United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-85/053 Sept. 1985
&ERA Project Summary
Determination and Prediction of
Chemical Forms of Trace
Metals in Sewage Sludge and
Sludge-Amended Soils
L. J. Lund, G. Sposito, and A. L. Page
A computer program. GEOCHEM,
was developed to calculate trace metal
equilibria in soil solutions affected by
the application of sewage sludges. The
structure of the program, data required.
and typical applications of metal speci-
ation in aqueous extracts from munici-
pal sewage sludges and sludge-
amended soils are described and
discussed.
Fulvic acids extracted from sewage
sludge were found to contain 20 to 40
times more sulfur than fulvic acids
extracted from soil organic matter. Sul-
fonyls and surfhydryls therefore play a
significant role in the complexation of
metals in sludges and probably also in
sludge-amended soils. The partitioning
of metals in the organic and inorganic
aqueous phases from sludge and
sludge-amended soils differs among
sludges. In general, Cu(ll) and Fe(lll)
show high preference for organic com-
plexation, and Cd, Ni, and Zn tend to
form inorganic complexes preferen-
tially. Following equilibrium of sludges
from seven treatment plants with three
soils for a period of 50 weeks at 1 /3 bar
saturation, essentially all of the soluble
Cu was organically complexed, and
most of the soluble Cd, Ni, and Zn were
present in solution as the free divalent
ion.
A procedure to fractionate sludges
into various chemical forms was devel-
oped. The procedure consisted of
extraction with KNO3 (exchangeable),
followed by distilled, deionized water
(adsorbed). 0.5 M NaOH (organically
bound), Na2 EDTA (carbonate), and
HNO3 (sulfide-residual). The distri-
bution of metals in various forms fol-
lowing equilibration of soils with
sludges is presented and discussed. In
general, only very small percentages of
the total quantity of metals in sludge-
amended soils occur in soluble, exchan-
geable, or adsorbed forms.
This Project Summary was developed
by EPA's Water Engineering Research
Laboratory, Cincinnati. OH. to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The use of land for the disposal or recy-
cling of municipal sewage sludges has
increased during the past decade and is
continuing to grow. Sewage wastes are
receiving increased attention for use as
phosphorus fertilizers, supplemental nit-
rogen fertilizers, and soil conditioners.
Evidence exists that trace metals in
sludge-amended soils are toxic to a
number of plant species, are accumu-
lated by many types of vegetation, and
may be a source of surface water and
groundwater contamination. The basic
chemistry of trace metals in sewage
sludges and sludge-amended soils thus
needs to be fully understood. The reac-
tion rates, mechanisms, and products of
trace metals following their application to
soils in the form of sewage sludge are not
well known. The soluble and insoluble
forms in sludge-amended soils will be
important in determining plant availabil-
-------
ity, toxicity, and mobility of trace metals.
This project investigated the chemical
forms of five trace metals (Cd, Zn, Ni, Cu,
and Pb) in municipal sewage sludges and
the changes that occur in them following
sludge application to soil as influenced by
time, sludge source, soil characteristics,
and solution composition. This informa-
tion will help determine conditions under
which sludges can be safely recycled on
agricultural land, and it will aid in the
selection of the most desirable soils for
disposal of sludges. The data will also
serve as a basis for determining potential
degradation of soils and waters by sludge
application to land.
Sewage wastes vary greatly with the
treatment plant, the time spent at any
one treatment plant, and the treatment
process. Because anaerobically digested
sludges represent the highest percen-
tage of those generated in the United
States, this project emphasizes anaerobi-
cally digested sludge. Because of varia-
tions in the trace metal contents of
sludge from different treatment facilities,
sludges from a number of wastewater
treatment plants were investigated.
Description of GEOCHEM
GEOCHEM is a computer program that
enables the calculation of trace metal
equilibria in soil solutions of widely vary-
ing compositions. The program was
developed and tested for use with sludge-
amended soils. The method of calculation
is based on chemical thermodynamics. A
mole balance equation is set up for each
component of a soil solution and thermo-
dynamic equilibrium constants corrected
for ionic strength are incorporated into
the various terms of this equation accord-
ing to the law of mass action. The solu-
tion of the set of nonlinear algebraic
equations that results from simultane-
ously applying mole balance to all the
components ultimately provides the con-
centration of each dissolved, solid, or
adsorbed species i n the soiI system under
consideration.
