leaching behaviour and potential for … · leaching behaviour and potential for geochemical and...

LEACHING BEHAVIOUR AND POTENTIAL FOR GEOCHEMICAL

AND TRANSPORT MODELLING OF CONTAMINANTS IN SOIL AND SEDIMENTS IN RELATION TO

ENVIRONMENTAL IMPACT ASSESSMENT

H.A. van der Sloot, J.J. Dijkstra, J.C.L. Meeussen, and R.N.J Comans

ECN – Environmental Risk AssessmentPetten, The Netherlands

SEDNET, San Sebastian, 10 - 11 June 2004

- Too many leaching/extraction tests addressing the same question

- Too many ways of data representation

- Too limited relation of test conditions with the actual problem

- Too limited use and relevance of the vast amount of leaching test data generated annually in the industry and research (missing parameters!)

- Key information relevant to the outcome and possible interpretation of a leaching test often not reported (pH, EC, Eh, DOC)

MAIN CONCERNS IN RELATION TO LEACHING TEST USE AND DEVELOPMENT

STRONG NEED FOR HARMONISATION OF LEACHING TEST METHODS AND DATA EVALUATION!

TYPICAL QUESTIONS FOR SEDIMENTSRelease from contaminated sediment under water

Release from contaminated sediment brought on land

Release from contaminated sediment used as fertilizer

Release of treated contaminated sediment by

cement stabilisation

bitumen encapsulkation

sintering

vitrification

co-firing in cement kiln

RELEVANT TYPES OF LEACHING TESTS

TANK LEACH TEST (MONOLITH) en CGLT.

NEN 7345EN in development

PERCOLATION LEACHING TEST

(GRANULARPrEN 14405)

BATCH LEACHING TEST (GRANULAR)

EN12457 (1-4) pH STAT

TEST

Controllingfactors

Modellingleaching

Validationverification

Evaluation

Conclusions

ScenarioDescription

Materialcharacterization

pH DEPENDENCE TEST: BATCH MODE ANC and COMPUTER CONTROLLED

prEn 14429 PrEn xxxx (in enquiry)

Methodology

ENV 12920

Limited number of tests will cover 80- 90% of the questions for a wide range of materials

JUDGEMENT 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

Lea

ched

(mg/

kg)

Ni

"Total"

0

10

20

30

40

50

60

70

80

1 3 5 7 9 11 13

pH

Lea

ched

(mg/

kg)

PrEn14429PrEN 14429EN12457-2CaCl2SCE

Ni

Total (HF, HClO4)

Total (HNO3, HClO4)

Total (HNO3,tef lonbomb)

Total (A qua Regia)

Log-scale Linear-scale

Relevant pH domain

CEN/TC 292 -ENV 12920

pH DEPENDENCE TEST TO ASSESS SENSITIVITY TO CHANGES IN pH pH stat and “ANC” mode

TEST CONDITIONS ANC MODE:

BATCH TEST

8 FINAL pH VALUES (pH 4-12)

LEACHANT: PREDETERMINED AMOUNTS OF ACID OR BASE

LIQUID TO SOLID RATIO (L/S) = 10

RESULTS IN mg/l (GEOCHEMICAL MODELLING) OR mg/kg (RELEASE EVALUATION)

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


CEN/TC 292 -ENV 12920

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


pH DEPENDENCE TEST TO ASSESS SENSITIVITY TO CHANGES IN pH,

EH AND TEMPERATURE

TEST CONDITIONS RELATED TO DIFFERENT EXPOSURE CONDITIONS

Relevant pH domains for assessing different questions in relation to different types of impact

Contaminated river sediment

Total

0.01

0.1

1

10

100

1000

0 2 4 6 8 10 12 14pH

Lea

ched

(mg/

kg)

