IN MUNICIPAL SEWAGE
SLUDGE 3-1
Landspreading and Distribution-and-Marketing 3-1
Effect on soil concentration of selenium (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) 3-4
Effect on herbivorous animals (Indices 7-8) 3-9
Effect on humans (Indices 9-13) 3-12
Landf illing 3-21
Index of groundwater concentration increment resulting
from landfilled sludge (Index 1) 3-21
Index of human tbxicity resulting from
groundwater contamination (Index 2) 3-27
Incineration 3-29
Index of air concentration increment resulting
from incinerator emissions (Index 1) 3-29
Index of human toxicity resulting from
inhalation of incinerator emissions (Index 2) 3-31
Ocean Disposal 3-33
11
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TABLE OP CONTENTS
(Continued)
Page
4. PRELIMINARY DATA PROFILE FOR SELENIUM IN MUNICIPAL SEWAGE
SLUDGE 4-1
Occurrence 4-1
Sludge 4-1
Soil - Unpolluted 4-2
Water - Unpolluted 4-2
Air 4-3
Food 4-4
Human Effects 4-6
Ingestion 4-6
Inhalation 4-7
Plant Effects 4-8
Phytotoxicity 4-8
Uptake 4-8
Domestic Animal and Wildlife Effects 4-9
Toxicity 4-9
Uptake 4-10
Aquatic Life Effects 4-10
Soil Biota Effects ; 4-10
Physicochemical Data for Estimating Fate and Transport 4-10
5 . REFERENCES 5-1
APPENDIX. PRELIMINARY HAZARD INDEX CALCULATIONS FOR
SELENIUM 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. Selenium (Se) 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 Se
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 repre-
sent 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 (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 SELENIUM 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-AND-MARKETING
A. Effect on Soil Concentration of Selenium
The concentration of Se in sludge-amended soil is expected to
increase as the concentration of Se in sludge and the sludge
application rate increase (see Index 1).
B. Effect on Soil Biota and Predators of Soil Biota
Conclusions were not drawn because index values could not be
calculated due to lack of data (see Indices 2 and 3).
C. Effect on Plants and Plant Tissue Concentration
A phytotoxic hazard due to Se in sludge-amended soil is not
expected to occur (see Index 4). The concentration of Se in
tissues of plants grown in sludge-amended soil is expected to
increase above background by a factor ranging from 1.2 when
typical sludge is applied at 5 mt/ha to 73 when the worst
sludge is applied at 500 mt/ha. These factors apply for
plants in animal and human diets (see Index 5). The highest
expected factor for the increase of Se in plant tissues is not
expected to be precluded by phytotoxicity (see Index 6).
D. Effect on Herbivorous Animals
A hazard due to Se may exist for animals which feed on plants
grown in sludge-amended soil only when the worst sludge is
applied at a high cumulative rate (500 mt/ha) (see Index 7).
No hazard due to Se is expected for animals which incidentally
ingest sludge-amended soil while grazing (see Index 8).
E. Effect on Humans
A health hazard due to Se from consumption of plants grown in
sludge-amended soil is expected for toddlers only when sludge
with a high Se concentration is applied at a high rate
(500 mt/ha) and for adults when typical or worst-case sludge
is applied at a high rate (500 mt/ha) (see Index 9).
Consumption of animal products derived from animals which had
fed on plants grown in sludge-amended soil is expected to pose
2-1
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a health hazard due to Se for toddlers when typical and worst-
case sludge is applied at a high rate (500 mt/ha), and for
adults when typical sludge is applied at a high rate
(500 mt/ha) and when the worst-case sludge is applied at
50 mt/ha or greater (see Index 10).
No human health hazard due to Se is expected from consumption
of animal products derived from animals which had incidentally
ingested sludge-amended soil while grazing (see Index 11).
No human health hazard due to Se is expected when either
sludge-amended soil or pure sludge is ingested (see
Index 12).
The aggregate amount of Se in the human diet resulting from
landspreading of sludge is expected to pose a health hazard
when sludge containing a typical concentration of Se is
applied at a high rate or when sludge containing a high con-
centration of Se is applied at a rate of 50 mt/ha or greater
(see Index 13).
II. LANDPILLING
An increase in the concentration of Se in groundwater at the well
due to leaching from a sludge landfill is expected when worst-case
conditions occur for the site parameters in the saturated zone, or
for all conditions, simultaneously (see Index 1). No human health
risk due to Se in groundwater at the well is expected when sludge
is disposed of in a landfill (see Index 2).
III. INCINERATION
The concentration of Se in air is expected to moderately increase
above background levels when sludge is incinerated (see Index 1).
A human health hazard due to the release of Se into air when sludge
is incinerated is not expected to occur (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 SELENIUM
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING
A. Effect on Soil Concentration of Selenium
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 S5Q kg available
nitrogen per hectare.
50 mt/ha Higher application as may be used on pub-
lic 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 10-* mt/ha.
c. Data Used and Rationale
i. Sludge concentration of pollutant (SC)
Typical 1.111 ug/g DW
Wors\ 4.848 Mg/g DW
The typical and worst sludge concentrations are
the median and 95th percentile values statis-
tically derived from sludge concentration data
3-1
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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) = 0.21 yg/g DW
Yopp et al. (1974) reported that the Se content
for most soils ranges from 0.1 to 0.2 yg/g.
Allaway (1968) reported an average Se concen-
tration in soils of 0.5 yg/g with a range of
0.1 to 2.0 yg/g. Se content in seleniferous
soils normally ranges from 1.0 to 6.0 Ug/g
(Yopp et al., 1974); however, these soils are
not considered in the present analysis because
of their limited geographical distribution.
Cappon (1984) analyzed garden soil and reported
a concentration of 0.21 yg/g of soil, dry
weight. This value was selected as the repre-
sentative background Se concentration in soil
since it falls within the ranges reported for
normal soils and since it was the only value
specified as being on a dry weight basis. (See
Section 4, p. 4-2.)
d. Index 1 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical 1.0 1.0 1.1 1.9
Worst 1.0 1.1 1.5 5.4
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 - The concentration of Se in
sludge-amended soil is expected to increase as the
concentration of Se in sludge and the sludge
application rate increase.
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) = 0.21 Ug/g DW
See Section 3, p. 3-2.
iii. Soil concentration toxic to soil biota (TB) -
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 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 1)
See Section 3, p. 3-2.
ii. Background concentration of pollutant in soil
(BS) = 0.21 Ug/g DW
See Section 3, p. 3-2.
iii. Uptake slope of pollutant in soil biota (UB) -
Data not immediately available.
3-3
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iv. Background concentration in soil biota (BB) -
Data not immediately available.
v. Peed concentration toxic to predator (TR) -
Data not immediately available.
d. Index 3 Values - Values were not calculated due to
lack of data.
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 - Conclusion was not drawn
because index values could not be calculated.
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) = 0.21 ug/g DW
See Section 3, p. 3-2.
iii. Soil concentration toxic to plants (TP) =
1.12 ug/g DW
Yopp et al. (1974) reported that the majority
of crops of economic importance in Illinois
were severely affected by Se levels of 1.8 ppm
in soil solution and 'recommended this value as
the maximum permissible level for Se. The
effects associated with this concentration were
leaf chlorosis and thickened roots in alfalfa
and growth reduction in subterranean clover.
However, phytotoxicity in terms of growth
reduction was shown for millet at even lower
3-4
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concentrations (0.9 ppm). It is assumed that
the Se concentrations were reported on a wet
weight basis. Assuming that the saturated
moisture content of soil is 20 percent, conver-
sion from wet weight to dry weight yields an Se
concentration of 1.12 Ug/g DW for millet. (See
Section 4, p. 4-12.)
d. Index 4 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5 50 500
Typical
Worst
0.19
0.19
0.19
0.20
0.21
0.29
0.35
1.0
e. Value Interpretation - Value equals factor by which
soil concentration exceeds phytotoxic concentration.
Value > 1 indicates a phytotoxic hazard may exist.
f. Preliminary Conclusion - A phytotoxic hazard due to
Se in sludge-amended soil is not expected to occur.
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) = 0.21 ug/g DW
See Section 3, p. 3-2.
3-5
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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:
Wheat 7.8 ug/g tissue DW (kg/ha)"1
Human diet:
Wheat 7.8 ug/g tissue DW (kg/ha)"1
The only data available for direct calculation
of uptake slopes were from studies in which Se
was applied in a culture solution (Rosenfeld
and Beath, 1964; see Table 4-2). These studies
are of limited value in predicting uptake from
sludge-amended soil because a chemical is
usually much more highly available to plant
roots when in solution than when applied to
soil. To calculate a slope in units of Ug/g
tissue DW (kg/ha)"1, it is necessary to assume
that the amount of Se present in a unit volume
of solution is equal to the amount present in
an equal volume of soil. If this assumption is
made, then 1 mg/L of Se in nutrient solution is
equivalent to a Se loading of 1.5 kg/ha.
Slopes calculated from culture solution data
(Table 4-2) and adjusted by a factor of 1.5 are
21.2 for corn grain, 32.3 for alfalfa, and
range from 16 to 107 for wheat, varying
inversely with solution sulfur concentration.
