1. Development of a Chemical Stain for Identifying Arsenic-Treated Wood Amy Omae August 18, 2005 Medley, FL

2. Background Identification methods for arsenic-treated wood  Visual method  Augmentation methods XRF, LIBS, AA analysis  Arsenic test kits Arsine gas Wipe  Copper specific stains (PAN indicator) Alternative treated wood (ACQ, CBA, CC, CDDC) EXPENSIVE HAZARDOUS DAYS OR WEEKS INACCURATE IDENTIFIES COPPER NOT ARSENIC

3. Background Similarity of phosphate and arsenate Colorimetric identification methods  Ascorbic acid Unable to prevent phosphate interference  Vanadomolybdophosphoric acid Unable to achieve a noticeable color  Stannous chloride… PhosphateArsenate

4. Stannous Chloride Stain Standard Methods, 1995  Intended for the detection of phosphate, PO 4 3-  Colorimetric reaction  BLUE PO 4 3- +12(NH 4 ) 2 MoO 4 +24H +  (NH 4 ) 3 PO 4 12MoO 3 +21NH 4 + +12H 2 O (NH 4 ) 3 PO 4 12MoO 3 + Sn 2+  (molybdenum blue) + Sn 4+  Interference: Arsenate, AsO 4 3- PhosphateArsenate

5. Stannous Chloride Stain Modifications  Reducing sensitivity to phosphate 1) Ammonium Molybdate 2) Stannous Chloride

6. Stannous Chloride Stain Modifications  Reducing sensitivity to phosphate 1) Ammonium Molybdate 2) Stannous Chloride Combined Reagent

7. Stannous Chloride Stain Reagents Separated Reagents Combined Arsenate Phosphate

8. Dissolution Method 20-mL sample vial  10 mL distilled water  9 drops combined reagent 8 parts ammonium molybdate 1 part stannous chloride  0.5 g sample (shredded wood or sawdust) Reaction time: 30-45 minutes Maximum intensity: ~5 hours

9. Dissolution Method ACZA-treated wood  Ammoniacal Copper Zinc Arsenate  Western U.S.  Maximum intensity: ~2 hours (4.0 kg/m 3 ) Untreated CC CDDC CBA ACQ Borate CCA

10. Dissolution Method None Faint Blue (0.025–0.070) Light Blue (0.071–0.220) Medium Blue (0.221–0.399) Blue (0.400–1.149) Intense Blue (>1.150) Untreated 4.0 kg/m 3 CCA 0m 0s 15m 0s 22m 30s 31m 40s 39m 15s53m 30s1h 8m 0s 2h 30m 0s 5h 30m 0s λ = 690 nm

11. Dissolution Method Field test  Recycled wood Sample Result Determined Chemical Treatment Preservative Reaction Time of Stannous Chloride Stain PAN Indicator (+/–) Elements Detected by XRF Unit (Average, ppm) CrCuAs A–<216.3174.7<10Boratenone B–<205.3<35.7<9.3Boratenone C+<284<34<10.3Untreatednone D+<241.7<51.3<11.7Untreatednone E+<261.310248<9.7Coppernone F+<253.31481<18Coppernone G+<2366013<10ACQnone H+9194.35412.36431.7CCA17 min 24 sec I+2526.31418.71476.3CCA37 min 42 sec

12. Dissolution Method Shelf life (6 months; ends August 26, 2005)  Reagents must be stored separately

13. Other Application Methods Interference with Untreated Wood Whole wood application

14. Other Application Methods Ash  Masking color of ash Wipes  Simulate human hand  Analyze wipe with dissolution method stannous chloride stain  New wood  Effective; similar reaction time  Weathered wood  Effective; reaction time ~4 hours UNTREATED4.0 kg/m 3 CCA40 kg/m 3 CCA

15. Future Objectives Additional field testing on playgrounds MDL for phosphate and arsenate Adjust pH to reduce reaction time Prepare consumer instructions Submit technical report to:

16. Thank you! Questions?