Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

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Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood

Transcript of Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Page 1: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Bernine KhanUniversity of Miami

Arsenic Speciation of New & WeatheredCCA-Treated Wood

Page 2: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• Purpose

• Basic Arsenic Chemistry

• Solvent-Extraction Leaching Expts

• Arsenic Analysis of GW at Florida C&D Landfills

• Arsenic Leaching from Lysimeter Study

• Arsenic Leaching from CCA-Treated Deck

Arsenic Study Outline

Page 3: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Study Outline

• Purpose

• Basic Arsenic Chemistry

• Solvent-Extraction Leaching Expts

• Arsenic Analysis of GW at Florida C&D Landfills

• Arsenic Leaching from Lysimeter Study

• Arsenic Leaching from CCA-Treated Deck

Page 4: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Study Outline

• Purpose

• Basic Arsenic Chemistry

• Solvent-Extraction Leaching Expts

• Arsenic Analysis of GW at Florida C&D Landfills

• Arsenic Leaching from Lysimeter Study

• Arsenic Leaching from CCA-Treated Deck

Page 5: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Study Outline

• Purpose

• Basic Arsenic Chemistry

• Solvent-Extraction Leaching Expts

• Arsenic Analysis of GW at Florida C&D Landfills

• Arsenic Leaching from Lysimeter Study

• Arsenic Leaching from CCA-Treated Deck

Page 6: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Study Outline

• Purpose

• Basic Arsenic Chemistry

• Solvent-Extraction Leaching Expts

• Arsenic Analysis of GW at Florida C&D Landfills

• As Leaching - Lysimeter Study (Jenna - UF)

• Arsenic Leaching from CCA-Treated Deck

Page 7: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Study Outline

• Purpose

• Basic Arsenic Chemistry

• Solvent-Extraction Leaching Expts

• Arsenic Analysis of GW at Florida C&D Landfills

• Arsenic Leaching from Lysimeter Study

• Arsenic Leaching from a constructed

CCA-Treated Deck

Page 8: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• Identify & quantify arsenic species leaching from CCA-treated wood

• Arsenic toxicity varies with each species

• To study the migration of arsenic species [As(III) & As(V)] in soils

• Estimate the impact of arsenic leaching from in-service & disposed CCA-treated wood on groundwater

Purpose of Study

Page 9: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• Identify & quantify arsenic species leaching from CCA-treated wood

• Arsenic toxicity varies with each species

• To study the migration of arsenic species [As(III) & As(V)] in soils

• Estimate the impact of arsenic leaching from in-service & disposed CCA-treated wood on groundwater

Purpose of Study

Page 10: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• Identify & quantify arsenic species leaching from CCA-treated wood

• Arsenic toxicity varies with each species

• To study the migration of arsenic species [As(III) & As(V)] in soils

• Estimate the impact of arsenic leaching from in-service & disposed CCA-treated wood on groundwater

Purpose of Study

Page 11: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• Identify & quantify arsenic species leaching from CCA-treated wood

• Arsenic toxicity varies with each species

• To study the migration of arsenic species [As(III) & As(V)] in soils

• Estimate the impact of arsenic leaching from in-service & disposed CCA-treated wood on groundwater

Purpose of Study

Page 12: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• The individual parts that make up the whole:

What is Speciation?

Element valence

Particle size

Molecular weight size

Inorganic & organic form

Page 13: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• The individual parts that make up the whole:

What is Speciation?

Element valence

Particle size

Molecular weight size

Inorganic & organic form

Page 14: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• The individual parts that make up the whole:

What is Speciation?

Element valence

Particle size

Molecular weight size

Inorganic & organic form

Page 15: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• The individual parts that make up the whole:

What is Speciation?

Element valence

Particle size

Molecular weight size (Sheena - FIU)

Inorganic & organic form

Page 16: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• The individual parts that make up the whole:

What is Speciation?

