1. As and Cr Speciation of New & Weathered CCA-Treated Wood

2. Purpose Basic As and Cr Chemistry Solvent-Extraction Leaching Experiments (Cr & As) As Analysis of GW at Florida C&D Landfills As Leaching from Lysimeters Outline

3. Quantify As & Cr species in leachates from CCA-treated wood As & Cr toxicity varies with each specie As & Cr mobility varies with each specie Estimate the impact of As & Cr leaching from in-service & disposed CCA-treated wood on groundwater Purpose & Motivation of Study

4. As Speciation Arsenic As(III) As(V)MMAADMAA Inorganic Organic -30+1+3+5 Valence Inorganic Arsine (g)

5. Arsenic As(III) As(V)MMAADMAA Inorganic Organic -30+1+3+5 Valence Inorganic Arsine (g) As Speciation Toxicity & Mobility

6. Arsenic As(III) As(V)MMAADMAA Inorganic Organic -30+1+3+5 Valence Inorganic Arsine (g) As Speciation Toxicity & Mobility

7. Cr Speciation Chromium Cr(VI)Cr(III) Inorganic 0+3+6 Valence Inorganic Cr Speciation Toxicity & Mobility

8. Analytical Methods for Speciation As: HPLC-ICP-MS or HPLC-HG-AFS Cr: IC for Cr(VI) Total Cr by ICP-AES Cr(III) by difference

9. Solvent Extraction Study

10. CCA-treated wood subjected to leaching solvent, rotated for 18  2 hrs & filtered. Filtrate analyzed for As & Cr 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 pH 1,2,3. etc..

11. pH Experiment - New Wood (0.32 pcf) As(V) was the only specie detected Highest concentration at extreme pH Environmental pH range ~ 5mg/L Total As (As(V)) – HPLC-HG-AFS Total As – ICP-AES Environmental pH

12. pH Experiment - Weathered Wood (0.41 pcf) As(III) & As(V) detected, As(III) up to pH 9.5 Environmental pH range – Total As increase Total As > 5 mg/L 0 5 10 15 20 25 30 35 40 45 1.272.563.724.155.165.416.548.049.43 10.1910.6811.9112.76 pH Arsenic Concentration (mg/L) Environmental pH As(III) As(V) Total As - HPLC-HG-AFS Total As – ICP-AES

13. 0 2 4 6 8 10 12 J (46.01) L (27.54) H (24.57) K (20.37) G (13.03) I (9.12) D (5.90)C (5.63) B (4.06) E (3.86) F (3.62) A (1.49) M (24.05) N (6.26)Q (5.79)O (5.28) R (5.47) S (3.16)P (1.96) V (1.86) T (1.41) SPLP Arsenic Concentration (mg/L) As(III) As(V) Total As Retention (kg/m 3 ) New Weathered SPLP New & Weathered Wood (Simulated Rain Water)

14. Leachate As Conc. vs CCA Retention 0 1 2 3 4 5 6 7 8 9 10 05 1520253035404550 0 2 4 6 8 10 12 14 02468101214161820222426 kg/m 3 New Weathered Total As Conc. (mg/L) Total As Conc. (mg/L) SPLP Rainwater TCLP DI Water Seawater

15. Environmental pH pH Experiment - New Wood (0.32 pcf) Cr(III) predominates Cr(VI) observed at high pH values

16. Unburned wood Cr as Cr(III) No Cr(VI) observed SPLP New & Weathered Wood (Simulated Rain Water)

17. Ashing results in converstion of Cr(III) to Cr(VI) Cr in ash leachate exists as Cr(VI) Ash – SPLP and TCLP

18. Ash Results for Chromium Low Retention Level Wood Leaches More Cr

19. As & Cr species leaching pH dependent At environmental pH range (6-10) - As ~ 5mg/L - Cr ~ 1 mg/L More As leaching from weathered wood than new wood  As(III) As Leaching in rainwater, TCLP, SPLP comparable. Seawater less. Incineration results in the conversion of some Cr(III) to Cr(VI). Greater conversion for lower retention levels. Summary

20. ? ? Questions ?