PrEN14429PrEN 14429NaNO3EDTAHacCaCl2EN 12457-2SCESCETotal composition

Cr

INGESTIONINHALATION

CEMENT STABILIZATION OF

CONTAMINATED SOIL

NATURAL SOIL

ACIDIC ENVIRONMENT

SOIL LIMING

ADVANTAGES OF pH DEPENDENCE TEST

- Identification of sensitivity of leaching to small pH changes

- Provides information on pH conditions imposed by external influences

- Basis for comparison of international leaching tests- Basis for geochemical speciation modelling- Provides acid neutralization capacity information- Mutual comparison of widely different materials to assess similarities in leaching behaviour

- Recognition of factors controlling release- For non-interacting species possible to assess sub-sampling error

Applicable to almost any material

CEN/TC 292 -ENV 12920

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


Liquid to solid ratio (L/S) related to a time scale by infiltration rate, density and height of application.

TEST CONDITIONS:Pre-equilibration after saturation for more than 48 hrs

Up-flow

L/S range 0.1 - 10 (100 - 1000 yrs)

Test data in mg/l or mg/kg cumulative

PERCOLATION TEST TO ASSESS LONG TERM RELEASE FOR GRANULAR MATERIALS

ADVANTAGES OF PERCOLATION TEST

- Identification of solubility control versus wash out- Indication of pore water concentrations relevant to field leachate from low L/S data

- Local equilibrium established quite rapidly - Basis for geochemical speciation modelling- Allows comparison with lysimeter and field data provided L/S value can be obtained from such measurements

- Projection towards long term behaviour possibleSolubility controlled releaseWash-out of non-interacting species

Applicable to many materials. Limited or not applicable to clayey soils and sediments (low permeability).

CEN/TC 292 -ENV 12920

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


TEST CONDITIONS:First step: pre-equilibration for 48 hrs at liquid to volume ratio: 5 Second step: leaching at low L/V ratio (1) for 24 hrsThen contact times: 2, 4, 8,16, 32 and 64 daysLeachant: demineralised water (own pH)

Expression of results in mg/m2 (cumulative)against time

TANK LEACH TEST OR COMPACTED GRANULAR LEACH TEST (CGLT) FOR MONOLITHIC MATERIALS (modified)

CGLT = Compacted Granular Leach Test

EXPERIMENTAL SET-UP

ADVANTAGES OF TANK LEACHING TEST OR COMPACTED GRANULAR LEACH TEST

- Relevant for materials with monolithic character (durable materials) or materials behaving as monolith (low permeability soil and sediments)

- Identification of solubility control versus dynamic leaching possible

- Isolation of surface wash-off effects- Quantification of intrinsic release parameters - Basis for reactive/transport modelling- Projection towards long term behaviour possible

Applicable to sediments, clayey soils, stabilised materials and construction materials produced

DEVELOPMENT OF STANDARDSEuropean:Granular waste compliance leaching test – EN 12457 1- 4 validated CEN TC 292 WG2 Monolith compliance leaching test – Tank leach test 3 days (in enquiry) CEN TC 292 WG2 pH dependence leaching test – 2004 for formal vote -PrEN 14429 CEN TC 292 WG6 Percolation test – 2003 formal vote - PrEN 14405 CEN TC 292 WG6 NWIP Dynamic leach test (similar to NEN 7345; in preparation) CEN TC 292 WG6 International:Batch tests and percolation test for soil materials(based on CEN TC 292 procedures; 2004 F-DIS) ISO TC 190 SC7 WG6

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


BASIC CHARACTERISATION TESTS

TANK LEACH TEST

(MONOLITH) and

COMPACTED GRANULAR

LEACH TEST.

