Norway spruce is one of the most frequent tree species in our region, and it is frequently used for construction applications. When used in higher use classes, it has to be protected against attacks by fungi and insects. Prolongation of wood service life is important for lower maintenance costs and increased reliability of the infrastructure. To protect spruce wood in hazardous environment, copper based wood preservatives are frequently used. To elucidate what is happening with Cu substances in the old telecommunication poles and fence, impregnated with Cu products, samples of various types were prepared for radial distribution of Cu, for determining the fungicidal properties and for determination of Cu fixation in the wood. All investigated material was used in the fourth use class. Using X-ray fluorescence spectroscopy (XRF for Cu analysis) we found out that the content of Cu was lowering from the top to the bottom of the pole. Cu and Cr was traced all over the pole in the upper part of the pole. In the reel cut from the middle part, Cu and Cr were traced only in the first 6 cm; in that taken from the bottom just to 4 cm in the interior. Fungicidal properties revealed the upper part of the pole to be much more resistant than the bottom. An average weight loss of the samples exposed to the fungus 'in vitro' was 14 %, showing that wood was no longer of use. Fixation experiment clearly indicated that there was no sign of leaching, as the Cu was fixed in wood and all of the unreacted Cu already leached from the wood during its service life.
|
