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Eingeladener Vortrag
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The biodeterioration of water-based manufactured formulations, such as polymer dispersions, is a major problem for the producing companies and the users of such products. Industrial preservatives, also known as biocides, are therefore used to protect these and similar products from the effects of microorganisms, predominantly bacteria and yeasts. In the absence of internationally recognised standard methods for determining the resistance of polymer dispersions to microbial growth and the efficacy of biocides used in them, protocols for testing other products, e.g., paints, have been adapted, and other methods produced by manufacturing companies, test laboratories, and academic institutions have been used. Often these do not take into account the specific nature of the materials being tested, the types of organism commonly causing contamination, and the conditions that the polymer dispersions will be exposed to during manufacture, storage, and use. By conducting a series of round-robin, collaborative tests, the member organisations of the International Biodeterioration Research Group Polymer Dispersion Working Group have identified the bacteria that commonly infect polymer dispersions, defined the main parameters necessary for a standard method of test, and developed a protocol that is robust, repeatable, and reproducible. The recommended test involves three repeat inoculations of the material with a previously determined mix of seven Gram-negative bacteria and evaluation of living cells by a simple plating technique. The work reported here, carried out by nine participating laboratories, is a final statistical validation and suggests that the method is eminently suitable as a standard test method.
Guidance on the European Biocidal Products Regulation concerning Efficacy of Wood Preservatives
(2017)
In Europe wood preservatives belong to Product Type 8 (PT8) of the Biocidal Products Regulation (BPR, EU n. 528/2012), which regulates the authorisation of biocidal active substances and products in the European market.
The applicant, who aims to obtain authorization to place a product onto the European market, needs to submit data to substantiate the label claims for the intended uses. Label claims are a central issue in the assessment of efficacy.
The aim of this paper is to raise awareness of the recently issued “Guidance on the Biocidal Products Regulation” concerning the evaluation of efficacy of wood preservatives. This guidance document is addressed to the applicants as well as to the competent authorities of the member states of Europe in charge of assessing efficacy data, and has been in the public domain, in its latest version, since February 2017.
The CEN/Technical Committee 38 “Durability of wood and wood based products” / WG 22 "Performance, assessment and specification” decided to bring the Guidance to a wider audience with the aim of disseminating the information and to trigger discussion among the experts of IRGWP.
An excerpt of the Guidance that is relevant to wood preservative products is presented in an Annex to this paper.
Keywords: Biocidal Products Regulation, BPR, authorisation, Guidance, PT8, curative wood preservatives, preventive wood preservatives.
Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher
mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives.
Drei grundlegend verschiedene Ansätze für Umweltsimulation werden an Beispielen illustriert:
(i) Ganzheitlicher Ansatz - Nachstellen von Umweltmilieus im Labor
Ziel ist hier das Nachstellen von (kombinierten) Umweltbedingungen im Labor; die Umweltparameter werden mit all ihren Wechselwirkungen aufgebracht.
Hauptnutzen ist eine gegenüber der natürlichen Beanspruchung erhöhte Reproduzierbarkeit der Umweltbedingungen. Hat man sein Laborsetup entwickelt, ist es auf verschiedene Materialien anwendbar.
Unter solchen Laborbedingungen ermittelte Lebensdauern sind dabei nicht auf die typischerweise sehr variablen Real-Umweltbedingungen übertragbar.
(ii) Parametrisierter Ansatz - Ermittlung einzelner Materialempfindlichkeiten
Hierbei werden im Labor die Wirkungen separater Umweltparameter auf Materialien nachgestellt. Für eine solche Separation der Einflussfaktoren ist insbesondere die Aufschlüsselung möglicher Wechselwirkungen der Umwelt-parameter (z.B. Mikroklima an bestrahlten Oberflächen) erforderlich. Einzelne (meist Alterungs-) Empfindlichkeiten können qualitativ nachgewiesen werden oder sogar – als Beanspruchungs-Wirkungs-Funktionen – quantifiziert werden, was einen wesentlichen Schritt in Richtung der Digitalisierung der Material¬prüfung darstellt. Insbesondere ist dann auch eine Lebensdauer-vorhersage für vorgegebene Zeitreihen der Beanspruchungs¬parameter umsetzbar.
(iii) Rückwirkungen auf die Umwelt
Umweltbeanspruchungen können zur Freisetzung von Schadstoffen in die Umwelt führen. Durch die Nachstellung kritischer, aber realitätsnaher Einsatzszenarien kann die Menge an freigesetzten Substanzen abgeschätzt werden.
Egal, welcher Ansatz verfolgt wird – ein Vergleich mit der oder einer Real-beanspruchung ist unerlässlich, ebenso wie die Messdatenaufzeichnung (data logging) aller potenziell relevanten Beanspruchungsparameter während dieser Realbeanspruchung.
Obwohl die naturnahe Umwelt – sowohl in der BAM als auch bei der GUS – gegenüber der technischen Umwelt eher untergeordnet auftritt, werden zur Illustration Beispiele aus der naturnahen Umwelt verwendet.
Our earlier study based on historical and scientific analysis showed that Iranians used a considerable range of materials in the sizing process. Unlike many nations who used limited sizing materials to improve the mechanical strength and to smoothen the paper surface, Iranians have used various materials for sizing process from Taimurid (15th century) to Safawid (16th century) and Qajar (19th century) periods. Further to our earlier study on the Sizing Materials used in Persian manuscripts and miniature paintings, scientific analysis was carried out to investigate their behaviour against the mould fungus Aspergillus flavus. In the first stage fourteen different sizing materials that was identified from Persian historical recipes were reconstructed. In the second stage fungicidal property of each sizing samples against Aspergillus flavus fungus were identified that will be presented in this paper.
