United States
Environmental Protection
Agency
Office of Water
Regulations and Standards
Washington, DC 20460
Water
June, 1985
Environmental Profiles
and Hazard Indices
for Constituents
of Municipal Sludge:
2,4-Dichlorophenoxyacetic
Acid
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I
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, Landf illing,
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.
n
Constitution Ave NW
Washington DC 20004
202-566-0556
Repository Material
Permanent Collection
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TABLE OP CONTENTS
Page
PREFACE i
1. INTRODUCTION 1-1
2. PRELIMINARY CONCLUSIONS FOR 2,4-DICHLOROPHENOXYACETIC ACID
IN MUNICIPAL SEWAGE SLUDGE 2-1
Landspreading and Distribution-and-Marketing 2-1
Landfilling 2-1
Incineration 2-1
Ocean Disposal 2-1
3. PRELIMINARY HAZARD INDICES FOR 2,4-DICHLOROPHENOXYACETIC
ACID IN MUNICIPAL SEWAGE SLUDGE 3-1
Landspreading and Distribution-and-Marketing 3-1
Landf illing . 3-1
Index of groundwater concentration resulting
from landfilled sludge (Index 1) 3-1
Index of human toxicity resulting from
groundwater contamination (Index 2) 3-8
Incineration 3-9
Ocean Disposal 3-9
4. PRELIMINARY DATA PROFILE FOR 2,4-DICHLOROPHENOXYACETIC
ACID IN MUNICIPAL SEWAGE SLUDGE 4-1
Occurrence 4-1
Sludge 4-1
Soil - Unpolluted 4-1
Water - Unpolluted 4-2
Air 4-2
Food 4-3
Human Effects 4-3
Ingestion 4-3
Inhalation 4-4
11
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TABLE OP CONTENTS
(Continued)
Page
Plane Effects 4-5
Phytotoxicity 4-5
Uptake 4-5
Domestic Animal and Wildlife Effects 4-5
Toxicity 4-5
Uptake 4-5
Aquatic Life Effects 4-5
Soil Biota Effects 4-5
Toxicity 4-5
Uptake 4-6
Physicochemical Data for Estimating Fate and Transport 4-6
5. REFERENCES 5-1
APPENDIX. PRELIMINARY HAZARD INDEX CALCULATIONS FOR
2,4-DICHLOROPHENOXYACETIC ACID 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. 2,4-Dichlorophenoxyacetic acid (2,4-D) was initially
identified as being of potential concern when sludge is placed in a
landfill.* This profile is a compilation of information that may be
useful in determining whether 2,4-D poses an actual hazard to human
health or the environment when sludge is disposed of by this method.
The focus of this document is the calculation of "preliminary
hazard indices" for selected potential exposure pathways, as shown in
Section 3. Each index illustrates the hazard that could result from
movement of a pollutant by a given pathway to cause a given effect
(e.g., sludge •* groundwater •* human toxicity). The values and assump-
tions employed in these calculations tend to represent a reasonable
"worst case"; analysis of error or uncertainty has been conducted to a
limited degree. The resulting value in most cases is indexed to unity;
i.e., values >1 may indicate a potential hazard, depending upon the
assumptions of the calculation.
The data used for index calculation have been selected or estimated
based on information presented in the "preliminary data profile",
Section 4. Information in the profile is based on a compilation of the
recent literature. An attempt has been made to fill out the profile
outline to the greatest extent possible. However, since this is a pre-
liminary analysis, the literature has not been exhaustively perused.
The "preliminary conclusions" drawn from each index in Section 3
are summarized in Section 2. The preliminary hazard indices will be
used as a screening tool to determine*which pollutants and pathways may
pose a hazard. Where a potential hazard is indicated by interpretation
of these indices, further analysis will include a more detailed exami-
nation of potential risks as well as an examination of site-specific
factors. These more rigorous evaluations may change the preliminary
conclusions presented in Section 2, which are based on a reasonable
"worst case" analysis.
The preliminary hazard indices for selected exposure routes
pertinent to landfilling practices are included in this profile. The
calculation formulae for these indices are shown in the Appendix. The
indices are rounded to two significant figures.
* Listings were determined by a series of expert workshops convened
during March-May, 1984 by the Office of Water Regulations and
Standards (OWRS) to discuss landspreading, landfilling, incineration,
and ocean disposal, respectively, of municipal sewage sludge.
1-1
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SECTION 2
PRELIMINARY CONCLUSIONS FOR 2,4-DICHLOROPHENOXYACETIC ACID
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-MARKETINC
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
II. LANDPILLING
Landfilled sludge will produce a maximum groundwater concentration
of 2,4-D at the well which varies over three orders of magnitude
depending upon the soil type, site parameters, and chemical-
specific parameters (see Index 1). The 2,4-D groundwater contami-
nation produced by landfilled sludge is not expected to pose a
human health risk under any of the site conditions analyzed (see
Index 2).
III. INCINERATION
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S.. EPA reserves the right
to conduct such an assessment for this option in the future.
