Zn distribution in soils amended with different kinds of sewage sludge

Journal of Environmental Management 88 (2008) 1571–1579
Zinc distribution in soils amended with different kinds of sewage sludge
Silvana Irene TorriÃ, Rau´ l Lavado
Ca´tedra de Fertilidad, Facultad de Agronomıá, UBA, Avda San Martıń 4453, Buenos Aires C1417DSE, Argentina
Received 10 August 2006; received in revised form 7 July 2007; accepted 31 July 2007
Available online 24 September 2007
Abstract
Sewage sludge (SS) can be applied to cropland to supply and recycle nutrients and organic carbon. Potentially toxic elements in the
sludge, however, are of environmental concern. This study evaluates the changes in chemical speciation of Zn in three representative
pristine soils of the Pampas Region, Argentina, measured with sequential extraction over a one-year period. Pure SS or SS containing
30% (DM) of its own incineration ash (AS) was applied to the soils at an application rate of 150 Mg haÀ1
. Zn was sequentially
fractionated into exchangeable, organically bound, inorganic and residual fractions. The application of the SS and AS amendments
significantly increased Zn concentration in all soil fractions at each sampling date. At day 1, Zn was mainly found in the residual fraction.
A year after the application of the amendments, redistribution towards the inorganic fraction was observed (41–76% of total Zn
content). Zn found in exchangeable and inorganic fractions depended on soil pH rather than on the type of soil used. A negative and
significant correlation was found between exchangeable Zn concentrations and soil pH (r ¼ 0.94), and a positive and significant
correlation between inorganic Zn concentrations and soil pH (r ¼ 0.92). For each amended soil and sampling date, no significant
differences were observed between SS or AS treatments for the exchangeable fraction. Moreover, the use of AS did not cause significant
differences in Zn concentration in the other soil fractions compared to SS. Based on these results, land spreading of AS may be similar to
SS diaposal in terms of Zn mobility.
r 2007 Elsevier Ltd. All rights reserved.
Keywords: Ash; Chemical fractionation; Sewage sludge; Soil; Waste management; Zinc
1. Introduction
The disposal of sewage sludge (SS) on agricultural land is
increasing throughout the world. It is well known that SS
contains useful amounts of nutrients such as N and P, and
has valuable soil beneficial effects. Its organic matter
generally improves soil physical properties by increasing
water retention capacity and structural stability (Khan et
al., 2006). However, this practice has raised numerous
environmental and health issues because of the significant
concentration of potentially toxic elements (PTE), patho-
gens and organic pollutants commonly found in this
material (McBride et al., 1997). Agricultural land applica-
tion of SS is not a common practice in Argentina, where it
is presently discarded in non-agricultural soils as land-
farming after aerobic stabilization, and to a minor extent as
land filling. Incineration is not performed, although it is
worldwide considered an attractive method of simulta-
neous energy production and volume reduction. The ash
(AS) can also improve soil physical properties because of
its silt-size nature (Saikia et al., 2006) and can be an
effective liming agent (Zhang et al., 2002). Ashing SS also
prevents pathogen propagation and may largely reduce
organic pollutants. However, non-volatile hazardous con-
stituents commonly found in SS are concentrated in the AS
and potentially limit the extent of its land application.
These contaminants include PTE such as Cd, Cu, Cr, Ni,
Pb and Zn. For this reason, AS disposal could result in
environmental hazards associated with crop yield reduction
(Moreno et al., 1997), potential introduction into the food
chain (Winder et al., 1999), surface water pollution or
possible pollution of ground-water resources (Paramasi-
vam et al., 2006; Saikia et al., 2006).
Incinerated SS could be used as a soil amendment
combined with other waste materials. Mixing SS with its
ARTICLE IN PRESS
www.elsevier.com/locate/jenvman
0301-4797/$ - see front matter r 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jenvman.2007.07.026
ÃCorresponding author. Tel./fax: +54 01145248076.
E-mail address: torri@agro.uba.ar (S.I. Torri).

