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The role of leaching and geochemical modelling in the assessment of coal fly ash and sewage sludge use in agriculture
Hans A. van der Sloot and David S. Kosson
NC
AB
Work
shop
May 2
9,
2014, Tel A
viv
Overview of presentation
01/06/2014 2
- Total content versus leachability
- Standardised leaching tests
- Soil leaching data
- Geochemical speciation modelling
- Mixture modelling
- Conclusions and Recommendations
- When of interest, ecotoxicity versus leaching
Questions to be answered in relation to contaminated soil and agricultural soil
- Does a given soil or agricultural soil show elevated concentration levels and, if yes, does it pose an health or an environmental risk?
- What treatment of an agricultural soil is suitable and how to judge that?
- When a treatment process has been selected, how can its preformance be verified in a practical manner?
- What are the consequences of prolonged fertilizer use or application of soil amendment on soil quality?
- How can a soil be judged beforehand on its capacity to sustain certain uses?
- To what extent are local circumstances relevant? What are key release controlling factors?
Judgment of environmental impact on total composition or on leaching?
Relevance of different methods for total composition for environmental judgement questionable. Leaching by far more relevant for environmental impact assessment
Contaminated harbour sediment (Rhine)
0.01
0.1
1
10
100
1 3 5 7 9 11 13
pH
Le
ach
ed
(m
g/k
g)
Ni
" To ta l"
0
10
20
30
40
50
60
70
80
1 3 5 7 9 11 13
pH
Le
ach
ed
(m
g/k
g)
Pr En 1 4 4 2 9
Pr EN 1 4 4 2 9
EN 1 2 4 5 7 - 2
C a C l2
S C E
Ni
To ta l ( H F , H C lO 4 )
To ta l ( H N O 3 , H C lO 4 )
To ta l ( H N O 3 ,te f lo n b o m b )
To ta l ( A q u a R e g ia )
Log-scale Linear-scale
Relevant
pH domain
Judgment on total composition or leaching
The answer is that none of the questions posed in relation to soil contamination or agricultural issues can be solved by a judgment on the basis of total composition!!
However, that is the regulatory approach today and the sooner it is complemented or replaced by a judgement based on leachability, the more realistic the decisions in terms of true environmental impact and health will become.
MASS TRANSPORT LEACH TEST
MONOLITH PrEN 15863 or
EPA Method 1315
COMPACTED GRANULAR NEN 7347 or
EPA Method 1315
PERCOLATION LEACHING TEST
PrEN 14405 or EPA Method 1314
GRANULAR MATERIALS
MONOLITHIC MATERIALS
or
pH DEPENDENCE TEST
BATCH MODE - ANC, PrEN 14429, or EPA Method 1313
COMPUTER CONTROLLED - PrEN 14997
Chemical speciation aspects Time dependent aspects of release
Same as granular +
Standardisation: CEN/TC292, ISO/TC190, CEN/TC345, CEN/TC351, SW846 (US EPA)
Characterisation leaching tests
Test set covers most practical conditions for wide range of materials
01/06/2014 6
0.01
0.1
1
10
100
1000
1 3 5 7 9 11 13
pH
Lea
ch
ed
at
L/S
=1
0 (
mg
/kg
)
Cd
INGESTION
INHALATION
CEMENT STABILIZATION OF
CONTAMINATED SOIL
NATURAL SOIL
ACIDIC
ENVIRONMENTS
SOIL
LIMING
Test conditions related to different exposure conditions
Relevant pH domains for assessing different questions in relation to different types of impact
Heavily Sewage Sludge Amended
Soil
Total
01/06/2014 7
Comparison of soil and sediment leaching data with regulatory criteria – Inert EU Landfill criteria
Data from pH dependence and percolation is complementary. In this case, Cu proves
not to be critical in most cases (percolation), except for a very acidic, highly
contaminated soil. Based on pH dependence two more soils could be problematic.
