GARDEN SOIL AND HOUSE DUST AS EXPOSURE MEDIA FOR LEAD UPTAKE IN THE MINING

VILLAGE OF STRATONI, N GREECE

Argyraki, A., Plakaki, A. and Nicolaou, S.

SEGH 2008, Athens

National and Kapodistrian University of Athens, Faculty of Geology and Geoenvironment

LOCATION OF STUDY AREA

STRATONI

N

WIDER AREA – GEOLOGY & MINING

H.sc: Mining wastes n.q.: diorite porphyry ab: Amphibolite

Al: Alluvium gh: Granodiorite p: peridotite & dunite

Pt: Pleistocene mr1: Marble gn2: two-mica gneiss

Ir: Gossan gn.bi: Biotite gneiss (IGME, 1978, Gazea, 2004).

Stratoniki

Stratoni

MademLakkos mine

Mavres Petresmine

0 400200

Legendsoil samplesampling stratamining wastebuildingroadstreamseashore

N

Meters800

Ore Mill FactoryPb/Ag & Zn concentrates

Abandoned mine shaft

Mine tailings

AIM & OBJECTIVES

Characterisation of soil and house dust as exposure media for Pb uptake at Stratoni mining village.

Compare:

• Content of bulk samples

• Measurement and geochemical variability

• Speciation

METHODOLOGY

Geochemical Data

MineralogicalData

SpeciationGarden soil 0-5 cm

<100 µm (n = 38)

Total chemical analysis

Pb, Zn, Cu, Cd, Fe, Mn

Sequential extraction

(n = 10)

Heavy fraction

separation

AAS

XRD

SEM-EDS

PBET (n=10)

Vacuum cleaner

dust <75 µm(n = 30)

Geochemical/ measurement

variability

Sampling

sand62%

coarse silt4%

medium silt10%

fine silt18%

clay6%

SOIL GRAIN SIZE DISTRIBUTION

• Use of sampling and analytical duplicates for estimation of precision

p < ± 5% for Pb, Zn, Cu, Mn

Cd (± 30%) and Fe (± 14%)

- Sequential extraction: 5 duplicates

p = ± 2 - 20% for all elements- all stages

• Use of 3 NIST- CRMs & analysis of 9 previously analyzed soil samples from the wider area for estimation of analytical bias

- No statistically significant bias was found (p =0.05)

QUALITY CONTROL

Parameter Mean Median St. Dev. Min Max

SOIL (n= 38)

Pb 1090 1070 390 124 2042

Fe 45 700 45 103 9 205 23 786 73 767

Mn 4 465 2940 4 368 394 19 777

DUST (n= 30)

Pb 1830 990 1700 390 6920

Fe 24100 21700 11000 7710 59500

Mn 1380 1060 1060 506 5090

TOTAL CONCENTRATIONS (μg g-1)

00.20.40.60.8

11.21.41.61.8

2

Pb Fe Mn

D/SD/BGS/BG

TOTAL ANALYSIS CONCENTRATION RATIOS

D = dust conc. S = soil conc. BG = soil background (Kelepertsis et al., 2006)

cd_soil

zn_soil

mn_soil

pb_soil

Mn_dustfe_soil

cu_soil

Fe_dust

Cu_dust

Zn_dust

Cd_dust

Pb_dust

67.47

78.31

89.16

100.00

Similarity

Variables

TOTAL ANALYSIS VARIABLE CLUSTERING

ANALYSIS OF VARIANCE

Sample location

Sample 1

Analysis 1

Analysis 2

Sample2

Analysis 1

Analysis 2

ANALYSIS OF VARIANCE

geochem77.60%

sampling22.36%

analytical0.04%

Dust (n=7)10 m apart

Soil (n=13)5 m apart

geochem 96.11%

sampling3.86%

analytical 0.03%

analytical0%

sampling58%

geochem42%

Soil (n=9)10 m apart

Pb MAPS OF STRATONI

OPERATIONALLY DEFINED SPECIATION

• Five step sequential extraction on soil samples (Tessier et al., 1979; Li & Thornton, 2001)

• PBET on soil and dust samples (Ruby et al., 1996) using glycine –HCl solution at pH= 1.5, T= 37 oC

PARTITION (%) OF HEAVY METALS IN SOIL PHASES (n=10)

Pb Zn Cu Cd Fe Mn0%

20%

40%

60%

80%

100%V

IV

III

II

IExchangeable ions

Carbonate & specifically adsorbed

Fe/ Mn Oxides

Organic matter & sulphides

Silicates & slag

PBET RESULTS (n = 10)

0 500 1000 1500 2000 2500

G3

E7

G5-A

E4

K3

J6-B

D6

K4-A

K6

J3-1

Pb (mg /kg)

sam

ple

ID

DUSTSOIL

SOIL & DUST MINERALOGY

MINERAL SOIL DUSTQuartz + +Feldspar + +Mica + +Kaolinite + +Illite + +Calcite +Fe- Mn oxides + +Sulphides + +Secondary metal bearing minerals (e.g. pyromorphite, tsumcorite, corkite)

+

Slag + +

Pb BEARING SOIL GRAINS– SEM BSE

gn

Mn-Ox

qz

Fe-Ox

Pyromorphite

Slag (Pb-Fe-Si)

Pyromorphite

Fe Ox-Hydr(Pb-As)

Pb BEARING DUST GRAINS– SEM BSE

Fe- oxide

galena

galena

sphalerite

calcite

PbO

galena

calcite

CONCLUSIONS

•Successful combination of geochemical and mineralogical data for hazard characterization

• Dust samples enriched in Pb compared to soil dust enriched in fine grained sulphides

• Spatial trend of Pb concentrations observed in both media

• Lack of correlation between soil/ dust Pb + in vitro bio-accessibility estimated by PBET importance of house dust as Pb exposure medium in the area

• Comparison with Mn, Fe data effect of outdoors- indoors conditions on the fate of Pb

• Health impact assessment for “concerned stakeholders”?