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

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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.