Year 4 Research Fate of CCA-Treated Wood

1. Year 4ResearchFate of CCA-Treated Wood

2. Objectives • Evaluate Fate of Wood Treated With Preservative Chemicals • Evaluate CCA- and alternative-chemical- treated wood through TCLP and SPLP (Phase I) • Evaluate arsenic species in leachates collected from landfills(Phase II) Note: Complimentary Study on Chromium Speciation

3. Phase I: Leaching of Alternative-Chemical Treated-Wood Products • Samples Include • ACQ-Treated Wood • CBA “ “ • CC “ “ *** • CDDC “ “ • CCA “ “ Treated Through Facility A • CCA “ “ Treated Through Facility B • Untreated Wood • Unknown Treated Wood (?)

4. Sample Processing • 8, 2”x4”x16 ft were purchased

5. Analytical Methods for Alternative Chemicals • Description of Leaching Test Plan • Review of existing methods for analysis of alternative chemicals(AWPA, EPA, and others) • Proposed methods of analysis • Questions for TAG

6. Plan for Leaching • Primary Leaching Tests • TCLP • SPLP • Additional Leaching Tests • Deionized/Distilled Water • Synthetic Seawater

7. Leaching Tests Wood Sample Leaching Test Leachate Analysis Size reduced following standard leaching protocols 18 hour contact, 20:1 Liquid to Solid ratio, Rotary extraction Leachate analyzedusing standardizedmethods

8. Methods of Analysis • Sources of methods: • AWPA Standards • EPA Methods • Instrument Manufacturer Methods • Other • Methods are often matrix specific • The matrix of interest in the this study is aqueous leaching fluid

9. Chemicals to be Analyzed InorganicChemical(s) OrganicChemical(s) Preservative As, Cr, Cu -- CCA ACQ Cu DDAC Tebuconazole Cu, B CBA Dimethyldithio-carbamate CDDC Cu CC Cu Citrate

10. Inorganic Methods EPAMethod AWPAStandard AnalyticalMethod ICP-AES 6010B A21-93 FLAA 7210 A11-93 7211 A11-93 GFAA Note: Methods may require extraction or digestiondepending on the matrix or method

11. Organic Chemical Analysis OrganicChemical AnalyticalTechnique AWPA Method(liquids) DDAC HPLC,Titration A16-A/17-97 CDDC A25-94 * Colorimetric Tebuconazole HPLC, GC A23-94/A24-94 A2-98 Citrate UV Spec

12. Other Analytical Methods • Citrate by Ion Chromatography • Dionex methods manual • Alternative Titration for DDAC • Manufacturer suggestion

13. Proposed Methods • Methods selected based on resources available, time constraints, and analytical objectives

14. Analysis of Inorganic Chemicals • Copper and Boron will be analyzed using ICP, FLAA, or GFAA following US EPA methods (including acid digestion).

15. ICP

16. Perkin-Elmer 5100 FLAA/GFAA

17. Analysis of Tebuconazole • A GC/MS will be used for analysis. • Based on a modified version of AWPA method A24-94 • Detection limit is approximately 100 mg/L

18. Trace 2000 GC/MS

19. Analysis of DDAC (ACQ) • A two-phase titration analysis will be performed following method A17-97.

20. Titration Setup

21. Analysis of CDDC • Analysis will be performed using a colorimetric method specified in A25-94 and instrument methods manual.

22. Hach DR/4000U Spectrophotometer

23. Analysis of Citrate • Analysis will be performed using Ion Chromatography

24. Dionex DX-500 Ion Chromatograph

25. Chromatogram

26. Other Possibilities • Toxicity Tests • MET-plate • Microtox • Algal assay • Yeast assay

27. Questions for TAG • Are we missing any analytes of concern? • Suggestions on methods? • Comments on leaching tests?

28. Arsenic:Toxicity, Mobility & Analytical Methods for Speciation Bernine Khan University of Miami

29. Outline Part I - Characteristics • Arsenic Species • Arsenic Toxicity • Arsenic Mobility Part II - Arsenic Speciation Study • Purpose of Study • Goals for Year 4 • Hydride Generation Method - SDDC

30. Speciation Definition Various species of an element which make up the total concentration of that element - different oxidation states (e.g. arsenic +3, +5, -3) inorganic - contains sulfur organic - contains carbon/hydrogen groups

31. Speciation Why are we interested in speciation? • Not all species are toxic • Total concentration - over-/under-estimate toxicity Standards • EPA’s MCL for DW- 50 mg/L (5 mg/L) As • TCLP limit - 5000 mg/L

