Remediation of metal polluted Remediation of metal polluted

urban soils and evaluation of dangerurban soils and evaluation of danger

to human health assessed by to human health assessed by

in vitroin vitro oral bioaccessiblity testsoral bioaccessiblity tests

Roussel H.Roussel H., Waterlot C., Pruvot C., Bacquet M., , Waterlot C., Pruvot C., Bacquet M.,

Martel B., Leprêtre A., Ciesielski H., Philippe S., Martel B., Leprêtre A., Ciesielski H., Philippe S.,

Mazzuca M., Douay F.Mazzuca M., Douay F.

ContextContext

•• Historic Historic

contaminationcontamination

� Metaleurop Nord (Noyelles-Godault) = Lead smelter

� Umicore (Auby) = Zinc smelter

Pb isoconcentration curves (mg/kg)

ContextContext

Agricultural topsoils

ContextContext

•• Ratio of Ratio of UrbanUrban vs vs RegionalRegional agricultural agricultural topsoilstopsoils

•• Ratio of Ratio of UrbanUrban vs vs Local agricultural Local agricultural topsoilstopsoils

METALEUROP (Pb smelter)

UMICORE (Zn smelter)

0

20

40

60

80

100

120

140

Ag As Bi Cd Co Cr Cu Hg In Ni Pb Sb Se Sn Th Tl U Zn

0

1

2

3

4

5

6

7

8

Ag As Bi Cd Co Cr Cu Hg In Ni Pb Sb Se Sn Th Tl U Zn

ME

UM

ContextContext

•• SoilSoil ingestion ingestion withwith hand to hand to mouthmouth transfertransfer

6

Lead blood level (> 100 µg L-1)

� 10 to 15 % of children (2 to 4 years old, from 1994 to 2002)

� up to 30 % under the prevailing winds

� 2.4 % in 2004 after smelter closedown

But the actual mean lead blood level is still over the national mean value (42 µg L-1 instead of 27 µg L-1 respectively)

ContextContext

SoilSoil remediationsremediations

•• SoilSoil removalremoval

•• PhytomanagmentPhytomanagment

•• AmendmentsAmendments

AimsAims

•• Immobilize metals in soilsImmobilize metals in soils

•• Reduce metal bioavailability to biotaReduce metal bioavailability to biota

•• Lower children exposureLower children exposure

MaterialsMaterials and and methodsmethods

•• SoilSoil physicophysico--chemicalchemical parametersparameters

Garden pH CEC C/N Organic Matter CaCO3 total P2O5

cmol+/kg g/kg g/kg g/kg

1 7.1 22.5 14.8 72.5 7.69 1.29

2 7.8 13.8 21.2 97.8 32.70 2.07

Garden distance Sand Clay Cd Pb Zn

m % % mg/kg mg/kg mg/kg

1 ME 459 19.2 28.8 29.9 1830.2 1050

2 U 899 30.6 18.9 21.5 623.0 2970

2 urban topsoils were sampled (0-25 cm):

�Close to the Pb smelter (garden 1)�Close to the Zn smelter (garden 2)

MaterialsMaterials and and methodsmethods

•• 4 Amendment types4 Amendment types

–– InorganicsInorganics : :

•• PhosphatePhosphate

•• Fly ashFly ash

–– Organics : Organics :

•• D60D60

•• polypolyββCDCD--CTRCTR

MaterialsMaterials and and methodsmethods

–– 2 2 InorganicsInorganics : :

•• Phosphate (Phosphate (diammoniumdiammonium phosphate + phosphate +

hydroxyapatitehydroxyapatite ))

•• Fly ashFly ash

PhosphateDiammonium phosphate + hydroxyapatite

3,4Zn

40 700N

111 000P2O5

< 2Pb

< 0,5Cd

Concentration

(mg kg-1)Elements

3,4Zn

40 700N

111 000P2O5

< 2Pb

< 0,5Cd

Concentration

(mg kg-1)Elements

Applied dose: molecular ratio P/(Cd+Pb+Zn) = 3/5

Chemical Parameters

MaterialsMaterials and and methodsmethods

Fly ash

Silico-aluminate fly ashfrom Carling (SEDELINE®)

5 460S soluble (mg kg-1)

3,7Se

21,4As

0,87Hg

1,0Cd

142Pb

31,5Co

93,8Ni

168,5Cr

257Zn

717Mn

81Cu

122200Al

37900Fe

Total contents(mg kg-1)

1,92K+ échangeable (cmol+ kg-1)

14,55Mg2+ échangeable (cmol+ kg-1)

0,59Na+ échangeable (cmol+ kg-1)

101,4Ca2+ échangeable (cmol+ kg-1)

5,1CEC (cmol+ kg-1)

0,094P2O5 (g kg-1)

21CaCO3 total (g kg-1)

0,22N (g kg-1)

5 460S soluble (mg kg-1)

3,7Se

21,4As

0,87Hg

1,0Cd

142Pb

31,5Co

93,8Ni

168,5Cr

257Zn

717Mn

81Cu

122200Al

37900Fe

Total contents(mg kg-1)

1,92K+ échangeable (cmol+ kg-1)

14,55Mg2+ échangeable (cmol+ kg-1)

0,59Na+ échangeable (cmol+ kg-1)

101,4Ca2+ échangeable (cmol+ kg-1)

5,1CEC (cmol+ kg-1)

0,094P2O5 (g kg-1)

21CaCO3 total (g kg-1)

0,22N (g kg-1)

Applied dose: 6%

Chemical parameters

MaterialsMaterials and and methodsmethods

MaterialsMaterials and and methodsmethods

–– Organics : Organics :

•• D60 (industrial polymer made of D60 (industrial polymer made of

polyacrylatepolyacrylate from ATOCHEM)from ATOCHEM)

•• polypolyββCDCD--CTR CTR (synthesised polymer (synthesised polymer

made of made of cyclodextrinecyclodextrine and citric acid) and citric acid)

Orgnic polymer made of polyacrylate, under industrial licence (ARKEMA)

Pb2+ Cd2+ Zn2+

430 288 205

Saturation capacity of D60 expressed in mg/g

- Cationic exchange capacity: 8.4 mmol g-1

- N°CAS : 9033-79-8- water absorption rate: (« tea bag » technic: 65g/g)- Apparent density: 0.75 g/cm3.