LeachXS
EU LFD Inert
DTL
pH dependent emission of Cu
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
0 2 4 6 8 10 12 14
pH
Em
issio
n (
mg
/kg
)
SOIL-A_AUSTRIA SOIL-B_AUSTRIA
EUROSOIL4+3%compost SPAIN-Harbour sediment
River sediment Harbour NL Eurosoil4
SOIL-WP2 HORIZONTAL SEDIMENT_VENICE
Zinc Contaminated Soil EULFD, Inert
Cumulative release of Cu
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
0.1 1 10
L/S (l/kg)
Cu
mu
lati
ve r
ele
ase (
mg
/kg
)
ESOIL4 ESOIL6 ACIDIC CONT. SOIL
Zinc cont. Soil SOIL-A_AUSTRIA EULFD, Inert
slope=1.0
Comparison of soil leaching for Cu and Cr
SOIL A, SOIL B & CSO: INDUSTRIALLY CONTAMINATED SOILS
SO 1 & SO 2: NATURAL SOILS (Uncontaminated Euro Soils)
CSO 1 & CSO 2: SEWAGE SLUDGE AMENDED SOILS (Moderate, Heavy; ISPRA)
0.01
0.1
1
10
100
1000
2 4 6 8 10 12
Lea
ched
at
L/S
=1
0 (
mg
/kg
)
pH
Soil A Soil B EU SO1
EU SO2 EU CSO1 EU CSO2
COS SRM483 SRM484
Cu
(Contaminated) Soil
0.001
0.01
0.1
1
10
100
2 4 6 8 10 12
Lea
ched
at
L/S
=1
0 (
mg
/kg
)
pH
Soil A Soil B EU SO1
EU SO2 EU CSO1 EU CSO2
COS SRM483 SRM484
Cr
(Contaminated) Soil
01/06/2014 10
Geochemical Speciation modeling can:
• Provide insights into distribution of constituents within and between solid and liquid phases that controls leachability and bioavailability/toxicity.
• Explore liquid-solid partitioning at conditions beyond laboratory test conditions
• Liquid-solid ratio, redox conditions
• Composition changes (increased clay, iron, DOC, carbonation, constituents of concern, etc.)
• Provide scenario-based evaluation of management options
• Effects of physical form (monolith, granular), preferential flow, infiltration patterns & chemistry, material interfaces, etc.
• Guide testing and evaluation of material mixtures, treatment and use
Why Use Geochemical Speciation Modeling?
Input (Chemical Speciation Fingerprint)
- Element availabilities (major minor and trace elements from pH dependence test, maximum release from 2<pH<13)
- Liquid to Solid ratio (L/S=10 mL/g)
- Redox status of material/product pH+pe = 15 (oxidised)
- Clay content (kg/kg)
- Reactive Hydrated Iron oxide surface (HFO in kg/kg)
- Reactive Solid Humic Acid (SHA in kg/kg)
- Dissolved Organic Carbon (DOC in mg/L from pH dependence test)
- Selection of potentially relevant minerals controlling solubility (Partly taken from a model run to determine saturation indices (SI) for all available minerals in the thermodynamic database)
01/06/2014 11
Example Input (Chemical Speciation Fingerprint) for a Zn contaminated soil
01/06/2014 12
Prediction case SOC DOC Zn soil + kolom2 DOC/DHA data Polynomial coeficients
Speciation session Zn soil + kolom pH [DOC] (kg/l) DHA fraction[DHA] (kg/l) C0 -4.991E+00
Material Zinc_Soil (P,1,2) 1.00 7.770E-04 0.30 2.331E-04 C1 2.526E+00
3.00 2.060E-04 0.07 1.442E-05 C2 -1.406E+00
Solved fraction DOC 0.2 4.33 3.340E-05 0.06 2.004E-06 C3 2.446E-01
Sum of pH and pe 15.00 5.41 4.000E-06 0.06 2.400E-07 C4 -1.712E-02