own AS offers a potential viable utilization of this organic
waste as a soil amendment, for the AS would offset soil
acidity that may arise through continued land application
of organic wastes (Zhang et al., 2002). The SS matrix may
also act as a major adsorptive medium for PTE (Corey
et al., 1987). Previous research has shown that several soil-
related factors, namely pH, organic matter (OM), clay
content, Mn and Fe oxides are likely to determine the
chemical associations of PTE in soils (Hesterberg, 1998).
Many studies have reported on the availability of PTE
arising through land application of SS or AS (Hseu, 2006;
Paramasivam et al., 2003). However, little work has been
conducted on the potential changes in bioavailability of
PTE that may arise through the application of this mixed
waste: PTE availability may increase as a result of the sum
of bioavailabilities of the SS and AS or may decrease
because of the interaction between the two amendments.
During recent decades various single and sequential
extraction schemes have been developed. The application
of sequential extraction techniques provides information
about the speciation of PTE in the environment and the
bioavailability, mobility and transformation between che-
mical forms in sludge-amended soils. Several sequential
extraction methods have been employed to partition metals
into fractions defined as soluble, exchangeable, organically
bound, precipitated, oxide bound and residual. Much
research has correlated PTE in these fractions with plant
concentration or uptake (Hseu, 2006; Obrador et al., 2003).
Zn is usually the most bioavailable PTE of sludge origin,
and plays an important role as an essential trace element.
Its deficiency in crop production is well known around the
world, and it is becoming increasingly significant in the
Pampas Region of Argentina (Urricariet and Lavado,
1999). The Pampas region covers 50 million ha, and is one
of the largest temperate field cropland areas of the
Southern Hemisphere. Dominant soils are Mollisols
developed on loess-like sediments deposited throughout
the late Pleistocene and the Holocene (Teruggi, 1957).
Buenos Aries City SS can be a valuable long-term source of
soil Zn (Rodriguez and Lavado, 2004). However, the
impacts of Zn accumulation in soils due to SS application
raise concern, as Zn phytotoxicity is considered to be more
frequent than Cd, Co, Cu, Ni or other PTE’s toxicity
(Chaney, 1993). Soil characteristics are likely to determine
the chemical associations of Zn, since they are closely
connected to the chemical processes of precipitation,
sorption and complexation (Meers et al., 2006; Vijver
et al., 2003). As soil pH falls, Zn solubility and uptake
increases (Anguissola Scotti et al., 1999). Soil-specific Zn
adsorption capacity is also important, being higher on
clayey than on sandy soils at equal soil pH and total Zn
concentration (Alloway, 1990). At high sludge application
rates, sludge adsorption sites control Zn bioavailability
(Chaney, 1993). When sludge addition ends, the lack of
fresh OM and the decomposition of the OM previously
added may result in large changes in Zn bioavailability due
to changes in its chemical forms.
Most studies indicate that total Zn concentration
increased in sludge-treated soils. Some authors reported
that Zn was mainly found in the residual and in the
organically bound fractions (Canet et al., 1997; Luo and
Christie, 1998; Illera et al., 2000). In contrast, Walter and
Cuevas (1999) reported that Zn was mainly precipitated as
carbonates in sludge-amended soils. These authors also
measured an extremely low concentration of Zn in the
exchangeable (EXCH) fraction, due to the high pH of this
soil, in agreement with the results obtained by Illera et al.
(2000) and Chaudhuri et al. (2003). Other studies reported
the increases in exchangeable Zn and/or Zn adsorbed by
Fe–Mn oxides (Hseu et al., 2006). These different results
are due to the fact that the speciation of Zn in SS-amended
soils depends on its initial chemical state in the sewage, on
soil characteristics and on the adsorption and precipitation
mechanisms that occur when sludge is land applied
(Petruzzelli et al., 1994). Sludge processing methods also
affect PTE availability and mobility (Richards et al., 2000).
The purpose of this study was to determine the chemical
fractions of Zn in three representative soil types of the
Pampas Region, Argentina, after the addition of non-
digested SS or a mixture of SS plus SS AS, and to study
how this fractions changed over a period of one year.
2. Materials and methods
2.1. Soils, sewage sludge and sewage–ash mixture
characterization
This study selected three surface soils (0–15 cm)
to represent three representative Mollisols (U.S. Soil
Taxonomy) of the Pampas Region, Argentina. The soils
are classified as Typic Hapludoll, Typic Natraquoll and
Typic Argiudoll, sampled near Carlos Casares
(351370
S–611220
W), Pila (36110
S–58180
W) and San Antonio
de Areco (341150
S–591290
W) towns, respectively. The soils
had different particle size distributions, although the clay
fraction had the same origin and mineralogical composi-
tion (Soriano et al., 1991). Composed soil samples (10
subsamples, 0–15 cm depth) were taken from pristine areas
with no previous history of fertilization or contamination.
Soils were air-dried, ground, and passed through a 2-mm
sieve for physical and chemical analysis.
Non-digested SS was obtained from Aldo Bonzi waste-
water treatment plant located at the SW outskirts of
Buenos Aires City. The sludge (SS) was dried at 60 1C
before grinding and sieving (o2 mm) and then split into
two portions. One portion was incinerated at 500 1C in a
muffle furnace. The AS obtained was thoroughly mixed
with a portion of the sieved SS, resulting in a new mixed
waste which contained 30% DM as AS.
Total organic carbon content was determined by wet
oxidation (Amato, 1983), total N was measured using the
Kjeldhal method (Bremner and Keeney, 1966) and total P
was measured by employing the sodium carbonate fusion
method (Kuo, 1996). Cation exchange capacity (CEC) was
ARTICLE IN PRESS
S.I. Torri, R. Lavado / Journal of Environmental Management 88 (2008) 1571–15791572