D60

MaterialsMaterials and and methodsmethods

(1) Martel, B.; Ruffin, D.; Weltrowski, M.; Lekchiri, Y.; Morcellet, M. J. Appl. Polym. Sci. 2005, 97, 433-442

Polymer made of cyclodextrine and citric acid

polyββββCD-CTR

10 min 120 min 10 min 120 min 10 min 120 min

76 % 85 % 77 % 100 % 50 % 100 %

Cationic exchange capacity : 4.3 mmol g-1

Cd2+ Pb2+ Zn2+

(2) Ducoroy, L.; Bacquet, M.; Martel, B.; Morcellet, M. Reactive & Functional polymers 2008, 68, 594-600

Percentages of metal absorbed at different time (pH = 5) [Me2+]t=0 = 100 mg L-1

Materials and methodsMaterials and methods

Materials and methodsMaterials and methods•• 2 Topsoils 2 Topsoils

•• Drying <40Drying <40°°CC

•• Grinding <Grinding <1010 mm mm

•• Soil homogeneisation (Soil homogeneisation (10 min)10 min)

•• Maturation for 6 months at 20 % humidity with tap water Maturation for 6 months at 20 % humidity with tap water (pH=7)(pH=7)

•• Pots of 3 LPots of 3 L

Incubation

IncubationBefore mixing

Homogeneisation After mixing

Materials and methodsMaterials and methods•• In vitroIn vitro Bioaccessibility test (following Bioaccessibility test (following

BARGE protocol)BARGE protocol)

Gastro-intestinal

extraction

+ 27 mL jus Duodenal+ 9 mL Bile

Centrifugation3000 g - 5 min

End-over-endrotation

4h00 - 37°C

Residual soil

..............Chyme

............

(pH = 6.3+_ 0.5)

Filtration 27µm(Whatman n°41)

Analysis AAS

............

0.6 g soil

............................................................ ........................

+ 9 mL Saliva

+ 13.5 mL Gastric juice pH = 1.2 - 1.7

....................................

(pH = 6.5+_ 0.5)

Manualshaking

5 - 15 min

Chyme

..........................Residual soil

1h00 - 37°C

End-over-endrotation

Centrifugation3000 g - 5 min

Gastric extraction

Filtration 27µm(Whatman n°41)

Analysis AAS

ResultsResults

•• Reference NIST 2710Reference NIST 2710

Total (mg kg-1)

(Ellickson et al., 2001) (Denys et al., 2007)(Oomen

et al.,2004)This study

Gastric Intestinal Gastric Intestinal Intestinal Gastric Intestinal

Cd 21,8 55-65 57,1 ±±±±2,8 27,2 ±±±± 8,3

Pb 5532 76,1 ± 11 10,7 ± 2,3 79 ± 4 25 ± 1 30-35 55 ±±±± 6,7 30,6 ±±±± 2,5

Zn 6952 20,5 ±±±± 3,8 11,1 ±±±± 1,2

ResultsResults

•• Difference between Difference between

bioaccessibility bioaccessibility

percentages of percentages of

amended over nonamended over non--

amended soils. amended soils.

Mean and SD Mean and SD

(n=6).(n=6).

-30

-20

-10

0

10

20

30

Cd

PbZn

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

Phosphate Fly ash D60 BCD-TCR

A

B

-30

-20

-10

0

10

20

30

-30

-20

-10

0

10

20

30

-30

-20

-10

0

10

20

30

Cd

PbZn

Cd

PbZn

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

Phosphate Fly ash D60 BCD-TCRPhosphate Fly ash D60 BCD-TCR

A

B Gastro-intestinal

Gastric

*

**

*

*

***

*

* Significant Wilcoxon paired t test

DiscussionDiscussion

•• Interesting effects of organic amendments Interesting effects of organic amendments

for the for the reductionreduction of gastroof gastro--intestinal intestinal

bioaccessibility of Cd, Pb and Zn in soils.bioaccessibility of Cd, Pb and Zn in soils.

•• Decrease of Decrease of 4 to 9 4 to 9 % of bioaccessibility.% of bioaccessibility.

•• High variation to be refine with more tests High variation to be refine with more tests

(including other compartments as plants, (including other compartments as plants,

animals, etc.).animals, etc.).

ConclusionConclusion

•• More work should be done on amendment More work should be done on amendment

effects and fine particles (<50 effects and fine particles (<50 µµm)m)

•• LongLong--term effects of all amendments and term effects of all amendments and

especially on polymers ?especially on polymers ?

•• Amendments and dust ?Amendments and dust ?

•• Tests on Eisenia and plants (Ray Grass Tests on Eisenia and plants (Ray Grass

and Clover)and Clover)

•• Thank you for your attention !Thank you for your attention !

Post Doctoral position Post Doctoral position

availableavailable

Oral bioavailability assessment Oral bioavailability assessment

of trace elements in soils and of trace elements in soils and

dust from an area heavily dust from an area heavily

contaminated by a former lead contaminated by a former lead

smeltersmelter