L/S 10.0230 l/kg 6.92 7.000E-06 0.08 5.600E-07 C5 4.234E-04
Clay 1.000E-01 kg/kg 7.84 1.400E-05 0.09 1.260E-06
HFO 1.500E-03 kg/kg 9.32 1.400E-04 0.10 1.400E-05
SHA 7.000E-02 kg/kg 10.63 4.300E-04 0.12 5.160E-05
Percolation material Zinc_Soil (C,1,1) 12.16 6.260E-04 0.15 9.390E-05
Avg L/S first perc. fractions 0.1650 l/kg 14.00 7.300E-04 0.20 1.460E-04
Reactant concentrations
Reactant mg/kg Reactant mg/kg Reactant mg/kg Reactant mg/kg
Ag+ not measured CrO4-2 3.180E+00 Mg+2 3.019E+02 SO4-2 1.083E+03
Al+3 6.348E+02 Cu+2 4.398E+03 Mn+2 9.120E+02 Sb[OH]6- 3.485E+00
H3AsO4 1.751E+01 F- 8.359E+00 MoO4-2 2.400E+00 SeO4-2 6.299E+00
H3BO3 2.204E+00 Fe+3 2.110E+03 Na+ 7.416E+01 H4SiO4 3.040E+03
Ba+2 1.657E+01 H2CO3 1.000E+04 NH4+ 1.000E+00 Sr+2 2.734E+00
Br- not measured Hg+2 not measured Ni+2 1.888E+02 Th+4 not measured
Ca+2 4.383E+02 I- not measured NO3- 5.000E+01 UO2+ not measured
Cd+2 5.399E+00 K+ 5.373E+01 PO4-3 2.066E+01 VO2+ 6.170E-01
Cl- 2.132E+01 Li+ 1.198E+00 Pb+2 1.934E+03 Zn+2 3.450E+04
Selected Minerals
Albite[low] Ca2Cd[PO4]2 FCO3Apatite Kaolinite Ni[OH]2[s] PbMoO4[c] Zn-Rockbridgite
AlOHSO4 Ca2Zn3[PO4]3OH Ferrihydrite Laumontite Ni2SiO4 Pyrophyllite
Anglesite Ca4Cd[PO4]3OH Fluorite LDH_Zn NiCO3[s] Rhodochrosite
Ba[SCr]O4[96%SO4] Calcite Forsterite Magnesite Otavite Sb[OH]3[s]
BaSrSO4[50%Ba] CaZincate Huntite Microcline Pb[OH]2[C] Strontianite
Boehmite Cd[OH]2[C] HydromagnesiteMnHPO4[C] Pb3[VO4]2 Tenorite
Brucite CuCO3[s] Illite[1] Monticellite Pb4[OH]6SO4 Zincite
Bunsenite Dioptase Illite[2] Montmorillonite PbCrO4 Zn[OH]2[A]
From pH dependence test data
ISO/TS 12782 series
Expert judgement
Model simulation L/S=10 and model prediction at L/S=0.2 for a Zn contaminated soil
01/06/2014 13
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l) [Ba+2] as function of pH
TS14429TS14405
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
[Ca+2] as function of pH
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
[Fe+3] as function of pH
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
[Mg+2] as function of pH
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
[PO4-3] as function of pH
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1 2 3 4 5 6 7 8 9 10 11 12 13 14
[Cd+2] as function of pH
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1 2 3 4 5 6 7 8 9 10 11 12 13 14
[Cu+2] as function of pH
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
[Mn+2] as function of pH
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
[Zn+2] as function of pH
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
ncen
trati
on
(m
ol/
l)
pH
[CrO4-2] as function of pH
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
[H3AsO4] as function of pH
1.0E-11
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
[MoO4-2] as function of pH
Simulation of release behaviour at L/S=10 (red lines) and at L/S=0.2 (blue lines)
red dots: pH dependence test data (red dots); percolation test data (blue dots).
