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Options for accelerated boron treatment: A practical review of alternatives
1985 - IRG/WP 3329
Boron wood preservatives are almost exclusively applied by momentary immersion and block diffusion storage. Alternative techniques are described which can be used to accelerate boron treatment. Diffusion coefficients have been derived to define the acceleration of diffusion with increasing temperature. Schedules are described for pressure impregnation of green timber, involving steam conditioning, evacuation and alternating pressure method treatment. Timber Preservation Authority penetration and retention requirements can be met in approximately 4-5 h. The optimum schedule, however, included a 12 hour holding period between steaming and preservative treatment. A method of applying boron preservatives as a vapour is described, Trimethyl borate vapour reacts with wood moisture to form boric acid. The kinetics of this reaction, however, are very fast. This limits treatment to timber dried to very low wood moisture contents.
P Vinden, T Fenton, K Nasheri


The use, approval and waste management of industrial wood preservatives. A preliminary report
1994 - IRG/WP 94-50033
The structure on the wood preservation through the world is heterogenous. Environmental legislation, approval policy and application practices differ in each geographical region and in individual countries. This preliminary report gives a rough estimation of the production of treated timber, the use of wood preservatives and a bief summary of environmental status of wood impregnation in selected countries.
A J Nurmi


Alternatives to CCA for ground contact protection of timber: a perspective from UK on performance and service life expectations
2002 - IRG/WP 02-30289
The proposed amendment to the European Union's Marketing and Use Directive (1976/769/EEC) in respect of arsenic in CCA wood preservatives seeks to restrict the use of CCA across the European Union. CCA is an extremely important wood preservative in the UK from the manufacturing of the product to the extent of use of CCA-treated timber. Based on our experience and judgement on the use of CCA and on published literature, there do not appear to be any wholly equivalent alternatives to CCA in terms of cost and effectiveness of performance, particularly under the high hazard conditions of ground contact. This is because, although industry can offer alternative products which are approved for use on the basis of laboratory and indicative field tests, these alternatives are often more costly, behave somewhat differently and do not have the same robust track record of in-service experience. This paper presents a perspective from the UK on arsenic-free alternatives and, using examples of selected results from across the world, estimates the service life performance that the end user might expect. The evidence available indicates that about 2 or 3 times as much CC or CCB is required to give equivalent performance to CCA, 1.5 times as much copper azole and 3 times as much ammoniacal copper quaternary compounds (ACQ). It appears that users cannot expect comparable robustness of performance from the treated wood products and must pay a cost penalty for what is not universally accepted as unequivocal health and environmental gains.
E D Suttie, A F Bravery, T B Dearling


Why did Japan replace CCA by alternatives?
2004 - IRG/WP 04-50215
Since chromated copper arsenate (CCA) was technically introduced into Japan in 1963, CCA was used for extending service life of various wood commodities, especially sill plates (dodai) in Japanese houses. However, the problem on the disposal of CCA-treated wood waste became public and related industry concern, and questionnaire survey conducted by Japan Wood Preservers’ Industry Association indicated that Japanese treatment plants could not meet the new strict criterion (tolerance limit) of arsenic (<0.1 mg/) in the discharged water in the revise regulation, Water Pollution Prevention Act in 1995. In addition, on the basis f the fact that alternatives to CCA were domestically standardized in 1995 (JUS K 1570, 1995), Japanese wood preserving industry came to a self-imposed decision to restrict the use of CCA. Alternatives actually appeared in the marketplace in 1991, and a drastic increase in their use has been prominent since 1996. They account for over 85% of total amount of wood produced by pressure-impregnation with preservatives.
H Ishida, T Ito, M Yamai, H Matsusaka, K Tsunoda


Alternatives to preliminary oven-drying prior to spot-testing treated timber for borate or TBTN preservative penetration
1995 - IRG/WP 95-20067
Commonly-used penetration test procedures for timber treated with borate or organotin wood preservatives demand preliminary oven-drying before application of the spot-testing reagent(s), in order to achieve reliable results. The delay of 12 hours or more during oven drying is often a nuisance. Modifications to the spot-testing procedures, involving alternative solvents and acidification conditions, have allowed the preliminary oven-drying step to be replaced by a very short heating period after application of the reagents, reducing the total testing time to a few minutes. Reliability of the modified procedures has been determined for several timber treatments, over a range of treated timber conditions, and sensitivities of the modified procedures have been determined by chemical analysis of spot-tested material.
M J Kennedy, A Zosars, J Norton


