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In-ground evaluation of a copper azole wood preservative (Tanalithâ E) at a tropical Australian test site
1996 - IRG/WP 96-30100
A field trial to determine the in-ground termite and decay resistance of Pinus radiata D. Don impregnated with a copper azole formulation, TANALITHâ E, has been established at a tropical site in the Northern Territory of Australia. Four retentions of TANALITHâ E, containing 1.54, 2.08, 2.92 and 4.30 kg/m³ of Cu, are being evaluated. For comparison, Pinus radiata specimens treated to two retentions (0.56 and 1.18 kg/m³ of Cu) of the benchmark CCA preservative TANALITHâ C, have also been included in the test. Treated specimens (including controls) have been assessed for degrade by subterranean termites and fungal decay, after 4, 7, 16 and 27 months of exposure, using a scale ranging from 4 (sound) down to 0 (failed). Over the duration of the trial, specimens have been contacted by the economically important species of termites Mastotermes darwiniensis Froggatt, Coptotermes acinaciformis (Froggatt), Schedorhinotermes spp. and Heterotermes spp. After 27 months of exposure, the mean termite and decay scores for replicate test specimens indicate that the performance of TANALITH â E is comparable to CCA.
J W Creffield, J A Drysdale, N Chew

A study of decay type variability in variously treated Fagus sylvatica and Pinus radiata field test stakes exposed at a vineyard for 30 - 45 months
1998 - IRG/WP 98-10271
Pinus radiata test stakes were treated with 10 kg/m3 of CCA plus 4 lower retentions in a geometric series of 1.5. Fagus sylvatica was treated with 15 kg/m3 and 2 lower retentions. Both timber species were also treated with equivalent retentions of various new generation preservatives (P. radiata was also treated with creosote). Whilst these stakes were exposed at 11 sites in New Zealand (NZ) and 2 in Queensland Australia, this paper reports only data from a single NZ site where preservative and timber species effects on decay type were particularly pronounced. Of particular interest was the finding that copper-azole and copper-quat. treated pine was less susceptible to soft rot attack but more susceptible to attack from tunnelling bacteria, compared to CCA treated wood. Beech was not attacked by tunnelling bacteria but was attacked by an unusual type of fungal cavitation/erosion. These, and other preservative and timber species effects on decay type are discussed.
R N Wakeling, A P Singh

Fungus cellar testing as an evaluation method for performance of treated timber in ground contact
2001 - IRG/WP 01-20227
A fungus cellar method for the accelerated evaluation of performance of treated wood in ground contact is described. The test soil comprised of sandy loam, vermiculite and Japanese horticulture soil "Kanumatsuchi" in a ratio of 6:2:2 by volume. The soil was inoculated with the dominant test fungus isolated with selective medium from decayed wood samples. Pairs of treated and untreated wood specimens Japanese cedar in contact with each other were buried vertically for two thirds their length. Assessment of the specimens was carried out periodically using the FFPRI graveyard damage index six- grade scale. Important factors for accelerating decay were the moisture control of the mixed soil, temperature and relative humidity, and the maintenance of fungus activity. The fungus used for inoculation favored a soil water holding capacity (WHC) of 50-80%. Under these conditions the untreated control specimens had a damage index in six months equivalent to three years FFPRI graveyard test service life, the decay accelerating rate by the fungus cellar to the graveyard test was 6 times. Under higher soil moisture conditions (WHC>80%) in the fungus cellar, soft rot was dominant and the decay rate was slower. DDAC treated specimens (8.4kg/m3) had a damage index of 2.6 in three years and 3.0 in four years. DDAC treated specimens (8.2kg/m3) in the graveyard test have been shown to be durable for 12 years (damage index of 2.3 in ten years and 2.6 after 12 years). This fungus cellar method has been shown to accelerate decay in DDAC treated specimens 3 times or more in comparison to the FFPRI graveyard test. On the other hand specimens treated with Copper-azole (6.0kg/m3 as retention of actives) had a damage index of 0 after eight years. The average service life in the FFPRI graveyard test is not decided as the Copper-azole treated specimens are in sound condition so it is not yet possible to evaluate the accelerating rate for the Copper-azole by the fungus cellar method. The fungus cellar method will be an useful method for the accelerated evaluation of performance of treated wood in ground contact provided the test conditions can be controlled.
Y Nagano

