Most research in the last few decades has focused on the development of new strategies to control biological attack and the means to quantify this. Comparatively little work has been done to examine the effect that treated timber might have on its surrounding environment. This presentation will describe a methodology that attempts to detect any changes which might occur in the soil microflora following the introduction of timber treated with a number of chemical agents containing organic active ingredients (a.i.). It was also the purpose to isolate organisms that can break down organic a.i.. A technique was developed to determine whether the presence and nature of a timber preservative influenced the size and composition of a microbial population that colonised timber when buried in soil. Samples of treated timber were incubated in a solution eluted from soil that contained a diverse, viable microbial population. After incubation, the size and composition of the microflora both in the eluate and adhering to the timber was examined.
Methods for the determination of biocide emissions from treated materials into water and air were developed and tested in order to support a comparative ecological assessment of biocidal products. Leaching tests, experiments with simulated rain, extraction cleaning of carpets and emission chamber tests were performed with a series of treated materials. The experiments focused on the effect of changes in the procedure as well as characteristics of the specimens and demonstrate the suitability of the proposed methods for biocides of different product types.
It was demonstrated that emissions of biocides into water can be compared on the basis of leaching tests in which the emission kinetics of the active ingredients are recorded. However, the water volume per surface area and the timetable for water changes have to be defined in such tests. Functions of flux rates related to time can be well described for inorganic compounds, whereas modelling of the data is more complicated for organic substances.
Emission chamber tests using 20-litre and 23-litre glass exsiccators, originally developed to study volatile organic compounds, were successfully adapted for the investigation of the emission of biocides from treated materials which are usually semi volatile organic compounds. However, test parameters and the method of analysis have to be adapted to the substances to be determined.
Generally, it was found that the emission curves for the semi volatile organic compounds investigated differ from those of volatile organic compounds.