Alternatives to CCA-treated Pinus radiata as vineyard posts
2004 - IRG/WP 04-50212
An estimated 10 million trellis posts per year are used in Australian vineyards and about 75% of these are CCA-treated Pinus radiata. CCA-treated Pinus radiata posts are brittle and at times in short supply. Use of some products containing CCA is being restricted in Australia. Recently, plantation forestry has expanded rapidly for disposal of industrial and irrigation wastewater. Thinnings from these plantations are used as firewood, mulch or simply dumped. Thinnings could be treated and used as vineyard posts. Consequently, our research was conducted to investigate the alternatives to CCA and the suitability of plantation thinnings as vineyard posts. Results have shown a moderate, but not statistically significant, difference in bending strength between CCA and ACQ-treated debarked Pinus radiata posts, in favour of CCA. On average there was no significant difference in bending strength between PEC and ACQ-treated debarked posts of hardwood species (P = 0.54), although two species showed borderline significant differences in favour of ACQ. However, some hardwood species treated with ACQ had more posts rejected due to splitting compared with the same species treated with PEC. No ACQ or CCA-treated Pinus radiata posts were rejected because of splitting.
M Mollah, J Smith, K McCarthy, L J Cookson


Management strategies for the disposal of CCA-treated wood
2000 - IRG/WP 00-50155
A two-fold management strategy is presented for the disposal of wood treated with chromated copper arsenate (CCA). The first part focuses on the use of alternative wood treatment preservatives. The second part of the management strategy addresses short-term disposal issues (less than 25 years) by developing new methods to handle the waste. A set of seven alternative wood preservatives were evaluated through this study. Issues evaluated included efficacy, depletion, corrosion, and costs. Results indicate that viable alternatives are available for CCA-treated wood for the lower retention levels (4 to 6.4 kg/m3). The development of disposal-end management strategies for CCA-treated wood began by tracking the discarded wood within the disposal sector of the State of Florida, USA. It was found that existing disposal methods, which included disposal within unlined landfills and recycling either as mulch or wood fuel, were not acceptable. New disposal-end management strategies evaluated included treatment methods for CCA-treated wood ash and two sorting technologies for separating CCA-treated wood from other wood types within the disposal stream. Results indicate that citric acid is effective at removing arsenic from CCA-treated wood ash. Chemical stain and x-ray based methods were found suitable for sorting treated from untreated wood.
H M Solo-Gabriele, T G Townsend


Durability of some alternatives to preservative treated wood
2004 - IRG/WP 04-30353
The environmental discussion in Sweden has lead to an increasing use of naturally durable domestic wood species and wood treated according to alternative methods for use above ground. A number of these alternatives have been tested according to field- and laboratory tests and compared to wood treated with preservatives for above ground use. Seven untreated wood species, four alternative wood treatments labelled as environmentally friendly and four wood preservatives are included in the study and as references CCA-treated and untreated pine sapwood were used. The best results against wood decaying organisms were obtained with acetylated wood and heat treated wood. Among the tested naturally durable wood species pine heartwood from Gotland (a pine very rich in wood extractives) and oak were the best, but none of these were as good as acetylated wood or preservative treated wood. After 14 months testing against mould and blue stain, preservative treated wood was less attacked than any other tested material. Among the untreated wood species oak and pine heartwood from Gotland were the best and among the alternative treatments heat treated spruce was the best.
M-L Edlund


LCA examination of preservative treated timber products and alternatives; initial results
1995 - IRG/WP 95-50040-04
Co-operative development of an LCA methodology suitable for application to preservative treated products has been carried out, based on scoping assessments of two products, CCA treated fenceposts and creosote treated distribution poles. The general results of these scoping exercices are described, based on the CCA case study. These include the identification of critical stages in the life-cycle on the basis of a range of environmental concerns, assessment of the relative importance of these impacts, identification of critical areas for detailed attention in continuing work. The importance of correctly drawing the life-cycle boundary is clearly demonstrated, in relation to preservative treated timber products which both recycle wastes and byproducts, and may, themselves be recycled. A particular concern for the industry is the importance and availability of risk based impact assessments. The relationship between current and desired LCA impact assessment methods is described, and the data requirements for making progress are discussed.
W Hillier, R J Murphy, D J Dickinson, J N B Bell


