Development of emission limits for construction products in the Dutch Soil Quality Decree Rob Comans, Joris Dijkstra, Hans Meeussen (ECN) Anja Verschoor & Job Spijker (RIVM)
Outline 9 Introduction 9 Generic modelling approach major geochemical processes, models & parameters
CuOH+
+ Cu
– Cu2+
Cu
Cu2+
9 Application to contaminant leaching and speciation in soils 9 Application to environmental legislation: emission limits for construction materials 9 Uncertainties and research questions 9 Conclusions
[conc]
Road base
L/S
Introduction • Aim: to develop new environmental limits for emission from construction products • “Risk based approach” for calculation of new limit values: Emitted contaminant concentrations should not exceed protection level in upper meter of groundwater (POC) during a period of 100 years • Take “speciation” and “competition” of emitted contaminants in soil into account
Geochemical processes controlling fate of (leached) contaminants
Sources: Surface and Aqueous Geochemistry Group, Stanford, USA; PhD Thesis Ellen Fest (2007)
“Multi-surface”, predictive modelling of leaching processes “Available” concentrations: → Leaching/extraction at low pH (≈0.5) Major ion chemistry: pH, major (competing) ions, inorganic ligands (NIST-thermodynamic database)1
Experiment
Geochemical speciation modelling
Cu2+ database with stability constants
H+ (pH)
Dissolved organic matter: Humic and fulvic acids (NICA model)2 Reactive surfaces in the solid phase: • OM (humic/fulvic acids) (NICA model)2 • Fe/Al (hydr)oxides (Two layer SCM)3 • Clay particles (Donnan model) 1
computer program
Cu2+
+ Cu
assumptions
?
CuOH+ ?
(ORCHESTR A)4
Cu2+?
Modified after M. Gfeller & R. Schulin, ETH, Zürich
MINTEQ 4.0/NIST; 2 Milne et al. (2003); 3 Dzombak & Morel (1990); 4 Meeussen (2003)
Concentration
Approach to identification of leaching processes
“availability”
? pH
Concentration
pH-dependent solubility
! pH
Model See also: Dijkstra et al. (2004) Environ. Sci. Technol. 38, 4390-4395.
Leaching of metals from contaminated soils: blind prediction 1.E-02
1.E-03
1.E-01
Cu
concentration (mol/L)
Ni 1.E-03
Ni(OH)2(s)
1.E-04
Zn(OH)2(s)
1.E-03
1.E-04 1.E-05
1.E-04
1.E-06
1.E-05
1.E-05 1.E-06
1.E-06 1.E-07
1.E-07 1.E-08
1.E-07 1.E-08
1.E-08 0
2
4
6
8
10
12
0
2
4
pH
6
8
10
12
0
2
4
6
8
pH
pH 1.E-04
1.E-04
Pb
Cd concentration (mol/L)
Zn
1.E-02
1.E-05
data soil I
Pb(OH)2(s)
data soil IV
1.E-05
data soil VII
1.E-06
1.E-06
model soil I
1.E-07
model soil IV 1.E-07
model soil VII
1.E-08
total soil I
1.E-08
1.E-09
total soil IV total soil VII
1.E-09
1.E-10 0
2
4
6 pH
8
10
12
0
2
4
6
8
10
12
pH
Dijkstra et al., Environmental Science and Technology (2004), 38, 4390-4395
10
12
Development maximum emission values Dutch Soil Quality Act Concentration
c = c0 * e-k* t
Emission from construction:
Release criteria
Time
Transport through soil: + Cu
– Cu2+ Cu2+
20 regulated elements
Cu
Concentration in groundwater (t=100 y / t=1000 y)
Protection level Concentration
CuOH+
Time
Major Dutch soil types: sand, clay, peat Stone database (Alterra) Specific depth profiles: • pH • Reactive mineral/ -organic surfaces • Hydrological properties
http://www.bodemdata.nl/
3.00E-08
8.00E-03
5.00E-07
Chloride
Copper
Arsenic
Concentration [M] depth 0.95-1.95 m
7.00E-03
2.50E-08 4.00E-07
6.00E-03
Groundwater limit Groundwater limit
2.00E-08 5.00E-03
Groundwater limit
3.00E-07
1.50E-08
4.00E-03
3.00E-03
Kd = low +average + high
