Migration of active ingredients from treated timber into fresh water
H Klipp, H Willeitner, K Brandt, A Müller-Grimm
Spruce roundwoods and segments were treated with three different wood preservatives. Two of them containing copper and chromium the other one free of chromium. After fixation (3 weeks, 20°C) the specimens were leached by using artifical rain or by shaking the segments for one hour in contact with demineralized water. The water was analysed for the relevant elements of the preservative tested. Leachability of the components from the copper-chromate treated wood decreases. After 4-8 leaching cycles an almost constant migration of wood-preservatives, depending on the leaching method and the pH-value of water applied, was determined for the chromate containing preservatives. In the course of leaching cycles a constant rate of migrated copper from the preservative free of chromium was determined after 4 - about 17 leaching cycles. After 16 leachings of the segments the leached copper as calculated on the copper retention was determined to 1.6 - 5% for the chromium containing preservatives and about 22% for the tested variation of the new type of preservative.