Natural exposure weathering tests: Their role in the assessment of wood preservative efficacy
1993 - IRG/WP 93-20006
Previous work has demonstrated the potential and usefulness of natural ageing procedures in e evaluation of wood preservative efficacy. This results from the combination of physico-chemical influences and microbiological interactions with both substrate and wood preservative. In this paper, results are presented for a range of biocide types. Discussions are centred on the value of natural exposure weathering tests for preservative efficacy assessment and the importance of biological persistence in the design of effective wood preservatives.
G R Williams, J Brown

Laboratory termite testing of copper boron tebuconazole
2000 - IRG/WP 00-20192
The American Wood Preservers' Association laboratory choice and no choice termite test (AWPA E1-97) was performed on a formulation of copper azole, which is comprised of copper, boric acid, and tebuconazole. The formulation tested has a ratio of copper:boric acid:tebuconazole of 25:25:1. So as to examine the impact of leaching, the southern yellow pine wafers were treated with and without boric acid at the nominal retentions of 3.3, 4.9 and 6.5 kg/m3. Although considerable field test data are available on this system (Tanalith E and CBA-A), laboratory data of this type was unavailable. Thus, these tests are intended to compliment termite efficacy of the copper azole preservative. The samples were exposed to Reticulitermes flavipes and to Coptotermes formosanus in the Mississippi State University and University of Hawaii laboratories, respectively. Wafers treated with CCA Type C (oxides) at 4.0 and 6.4 kg/m3 retentions were used as controls, as well as untreated pine. The laboratory results show that copper azole and CCA-C performed well at all retentions against both Reticulitermes flavipes and Coptotermes formosanus, whereas the untreated controls had significant weight losses, e.g. 50%.
R F Fox, E A Pasek, J Patel

Laboratory evaluation of the termiticidal effectiveness of TanalithÒ 3485
1995 - IRG/WP 95-10109
The termiticidal effectiveness of the copper azole TANALITH 3485 was evaluated with the benchmark preservative TANALITH C in a laboratory bioassay using two species of subterranean termites, Mastotermes darwiniensis Froggatt and Coptotermes acinaciformis (Froggatt). Retentions of TANALITH 3485 tested were 0.15, 0.24, 0.285 and 0.40% m/m Cu and for TANALITH C 0.025, 0.05, 0.08 and 0.095% m/m Cu. Under the conditions of the bioassay, TANALITH 3485 at the retentions of 0.24, 0.285 and 0.40% m/m Cu and TANALITH C at the retentions of 0.05, 0.08 and 0.095% m/m Cu (0.20, 0.32 and 0.38% m/m total active elements [TAE], respectively) were each successful in protecting Pinus radiata D. Don test specimens against significant attack by Mastotermes darwiniensis. The lowest retention of each formulation failed. When exposed to Coptotermes acinaciformis, all retentions of TANALITH 3485 tested were successful in protecting test specimens whereas TANALITH C at the lowest retention of 0.025% m/m Cu (0.10% m/m TAE) failed. Specimens treated with TANALITH 3485 exhibited little, if any, toxicity to Mastotermes darwiniensis. The formulation appeared to have imparted a repellent and/or antifeedant effect on Mastotermes darwiniensis. In contrast, TANALITH C displayed toxicity to Mastotermes darwiniensis thereby causing a decrease in survival of termites throughout the bioassay as the retention of preservative in test specimens increased.
J W Creffield, J A Drysdale, N Chew, N-K Nguyen