Applications of GEOCHEM
Some typical applications of GEO-
CHEM would include: (1) predicting the
concentrations of inorganic and organic
complexes of a metal cation in a soil solu-
tion, (2) calculating the concentration of
a particular chemical form of a nutrient
element in a solution bathing plant roots
so as to correlate that form with nutrient
uptake, (3) predicting the fate of a pollu-
tant metal added to a soil solution of
known characteristics, and (4) estimat-
ing the effect of changing pH, ionic
strength, redox potential, water content.
or concentration of some element on the
solubility of a chosen chemical element
in a soil solution.
To illustrate the application of GEO-
CHEM, Table 1 lists the analytical data for
a saturation extract of an Altamont soil
amended with sewage sludge and
CdS04 . In this example, there were 9
metals (including H+ and 15 ligands
(including OH") that could form 261 dif-
ferent complexes according to the ther-
modynamic data in the program. The
output from a GEOCHEM subroutine for
the data in Table 1 appears in Table 2. The
percentage distribution figures for the
metals and ligands constitute considera-
ble worthwhile information, but what
stands out is the strong complexation of
Cu(ll) and Fe(lll) by the organic ligands
and the relative lack of complexation of
Cd, Mn(ll), and Zn. The major cations, Ca,
Na, and K, are involved principally with
the inorganic part of the system, whereas
Cu(ll) and Fe(lll) are involved principally
with the organic part. The remaining
minor cations Cd, Mn(ll), and Zn, fall
somewhere in between.
Results
Analytical Properties of the
Fulvic Acid Fractions of
Three Sludges
An understanding of the mechanisms
through which sewage sludges incorpo-
rated in soil form water-soluble com-
plexes with trace metals should provide a
basis for predicting and controlling levels
of these metals in the soil solution. In
view of the existing literature on metal
complexation by components of natural
soil organic matter, it is reasonable to
suggest that the fulvic acid fraction of
sludge and of sludge-amended soil would
be a major ligand for the complexation of
trace metals. The fulvic acid fractions of
three sludges were, therefore, extracted,
purified, and then studied for their ana-
lytical properties. The main difference
between the fulvic acids extracted from
sewage sludge (SS fulvic acids) and the
fulvic acids extracted from soil, organic
matter (SOM fulvic acids) is that the
former contain 20 to 40 times more S
than a typical fulvic acid extracted from
natural soil organic matter (Table 3). Two
of the SS fulvic acids also had somewhat
less oxygen than a typical SOM fulvic
acid. The principal conclusions to be
drawn from these data are that SS fulvic
acids can show significant variability in
their chemical compositions, but that S-
containing components should exert an
important influence on their chemistry in
any case.
Ultraviolet and visible spectra of the SS
fulvic acids suggested thatthey consist of
highly aromatic and condensed struc-
tures, somewhat comparable with those
in SOM humic acids. The aromatic nature
of the SS fulvic acids could be inferred
indirectly from their X-ray diffraction
patterns, which yielded a y -band cen-
tered more nearly at 4 than 5A, thus
implying a relatively small content of ali-
phatic components.
Partitioning of Metals after
Sludge Incorporation into Soil
At present, the chemical mechanisms
by which potentially harmful trace metals
in sewage sludges become soluble spe-
cies after the incorporation of sludge into
soil are not well defined. However, data
obtained in this study show that the
Table 1. Analytical Data for a Saturation Extract of an Altamont Soil Amended with Sewage
Sludge and CdSOS
Component pCf Component
Ca
K
Na
Fe(lll)
Mn(ll)
Cu(ll)
Cd
Zn
CO
so.
Cl
2.07
3.70
3.00
4.75
4.70
5.72
5.85
5.13
2.70
2.70
2.28
P04
N03
Citrate^
Salicylate J
Phthalate J
Arginine $
Ornthine t
Lysine \
Valine J
Maleate J
Benzylsulfonate |
4.00
2.77
4./4
4.27
3.97
4.49
4.36
4.36
4.36
3.97
4.27
» pH=6.30.
f pC = - log [ ], where [ ] refers to a molar concentration.
t Collectively considered organics in Table 2.
-------
Table 2. Output from GEOCHEM Giving Primary Distribution of Metals and Ligands for Sludge-Amended Altamont Soil
Free
Metal or
Ligand
Ca
K
Na
Fe(lll)
Mn
Cuflll
Cd
Zn
C°3
so3.