2-1
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SECTION 3
PRELIMINARY HAZARD INDICES FOR 2,4-DICHLOROPHENOXYACETIC ACID
IN MUNICIPAL SEWAGE SLUDGE
I. LAMDSPREADING AND DISTRIBUTION-AND-MARKETING
Based on the recommendations of the experts at the OURS 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 an assessment for this option in the future.
II. LANDFILLING
A. Index of Groundwater Concentration Resulting from Landfilled
Sludge (Index 1)
1. Explanation - Calculates groundwater contamination which
could occur in a potable aquifer in the landfill vicin-
ity. Uses U.S. EPA's Exposure Assessment Group (EAG)
model, "Rapid Assessment of Potential Groundwater Contam-
ination Under Emergency Response Conditions" (U.S. EPA,
1983). 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
3-1
-------
Che vertical direction throughout the unsaturated zone,
and only in the horizontal (longitudinal) plane in the
saturated zone; pollutant movement is considered only in
direction of groundwater flow for the saturated zone; all
pollutants exist in concentrations that do not signifi-
cantly affect water movement; for organic chemicals, the
background concentration in the soil profile or aquifer
prior to release from the source is assumed to be zero;
the pollutant source is a pulse input; no dilution of the
plume occurs by recharge from outside the source area;
the leachate is undiluted by aquifer flow within the
saturated zone; concentration in the saturated zone is
attenuated only by dispersion.
3. Data Used and Rationale
a. Unsaturated zone
i. Soil type and characteristics
(a) Soil type
Typical Sandy loam
Worst Sandy
These two soil types were used by Gerritse et
al. (1982) to measure partitioning of elements
between soil and a sewage sludge solution
phase. They are used here since these parti-
tioning measurements (i.e., K^ values) are con-
sidered Che 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
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),
1984a).
(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 the media and the water flux
3-2
-------
estimated by infiltration or net recharge. The
volumetric water content is used in calculating
the water movement through the unsaturated zone
(pore water velocity) and the retardation
coefficient. Values obtained from CDM, 1984a.
(d) Fraction of organic carbon (foc)
Typical 0.005 (unitless)
Worst 0.0001 (unitless)
Organic content of soils is described in terms
of percent organic carbon, which is required in
the estimation of partition coefficient, Kj.
Values, obtained from R. Griffin (1984) are
representative values for subsurface soils.
ii. Site parameters
(a) Landfill leaching time (LT) = 5 years
Sikora et al. (1982) monitored several sludge
entrenchment sites throughout the United States
and estimated time of landfill leaching to be 4
or 5 years. Other types of landfills may leach
for longer periods of time; however, the use of
a value for entrenchment sites is conservative
because it results in a higher leachate
generation rate.
(b) Leachate generation rate (Q)
Typical 0.8 m/year
Worst 1.6 m/year
It is conservatively assumed that sludge
leachate enters the unsaturated zone undiluted
by precipitation or other recharge, that the
total volume of liquid in the sludge leaches
out of the landfill, and that leaching is com-
plete in 5 years. Landfilled sludge is assumed
to be 20 percent solids' by volume, and depth of
sludge in the landfill is 5 m in the typical
case and 10 m in the worst case. Thus, the
initial depth of liquid is 4 and 8 m, and
average yearly leachate generation is 0.8 and
1.6 m, respectively.
(c) Depth to groundwater (h)
Typical 5 m
Worst 0 m
3-3
-------
Eight landfills were monitored throughout the
United States and depths to groundwater below
them were listed. A typical depth to ground-
water of 5 m was observed (U.S. EPA, 1977).
For the worst case, a value of 0 m is used to
represent the situation where the bottom of the
landfill is occasionally or regularly below the
water table. The depth to groundwater must be
estimated in order to evaluate the likelihood
that pollutants moving through the unsaturated
soil will reach the groundwater.
(d) Dispersivity coefficient (a)
Typical 0.5 m
Worst Not applicable
The dispersion process is exceedingly complex
and difficult to quantify, especially for the
unsaturated zone. It is sometimes ignored in
the unsaturated zone, with the reasoning that
pore water velocities are usually large enough
so that pollutant transport by convection,
i.e., water movement, is paramount. As a rule
of thumb, dispersivity may be set equal to
10 percent of the distance measurement of the
analysis (Gelhar and Axness, 1981). Thus,
based on depth to groundwater listed above, the
value for the typical case is 0.5 and that for
the worst case does not apply since leachate
moves directly to the unsaturated zone.
iii. Chemical-specific parameters
(a) Sludge concentration of pollutant (SC)
Typical 4.64 mg/kg DW
Worst 7.16 mg/kg DW
Of over 200 publicly-owned treatment works
(POTWs) surveyed in the United States, analyses
for 2,4-D were conducted only at two Phoenix,
Arizona plants (COM, 1984b). The mean and max-
imum concentrations of 2,4-D in the sludge at
these two POTWs is used for the typical and
worst concentration, respectively. Although
these concentrations may be biased due to
unique local conditions, they were used because
they are the only specific values available.
(See Section 4, p. 4-1.)
3-4
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(b) Soil half-life of pollutant (tp = 135 days
The value selected represents the longest
(worst-case) half-life for 2,4-D reported in a
study which compared degradation rates under
aerobic and anaerobic conditions (Liu et al.,
1981). (See Section 4, p. 4-6.)