determined with the ammonium acetate method, pH 7.0
(Rhoades, 1982). Soil particle-size distribution was deter-
mined with the pipette method (Gee and Bauder, 1986).
The pH was measured with a glass electrode using a 1:2.5
sample/water ratio. Finally, total Zn was solubilised by
acid digestion with a 2:5 mixture of hydrofluoric and nitric
acids (Shuman, 1979) and determined with a flame atomic
absorption spectrophotometer (FAAS).
2.2. Incubation experiments
Both amendments (SS and AS) were homogeneously
mixed with each of the three air-dried soils to achieve
application rates of 62 g kg–1
to simulate 150 Mg haÀ1
in
the field. Sludge loading rates were, by design, much higher
than agronomic use would dictate over the time frame of
the experiment. These loadings were used to build high soil
Zn contents in order to assess the potential impact of long-
term SS application. Each soil-amendment mixture of
106.25 g were poured into pots which had drainage holes to
keep aeration conditions; a control with no sludge was also
included for each soil. The experiment consisted of a
factorial design of 3 Â 3 with 108 pots (3 soils Â 3
treatments Â 3 replications Â 4 sampling dates). The potted
samples were arranged in completely randomised blocks
and incubated at ambient temperature in the greenhouse.
Soil moisture content was maintained at 75% of field soil
capacity by distilled water (Cook and Millar, 1946). Three
pots for each treatment were sampled on days 1, 60, 270
and 360, air-dried and passed through a 2-mm plastic sieve
for analysis.
2.3. Sequential extractions
Concentration of Zn in pristine or incubated soil was
determined by the sequential chemical extraction proce-
dure described by McGrath and Cegarra (1992), which in
turn was a modified version of the one used by Sims and
Kline (1991) for sludge-amended soils. This type of
sequential extraction has been successfully used for
sludge-treated soils (Walter and Cuevas, 1999; Alva et al.,
2000; Chaudhuri et al., 2003; Amir et al., 2005, among
others).
Sieved soil of 3 g (70.001) was subjected to the
sequential chemical extraction procedure using 50 cm3
polypropylene centrifuge tubes to minimize losses of solid
material. Each of the chemical fractions was operationally
defined as follows:
(i) water-soluble and exchangeable fraction (EXCH): the
samples were shaken at room temperature with 30 cm3
of 0.1 M CaCl2 (v1) for 16 h, and centrifuged at
3600 rpm for 45 min. The weight of the tube and its
contents were recorded and the supernatant was
decanted and filtered through Whatman No. 42 filter
paper. The weight of the wet residue in the tube was
also recorded.
(ii) OM-bound fraction: the residue from (i) was shaken at
room temperature with 30 cm3
of 0.5 M NaOH (v2) for
16 h, centrifuged as before, filtered and the weight was
recorded as described above. Because this reagent also
extracted OM, the supernatant was digested in aqua
regia.
(iii) inorganic fraction (INOR): 30 cm3
of 0.05 M Na2ED-
TA (v3) was added to the residue of (ii) and was shaken
for 1 h, centrifuged, filtered and the weight was
recorded as described in (i). This step extracts mainly
from carbonate forms, and/or Zn associated with Fe
and Mn oxides.
(iv) residual fraction (RES).
The weights (in g) of the wet residues (minus 3 g sample)
were assumed to be equal to the volume of extractant
remaining (r) in the residue after decanting the super-
natant, and were used to correct Zn concentration in the
subsequent extracts. The following formulas were used to
calculate the amount of Zn (in mg kgÀ1
) in each of the
above extracts:
(i) c1 v1,
(ii) c2 (v2+r1)Àc1 r1,
(iii) c3 (v3+r2)Àc2 r2,
where cn is the concentration (mg cmÀ3
) in sequential
extract n; vn the volume (cm3
) of supernatant n; rn the
volume (cm3
) of extract entrained in the pellet from
extract n.
Total Zn concentration in the whole soil sample and in
the residual fraction was determined after acid digestion
with a mixture of concentrated HNO3, HCl, HF (Shuman,
1979) by FAAS. Three replicated samples were measured
in all cases. Blanks were used for background concentra-
tions. All analyses were checked against standard reference
materials from NIST. The differences between total Zn
content estimated by summation of the four fractions and
the total content obtained by acid digestion of the samples
were, in all cases, less than 10%.
2.4. Statistical analysis
Data were analyzed using analysis of variance for a
completely randomised design. Means were compared
using Tuckey’s test (Statistics 7.0, 2000). Statistical
significance was defined as po0.05. Linear correlation
was used to compare the concentration of Zn fractions and
soil characteristics.
3. Results and discussion
3.1. Characteristics of pristine soils, sewage sludge and
sewage–ash mixture
Soil characteristics are representative of the region
(Table 1). Soils in the Pampas region are moderately acid,
ARTICLE IN PRESS
S.I. Torri, R. Lavado / Journal of Environmental Management 88 (2008) 1571–1579 1573