Cl
P04
NO3
Organics
Metal or
Ligand
88.6
99.0
98.8
77.8
0.3
62.2
69.9
69.8
98.4
93.2
17.9
Bound With
H
96.6
77.2
58.2
Ca
2.6
29.6
1.6
22.3
0.8
21.3
Na
0.5
0.1
2.2
Fe(lll)
0.5
0.02
Mn Cu(ll) Zn
_ _ _
_ _ _
0.1
_
0.3 - -
_ _ _
0.3 0.01
C03
0.6
0.1
20.6
11.9
0.1
1.7
18.5
so.
6.9
0.6
0.9
6.1
4.9
6.9
Cl
1.0
0.2
17.2
0.1
P04
0.3
1.4
0.5
0.7
N03
0.6
0.3
0.1
1.4
1.1
Organics
0.19
79.3
2.2
99.2
12.4
3.7
Table 3. Ultimate Analyses* of SS Fulvic Acids and SOM Fulvic Acids
Fulvic
Acid
Component
C
H
N
ot
S
Sludge A
30.3 ± f.7f
5.20 ±0.76
1.77 ±0.18
51.1
11. 56 ±0.95
SS Fulvic Acid
Sludge B1
45.2 ± 3.0
7.31 ± 0.28
3.06 ± 0.06
40.0
4.46 ± 0.65
Sludge C
46.95 ± 0.84
7.21 ± 0.05
3.67 ± 0.14
35.7
8.44 ± 0.42
SOM
Fulvic Acids
40-55
1.5 - 7.0
0.7 - 3.5
39-50
0.1 -3.6
* Percentage, water- and ash-free basis.
f Mean deviation computed on data for three different samples of fulvic acid.
t Calculated by difference: %O-100-% CC+W+/V+S/
organic constituents of sludges play a
significant role in the speciation of
metals such as Cd, Cu, Ni, Pb, and Zn. The
degree to which soluble complexes
between these metals and sludge-
derived organic compounds actually form
in a soil solution depends on the func-
tional group character and the water sol-
ubility of the organics, as well as on the
number and stability of other possible
trace metal compounds and surface
phases.
The association of five trace metals
with the organic and inorganic fractions
was studied by eluting sludge-FA from
Sephadex G-10 columns.
An elution diagram for a metal-SS ful-
vic acid solution is shown in Figure 1 as
an example of these studies. The relative
concentrations of fulvic acid, Ni, and Cl
vary with elution volume, and relation-
ships between these concentrations can
be used to infer something about metal
complexes present. Results showed that
the partition of metals among organic
and inorganic forms differs among
sludges. In general, Cu and Fe(lll) show
high preference for organic complexa-
tion, while Cd, Ni, and Zn tend to form
inorganic complexes preferentially.
These kinds of differences reflect clearly
the fact that the complicated, hetero-
geneous nature of sludge-derived fulvic
acid makes for a detailed scheme of metal
binding that will depend on the exact
molecular composition of a given sludge.
Incubation Studies to Evaluate
Changes in Soils after Sludge
Amendment
A number of factors such as aeration
and soil characteristics are known to
affect the decomposition of organic
materials and the fate of the constituents
of the organic materials. For a fuller eva-
luation of the changes that take place
when sewage sludge is added to soils, a
series of incubation experiments was
carried out. In the first study, three soils
were amended with Ontario sludge. Re-
covery of added trace metals by HNO ,
DTPA (diethylenetriaminepentaacetate),
and HOAc (acetic acid) was significantly
affected by water content, sample prepa-
ration, and soil. Application rate was gen-
erally not a significant factor.
This work demonstrated that for soil
amended with Ontario sludge, metal
extractability varied with time, water
content, sample preparation, soil, and
extractant. However, these results were
only for one sludge. To determine the
effects of these treatments more fully,
additional studies were conducted using
seven sludges representing a range of
characteristics.