2.00E-03
Orchestra sandy soil, peat soil, clay soil
2.00E-07
1.00E-08 Kd = low Orchestra sandy soil
5.00E-09
1.00E-07
1.00E-03
0.00E+00
0.00E+00 0
20
40
60
Time (years)
80
100
0
20
40
60
Time (years)
80
0.00E+00 100 0
20
40
60
Time (years)
80
100
3.00E-08
7.00E-07
Copper - 1000 years Concentration [M] depth 0.95-1.95 m
Concentration [M] depth 0.95-1.95 m
Copper - 100 years 2.50E-08
2.00E-08 Groundwater limit
1.50E-08
1.00E-08
5.00E-09
6.00E-07 Kd high Kd average
5.00E-07
Kd low orchestra sand orchestra peat
4.00E-07
orchestra clay
3.00E-07
2.00E-07
1.00E-07 Groundwater limit
0.00E+00
0.00E+00
0
20
40
60
Time (years)
80
100
0
200
400
600
Time (years)
800
1000
Average concentration [M] 0.95-1.95 m depth
Vikings attack Holland (1000 A.D.)
Holland part of France (1810-1813) WASCON 2009
0
200
400
600
800
Time (years)
“Validation”, “verification” only possible for parts of the approach Lab scale: wide range of conditions (pH-static, dynamic) How representative are assumed soil properties? Further research initiated through these results: Processes and parameters (e.g., organic matter characterization) Uncertainty analysis, communication of uncertainty in predictions
1000
Sensitivity of emission value to soil properties 10
Hg Cu
Factor of change emission value
Cd
As
Pb
1
1 = not sensitive <1 = more stringent
0.1 pH - 0.5 pH + 0.5 POM x 0.5 DOM x 0.5
> 1 = less stringent 0.01
contaminant
Sandy soil
Zn
Uncertainty in model predictions – Monte Carlo analysis ¾Key parameters: e.g. contaminant availability, reactive surfaces, reactive fraction of DOC, competing ions
¾Thermodynamic constants: e.g. solubility, complexation, sorption
Fe
Cd 1.0E-01
data model MC
concentration (mol/L)
concentration (mol/L)
1.0E-05 1.0E-06 1.0E-07 1.0E-08
1125 m1125 MC
1.0E-02 1.0E-03 1.0E-04 1.0E-05 1.0E-06
1.0E-09 0
2
4
6 pH
Dijkstra et al., (2009), in prep.
8
10
0
2
4
6 pH
8
10
Conclusions 9 Multi-surface geochemical modelling based on fundamental thermodynamic parameters (no fitting!) → generic approach (variety of contaminated materials), e.g. for: ¾ process identification ¾ environmental risk assessment 9 New direction in development of environmental (emission) limits in The Netherlands: “mechanistic” geochemical modelling 9 Dominant role of (dissolved) organic carbon (humic and fulvic acids) in contaminant speciation and leaching from soils and other contaminated materials 9 Quantitative accounting of uncertainties in model predictions required
Thank you for your attention!
Regeling bodemkwaliteit (Staatscourant 20/12/2007, 247, p 67)
Evaluation model approach for inorganic soil contaminants 1E-03
1E-03
1E-04 concentration (mol/L)
Sn 1E-05
1E-04
1E-04
1E-06
1E-05
1E-05
1E-07
1E-06
1E-06
1E-08
1E-07
1E-07
1E-09
1E-08
1E-08
1E-10
1E-09
1E-09
1E-03
1E-02
1E-03
Co
concentration (mol/L)
Ba 1E-03
As
1E-04
1E-04
1E-05
1E-04
1E-05
1E-06
1E-05
1E-07
1E-06 1E-06
1E-08 1E-07
1E-07
1E-09 1E-10
1E-08
1E-08 1E-03
0
1E-04
V concentration (mol/L)
Se
Cr
model soil I (vanadyl)
1E-04
2
1E-06 1E-06 1.0 E- 0 3 1. 0 E- 0 5
1E-07 1E-07
1. 0 E- 0 7 1.0 E- 0 9 0
1E-08
1E-08 1E-09
1E-09 2
4
6 pH
8
10
6
8
10
12
1E-05
1E-05
0
4
Sb
12
0
2
4
6
8
10
data soil I data soil II data soil III data soil IV data soil V model soil I model soil II 2 4 6 8 1012 model soil III pH model soil IV model soil V
12
pH
Dijkstra et al., (2009), submitted to Environmental Science and Technology
………………Thank you for your attention!