low in available P, and have high organic carbon content
(29–46 g kgÀ1
). The region shows no signs of contamina-
tion with PTE, with concentrations and dispersion values
of PTE similar to other non-contaminated soils of the
world (Lavado, 2006). The pH values of the soils, SS and
SS–AS mixture were below 6.5.
Total Zn concentration in pristine soil samples were
within the values determined by Lavado (2006, Table 1).
The distribution of Zn in pristine soil fractions are shown
in Figs. 1–4. Native Zn was mainly found as RES-Zn,
exceeding 84% of the total content. The order of Zn
concentration in the fractions of the three pristine soils
was: RES-Zn4INOR-Zn4OM-Zn4EXCH-Zn. This re-
sult is typical for Zn found in non-contaminated soils
(Shuman, 1999) where it is mostly found in unreactive
forms in the crystal lattices of the minerals.
Sequential chemical fractionation of Zn in SS and AS
samples is shown in Table 2. In SS, Zn was predominantly
in the inorganic and residual fraction. Incineration reduced
the percentage of Zn extracted in the first two fractions
(EXCH+OM) and increased Zn in the residual fraction,
which agrees with the results reported by Obrador et al.
(2001). This increase in the residual fraction may indicate
that the element was occluded in secondary minerals
during incineration. Likewise, Zevenbergen et al. (1994)
indicated that most PTE exist as a solid solution in
combustion residues. Between 14.7% and 21.9% of Zn was
recovered as OM-Zn in SS or AS, a higher percentage than
other studies (Amir et al., 2005; Obrador et al., 2001),
whereas relatively low amounts of Zn were found in the
water-soluble and exchangeable fraction.
3.2. Changes in chemical speciation of Zn with time
Zn distribution among the studied fractions did not
change throughout the experimental period (po0.05) in the
control treatments. The application of SS and AS
significantly increased EXCH-Zn, OM-Zn and INOR-Zn
in all soils at each sampling date.
3.2.1. Changes in the water-soluble and exchangeable
fraction
A general increase in EXCH-Zn over incubation time
was observed in all sludge-treated soils (Fig. 1). The
magnitude of the increase varied according to the soil. For
day 1, EXCH-Zn was significantly higher in SS than in AS
treatment for all soils. However, between days 60 and 360,
no significant differences in EXCH-Zn were observed
comparing SS and AS treatments for the same soil. These
results indicate that Zn incorporated into the soils as a
mixture of SS and AS did not increase the most available
fraction of Zn compared to the pure SS treatment in all
sampling dates. Conversely, other studies reported in-
creases in bioavailability of Zn in soils amended with
sludge AS (Bierman and Rosen, 1994; Saikia et al., 2006).
Oxidizing conditions such as incineration are postulated to
change organic Zn into oxides (Chang et al., 1999), which
may furthermore form chloride compounds (Belevi and
Moench, 2000), increasing Zn bioavailability in AS-
amended soils. Xiao et al. (1999) also reported that AS/
sludge mixtures have elevated concentration of dissolved
OM that increased PTE bioavailability. However, in this
study, at day 1 the amounts of EXCH-Zn in the AS
treatment were significantly lower than in the SS treatment.
With regard to the effect of time, the significant increase
of EXCH-Zn in all sludge-treated soils (Fig. 1) is partially
due to the mineralization of sludge OM. This is consistent
with several other studies (McGrath et al., 2000; Nyaman-
gara, 1998). However, after day 60, the concentration of
EXCH-Zn depended on soil characteristics. Soil particle
size distribution and soil pH are usually considered to play
important roles in controlling trace metal availability. In
ARTICLE IN PRESS
Table 1
Selected properties of the soils (Typic Hapludoll, Typic Natraquoll and Typic Argiudoll), pure sewage sludge (SS) and the 70:30, w/w mixture of sewage
sludge and sludge ash (AS)
Typic Hapludoll Typic Natraquoll Typic Argiudoll SS AS
Clay (%) 19.2 27.6 32.7
Silt (%) 23.2 43.0 57.5
PH 5.12 6.21 5.44 5.82 6.17
Organic carbon (g kgÀ1
) 28.6 35.31 23.9 251 176
Total N (mg gÀ1
) 2.62 3.6 2.5 19.3 21.3
Total P (mg gÀ1
) 1.07 1.09 1.46 7.2 8.6
EC (dS mÀ1
)a
0.61 1.18 0.90 0.9 0.89
CEC (cmol(c) kgÀ1
)b
22.3 22.3 15.3 11.95
Total Zn (mg kgÀ1
) 55 47 59 2500 3150
Exchangeable cations
Ca2+
(cmol(c) kgÀ1
) 5.2 9.1 11.0
Mg2+
(cmol(c) kgÀ1
) 2.0 5.4 1.8
Na+
(cmol(c) kgÀ1
) 0.3 3.1 0.1
K+
(cmol(c) kgÀ1
) 2.8 1.6 2.2
a
Electrical conductivity.
b
Cation exchange capacity.

this study, the concentration of EXCH-Zn was not related
to clay content. The pH of the amended soils was
significantly higher than controls in all sampling dates
(data not shown). With time, a decrease in pH in sludge-
treated soils was observed associated with a concomitant
increase in EXCH-Zn. It was concluded that soil pH
strongly affected the concentration of EXCH-Zn in all
sampling dates in the amended soils (r ¼ 0.94). Similar
results were found in other studies (Basta and Sloan, 1999).
3.2.2. Changes in the organic matter bound fraction
OM-Zn was significantly higher for the SS treatment
compared to the AS treatment at day 1 (Fig. 2), but no
significant differences were observed after day 60 between
both treatments for each soil. The intense mineralization of
the labile OM pool of sludge treated-soils (Torri et al.,
2003) resulted in a decrease in OM-Zn after day 60. The Zn
released increased EXCH-Zn as well as the inorganic
fraction of the amended soils, in agreement with other
studies (Shuman, 1999; Xiao et al., 1999). It is well known
that pH influences metal solubility by controlling the extent
of metal-complexation with organic C-based ligands. Sims
and Kline (1991) reported that acidity reduced the
ARTICLE IN PRESS
EXCH-Zn, day 1
c
b
a
c
b
a
c
b
a
0
20
40
60
Controll SS treatment AS treatment
EXCH-Zn(mgkg-1)
Typic Hapludoll
Typic Natraquoll
Typic Argiudoll
EXCH-Zn, day 60
c
a a
c
b
b
c
a a
0
20
40
60
Control SS treatment AS treatment
EXCH-Zn(mgkg-1)
EXCH-Zn, day 270
a
a
d
cc
e
b
ab
e
0
20
40
60
EXCH-Zn(mgkg-1)
EXCH-Zn, day 360
a
a
d
c
bc
e
b
a
e
0
20
40
60
EXCH-Zn(mgkg-1)
Fig. 1. Distribution of exchangeable Zn in the Typic Hapludoll, Typic
Natraquoll and Typic Argiudoll amended with pure sludge (SS), and the
70:30 (w/w) mixture of sewage sludge and sludge ash (AS). For each date,
different letters indicate significant differences (Tuckey, po0.05).
OM-Zn, day 1
c
b
a
c
b
a
c
a
b
0
20
40
60
0
20
40
60
0
20
40
60
0
20
40
60
OM-Zn(mgkg-1)
Typic Hapludoll
Typic Natraquoll
Typic Argiudoll
OM-Zn, day 60
abab
c
a
ab
c
ab
b
c
OM-Zn(mgkg-1) OM-Zn, day 270
aa
d
abb
d
bc
c
d
OM-Zn(mgkg-1)
OM-Zn, day 360
a
bc
d
abab
d
bc
c
d
OM-Zn(mgkg-1)
Fig. 2. Distribution of organic Zn in the Typic Hapludoll, Typic

