The Global Symposium on Soil Pollution #GSOP18 | 2 - 4 May 2018 | FAO Hq Ms. Esther Goidts, Ministry of the Environment of Wallon Region/Ms. Marie Jailler, SPAQuE, Belgium

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2. Public Administration of Wallonia agriculture natural resources environment
Setting thresholds for soil pollutants : experience from
legal implementation in Wallonia and specific issues
around Arsenic and Lead (BELGIUM)
Esther GOIDTS (SPW), Marie JAILLER (SPAQυE), Suzanne REMY (ISSeP)

3. Outline
1) Soil thresholds as a tool
2) Definition of thresholds in Wallonia (Belgium)
3) As & Pb issues
4) Conclusions
Public Administration of Wallonia agriculture natural resources environment
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4. 1) Soil thresholds as a tool
Soil thresholds = limits above which a risk can occur /
(Soil Screening Values) triggers for actions
But … * many ways to calculate them
* depend on pollutants, soil characteristics, land use,
target to protect
Models for risk assessment exist
But… many hypothesis are taken, and validation is often
missing due to the various complexity of the site
(sources / pathways / receptors)
 Models alone are not enough, expert-based system is needed, with a
tiered approach
Tier 1 – soil screening values ; Tier 2 – site-specific risk assessment
Public Administration of Wallonia agriculture natural resources environment
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5. 2 – Soil thresholds in Wallonia - context
Public Administration of Wallonia agriculture natural resources environment
General
localisation
of Belgium
Administrative regions in
charge of environmental &
agricultural competences
=> Different sets of soil
thresholds for each region!
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6. 2 – Soil thresholds in Wallonia - context
Soil?
Angleur - 1855 (CHST)
Long history of
industrial activities
• XVIII & XIXth century
(coal and metal mining)
Atmospheric emissions
Waste production
Waste water
...
Public Administration of Wallonia agriculture natural resources environment
=> brownfields &
landfills mainly
situated in Hainaut
& Liège provinces
Angleur
As, Cd, Cu,
Pb, Zn, …
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7. 2 – Soil thresholds in Wallonia - context
Angleur - 1855 (CHST)
Long history of
industrial activities
• XVIII & XIXth century
(coal and metal mining)
• Laws on mines and quarries1919
• Waste decree / Code of Environment => Landfills, big activities/
industrial installations
1985
• Regulation on Protection at works – gas stations /
Decree Environmental Permit environnement
1999
• Soil decree  Potentially polluting activities/installations (233)
Triggers for site investigation/remediation
 Soil thresholds
2008 / 2018
• Law on renovation of economic wasteland => Very few environmental
concerns
1978
• Revision of the Land Planning Code (soil pollution management
for economic wasteland)
=> Distinction between heavily polluted sites (SPAQuE) and
moderately polluted sites (SPW/DGO4)
2004
=> 1st intervention of belgian legislator• Law on reallocation of coal sites1967
• Integretion of economic wasteland into Land Planning Code -
distinction between remediation and renovation
1987 -
1995
Public Administration of Wallonia agriculture natural resources environment
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8. 2 – Soil thresholds in Wallonia – calculation 2008
Thresholds function of:
- Pollutants : 50 (metals, BTEX, PAH, mineral oil, chlorinated solvents and cyanides)
- Land uses : 5 (Type I – natural, Type II – agricultural, Type III – residential, Type IV –
recreational & commercial activities, Type V – industrial)
- Receptors : 3 (human health - VSH, aquifers - VSN, and terrestrial ecosystems - VSE)
- Soil characteristics : 1(standard soil)
Model
Sources Pathways Receptors
Origin (activities,
geochemical background)
Pollutants content
Human health (TRV)
Water (EU GW directive)
Ecosystems (NOEC-EC10)
Output:
Risk
Reverse modelling (Risc-Human)
VS Min (VSH, VSN, VSE), QL laboratory, gradual LU sensitivityVR VI
Annex
Soil
Decree
Public Administration of Wallonia agriculture natural resources environment
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9. 2 – Soil thresholds in Wallonia – calculation 2018
Thresholds function of:
- Pollutants : 50 (metals, BTEX, PAH, mineral oil, chlorinated solvents and cyanides)
- Land uses : 5 (Type I – natural, Type II – agricultural, Type III – residential, Type IV –
recreational & commercial activities, Type V – industrial)
- Receptors : 3 (human health - VSH, aquifers - VSN, and terrestrial ecosystems - VSE)
- Soil characteristics : 1(standard soil)
Model
Sources Pathways Receptors
Origin (activities,
geochemical background)
Pollutants content
Output:
Risk
Reverse modelling
VS Min (VSH, VSN, VSE), QL laboratory, gradual LU sensitivityVR VI
Annex
Soil
Decree
Public Administration of Wallonia agriculture natural resources environment
-> 8
background concentration
Human health (TRV)
Water (EU GW directive)
Ecosystems (NOEC-EC10)
S-Risk
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10. 2 – Soil thresholds in Wallonia – results 2018
Public Administration of Wallonia agriculture natural resources environment
• Out of 255 thresholds in 2008,
50% increased (mineral oil, PAH)
~30% same (limiting factor from aquifers)
~20% decreased (heavy metals, chlorinated solvents, cyanids, ethylbenzene)
=> As & Pb
• Further discussion is needed => no change of legal thresholds for
Type I-II-III for now (current research on problematic pollutants)
• Raising issues with urban agriculture / gardening in former industrial
surroundings => URBAN SOIL & SANISOL research projects
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11. 3 – As and Pb issues
Public Administration of Wallonia agriculture natural resources environment
What’s happening for Arsenic (residential land use)?