(c) Degradation rate (p) = 5.13 x 10"3 day'1
The unsaturated zone can serve as an effective
medium for reducing pollutant concentration
through a variety of chemical and biological
decay mechanisms which transform or attenuate
the pollutant. While these decay processes are
usually complex, they are approximated here by
a first-order rate constant. The degradation
rate is calculated using the following formula:
(d) Organic carbon partition coefficient (Koc) -
20 mL/g
The organic carbon partition coefficient is
multiplied by the percent organic carbon
concent of soil (foc) to derive a partition
coefficient (K
-------
(b) Aquifer porosity (0)
Typical 0.44 (unitless)
Worst 0.389 (unitless)
Porosity is that portion of the total volume of
soil that is made up of voids (air) and water.
Values corresponding to the above soil types
are from Pettyjohn et al. (1982) as presented
in U.S. EPA (1983).
(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 (1983).
(d) Fraction of organic carbon (foc) =
0.0 (unitless)
Organic carbon content, and therefore adsorp-
tion, is assumed to be 0 in the saturated zone.
ii. Site parameters
(a) Average hydraulic gradient between landfill and
well (i)
Typical 0.001 (unitless)
Worst 0.02 (unitless)
The hydraulic gradient is the slope of the
water table in an unconfined aquifer, or the
piezometric surface for a confined aquifer.
The hydraulic gradient must be known to
determine the magnitude and direction of
groundwater flow. As gradient increases, dis-
persion is reduced. Estimates of typical and
high gradient values were provided by Donigian
(1985).
.3-6
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(b) Distance from well to landfill (A&)
Typical 100 m
Worst 50 m
This distance is the distance between a
landfill and any functioning public or private
water supply or livestock water supply.
(c) Dispersivity coefficient (a)
Typical 10 m
Worst 5 m
These values are 10 percent of the distance
from well to landfill (AH), which is 100 and
SO 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 ic 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 (U) = 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 (u) = 0 day'1
Degradation is assumed not to occur in the
saturated zone.
(b) Background concentration of pollutant in
groundwater (BC) = 0 Ug/L
It is assumed that no pollutant exists in the
soil profile or aquifer prior to release from
the source.
4. Index Values - See Table 3-1.
3-7
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S. Value Interpretation - Value equals the maximum expected
groundwater concentration of pollutant, in Ug/L, at the
well.
6. Preliminary Conclusion - Landfilled sludge will produce a
maximum groundwater concentration of 2,4-D at the well
which varies over three orders of magnitude dependi-ng
upon the soil type, site parameters, and chemical-
specific parameters.
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 resulting from
landfilled sludge (Index 1)
See Section 3, p. 3-10.
b. 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.
c. Average daily human dietary intake of pollutant (DI)
= 2.81 Mg/day
Although no 2,4-D residues were reported in market
basket surveys from FY75 to FY78 (Food and Drug
Administration (FDA), 1979), a worst-case average
daily human dietary intake was calculated with prior
food concentration data (Johnson and Manske, 1976;
Manske and Johnson, 1975) and average daily consump-
tion data for adults (FDA, 1980). The concentration
of 2,4-D reported for potatoes and leafy vegetables
was multiplied by the respective average daily adult
consumption (159 g/day potatoes and 58 g/day leafy
vegetables; FDA, 1980) and summed to obtain the
total average daily human dietary intake of 2,4-D
reported above. (See Section 4, p. 4-3).
3-8
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d. Acceptable daily intake of pollutant (ADI) =
8750 Ug/day
Using an uncertainty factor of 100, the U.S. EPA
(1982) calculated an ADI of 0.125 mg/kg/day (see
Section 4, p. 4-4). Assuming the average adult
weights 70 kg (U.S. EPA, 1982), the value given was
calculated by multiplying 0.125 mg/kg/day by 70 kg
and converting mg to Ug (1000 Ug/mg).
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
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 - The 2,4-D groundwater contamina-
tion produced by landfilled sludge is not expected to
pose a human health risk under any of the site conditions
analyzed.
III. INCINERATION
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
3-9
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TABLE 3-1. INDEX OP CROUNDWATER CONCENTRATION RESULTING FROM LANDFILLED SLUDGE (INDEX 1) AND
INDEX OF HUMAN TOXICITY RESULTING FROM GROUNDUATER CONTAMINATION (INDEX 2)
I
»->
o
Site Characteristics
Sludge concentration
Unsaturated Zone
Soil type and charac-
teristics^
Site parameters6
Saturated Zone
Soil type and charac-
teristics^
Site parameters^
Index 1 Value (ug/L)
Index 2 Value
1
T
T
T
T
T
0.0186
3.3x10-4
2
U
T
T
T
T
0.0287
3.3,10-4
3
T
W
T
T
T
0.0321
3.3x10-4
Condition of
4
T
NA
U
T
T
0.1261
3.5x10-4
Analysisa»D»c
5
T
T
T
W
T
0.0987
3.4x10-4
6
T
T
T
T
U
0.7435
4.9x10-4
7
W
NA
U
W
U
41.43
9.8xlO-3
8
N
N
N
N
N
0
3.2x10-4
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 (P(jry)» volumetric water content (6), and fraction of organic carbon (foc).
eLeachate generation rate (Q), depth to groundwater (h), and dispersivity coefficient (a).