Leaching of preservative components from pine decking treated with CCA and copper azole, and interactions of leachates with soils
2001 - IRG/WP 01-50171
Radiata pine decking was treated with CCA and copper azole preservatives to Australian H3 retention using conventional and modified Bethel schedules, and air-dried. Treated decking boards and durable hardwood controls were subjected to leaching in weather-exposed decks, and matching 19mm cubes were leached in extended AWPA E11-97 lab tests. Deck runoff and E11 leachate water was analysed after rain events and E11 change points. After 10 months, decks had lost up to 700mg Cu, 175mg Cr, 600mg As, 750mg B, 10 mg tebuconazole or 18000 mg tannin per square meter of deck, but flux rates had not yet reached zero for any component. Leaching from E11-97 blocks was much faster and greater than from the decks. Extending the leach period from 14 days to 50 days increased the amount of leaching by up to 40%. Even after 50 days, flux rates were measurable for most components. Deck leachates were applied to three soils using the draft OECD soil leaching column procedure. After elution, the soil was segmented and analysed. Although boron was more mobile than others, components tended to be retained in the topmost (first contacted) layer.
M J Kennedy, P A Collins

Efficacy of copper:propiconazole and copper:citrate systems in ground contact exposure at a site with copper tolerant fungi
2003 - IRG/WP 03-30305
Southern yellow pine (SYP) sapwood field stakes were treated with copper alone (ammoniacal copper carbonate, ACC) at four levels, or three levels of copper (1.6, 3.2, or 6.4 kgm-3, as CuO), air-dried, then re-treated with propiconazole in a light organic solvent at 0.07, 0.3, or 0.7 kgm-3 retentions. In a separate study, SYP field stakes were treated with three levels of ACC to give 6.7, 13.4 or 29 kgm-3 retentions, or the same ACC levels plus citric acid at 38% of the CuO level. These ground-contact stakes were installed at a test plot which has copper tolerant fungi, and inspected regularly for fungal and termite degradation. At the most recent inspection, the copper azole stakes had been exposed for 118 months and the copper citrate stakes for 100 months. For the copper azole stakes, copper alone was only effective at the highest copper retention (10 kgm-3, CuO basis). In contrast, the copper azole-treated stakes were adequately protected with 1.6 kgm-3 CuO and the highest (0.7 kgm-3) level of propiconazole, or 3.2 kgm-3 CuO and 0.3 or 0.7 kgm-3 propiconazole, or 6.4 kgm-3 CuO and 0.07 kgm-3 (or greater) propiconazole. For the copper citrate stakes, stakes treated with copper alone performed slightly better at all three retentions than the copper:citrate-treated stakes. We conclude that the co-addition of propiconazole provides increased protection against copper tolerant fungi and other wood-destroying organisms, with increased azole levels necessary as the copper retention is lowered. In contrast, the co-addition of citric acid did not increase the efficacy of copper.
D D Nicholas, T Schultz

Diffusion modeling of inorganic wood preservative leaching in service
2005 - IRG/WP 05-50224-5
To evaluate the potential environmental and health implications of leaching of inorganic wood preservatives in service under different conditions, there is a need for a predictive model that provides estimates of the rate and extent of leaching over a wide range of product dimensions and exposure conditions. In this paper, we show that the leaching behavior of inorganic preservative components from wood in continuous water contact can be characterized by three easily measured parameters: total leachable component (Le) based on intensive leaching of fine ground material; amount of dissolved or dissociated component (Di) in water saturated wood; preservative component diffusion coefficients (Dt,l) in the transverse and longitudinal directions. Use of the applicable D and Di or Le in a diffusion model allows the prediction of total amount leached and emission rate at different times of exposure. Both D and Di increase somewhat with increasing ambient temperature. Laboratory determined parameters for alkaline copper quaternary (ACQ), copper azole (CA), chromated copper arsenate (CCA) and borate (DOT) wood preservatives are used to predict leaching rates from larger lumber samples. Preliminary comparisons of predicted leaching with measured leaching of larger samples in laboratory and natural rain exposure indicate that the approach is surprisingly effective at predicting leaching performance but some model refinements are needed for some components such as copper in CCA to account for the slow dissolving of a component of the preservative available for leaching.
L Waldron, P A Cooper, Y T Ung

