Laboratory investigations about the mobility of some inorganic wood preservatives in soils
E Melcher, R-D Peek
Wood preservatives and components of wood preservatives leached from impregnated wood can enter the soil and thus contribute to the pollution of the groundwater. However, there is lack of understanding concerning the interacting parameters of wood preservative, leachate, soil and soil solution. To characterise of the behaviour of active ingredients and for the assessment of their environmental impact, leaching and diffusion processes are of basic interest with which the concentration of the relevant ions in the soil solution is determined by the reactivity of the ion, and by the type of linkage between the ion and the soil. The concentration and the specific behaviour of the ions in the solid and liquid phases can be investigated using different methods, e. g. using soil column tests (lysimeter). Several designs of lysimeter have been tested with water-soluble wood preservatives and the results been compared with the behaviour of wood preservative components leached from impregnated wood. As a result of the variability of the experimental set-up, of the wood preservatives and of the different soils tested, it became obvious that a standard procedure has to be developed. By means of some examples of varying results the similarities and differences of different procedures are discussed.