Element valence

Particle size

Molecular weight size

Inorganic & organic form

Page 17: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Speciation

Arsenic

As(III) As(V) MMAA DMAA

Various forms of an element that make up the total concentration of that element

Inorganic Organic

-3 0 +1 +3 +5Valence

InorganicArsine (g)

Page 18: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic

As(III) As(V) MMAA DMAA

Various forms of an element that make up the total concentration of that element

Inorganic Organic

-3 0 +1 +3 +5Valence

InorganicArsine (g)

Speciation

Page 19: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic

As(III) As(V) MMAA DMAA

Various forms of an element that make up the total concentration of that element

Inorganic Organic

-3 0 +1 +3 +5Valence

InorganicArsine (g)

Speciation

Page 20: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• In nature – arsenites (As(III)) & arsenates (As(V))

• Soluble arsenic compounds

• As(III) - more soluble in water & body fluids

• Toxicity

Interest in Speciation

Page 21: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• In nature – arsenites (As(III)) & arsenates (As(V))

• Soluble arsenic compounds (As(III)) are more toxic to humans than insoluble

• As(III) - more soluble in water & body fluids

• Toxicity

Interest in Speciation

Page 22: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• In nature – arsenites (As(III)) & arsenates (As(V))

• Soluble arsenic compounds are more toxic to humans than insoluble

• As(III) compounds are generally more soluble in water & body fluids

– not excreted readily– accumulates in body– toxic at low concentrations

• Toxicity

Interest in Speciation

Page 23: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

• In nature – arsenites (As(III)) & arsenates (As(V))

• Soluble arsenic more toxic to humans

• As(III) - more soluble in water & body fluids

• Toxicity is dependent upon: -arsenic compound-magnitude of exposure (conc. accumulated over time)

- species

Interest in Speciation

Page 24: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Toxicity of Arsenic Species Dependent on chemical form

• AsH3 - arsine (gas) – most toxic (formed under reduced conditions)

• As(III) - arsenite

• As(V) - arsenate

• MMAA - monomethylarsonic acid

• DMAA - dimethylarsinic acid

• TMAO - trimethylarsine oxide

• AsB - arsenobetaine (marine) *

• AsC - arsenocholine (marine) *

Page 25: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Toxicity of Arsenic Species Dependent on chemical form

• AsH3 - arsine (gas)

• As(III) - arsenite – inorganic (more toxic)

• As(V) - arsenate – inorganic - CCA

• MMAA - monomethylarsonic acid

• DMAA - dimethylarsinic acid

• TMAO - trimethylarsine oxide

• AsB - arsenobetaine (marine) *

• AsC - arsenocholine (marine) *

Page 26: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Toxicity of Arsenic Species Dependent on chemical form

• AsH3 - arsine (gas)

• As(III) - arsenite – inorganic

• As(V) - arsenate – inorganic

• MMAA - monomethylarsonic acid

• DMAA - dimethylarsinic acid

• TMAO - trimethylarsine oxide

• AsB - arsenobetaine (marine) *

• AsC - arsenocholine (marine) *

bacteria

Page 27: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Toxicity of Arsenic Species Dependent on chemical form

• AsH3 - arsine (gas)

• As(III) - arsenite – inorganic

• As(V) - arsenate – inorganic

• MMAA - monomethylarsonic acid

• DMAA - dimethylarsinic acid

• TMAO - trimethylarsine oxide

• AsB - arsenobetaine (marine) *

• AsC - arsenocholine (marine) *

Page 28: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Leaching FromCCA-Treated Wood

Solvent-Extraction Tests

• Toxicity Characteristic Leaching Procedure (TCLP) – EPA’s standardized leaching test to determine if treated wood waste is hazardous. CCA-treated wood carries an exemption.