Partitioning of particulate and dissolved phases for a Zn contaminated soil
01/06/2014 14
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Cu
Zinc_Soil pH dep 14229 [Cu+2] Zinc_Soil (C,1,1) [Cu+2]
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid-solid, [Cu+2]
Free DOC-bound POM-bound FeOxide Clay Tenorite
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fra
cti
on
of
tota
l co
nce
ntr
ati
on
(%
)
pH
Cu+2 fractionation in solution
Free DOC-bound
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fra
cti
on
of
tota
l co
nce
ntr
ati
on
(%
)
pH
Cu+2 fractionation in the solid phase
POM-bound FeOxide Clay Tenorite
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
As
Zinc_Soil pH dep 14229 [H3AsO4] Zinc_Soil (C,1,1) [H3AsO4]
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid-solid, [H3AsO4]
Free DOC-bound POM-bound FeOxide Clay
100%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fra
cti
on
of
tota
l co
nce
ntr
ati
on
(%
)
pH
H3AsO4 fractionation in solution
Free DOC-bound
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fra
cti
on
of
tota
l co
nce
ntr
ati
on
(%
)
pH
H3AsO4 fractionation in the solid phase
POM-bound FeOxide Clay
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Zn
Zinc_Soil pH dep 14229 [Zn+2] Zinc_Soil (C,1,1) [Zn+2]
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid-solid, [Zn+2]
Free DOC-bound POM-bound FeOxide Clay Zincite Zn-Rockbridgite
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fra
cti
on
of
tota
l co
nce
ntr
ati
on
(%
)
pH
Zn+2 fractionation in solution
Free DOC-bound
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fra
cti
on
of
tota
l co
nce
ntr
ati
on
(%
)
pH
Zn+2 fractionation in the solid phase
POM-bound FeOxide Clay Zincite Zn-Rockbridgite
Prediction leachate quality taking preferential flow into account (80% stagnant- dual porosity model)
10010000
0.01 100
L/S
Landgraaf kolomtest
Model praktijk
Availability
Model kolomtest
Cd affected by substantially reduced Cl release, other metals not influenced (solubility controlled). Cl substantially reduced by preferential flow.
01/06/2014 15
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100
L/S
Cr
(mg
/k
g)
100
1000
10000
0.01 0.1 1 10 100
L/S
Cl
(mg
/k
g)
0.01
0.1
1
10
100
1000
0.01 0.1 1 10 100
L/S
Cu
(m
g/k
g)
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100
L/S
Cd
(m
g/k
g)
Modelling of Soil – Admixtures
01/06/2014 16
In the case of soil amendment or in contaminated sites with a specific
input of contaminants, modelling of material mixtures is feasible using
existing Chemical Speciation Fingerprint (CSF) data on soil and on
the admixture.
This can be realized in different mixing ratios with verification of
suitability of prediction at selected conditions. This forms an economic
way of assessing a wide range of possible conditions in a
contaminated site.
Geochemical modelling of material mixtures (e.g. soil with industrial
residues in varying proportions) and verification by experimental
leaching work is a new means to assess contaminated sites
01/06/2014 17
Modelling of Soil – Coal fly ash – Sewage sludge mixtures
For Cd and Cr
the effect is DOC
related
(originating from
sewage sludge)
01/06/2014 18
Modelling of Soil – Coal fly ash – Sewage sludge mixtures (2)
The effect for B
(from CFA)
seems
proportional to
the addition.
However, the
observed B
behaviour in soil
is not captured -
thermodynamic
data for possible
controlling
phases missing.
For Cu and Zn
the effect is DOC
related
(originating from
sewage sludge)
01/06/2014 19
Modelling of Soil - Coal fly ash - Sewage sludge Cu behaviour of individual components
01/06/2014 20
Modelling of Cu behaviour in Soil – CFA -Sewage sludge mixtures
Effect on Cu release entirely DOC related. Cu mobilised as Cu-DOC complex
Conclusions
A limited set of proper characterisation leaching tests allows to describe release behaviour from soil and soil amendments to improve evaluation of management options and assess possible impacts
Significant progress in understanding release controlling processes has been made (see papers *)
Many substances are solubility controlled, thus providing a good understanding of effects at longer term.
Dissolved organic carbon proves to be a major factor in ecotox response of organisms and plants.