Occupational exposure risk assessment at a commercial treatment plant using copper azole preservative
1998 - IRG/WP 98-50101-15
Experience with traditional water-based preservatives such as chromated copper arsenate (CCA) applied in closed system vacuum pressure impregnation plants has shown that operator atmospheric exposure is low during normal operation. TANALITH E is a commercially available copper azole wood preservative introduced as a chrome and arsenic-free alternative to CCA based on the actives copper, tebuconazole and boric acid. To assess operator exposure, extensive atmospheric monitoring was conducted around a TANALITH E treatment plant facility, including static monitoring points during routine plant operations and long-term operator exposure. The atmospheric concentrations of the three actives and two of the amine carriers were subsequently determined by analysis. The results from the evaluation are discussed with particular emphasis on the assessment of risk to treatment plant operators working with copper azole wood preservatives.
A S Hughes, M Connell

Impact of leachates from CCA- and copper azole-treated pine decking on soil-dwelling invertebrates
2002 - IRG/WP 02-50183
This study assessed the short-term effects on non-target soil invertebrates of leachates from a naturally durable hardwood and timber treated with two copper-based wood preservatives. Natural rainwater leachates from kwila decking, and radiata pine-decking treated with CCA or copper-azole, were collected and applied on mown lawn soil in Brisbane, Queensland. The soil study consisted of 5 treatments: an independent control (replicates untreated), wet control (replicates treated with rainwater only), CCA, copper azole and kwila-extractive leachates. Two applications of each treatment were made. Soil samples were collected before application and then twice after the first application (3 and12 days) and 3 times after the second (3, 8 and 12 days). Soil arthropods were extracted from soil cores using Tullgren funnels. Frequency analysis and multivariate techniques were used to analyse the data for treatment effects. Soil invertebrates were dominated by mites (84%), which were identified to family level. We did not detect any difference in the density of mites except in the kwila-extractive leachate, where mite density increased significantly. However, there were detectable differences in mite community structure between all treatments, indicating differential effects of the treatments on the soil arthropod community.
N Crumière, A House, M J Kennedy

Comparative performance of copper azole and copper-chrome-arsenate treated rubber wood in Australian, Malaysian and New Zealand tests sites
2000 - IRG/WP 00-30213
Rubberwood (Hevea brasiliensis) has been used for non-structural products where appearance is important. It has rarely been used for structural uses where preservative treatment is required. In order to evaluate the in-ground durability of preservative-treated rubberwood, test stakes (20 x 20 x 500 mm3) were treated to four retentions of CCA and copper azole (Tanalith® E) and installed in test sites in Australia, Malaysia and New Zealand . After 2- 4 years exposure, copper azole is out-performing CCA at equivalent retentions where a fungal hazard dominates. At the Malaysian test site, CCA proved the more effective preservative in a severe termite hazard. Neither preservative is likely to adequately protect rubberwood in critical in-ground situations.
J A Drysdale, M E Hedley, E Loh, L T Hong

A comparison of analytical and visual techniques used for assessment of weathering properties of chromium and copper azole treated timber
1994 - IRG/WP 94-20023
The weathering properties of preservative treated timber were studied by measuring surface lignin loss and by microscopic examination after weathering, and results were related to qualitative assessments of visual appearance after weathering. Measurement of relative rates of delignification of untreated and preservative treated timber obtained by FTIR analysis, and weight loss determined on thin veneers, correlates well with visual assessments of comparative rates of weathering on solid timber exposed to natural weathering in service. Copper Azole treated timber and timber treated with chromium based preservatives showed good resistance to weathering.
J A Cornfield, M D C Hale, G Fettis