Environmental Impacts of CCA-Treated Wood: A Summary from Seven Years of Study Focusing on the U.S. Florida Environment
2003 - IRG/WP 03-50205
Wood treated with chromated copper arsenate (CCA) was identified in 1995 as the cause of elevated arsenic concentrations within wood fuel used for cogeneration within Florida. Since this time a research team from the University of Miami and University of Florida has evaluated the environmental impacts of CCA-treated wood within the State. Research has focused on two distinct areas: in-service leaching of the CCA chemical and disposal pathways for the discarded product. In-service leaching was evaluated by sampling soils located below 9 pre-existing decks (8 CCA treated and 1 not CCA treated) and 2 decks (one CCA treated and one untreated) constructed over a leachate collection system. Results showed that CCA-treated decks leach chemicals in quantities that will impact soil quality. For the pre-existing decks, the average background soil arsenic concentrations were 1.5 mg/kg. Immediately below the pre-existing decks the average soil arsenic concentration was 28.5 mg/kg. Runoff for the decks constructed over a leachate collection system contained over 1 mg/L arsenic and chromium. Arsenic in the runoff was predominately in the +5 valence; however, some As(III) has been measured. A considerable effort by this research team has been placed on evaluating the fate of CCA-treated wood upon disposal. The research has shown that the quantities of discarded CCA-treated wood will increase significantly in the future. Current disposal pathways for CCA-treated wood include construction and demolition (C&D) debris landfills (which are generally unlined in Florida) or inadvertent mixing within mulch and wood fuel that is produced from recycled C&D wood. Samples collected from C&D debris facilities located in Florida indicate that CCA-treated wood can represent up to 30% of the recycled wood by weight. Research has shown that the CCA chemical is capable of leaching from CCA-treated wood (both in the unburned form and as ash) in quantities that exceed regulatory thresholds established by the U.S. Environmental Protection Agency, thereby suggesting that discarded CCA-treated wood should in many cases be managed as a hazardous waste. When CCA-treated wood represents 5% or more of a recycled wood mixture, the ash from its combustion will typically be characterized as a toxicity characteristic (TC) hazardous waste. Both new and weathered CCA-treated wood has been found in a majority of cases to leach arsenic at concentrations greater than the TC regulatory limit. Results from chemical speciation analysis indicate that unburned wood leaches arsenic primarily in the +5 valence and chromium in the +3 valence. Chemical speciation of the ash however was much more variable with some samples showing significant amounts of As(III) and Cr(VI). Commercial mulch purchased at retail establishments in Florida also was shown to leach arsenic at levels that exceeded the State’s risk-based Groundwater Cleanup Target Levels. The presence of leachable arsenic within the mulch was attributed to the presence of CCA-treated wood. Potential solutions to the CCA-disposal problem have been explored including options for waste minimization and disposal-end management of the treated wood. Waste minimization focuses on the use of alternative wood treatment preservatives that do not contain arsenic. Non-arsenical chemicals evaluated include ACQ, CBA, CC, and CDDC. These alternatives were shown to leach less arsenic but more copper than CCA-treated wood. Options for disposal-end management explored through this study include sorting technologies to separate CCA-treated wood from other wood types. Sorting technologies explored included the use of a chemical stain and two systems based upon the use of lasers or x-rays. Chemical stains were found to be effective for sorting small quantities of CCA-treated wood. Both the laser and x-ray systems were shown to be a very promising technologies for sorting large quantities of wood in a more automated fashion.
H M Solo-Gabriele, T G Townsend, J D Schert