Regeling bodemkwaliteit (Staatscourant 20/12/2007, 247, p 67)
Additional slides
Limitations of Kd (1)
concentration (mol/L)
1.E-05
Kd = [Cd]soil/[Cd]solution
1.E-06
Kd
assumption = constant!
1.E-07 CuOH+
1.E-08
+ Cu
– Cu2+
1.E-09
Cd
1.E-10 0
2
4
6 pH
8
10
12
Cu2+
Cu
Multi-surface versus Kd 2.E-08
Molar concentration (depth = 0.95-1.95 m)
Groundwater limit value
2.E-08
Kd = low
1.E-08
Orchestra (Dutch sandy soil) Kd = average 5.E-09
Kd = high
0.E+00
0
200
400
600
Time (years)
800
1000
Speciation of heavy metals in contaminated soils Fulvic acid Humic acid
iron- and aluminum (hydr)oxides Pb
Solid phase
mol/L sorbed
Cu 6.0E-05
5.0E-05
5.0E-05
4.0E-05
4.0E-05
3.0E-05
3.0E-05
2.0E-05
2.0E-05
1.0E-05
mol/L solution
1.0E-05
In solution
0.0E+00
0.0E+00
1.0E+00 9.0E-01 8.0E-01 7.0E-01 6.0E-01 5.0E-01 4.0E-01 3.0E-01 2.0E-01 1.0E-01 0.0E+00
1.0E+00 9.0E-01 8.0E-01 7.0E-01 6.0E-01 5.0E-01 4.0E-01 3.0E-01 2.0E-01 1.0E-01 0.0E+00 0
“free”
CLA Y SHFO SFA SHA
2
4
5
(Me+2)
6
7
8
10
pH
Humic acid Fulvic acid
FREE INORG DFA DHA
0
2
4
5
6
7
8
10
pH
Inorganic complexes, e.g. Me(OH)2 (aq)
Dijkstra et al., Environmental Science and Technology (2004), 38, 4390-4395
Afleiding maximale emissiewaarden Bouwstoffen (2005-2006)
Afleiden emissiecriteria zodanig dat grondwater wordt beschermd
Bodem
Concentratie
Beschermingsniveau (MTT-waarde)
Emissie uit bouwproduct
Tijd
Grondwater
“Gangbare” benadering transportprocessen in de bodem
Kd- benadering: “K” = constante, “d” = distributie, verdeling Totaalconcentratie (mg/kg) Kd (L/kg) = Opgeloste concentratie (mg/L) Voordeel: eenvoudig Nadelen: Totaal (mg/kg)
• geen effecten van niet-lineariteit, pH, speciatie, competitie
• Kd- waarden niet geldig voor “alle” bodems Opgelost (mg/L) Source: Surface and Aqueous Geochemistry Group, Stanford, USA
Key to generic modelling approach: contaminant speciation temperature ionic strength composition time (“available” fractions) pH CuOH+
solid particles
+
(reactive mineral and organic surfaces)
Cu
– Cu2+ Cu2+
Cu
transport in soil and groundwater uptake by plants and (micro)organisms
Naar: M. Gfeller & R. Schulin, ETH, Zürich
organische ligands (humic- and fulvic acids)
Gemiddelde concentratie [M] 0.95-1.95 m diepte
Grondwater criterium Kd Hoog Kd Gemiddeld Kd Laag
Kd (laag)
Kd (gemiddeld) Kd (hoog)
0
200
400
600
Tijd (Jaren)
800
1000
NL bodemtypes: zand, klei, veen
STONE- database (Alterra)
pH
% org stof
Resultaat afleiden emissiecriteria bouwstoffen Chloride
Arseen
Gemiddelde concentratie [M] 0.95-1.95 m diepte
8.00E-03
Koper 2.00E-08
5.00E-07
grondwatercriterium 7.00E-03
4.00E-07 grondwatercriterium
6.00E-03
1.50E-08
grondwatercriterium 5.00E-03
3.00E-07 1.00E-08
4.00E-03
