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Organic solvent preservatives. Essays on the ecotoxicology of new formulations
1991 - IRG/WP 3642
The knowledge on the ecotoxicological profile of wood preservatives become more and more important. The acute toxicity against aquatic organisms was examined for oil-borne preservatives, based on combinations of new fungicides (Tebuconazole, Propiconazole, Dichlofluanid) and insecticides (Permethrin, Cyfluthrin). These tests were conducted with fish, daphnia and algae. In principle the different formulations showed similar effects. The results of active ingredients and solvents confirmed the high sensitiveness of daphnia as test organisms. Criteria for hazards for the environment are presented and discussed.
H-W Wegen


Airborne algae as a wood degradation factor
1992 - IRG/WP 92-1549
The occurrence of airborne (aerophytic) algae on wood is a very frequent phenomenon. However, there is currently a lack of information concerning their effect on the wood tissue. Some important genus of algae infesting wood under natural conditions are listed, as well as the results of experimental studies in the "in vitro" culture concerning the effect of two selected algal species on some physico-mechanical properties and on the structure of beech and Scots pine woods.
K J Krajewski, J Wazny


Practicability of bioassays in the evaluation of environmental risks in wood protection
1996 - IRG/WP 96-50071
As an example for the proofing of the practicability of bioassays in the evaluation of environmental risks in wood protection the ecotoxicological behaviour of CCF-impregnated timber was examined. After vacuum pressure impregnation specimen from shaped pine poles were tested on ecotoxicological effects of leachable compounds using sensitive aquatic organisms like fish, Daphnia and algae as bioindicators. According to proper impregnation the influence of leachable compounds from treated timber was significantly lower when compared with the acute aquatic toxicity of the preservative and its ingredients. This indicates the existance of safety factors and allows a differentiated estimation of environmental risks for impregnated wood. A general proposal for an ecotoxicological screening procedure in wood protection is presented.
H-W Wegen


Wood preservation using furanones derived from marine algae
2004 - IRG/WP 04-10506
Halogenated furanones that are analogues of natural compounds extracted from the red seaweed Delisea pulchra were examined in the laboratory for activity against termites and decay fungi. The furanones were found to have broad spectrum activity, some with solution strengths of 0.01% controlling Coptotermes acinaciformis in a filter paper trial, while 2% solutions impregnated into Pinus radiata blocks also gave control. Some furanones prevented growth on filter papers by Perenniporia tephropora (white rot) and Coniophora olivacea (brown rot) at 1% solution concentration. In treated P. radiata specimens, one of the furanones prevented decay by P. tephropora and Trametes lilacino-gilva while there was some decay by C. olivacea. When blocks were artificially weathered and leached, fungi were not controlled. Furanones have potential as termiticides for the protection of house framing, while further research is required for protection against decay fungi in exposed leaching environments.
L J Cookson, R de Nys, P Steinberg, N Chew


Description of a trial with wood preservatives against marine wood boring organisms
1975 - IRG/WP 412
Wood situated in sea water along the Atlantic coasts of the Nordic countries is attacked by marine wood boring organisms. Timber constructions in these waters therefore must be preservative treated. In order to evaluate the effect of various preservatives against marine wood borers, the Nordic Wood Preservation Council (NWPC) organized a rather extensive trial in 1972. In the absence of and while awaiting international standard methods for testing preservatives it was felt that there was a need for a Nordic standard method. The 1972 trial was consequently planned and performed in close cooperation with the standardisation work. The complete standard method was published by NWPC in 1973 (NWPC Standard No. 1.4.2.2/73).
E Norman, B Henningsson


An initial evaluation of the environmental impact of potential marine biocides
1978 - IRG/WP 441
Pilings and other structures in the marine environment are protected primarily by impregnation with creosote alone, or in combination with coal tar or waterborne preservatives such as copper-chrome-arsenate. Some of these materials are considered as possible ecological hazards and face an uncertain future; perhaps newly developed treatments to replace these conventional ones will pose different problems. Today, for a toxic substance to be approved by cognizant government regulatory agencies it must undergo an extensive evaluation to determine its impact upon the environment. Consequently an initial assessment of the potential environmental impact must be determined for all compounds which have shown promise against marine borers and fungi in our investigations. This has been accomplished by determining their toxicity to marine algae which are the primary producers in the food chain. The principal organism used for this purpose has been Phaeodactylum tricornutum Bohlin, but Cyclotella nana and Chaetoceros galvestonensis have also been used.
J D Bultman, P J Hannan


Fouling organisms as indicators of the environmental impact of marine preservative-treated wood
1995 - IRG/WP 95-50063
This study evaluates the use of fouling organisms (epibiota) to assess the environmental impact of preservative treated wood. This paper presents initial findings from treated panels exposed for 6 months at Sagres, Algarve, Portugal. Panels were treated with CCA, two copper-containing quaternary ammonium (ACQ) formulations and creosote, with nominal retentions from 10 to 40 kg/m³ (creosote 25 pcf). The presence of an abundant, diverse and healthy epibiotic community growing on treated wood was used as an indication that the preservative treatment had a relatively low impact on its immediate environment. Algae and mussels (Mytilus galloprovincialis) were the dominant members of the fouling community which developed on all preservative treated wood panels. The biomass (dry weight of organisms) and species diversity of epibiota scraped from the surface of preservative treated wood panels showed the following order CCA > Creosote > ACQ 1:1 > ACQ 2:1. No difference was detected concerning the shell dimension of mussels between treatments, but mussel biomass was much lower on ACQ-treated test samples, indicating that mussel settlement was affected by ACQ treatment, but growth was not. Algal biomass was highest on creosotetreated panels, with biomass on other panels fitting the following sequence: Creosote > CCA > ACQ 1:1 > ACQ 2:1. Copper, chromium and arsenic contents of algae were determined by atomic absorption spectroscopy (AAS). Elevated levels of Cu, Cr and As were found in the macroalgal mat from CCA-treated panels. These levels showed significant positive linear regressions with panel preservative retention levels. Higher levels of copper were found in macroalgal mats from ACQ-treated wood, but showed no linear relationship to panel preservative loadings. Copper levels did not exceed 9 ppm in algal tissue, chromium and arsenic levels were below 1 ppm.
R M Albuquerque, S M Cragg