Since the assumptions involved in applying data
from culture solution to the field are unsup-
ported, available information from several
sources was used to indirectly compute uptake
slopes from field data. Yopp et al. (1974)
report that Se content of seleniferous soils
normally ranges from 1.0 to 6.0 Ug/g« Taking
the geometric midpoint of this range
(2.45 Ug/g)> subtracting the background concen-
tration (0.21 Ug/g) and applying the conversion
factor, CO, stated above, an application rate
of 4.5 kg/ha is estimated to represent seleni-
ferous soils. The following ranges are given
by the National Academy of Sciences (NAS)
(1983) for background concentrations of Se in
wheat, alfalfa meal, and corn used as animal
feeds: 0.01 to 3.0, 0.01 to 2.0, and 0.1 to
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1.0, respectively, in Ug/g on an as-fed basis.
Maximum Se content for these crops on seleni-
ferous soils were 30, 10, and 20 pg/g, respec-
tively (Rosenfeld and Beath, 1964). Assuming
an approximate 15% moisture content for each
feedstuff (based on values for wheat and field
corn in U.S. Department of Agriculture (USDA),
1975), and taking the geometric midpoint of
each background concentration range, but using
maximum values for crop content from selenifer-
ous soils, the following maximum uptake slopes
are obtained, in Ug/8 tissue DW (kg/ha)"1:
wheat, 7.8; alfalfa, 2.6; and corn, 5.2. These
indirectly computed slopes are considered more
reliable than those derived from culture solu-
tion studies. The highest of these slopes,
that for wheat, will be used to represent all
crops in both the human and animal diets.
v. Background concentration in plant tissue (BP)
Animal diet:
Wheat 0.20 ug/g DW
Human diet:
Wheat 0.20 Ug/g DW
The median background concentration of Se in
wheat was reported to be (J.16 Ug/g WW by Wolnik
et al. (1983). This value agrees well with
that derived from NAS (1983), 0.17 ug/g WW, as
derived above. Applying a correction for 15%
moisture content, a value of 0.20 Ug/g DW is
obtained. (See Section 4, p. 4-5.)
Index 5 Values
Sludge Application
Rate (mt/ha)
Sludge
Diet Concentration 0 5 50 500
Animal
Typical
Worst
1.0
1.0
1.2
1.9
2.7
9.8
15
73
Human Typical 1.0 1.2 2.7 15
Worst 1.0 1.9 9.8 73
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 - The concentration of Se in
tissues of plants grown in sludge-amended soil is
3-7
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expected to increase above background by a factor
ranging from 1.2 when typical sludge is applied at
5 mt/ha to 73 when the worst sludge is applied at
500 mt/ha. These factors apply for plants in animal
and human diets.
Index of Plant Concentration Increment Permitted by
Phytotozicity (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:
Wheat 429 ug/g DW
Human diet:
Tomato 191 Ug/g DW
Yopp et al. (1974) reported that concentrations
of 380 Ug/g Se in wheat was not accompanied by
injury to the plant. Rosenfeld and Beath
(1964) reported the appearance of chlorosis in
wheat containing 322 Ug/g DW when grown in low-
sulfur culture solutions, but no effect was
noted for wheat containing 328 to 396 Ug/g DW
when grown in culture solutions containing
higher sulfur concentrations. Since all wheat
containing Se concentrations of 429 Ug/g DW Se
or .more showed signs of chlorosis, this value
was chosen to represent the tissue
concentration associated with phytotoxicity for
. wheat. Yopp et al. (1974) reported that a
concentration of 191 Ug/g DW in tomatoes was
accompanied by growth reduction and visual
symptoms of Se phytotoxicity. Tomatoes were
chosen because both background concentration
and a concentration associated with toxicity
were available. (See Section 4, p. 4-12.)
3-8
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ii. Background concentration in plant tissue (BP)
Animal diet:
Wheat 0.20 ug/g DW
Human diet:
Tomato 0.2 Ug/g DW
The value for wheat was based on a study by
Wolnik et al. (1983) (see Section 3, p. 3-7).
Rosenfeld and Beath (1964) reported minimum and
maximum concentrations of Se in tomatoes grown
in Se contaminated areas. The value chosen is
the minimum concentration, since the soils con-
tain higher Se concentrations than normal
soils. (See Section 4, p. 4-5.)
d. Index 6 Values
Plant Index Value
Wheat 2100
Tomato 960
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 expected factor
for the increase of Se in plant tissues is not
expected to be precluded 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.
r
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.
3-9
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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) =
0.20 pg/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) = 7 Ug/g DW
Swine fed 7 Ug/g DW Na2SeC>3 for 108 days showed
decreased weight gain, cracked hooves, hair
loss and emaciation (Wahlstrom et al., 1956 in
NAS, 1980). (See Section 4, p. 4-16.)
d. Index 7 Values
Sludge Application Rate (mt/ha)
Sludge
Concentration 0 5-50 500
Typical
Worst
0.029
0.029
0.034
0.054
0.078
0.28
0.43
2.1
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 - A hazard due to Se may
exist for animals which feed on plants grown in
sludge-amended soil only when the worst sludge is
applied at a high cumulative rate (500 mt/ha).
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
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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 tor comparison.
Data Used and Rationale
i. Sludge concentration of pollutant (SC)
Typical 1.111 Ug/g DW
Worst 4.848 Ug/g DW
See Section 3, p. 3-2.
ii. Background concentration of pollutant in soil
(BS) = 0.21 Ug/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 (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 nit/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-
3-11
-------
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
(TA) = 7 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 0.0015 0.0079 0.0079 0.0079
Worst 0.0015 0.035 0.035 0.035
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 - No hazard due to Se is
expected for animals which incidentally ingest
sludge-amended soil while grazing.
Effect on Humans
1. 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. 3-7).
3-12
-------
ii. Background concentration in plant tissue (BP) =
0.20 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 46.3
Adult 110.7 ug/day
The Food and Drug Administration (FDA) Total
Diet Studies reported that the average daily
intake of Se for adults was 110.7 Ug/day in
fiscal year (FY) 1977 based on market basket
studies representing major food groups and bev-
erages (FDA, 1980a). Values for the three pre-
vious years were slightly higher with Se
intakes of 169.0, 169.7, and 135.6 ug/day in FY
1974, FY 1975, and FY 1976, respectively. The
value for FY 1977 was chosen to represent the
most current data available. MAS (1983)
reported a similar Se intake value of
132 ug/day for the state of Maryland. In a
comparison study of toddler and infant diets,
FDA reported that the average daily intake of
Se for toddlers was 46.3 Ug/day in FY 1977
(FDA, 1980b). Intake values for FY 1975 and FY
1976 were 58.4 and 45.0 ug/day, respectively.
As for adults, the value for FY 1977 was
selected to represent the most current data
available. (See Section 4, p. 4-4.)
3-13
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v. Acceptable daily intake of pollutant (ADI) =
455 Ug/day
An ADI of 455 Ug/day was recommended by
U.S. EPA (1984b).. This value, was chosen based
on a study by Bowen (1966) in which young mon-
keys were exposed to drinking water containing
1 ppm Se for 5 years to study the impact of a
low level of Se on the formation of dental
caries. Carious lesions developed more often
and faster in Se-treated monkeys than in con-
trols. Assuming a weight of 3.5 kg for monkeys
and consumption of 450 mL water/day, an intake
of 0.13 mg/kg/day was calculated. Multiplying
the intake rate by 70 kg, the assumed average
human weight, and dividing by an uncertainty of
20 (a factor of 5 for interspecies extrapola-
tion, a factor of 2 to protect sensitive popu-
lations, and a factor of 2. to convert from
LOAEL to NOAEL), the resulting ADI was
455 pg/person/day. (See Section 4, p. 4-7.)
d. Index 9 Values
Sludge Application
Rate (mt/ha)
Sludge
Group Concentration 0 5 ' 50 500
Toddler
Typical
Worst
0.10
0.10
0.11
0.13
0.16
0.39
0.56
2.5
Adult Typical 0.24 0.26 0.40 1.5
Worst 0.24 0.32 1.0 6.8
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 - A health hazard due to Se
from consumption of plants grown in sludge-amended
soil is expected for toddlers only when sludge with
a high Se concentration is applied at a high rate
(500 mt/ha) and for adults when typical or worst-
case sludge is applied at a high rate (500 mt/ha).
3-14
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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
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.
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) =
0.20 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)
= 3.75 ug/g tissue DW (ug/g feed DW)"1
The only available data on tissue uptake in
species consumed by humans are for swine (NAS,
1980; see Section 4, p. 4-18). Changes- in
dietary Se from sodium selenite or natural Se
content gave similar uptake slopes in muscle
tissue (0.9 and 1.05 Ug/g tissue WW (ug/g feed
DW)"1); liver and kidney slopes were lower. In
the only other study where both muscle and
liver were examined, a study with guinea pigs
fed-Swiss chard (Furr et al., 1976), the liver
slope was about 5 times higher than the muscle
slope (10.1 and 2.07 Ug/g tissue DW (ug/g feed
DW)"1, respectively). However, the range of
feed concentrations was too narrow (0.05 to
0.08 Ug/g DW) not to cast doubt on the
3-15
-------
meaningfulness of the results. Therefore, the
highest value for swine muscle is chosen as the
most conservative and realistic value to
represent meats in the human diet. To convert
the wet-weight slope to a dry-weight basis, a
moisture content of 28 percent was assumed.