• SPLP – EPA’s leaching test

• Other Solvents

• pH Stat – Leaching of As species under different pH conditions (similar to TCLP)

Page 29: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Leaching FromCCA-Treated Wood

Solvent-Extraction Tests

• TCLP – EPA’s leaching test

• Synthetic Precipitation Leaching Procedure (SPLP) – EPA’s standardized leaching test to (simulate rainfall) determine if treated wood waste should be land applied

• Other Solvents

• pH Stat – Leaching of As species under different pH conditions (similar to TCLP)

Page 30: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Leaching FromCCA-Treated Wood

Solvent-Extraction Tests

• TCLP – EPA’s leaching test

• SPLP – EPA’s leaching test

• Other Solvents – Deionized Water, Rainwater, & Seawater

• pH Stat – Leaching of As species under different pH conditions (similar to TCLP)

Page 31: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Arsenic Leaching FromCCA-Treated Wood

Solvent-Extraction Tests

• TCLP – EPA’s leaching test

• SPLP – EPA’s leaching test

• Other Solvents – Deionized Water, Rainwater, & Seawater

• pH Stat – Leaching of As species under different pH conditions (similar to TCLP)

Page 32: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

CCA-treated wood subjected to leaching solvent, rotated for 18 2 hrs & filtered. Filtrate analyzed for arsenic species

New CCA-treated

wood

TCLP

SPLP

DI Water

Rainwater

Untreated0.25 pcf0.6 pcf2.5 pcf

WeatheredCCA-treated

wood

PlaygroundUtility pole

FenceC&D waste

Solvent-Extraction of CCA-Treated Wood

Page 33: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

CCA-treated wood subjected to leaching solvent, rotated for 18 2 hrs & filtered. Filtrate analyzed for arsenic species

New CCA-treated

wood

TCLP

SPLP

DI Water

Rainwater

Untreated0.25 pcf0.6 pcf2.5 pcf

WeatheredCCA-treated

wood

Solvent-Extraction of CCA-Treated Wood

PlaygroundUtility pole

FenceC&D waste

Page 34: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

TCLP ResultsNew & Weathered Wood

Is treated wood waste hazardous?(Acetic Acid)

0

2

4

6

8

10

A B G J M T V

Con

cent

ratio

n (m

g/L

)

As(III)As(V)Total As

TCLP 5 mg/L

New Weathered

T V

Page 35: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

SPLP Results New & Weathered Wood

Should treated wood waste be land applied?(Sulphuric Acid/Nitric Acid)

SPLP 0.05 mg/L

As(III)As(V)Total As

0

2

4

6

8

10

12

A B C D E F G H I J K L M N O P Q R S T V

Co

nce

ntr

ati

on

(m

g/L

)

New Weathered

T V

Page 36: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Deionized Water New & Weathered Wood

As(III)As(V)Total As

TCLP 5 mg/L

0

1

2

3

4

5

6

A B G J M T U

Con

cen

trat

ion

(m

g/L

)

New Weathered

T U

Page 37: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Rainwater Results New & Weathered Wood

TCLP 5 mg/L

0

2

4

6

8

10

12

14

A B G J M N O P Q R S T U

Con

cent

rati

on (m

g/L

)

As(III)As(V)Total As

New Weathered

T U

Page 38: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Results of TCLP & SPLPNew & Weathered Wood Ash

0

50

100

150

200

250

300

350

A B G J M T V

Con

cent

ratio

n (m

g/L

)

TCLP 5 mg/L

As(III)As(V)

As(III)As(V)

TCLP

SPLP

New Weathered

T V

Page 39: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

pH Stat

• CCA-treated wood subjected to leaching solvent (HNO3 or NaOH – to obtain desired pH)

New (0.4 pcf) CCA-treated woodmeasured at 0.214 pcf

pH 123456789

101112

Weathered CCA-treated woodmeasured at 0.386 pcf

Page 40: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Results of pH StatNew Wood

0

10

20

30

40

50

1 2 3 4 5 6 7 8 9 10 11 12 13

pH

Conce

ntr

atio

n (m

g/L)

• As(V) was the only specie detected• Highest concentration at extreme pH • Environmental pH range – As(V) ~ 5mg/L

TCLP 5 mg/L

Environmental pH

Page 41: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Results of pH StatWeathered Wood

• Both As(III) & As(V) detected • As(III) up to pH 8.5• Environmental pH range – Total As increase

Total As > 5 mg/L

TCLP 5 mg/L0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12

pH

Con

cen

trati

on

(mg/L

) As(III)As(V)TotalEnvironmental

pH

Page 42: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Results of pH Stat Total Arsenic

0

10

20

30

40

50

1 2 3 4 5 6 7 8 9 10 11 12 13pH

Tota

l ars

enic

conc.

