The fixation and leaching characteristics of 8 Malaysian tropical hardwood (MTH) species treated with chromated copper arsenate (CCA-C) wood preservative were examined. The species evaluated were Acacia (Acacia mangium), Bintangor (Calophyllum sp.), Geronggang (Cratoxylon arborescens), Medang (Litsea sp.), Meranti rambai daun (Shorea acuminata), Putat (Planchonia sp.), Ramin (Gonystylus sp.) and Simpoh (Dillenia sp.). The softwood radiata pine (Pinus radiata) was included for comparison. CCA fixation in wood samples is monitored by reduction of hexavalent chromium to trivalent chromium in expressate for different periods of fixation time. The amount of copper, chromium and arsenic remained as the unfixed state in the treated wood was also determined. Furthermore, leaching test was performed according to the American Wood Protection Association (AWPA) standard E11-06 leaching procedure. Most of MTHs except for Acacia showed relatively low fixation rates, although reduction of hexavalent chromium to trivalent chromium in the species was much faster than those in radiata pine. After a 14-day fixation, high amounts of CCA components were remained as unfixed state in the species, resulting in a significantly high amount of metals in leachate. Based on the results, we suggest that tropical hardwoods such as Geronggang and Ramin are not an environmentally sound species for CCA treatment. Further study will be conducted to investigate the possible cause for the incomplete fixation of CCA components in the treated MTHs.

Download document (325 kb)
free for the members of IRG. Available if purchased.

Purchase this document