Thus, 1.05 divided by 0.28 yields 3.75 Ug/g
tissue DW (ug/g feed DW).
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 composition 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 46.3 Ug/day
Adult 110.7 Ug/day
See Section 3, p. 3-13.
. vi. Acceptable daily intake of pollutant (ADI) =
455 ug/day
See Section 3, p.3-14.
d. Index 10 Values
V ^
Sludge Application
Rate (mt/ha)
Sludge
Group Concentration 0 5 50 500
Toddler
Typical
Worst
0.10
0.10
0.12
0.18
0.25
0.84
1.3
6.2
Adult Typical 0.24 0.28 0.62 3.3
Worst 0.24 0.44 2.2 16
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - Consumption of animal
products derived from animals which had fed on
3-16
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plants grown in sludge-amended soil is expected to
pose a health hazard due to Se for toddlers when
typical and worst-case sludge is applied at a high
rate (500 mt/ha), and for adults when typical sludge
is applied at a high rate (500 mt/ha) and when the
worst-case sludge is applied at 50 mt/ha or greater.
3. Index of Human Tozicity 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 = Swine muscle
See Section 3, p. 3-15.
ii. Background concentration of pollutant in soil
(BS) = 0.21 pg/g. DW
See Section 3, p. 3-2.
iii. Sludge concentration of pollutant (SC)
Typical 1.111 Ug/g DW
Worst 4.848 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.
3-17
-------
v. Uptake slope of pollutant in animal tissue (UA)
= 3.75 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 35.95 g/day
Adult 104.3 g/day
These intake values are for meat only (beef,
pork, lamb, and veal), based on data from
Pennington (1983). This is a slightly more
limited choice than that for Index 10 because
only grazing animals are considered.
vii. Average daily human dietary intake of pollutant
(DI)
Toddler 46.3 Ug/day
Adult 110.7 ug/day
See Section 3, p. 3-13.
viii. Acceptable daily intake of pollutant (ADI) =
455 Ug/day
See Section 3, p. 3-14.
Index 11 Values
Sludge Application
Rate (mt/ha)
Group
Toddler
Adult
Sludge
Concentration
Typical
Worst
Typical
Worst
0
0.10
0.10
0.25
0.25
5
0.12
0.17
0.29
0.45
50
0.12
0.17
0.29
0.45
500
0.12
0.17
0.29
0.45
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - No human health hazard due
to Se is expected from consumption of animal pro-
ducts derived from animals which had incidentally
ingested sludge-amended soil while grazing.
4. 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 ADI.
3-18
-------
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 ' 1.111 Ug/g DW
Worst A. 848 Ug/g DW
See Section 3, p. 3-1.
iii. Background concentration of pollutant in soil
(BS) = 0.21 ug/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 (1984a).
v. Average daily human dietary intake of pollutant
(DI)
Toddler 46.3 Ug/day
Adult 110.7 ug/day
See Section 3, p. 3-13.
vi. Acceptable daily intake of pollutant (ADI) =
455
See Section 3, p. 3-14.
3-19
-------
d. Index 12 Values
Sludge Application
Rate (mt/ha)
Group
Toddler
Adult
e.
f.
Sludge
Concentration 0
Typical
Worst
Typical
Worst
0.10
0.10
0.24
0.24
Value Interpretation -
Preliminary
Conclusion
0.
0.
0.
0.
Same
5
10
10
24
24
50
0.
0.
0.
0.
as for
- No
human
10
11
24
24
Index
500
0.
0.
0.
0.
9
health
11
11
24
24
Pure
Sludge
0.
0.
0.
0.
hazard
11
16
24
24
due
to Se is expected when either sludge-amended soil or
pure sludge is ingested.
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.
c. Data Used and Rationale - As described for Indices 9
to 12.
d. Index 13 Values
Sludge Application
Rate (mt/ha)
Group
Toddler
Adult
Sludge
Concentration
Typical
Worst
Typical
Worst
0
0.11
0.11
0.25
0.25
5
0.14
0.28
0.35
0.73
50
0.32
1.2
0.82
3.2
500
1.8
8.6
4.6
23
e. Value Interpretation - Same as for Index 9.
f. Preliminary Conclusion - The aggregate amount of Se
in the human diet resulting from landspreading of
sludge is expected to pose a health hazard when
sludge containing a typical concentration of Se is
applied at a high rate or when sludge containing a
high concentration or Se is applied at a rate of
50 mt/ha or greater.
3-20
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II. LANDFILLING
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
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.
3-21
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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., Kj values) are con-
sidered the best available for analysis of
metal transport from landfilled sludge. The
same soil types are also used for nonmetals for
convenience and consistency of analysis.
(b) Dry bulk, density (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. (CDM),
1984).
(c) Volumetric water content (9)
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 Che wacer flux
estimated by infilcration or net recharge. The
volumetric water content is used in calculating
the water movement through Che 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 Che Uniced States and
estimated time of landfill leaching to be 4 or
5 years. Other types of landfills may leach
3-22
-------
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 5m 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)
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, 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
3-23
-------
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 1.111 mg/kg DW
Worst 4.848 mg/kg DW
See Section 3, p. 3-1.
(b) Degradation rate (u) = 0 day~l
The degradation rate in the unsaturated zone is
assumed to be zero for all inorganic chemicals
(c) Soil sorption coefficient (Kj)
Typical 14.9 mL/g
Worst 5.91 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.
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 (#)
Typical 0.44 (unitless)
Worst 0.389 (unitless)
3-24
-------
Porosity is that portion of the total volume of
soil that is made up of voids (air) and water.
Values corresponding to the above soil types
are from Pettyjohn et al. (1982) as presented
in U.S. EPA (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 (unltLess)
Worst .0.02 (unitless)
The hydraulic gradient is the slope of the
water table in an unconfined aquifer, or the
piezbmetric 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 (Ai)
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.
3-25
-------
(c) Dispersivity coefficient (a)
Typical 10 m
Worst 5 ra
These values are 10 percent of the distance
from well to landfill (AS,), 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 m^.
iii. Chemical-specific parameters
(a) Degradation rate (ji) = 0 day"*
Degradation is assumed not to occur in the
saturated zone.
(b) Background concentration of pollutant in
groundwater (BC) = 8 Ug/L
No information was available on the concentra-
tion of Se in groundwater. Taylor (1963 as
cited in NAS, 1977) reported that the mean Se
concentration from 194 samples of finished
drinking water was 8 Ug/L. It is assumed that
groundwater concentrations are equal to or less
than this value. (See Section 4, p. 4-3.)
(c) Soil sorption coefficient (K
-------
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 - An increase in the concentration
of Se in groundwater at the well due to leaching from a
sludge landfill is expected when worst-case conditions
occur for the site parameters only, and for all
parameters simultaneously.
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 Section 3, p. 3-28.
b. Background concentration of pollutant in groundwater
(BC) = 8 pg/L
See Section 3, p. 3-26.
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)
= 110.7 Ug/day
See Section 3, p. 3-13.
e. Acceptable daily intake of pollutant (ADI)
455 Ug/day
See Section 3, p. 3-14.
4. Index 2 Values - See Table 3-1.
5. Value Interpretation - Value equals factor by which pol-
lutant intake exceeds ADI. Value >1 indicates a possible
3-27
-------
TABLE 3-1. INDEX OF GROUNDWATER CONCENTRATION INCREMENT RESULTING FROM LANDFILLED SLUDGE (INDEX 1) AND
INDEX OF HUMAN TOXICITY RESULTING FROM GROUNDWATER CONTAMINATION (INDEX 2)
Site Characteristics
Condition of
34
Co
I
00
Sludge concentration T
Unsaturated Zone
Soil type and charac- T
teristics^
Site parameters6 T
Saturated Zone
Soil type and charac- T
teristics^
Site parameters** T
Index 1 Value 1.0
Index 2 Value 0.24
W
4
T
T
T
T
1.0
0.24
T
W
T
T
T
1.0
0.24
NA
W
T
T
1.0
0.24
T
T
W .
T
1.0
0.24
T
T
T
W
1.2
0.25
W
NA
W
W
W
4.5
0.37
N
N
N
N
0
0.24
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) an(* 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).
SHydraulic gradient (i), distance from well to landfill (Aft,), and dispersivity coefficient (a).
-------
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 - No human health risk due to Se
in groundwater at the well is expected when sludge is
disposed of in a landfill.
III. INCINERATION
A. Index of Air Concentration Increment Resulting from
Incinerator Emissions (Index 1)
1. Explanation - Shows the degree of elevation of the
pollutant concentration in the air due to the incinera-
tion of sludge. An input sludge with thermal properties
defined by the energy parameter (EP) was analyzed using
the BURN model (CDM, 1984). This model uses the thermo-
dynamic and mass balance relationships appropriate for
multiple hearth incinerators to relate the input sludge
characteristics to the stack gas parameters. Dilution
and dispersion of these stack gas releases were described
by the U.S. EPA's Industrial Source Complex Long-Term
(ISCLT) dispersion model from which normalized annual
ground level concentrations were predicted (U.S. EPA,
1979). The predicted pollutant concentration can then be
compared to a ground level concentration used to assess
risk.
