Confirmation of Safety and Long-term Durability of CCC (Chitosan-Copper Complex) as An Environmental Friendly Wood Preservatives

本研究的目的是通过化学安全性试验和现场暴露试验来确定壳聚糖-铜络合物（CCC）处理木材的安全性和长期耐久性。在食品和农业化学品安全与评估中心有限公司的私人检查部门对CCC的安全性进行了以下五个项目的调查，即食用毒性试验（LD 50），眼刺激试验，皮肤刺激试验、皮肤过敏试验和遗传毒性试验。CCC眼刺激试验呈强阳性反应。LD_（50）试验CCC远大于2000 ppm。结果表明，CCC是一种安全、环保的木材防腐剂，并通过现场试验对CCC处理木材的耐久性进行了评价。在白蚁群附近埋置7年的木钉未发生破坏，在室外暴露4年的木台也未发生生物降解，从抗白蚁和木材真菌侵袭的机理来看，处理材中CCC的微分布可能起着重要作用。CCC中的铜元素选择性地沉积在射线组织与轴向管胞之间、树脂道内和射线细胞之间形成的“细胞间隙网络”的自由空间中。铜元素的这种选择性沉积对褐腐真菌和白蚁的攻击非常有效。这些研究结果在2002年在印度尼西亚举行的第五届国际太平洋地区木材解剖学会议（PRWAC）和第四届国际木材科学研讨会（IWSS）上发表。

The purpose of this study is to confirm safety and long-term durability of a Chitosan-Copper Complex (CCC) treated woods based on the chemical safety tests and the field exposure testsThe safety of CCC was investigated at a private inspection sector of Safety and Evaluation of Foods and Agricultural Chemicals Center Ltd. for following five items, that is, poison test for eating (LD50), ocular irritation test, skin irritation test, skin allergy test and genetic-poison test. CCC showed strong positive reaction on ocular irritation test. CCC of LD50 test is much larger than 2000ppm. It was confirmed that CCC was very safety and able to recognized as an environmental friendly wood preservatives.Durability of the CCC treated woods, such as CCC impregnated wood-pegs and a CCC treated Sugi-log bench, was evaluated by the field tests. Wood pegs buried for 7 years near the termite colony showed no damages, and the log bench exposed for four years in outdoor also showed no signs of biodegradation.So far as the mechanism of anti-biodeterioration against termite and wood fungi attacks, the CCC microdistribution within the treated woods seemed to play an important role. The copper-elements of the CCC was selectively deposited within the free space of "intercellular spaces networks" which were formed between ray tissue and axial tracheids, within resin canal and between ray cells. This selective deposition of copper elements works very effectively against brown rot fugal attack and termite attack.These obtained results were presented at the fifth International Pacific Regional Wood Anatomist Conference (PRWAC) and the fourth International Wood Science Seminar (IWSS), both were held at Indonesia in 2002.