Biocide leaching was investigated for acrylate and vinyl acetate based coatings containing biocides either as liquid formulations or microcapsules. Laboratory and field tests indicate similar relations of results on carbendazim, diuron, terbutryn and OIT from different coatings in laboratory and field experiments. Emissions were higher in EN 16105 laboratory tests than from vertically installed test specimens exposed to weathering, and slower for microencapsulated biocides. Competing processes that cause losses of active substances can occur in both tests, but to a higher degree in field experiments. Emission curves related to runoff water were similar in repeated field experiments. Relative humidity, temperature and global radiation were identified as meteorological factors that affect leaching by complex interaction besides the amount of driving rain.
Leaching of biocides from construction products is currently a research topic receiving attention from the European regulation authorities (CEN/TC 351).
In this paper we have focused on the leaching behaviour of CBA (copper-borateazoles) treated Pinus sylvestris.
To better define the chemistry of the leaching phenomena, two leaching tests (a static equilibrium test and a dynamic surface leaching test) have been carried out on untreated and treated wood, which offered more information about how the leaching of biocides interferes with other substances released from the wood structure.
Eluates, in liquid and lyophilised form, were further analyzed by analytical methods.
Organic (tebuconazole) and inorganic (Cu, B) biocides were quantified and several organic compounds have been identified (e.g.
carboxylic acids, phenols, amines, etc.).
Also, the total amount of phenols and of carboxylic groups was determined.
Results on inorganic compounds are in accordance with previous studies made on treated wood.
Furthermore, organic carbon, tebuconazole and other organic compounds' behaviour was extensively investigated.
This study aims to complete existing leaching data and to help developing a chemical model for several biocides in wood, including Cu, B and tebuconazole.
The wood protection industry has refined their products from chrome-, copper-, and arsenate-based wood preservatives toward solely copper-based preservatives in combination with organic biocides. One of these is Cu-HDO, containing the chelation product of copper and N-cyclohexyldiazenium dioxide (HDO). In this study, the fate of isotope-labeled (13C) and nonlabeled (12C) Cu-HDO incorporated in wood sawdust mixed with soil was investigated. HDO concentration was monitored by high-pressure liquid chromatography. The total carbon and the δ13C content of respired CO2, as well as of the soil-wood-sawdust mixture, were determined with an elemental analyzer-isotopic ratio mass spectrometer. The concentration of HDO decreased significantly after 105 days of incubation, and after 24 days the 13CO2 concentration respired from soil increased steadily to a maximum after 64 days of incubation. Phospholipid fatty acid-stable isotope probing (PFA-SIP) analysis revealed that the dominant PFAs C19:0d8,9, C18:0, C18:1ω7, C18:2ω6,9, C17:1d7,8, C16:0, and C16:1ω7 were highly enriched in their δ13C content. Moreover, RNA-SIP identified members of the phylum Acidobacteria and the genera Phenylobacterium and Comamonas that were assimilating carbon from HDO exclusively. Cu-HDO as part of a wood preservative effectively decreased fungal wood decay and overall microbial respiration from soil. In turn, a defined bacterial community was stimulated that was able to metabolize HDO completely.