Algal growth resistance of paints for coating of wood; a laboratory study
1997 - IRG/WP 97-10213
Twelve paints were tested for resistance against algae. In addition, one algicidal compound commercially used for remedial treatments of algal growth on paints was tested for its effectiveness for prevention of algal growth. An agar diffusion bioassay was employed in which paint films on filter paper discs were placed on mineral salt medium and sprayed with an algal suspension containing a mixture of one blue-green alga, Oscillatoria tenuis, and two green algae, Ankistrodesmus gracilis and Pleurococcus sp. Most growth was recorded in plates with discs painted with acrylic paints. Two acrylic paints containing a commercial fungicide at normal or double concentration permitted the same amount of growth as the same acrylic paint without fungicide addition. The solvent-borne alkyd paints and the alkyd emulsion paints were more inhibitory against growth of algae. Only some of the acrylic paints permitted any growth of the green alga Ankistrodesmus gracilis. Acrylic paints containing a commercial algicide inhibited the growth of the Pleurococcus sp. and Ankistrodesmus gracilis but permitted some growth of Oscillatoria on the agar medium used.
J Bjurman


Environmental impact of PCP and NaPCP in the aquatic and atmospheric compartment
1995 - IRG/WP 95-50040-06
PCP and NaPCP were studied for their aquatic toxicity on bacteria, microalgae and daphnids and for their behaviour in the atmospheric compartment with a climatic chamber. Results of aquatic toxicity bioassays showed that toxicity was higher at low pH. This can be explained by the pKa value of 4.7 of PCP and the higher concentration of the non dissociated form of the pesticide at more acidic pH. Volatilization of pentachlorophenol was studied with wood samples treated with PCP in organic solvent or aqueous solution of NaPCP. Test procedures were investigated in a first step. It appears that a period of three weeks minimum after impregnation must be respected before sampling the wood specimens and that the ratio m²/m³ has to be in good agreement with the saturated vapor pressure concentration. These recommandations would imply improvement of some conditions of the French norm NF X 41-566. The release of pentachlorophenol from wood samples treated with PCP was much higher than with wood treated with NaPCP. The different behaviours of PCP and NaPCP suggest that these substances should be considered distinctly.
P Marchal, P Vasseur, G Ozanne


Protective effectiveness of antifouling coatings for wooden boats in the Northern Adriatic Sea
2013 - IRG/WP 13-40634
There are various conventional biocide containing antifouling coatings and some more environmentally friendly paints for boats on the market. However, the question of their performance in accordance with the manufacturers’ statements or guaranties arises. The aim of our preliminary investigation was to state which type of antifouling coating exhibits better effectiveness against fouling organisms in the Northern Adriatic Sea. In order to elucidate this question, the impregnated and coated specimens of Scots pine wood were exposed to the sea water in the Port of Koper, Slovenia. The specimens were treated with different types of antifouling coatings. The most effective ones were those of the soft and hard types. On the other hand, the tested nano-based antifouling finish did not exhibit any protective efficiency against fouling.
M Petrič, M Humar, J Adamek, B Kričej


Colonization of treated and untreated decking materials by bacteria, fungi and algae quantified by qPCR
2015 - IRG/WP 15-20568
The use of durable wood species for wood decking in outdoor applications, e.g. garden terrace (use class 3) is gaining more and more interest on the part of consumers and architects. To get detailed information on the practical use of deckings, a project was started in 2010. In total 71 different decking materials (0.03 m²) were installed and evaluated over 30 months. Beside other parameters, the emphasis was to evaluate the applicability of qPCR (quantitative Polymerase Chain Reaction) technique for measuring the dynamics of increase in biomass of the organism groups responsible for biofilm formation. For this purpose 8 decking materials (durable, not durable, modified and waterbased varnish treated wood species) were investigated concerning surface growth of biofilm forming microorganisms (bacteria, fungi and algae). The surface treatment of the decking material (larch and acetylated pine) with wood preservatives improved the performance concerning the biofilm building, and made them even more resistant to growth of microorganisms than the deckings from species with high natural durability. Periodical maintenance of the decking comprising cleaning, sanding and in some cases also rebrushing of the panels showed an influence on the estimation of biomass directly due to the removal of the biofilm.
E Stoyanova, B Schmöllerl, A Steitz, N Pfabigan, R Gründlinger


Exterior paint for the future - Will there be any dry-film preservatives left?
2017 - IRG/WP 17-50332
Wooden houses have a long tradition in several of the Nordic countries. Wood can be protected in various ways; constructional, chemically and by surface treatment. The use of various types of exterior paints as a surface treatment is a common way to prolong the durability of the wood. To further protect the painted surface against growth of fungi and algae, dry-film biocides remains an essential part of a high quality exterior paint. In Europe, the use of biocides is regulated by the Biocidal Products Regulation (BPR). Dry-film preservatives are just beginning to be evaluated, and already several of the well-known dry-film biocides face challenges with being approved under BPR. This paper will discuss the purpose of applying exterior paint(s), biological growth on painted facades, and the uncertain future of the dry-film biocides in Europe.
H Jensen, M Sandve, S M Lystvet