The multi-element multi-phase chemical reaction transport modelling is a challenge, but a highly rewarding one, when the behaviour of contaminated sites can be modelled at lab and field scale.
01/06/2014 21
* Dijkstra et al, Environ. Sci. Technol. (2009) 43, 6196-6201; Dijkstra et al, Applied
Geochemistry 23 (2008) 1544–1562; Dijkstra et al, Appl. Geochem. (2006) 21, 335 – 351;
Centioli et al, Ann Ist Super Sanità (2008) Vol. 44, No. 3: 252-257.
Recommendations
Emphasize leaching based judgment as opposed to content based judgment for management choices and environmental impact from soil amendments
Soil amendments are different depending on the nature of the material, but similar types can be compared and bringing together information pertaining to specific mixtures makes sense
For several types of admixtures already available full characterisation leaching data should be used, including data for various coal fly ashes and different types of sewage sludges
Geochemical modelling of soil with admixtures should be used in conjunction with actual testing and analysis to provide economic efficiency
Carry out leaching characterisation on composite samples from an agricultural site and some spatially distributed samples by a single step test to assess the nature of release controlling factors for the key contaminants
Develop benchmark characterisation data for amended soils with specific admixtures - LeachXS Lite (free) can provided such option as the database structure is designed to handle content and leachability data.
01/06/2014 22
References
01/06/2014 23
Andrew C. Garrabrants, David S. Kosson, Leonard Stefanski, Rossane DeLapp, Paul F.A.B. Seignette,
Hans A. van der Sloot, Peter Kariher, and Mark Baldwin. Interlaboratory Validation of the Leaching
Environmental Assessment Framework (LEAF) Method 1313 and Method 1316. EPA-600/R-12/623
(2012).
Andrew C. Garrabrants, David S. Kosson, Leonard Stefanski, Rossane DeLapp, Paul F.A.B. Seignette,
Hans A. van der Sloot, Peter Kariher, and Mark Baldwin. Interlaboratory Validation of the Leaching
Environmental Assessment Framework (LEAF) Method 1314 and Method 1315. EPA-600/R-12/624
(2012).
Carter, C.M., van der Sloot, H.A. and Cooling D. pH dependent extraction of soils and soil amendments to
understand the factors controlling element mobility - New approach to assess soil and soil amendments.
European Journal of Soil Science. European Journal of Soil Science, August 2009, 60, 622–637.
Postma J.F., van der Sloot, H.A. and van Zomeren A. Ecotoxicological response of three waste samples
in relation to chemical speciation modelling of leachates. In : Ecotoxicological characterization of waste –
Results and experiences from a European ring test. Eds: J. Römbke, R. Becker & H. Moser, Springer
Science+Business Media, Inc. Norwell (MA), 2009.
H.A. van der Sloot Harmonisation of leaching/extraction procedures for sludge, compost, soil and
sediment analyses. In: Methodologies for Soil and sediment fractionation studies. Ed. P. Quevauviller.
Royal Society of Chemistry, 2002, pp. 142-170.
01/06/2014 Second International Slag Valorisation Symposium │ Hans van der Sloot, Andre van Zomeren, Rob Comans and
Ole Hjelmar 24
For three waste samples besides ecotox testing with
aquatic and terrestrial organisms, a combination of a pH
dependence (TS 14429) and a percolation test
(TS14405) was carried out
With chemical speciation modelling (LeachXS-Orchestra),
partitioning between dissolved (free and DOC associated)
and solid phases (solid organic matter, clay surfaces,
iron oxides and minerals) was calculated and the
outcome compared with ecotox data.
Unique Set of Leaching Experiments and Ecotox Measurements
Postma J.F., van der Sloot, H.A. and van Zomeren A. Ecotoxicological response of three
waste samples in relation to chemical speciation modelling of leachates. In : Ecotoxicological
characterization of waste – Results and experiences from a European ring test. Eds: J.
Römbke, R. Becker & H. Moser, Springer Science+Business Media, Inc. Norwell (MA), 2009.