'Aquifer porosity (0) and hydraulic conductivity of the aquifer (K).
^Hydraulic gradient (i), distance from well to landfill (AS,), and dispersivity coefficient (a).
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SECTION 4
PRELIMINARY DATA PROFILE FOR 2,4-DICHLOROPHENOXYACETIC ACID
IN MUNICIPAL SEWAGE SLUDGE
I. OCCURRENCE
2,4-D was introduced as a plant growth-regulator MAS, 1977
in 1942. It is registered in the United States (p. 493)
as an herbicide for control of broadleaf plants
and as a plant growth-regulator. Domestic use is
estimated at 40 to 50 million Ibs/yr, approxi-
mately 84% of which is used agriculturally and
about 16Z non-agriculturally (mainly for forest
brush control).
A. Sludge
1. Frequency of Detection
Data not immediately available.
2. Concentration
Concentrations in sludges from five Jones and Lee,
sludge sources in Chicago were <1000 1977 (p. 52)
Mg/L.
In 4 composite samples from two Phoenix, CDM, 1984b
Arizona treatment plants, 2,4-D ranged (pp. 43-56)
from 2.12 to 7.16 mg/kg DW with a mean
of 4.64 mg/kg DW.
B. Soil - Unpolluted
1. Frequency of Detection
Out of 188 samples from soils where U.S. EPA,
2,4-D had been applied, 1.6Z contained 1981 (p. 7-6)
2,4-D residues (1969).
No 2,4-D detected in soil samples U.S. EPA,
from the corn belt in 1970. 1981 (p. 7-7)
2,4-D detected in 20% of soil samples U.S. EPA,
from wheat fields in 1969. 1981 (p. 7-7)
2. Concentration
In 1.6% of 188 soil samples from 2,4-D U.S. EPA,
application sites, 2,4-D had a mean 1981 (p. 7-7)
concentration of <0.01 ug/g (1969).
4-1
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In 20% of soil samples from wheat fields U.S. EPA, 1981
in 1969, 2,4-D was detected with a (p. 7-7)
maximum value of 0.2 yg/g DU.
C. Hater - Unpolluted
1. Frequency of Detection
No detectable 2,4-D found in monthly U.S. EPA, 1981
water-suspended samples from 11 rivers (p. 7-5)
in the western United States in 1965-66.
2,4-D detected in 14 out of 20 stations U.S. EPA, 1981
on 19 rivers in 1967-68. (p. 7-5)
No measurable levels of 2,4-D detected U.S. EPA, 1981
in Texas surface waters in 1970. (p. 7-6)
2. Concentration
a. Freshwater
In a two-year study of 19 western U.S. EPA, 1981
U.S. rivers, the highest 2,4-D con- (p. 7-5)
centration found was 0.35 Ug/L in
the James River at Huron, SD, in 1968.
The highest concentration of 2,4-D U.S. EPA, 1981
detected in a three-year study (1968- (p. 7-6)
1971) of 19 western U.S. streams was
0.97 ug/L.
b. Seawater
Data not immediately available.
c. Drinking Water
Data not immediately available.
D. Air
1. Frequency of Detection
In a one-year monitoring study of air U.S. EPA, 1981
in 16 U.S. cities, three samples (p. 7-4)
contained detectable 2,4-D levels.
The isopropyl ester of 2,4-D was found U.S. EPA, 1981
in 20 out of 22 samples of air in north- (p. 7-1)
eastern Oregon in 1962. In eastern
Washington, 2,4-D esters were present
in 60 to 70% of the samples.
4-2
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2. Concentration
Urban
In a one-year monitoring study of
air in 16 U.S. cities, three samples
contained 2,4-D as follows:
Jordan, NY
Rome, NY
Salt Lake City, UT
0.00115 Mg/m3
0.00154 pg/m3
0.004 yg/m3
b. Rural
Out of 434 samples from Oregon and
Washington in 1962 to 1964, the
concentration range for most 2,4-D
esters was from trace levels to 5.12
yg/m3.
B. Pood
1. Total Average Intake
In market basket surveys from FY75 co
FY78, no 2,4-D residues were reported.
Total diet samples detailing residues
in infant and toddler food and tap water
(1974-75) did not contain any detectable
2,4-D residues.
2. Concentration
2,4-D occurred in 1 out of 30 composite
potato samples in 1972-73 at a level
of 0.014 Mg/g.
2,4-D occurred in 1 out of 35 composite
leafy vegetable samples in 1971-72
at a level of 0.01 Ug/g.
II. HUMAN EFFECTS
A. Ingestion
1. Carcinogenicity
a. Qualitative Assessment
No conclusive evidence of
2,4-D carcinogenicity exists
when administered orally to
animals.