2. Assumptions/Limitations - The fluidized bed incinerator
was not chosen due to a paucity of available data.
Gradual plume rise, stack tip downwash, and building wake
effects are appropriate for describing plume behavior.
Maximum hourly impact values can be translated into
annual average values.
3. Data Used and Rationale
a. Coefficient to correct for mass and time units (C) =
2.78 x 10~7 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:
3-29
-------
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 (1838F)
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 - 26.6%
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 1.111 mg/kg DW
Worst 4.848 mg/kg DW
See Section 3, p. 3-1.
d. Fraction of pollutant emitted through stack (FM)
Typical 0.01 (unitless)
Worst ' 0.026 (unitless)
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 (COM,
1983).
e. Dispersion parameter for estimating maximum annual
ground level concentration (DP)
Typical 3.4
Worst 16.0
The dispersion parameter is derived from the U.S.
EPA-ISCLT short-stack model.
3-30
-------
f. Background concentration of pollutant in urban air
(BA) = 0.0009 Ug/m3
An average of 0.09 Ug of Se per 100 m3 of air was
reported in seven samples taken during the summer in
Cambridge, Massachusetts (Lakin, 1973). Se levels
in atmospheric dust collected on air conditioning
filters in 10 U.S. cities ranged from 0.05 to
10 Ug/g (Lakin, 1973); however, no information was
given on the air concentration. (See Section 4,
p. 4-3.)
4. Index 1 Values
Sludge Feed
Fraction of Rate (kg/hr DW)a
Pollutant Emitted Sludge
Through Stack Concentration 0 2660 10,000
Typical
Typical
Worst
1.0
1.0
1.0
1.1
1.5
3.4
Worst Typical 1.0 1.1 2.4
Worst 1.0 1.4 7.2
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 - The concentration of Se in air
is expected to moderately increase above background
levels when sludge is incinerated.
B. Index of Human Toxicity Resulting from Inhalation of
Incinerator Emissions (Index 2)
1. Explanation - Shows the increase in human intake expected
to result from the incineration of sludge. For noncar-
cinogens, levels typically were derived from the American
Conference of Governmental and Industrial Hygienists
(ACGIH) threshold limit values (TLVs) for the workplace.
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.
3-31
-------
3. Data Used and Rationale
a. Index of air concentration increment resulting from
incinerator emissions (Index 1)
See Section 3, p. 3-31.
b. Background concentration of pollutant in urban air
(BA) = 0.0009 Ug/m3
See Section 3, p. 3-31.
c. Maximum permissible intake of pollutant by
inhalation (MPIH) = 70 yg/day
U.S. EPA (1984b) reported an MPIH of 0.07 mg/day.
This value was derived based on results of a study
by Glover (1967). This study reported that a uri-
nary concentration of 0.1 Ug/L in workers exposed to
atmospheric Se corresponded roughly to an air con-
centration of 0.1 mg/m3. Assuming a worker inhaled
10 m3 of air during a workday, this exposure corres-
ponds to a daily intake of 1 mg/day during a 5-day
work week. The MPIH was derived by multiplying by
5/7 to expand exposure to a 7-day week and dividing
by an uncertainty factor of 10 to protect sensitive
populations. No health effects were reported to be
associated with the level reported by Glover (1967).
(See Section 4, p. 4-8.)
d. Exposure criterion (EC) = 3.5 Ug/m3
The exposure criterion is the level at which the
inhalation of the pollutant is expected to exceed
the acceptable daily intake Level for inhalation.
The exposure criterion is calculated using the
following formula:
Ec = MPIH
20 m3/day
3-32
-------
4. Index 2 Values
Fraction of
Pollutant Emitted Sludge
Through Stack Concentration
Sludge Feed
Rate (kg/hr DW)a
2660 10,000
Typical
Worst
Typical 0.00026 0.00027 0.00040
Worst 0.00026 0.00029 0.00087
Typical 0.00026 0.00028 0.00062
Worst 0.00026 0.00035 0.0019
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 intake exceeds MPIH. Value >1 indicates a pos-
sible human health threat. 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 - A human health hazard due to the
release of Se into air when sludge is incinerated is not
expected to occur.
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.
3-33
-------
SECTION 4
PRELIMINARY DATA PROFILE FOR SELENIUM IN MUNICIPAL SEWAGE SLUDGE
I. OCCURRENCE
A. Sludge
I. Frequency of Detection
Detected in 335 of 431 samples from
40 POTWs (78%)
Detected in 58 of 81 samples from
10 POTWs (72%)
2. Concentration
In 335 out of 431 samples from
40 POTWs Se values ranged from 1 to
140,000 Ug/L.
Median = 1.111 ug/g DW
95th percentile = 4.848 Ug/g DW
In 58 out of 81 samples from 10 POTWs,
Se values ranged from 2 to 1718 Ug/L.
Summary of sludge analysis from 74
cities in Missouri (ug/L).
Min. Max. Mean Median
U.S. EPA, 1982
(p. 41)
U.S. EPA, 1982
(p. 49)
U.S. EPA, 1982
(p. 41)
Statistically
derived from
sludge concen-
tration data
presented in
U.S. EPA, 1982
U.S. EPA, 1982
(p. 49)
Clevenger et
al., 1983
(p. 1472)
25
3.9
Metro Denver anaerobically digested
sludge mean =2.5 Ug/g DW
Louisville, KY sludge: 20 to 37 Ug/g
Largo, FL sludge: 12 to 15 Ug/g
1.7 to 8.7 ug/g (DW)
Baxter et al.,
1983 (p. 313)
Jones and Lee,
1977 (p. 313)
Furr et al., .
1976 (p. 684)
4-1
-------
Soil - Unpolluted
1. Frequency of Detection
Se is widely but unevenly distributed.
2. Concentration
"Normal" mean 0.5 Ug/g
range 0.1 to 2.0
Garden soil 0.21 yg/g (DW)
Range for most soils 0.1 to 0.2 ug/g
and the average may be as low as
0.01
Seleniferous soils range
1.0 to 6.0 Ug/g with high of 82 Ug/g
Water - Unpolluted
1. Frequency of Detection
In an analysis of 194 public water
supply sources, Se was "barely
detectable" in most samples.
In a seleniferous area of South Dakota,
no Se was detected in 34 out of
44 wells.
2. Concentration
a. Freshwater
y
"...surface water generally con-
tains less than 10 Ug/L of Se."
Freshwater levels average 20
Average Se content of nine
rivers is given as 0.2 Ug/L.
Range: 0.114 to 0.348 ug/L.
14 out of 43 surface water samples
from Colorado contained Se at
levels ranging from 10 to 400
Ug/L. Eleven of the samples
exceeded 10 Ug/L allowable in
drinking water.
Jenkins, 1980a
(p. 34)
Allaway, 1968
(p. 242)
Cappon, 1984
(p. 100)
Yopp et al.,
1974 (p. 198)
Yopp et al.,
1974 (p. 198)
NAS, 1983
(p. 28)
NAS, 1983
(p. 28)
Harr, 1978
(p. 395)
Jenkins, 1980a
(p. 15)
Lakin, 1973
(pp. 102 and
104)
Lakin, 1973
(p. 102)
4-2
-------
D. Air
Water in lakes, including those
in seleniferous areas, has been
found to contain very little Se.
Seawater
27 seawater samples, worldwide,
contained an average of
0.09 yg/L.
Range: 0.052 to 0.13 Ug/L.
Drinking Water
8 Ug/L in public finished
drinking water (mean of 194
samples)
Se occurs as a minor constituent
in drinking water in a concentra-
tion range of 0.1 to 100 Ug/L.
Upper limit for Se in drinking
water is 10 Ug/L.
Frequency of Detection
The atmosphere is supplied with Se via
soil dust, volcanoes, burning of fos-
sil fuels, industrial emissions and
volatile products produced by plants
and animals.
Concentration
0.05 to 10 Ug/g Se found in atmo-
spheric dust collected on air condi-
tioning filters in 10 U.S. cities.
7 air samples from Cambridge, MA con-
tained an average of 0.9 ng/nr* Se
in 1965.