In this study, we investigated the diverse range of materials used for sizing in Iranian paper manuscripts during the Timurid (fifteenth century) to Safavid (sixteenth century) and Qajar (nineteenth century) periods. Our approach combined historical analysis with scientific examination of reconstructed sizings. We reconstructed 15 sizing materials based on identified Persian historical recipes and analysed their physical, optical, and spectral characteristics. Additionally, we assessed their behaviour against the mould fungus Aspergillus flavus. The results revealed distinctive properties for each sizing material, shedding light on their potential applications in paper preservation. Furthermore, our investigation demonstrated variations in hygroscopicity, thickness, grammage, and ash content post-sizing. The sizing materials also exhibited different effects on paper reflectance properties. Additionally, our study revealed insights into the impact of sizing on burnished papers, indicating that the mechanical process of burnishing did not significantly alter the chemical composition or spectral properties of the paper, with only minor changes in brightness observed in specific cases. All tested sizing materials supported varying levels of mould growth, indicating potential implications for paper conservation. Our findings provide valuable insights into the historical practices of Iranian paper sizing and offer practical considerations for the preservation of paper manuscripts.
Materials are subject to environmental constraints that include biological, chemical and physical factors. To gain confidence about durability and long-term performance of any material, environmental resistance testing procedures have to be amended with modern simulation procedures that include biological components. In fact, any environmentally exposed surface at temperatures lower than 121 °C will be home to microbial growth, even at high salt concentrations, extreme pH, environmental pollution, low water potential, and intense irradiation – everywhere where water is liquid and available. As a consequence, complex microbial ecosystems called biofilms are self-sufficient and found on almost all solid-air-water interfaces. Obviously, environmental changes perturb biofilm development but over a number of seasons, these changes result in relatively stable microbial communities peculiar and adapted to a particular niche and material. Certain microbial settlers are indicative of, and in a real sense mark, a particular biofilm and can, thus, be considered as “reference organisms”. Characteristic reference organisms’ peculiar to specific material-inhabiting communities can be isolated, identified, characterised and used in standard test procedures as well as research into materials science (materials improvement). In this presentation classical microbiological, genetic and molecular methods for studying reference organisms and their roles in materials deterioration will be presented. We will present a set of different reference organisms that are currently in focus of our research and testing development.
Verschiedene Labor- und Freilandstudien zeigen, dass Antrodia vaillantii ein Braunfäuleerreger ist, der chemisch geschütztes Holz (gemäss den Anforderungen der Gefährdungsklasse 4) stark abbauen kann. Hierbei spielt die erhöhte Oxalsäureproduktion des Pilzes und die daraus resultierende Kupferoxalatausfällung im Holz die entscheidende Rolle. Das Kupfer wird auf diese Weise für den Pilz weitgehend unschädlich gemacht und andere Holzschutzmittelbestandteile wie z.B. Chrom- und Arsenverbindungen verlieren ihre Fixierung im Holz und werden wasserlöslich. Dies führt zu Frühausfällen von chemisch geschütztem Holz im Erdkontakt innerhalb weniger Jahre. Laboruntersuchungen haben gezeigt, dass der Holzabbau durch A. vaillantii bei hoher Wasserverfügbarkeit außerhalb des Holzes angeregt werden kann. Das hohe Feuchtigkeitsbedürfnis des Pilzes ist möglicherweise die Ursache für den Befall von Holz in bis zu 1,2 m Bodentiefe. Neben der hohen Bodenfeuchte gibt es Anhaltspunkte für weitere Parameter, die zur positiven Selektion von A. vaillantii und damit seiner stellenweise starken Ausbreitung führen. Diese sind hohe Toleranz gegenüber bereits vorhandenen niedrigen pH-Werten im Boden, das aktive Einstellen niedriger pH-Werte im Boden durch Säureabgabe und die Festlegung von Kuper als Kupferoxalat.
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.
The paper descibes a novel method to detoxify pine wood (Pinus silvestris L.) treated with CCB-, CCF- CC-, and Cu-HDO-type salt preservatives. In the process of biological detoxification organic acids produced by strains of Antrodia vaillantii and other brown rot fungi are used for the dissolution of the previously fixed inorganic compounds. These findings are the basis for applying an acid pulping process (FORMACELL) developed by Nimz and Schone (1992) at the BFH, Hamburg, to detoxify salt impregnated wood waste with a mixture of acetic and formic acid. First results achieved with wood chips from treated poles after approximately 20 years of service life show that the obtained pulp contains less than 100 ppm of Cr and Cu. The pulp properties were neither influenced by the Cr and Cu ions nor by the age of the poles. The extracted quantities of Cr and Cu remain with the lignin whereas the acids are evaporated and recycled in the pulping process.
The fungus cellar test is a common means to get reliable data on the long term performance of treated wood in soil contact. A constantly high humidity and a suitable of water holding capacity for a range of micro-organisms provide high decay rates in untreated wood and produce intensive microbial pressures on wood treated with biocides. Presently a range of biocides are under test in the BAM fungus cellar and the results will be presented for the following types of biocides: Tebuconazole in combination with copper and boron (5 years fungus cellar), quats with copper and boron (5 years fungus cellar) and Cu-organic compound combined with copper and boron (3 years fungus cellar). Figures will be shown on the development of the Modulus of Elasticity (MOE) over the years and on an assessment of the stakes according to EN 252.