PERCOLATION LEACHING TEST

(PrEN 14405)

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


GRANULAR MATERIALS

MONOLITHIC MATERIALS

or

pH DEPENDENCE TEST : BATCH MODE ANCprEn 14429 or

COMPUTER CONTROLLED

or

pH DEPENDENCE TEST : BATCH MODE ANCprEn 14429 or

COMPUTER CONTROLLED

CEN/TC 292 ENV 12920

Chemical speciation aspects Time dependent aspects of release

RELATIONSHIPS BETWEEN CHARACTERISATION TEST RESULTS, POTENTIALLY LEACHABLE AND TOTAL COMPOSITION FOR GRANULAR MATERIALS

Internal consistency and coherence of test data crucial

Zn

0.01

0.1

1

10

100

1000

0.1 1 10

LS (l/kg)L

each

ed (m

g/kg

)

Solubility control

Kd

Kd

0.01

0.1

1

10

100

1000

1 3 5 7 9 11 13pH

Lea

ched

(mg/

kg)

PrEn 14429SCE

A qua RegiaHNO3 Bomb

95%HNO3/5%HCLO4A qua Regia/HF/ Boric acid Microw ave

Series5

Ow n pH

Zn

Kd

RELEASE PROCESSES FROM MATERIALS

0.1

1

10

100

0.1 1 10 100

L/S (l/k g)

Lea

ched

(mg/

kg)

F

SOLUB ILITY CONTROL

F0.1

1

10

100

4 6 8 10 12

pH

Lea

ched

at L

/S=1

0 (m

g/k

g)

0 .01

0.1

1

10

0.1 1 10 100

L/S (l/kg)

Con

cent

rati

on (m

g/l)

F

Cl100

1000

10000

4 6 8 10 12

pH

Lea

ched

(mg/

kg)

100

1000

10000

0.1 1 10 100

L/S (l/k g)

Cum

ulat

ive

rele

ase

(mg/

kg) Cl

WASH OUT

1

10

100

1000

10000

0.1 1 10 100

L/S (l/k g)

Con

cent

rati

on (m

g/L

) Cl

0.1

1.0

10.0

100.0

1000.0

1 3 5 7 9 11

pH

Lea

ched

(mg/

kg)

Rhine, NLRhine, NLElbe1 DElbe2 DRhine DSaar DSpain 1Spain 2

Ba0.001

0.01

0.1

1

10

100

1 3 5 7 9 11

pH

Lea

ched

(m

g/kg

)

Ni

COMPARISON OF SEDIMENT LEACHING CHARACTERISTICS

Marine and fresh water systems

0.1

1

10

100

1000

10000

1 3 5 7 9 11 13pH

Lea

ched

(m

g/k

g)

Zn

"T otal" Aqua Regia

0.01

0.1

1

10

100

1 3 5 7 9 11 13

pH

Lea

ched

(m

g/k

g)

Ni

0.01

0.1

1

10

100

1000

1 3 5 7 9 11 13pH

Lea

ched

(m

g/k

g)

V

0.01

0.1

1

10

100

1000

10000

100000

1 3 5 7 9 11 13

pH

Lea

ched

(m

g/k

g)

PrEN14429DuplicatecenCaCl2SCE

Al

COMPARISON OF DIFFERENT LEACHING TESTS WITH pH DEPENDENCE LEACHING TEST FOR A CONTAMINATED RIVER SEDIMENT


Controllingfactors leaching

Modellingleaching


Evaluation

Conclusions

ScenarioDescription

GEOCHEMICAL MODELLING

pH stat test andL/S = 10; t = 48 hr percolation test L/S=0.1-10Field leachate

Geochemical modelling

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


ORCHESTRA with extended MINTEQ database + NiccaDonnan

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

1.0E-01

1.0E+00

0 2 4 6 8 10 12 14pH

[Al]

(mol

/l)

LY S-NA UBoehmiteGibbs ite[C]LY S-NA U-ORGBoehmiteGibbs ite[C]

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

0.00001 0.0001 0.001 0.01 0.1 1 10

L/S (l/kg)

[Al]

(mol

/l)

NA U-COL BoehmiteGibbsite[C] NA U-COL-ORGA lbite[low ] BoehmiteGibbsite[C] NA U-LY SBoehmite Gibbsite[C]NA U-LY S-ORG BoehmiteGibbsite[C]

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0.01 0.1 1 10

L/S (l/kg)

[Al]

(mol

/l)FIELD-NA U LEA CHA TE

A l[OH]3[a]