NAS, 1983
(p. 29)
Lakin, 1973
(p. 105)
Taylor, 1963 in
NAS, 1977
NAS, 1983
(p. 28)
NAS, 1983
NAS, 1983
(p. 39)
Lakin, 1973
(p. 106)
Lakin, 1973
(p. 106)
4-3
-------
B. Food
1. Total Average Intake
Estimated human daily intake from
diet
Food
Selenium Intake
(Ug/day)
Plant
Vegetables, fruit
sugars
Cereals
Animal
Dairy products
Meat, fish
Total
5.4
44.5
13.5
68.6
132.0
Average Daily Se Intake - Adults
FY 1977 - 110.7 Ug/day
FY 1976 - 135.6 Ug/day
FY 1975 - 169.7 Ug/day
FY 1974 - 169.0 Ug/day
Average Daily Se Intake - Toddlers
FY 1977 - 46.3 Ug/day
FY 1976 - 45.0 Ug/day
FY 1975 - 58.4 Ug/day
Concentration
Higher Se values may be expected in
plant-derived foods that are high in
protein and from seleniferous regions,
Se in food from seleniferous regions
(Ug/g):
NAS, 1983
(p. 36)
FDA, 1980a
FDA, 1980b
NAS, 1983
(p. 30)
NAS, 1983
(p. 30)
Bread
Milk
Eggs
Meat
Vegetables
0.25 to 1.0
0.16 to 1.27
0.25"to 1.27
1.17 to 8.0 (DW)
2 to 100
U.S. EPA, 1980
(p. C-l)
4-4
-------
Selenium content in grains and vegetables grown in
seleniferous areas
Rosenfeld and
Beath, 1964
(p. 106)
Wheat
Corn
Rye
Onions
Barley
Oats
Asparagus
Rutabagas
Selenium (ppm)
Minimum Maximum
Selenium (ppm)
Minimum Maximum
1.15 30.0 Cabbage 2.3 4.5
1.00 20.0 Peas and beans 0.2 2.0
0.90 25.0 Carrots
0.40 17.8 Tomatoes
1.70 17.0 Beets
2.00 15.0 Potatoes
2.70 11.0 Cucumbers
1..70 6.0
1.3 1.4
0.2 1.2
0.3 1.2
0.2 0.9
0.1 0.6
Se in food from nonselenif erous HAS, 1983
regions (ug/g): (pp. 30 to 33)
Milk 0.010 to
Butter & cream 0.003 to
Cheese 0.010 to
Eggs 0.20 to
Bread 0.28 to
Beef, chicken, lamb
Trout
Shrimp
Shellfish
Fish
Fruits & vegetables
Cucumbers, carrots, 0.015 to
onions
Mushrooms & garlic 0.060 to
0.021
0.006
0.123
0.52
0.68
0.22
0.36
2
0.63
0.63
<0.01
0.140
0.249
Se in selected vegetables (ug/g WW)
Mean Median Minimum Maximum
Wheat
Lettuce
Peanuts
Potatoes
Soybeans
Sweet
corn
6.37
0.
0.
0.
0.
0.
0016
057
003
19
0064
0
0.
0.
0.
0.
0.
.16a
00066
036
Oil
75
0028
<0
<0.
0.
<0.
0.
.010
0004
002
002
010
<0.002
6000
0.011
0.91
0.055
2.5
0.086
Wolnik et
al., 1983
a Wet Weight factor = 0.883
4-5
-------
Variation of selenium concentrations in NAS, 1983
various feed ingredients (as-fed basis) in (p. 27)
the United States
Ingredient Selenium (ppm)
Alfalfa meal
Barley
Bentonite
Blood meal
Brewers' grains
Corn
Dicalcium phosphate
Feather meal
Fish meals
Gluten food
Gluten meal
Linseed meal
Meat meal
Oats
Poultry by-product
Rapeseed meal
Soybean meal
Whole soybeans
Wheat
Wheat middlings
Wheat bran
0.01-2.00
0.05-0.50
1.00-20.00
0.15-1.00
0.01-1.00
0.15-1.00
1.00-5.00
0.15-0.50
0.10-1.50
0.50-1.20
0.08-0.50
0.01-1.00
0.50-1.00
0.06-1.00
0.07-0.90
0.01-3.00
0.15-1.00
0.10-3.00
II. HUMAN EFFECTS
A. Ingestion
1. Carcinogenicity
a. Qualitative Assessment
Se is reported to be carcinogenic Jenkins, 1980a
and teratogenic to animals.
Available data on Se carcinogeni- U.S. EPA, 1980
city are considered to be inade- (p. C-61)
quate to use carcinogenic risk as
a basis for health criteria. In
addition, there is evidence that
Se has anticarcinogenic effects
in animals and man.
Potency
Data not available.
4-6
-------
c. Effects
Malignant tumors such as spindle U.S. EPA, 1980
cell sarcoma, leukemia types, (p. C-45)
pleomorphic carcinoma found in
selenate-supplemented animals.
2. Chronic Toxicity
a. ADI
455 Ug/day U.S. EPA, 1984b
b. Effects
Reported to cause the disease of Browning, 1969
"blind staggers" and "Alkali
disease" in cattle.
Lethal to animal when high dosages Fishbein, 1977
are administered.
1 ppm Se in drinking water for 5 Bowen, 1966
years produced an increase in num-
ber of dental caries in monkeys.
Chronic effects to animals include Fishbein, 1977
liver damage in the form of atro-
phy, necrosis, cirrhosis, hemorrage,
and progressive anemia.
3. Absorption Factor
80 percent U.S. EPA, 1980
(p. C-9)
4. Existing Regulations
Water quality criterion = 10 Ug/L U.S. EPA, 1980
(p. C-67)
B. Inhalation
1. Carcinogenicity
a. Qualitative Assessment
No evidence of carcinogenesis
induced by Se inhalation
4-7
-------
2. Chronic Toxicity
a. Inhalation Threshold or MPIH
Threshold limit value for Se con-
centrations in air for a normal
8-hour workday is 0.2 mg/m^
The limit is 0.0035 mg/m3
ambient air concentration.
MPIH = 0.07 mg/day
b. Effects
Marked irritation of the nasal
conjuactival, and tracheobronchial
mucose occurs, leading to ceryh,
wheezing, dyspnea, chemical pneum-
onitis, and pulmonary edema.
3. Absorption Factor
0.1 Ug/L in urine of workers exposed
to Se in air corresponded to atmo-
spheric concentration of 0.1
80 percent
4. Existing Regulations
Recommended TWA-TLV of 0.2 mg/m3 Se
for Se hexafluoride was established.
III. PLANT EFFECTS
ACGIH, 1977
U.S. EPA, 1984b
U.S. EPA, 1984b
U.S. EPA, 1980
U.S. EPA, 1980
U.S. EPA, 1980
(p. C-9)
ACGIH, 1983
Phytotoxicity
1.8 ppm Se in soil solution severely affected Yopp et al.,
the majority of crops of economic importance 1974 (p. 200)
in Illinois and is the recommended maximum
permissible level.
See Table 4-1.
B. Uptake
to
Primary Se accumulator plants require 1
50 Ug/g Se in either soil or water for
growth and may contain 100 to 10,000 Ug/g
Se as a glutamyl depeptide or salenocystan-
thionine. Primary accumulator plants
include species of the genera Astragalas
Harr and Muth,
1972 (p. 177)
4-8
-------
(24 species can contain 1000 Ug/g Se),
Oonoposis (800 Ug/g Se), Stanelya
(700 ug/g Se), Zylorhiza (120 Ug/g Se),
and Machaeranthera. Secondary accumulator
plants grow in either seleniferous or non-
seleniferous soil and contain 25 to
100 Ug/g Se: Astor (72 Ug/g Se),
Gutierrezia (60 Ug/g Se), Atriplex
(50 ug/g Se), Grindelia (38 Ug/g Se),
Castilleja and Comandra. Nonaccumulator
plants growing in seleniferous soils contain
1 to 25 ug/g Se.
The form in which Se occurs often deter-
mines the amount accumulated. A greater
uptake of Se by corn (1000 ug/g) and other
crop plants occurs when Se is added as an
organic rather than the selenite ion.
Accumulation in wheat is greater
(1000 Ug/g) in the presence of selenate
rather than selenite.
See Table 4-2.
IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS
A. Toxicity
Highly toxic >4 to 5 Ug/g in animal diets
generally resulted in depressed growth
rates, infertility of eggs or other
undesirable effects.
0.054 to 0.084 Ug/g threshold dietary con-
centration. Intake-below, Se is conserved;
intake above, Se is excreted in proportion
to intake.
In general, 1 to 5 Ug/kg of body weight
required to produce acute toxicity in
animals.
5 to 40 Ug/g "guideline of toxic exposure"
to Se in natural feed stuffs; 6 to 8 Ug/g
minimal dietary lethal dose in semi-
purified feeds.
5 to 10 ug/g Se in forages causes naturally
occurring Se poisoning.
0.1 to 0.3 Ug/g (DW) in diet, is dietary
requirement for Se.
Yopp et al.,
1974
Allaway, 1968
(p. 262)
Harr, 1978
(pp. 369 to 387)
Ewan, 1978
(p. 447)
Harr, 1978
(p. 407)
Rosenfeld and
Beath, 1964
NAS, 1980
(p. 400)
4-9
-------
B.
2 Ug/g (DW) maximum tolerable limit for
all species
See Table 4-3.
Uptake
0.02 to 2.0 JJg/g (WW) in liver, kidney of
35 species of mammals
NAS, 1980
(p. 400)
Jenkins, 1980a
(p. 151)
0.02 to 4.0 Ug/g (WW) in liver of 8 species Jenkins, 1980a
of birds
0.28 to 0.42 ug/g (WW) muscle of cow
0.18 Ug/g (WW) liver of cow
1.70 Ug/g (WW) kidney of cow
0.48 Ug/g (WW) milk of cow
Se concentrations in the muscle on
Se deficient natural diets
Feed (ug/g DW) Muscle (ug/g WW)
(p. 151)
Jenkins, 1980b
(p. 1091)
NAS, 1980
(p. 339)
0.027 to 0.493 0.034 to 0.521
See Table 4-4.
