1. Comparative Laboratory Leaching Test Methods to Study Post-Treatment Storage Period Impacts on CCA Leachability and Fixation in Treated Kempas ( Koompassia malaccensis ) Heartwood Andrew Wong and Lai Huat Choi Andrew Wong and Lai Huat Choi Faculty of Resource Science & Technology, University Malaysia Sarawak (UNIMAS), Kota Samarahan, Sarawak, Malaysia

2. INTRODUCTION

3. CCA Preservatives  CCA preservatives is one of the most effective wood protecting chemical for many years  Environment issues of CCA components leaching in the media - lead to restrictions of CCA application.  Many countries have even switched to organic-based preservative

4. Laboratory leaching test studies – some concerns  Need to devise suitable harmonise leaching test methods for comparison of biocide risk assessments between labs leaching test  But also need to have a lab leaching test that is realistic to actual environmental exposures of wood preservatives - trying to relate lab results to the “real world” - the extent of rainfall and other climatic effects between regions  EN84 leaching test may be too severe for natural non-aquatic exposures of treated wood  Any prospects for a relatively milder lab leaching test system?

5. Aim of Study  Compare 3 laboratory leaching test methods (denoted as: EN84, EN84-1 and EN84-2, severe to mild leaching).  Leachability of CCA in heartwood of freshly treated Kempas (Koompassia malaccensis).  To determine if CCA leaching from kempas is arrested with longer storage fixation periods.

6. MATERIALS & METHODS

7. Wood Material Preparation Preservative treatment and conditioning 14-days laboratory leaching tests Elemental analysis of leachates Data analysis

8. Wood Material Preparation  Timber species: -Kempas …permeable heartwood (Koompassia malaccensis) (Koompassia malaccensis) Structural-used Malaysian hardwood (roof truss, Structural-used Malaysian hardwood (roof truss, utility poles) utility poles)  Air dried wood block samples (20 x 20 x 20 mm) cut from sawn timber  Test blocks end-grain sealed with Nippon paint and conditioned at 105 0 C, 48 hours, and weighed oven dry (g) before CCA treatment

9. Preservative Treatment & Storage Periods  Replicated Kempas wood blocks impregnated with Type C CCA-salt to target uptake retention of 5.6 kg/m 3  Freshly treated wood stored for periods of 0 day, 2 days, 1 week, 2 weeks & 4 weeks at ambient temperature Initial vacuum (1 kgf/cm 2 ) Pressure (14 kgf/cm 2 ) 30 min 2 hr

10. Laboratory Leaching Tests TestEN84EN84-1EN84-2 Initial Vacuum Impregnation? Yes (30 min) No Initial Dipping in Water? NoYes Leaching Periods 2 weeks Immersion in Water 24 hours Only 5 hr daily Water Change? 2, 24, 48, 72, 96 hr and every 48 hr 24, 48, 72, 96 hr and every 48 hr Daily

11. CCA Component Analysis in Leachates  Cu & Cr determined by FAAS  As determined using AAS EDL Lamp system  Component losses expressed in µg/ml  Cumulative leaching losses ( µg/ml) for each of Cu, Cr & As over the leaching test duration

12. RESULTS

13. Cumulative Cu leaching (µg/ml) by 3 lab. methods EN84 EN84-1 EN84-2

14. Cumulative Cr leaching (µg/ml) by 3 lab. methods EN84EN84-1 EN84-2

15. Cumulative As leaching (µg/ml) by 3 lab. methods EN84EN84-1 EN84-2

16. Cumulative plot for leaching of Cu (ppm) among 3 leaching methods 0 day 2 wk 4 wk 1 wk2 days EN84 EN84-1 EN84-2

17. Cumulative plot for leaching of Cr (ppm) among 3 leaching methods 0 day 2 wk 4 wk 1 wk2 days EN84 EN84-1 EN84-2

18. Cumulative plot for leaching of As (ppm) among 3 leaching methods 0 day 2 wk 4 wk 1 wk2 days EN84 EN84-1 EN84-2

19. Table: Total Leaching ( µ g/ml) of CCA Components for Menggris by EN84, EN84-1 & EN84-2 Methods Fixation periods Leaching methods CuCrAs -----------------(µg/ml)----------------- 4 wk EN84 1.1 abcde 1.1 abcde 1.6 ab 1.6 ab 1.4 bcd 1.4 bcd 4 wk EN84-1 0.7 abc 0.7 abc 1.7 ab 1.7 ab 0.9 ab 0.9 ab 4 wk EN84-2 0.5 a 0.5 a 0.6 a 0.6 a 0.5 a 0.5 a 2 wk EN84 1.5 de 1.5 de 2.1 b 2.1 b 1.8 cd 1.8 cd 2 wk EN84-1 0.9 abcd 0.9 abcd 1.8 ab 1.8 ab 1.1 bc 1.1 bc 2 wk EN84-2 0.7 ab 0.7 ab 0.6 a 0.6 a 0.5 a 0.5 a 1 wk EN84 1.7 e 1.7 e 1.5 ab 1.5 ab 2.0 d 2.0 d 1 wk EN84-1 1.5 de 1.5 de 2.1 b 2.1 b 1.8 cd 1.8 cd 1 wk EN84-2 0.7 abc 0.7 abc 0.7 a 0.7 a 0.5 a 0.5 a 2 days EN84 1.4 bcde 1.4 bcde 1.6 ab 1.6 ab 1.6 cd 1.6 cd 2 days EN84-1 1.8 e 1.8 e 2.0 ab 2.0 ab 2.1 d 2.1 d 2 days EN84-2 1.4 cd 1.4 cd 1.2 ab 1.2 ab 0.9 ab 0.9 ab 0 day EN84 2.6 f 2.6 f 3.7 c 3.7 c 3.1 e 3.1 e 0 day EN84-1 2.4 f 2.4 f 4.7 cd 4.7 cd 2.9 e 2.9 e 0 day EN84-2 4.0 g 4.0 g 5.8 d 5.8 d 4.0 f 4.0 f Within- column values sharing the same letter do not differ significantly (multiple comparisons)

20. CONCLUSIONS

21.  Among the CCA components for the 3 laboratory leaching tests, the order of leaching severity was: Cr > As > Cu.  EN84-2 method gave expectedly milder leaching than EN84 and EN84-1.  No significant difference (P<0.05) in CCA leachability between methods EN84 and EN84-1

22.  Wood blocks (4 wk fixation / EN84-2 method) showed the lowest CCA components leaching.  Obviously, wood blocks (0 day fixation / EN84-2 method) showed the highest CCA components leaching.  Overall increasing storage period improves CCA fixation (reduces leachability) but does not appear to completely fix CCA on to Kempas heartwood

23. ACKNOWLEDGEMENT  Unimas Fundamental Research Grant  Unimas Postgraduate Fellowship for H.C.Lai  Mr Nigel Lim from Sarawak Forestry Corporation  IUFRO SAP partial travel support donated by Korea Forest Research Institute (FRFI)

24. THANK YOU!