percentage of OM-Zn in soils. This was not our case, for an
increase in OM-Zn at day 360 was observed in sludge-
treated soils despite the decrease of soil pH with time.
Shuman (1999) reported that some organic waste materials,
such as spent mushroom compost and humic acid, lowered
the potential availability of Zn by redistributing it from the
exchangeable to the less soluble fractions like manganese
oxide or OM fractions. We conclude that the transforma-
tion of raw OM to stable humic substances with time
favoured the complexation of sludge-borne Zn onto stable
organic forms regardless soil pH. Moreover, the impor-
tance of pH in controlling the solubility and retention of
Zn by soils has been investigated continuously without
reaching a deﬁnitive understanding of its effect on
retention mechanisms in the presence of organic C found
in waste materials (Mun˜ oz-Mele´ ndez et al., 2000).
3.2.3. Changes in the inorganic fraction
Application of sludge to soils resulted in an initial
increase in the inorganic fraction (Fig. 3). INOR-Zn
increased in both sludge treatments till the end of the
ARTICLE IN PRESS
INOR-Zn, day 1
aa
b b
aa
b
aa
0
50
100
150
200
INOR-Zn(mgkg-1)
0
50
100
150
200
INOR-Zn(mgkg-1)
0
50
100
150
200
INOR-Zn(mgkg-1)
0
50
100
150
200
INOR-Zn(mgkg-1)
Typic Hapludoll
Typic Natraquoll
Typic Argiudoll
INOR-Zn, day 60
ab
b
c
aa
c
ab
ab
c
INOR-Zn, day 270
ab
bc
e
a
abc
de
abc
c
d
INOR-Zn, day 360
abc
c
e
a
ab
de
ab
bc
d
Fig. 3. Distribution of inorganic Zn in the Typic Hapludoll, Typic
RES-Zn, day 1
e
c
a
f
d
b
e
c
a
0
50
100
150
200
RES-Zn(mgkg-1) 0
50
100
150
200
RES-Zn(mgkg-1)
Typic Hapludoll Typic Natraquoll Typic Argiudoll
RES-Zn, day 60
bc
a
a
c
bc
ab
bc
a
a
RES-Zn, day 270
abc
bcbc
abcabc
c
a
ab
bc
0
50
100
150
200
RES-Zn(mgkg-1)
RES-Zn, day 360
abc
ab
ab
bcc
ab
a
ab
ab
0
50
100
150
200
RES-Zn(mgkg-1)
Fig. 4. Distribution of residual Zn in the Typic Hapludoll, Typic

