Arsenic Speciation of New Weathered CCATreated Wood Bernine

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

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

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

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

Purpose of Study • 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

What is Speciation? • The individual parts that make up the whole: Element valence Particle size Molecular weight size Inorganic & organic form

What is Speciation? • The individual parts that make up the whole: Element valence Particle size Molecular weight size (Sheena - FIU) Inorganic & organic form

What is Speciation? • The individual parts that make up the whole: Element valence Particle size Molecular weight size Inorganic & organic form

Speciation Arsenic Valence Arsine (g) -3 0 +1 +3 Inorganic As(III) As(V) +5 Organic MMAA DMAA Various forms of an element that make up the total concentration of that element

Interest in Speciation • In nature – arsenites (As(III)) & arsenates (As(V)) • Soluble arsenic compounds • As(III) - more soluble in water & body fluids • Toxicity

Interest in Speciation • 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 • 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 • • 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

Toxicity of Arsenic Species Dependent on chemical form • As. H 3 - arsine (gas) – most toxic (formed under reduced conditions) • • As(III) - arsenite As(V) - arsenate MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine) * As. C - arsenocholine (marine) *

Toxicity of Arsenic Species Dependent on chemical form • • As. H 3 - arsine (gas) As(III) - arsenite – inorganic (more toxic) As(V) - arsenate – inorganic - CCA MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine) * As. C - arsenocholine (marine) *

Toxicity of Arsenic Species Dependent on chemical form • • As. H 3 - arsine (gas) As(III) - arsenite – inorganic As(V) - arsenate – inorganic MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine) * As. C - arsenocholine (marine) * bacteria

Toxicity of Arsenic Species Dependent on chemical form • • As. H 3 - arsine (gas) As(III) - arsenite – inorganic As(V) - arsenate – inorganic MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide As. B - arsenobetaine (marine) * As. C - arsenocholine (marine) *

Arsenic Leaching From CCA-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 • p. H Stat – Leaching of As species under different p. H conditions (similar to TCLP)

Arsenic Leaching From CCA-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 • p. H Stat – Leaching of As species under different p. H conditions (similar to TCLP)

Arsenic Leaching From CCA-Treated Wood Solvent-Extraction Tests • TCLP – EPA’s leaching test • SPLP – EPA’s leaching test • Other Solvents – Deionized Water, Rainwater, & Seawater • p. H Stat – Leaching of As species under different p. H conditions (similar to TCLP)

Solvent-Extraction of 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 Untreated 0. 25 pcf 0. 6 pcf 2. 5 pcf TCLP Weathered CCA-treated wood Playground Utility pole Fence C&D waste DI Water SPLP Rainwater

TCLP Results New & Weathered Wood Is treated wood waste hazardous? (Acetic Acid) New Weathered TCLP 5 mg/L As(III) As(V) Total As T V

SPLP Results New & Weathered Wood Should treated wood waste be land applied? (Sulphuric Acid/Nitric Acid) New As(III) As(V) Total As Weathered T V SPLP 0. 05 mg/L

Deionized Water New & Weathered Wood New Weathered TCLP 5 mg/L As(III) As(V) Total As T U

Rainwater Results New & Weathered Wood New As(III) As(V) Total As Weathered TCLP 5 mg/L T U

Results of TCLP & SPLP New & Weathered Wood Ash New Weathered TCLP As(III) As(V) SPLP As(III) As(V) TCLP 5 mg/L T V

p. H Stat • CCA-treated wood subjected to leaching solvent (HNO 3 or Na. OH – to obtain desired p. H) p. H New (0. 4 pcf) CCA-treated wood measured at 0. 214 pcf Weathered CCA-treated wood measured at 0. 386 pcf 1 2 3 4 5 6 7 8 9 10 11 12

Results of p. H Stat New Wood Environmental p. H TCLP 5 mg/L • • • As(V) was the only specie detected Highest concentration at extreme p. H Environmental p. H range – As(V) ~ 5 mg/L

Results of p. H Stat Weathered Wood Environmental As(III) As(V) Total p. H TCLP 5 mg/L • • • Both As(III) & As(V) detected As(III) up to p. H 8. 5 Environmental p. H range – Total As increase Total As > 5 mg/L

Results of p. H Stat Total Arsenic Total arsenic conc. (mg/L) New (0. 214 pcf) Weathered (0. 386 pcf) – 14 yrs Environmental p. H TCLP 5 mg/L

Summary • • As(III) present in all wood – new & weathered. • All new & weathered CCA-treated wood failed the SPLP • Slightly more As leaching from rainwater than the SPLP (simulate rainwater) If CCA-treated wood did not carry the exemption – it would fail TCLP and be categorized as hazardous waste

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)

Summary • CCA-treated wood should not be incinerated and dispose to MSW and C&D landfills or land applied • • As leaching is p. H dependent As species leaching p. H dependent At environmental p. H range (6 -10) – As ~ 5 mg/L More As leaching from weathered wood than new

Summary • CCA-treated wood should not be incinerated and dispose to landfills or land applied • • Total As leaching is p. H dependent As species leaching p. H dependent At environmental p. H range (6 -10) – As ~ 5 mg/L More As leaching from weathered wood than new

Summary • CCA-treated wood should not be incinerated and dispose to landfills or land applied • • As leaching is p. H dependent As species leaching p. H dependent At environmental p. H range (6 -10) – As ~ 5 mg/L More As leaching from weathered wood than new

Summary • CCA-treated wood should not be incinerated and dispose to landfills or land applied • • As leaching is p. H dependent As species leaching p. H dependent At environmental p. H range (6 -10) – As ~ 5 mg/L Overall, more As leaching from weathered wood than new

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Lysimeter Study Lysimeter 1 – Untreated Wood As(III) As(V) DMAA MMAA

Lysimeter Study Lysimeter 2 – CCA-Treated Wood (50% New & 50% Used As(III) As(V) DMAA MMAA • • Predominantly As(III) & As(V) Low organoarsenic species concentrations

Lysimeter Study Lysimeter 3 – Typical C&D Mix As(III) As(V) DMAA MMAA • All species detected