32. Arsenic Species Decreasing Toxicity AsH3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide AsB - arsenobetaine (marine) * AsC - arsenocholine (marine) *

33. Arsenic Species Decreasing Toxicity AsH3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate - CCA MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide AsB - arsenobetaine (marine) * AsC - arsenocholine(marine) *

34. Arsenic Species Decreasing Toxicity AsH3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide AsB - arsenobetaine (marine)* AsC - arsenocholine (marine)*

35. Arsenic Species Decreasing Toxicity AsH3 - arsine (gas) As(III) - inorganic arsenite As(V) - inorganic arsenate MMAA - monomethylarsonic acid DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide AsB - arsenobetaine (marine)* AsC - arsenocholine (marine)*

36. Toxicity Data LD50 (mg/kg) 4.5 14-18 1,800 1,200 10,600 10,000 6,000 Arsenic Compound Inorganic arsenite [As(III)] Inorganic arsenate [As(V)] MMAA - monomethylarsonic DMAA - dimethylarsinic acid TMAO - trimethylarsine oxide AsB - arsenobetaine (marine) AsC - arsenocholine (marine) Animal rat rat mouse mouse mouse mouse mouse LD50 - concentration at which 50% of a population dies. Low LD50 - more toxic High LD50 - less toxic

37. Arsenic Mobility Reducing O2 & Eh 0.75 0.50 0.25 0 -0.25 -0.50 -0.75 As(V) +5 Eh-pH diagrammeasure of system state (aerobic/ anaerobic) Most surface waters As(III) - Oxidized As(V) - Reduced Methylation As(III) +3 Most ground waters Eh (volts) AsS +3 As(III) +3 AsH3 (aq) As 0 2 4 6 8 10 12 14 pH

38. Part IIArsenic Speciation Study • Hyphenated techniques • Separation + detection methods • Separate As(III) and As(V) from interfering ions • Detection methods - detect & quantify

39. Purpose of Study • CCA treated wood disposed of in unlined C&D landfills • Leaching studies show significant amounts of CCA leaching from wood under varying pH solutions • Determine the total arsenic & individual concentration of As(III) & As(V) species • Chemical Hydride Generation method

40. Leaching Study(Warner et al. 1990) Arsenic leaching increases linearly with decreasing pH Arsenic after 40 days - retention of 1.99 kg/m3 in new wood Buffer pH % As H2SO4 2.5 40 H2SO4 3.5 23 H2SO4 4.5 17 Buffer pH % As citric acid/NaOH 2.5 - citric acid/NaOH 3.5 68 citric acid/NaOH 4.5 52 citric acid/NaOH 5.5 32 distilled water 7.0 17 borax/HCl 8.5 9

41. Goals for Year 4 • Current Study: • Analysis of As(III) & As(V) by Chemical Hydride Generation (CHG) method • SDDC - CHG method chosen - NaBH4 to reduce arsenic to its gaseous form (arsine) so as to be detected • SDDC method - Test reproducibility using standard solutions

42. Silver Diethyldithiocarbamate (SDDC) Method Current Study 20 10 5 2 1 0 ug

43. Results of SDDC Methods Arsenite [As(III)] Conc. (mg) 20 10 5 2 1 0 Conc. (mg) 20 10 5 2 1 0 Absorbance 0.185 0.082 0.038 0.03 0.018 0.009 Absorbance 0.17 0.072 0.05 0.02 0.018 0.009

44. As(III) Calibration Curve

45. Results of SDDC Methods Arsenate [(As(V)] Conc. (mg) 20 10 5 2 1 0 Conc. (mg) 20 10 5 2 1 0 Absorbance 0.24 0.15 0.078 0.04 0.02 0.009 Absorbance 0.24 0.142 0.08 0.037 0.03 0.015

46. As(V) Calibration Curve

47. Goals for Year 4 • Next Steps: • Determine how best to preserve sample • Analyse GW samples near C&D landfills • Analyse leachate from MSW and C&D(?) landfills

48. Speciation of Chromium

49. Chromium Speciation • Background • Methods of Analysis • Proposed Methodology

50. Chromium Exists as Several Chemical Species Most common oxidation states: 0, +3, +6 0: Elemental Chromium (Cr) +3: Trivalent Chromium Species: Cr+3, Cr2O3 +6: Hexavalent Chromium Species: CrO42-, Cr2O7-