studied period, representing from day 60 the most
abundant fraction for the Natraquoll, from day 270 for
the Hapludoll and at day 360 for the Argiudoll. INOR-Zn
showed no significant differences between SS and AS
treatments for each amended soil during the studied
period. At day 360, this fraction accounted between 41%
and 76% of total Zn content in the amended soils, in good
agreement with other reports (Qiao et al., 2003; Walter and
Cuevas, 1999). Zn has a relatively high affinity for sorption
on the surfaces of Fe/Mn/Al-hydroxides (Meima and
Comans, 1999), which are usually present in large amounts
in municipal solid waste incinerator AS (Stipp et al., 2002).
These processes are enhanced by increasing soil pH
(Alloway and Jackson, 1991; Luo and Christie, 1998;
Morera et al., 2002). This fact may explain why INOR-Zn
was the largest fraction firstly present in the Natraquoll
compared to the other two soils. Although the shift of Zn
towards the inorganic fraction was regulated by soil pH,
correlation coefficients between INOR-Zn and soil pH
were significant at p ¼ 0.001 (r ¼ 0.92) only at day 360. So,
with the passage of time, Zn was combined in forms of low
availability through slow precipitation reactions or sorp-
tion onto Fe/Mn/Al-hydroxides or neoformed clay-like
minerals, enhanced by increasing soil pH.
3.2.4. Changes in the residual fraction
RES-Zn was the most abundant fraction in the amended
soils at the beginning of the incubation (Fig. 4). At day 1,
incineration significantly increased the concentration of Zn
extracted in the residual fraction, corresponding to 60% of
total Zn in the AS treatment compared to 50% in the SS
treatment. However, Zn in the residual fraction gradually
decreased for both sludge treatments over time until, at day
360, this fraction was not statistically different from
controls in the three amended soils.
PTE associated with the residual fraction are usually
considered as if they could not be released (Legret et al.,
1993). However, SS AS is predominantly composed of
high-temperature solids. In a natural atmospheric environ-
ment, many of these solids are metastable and alter to form
thermodynamically stable assemblages of minerals (Meima
et al., 2002; Chandler et al., 1997). The results obtained in
this study indicate that similar reactions may occur in
sludge-amended soils. Thus, weathering decreased the
proportion of Zn in the residual fraction as indicated by
the decrease of the proportion of Zn in SS- or AS-amended
soils, with a concomitant increase in the inorganic fraction.
4. Conclusion
The use of a mixture of AS and SS as a soil amendment
did not show significant differences in Zn concentration in
water-soluble and exchangeable, organic and inorganic
fraction in the Typic Hapludoll, Typic Natraquoll and
Typic Argiudoll compared to pure SS over a one-year
period.
A dynamic equilibrium of Zn forms in soils was
observed. The increase of water-soluble and exchangeable
Zn with time in both sludge-treated soils indicate that these
amendments are an important short-term source of
relatively mobile and available forms of Zn. A negative
and significant correlation between exchangeable Zn and
soil pH was found.
At day 1, Zn was mainly found in the residual fraction in
both sludge-treated soils. A redistribution towards the
inorganic fraction was observed, representing the most
abundant fraction in the three soils a year after sludge
application. At the end of the year, inorganic Zn was
positively and significantly correlated with soil pH.
Based on these results, land spreading of SS with its own
AS may be similar to SS disposal in terms of Zn mobility.
Nevertheless, long-term availability of Zn following the
application of these amendment requires further studies.
References
Alloway, B., 1990. Soil processes and the behaviour of metals. In:
Alloway, B.J. (Ed.), Heavy Metals in Soils. Blackie Academic and
Professional, Glasgow, pp. 7–28.
Alloway, B., Jackson, A.P., 1991. The behavior of heavy metals in sludge
amended soils. Science of the Total Environment 100, 151–176.
Alva, A.K., Huang, B., Paramasivam, S., 2000. Soil pH affects copper
fractionation and phytotoxicity. Soil Science Society of America
Journal 64, 955–962.
Amato, M., 1983. Determination of 12
C and 14
C in plant and soil. Soil
Biology & Biochemistry 15, 611–612.
Amir, S., Hafidi, M., Merlina, G., Revel, J.C., 2005. Sequential extraction
of heavy metals during composting of sewage sludge. Chemosphere 59,
801–810.
Anguissola Scotti, I., Silva, S., Baffi, C., 1999. Effects of fly ash pH on the
uptake of heavy metals by chicory. Water, Air and Soil Pollution 109,
397–406.
Basta, N.T., Sloan, J.J., 1999. Bioavailability of heavy metals in strongly
acidic soils treated with exceptional quality biosolids. Journal of
Environmental Quality 28, 633–638.
Belevi, H., Moench, H., 2000. Factors determining the element behavior in
municipal solid waste incinerators. 2. Laboratory experiments.
Environmental Science & Technology 34, 2507–2512.
Bierman, P.M., Rosen, C.J., 1994. Phosphate and trace metal availability
from sewage-sludge incinerator ash. Journal of Environmental Quality
23, 822–830.
Bremner, J.M., Keeney, D.R., 1966. Determination and isotope-ratio
analysis of different forms of nitrogen in soils: 3. Exchangeable
‘ammonium, nitrate, and nitrite’ by extraction distillation methods.
Soil Science Society of America Proceedings 30, 577–582.
ARTICLE IN PRESS
Table 2
Distribution of Zn (media7SE, n ¼ 3) among water-soluble and
exchangeable fraction (EXCH), organic matter bound fraction (OM),
inorganic precipitate fraction (INOR) and residual fraction (RES) in
sewage sludge (SS) and in the 70:30 (w/w) mixture of sewage sludge and
sludge ash (AS)
SS (mg kgÀ1
) AS (mg kgÀ1
)
EXCH-Zn 233.179.2 160.07714.3
OM-Zn 548.576.4 399.879.7
INOR-Zn 888.8718.9 861.2710.6
RES-Zn 830.2712.5 1292.3710.1