U.S. EPA, 1981
(p. 7-5)
U.S. EPA, 1981
(p. 7-2)
FDA, 1979
U.S. EPA, 1981
(p. 7-10)
Johnson and
Manske, 1976
Manske and
Johnson, 1975
(p. 100)
NAS, 1977
U.S. EPA, 1982
4-3
-------
b. Potency
Not derived.
c. Effects
No carcinogenic effects demonstrated.
2. Chronic Toxicity
a. ADI
0.3 mg/kg/day
0.0125 mg/kg/day - safety factor of
1000 used.
0.125 mg/kg/day - safety factor of
100 used (or 8.75 mg/man/day)
b. Effects
Fibrillary twitching, muscular
paralysis, hemoglobinuria,
myoglobinuria, general hyporeflexia.
3. Absorption Factor
75 to 90 percent absorption of ingested
2,4-D.
4. Existing Regulations
Quality criteria for a domestic water
supply set for 2,4-D at 0.1 mg/L
B. Inhalation
1. Carcinogenicity
Data not immediately available.
2. Chronic Tozicity
Data not assessed since no evaluation of
incineration was performed.
3. Absorption Factor
Data not immediately available.
FAO/WHO cited in
NAS, 1977
U.S. EPA, 1982
NAS, 1977
Kohli et al.,
1974, cited in
U.S. EPA, 1980
U.S. EPA, 1976
4-4
-------
4. Existing Regulations
10 mg/m3 Time weighted average
20 mg/n)3 Short-term exposure limit
III. PLANT EFFECTS
A. Phytotoxicity
See Table 4-1.
When combined with captan or dichlone,
2,4-D exhibited synergistic phytotoxicity
on cucumbers but not on oats.
Applications of 2,4-D resulted
in poor germination and malformed foot tips
in cotton plants and reduced germination of
poinsetta.
B. Uptake
Data not immediately available.
IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS
A. Toxicity
See Table 4-2.
B. Uptake
Data not immediately available.
V. AQUATIC LIFE EFFECTS
Data not immediately available.
VI. SOIL BIOTA EFFECTS
A. Tozicity
See Table 4-3.
Gram positive and aerobic bacteria were
inhibited at lower concentrations than gram
negative and anaerobic bacteria.
Very high levels of 2,4-D cause inhibition
of nitrification and ammonification.
ACGIH, 1983
Nash and Harris,
1973 (p. 495)
NAS, 1968 (p. 6)
Newman and
Downing, 1958
(p. 352)
Newman and
Downing, 1958
(p. 352)
4-5
-------
B. Uptake
Data not immediately available.
VII. PHYSICOCHEMICAL DATA FOR ESTIMATING FATE AND TRANSPORT
Persistence of 2,4-D in soils has been reported Liu et al., 1981
to be between 4 weeks and 3 years. (p. 788)
Under aerobic conditions, half-lives of 2,4-D Liu et al., 1981
were 1.8 to 3.1 days. Under anaerobic conditions, (p. 792)
half-lives were 69 to 135 days.
For low application rates (<100 Ug/g) 2,4-D Ou et al., 1978
degradation is favored by moisture and soil (p. 246)
organic matter.
Bacteria are the major organisms responsible Ou et al., 1978
for 2,4-D degradation in soils, and (p. 246)
low soil pH will significantly reduce 2,4-D
degradation rates.
Solubility: 540 mg/L at 20°C (in water) MAS, 1977
(p. 493)
2,4-D is chemically stable, but its esters NAS, 1977
are rapidly hydrolyzed to the free acid. (p. 493)
From Che available data, 2,4-D does not appear U.S. EPA, 1981
to be persistent in the environment. 2,4-D is (p. 1-1)
rapidly photolytically degraded in both air and
water and does not sorb significantly to soils
or sediments.
Molecular weight: 221.04 U.S. EPA, 1981
Melting point: 104-141°C (p. 3-2)
Boiling point: 106°C
Density: 1.57 at 30°C
Formula:
4-6
-------
TABLE 4-1. PHYTOTOXICITY OP 2,4-DICHLOROPHENOXYACETIC ACID
Plant/tissue
Tomato
Kidney beans
I Laeenana sp.
>j
Pea seedlings
Wheat seedlings
Chemical Form
Appl ted
2,4-D
NH4 2,4-D
2,4-D
2,4-D
2,4-D
Growth
Medium
soil
soil
soil
paper
petri dish
Experimental
Concentration"
(mg/L)
5-300
66-1000
500
1.5-50
0.01-100
Effects
Stem bending, increased
cell division adventi-
tious roots, parthenocarpy
Stomatal closure
Reduction of chlorophyll
a and b
tumor-like formations in
radicle and hypocotyl
21-98Z reduction in root
growth
19-71Z reduction in shoot
growth
References
U.S. EPA, 19B1 (Table 9-1)
U.S. EPA, 1981 (Table 9-15)
a Solution concentration to soil or to germination substrate (paper).
