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Bernine Khan University of Miami

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

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Bernine Khan University of Miami

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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

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

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

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

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

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

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

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

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

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

  21. 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

  22. 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

  23. 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

  24. Toxicity of Arsenic SpeciesDependent 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) *

  25. Toxicity of Arsenic SpeciesDependent 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) *

  26. Toxicity of Arsenic SpeciesDependent 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

  27. Toxicity of Arsenic SpeciesDependent 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) *

  28. 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)

  29. 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)

  30. 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)

  31. 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)

  32. Solvent-Extraction of CCA-Treated Wood CCA-treated wood subjected to leaching solvent, rotated for 18  2 hrs & filtered. Filtrate analyzed for arsenic species Untreated 0.25 pcf 0.6 pcf 2.5 pcf TCLP New CCA-treated wood SPLP DI Water Playground Utility pole Fence C&D waste Weathered CCA-treated wood Rainwater

  33. Solvent-Extraction of CCA-Treated Wood CCA-treated wood subjected to leaching solvent, rotated for 18  2 hrs & filtered. Filtrate analyzed for arsenic species Untreated 0.25 pcf 0.6 pcf 2.5 pcf TCLP New CCA-treated wood SPLP DI Water Playground Utility pole Fence C&D waste Weathered CCA-treated wood Rainwater

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

  35. SPLP Results New & Weathered Wood Should treated wood waste be land applied? (Sulphuric Acid/Nitric Acid) New Weathered As(III) As(V) Total As SPLP 0.05 mg/L T V

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

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

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

  39. pH Stat • CCA-treated wood subjected to leaching solvent (HNO3 or NaOH – to obtain desired pH) pH 1 2 3 4 5 6 7 8 9 10 11 12 New (0.4 pcf) CCA-treated wood measured at 0.214 pcf Weathered CCA-treated wood measured at 0.386 pcf

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

  41. Results of pH Stat Weathered Wood As(III) As(V) Total Environmental pH TCLP 5 mg/L • Both As(III) & As(V) detected • As(III) up to pH 8.5 • Environmental pH range – Total As increase • Total As > 5 mg/L

  42. New (0.214 pcf) Weathered (0.386 pcf) – 14 yrs Results of pH Stat Total Arsenic Environmental pH Total arsenic conc. (mg/L) TCLP 5 mg/L

  43. 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)

  44. 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)

  45. 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)

  46. 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)

  47. Summary • 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

  48. 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

  49. 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

  50. 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

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