Canet, R., Pomares, F., Tarazona, F., 1997. Chemical extractability
and availability of heavy metals after seven year application of
organic wastes to a citrus soil. Soil Use and Management 13,
117–121.
Chandler, A.J., Eighmy, T.T., Hartle´ n, J., Hjelmar, O., Kosson, D.S.,
Sawell, S.E., van der Sloot, H.A., Vehlow, J., 1997. Municipal solid
waste incinerator residues. Studies in Environmental Science, vol. 67.
Elsevier, Amsterdam.
Chaney, R.L., 1993. Zn phytotoxicity. In: Robson, A.D. (Ed.), Zinc
in Soils and Plants. Kluwer Academic Publishers, Dordrecht,
pp. 135–150.
Chang, Y.M., Chang, T.C., Lin, J.P., 1999. Effect of incineration
temperature on lead emission from a fixed bed incinerator. Journal
of Chemical Engineering of Japan 32, 626–634.
Chaudhuri, D., Tripathy, S., Veeresh, H., Powell, M.A., Hart, B.R., 2003.
Mobility and bioavailability of selected heavy metals in coal ash- and
sewage sludge-amended acid soil. Environmental Geology 44 (4),
419–432.
Cook, R.L., Millar, C.E., 1946. Some techniques which help to make
greenhouse investigation comparable with field plot experiments. Soil
Science Society of America Proceedings 11, 298–304.
Corey, R.B., King, L.B., Lue-Hing, C., Fanning, D.S., Street, J.J.,
Walfer, J.M., 1987. Effects of sludge properties on accumulation of
trace elements by crops. In: Page, A.L., Logan, T.J., Ryan, J.A. (Eds.),
Land Application of Sludge-food Chain Implications. Lewis Publish-
ers Inc., Chelsea, MI, pp. 25–51.
Gee, G.W., Bauder, J.W., 1986. Particle-size analysis. In: Klute, A. (Ed.),
Methods of Soil Analysis, Part 1, second ed., Agronomy Monograph
vol. 9, Agronomy Society of America and Soil Science Society of
America, Madison, pp. 383–412.
Hesterberg, D., 1998. Biogeochemical cycles and processes leading to
changes in mobility of chemicals in soils. Agriculture, Ecosystems &
Environment 67, 121–133.
Hseu, Z.Y., 2006. Extractability and bioavailability of zinc over time in
three tropical soils incubated with biosolids. Chemosphere 63,
762–771.
Illera, V., Walter, I., Souza, P., Cala, V., 2000. Short-term effects of
biosolid and municipal solid waste applications on heavy metals
distribution in a degraded soil under a semi-arid environment. Science
of the Total Environment 255, 29–44.
Khan, J., Qasim, M., Umar, M., 2006. Utilization of sewage sludge as
organic fertiliser in sustainable agriculture. Journal of Applied Science
6, 531–535.
Kuo, S., 1996. Phosphorus. In: Sparks, D.L. (Ed.), Methods of Soil
Analysis, Part 3, SSSA Book Series no. 5. Agronomy Society of
America and Soil Science Society of America, Madison, pp. 869–919.
Lavado, R., 2006. Concentration of potentially toxic elements in field
crops grown near and far from cities of the Pampas (Argentina).
Journal of Environment Management 80, 116–119.
Legret, M., Colandini, V., Raimbault, G., 1993. Premie` re approche des
effects des structures re` servoirs sur la qualite` des eaux pluviales et des
sols. La Houille Blanche, 201–205.
Luo, Y.M., Christie, P., 1998. Bioavailability of copper and zinc in soils
treated with alkaline stabilized sewage sludges. Journal of Environ-
mental Quality 27, 335–342.
McBride, M.B., Richards, B., Steenhuis, T., Russo, J., Sauve´ , S., 1997.
Mobility and solubility of toxic metals and nutrients in soil fifteen
years after sludge application. Soil Science 162, 487–500.
McGrath, S.P., Cegarra, J., 1992. Chemical extractability of heavy metals
during and after long-term applications of sewadge sludge to soil.
Journal of Soil Science 43, 313–321.
McGrath, S.P., Zhao, F.J., Dunham, S.J., Crosland, A.R., Coleman, K.,
2000. Long-term changes in the extractability and bioavailability of Zn
and Cd after sludge application. Journal of Environmental Quality 29,
875–883.
Meers, E., Unamuno, V.R., Du Laing, G., Vangronsveld, J., Vanbroe-
khoven, K., Samson, R., Diels, L., Geebelen, W., Ruttens, A.,
Vandegehuchte, M., Tack, F.M.G., 2006. Zn in the soil solution of
unpolluted and polluted soils as affected by soil characteristics.
Geoderma 136, 107–119.
Meima, J.A., van der Weijden, R.D., Eighmy, T., Comans, R., 2002.
Carbonation processes in municipal solid waste incinerator bottom ash
and their effect on the leaching of copper and molybdenum. Applied
Geochemistry 17, 1503–1513.
Moreno, J.L., Garcia, C., Hernandez, T., Ayuso, M., 1997. Application
of composted sewage sludges contaminated with heavy metals
to an agricultural soil. Soil Science and Plant Nutrition 43,
565–573.
Morera, M., Echeverrıá, J., Garrido, J., 2002. Bioavailability of heavy
metals in soils amended with sewage sludge. Canadian Journal of Soil
Science 81, 405–414.
Mun˜ oz-Mele´ ndez, G., Korre, A., Parry, S.J., 2000. Influence of soil pH on
the fractionation of Cr, Cu and Zn in solid phases from a landfill site.
Environmental Pollution 110, 497–504.
Nyamangara, J., 1998. Use of sequential extraction to evaluate zinc and
copper in a soil amended with sewage sludge and inorganic metal salts.
Agriculture, Ecosystems & Environment 69, 135–141.
Obrador, A., Rico, M.I., Alvarez, J.M., Novillo, J., 2001. Influence of
thermal treatment on sequential extraction and leaching behaviour of
trace metals in a contaminated sewage sludge. Bioresource Technology
76, 259–264.
Obrador, A., Novillo, J., Alvarez, J.M., 2003. Mobility and availability to
plants of two zinc sources applied to a calcareous soil. Soil Science
Society of America Journal 67, 564–572.
Paramasivam, S., Sajwan, K.S., Alva, A.K., VanClief, D., Hostler, K.H.,
2003. Elemental transport and distribution in soils amended with
incinerated sewage sludge. Journal of Environmental Science and
Health A 38, 807–821.
Paramasivam, S., Sajwan, K.S., Alva, A.K., 2006. Incinerated sewage
sludge products as amendments for agricultural soils: Leaching and
plant uptake of trace elements. Water, Air and Soil Pollution 171,
273–290.
Qiao, X.L., Luo, Y.M., Christie, P., Wong, M.H., 2003. Chemical
speciation and extractability of Zn, Cu and Cd in two contrasting
biosolids-amended clay soils. Chemosphere 50, 823–829.
Rhoades, J.D., 1982. Cation exchange capacity, in: Page, A.L., Miller, R.H.,
Keeney, D.R. (Eds.), Methods of Soil Analysis, Part 2, second ed.,
Agronomy Monograph vol. 9, Agronomy Society of America and Soil
Science Society of America, Madison, pp. 149–157.
Richards, B.K., Steenhuis, T.S., Peverly, J.H., McBride, M.B., 2000.
Effect of sludge-processing mode, soil texture and soil pH on metal
mobility in undisturbed soil columns under accelerated loading.
Environmental Pollution 109, 327–346.
Rodriguez, M., Lavado, R., 2004. Uptake and distribution of trace
elements by soybean from a physically degraded soil treated with
biosolids. Agrochimica 48, 1–2.
Saikia, N., Kato, S., Kojima, T., 2006. Compositions and leaching
behaviours of combustion residues. Fuel 85, 264–271.
Shuman, L.M., 1979. Zinc, manganese and copper in soil fractions. Soil
Science 127, 10–17.
Shuman, L.M., 1999. Organic waste amendments effect on zinc
fractions of two soils. Journal of Environmental Quality 28,
1442–1447.
Sims, J.T., Kline, J.S., 1991. Chemical fractionation and plant uptake of
heavy metals in soils amended with co-composed sewage sludge.
Journal of Environmental Quality 20, 387–395.
Soriano, A., Leo´ n, R.J.C., Sala, O.E., Lavado, R.S., Deregibus, V.A.,
Cauhe´ pe´ , M.A., Scaglia, O.A., Vela´ zquez, C.A., Lemcoff, J.H., 1991.
Rio de la Plata grasslands. In: Coupland, R.T. (Ed.), Temperate
Subhumid Grasslands. Ecosystems of the World. Vol. 8, Natural
Grasslands. Elsevier Scientific Publishing Co, Amsterdam, pp.
367–407.
Stipp, S., Hansen, M., Kristensen, R., Hochell, M., Bennedsen, L.,
Dideriksen, K., Balic-Zunic, T., Le´ onard, D., Mathieu, H., 2002.
Behaviour of Fe-oxides relevant to contaminant uptake in the
environment. Chemical Geology 190, 321–337.
ARTICLE IN PRESS