-------
TABLE 4-2. TOXICITY OF 2,4-DICHLOROPHENOXYACETIC ACID TO DOMESTIC ANIMALS AND WILDLIFE
Species
Cattle
Cattle
Sheep
Chickens
.p-
i Pheasant
CO
Quail
Mule Deer
Dog
Rat
Rat
Chemical Form
Fed
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
2,4-D
Peed
Concentration
(ug/g)
2,000
NRa
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Daily Intake
(mg/kg)
NR
<10
300-300
900
NR
668
400-800
8
100
20
30
300
Duration
of Study
28 days
106 doses
9 doses
28 days
single dose
21 days
single dose
single does
single does
NH
NH
18-49 days
4 weeks
4 weeks
Effects
Anorexia and weight loss
Normal post mortem
Lethal
Anorexia and weight loss
LDjQ. No adverse effects
LD50
LD50
LD50
No adverse effects
LD50
75Z mortality
No effect
Gastrointestinal
irritation
References
U.S. EPA, 1981
(Table 10-1)
U.S. EPA, 1981
(Table 10-1)
U.S. EPA, 1981
(Table 10-1)
U.S. EPA, 1981
(Table 10-1)
Tucker and Crabtree,
1970 (p. 40)
Tucker and Crabtree,
1970 (p. 40)
Tucker and Crabtree,
1970 (p. 40)
HAS, 1977 (p. 496)
HAS, 1977 (p. 496)
aNR = Not reported.
-------
TABLE 4-3. TOXICITY Of 2,4-DICHLOROPHENOXYACETIC ACID TO SOIL BIOTA
Chemical Form
Species Applied
Breeder earthworms 2,4-D
Nematodes 2,4-D
Coccinellid beetles 2,4-D
vo Soil bacteria 2,4-D
Soil fungi 2,4-D
Rhizobium 2,4-D
Soil microbes 2,4-D
Soil microbes 2,4-D
Soil
Type
lab
lab
NRa
Thornton's
Medium
aoi 1
soil
sandy loam
loam
Soil
Concentration
(UB/B)
0.1-1000b
100C
~
125
100
2
10-200
10-200
Application
Rate
(kg/ha) Effects
0.1-100 no effect,
at 1000 ug/g
100Z mortality
LD50
1.68 Sluggish behavior
Inhibited soil bac-
teria at pH 5.6
but not at pH 6.4
— Increased fungi
population
Inhibited some species
No inhibition of
electron transport
system
Significantly inhibited
electron transport
system at all levels
References
U.S. EPA, 1981
(p. 11-9)
U.S. EPA, 1981
(p. 11-9)
Pimentel and Goodman,
1974 (p. 42)
Newman and Downing,
1958 (p. 352)
Trevors and Starodub,
1983 (p. 596)
a NR - Not reported.
b In solution - immersed for 2 hours.
c In solution - immersed for 48 hours.
-------
SECTION 5
REFERENCES
Abramowitz, M., and I. A. Stegun. 1972. Handbook of Mathematical
Functions. Dover Publications, New York, NY.
American Conference of Governmental Industrial Hygienists. 1983.
Threshold Limit Values for Chemical Substances and Physical Agents
in the Work Environment with Intended Changes for 1983-84. Second
Printing. Cincinnati, OH. 93 pp.
Camp Dresser and McKee, Inc. 1984a. Development of Methodologies for
Evaluating Permissible Contaminant Levels in Municipal Wastewater
Sludges. Draft. Office of Water Regulations and Standards, U.S.
Environmental Protection Agency, Washington, D.C.
Camp Dresser and McKee, Inc. 1984b. A Comparison of Studies of Toxic
Substances in POTW Sludges. Prepared for the U.S. EPA Under
Contract No. 68-01-6403. Annandale, VA. August.
Donigian, A. S. 1985. Personal Communication. Anderson-Nichols & Co.,
Inc., Palo Alto, CA. May.
Food and Drug Administration. 1979. Compliance Program Report of
Findings FY78 Total Diet Studies-Adult (7305-003). Bureau of
Foods, Washington, D.C.
Food and Drug Administration. 1980. Compliance Program Report of
Findings FY77 Total Diet Studies-Adult (7320.73). Bureau of Foods,
Washington, D.C.
Freeze, R. A., and J. A. Cherry. 1979. Groundwater. Prentice-Hall,
Inc., Englewood Cliffs, NJ.
Gelhar, L. W., and G. J. Axness. 1981. Stochastic Analysis of
Macrodispersion in 3-Dimensionally Heterogeneous Aquifers. Report
No. H-8. Hydrologic Research Program, New Mexico Institute of
Mining and Technology, Soccorro, NM.
Gerritse, R. G., R. Vriesema, J. W. Dalenberg, 'and H. P. DeRoos. 1982.
Effects of Sewage Sludge on Trace Element Mobility in Soils. J.
Environ. Qual. 2:359-363.
Griffin, R. A. 1984. Personal Communication to U.S. Environmental
Protection Agency, ECAO - Cincinnati, OH. Illinois State
Geological Survey.
Hassett, J. J., W. L. Banwart, and R. A. Griffin. 1983. Correlation of
Compound with Sorption Characteristics of Non-polar Compounds by
Soils and Sediments: Concepts and Limitations. Chapter 15. In:
Francis, C. W. and I. Auerbach (eds.). The Environment and Solid
Waste Characterization, Treatment and Disposal. Butterwork
Publishers, Boston, MA.