2008
Soil Decree n°1
Threshold value in soil
= 109 mg/kg
2017-2018
Soil Decree n°2
Threshold value in soil
= 0,16 mg/kg
Oral Toxicity Reference Value
= 2,14 µg/kg.j (WHO)
Oral Toxicity Reference Value
= 2,80 (mg/kg.j)-1
(Health Canada)
---- 0,004 µg/kg.j for 10-5
Carcinogenic effect and Oral Toxicity Reference Value / 600
based on a study of 40 000 Taiwanese exposed to arsenic in drinking water reaching
1800 µg/L (Tseng et al. 1968, Tseng 1977)
 Does bioavailability of arsenic depend on natural / polluted soil, its
chemical speciation ?
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12. 3 – As and Pb issues
Public Administration of Wallonia agriculture natural resources environment
What’s happening for Lead (residential land use)?
2008
Soil Decree n°1
Threshold value in soil
= 196 mg/kg
2017-2018
Soil Decree n°2
Threshold value in soil
= 1,41 mg/kg
Oral Toxicity Reference Value
= 3,6 µg/kg.j (WHO) ≈ blood
level of 100 µg/L
Oral Toxicity Reference Value
= 0,063 (mg/kg.j)-1
(from EFSA with 0,63 µg/kg.j
≈ blood level of 15 µg/L)
Oral Toxicity Reference Value / 60
based on a growing number of scientific studies showing adverse effects of lead at
blood lead level < 100 µg/L : neurodvp / cardiovascular / renal
 Other sources of lead to consider in the global exposure
 New blood lead level of concern (USA, France) ?
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13. 3 – As and Pb issues
Public Administration of Wallonia agriculture natural resources environment
HUMAN HEALTH RISK ASSESSMENT
ARSENIC AND LEAD
mg/kg ARSENIC LEAD
VSH previous version – residential
land use
109 196  200
VSH new version – residential land
use
0,16 1,41
Natural background
(Arithmetic mean of 160 sampling
points)
12 25
Peri-industrial background
(Arithmetic mean of 800 sampling
points)
10 - 21 except in
Aubange area (52)
125 - 425
Peri-industrial background (90th
percentile of 800 sampling points)
13 - 36 except in
Aubange area
(103)
280 - 875
Limitation of the risk assessment  risk management
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14. 3 – As and Pb issues
Public Administration of Wallonia agriculture natural resources environment
What does it mean in practice for Arsenic ? -> risk management ->
Map showing the soil background concentration distribution in Wallonia
Aubange area
(natural +
anthropogenic
sources)
mean = 52
mg/kg
90th percentile
=103 mg/kg
Natural background =
12 mg/kg
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15. 3 – As and Pb issues
Public Administration of Wallonia agriculture natural resources environment
What does it mean in practice for Lead ? -> risk management ->
Map showing the soil background concentration distribution in Wallonia
Peri-industrial
area (along
Meuse and
Sambre rivers)
125 mg/kg <
Arithmetic mean
< 425 mg/kg
Natural background =
25 mg/kg
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16. 4 - Conclusions
Public Administration of Wallonia agriculture natural resources environment
 Soil thresholds are usefull as triggers for actions (site
investigation, remediation) but site-specific risk assessment has
to be undertaken for problematic situations
 Modelling helps defining soil screening values but technical
feasability, sensivity of the land use and measured values must
be taken into account
 Update of soil thresholds in Wallonia showed that As and Pb
are of concern because new thresholds (model + benchmark
dose limits by EFSA) are lower than background concentration
levels => risk management needed
 Increase of urban agriculture interest raises public health
issues, new research is needed
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17. Public Administration of Wallonia agriculture natural resources environment
Thank you for your attention!
Questions / Comments?
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