Cu leaching from treated wood
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Cu as function of pH
Wood UBA (pH stat TS14429) Model description at L/S=10
Wood UBA (Column TS14405) Model prediction at L/S=0.3
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid-solid, Cu
Free DOC-bound POM-bound FeOxide
Release of Cu from wood is controlled completely by particulate and dissolved organic matter
Copper as primary toxicity in undiluted eluates from CCA treated wood
EC50 copper (mg/l)
TU-values for copper
Microtox 0,13 170 D. magna 0,024 919 P. subcapitata 0,15 147
Toxic Unit TUi (Species) = Ci/EC50,i
Leaching at L/S=10 mL/g in DI water
Conclusion: Toxicity is likely caused by copper,
interaction with DOC varies with dilution
Dafnia magna, copper and wood
Test solutions (vol%) 100 0.50 0.20 Total Cu (mg/l) 22.1 Free Cu 0.5 Total Cu, test solution 0.110 0.044 "Expected" free-Cu 0.002 0.001 "Modelled" free-Cu 0.015 0.006 (%) 2.1 13.6 13.6
% Free Cu
Table 4.1 Total PAH in relation to “ available” and leachable PAH at own pH of SOI sample.
Parameter Total
Concentration ug/l at
L/S=10
Leached in mg/kg
% Available % Leachable
mg/kg pH12 Own pH pH12# Own pH for leaching at own pH
Anthracene 23.4 5.180 1.521 0.0518 0.0152 0.2214 0.0650
Benzo(a) anthracene 87.2 17.585 1.659 0.1759 0.0166 0.2017 0.0190
Benzo(a)pyrene 59 9.946 0.656 0.0995 0.0066 0.1686 0.0111
Benzo(b) fluoranthene 78.6 15.114 1.045 0.1511 0.0104 0.1923 0.0133
Benzo(ghi) perylene 34.7 1.783 0.434 0.0178 0.0043 0.0514 0.0125
Chrysene 69.4 17.480 1.701 0.1748 0.0170 0.2519 0.0245
Dibenz(ah) anthracene 9.37 0.671 0.858 0.0067 0.0086 0.0716 0.0916
Fluoranthene 181.6 36.616 10.006 0.3662 0.1001 0.2016 0.0551
Fluorene 4.16 2.637 0.990 0.0264 0.0099 0.6338 0.2381
Phenanthrene 69.1 25.317 0.469 0.2532 0.0047 0.3664 0.0068
Pyrene 146 27.814 6.889 0.2781 0.0689 0.1905 0.0472
# Considered to represent the "available" fraction for leaching
Comparison of PAH content, “availability” and actual leachability for gasworks soil SOI
Postma J.F., van der Sloot, H.A. and van Zomeren A. Ecotoxicological response of three
waste samples in relation to chemical speciation modelling of leachates. In : Ecotoxicological
characterization of waste – Results and experiences from a European ring test. Eds: J.
Römbke, R. Becker & H. Moser, Springer Science+Business Media, Inc. Norwell (MA), 2009.
Partitioning of organic contaminants in contaminated soil relevant for ecotox effect
Rather low proportion of organic PAHs/PCBs, etc.
free in solution, when natural organic matter is
present. Koc values used to describe partitioning.
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
[BAP] as function of pH
Lysimeter Pred Inorg Wastemix NL [BAP]
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid and solid , [BAP]
Free DOC-bound POM-bound
1.0E-09
1.0E-08
1.0E-07
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
[FLA] as function of pH
Lysimeter Pred Inorg Wastemix NL [FLA]
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid and solid , [FLA]
Free DOC-bound POM-bound
0
5E-09
1E-08
1.5E-08
2E-08
2.5E-08
3E-08
3.5E-08
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid and solid , [BAP]
Free DOC-bound POM-bound
0
1E-08
2E-08
3E-08
4E-08
5E-08
6E-08
7E-08
8E-08
9E-08
0.0000001
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Co
nce
ntr
ati
on
(m
ol/
l)
pH
Partitioning liquid and solid , [FLA]
Free DOC-bound POM-bound