5-1
-------
Johnson, R., and D. Manske. 1976. Pesticide Residues in Total Diet
Samples (IX). Pest. Monit. J. 9(4):157-159.
Jones, A., and G. F. Lee. 1977.' In; Risk Assessment and Health
Effects of Land Application of Municipal Wastewater and Sludges.
Sagik, B., and C. Sorber, (eds). Center for Applied Technology,
University of Texas at San Antonio, p. 52.
Lui, D., W. M. Strachan, K. Thomson, and K. Kwasniewska. 1981.
Determination of the Biodegradability of Organic Compounds. Env.
Sci. & Tech. 15(7):788-793.
Manske, D., and R. Johnson. 197S. Pesticide Residues in Total Diet
Samples (VIII). Pest. Monit. J. 9(2):94-105.
Nash, R., and W. Harris. 1973. Screening for Phytotoxic Pesticide
Interactions. J. Env. Qual. 2(4):493-497.
National Academy of Sciences. 1968. Effects of Pesticides on Fruit and
Vegetable Physiology. Vol. 6 of Principles of Plant and Animal
Pest Control. Publication 1968.
National Academy of Sciences. 1977. Drinking Water and Health.
National Research Council Safe Drinking Water Committee, NAS,
Washington, D.C.
Newman, A., and C. Downing. 1958. Herbicides and the Soil. J. Agric.
Food Chem. 6(5):352-3.
•Ou, L., D. F. Rothwell, U. B. Wheeler, and J. M. Davidson. 1978. The
Effect of High 2,4-D Concentration of Degradation and Carbon
Dioxide Evolution in Soils. J. Env. Qual. 7(2):241-246.
Pettyjohn, W. A., D. C. Kent, T. A. Prickett, H. E. LeCrand, and F. E.
Witz. 1982. Methods for the Prediction of Leachate Plume
Migration and Mixing. U.S. EPA Municipal Environmental Research
Laboratory, Cincinnati, OH.
Pimentel, D., and N. Goodman. 1974. Environmental Impact of
Pesticides. In; Khan, M., (ed.). Survival in Toxic Environments.
Academic Press, NY.
Sikora, L. J., W. D. Burge and J. E. Jones. 1982. Monitoring of a
Municipal Sludge Entrenchment Site. J. Environ. Qual. 2(2):321-
325.
Trevors, J., and M. Starodub. 1983. Effect of 2,4-D on Electron
Transport System (ETS) Activity and Respiration in Soil. Bull Env.
Contarn. Toxicol. 31:595-598.
Tucker, R., and D. Crabtree. 1970. Handbook of Toxicity of Pesticides
to Wildlife. Bureau of Sport Fisheries and Wildlife. Res. Pub.
No. 84.
5-2
-------
U.S. Environmental Protection Agency. 1976. Quality Criteria for
Water. Washington, D.C.
U.S. Environmental Protection Agency. 1977. Environmental Assessment
of Subsurface Disposal of Municipal Wastewater Sludge: Interim
Report. EPA/530/SW-547. Municipal Environmental Research
Laboratory, Cincinnati, OH.
U.S. Environmental Protection Agency. 1980. 2,4-Dichlorophenoxyacetic
Acid (2,4-D): Hazard Profile. Revised by Environmental Criteria
and Assessment Office, Cincinnati, OH. Prepared by Center for
Chemical Hazard Assessment, Syracuse Research Corp., Syracuse, NY.
14 pp.
U.S. Environmental Protection Agency. 1981. Criteria Document for 2,4-
Dichlorophenoxyacetic Acid. SRC TR-81-S86. Cincinnati, OH.
Prepared by Syracuse Research Corporation, Syracuse, NY.
U.S. Environmental Protection Agency. 1982. Draft Interim Criterion
Statement: Chlorophenoxy Herbicides. Ambient Water Quality
Criterion for the Protection of Human Health. Internal Review
Draft CIN-82-D005. Prepared for Criteria Standards Division Office
of Water Regulation and Standards. Environmental Criteria and
Assessment Office, Cincinnati, OH. 44 pp.
U.S. Environmental Protection Agency. 1983. Rapid Assessment of
Potential Groundwater Contamination Under Emergency Response
Conditions. EPA 600/8-83-030.
5-3
-------
APPENDIX
PRELIMINARY HAZARD INDEX CALCULATIONS FOR 2,4-DICHLOROPHENOXYACETIC
ACID IN MUNICIPAL SEWAGE SLUDGE
I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING
Based on the recommendations of the experts at the OURS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
II. LANDFILLING
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 esti-
mates initial dilution in the aquifer to give the initial con-
centration, C0, for the saturated zone assessment. (Conditions
for B, minimum thickness of unsaturated zone, have been set
such that dilution is actually negligible.) The saturated zone
assessment procedure is nearly identical to that for the unsat-
urated zone except for the definition of certain parameters and
choice of parameter values. The maximum concentration at the
well, Cmax, is used to calculate the index values given in
Equations 4 and 5.