(mg/L

)

New (0.214 pcf)Weathered (0.386 pcf) – 14 yrs

TCLP 5 mg/L

Environmental pH

Page 43: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Summary

•As(III) present in all wood – new & weathered.

• If CCA-treated wood did not carry the exemption – it would fail TCLP and be categorized as hazardous waste

•All new & weathered CCA-treated wood failed the SPLP

•Slightly more As leaching from rainwater than the SPLP (simulate rainwater)

Page 44: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Summary

•As(III) present in all wood – both new & weathered

• If CCA-treated wood did not carry the exemption – it would fail TCLP and be categorized as hazardous waste

•All new & weathered CCA-treated wood failed the SPLP

•Slightly more As leaching from rainwater than the SPLP (simulate rainwater)

Page 45: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Summary

•As(III) present in all wood – both new & weathered

• If CCA-treated wood did not carry the exemption – it would fail TCLP and be categorized as hazardous waste

•All new & weathered CCA-treated wood failed the SPLP

•Slightly more As leaching from rainwater than the SPLP (simulate rainwater)

Page 46: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Summary

•As(III) present in all wood – both new & weathered

• If CCA-treated wood did not carry the exemption – it would fail TCLP and be categorized as hazardous waste

•All new & weathered CCA-treated wood failed the SPLP

•Slightly more As leaching from rainwater than the SPLP (simulate rainwater)

Page 47: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

•CCA-treated wood should not be incinerated and dispose to MSW and C&D landfills or land applied

•As leaching is pH dependent

•As species leaching pH dependent

•At environmental pH range (6-10) – As ~ 5mg/L

•More As leaching from weathered wood than new

Summary

Page 48: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

•CCA-treated wood should not be incinerated and dispose to landfills or land applied

•Total As leaching is pH dependent

•As species leaching pH dependent

•At environmental pH range (6-10) – As ~ 5mg/L

•More As leaching from weathered wood than new

Summary

Page 49: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

•CCA-treated wood should not be incinerated and dispose to landfills or land applied

•As leaching is pH dependent

•As species leaching pH dependent

•At environmental pH range (6-10) – As ~ 5mg/L

•More As leaching from weathered wood than new

Summary

Page 50: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

•CCA-treated wood should not be incinerated and dispose to landfills or land applied

•As leaching is pH dependent

•As species leaching pH dependent

•At environmental pH range (6-10) – As ~ 5mg/L

•More As leaching from weathered wood than new

Summary

Page 51: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

•CCA-treated wood should not be incinerated and dispose to landfills or land applied

•As leaching is pH dependent

•As species leaching pH dependent

•At environmental pH range (6-10) – As ~ 5mg/L

•Overall, more As leaching from weathered wood than new

Summary

Page 52: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

??Questions?

Page 53: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Lysimeter StudyLysimeter 1 – Untreated Wood

0

0.005

0.01

0.015

0.02

Aug.6

Aug.21

Sept.6

Oct.14

Nov.18

Dec. 2

Con

cen

trat

ion

(m

g/L

)

As(III)As(V)DMAAMMAA

Page 54: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Lysimeter StudyLysimeter 2 – CCA-Treated Wood

(50% New & 50% Used

As(III)As(V)DMAAMMAA

• Predominantly As(III) & As(V)• Low organoarsenic species concentrations

05

1015202530354045

Jan. 2

8

Jun. 1

2

Jun. 2

5

Aug. 6

Sept.

6

Oct

. 14

Dec. 2

Con

cen

trat

ion

(m

g/L

)

Page 55: Bernine Khan University of Miami Arsenic Speciation of New & Weathered CCA-Treated Wood.

Lysimeter StudyLysimeter 3 – Typical C&D Mix

As(III)As(V)DMAAMMAA

• All species detected

0

0.005

0.01

0.015

0.02

0.025

0.03

Jun.25

Aug. 6

Aug.21

Sept.6

Sept.25

Oct.14

Nov.18

Dec.2

Con

cen

trat

ion

(m

g/L

)