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KKdd values of Cu, Cr, As in dif values of Cu, Cr, As in different soil matrix ferent soil matrix
1Sung-Mo Kang, 2Seung-Hun Shin, 1Ja-Oon Koo
(1Korea Forest Research Institute, 2Dong-Yang Timber Co., LTD)
● Preservative treated wood
Purpose
- Extend service life
- Improve economic values
- Protect forest
● CCA consumption in Korea
050
100150200250300350400450500
Consu
mption
(ton)
2000 2001 2004 2005
Year
● Biocide use in Korea
95%
5%
94%
6%
82%
18%
0%10%20%30%40%50%60%70%80%90%
100%
2000 2005 2006.6.
AlternativesCCA
ACQCUAZ
CB-HDO
● Toxicity of CCA
1. AS2O5 & Cr+6 Poisonous
2. Respiratory disease, carcinogen, ulcer, skin irritation
LD50
(mg/kg)LC50
(96hr)Carcinogen
As rat 15~293 fish 64mg/L ○
Cr rat 149~177 Trout 69mg/L ○
(UNEP, 1994)
● CCA debate
Chemical fixation of CCA with wood component results in environmentally safe products.
Treated wood will be eventually degraded and cause environment pollution.
Soil pollution standards and soil remediation criteria in Korea.
Cu
Soil pollutionAgricultural : 6mg/kg
Commercial/Industrial : 20mg/kg
Soil remediationAgricultural : 15mg/kg
Commercial/Industrial : 50mg/kg
As
Soil pollution Agricultural : 50mg/kg
Commercial/Industrial : 200mg/kg
Soil remediationAgricultural : 125mg/kg
Commercial/Industrial : 500mg/kg
Component
Criteria
Cr
Soil pollution
Cr6+(Agricultural) : 4mg/kg
Cr6+(Commercial/Industrial ) : 12mg/kg
Soil remediationCr6+(Agricultural A area) : 10mg/kg
Cr6+(Commercial/Industrial ) : 30mg/kg
● Ban components of CCA
Ban CCA treated wood (Ministry of Environment Notice 2007-162) <2007.10.8.>
Voluntarily stop use CCA by Korea preservative industry <2006.Novemver>
Mobility and retention of chromium, copper, and arsenic leached from In-service CCA-treated wood in soil
Mobility and retention of chromium, copper, and arsenic leached from In-service CCA-treated wood in soil
Figure 1. Soil sampling methods
Figure 2. Cr, Cu and As levels in soil at selected distances.
0
10
20
30
40
50
60
70
0 20 40 60 80 100 120 140
Distance(cm)
Conc.(
ppm
)
Cr Cu As
Mobility and retention of chromium, copper, and arsenic leached from In-service CCA-treated wood in soil
Figure 3. Cr, Cu and As levels in soil at selected depths.
0
10
20
30
40
50
60
70
80
90
100
110
120
0 10 20 30 40 50 60 70 80 90 100
Conc.(ppm)
Depth
(cm
)
Cr Cu As
Mobility and retention of chromium, copper, and arsenic leached from In-service CCA-treated wood in soil
Mobility and retention of chromium, copper, and arsenic leached from In-service CCA-treated wood in soil
Physical characteristics of tested soils.
SampleSand(%)
Silt(%)
Clay(%)
Soiltexture
Bulk density(g/ml)
Porosity
Sandy loam 62.0 27.4 10.6 SL 1.57 0.47
Sand 93.4 3.4 3.2 S 1.67 0.34
Figure 4. Cr, Cu and As levels in two different soils.
Mobility and retention of chromium, copper, and arsenic leached from In-service CCA-treated wood in soil
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Cu Cr As
pp
mSandy soil
Sandy loam
● Partition Partition CoefficientsCoefficients
Kow = C oct/C waterKow = C oct/C water
Kom = C organic matter/C waterKom = C organic matter/C water
Koc = C organic carbon/C waterKoc = C organic carbon/C water
Kd = C solid/C waterKd = C solid/C water
● Kd (soil-water partition coefficient)
Csoil = Conc. absorbed to soil matrix
Cwater = Conc. in water
Cs
Cw
(ml/g)=
● Kd (soil-water partition coefficient)
High KdHigh Kd
Low water solubilityLow water solubility
Low biodegradationLow biodegradation
Remain in soilRemain in soil
Cr Cu As
Kd(ml/g) 850 35 200
Values of the soil-water partition coefficient kd (Baes and Sharp, 1983; Baes et al, 1984; EPA, 1999; EPA 2005).
DDT : 2,380ml/g Benzene : 0.198ml/g
● Kd (soil-water partition coefficient)
● Objective
To measure adsorption To measure adsorption characteristics of domestic soils characteristics of domestic soils for chromium, copper, and for chromium, copper, and arsenic. arsenic.
Physical and chemical characteristics
of tested soils
Soil texture , pH, Organic Matter (%)
Bulk density, Porosity, Cation exchange capacity exchangeable cations
● Materials and Methods
● Materials and Methods
4 different types of soil matrix [Soil, Soil:OM (8:2) Soil:OM (1:1) OM]
Sorption affinities (ASTM D4646-87)
- Standard solutions (Kanto chemical)
- Flame atomic absorption spectrometer (Shi
madzu AA-6800) - Distribution coefficient (Kd)
● Materials and Methods
SHIMADZU AA-6800
HVG
HYDRIDE VAPOR GENERATOR
Physical characteristics of tested soils.
SampleSand(%)
Silt(%)
Clay(%)
Soiltexture
Bulk density(g/ml)
Porosity
Soil 62.0 27.4 10.6 SL 1.57 0.47
● Results and Discussion
Chemical characteristics of tested soils.
● Results and Discussion
SamplepH
(H2O)Organic Matter
(%)Total Nitrogen
(%)P2O5
(mg/kg)
Soil 5.9 1.8 0.08 108
CEC, exchangeable cations and base satu
ration of tested soils.
● Results and Discussion
SampleCEC
(cmol+/kg)
Exchangeable cations(cmol+/kg) Base
saturation(%)K+ Na+ Ca2+ Mg2+ Sum of
bases
Soil 8.14 0.41 0.09 0.60 0.45 1.55 19.04
● Results and Discussion
0
500
1000
1500
2000
2500
Soil 8:2(S:OM) 1:1(S:OM) OM
Cr
As
CuKd
Figure 5. Values of Kd for three metals in different soilValues of Kd for three metals in different soil matrixmatrix.
● Conclusions
1. Values of the distribution coefficient (Kd) 1. Values of the distribution coefficient (Kd) Chromium > Arsenic > Copper in all 4 matrix. Chromium > Arsenic > Copper in all 4 matrix.
2. Different soil matrixes resulted in varying 2. Different soil matrixes resulted in varying mobilities of CCA components. mobilities of CCA components.
3. The values of Kd for all three metals were 3. The values of Kd for all three metals were lower in the soil without organic matter, lower in the soil without organic matter, but increased with organic matter contents. but increased with organic matter contents.
● Conclusions
4. Further studies will be necessary 4. Further studies will be necessary to explain leaching behavior at different soilto explain leaching behavior at different soil characteristics.characteristics.
5. The mobility of metal components may be very5. The mobility of metal components may be very limited to the surface area adjacent to CCA-limited to the surface area adjacent to CCA- treated wood due to their fairly large Kd. treated wood due to their fairly large Kd.
6. The metal components would be persistent6. The metal components would be persistent and accumulated in the soil, resulting in highand accumulated in the soil, resulting in high chemical concentration in service area ofchemical concentration in service area of treated wood. treated wood.