Teruggi, M., 1957. The nature and origin of Argentinean loess. Journal of
Sedimentology and Petrology 27, 322–332.
Torri, S., Alvarez, R., Lavado, R., 2003. Mineralization of Carbon from
Sewage sludge in three soils of the Argentine pampas. Communica-
tions in Soil Science and Plant Analysis 34, 2035–2043.
Urricariet, S., Lavado, R.S., 1999. Indicadores de deterioro en suelos de la
Pampa Ondulada. Ciencia del Suelo 17, 37–42.
Vijver, M., Jager, T., Posthuma, L., Peijnenburg, W., 2003. Metal uptake
from soils and soil–sediment mixtures by larvae of Tenebrio molitor
(L.) (Coleoptera). Ecotoxicology and Environmental Safety 54,
277–289.
Walter, I., Cuevas, G., 1999. Chemical fractionation of heay metals in a
soil amended with repeated sewage sludge application. Science of the
Total Environment, 113–119.
Winder, L., Merrington, G., Green, I., 1999. The tri-trophic transfer of Zn
from the agricultural use of sewage sludge. Science of the Total
Xiao, C., Ma, L.Q., Sarigumba, T., 1999. Effects of soil on trace metal
leachability from papermill ashes and sludge. Journal of Environ-
mental Quality 25, 321–333.
Zevenbergen, C., Vander, W.T., Bradley, J.P., van der Broeck, P.,
Orbons, A.J., Van Reeuwijk, L.P., 1994. Morphological and chemical
properties of MSWI bottom ash with respect to the glassy constituents.
Hazardous Waste & Hazardous Materials 11, 371–383.
Zhang, F.S., Yamasaki, S., Nanzyo, M., 2002. Waste ashes for use in
agricultural production: I. Liming effect, contents of plant nutrients
and chemical characteristics of some metals. Science of the Total
ARTICLE IN PRESS

Zn distribution in soils amended with different kinds of sewage sludge

Recommended

Recommended

More Related Content

What's hot

What's hot (19)

Similar to Zn distribution in soils amended with different kinds of sewage sludge

Similar to Zn distribution in soils amended with different kinds of sewage sludge (20)

More from Silvana Torri

More from Silvana Torri (20)

Recently uploaded

Recently uploaded (20)

Zn distribution in soils amended with different kinds of sewage sludge