V. AQUATIC LIFE EFFECTS
Data not immediately available.
VI. SOIL BIOTA EFFECTS
Data not immediately available.
VII. PHYSICOCHEMICAL DATA FOR ESTIMATING FATE AND TRANSPORT
Atomic wt: 78.96
Density: 4.28 to 4.81
Solubility
sodium selenates: very soluble
silver selenates: 16 to 33 mg/L
heavy metal selenates: insoluble
Melting point (°C)
Se: 170 to 217
H2Se: -66
Boiling point (°C)
Se: 684 to 688
H2Se: -41
Distribution constant (K^, mL/g)
Sandy loam soil
range: 8.89 to 25.0
mean: 14.9
U.S. EPA, 1980
(p. A-l)
Lakin, 1973
(p. 98)
Gerritse et al.,
1982
4-10
-------
Sandy soil
range: 2.97 to 11.8
mean: 5.91
Se is oxidized to selenite and is bound in a Lakin, 1973
very insoluble basic ferric selenite and is (p. 99)
immobile.
Se is quantitatively precipitated as a basic Lakin, 1973
ferric selenite at pH 6.3 to 6.7. At a pH of (pp. 102 to 103)
about 8, selenite may be oxidized to the soluble
selenate ion.
4-11
-------
TABLE 4-1. PHYTOTOXICITY OF SELENIUM
Plant/Tissue
Soybean
Corn
Wheat
Wheat
Wheat
Millet
Buckwheat
i
>- Alfalfa
ho
Clover
Wheat
Tomato
Wheat
Wheat
Wheat
Wheat
Chemical
Form
Applied
NR°
NR
Selenite
NR
NR
Selenate
Selenite
Selenite
Selenite
NR
NR
Na2Se(>4
Na2SeO^
NaoSeOA
Na2SeO<,
Growth
Medium
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Control
Tissue
Concentration
(Ug/g DW)
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
0
0
0
0
Experimental Experimental
Soil Application
Concentration8 Rate
((ig/g DW) (kg/ha)
2.
2.
5.
2.
3.
1.
2.
2.
2.
NR
25 (1.8)
5 (2.0)
0 (.40)
5 (2.0)
75 (3.0)
12 (0.9)
5 (2.0)
25 (1.8)
25 (1.8)
NR
(2.0)^
(4.0)e
(12.0)8
(824. 0)h
NAC
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Experimental
Tissue
Concentration'
(Mg/g DW) Effect
NR
NR
NR
NR
NR
NR
NR
NR
NR
380
191
322
429
538
1004
Leaf chlorosis,
. stem tumors, leaf
lesions
Reduced foliage
Leaf chlorosis,
reduction
Leaf chlorosis
Leaf chlorosis,
thickened roots
Growth reduction
Mottled leaf
chlorosis
Leaf chlorosis,
thickened roots
Growth reduction
No injury to plant
Growth reduction
and visual symptoms
of Se phytotoxicity
Chlorosis
Chlorosis
Chlorosis
Chlorosis
References
Yopp et al.,
(p. 201)
Yopp et al . ,
(p. 201)
Yopp et al. ,
(p. 201)
Yopp et al.,
(p. 201)
Yopp et al . ,
(p. 201)
Yopp et al.,
(p. 201)
Yopp et al.,
(p. 201)
Yopp et al.,
(p. 201)
Yopp et al.,
(p. 201)
Yopp et al.,
(p. 199)
Yopp et al.,
(p. 199)
Rosenfeld and
Beath, 1964
(p. 118)
1974
1974
1974
1974
1974
1974
1974
1974
1974
1974
1974
a All values represent minimum phytotoxic concentrations.
weights are given in parenthesis.
b NR = Not reported.
c NA = Not applicable.
d Se applied in culture solution with 16 ppm sulfur.
e Se applied in culture solution with 32 ppm sulfur.
' Minimum phytotoxic concentration.
8 Se applied in culture solution with 96 ppm sulfur.
n Se applied in culture solution with 192 ppm sulfur.
Concentrations were converted to dry weight assuming a 202 soil moisture content. Wet
-------
TABLE 4-2. UPTAKE OF SELENIUM BY PLANTS
Co
Plant/Tissue
Corn/roots
Corn/stems
Corn/leaves
Corn/grain
Corn/roots
Corn/stems
Corn/leaves
Corn/grain
Wheat
Wheat
Wheat
Wheat
Alfalfa
Chemical Form
Applied
Selenite
Selenite
Selenite
Selenite
Se as aqueous
extract of A.
bisulcatus
Se as aqueous
extract of A.
bisulcatus
Se as aqueous
extract of A.
bisulcatus
Se as aqueous
extract of A.
bisulcatus
Na2SeC>4 ( + 16 ppm S)
Na2Se(>4 (+32 ppm S)
Na2Se(>4 (+96 ppm S)
Na2SeC>4 ( + 192 ppm S)
Selenite
Soil Range of Tissue
Soil Concentration (N)a Concentration Uptake'1
pl| (pg/g) (pg/g DW) Slope References
Nutrient solution 0.5-5.0 (4) NRC
Nutrient solution 0-5-5.0 (4) NR
Nutrient solution 0.5-5.0 (4) NR
Nutrient solution 0.5-5.0 (4) NR
Nutrient solution 0.5-5.0 (4) NR
Nutrient solution 0.5-5.0 (A) NR
Nutrient solution 0.5-5.0 (A) NR
Nutrient solution 0.5-5.0 (A) NR
NR 0-2 (3) 0
NR 0-2 (3) 0
NR 0-2 (3) 0
NR 0-2 (3) 0
NR 0-2 (3) 0
A1.6 Rosenfeld and Beath, 196A
(p. 110)
5A.7
42.9
31.8
348 Rosenfeld and Beath, 1964
(p. 110)
157
136
135
151. (107)4 Rosenfeld and Beath, 1964
82.5 (55)d (p. 118)
25 (17)d
24 (16)d
48.5 (32.3)d Rosenfeld and Beath, 1964
(p. 109)
a N = number of application rates.
b Slope = y/x: y = tissue concentration; x = soil concentration.
c NR = Not reported.
d Value in parenthesis represents the slope after conversion to Mg/g DW (kg/ha)"'.
-------
TABLE 4-3. TOXICITY OP SELENIUM TO DOMESTIC ANIMALS AND WILDLIFE
Feed Water
Chemical Concentration Concentration
Species (N)a Form Fed (fg/g) (mg/L)
Chicken (10) Se02 5 NRb
10 NR
Chicken, hen (20) Na2Se03 7 NR
Chicken, hen NaiSeOi 8 NR
4>
I
Daily
Intake
(mg/kg)
NR
NR
NR
NR
Duration
of Study
4-5 weeks
NR
16 weeks
2 weeks or
longer
Effects
Tendency for increased
mortality from S.
gallinarum infection.
Decreased gain and
increased mortality from
S. gallinarum infection.
None on egg production,
decreased egg weight
and hatchability.
Embryos incubated to 5
weeks showed no gross
References
Hill, 1979C
Ort and Latshaw, 1978C
Gruenwald, 1958C
logically there was path-
ologic regression of
previously well formed
parts; the nervous system,
limb buds, eyes exhibited
necrosis.
Rat (10)
Hamster (8)
Seleniferous 4.4
wheat
8.8
17.5
Na2Se03 6
9
NR
NR
NR
NK
NR
NR
NR
NR
NR
NR
100 days
NR
NR
4 weeks
NR
Slightly decreased gain Moxon, 1937C
Moderately decreased gain
Markedly decreased gain and
weight loss after 70 days.
None on gain; water Hadjimarkos, 1970C
consumption reduced 30Z
Decreased gain and water
consumption 45Z
-------
TABLE 4-3. (continued)
Peed
Chemical Concentration
Species (N)a Form Fed (Mg/g)
Dog (10) Na2Se03 20
Seleniferous NR
corn
Swine (2) Na2Se03 0.1
Se-methionine NR
Se-methionine NR
Na2Se03 10
Water Daily
Concentration Intake Duration
(mg/L) (rag/kg) of Study
NR
NR
NR
NR
NR
NR
NR Several weeks
NR NR
"NR 35-39 days
NR 35-38 days
NR 38 days
NR 56 days
Effects References
Decreased feed consumption Moxon, 1937C
and gain; dull'-eyed;
sluggish; wandered
aimlessly.
Decreased feed consumption
and gain; dull-eyed;
sluggish;- wandered
aimlessly.
No adverse effect Herigstad et al., 1973C
No adverse effect
No adverse effect
No adverse effect
i
»-j
tn
Swine (2)
Swine (2)
Swine (5)
20
Se-methionine
NR
Se-methionine
Seleniferous
corn
NR
5
10
NR
NR
NR
NR
NR
NR
NR 84 days Anorexia; emesis; weight
loss; depression; dyspnea
and death of one pig at
32 days; no effect on
second pig.
NR 63-84 days Decreased weight gain
in one pig.