Durability of some alternatives to preservative-treated wood. Progress report 2: Results from field tests after 5 years’exposure
2007 - IRG/WP 07-30442
A number of alternatives to preservative-treated wood have been tested according to EN 252 (stake test) and a specially designed ground-proximity field test, the latter in Sweden as well as in Hawaii, USA. Seven untreated wood species and four alternative wood treatments labelled as environmentally friendly (acetylation, linseed oil, heat treatment, vinyl polymer) were included in the study. Four copper-based wood preservatives and CCA were used as references and untreated pine (Pinus sylvestris) sapwood as control. Results after five years’ exposure showed that • Preservative-treated wood, with some exceptions, in general had far better performance than any of the untreated wood species and alternatives tested. • Amongst the alternatives, acetylated wood had a performance comparable to preservative-treated wood. • Heat-treated wood performed well above ground but poorly in ground and should therefore not be used in direct contact with the ground. • Linseed oil-treated wood with a high retention of linseed oil performed well, but because of poor appearance it seems difficult to use successfully in practice. • Larch heartwood performed better than any other untreated wood species tested – slightly better than both oak heartwood and pine (Pinus sylvestris) heartwood. • The ground-proximity test method was considered to be of doubtful value for an easy evaluation of the performance of wood above ground.
M-L Edlund, J Jermer


Sustainable Mycological Alternatives in Natural forest and Conifer plantations in México
2012 - IRG/WP 12-10792
Concepts of mycoforests, mycosylviculture and their relationship to education, production and sustainable management of fungi in forests in México are analyzed. These concepts may be applied in Mexican protected areas, parks and forestry rural communities and improve socio-economic conditions. Two decades ago commerce of wild edible mushroom in the world was relatively small; mushroom industries were selling their products in a rather informal way. At the end of the 80´s important changes in mushroom commerce occurred; and it became organized in activities such as mushroom picking, cleaning, processing and packing and selling to retailers. Mushrooms prices may depend on factors such as: size, freshness, color, abundance, appearance, flavor, texture and familiarity of sellers and buyers with the species. Currently natural forests and forest plantations where mushrooms grow produce an important income in some European countries. Those countries have multifunctional forest practices integrating mushrooms into sustainable forest management. Mexicans living in most rural forestry conditions are used to picking and eating wild edible mushrooms every year. Natural forests in protected areas and national parks are ideal places for implementation of mycosilviculture and mycopark projects, mushroom courses may be offered to park officers and people living in rural communities inside parks and protected areas. These activities will serve to educate people and generate yearly income for them and these activities should be conducted in keeping with current laws to achieve sustainable management and conservation. Forest management programs and mushroom harvesting practices for commercial and home purposes use should be regulated to ensure sustainability. Thus, mushrooms pickers should buy mushroom picking permits, price to accord to their activities. Money obtained from these permits can be reinvested in forest and edible mushroom management that focuses on multifunctional conservation practices. Countries already applying some degree of mycosilviculture practices to mycoparks or truffle culture include France, Italy, Spain, Portugal, United States of America, New Zealand, Australia, Argentina, Chile, Israel and Morocco. Every year these countries produce significant income from wild edible mushrooms.
F Garza Ocañas, A Carrillo Parra


Durability of alternatives to CCA-treated wood - Results from field tests after 11 years exposure
2013 - IRG/WP 13-30633
The present study was initiated as a consequence of restrictions against the use of CCA-type wood preservatives in Sweden in the 1990s. New copper-based formulations were introduced on the market and to some extent, also alternatives to preservative-treated wood, such as thermally and chemically modified and linseed oil treated wood as well as heartwood of non-tropical naturally durable wood species like oak, pine and larch. For most of the alternatives to CCA, no or very limited documentation on durability properties was available at that point. Field trials in and above ground were therefore started at test sites in Sweden and Hawaii, USA. Results after 11 years’ testing in Sweden and 9 years in Hawaii are presented, and the main conclusions are: • All the natural durable species tested were severely attacked by decay after 11 years exposure in Sweden, both in and above ground, and after 9 years above ground exposure in Hawaii • For the “alternative treatments” acetylation performed best, both in and above ground and is the only treatment, preservative treated wood included, that obtained a durability comparable with CCA-A. • Thermally modified wood had initially no visible sign of decay, but lost a good deal of its strength during treatment. After prolonged exposure, however, both in ground and close to ground the fungal degradation increased and after 11 years it is severely attacked. • A low level of linseed-oil treatment gave almost no protection. Linseed oil-treated wood with a high retention of linseed oil performed well, but because of the poor appearance the use in practice seems limited. • Wood treated to Use Class 3 according to EN 335-1 is not recommended for use in ground and consequently, most of them performed well above ground, less good in ground but better than the naturally durable wood. Of the chromium and arsenic free preservatives Impralit KDS was the least successful, much likely due to its comparatively lower copper content. • The different test methods gave the same order of ranking of the three groups of materials tested, although the rate of degradation differed.
P Larsson Brelid, M-L Edlund