2.00E-07
3.00E-03 Zandgrond 2.00E-03
5.00E-09
Veengrond
1.00E-07
Kleigrond 1.00E-03
0.00E+00 0
20
40
60
Tijd (Jaren)
80
0.00E+00 100 0
0.00E+00
20
40
60
Tijd (Jaren)
80
100
0
20
40
60
Tijd (Jaren)
80
100
Wat beinvloedt het resultaat? Beleidskeuzes randvoorwaarden berekening Tijdsperiode (25 jaar? 100 jaar? 1000 jaar?) Toetsdiepte (1m? 2m? 10m?) Middelen concentraties Kwaliteitseisen aan bodem en grondwater Representativiteit aangenomen bodemeigenschappen pH, organische stof, kleigehalte Onzekerheid in processen / parameters Thermodynamica niet altijd goed bekend
Beleidskeuzes - randvoorwaarden berekening 8.00E-07
2.00E-08
Koper – 1000 jaar
Koper – 100 jaar Gemiddelde concentratie [M] 0.95-1.95 m diepte
Gemiddelde concentratie [M] 0.95-1.95 m diepte
grondwatercriterium
1.50E-08
Eigenschappen zandgrond
1.00E-08
Eigenschappen veengrond
Eigenschappen kleigrond 5.00E-09
6.00E-07
4.00E-07
2.00E-07
grondwatercriterium 0.00E+00
0.00E+00 0
20
40
60
Tijd (Jaren)
80
100
0
200
400
600
Tijd (Jaren)
800
1000
Onzekerheid processen / parameters Thermodynamische databases (bv MINTEQ, NIST) • Zeer volledig voor gebruik in Bbk • Onvolledig voor sommige stoffen (bv: antimoon) • Interne inconsistenties (cyanide, vanadium) “Reactiviteit” • Welk deel van organische stof is reactief? • Welk deel van een metaal in de bodem is reactief (beschikbaar)? Hydrologische processen • Voorkeursstroombanen
Conclusies en vooruitblik Eerste keer dat “mechanistische” modellen zijn gebruikt voor normstelling in het bodembeleid Benadering geschikt voor lokatiespecifieke en generieke risicobeoordeling Betere link tussen fundamenteel onderzoek (WUR/ECN) en beleid Goede vooruitzichten benadering op internationaal niveau (o.a. EU Bouwproductenrichtlijn) Transparantie: ORCHESTRA bouwstoffenmodel in LeachXS Samen met Alterra /RIVM wordt gewerkt aan verbeterde karakterisering gevoelige parameters/processen en validatie
Geochemical processes controlling fate of (leached) contaminants
Source: Surface and Aqueous Geochemistry Group, Stanford, USA
Application of new rapid method for (dissolved) organic matter reactivity* Clay soil (Wageningen, NL)
Sandy soil (Haren, NL) 10-30 cm
0-40 cm
30-60 cm
40-80 cm 60-90 cm
80-120 cm
90-120 cm
0
20
40
60
80
100
Concentration [mg/L]
0
120
5
10
HA FA Hy HON
10-40 cm
0
200
400
600
20
Concentration [mg/L]
Peat soil (Zegveld, NL)
0-10 cm
800
Concentration [mg/L] *) van
15
Zomeren & Comans (2007) Environ. Sci. Technol. 41, 6755-6761.
1000
25
30
ORCHESTRA emission values 1000
“immobile”
pH-sensitive
OM-sensitive
standard pH-0.5 pH+0.5 POC*0.5 DOC*0.5
100
EL/S=10 [mg/kg]
10
1
0.1
0.01
0.001 Sb
As
Ba
Cd
Cr
Co
Cu
Hg
Pb
Mo
Ni
Se
Sn
V
Zn
CN
Br
Cl
F
SO4