The factors and levels used in this
study were sludges (7), incubation water
contents (1/3 bar and saturated), soils
(Baywood, Delhi, and Calhi), sample
preparation (wet and air-dried), times (7),
and extractants (HNO3), DTPA, and sat-
uration extracts). A constant rate of 100
T/ha was used, because in the previous
study, rate did not affect the recovery of
metals by HN03 or DTPA. The mean re-
covery of the trace metals (Cd, Cu, Ni, and
Zn) added to soils in sludges by extraction
with 4/V HNO, was essentially complete
(>90%). On the average, metal recovery
by DTPA was 38%less than half that of
HNO3. The recovery of metals by DTPA
varied from 34% for Pb to 43% for Zn.
Incubation time (1 to 52 weeks) had
essentially no effect on the amounts of
metals extracted from the sludge-
amended soils by DTPA. Metal extracta-
bility was significantly less for samples
incubated at saturation than for samples
incubated at 1/3 bar water content.
Saturation extracts of sludge-amended
soils incubated for 50 weeks were ana-
lyzed for cationic and anionic composi-
tion. These data were analyzed using
GEOCHEM to predict the forms of the
trace metals in the soil solutions. Data for
Cd are used to illustrate the results
(Table 4).
Cadmium was found to be present in
the extracts principally as free ionic
forms, with smaller percentages present
as organically complexed. For samples
incubated at 1 /3 bar, the only real excep-
tion to this result was for the LA liquid
sludge, in which inorganically complexed
-------
120
150
200
Elution Volume, ml
250
300
Figure 1. Elution diagrams for Ni in metal-fulvic acid solutions
Cd accounted for the greatest proportion
of Cd in the extracts. Incubation at satu-
ration resulted in a shift in form from free
ionic to organically complexed. This
result occurred in every case where Cd
was detectable in the saturation extracts
of the samples incubated at saturation.
Fractionation Procedure
A fractionation procedure was devel-
oped and used on sludge-amended soils
to estimate the proportion of selected
trace metals in various forms. The proce-
dure consisted of extraction with KN03
(exchangeable) followed by distilled-
deionized water (adsorbed), 0.5 M NaOH
(organically bound), Na, EDTA (carbon-
ates), and HNO3 (sulfide residual). The
use of distilled water to remove adsorbed
metals was evaluated with freshly pre-
pared Fe and Al hydrous oxide gels (Table
5). Close to 100% recoveries of sorbed
metals were obtained for metals (Cd, Ni,
and Zn) having the least affinity for
adsorption by the hydrous oxides. The
lowest recoveries (approximately 80%)
were observed for Cu, which had the
greatest affinity for both Fe and Al gels.
Recovery of Pb from the Fe gel was also
low. Recovery for each metal was virtu-
ally independent of the amount of
adsorbed metal present at the onset of
the extraction. These data suggested that
the use of three sequential deionized
water washings forms a reliable basisfor
the extraction of adsorbed metals from
sludges and sludge-amended soils.
The standard procedure for removal of
fulvic and humic acid fractions of organic
matter is by extraction with NaOH. This
extractant was therefore used to evalu-
ate the proportion of organic-bound
metals. Data for the extraction of metals
from pure carbonates and sulfides indi-
cated that 0.5 M NaOH should be reason-
ably specific to the extraction of
organic-bound metals (Table 6). Only
with Pb and Zn were significant quanti-
ties of each metal carbonate brought into
solution by 0.5 M NaOH. The use of a
single 0.05 M NaEDTA extraction was
generally specific to carbonate-bound
metals. Only small proportions of the
metals were extracted from the metal
sulfides using this reagent. Essentially
complete recovery of metals from the cor-
responding metal sulfides was achieved
only after extraction with 4/V HNO at
80°C (Table 6).
Table 4. Speciation of Cd in Saturation Extracts of Sludge-Amended Soils After 50 Weeks of Incubation (percent of total)
Incubation
Water
Content Soil Species
1/3 Bar Bay wood F*
1
O
Delhi F
1
0
Calhi F
1
0
Saturation Baywood F
1
0
Delhi F
1
O
Calhi F
1
O
Rialto
58.6
22.0
19.1
75.2
20.6
4.2
75.7
19.9
4.1
-t
33.3
34.9
31.7
39.1
17.0
40.9
LA Compost
68.1
29.8
2.0
72.0
26.0
1.7
71.4
25.9
2.6
41.8
14.8
43.2
Colton
52.0
23.5
24.3
74.0
19.7
6.2
70.2
18.9
10.7
33.4
40.5
25.6
Sludge
Ontario
70.9
26.0
3.1
71.0
22.2
6.6
68.4
21.0
10.3
24.8
6.2
69.0
30.3
30.3
39.2
Escondido
54.4
36.5
9.0
67.8
29.5
3.0
64.2
31.7
3.9
41.7
23.4
34.8
42.4
26.4
31.1
LA Liquid
37.6
58.0
4.3
42.9
54.9
2.0
41.2
52.5
5.3
24.8
60.0
14.9
31.9
43.1
25.0
26.3
58.0
15.6
Kokomo
73.3
23.1
3.5
79.7
15.9
4.2
72.2
23.4
4.4
61.1
29.3
9.6
52.7
31.8
15.4
* F = free ionic; I = inorganically complexed; O = organically complexed.