BoehmiteGibbsite[C]

GEOCHEMICAL MODELLING USING ORCHESTRA

- JAVA based object oriented modelling environment (Meeussen)- Extended MINTEQA2 thermodynamic mineral database- Fe oxide sorption module (Dzomback)- Clay surface sorption module- NICCA DONNAN based POM and DOC association of metals

Cd1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 2 4 6 8 10 12 14pH

con

cen

trat

ion

(mo

l/L) Harbour sediment (Rhine)

Predic tive model

PrEN14429

Solid phase Cd

0.0E+00

1.0E-06

2.0E-06

3.0E-06

4.0E-06

5.0E-06

6.0E-06

7.0E-06

1187631pH

mo

l/L s

orb

ed

ClayFe-(hydr)oxidesPOM

Water phase Cd

0.0E+00

2.0E-01

4.0E-01

6.0E-01

8.0E-01

1.0E+00

1187631

pH

Par

titio

nin

g

OtherFreeDOM

Water phase Cd

0.0E+00

1.0E-06

2.0E-06

3.0E-06

4.0E-06

5.0E-06

6.0E-06

7.0E-06

1187631

pH

mo

l/L s

orb

edOtherFreeDOM

ORCHESTRA modelled solid phase and liquid phase speciation of Cdin a contaminated river sediment

Pb

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 2 4 6 8 10 12 14pH

con

cen

trat

ion

(mo

l/L)

Harbour sediment (Rhine)Predictive model

Solid phase Pb

0.0E+00

5.0E-05

1.0E-04

1.5E-04

2.0E-04

2.5E-04

1187631pH

mo

l/L s

orb

ed

ClayFe-(hydr)oxidesPOM

Wate r phase Pb

0.0E+00

2.0E-01

4.0E-01

6.0E-01

8.0E-01

1.0E+00

1187631

pH

Par

titio

nin

g

OtherFreeDOM

W ater phase Pb

0.0E+002.0E-054.0E-056.0E-058.0E-051.0E-041.2E-041.4E-041.6E-041.8E-042.0E-04

1187631

pH

mo

l/L s

orb

ed

OtherFreeDOM

ORCHESTRA modelled solid phase and liquid phase speciation of Pbin a contaminated river sediment

Cd

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

0 2 4 6 8 10 12

pH

conc

entr

atio

n (m

ol/L

)

Pb(OH)2(s)Pb

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

0 2 4 6 8 10 12

pH

data soil I

data soil IV

data soil VII

model soil I

model soil IV

model soil VII

total soil I

total soil IV

total soil VII

Zn(OH)2(s)

Zn

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

0 2 4 6 8 10 12

pH

Cu(OH)2(s)

Cu

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

0 2 4 6 8 10 12

pH

PREDICTION OF LEACHING TEST DATA FOR (CONTAMINATED ) SOIL BY GEOCHEMICAL SPECIATION

Dijkstra, J.J., Meeussen, J.C.L. and Comans, R.N.J. Leaching of heavy metals from contaminated soils: an experimental and modeling study. (Accepted.)

Test: PrEN 14429

Cu

0.0E+00

1.0E-04

2.0E-04

3.0E-04

4.0E-04

5.0E-04

6.0E-04

7.0E-04

CLAY

SHFO

SHA

mo

l/L s

orb

ed

0.0E+00

5.0E-05

1.0E-04

1.5E-04

2.0E-04

2.5E-04

121087642pH

FREE

INORG

DHA

mo

l/L in

so

luti

on

Pb

0.0E+00

1.0E-05

2.0E-05

3.0E-05

4.0E-05

5.0E-05

6.0E-05

7.0E-05

0.0E+00

5.0E-06

1.0E-05

1.5E-05

2.0E-05

2.5E-05

3.0E-05

3.5E-05

121087642pH

Dijkstra, J.J., Meeussen, J.C.L. and Comans, R.N.J. Leaching of heavy metals from contaminated soils: an experimental and modeling study. (Accepted)