NR 63 days Weight loss and death of
one pig at 3 days;
decreased weight gain and
toxic signs in second
pig.
NR 5-9 days Weight loss and death
NR NR No. adverse effect
NR NR Signs of toxicosis in 60Z
Herigstad et al., 1973C
Schoening, 1936C
-------
TABLE 4-3. (continued)
Chemical
Species (N)a Form Fed
Swine (4) Na2Se03
Swine females (10) Na2Se03
Swine (2) Na2Se03
Horse (1) Na2Se03
Chicken, hen (2) Na2Se03
Feed
Concentration
(pg/g)
7
10
Through
weaning of
2 litter
24
115
0.1
3
5
5
9
Water
Concentration
(mg/O
NR
NR
NR
NR
NR
NR
NR
NR
NR
Daily
Intake Duration
(rag/kg) of Study
NR 108 days
NR NR
NR 79 days
NR 5 weeks
NR 28 weeks
NR NR
NR NR
NR 16 weeks
NR NR
Effects
Decreased gain; hair loss;
cracked hooves; emacia-
tion (by 5 weeks); 1 death
at 10 weeks.
Decreased conception rate
increased services per
conception; more small,
weak, and dead pigs at
birth; fewer and lighter
pigs at weaning.
Anorexia; hair loss;
liver degeneration; death.
Emaciation; listlessness;
loose hair in mane and
tail; softening and
scaling of hoof wall;
hemorrhagic and cirrhotic
liver; death.
No adverse effects
No adverse effects
None on egg production,
egg weight, or fertility;
decreased hatchability.
No adverse effect
Decreased egg weight,
production^ and
hatchability.
References
Wahlstrom et al., 19S6C
Uahlstrom and Olson, 1959C
Miller and Schoening, 1938°
Miller and Williams, 1940C
Ore and Latshaw, 1978°
;
-------
TABLE 4-3. (continued)
Feed
Chemical Concentration
Species (N)a Form Fed (pg/g)
Chicken, pullet Selenious acid 2
(SO)
Water Daily
Concentration Intake Duration
(mg/L) (mg/kg) of Study Effects
NR NR 76 weeks None, except possibly
increased weight at
20 weeks.
References
Thapar et al., 1969C
Chicken
Chicken, hen Seleniferous corn, 2.5
barley, and wheat
Chicken, pullet Na2SeC>3
Chicken
6.5, 3.2S
a
Chicken, hen Seleniferous corn, 10
barley, and wheat
Chicken, pullet Seleniferous corn, IS
barley, and wheat
NR
NR
NR
NR
NR
NR
NR
NR NR Reduced body weight, egg
weight, production, hatch-
ability, and progency
growth.
NR Several weeks No adverse effects Hoxon, 1937C
NR NR None on hatchability;
wiry down on many hatched
chicks and increased
mortality.
NR NR Decceased feed consumption
and weight; deformed
embryos.
NR NR Decreased weight gain.
NR NR Embryonic deformities and Noxon, 1937C
hatchability declined to
zero.
NR 5 weeks Decreased feed consumption,
weight; no decrease in egg
production or fertility;
deformed embryos and
hatchability declined to
zero.
-------
TABLE 4-3. (continued)
I
t->
CO
Species (N)a
Chicken (60)
Honkey (11)
cynomolgus
(macaca fascicu-
laris)
Rats
Horses
Rats
Cattle, sheep
Cattle, sheep,
horses
Pig
Feed Water Daily
Chemical Concentration Concentration Intake
Form Fed (Mg/g) (mg/L) (mg/kg)
Se02 2.5
5
10
20
40
Na2Se(>3 10
Se 10 (in 10Z
protein diet)
Se 10 (in 20Z
protein diet)
Se salts 1
SQ salts 44
Se 4-6
Se 5
Primary Se- 100-10,000
indicator plants
Forage 20-50
Se 12-18
NR
NR
NH
NR
NR
NR
NR
NR
0.5
2.0
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
0.5
1.0
NR
NR
NR
NR
NAd
Duration
of Study
2 weeks
NR
NR
NR
NR
40 days
NR
NR
NR
NR
60-100 days
NR
NR
NR
Single Dose
Effects
No adverse effect
No adverse effect
Cain 72Z of controls
Cain 30Z of controls
Cain 2Z of controls
Tongue erosions; crusty,
hemorrhagic tail derma-
tosis; loss of nails
(onychoptosis); anorexia;
lassitude; leukopenia.
Highly toxic
Tolerated
Chronic poisoning
Chronic poisoning
Lethal
Subacute selenosis
Se poisoning syndrome
Subacute selenosis
"alkali disease"
Minimum per acute
lethal dose
References
Hill, 1974C
Loew et al . ,
Euan, 1978 (p
Harr and Muth
(p. 176)
Harr and Muth
(p. 176)
Harr, 1978 (p
Harr and Nuth
(p. 177)
Harr and Muth
(p. 178)
Harr, 1978
1975C
. 449)
, 1972
, 1972
. 408)
, 1972
, 1972
a N = Number of animals/treatment group.
0 NR = Not reported.
c Obtained from NAS (1980), Table 29, pp. 402 to 415.
d NA = Not applicable.
-------
TABLE 4-4. UPTAKE OF SELENIUM BY DOMESTIC ANIMALS AND WILDLIFE
Chemical
Species Form Fed
Rats Se
Mice Selenite
Selenate
Guinea pigs Se in
Swiss chard
Pigs Sodium selenite
Pigs Natural diets
Rang<* (N)a
of Feed Tissue
Concentration
(Mg/g DW)
0-0.25 (4)
0.1-3 (2)
0.1-3 (2)
0.05-0.08 (3)
0.04-0.44 (2)e
0.027-0.493 (2)
Tissue
Analyzed
Liver
Heart
Liver
Kidney
Spleen
Heart
Liver
Kidney
Spleen
Liver
Muscle
Liver
Muscle
Kidney
Muscle
Control Tissue
Concentration
(Mg/g UW)
0.40
0.24
0.54
1.19
0.8
0.19
0.22
0.56
0.19
1.12C
0.38C
NRf
NR
NR
NR
Uptake6
Slope References
2.75 . Uarr et al., 1978 (p. 430-431)
0.33 Schroeder and Mitchner, 1972 (p. 69)
0.69
0.24
1.31
0.09 Schroeder and Mitchner, 1972 (p. 70)
0.18
0.11
0.13
10. ld Purr et al., 1976 (pp. 87 to 88)
2.07d
0.575 HAS, 1980 (p. 399)
0.9
0.075
1.058 HAS, 1980 (p. 399)
a N = Number of feed rates.
b Slope = y/x: y = tissue concentration; x = plant concentration.
c Mg/g tissue DW.
d y and x both in DW.
e 0.04. represents an Se deficient diet, 0.44 represents Se sufficient diet.
f NR = Not reported.
8 Only the ranges of dietary and tissue concentrations were reported. Since diet and tissue levels were highly correlated (r = 0.95), it was
assumed that the highest tissue concentration occurred with the highest diet, and the lowest with the lowest, so that a slope could be computed
from these ranges.
-------
SECTION 5
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Selenium Poisoning in Growing and Fattening Pigs. S. Dak. Agric.
Exp. Etn. Bull. No. 456. ' South Dakota State College, Agricultural
Experiment Station, Brookings, SD. (As cited in NAS, 1980.)
Wahlstrom, R. C., and 0. E. Olson. 1959. The Effect of Selenium on
Reproduction in Swine. J. Ani. Sci. 18:141. (As cited in NAS,
1980.)
5-5
-------
Wolnik, K., F. L. Fricke; S. G. Caper et al. 1983. Element in Major
Raw Agricultural Crops in the USDA. 2. Other Elements in Lettuce,
Potatoes, Soybeans, Sweet Corn, and Wheat. J. Agr. Food. Chem.
31:1244.
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. Illinois
Institute for Environmental Quality. IIEQ Doc. No. 74-33.
5-6
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APPENDIX
PRELIMINARY HAZARD INDEX CALCULATIONS FOR SELENIUM
IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTTON-AND-MARKETING
A. Effect on Soil Concentration of Selenium
1. Index of Soil Concentration Increment (Index 1)
a. Formula
_ , . (SC x AR) + (BS x MS)
IndeX 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
(1.111 ug/g DW x 5 mt/ha) f (0.21 Ug/g DW x 2000 mt/ha)
0.21 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 = -^g
where:
1]^ = 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 - 1XBS x UB) + BB
Index 3 = =^
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
(Ug/g tissue DW [ug/g soil DW]'1)
BB = Background concentration in soil biota
(Ug/g DW)
TR = Feed concentration toxic to predator (ug/g
DW)
b. Sample calculation - Values were not calculated due
to lack of data.