f Indicates metal concentration below detection limit.
-------
Table S. Water Extraction (3X) of Metals Absorbed by Fe and Al Hydrous Oxide Gels
Metal
FeGel
AIGel
Sorbed Extracted
Percent
Recovery
Sorbed Extracted
Percent
Recovery
(tig/0.05 g gel)
(ug/0.05 g gel)
Cd
Cu
Ni
Pb
Zn
21.2
40.0
50.0
99. 4
25.2
37.6
50.0
100.0
38.0
64.6
21.8
41.2
41.0
93.5
26.2
38.0
41.4
80.6
36.4
63.1
102
103
82
94
104
101
83
81
96
98
6.2
16.0
48.8
97.6
14.6
28.0
44.0
89.6
38.6
73.0
6.5
16.6
36.1
81.0
14.3
24.4
45.5
91.6
38.8
69.8
105
104
74
83
98
87
103
102
101
96
Table 6.
Extractant
Percent Recovery of Metals During NaOH. EDTA. and HNOa Extraction of 0.03 g of
Pure Metal Carbonates and Sulfides
Metal Extracted
Cd
Cu
Ni
Pb
Zn
0.5 M NaOH
0.05 M EDTA
0.5 MNaOH
0.05 M EDTA
2 N HN03
4NHN03.80°C
0
99
0
4.3
16.3
98.7
1.1
100
1.3
3.3
0
47.5
Carbonate
0
1OO
Sulfide
0
15
46.2
100
38.5
85.1
8.8
20
44.9
100
33.2
100
0
0
94.0
1OO
amounts of sulfide-bound Cd relative to
the amount of Cd in this form after incu-
bation at saturation. Furthermore, for the
Calhi and Delhi soils, the amounts of
sulfide-bound Cd after 1/3-bar incuba-
tion were usually lower than those
observed for the whole sludges.
In the case of the Kokomo sludge,
which had a very high (81 %) proportion of
Cd in the carbonate fraction, there was
tendency for Cd to be redistributed into
the organic-bound and adsorbed frac-
tions during incubation. In fact, adsorbed
Cd at detectable levels was observed only
in the case of incubation with Kokomo
sludge.
No detectable, exchangeable Cd was
observed after incubation of any of the
sludge-amended soils, reflecting the
absence of this form in the whole
sludges. Where applied sludges resulted
in Cd contents above 2 (ig/g of soil, a
of soil, a significant proportion (0.1% to
2.2%) of the total Cd appeared in solution
after incubation at 1/3 bar.
The full report was submitted in fulfill-
ment of Grant No. R-804516 by the Uni-
versity of California under the
sponsorship of the U.S. Environmental
Protection Agency.
Again, the data for Cd are used as an
example of the results of applying this
fractionation procedure to sludge-
amended soils (Table 7). When the study
used sludges with a low Cd content
(Rialto, LA-composted, and Cotton),
which resulted in Cd contents of less
2 /ug/g for the sludge-amended soils, Cd
appeared almost exclusively in the
organic and carbonate forms for each soil
amended with these sludges. The ten-
dency was for the distribution to be
weighted in favor of the carbonate form
(14 out of 18 cases) despite the greater
proportion of Cd in the organic form in
two out of three sludges.
Though a small proportion of the total
Cd (7.3% to 17.1%) was present in the
Rialto, LA-composted, and Colton
sludges in the sulfide form, only in one
instance was Cd observed in this form
after incubation of the sludges with the
soils. In contrast, the absence of Cd in
exchangeable and adsorbed fractions in
the whole sludges was maintained after
incubation. Only in one instance (after
the incubation of Rialto sludge with the
Baywood soil at 1/3 bar) was any sub-
stantial quantity of Cd measured in the
soil solution. Only minor variations
occurred in the distribution of Cd for
these sludges as a result of the different
incubation conditions employed.