Screening method to test efficacy of fumigants against fungi and preliminary data on the efficacy of sulfuryl fluoride
2014 - IRG/WP 14-20551
Methyl bromide is being phased out and there is an urgent need to find a suitable replacement that is effective in reducing exotic pest establishments via trade in wood products. Efficacy data for established phytosanitary fumigants were mostly developed for arthropods and nematodes, and limited information exists for plant pathogens. Increased interest in developing a fast screening process for fungi has prompted this work. Small scale sulfuryl flouride fumigations were conducted in 10 L chambers at six target concentrations (40-240 mgL-1) at 20 C for 24 h against 23 fungal species. Fungi were grown on barley/grain, which was placed in borosilicate glass tubes covered on both ends with a felt cloth to allow uninhibited gas penetration while minimizing the risk of fungal contamination. This allowed simultaneous testing of numerous species/isolates followed by 100% recovery of controls and without contamination of all other isolates exposed to six target sulfuryl fluoride concentrations. Preliminary data have shown that 13 out of 23 species survived the 240mgL-1 exposure. Additional research is needed to test efficacy against more isolates, and under different temperatures and exposure times before experiments closer to field conditions are conducted.
A Uzunovic, A Mukherjee, R Mack, P Elder, S Myers


Bundle tests - Simple alternatives to standard above ground field test methods
2016 - IRG/WP 16-20581
Within this study we applied different new above ground test set ups to untreated Norway spruce (Picea abies Karst.) and Scots pine sapwood (Pinus sylvestris L.) which are frequently used as reference or control species in wood durability field tests. The overall aim of this study was to find a simple alternative method to the few standardized above ground field test methods, such as the L-joint and the lap-joint methods, and to overcome some of their shortcomings (e.g. costly and time-consuming specimen preparation, occurrence of hardly detectable interior rot behind sealants or coatings). Therefore, different bundle type specimens were exposed above ground and monitored in terms of moisture content for one year and fungal decay for up to eight years. Both wood species decayed rather fast and all four different bundle compositions accelerated decay compared to single stake shaped specimens. Brown rot was the dominating rot type independent from the set up and the wood species. The global moisture content (MC) of the specimens was not extremely high, but obviously wetting close to the contact faces was sufficient to allow fungal infestation and decay. Also from a practical point of view the set ups performed in a promising way: specimen preparation was simple and inexpensive, decay assessments were easy, and decay progress sufficiently fast, partly faster than expected from a moderate moisture induced risk as determined for all four bundle type specimens.
C Brischke, L Meyer-Veltrup


Review of Leaching Experiments of CCA-Treated Wood and Wood Treated with Copper-based Alternatives
2017 - IRG/WP 17-50330
The objective of this study was to compare leaching rates of various wood preservatives from treated wood and the tests used to gather this information. The preservatives compared included CCA and the copper-based alternatives, MCQ, ACQ, and MCA. The tests compared included AWPA E11, SPLP, TCLP, and environmental leaching tests. Among all of the tests evaluated, environmental tests most closely simulate natural environments. Compared to environmental tests submersion based tests such as AWPA E11 resulted in artificially high leaching rates. The leaching rates obtained by the synthetic precipitation leaching procedure (SPLP) were the closest to those predicted by the environmental tests. In general, MCQ, ACQ and MCA – treated wood leach more copper than CCA primarily because they have higher retention levels of copper for the same use applications. Despite this, advantage of the copper-based alternatives is that they do not contain or leach arsenic or chromium.
A Jones, J Marini, H Solo-Gabriele