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 (ug/g DW)
TP = Soil concentration toxic to plants (ug/g
DW)
Sample calculation
. 'Q, _ 1.0107 x 0.21 ug/g DW
°'1895 ~ 1.12 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:
II = Index 1 = Index of soil concentration
increment (unitless)
BS = Background concentration of pollutant in
soil (ug/g DW)
CO = 2 kg/ha (ug/g)"1 = 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
_ (1.0107-1) x 0.21 ug/g DW 2 kg/ha
0.20 ug/g DW x ug/g soil
7.8 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
s 429 Ug/g DW
0.20 ug/g DW
A-3
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C. Effect on Herbivorous Animals
1. Index of Animal Toxicity Resulting from Plant Consumption
(Index 7)
a. Formula
I5 x BP
Index 7 =
where:
15 = 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 DW)
b. Sample calculation
n m^A - 1.175 x 0.20 Ug/g DW
°'°336 - 7 ug/g DW
2. Index of Animal Toxicity Resulting from Sludge Ingestion
(Index 8)
a. Formula
BS x GS
TA
SC x GS
If AR = 0, Ig =
If AR ^ 0, 13 =
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 DW)
Sample calculation
If AR = 0, 0.0015 =
If AR t 0, 0.0079 - -
A-4
-------
B. Effect on Humans
1. Index of Human Toxicity Resulting from Plant Consumption
(Index 9)
a. Formula
[(Is - 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 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)
n ..,. _ [(1.175 - 1) x Q.2Q ug/g DW x 74.5 g/day] + 46.3 Ug/day
U A U / D ~ /cc /i
455 ug/day
2. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Feeding on Plants
(Index 10)
a. Formula
[(Is - 1) BP x UA x DA] + DI
Index 10 - 5 _
where:
15 = Index 5 = Index of plant concentration
increment caused by uptake (unitless)
BP = Background concentration in plant tissue
(jlg/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)
0.1165 =
(1.175-1) x 0.20 ue/g DW x 3.75 Ug/g tissue[ug/g feed]"1 x 51.1 g/day] + 46.3 ug/dav
455 pg/day
3. Index of Human Toxicity Resulting from Consumption of
Animal Products Derived from Animals Ingesting Soil
(Index 11)
a. Formula
If AR - 0, Index 11 = (BS * GS * U*p* DA) * DI
If AR * 0, Index 11 =
-------
where:
l± = Index 1 = Index of soil concentration
increment (unitless)
SC = Sludge concentration . of pollutant
(yg/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)
- (1.0107 x 0.21 ug/g DW x 5 g soil/day) + 46.3 Ug/day
~ 455 Ug/day
.Pure sludge:
_ (1.111 Ug/g DW x 5 g soil/day) * 46.3 Ug/day
U i .1 HU ~" /re / j
455 Ug/day
5. Index of Aggregate Human Toxicity (Index 13)
a. Formula
Index 13 = I9 + I10 + In + Ii2 ~ fff
where:
Ig' = 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 11 = Index of human toxicity
resulting from consumption of animal
products derived from animals ingesting
soil (unitless)
1^2 = Index 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
(Ug/day)
A-7
-------
b. Sample calculation (toddler)
0.141 = (0.1075 « 0.1165 + 0.1182 + 0.1041) - (3 x 46.3 pg/day }
455 ug/day
II. LANDPILLING
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,
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, Co, 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(A]_) erfc(A2) + exp(Bj_) erfc(B2)] = P(x,t)
Requires evaluations of four dimensionless input values and
subsequent evaluation of the result. Exp(A^) 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:
A. = X_ [V* - (V*2 + 40* x u*
Al 20*
_ Y - t (V*2 + 40* x U*)?
[V* + (V*2 + 4D* x
20*
Y + t (V*2 + 40-=-- x U*)
82 (4D* x t)?
A-8
-------
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 =
20%
t = Time (years)
X = h = Depth to groundwater (m)
D* = a x V* (m2/year)
a = Dispersivity coefficient (m)
V* = 2 (m/year)
V 0 x R
Q = Leachate generation rate (m/year)
0 = Volumetric water content (unitless)
R = 1 + dry x KJ = Retardation factor (unitless)
0
pdry = Dry bulk density (g/mL)
K^ = Soil sorption coefficient (mL/g)
(years)-l
i
U = Degradation rate (day"1)
and where for the saturated zone:
Co = Initial concentration of pollutant in aquifer as
determined by Equation 2 (ug/L)
t = Time (years)
X = A2, = Distance from well to landfill (m)
D* = a x V* (m^/year)
a = Dispersivity coefficient (m)
V* = K x i (m/year)
-------
where:
Co = Initial concentration of pollutant in the saturated
zone as determined by Equation 1 (ug/L)
Cu = Maximum pulse concentration from the unsaturated
zone (ug/D
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)
0 = Aquifer porosity (unitless)
B = Thickness of saturated zone (m) where:
B> - 9 *. W « - and B > 2
K x i x 365
Equation 3. Pulse Assessment
C(x?t) = P(x,t) for 0 < t < t0
C - - o
Co
= P(x,t) - P(X,t - C0) for t > t
where:
to (for unsaturated zone) = LT = Landfill leaching time
(years )
to (for saturated zone) = Pulse duration at the water
table (x = n) as determined by the following equation:
t0 = ( J °° C dt] t Cu
P(X»t) = -~ as determined by Equation 1
co
E. Equation 4. Index of Groundwater Concentration Increment
Resulting from Landfilled Sludge (Index 1)
1. Formula
r , , Cmax + BC
Index 1 =
where:
Cmax = Maximum concentration of pollutant at well =
Maximum of C(Afc,t) calculated in Equation 1
(Ug/U
BC = Background concentration of pollutant in
groundwater (pg/L)
A-10
-------
2. Sample Calculation
,
1-
- 0-030 Ug/L + 8 ug/L
' 8 ug/L
P. Equation 5. Index of Human Toxicity Resulting from
Groundwater Contamination (Index 2)
1. Formula
[(I 1 - 1) BC x AC] + DI
index 2= i - -
where :
Ij_ = 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
_ ... _ [(1.004 - 1) x 8 ug/L x 2 L/davl + 110.7 Ug/day
U ^'t j ~~ iff it
455 Ug/day
III. INCINERATION
A. Index of Air Concentration Increment Resulting from
Incinerator Emissions (Index 1)
1. Formula
T , . (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)
OS = 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 (ug/m^)
BA = Background concentration of pollutant in urban
air (yg/m-*)
A-ll
-------
2. Sample Calculation
1.031 = [(2.78 x 10~7 hr/sec x g/mg x 2660 kg/hr DW x
1.111 mg/kg DW x 0.01 x 3.4 yg/m3) +
0.0009 yg/m3] * 0.0009 ug/m3
B. Index of Human Toxicity Resulting from Inhalation of
Incinerator Emissions (Index 2)
1. Formula
[(Ii - 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/m3)
EC = Exposure criterion (yg/m3)
2. Sample Calculation
0 00027 = Kl.031 - 1) x 0.0009 Ug/m31 + 0.0009 Ug/m3
3.5 Ug/m3
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 (pg/g DU)
Unsaturated zone
Soil type and characteristics
Dry bulk density, P,jry (g/mL)
Volumetric water content, 6 (unitless)
Soil sorption coefficient, Kj (mL/g)
Site parameters
Leachate generation rate, Q (in/year)
Depth to groundwater, h (m)
Dispersivity 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, AH (m)
Dispersivity coefficient, a (m)
1
1.111
1.53
0.195
14.9
0.8
5
0.5
0.44
0.86
0.001
100
10
2
4.848
1.53
0.195
14.9
0.8
5
0.5
0.44
0.86
0.001
100
10
3
1.111
1.925
0.133
5.91
0.8
5
0.5
0.44
0.86
0.001
100
10
4 5
1.111 . 1.111
NAb 1.53
NA 0.195
NA 14.9
1.6 0.8
0 5
NA 0.5
0.44 0.389
0.86 4.04
0.001 0.001
100 100
10 10
6
1.111
1.53
0.195
14.9
0.8
5
0.5
0.44
0.86
0.02
50
5
7 8
4.848 Na
NA N
NA N
NA N
1.6 N
0 N
NA N
0.389 N
4.04 N
0.02 N
50 N
5 N
-------
TABLE A-l. (continued)
I
I-1
-p>
Condition of Analysis
Results
Unaaturated zone assessment (Equations 1 and 3)
Initial leachate concentration, C0 (pg/L)
Peak concentration, Cu (iig/L)
Pulse duration, to (years)
Linkage assessment (Equation 2)
Aquifer thickness, B (m)
Initial concentration in saturated zone, Co
(Mg/L)
1
278
10. B
129
126
10.8
2
1210
47. 0
129
126
47.0
3
278
21.5
64.6
126
21.5
4
278
278
5.00
253
278
5
278
10.8
129
23.8
10.8
6
278
10.8
129
6.32
10.8
7
1212
1212
5.00
2.38
1210
8
N
N
N
N
N
Saturated zone assessment (Equations 1 and 3)
Maximum well concentration, Cmax ((jg/L)
Index of groundwater concentration increment
resulting from landfilled sludge,
Index 1 (unicleas) (Equation 4)
Index of human toxicity resulting from
groundwater contamination, Index 2
(unitless) (Equation 5)
0.030
1.00
0.243
0.132
1.02
0.244
0.030
1.00
0.243
0.030 0.161 1.20 28.1 N
1.00 1.02 1.15 4.51 0
0.243 0.244 0.249 0.367 0.243
*N = Null condition, where no landfill exists; no value is used.
"NA = Not applicable for this condition.
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