GEOCHEMICAL SPECIATION OF LEACHING TEST DATA FOR (CONTAMINATED ) SOIL

ORCHESTRA with extended MINTEQ database + NiccaDonnan +HFO

0.1

1

10

100

0.1 1 10 100

Tim e(days)

Rel

ease

(mg/

m2)

Harbour Sediment (Rhine)

Ba

0.1

1

10

0.1 1 10 100

Time(days)

Rel

ease

(mg/

m2)

Cu

Compacted granular leach test NVN 7347

100

1000

10000

0.1 1 10 100

Tim e(days)

Rel

ease

(mg/

m2)

SO4 as S

0.1

1

0.1 1 10 100

Tim e(days)

Rel

ease

(mg/

m2)

Ni

COMPACTED GRANULAR LEACH TEST RESULTS FOR CONTAMINATED HARBOUR SEDIMENT (SEDIMENT UNDER WATER)

Potential for prediction of long term release

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1001

10

100

1000

10000

100000

1000000

0.1 1 10 1000.01

0.1

1

10

100

1000

10000

0.1 1 10 1000.01

0.1

1

10

100

1000

10000

0.1 1 10 1000.01

0.1

1

10

100

1000

10000

0.1 1 10 1000.01

0.1

1

10

100

1000

10000

0.1 1 10 1000.01

0.1

1

10

100

1000

10000

Time (days)

Cum

ulat

ive

rele

ase

(mg/

m2 )

UNTRATEDDREDGE

SPOIL

CEMENTSTABILIZED

DREDGESPOIL

BITUMENSTABILIZED

DREDGESPOIL

SINTEREDDREDGE

SPOIL

VITRIFIEDDREDGE

SPOIL

COMPARISON OF LEACHING BEHAVIOUR OF SEDIMENT (CGLT) AND TREATED SEDIMENT ACCORDING TO DIFFERENT TECHNIQUES WITH TANK TEST

TOTAL

POTENTIALLY LEACHABLE

RELEASE FROM MONOLITH

Log-

scal

e !

A robust and scientifically sound, while practical, framework for characterisation of environmental behaviour of soils, sludges, sediments, wastes and constructions materials in a range of applications and exposure scenarios is in development in EU and US

The framework is a tiered approach, allowing the user to select the level of testing and evaluation required based on the degree of conservatism needed, prior information available, and balancing costs of testing against benefits from more detailed information

FRAMEWORK

SCENARIO APPROACH IN JUDGING IMPACT

APPLICABLE TO:

SOIL,

SLUDGE,

SEDIMENT,

WASTE,

LANDFILL,

CONSTRUCT.

MATERIALS, etc

Lab, lysimeter, field data collection, data management, data formatting, storage and retrieval

Problem definition and test selection

pH, L/S & time dependence - redox, DOC, EC, ANC

Release with time Granular MonolithicPercolation related Surface area

Source term description

Impact evaluation subsoil and groundwater

Judgement and decision makingQC; Regulatory aspects

Treatment, Disposal, Utilization, Remediation end-points, long-term stewardship requirements

Expe

rt s

yste

m /

data

base

Dat

a in

tegr

atio

n b

etw

een

fie

lds

and

test

s, m

odel

ing

and

veri

fica

tion

ag

ain

st f

ield

dat

a

Physical , chemical, biological properties

Management Scenario Description – configuration, design specifications, infiltration, climate

ENV 12920

Concentration - pHChemicalspeciation

Redox informationEh – pHANC - pH

pH stat testRelease – pH

Individualconstructionmaterials

Percolation testRelease - L/S

LysimeterField data

Percolation testConcentration - L/S

LysimeterField data

Cum. release - L/SRelease modelling

L/S - time relationInfiltrationHydrology

Concentration - L/SChemicalspeciation

DATABASEPercolate fieldPilot dataLysimeter dataLab test data

Parametercorrelation

Time seriesfield pilot dataa.o. forcarbonation

DATABASE/EXPERT SYSTEM “CONSTRUCTION - Granular”

