GARDEN SOIL AND HOUSE DUST AS EXPOSURE MEDIA FOR …
Transcript of GARDEN SOIL AND HOUSE DUST AS EXPOSURE MEDIA FOR …
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”?