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
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 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 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
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
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
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
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
The individual parts that make up the whole: What is Speciation? Element valence Particle size Molecular weight size Inorganic & organic form
The individual parts that make up the whole: What is Speciation? Element valence Particle size Molecular weight size Inorganic & organic form
The individual parts that make up the whole: What is Speciation? Element valence Particle size Molecular weight size Inorganic & organic form
The individual parts that make up the whole: What is Speciation? Element valence Particle size Molecular weight size (Sheena - FIU) Inorganic & organic form
The individual parts that make up the whole: What is Speciation? Element valence Particle size Molecular weight size Inorganic & organic form
Speciation Arsenic As(III) As(V)MMAADMAA Various forms of an element that make up the total concentration of that element Inorganic Organic Valence Inorganic Arsine (g)
Arsenic As(III) As(V)MMAADMAA Various forms of an element that make up the total concentration of that element Inorganic Organic Valence Inorganic Arsine (g) Speciation
Arsenic As(III) As(V)MMAADMAA Various forms of an element that make up the total concentration of that element Inorganic Organic Valence Inorganic Arsine (g) 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 Interest in Speciation
Toxicity of Arsenic Species Dependent on chemical form AsH 3 - 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) *
Toxicity of Arsenic Species Dependent on chemical form AsH 3 - 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) *
Toxicity of Arsenic Species Dependent on chemical form AsH 3 - 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
Toxicity of Arsenic Species Dependent on chemical form AsH 3 - 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) *
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 pH Stat – Leaching of As species under different pH 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 pH Stat – Leaching of As species under different pH 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 pH Stat – Leaching of As species under different pH 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 pH Stat – Leaching of As species under different pH conditions (similar to TCLP)
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 Untreated 0.25 pcf 0.6 pcf 2.5 pcf Weathered CCA-treated wood Playground Utility pole Fence C&D waste 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 TCLP SPLP DI Water Rainwater Untreated 0.25 pcf 0.6 pcf 2.5 pcf Weathered CCA-treated wood Solvent-Extraction of CCA-Treated Wood Playground Utility pole Fence C&D waste
TCLP Results New & Weathered Wood Is treated wood waste hazardous? (Acetic Acid) As(III) As(V) Total As TCLP 5 mg/L New Weathered T V
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 New Weathered T V
Deionized Water New & Weathered Wood As(III) As(V) Total As TCLP 5 mg/L New Weathered TU
Rainwater Results New & Weathered Wood TCLP 5 mg/L As(III) As(V) Total As New Weathered T U
Results of TCLP & SPLP New & Weathered Wood Ash TCLP 5 mg/L As(III) As(V) As(III) As(V) TCLP SPLP New Weathered TV
pH Stat CCA-treated wood subjected to leaching solvent (HNO 3 or NaOH – to obtain desired pH) New (0.4 pcf) CCA-treated wood measured at pcf pH Weathered CCA-treated wood measured at pcf
Results of pH Stat New Wood 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
Results of pH Stat Weathered 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/L As(III) As(V) Total Environmental pH
Results of pH Stat Total Arsenic Total arsenic conc. (mg/L) New (0.214 pcf) Weathered (0.386 pcf) – 14 yrs TCLP 5 mg/L Environmental pH
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)
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 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 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)
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
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
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
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
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
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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