Modellingsoil and groundwaterimpact

STUDIES REGULATION

DATABASE/EXPERT SYSTEM - SEDIMENTS AND SOILS

CEN/TC 292 -ENV 12920

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


HIERARCHICAL APPROACH IN TESTING• Conservative Estimates (over-estimation of release)

– Total > Potential > Equilibrium ≥ Mass Transfer limited

• Characterization Testing– Detailed baseline evaluation of leaching behaviour for a class

of materials (data to be made available in expert system/database)

• Compliance Testing– Is the material tested the same as previously characterized

class of materials? (Always characterisation data as background)

– Prior characterization data available from similar material

• Quality Control Testing– Is the material changing over time or from batch to batch?– Prior characterization data available, history with compliance

testing (frequency of testing based on critical nature in view of regulation)

CEN/TC 292 -ENV 12920

Controllingfactors

Modellingleaching


Evaluation

Conclusions

ScenarioDescription


THE ULTIMATE MODEL VALIDATION IS A VERIFICATION IN THE FIELD AT AN ACTUAL FULL SCALE DEMONSTRATION

IN SOME CASES, MEASUREMENTS ON LONG TERM FIELD EXPOSED MATERIALS PROVIDES RELEVANT INFORMATION

IN MANY CASES, CONSISTENCY BETWEEN DATA FROM DIFFERENT TYPE OF TESTS AND BETWEEN DIFFERENT SOURCES WILL SUFFICE AS FIELD STUDIES WILL NOT BE POSSIBLE IN ALL CASES.

IN SOME CASES, COMPARISON WITH NATURAL ANALOGUES OR HISTORICAL INFORMATION IS POSSIBLE.

CRUCIAL VERIFICATION OF LABORATORY DATA WITH FIELD OBSERVATIONS

CONCLUSIONS

- In any leaching extraction test on soil or sediments as a minimum pH, EC, redox and DOC should be measured.

- Existing leaching/extraction tests, when placed in perspective to pH dependence leaching test, prove that they are largely governed by pH.

- The pH dependence leaching test has been shown to be a very powerful tool to assess a variety of properties relevant to judgement of environmental behaviour of soil and sediments in a range of utilisation and disposal scenarios.

CONCLUSIONS- The SCE when presented as a cumulative leached amount as function of pH matches generally well with the pH dependence test.

- The present geochemical speciation modelling now possible with ORCHESTRA goes well beyond the results and interpretation of SCE as more quantitative and justifiable partitioning can be obtained.

- The pH dependence test in combination with the speciation capabilities will provide new opportunities for bioavailability assessment as free and complexedmetals can be quantified.

CONCLUSION- Harmonisation of leaching tests across the different

fields (soil, waste, sludge, construction materials, etc) strongly needed.

- Leaching proves to be a more relevant property for environmental impact evaluation than composition and it is less sensitive to sampling errors due to solubility control.

- Hierarchy in testing needed in all fields to ensure fundamental knowledge when needed and simple approaches where possible.

- Although not discussed now many of the aspects mentioned are as relevant for organic contaminants as for inorganics. The key issue is avoiding loss of analyteby the equipment.

CONCLUSION

- The methods of analysis of inorganic and organic contaminants being developed in project HORIZONTAL can be very valuable in combination with the standardised leaching tests discussed here.

- Validation studies of characterisation test methods (not limited to soil and sediments) now available as European standards is needed to be able to quantify test performance.

- Sampling uncertainties sometimes over-stressed, as situations where solubility control is ruling can provide very consistent results from seemingly heterogeneous materials.

INFORMATION ON LEACHING AVAILABLE AT:

LEACHING BACKGROUND

www.leaching.net (Wascon 2003 workshop)

GRACOS

www.uni-tuebingen.de/gracos

LEACHING IN PROJECT HORIZONTAL

www.ecn.nl/library/horizontal

leaching behaviour and potential for … · leaching behaviour and potential for geochemical and...

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