All but one of the remaining sludges
with higher Cd contents contained the
major portion of the total Cd in the carbo-
nate form after incubation with soil. In
the majority of the sludge-amended soils,
more than 60% of the Cd was in the car-
bonate form after incubation at both 1/3
bar and saturation. In only one case did
the proportion of Cd in this fraction fall
below 50%. In the Ontario and Escondido
sludges, the proportion of Cd in the car-
bonate form increased after incubation
with each soil at both moisture contents.
A general increase also occurred in the
amount of Cd in the sulfide fraction rela-
tive to the whole sludge following incu-
bation under saturated conditions. The
increases in the carbonate and sulfide-
bound fractions were made at the
expense of organic-bound Cd. Incubation
at 1 /3 bar resulted in appreciably lower
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Table 7. Distribution of Cd in Sludges and Sludge-Amended Soils as Affected by Incubation Water Content (% of total)
Sludge or Soil
and Form of Cd Riatto LA-Composted Cotton Ontario Escondido LA-Liquid Kokomo
Sludge:
Solution
Exchangeable
Adsorbed
Organic
Carbonate
Sulfide
Baywood:
Solution
Exchangeable
Adsorbed
Organic
Carbonate
Sulfide
Delhi:
Solution
Exchangeable
Adsorbed
Organic
Carbonate
Sulfide
Calhi:
Solution
Exchangeable
Adsorbed
Organic
Carbonate
Sulfide
* = None detected.
f = Saturated, 1/3 =
ND* ND ND NO NO ND ND
0
0
0 0 0 1.1 1.1
0000 0
66.0 32.0 65.5 36.6 32.8 7.0
26.4 50.9 34.5 51.6 53.3 81.0
7.6
st
0
0
0
44.6
55.4
0
0
0
0
53.3
46.7
0
0
0
0
54.3
45.7
0
1/3 bar saturation.
17.1 7.3 11.8 12.8 10.9
1/3 S 1/3 S 1/3 S 1/3 S 1/3 S 1/3 S 1/3
0.2 0 0 0 0 0 1.8 O 1.4 0 2.2 0 0.1
OOOOOOOOOOOOO
0 0 0 0 0 0 0 O 0 0 0 5.5 3.6
47.7 40.9 16.5 46.8 46.4 15.0 14.8 12.6 20.9 18.4 20.7 19.9 12.0
52.1 59.1 65.3 53.2 53.1 60.0 61.2 59.6 64.2 62.2 57.5 58.2 75.2
0 0 18.2 0 0 25.0 22.0 27.8 13.5 19.4 19.6 16.4 9.1
0 0 0 0 0 0 0.9 O 1.1 0 1.1 0 O.I
OOOOOOOOOOOOO
0 0 0 0 0 0 0 O 0 0 0 6.4 3.9
43.3 39.6 41.8 44.6 43.8 26.5 43.1 23.3 34.5 22.3 56.9 23.2 23.7
56.5 60.4 55.6 55.6 56.2 60.1 51.4 54.7 59.6 60.1 42.0 60.3 70.7
00000 13.4 4.6 22.0 4.8 17.6 0 10.1 1.6
0 0 0 0 0 0 0.5 O 0.3 0 1.0 0 O.2
OOOOOOOOOOOOO
0 0 0 0 0 0 0 0 0 0 0 1.8 2.7
50.0 42.6 44.0 53.5 41.3 14.6 39.0 11.5 19.8 11.7 22.7 5.1 3.8
50.0 57.4 56.0 46.5 58.7 70.6 60.5 61.4 79.9 77.8 65.2 76.2 92.0
00000 14.8 0 27.1 0 10.5 12.1 16.9 1.3
L J. Lund, G. Sposito, and A. L. Page are with University of California, Riverside,
CA 92521.
J. A. Ryan is the EPA Project Officer (see below).
The complete report, entitled "Determination and Prediction of Chemical Forms of
Trace Metals in Sewage Sludge and Sludge-Amended Soils," (Order No. PB
85-197 1 19/AS; Cost $20.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
U. S. GOVERNMENT PRINTING OFFICE:1985/559-l 11/20681
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Cincinnati OH 45268
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