B. Equation 1: Transport Assessment
C(y.t) »i [exp(AL) erfc(A2) * exp(B1) erfc(B2>]
Co
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:
Al - X_ [V* - (V*2 + 4D* x
Al 2D*
A-l
-------
Y - t (V*2 * AD*" x
A2 = (4D* x t)±
B. « *_ [V* + (V*2 + 4D* x
Dl
_ Y + t (V*2 + AD* x U*)*
82 " (4D* x t)±
and where for the unsaturated zone:
C0 = SC x CF = Initial leachate concentration (pg/L)
SC = Sludge concentration of pollutant (mg/kg DW)
CF = 250 kg sludge solids/in-* leachate =
PS x 103
1 - PS
PS = Percent solids (by weight) of Landf illed sludge
20Z
t = Time (years)
X = h = Depth to groundwater (m)
D* = a x V* (m2/year)
a = Dispersivity coefficient (m)
V* = — 9 — (m/year)
0 x R
Q = Leachate generation rate (m/year)
6 = Volumetric water content (unitless)
R = 1 + lll x KJ = Retardation factor (unitless)
0
P
-------
0 = Aquifer porosity (unitless)
R = 1 + drv x Kd = Retardation factor = 1 (unitless)
since K 9 * " * • and B > 2
— K x i x 365 —
Equation 3. Pulse Assessment
P(X,t) for 0 <. t <. t
,t) - P(x,t - t0) for t > t(
to (for unsaturated zone) = LT = Landfill leaching time
(years)
t0 (for saturated zone) = Pulse duration at the water
table (x = h) as determined by the following equation:
tn = [ / C dt] * C
P(X»C) = i as determined by Equation 1
co
A-3
-------
E. Equation 4. Index of Groundvater Concentration Resulting
from Landfilled Sludge (Index 1)
1. Formula
Index 1 = Cmax
where:
= Maximum concentration of pollutant at well =
maximum of C(A£,t) calculated in Equation 1
(Ug/D
2. Sample Calculation
0.0186 Ug/L = 0.0186 Ug/L
P. Equation 5. Index of Human Toxicity Resulting from
Groundwater Contamination (Index 2)
1. Formula
(Ii x AC) + DI
Index 2 =
where:
Ij = Index 1 = Index of groundwater concentration
resulting from Landfilled sludge (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
, ,,A in-4 - (0.0186 Ug/L x 2 L/day) + 2.81 Ug/day
3'25* * 10 " 8750 Ug/day
III. INCINERATION
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
IV. OCEAN DISPOSAL
Based on the recommendations of the experts at the OWRS meetings
(April-May, 1984), an assessment of this reuse/disposal option is
not being conducted at this time. The U.S. EPA reserves the right
to conduct such an assessment for this option in the future.
A-4
-------
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, Pdry (g/mL)
Volumetric water content, 6 (unitless)
Fraction of organic carbon, foc (unitless)
Site parameters
Leachate generation rate, Q (m/year)
Depth to grounduater, h (m)
Dispersivity coefficient, a (m)
Saturated zone
Soil type and characteristics
Aquifer porosity, 0 (unitleae)
Hydraulic conductivity of the aquifer,
K (m/day)
Site parameters
Hydraulic gradient, i (unitless)
Distance from well to landfill, A 8. (m)
Dispersivity coefficient, a (m)
1
4.64
1.53
0.195
0.005
0.8
5
0.5
0.44
0.86
0.001
100
10
2
7.16
1.53
0.195
0.005
0.8
5
0.5
p. 44
0.86
0.001
100
10
3
4.64
1.925
0.133
0.0001
0.8
5
0.5
0.44
0.86
0.001
100
10
4 5
4.64 4.64
NA° 1.53
NA 0.195
NA 0.005
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
4.64
1.53
0.195
0.005
0.8
5
0.5
0.44
0.86
0.02
SO
5
7 B
7.16 N"
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 M
-------
TABLE A-l. (continued)
Condition of Analysis
Results
Unsaturated zone assessment (Equations 1 and 3)
Initial leachate concentration, C0 (iig/L)
Peak concentration, Cu (|ig/L)
Pulse duration, to (years)
Linkage assessment (Equation 2)
Aquifer thickness, B (a)
Initial concentration in saturated zone, C0
(UB/D
1
1160
170.8
5.001
126.0
171.0
2
1790
263.6
5.001
126.0
264.0 .
3
1160
295.0
4.999
126.0
295.0
4
1160
1160
5.000
253.0
1160
5
1160
170.8
5.001
23.80
171.0
6
1160
170.8
S.001
6.320
171.0
7
1790
1790
5.000
2.380
1790
8
N
N
N
N
N
Saturated zone assessment (Equations 1 and 3)
Maximum uell concentration, Cmax (lig/L)
Index of groundwater concentration resulting
from landfilled sludge. Index 1 (|ig/L)
(Equation 4)
Index of human toxicity resulting from
groundwater contamination, Index 2
(unitless) (Equation 5)
0.0186
0.0186
0.0287
0.0287
0.0003254 0.0003277
0.0321
0.0321
0.0003285
0.1261
0.1261
0.00035
0.0987
0.0987
0.0003437
0.7435
0.7435
41.43
41.43
0.0004911 0.009791 0.0003211
aN - Null condition, where no landfill exists; no value is used.
bNA = Not applicable for this condition.
------- |