Is Field Test Data from 20 x 20mm Stakes Reliable? Effects of Decay Hazard, Decay Type and Preservative Depletion Hazard
2006 - IRG/WP 06-20327
Effects of decay hazard, decay type and preservative depletion hazard on the performance of variously preservative treated 20 x 20 x 500 mm Radiata pine and Fagus sylvatica test stakes across 13 field test sites in New Zealand and Queensland Australia were determined. Radiata pine treated with an ammoniacal copper quaternary preservative (ACQ) (1.56% m/m a.i.) and copper chrome arsenate (CCA) (0.72% m/m a.i.) was susceptible to sudden failure at some of the sites that had a high brown rot hazard whereas pine treated with copper-azole (CuAz) (0.59% m/m a.i.) was not affected, suggesting that CuAz was particularly effective against brown rots. At the most severe brown rot sites ACQ treated pine was more susceptible than CCA and its performance in service may be compromised as a result, as previously occurred for pine treated with acid copper chromate (ACC). Based on overall performance across all sites pine treated with chlorothalonil plus chlorpyriphos (1.07% m/m a.i.) (11% mean soundness reduction (MSR)), creosote/oil treated pine (37% m/m a.i.) (14% MSR) and CuAz (15%MSR) all gave significantly better protection (5% P) than pine treated with CCA (19% MSR) and ACQ (19% MSR). The decay hazards encountered, as determined by mean soundness reduction after 6.5 years, were more severe than encountered in previous studies at some of the same sites and this was linked to differences of intra-site decay type between test plots and associated decay hazard differences. Greater decay rates encountered in this study were, in part attributed to high preservative depletion. At very wet sites, particularly those likely to have a high soil organic acid content, 20 x 20 x 500 mm stakes are probably too small for accurate interpretation of long-term durability of preservative treated wood. Knowledge of the distribution of different decay types across sites tested, coupled with associated decay hazards and preservative depletion hazard, suggested that 4 test sites of clearly defined features would enable comprehensive field testing of preservative treated wood. Selection of sites is not straightforward and requires a rudimentary knowledge of soil type, geology, vegetation and climate, or comprehensive knowledge of the decay types present. In view of the cost of maintaining test facilities, adequate multi-site testing of new wood preservatives may be achievable through cooperation between research establishments. Possibly, current test site selection criteria fall short of ensuring adequate test site parameters are incorporated and maximum cost effectiveness of testing may not always be achieved through duplication of test site parameters between sites of similar but unrecognised properties. Scope for artificial creation of intra-site decay hazard differences is discussed.
R Wakeling

Effects of sodium hypochlorite on compression strength and copper retention of spruce wood treated with copper azole and alkaline copper quat
2007 - IRG/WP 07-40362
This work investigates the effects of sodium hypochlorite on compression strength values and copper retention ratios of refractory spruce wood (Picea oriental L.) treated with the waterborne preservative Copper Azole, (CBA-A, Tanalith-E 3492) and alkaline copper quat (ACQ-2200). Before the copper azole and alkaline copper quat treatment, the samples were immersed in 500 ml of sodium hypochlorite solution for three different durations (2, 4, and 6 hours). A 2 % active ingredient solutions of CBA-A and ACQ were applied for use in vacuum treatment of the sapwood samples. Average copper contents of the specimens were higher than that of the control groups except of the 6-hours sodium hypochlorite treatment in ACQ impregnation. The highest copper value was seen in the variation the 6-hours sodium hypochlorite treatment in the CBA-A impregnation. Compression strength values generally slightly reduced compared to the control groups especially in ACQ impregnation.
S Yildiz, E Dizman, A Temiz, Ü C Yildiz

The effect of additives on copper losses from alkaline copper treated wood
2007 - IRG/WP 07-50246
The replacement of chromated copper arsenate (CCA) by alkaline copper compounds has heightened awareness of the potential impact of copper losses on aquatic organisms. While there remains a healthy debate concerning the actual risk of copper leaching from wood preservatives into aquatic ecosystems, it is clear that reducing these losses will be necessary to avoid continued regulatory actions against the use of preservatives in these environments. While post-treatment processing and coatings can reduce losses, neither is completely effective. Another alternative is to add compounds to the alkaline system to complex or otherwise reduce copper losses, much in the same way that chromium acts in CCA. One possible additive is Di(hydrogenated tallowalkyl) dimethyl ammonium chloride, also know as 2HT, which is a common fabric softener. Preliminary tests suggested that this compound reduced copper losses from alkline copper quat and, in doing so, improved overall biological performance. In this report, we describe additional trials to assess the effect of 2HT on copper migration from wood treated with either ACQ or copper azole (CA). 2HT had a variable effect on copper migration, but was associated with reduced copper losses in some treatment combinations. Further trials are underway to assess the biological efficacy of wood treated with combinations of 2HT and either ACQ or CA.
J Mitsuhashi, J J Morrell, L Jin, A F Preston

Field Trial of Copper Treated Moso Bamboo in Southern China
2008 - IRG/WP 08-30455
The field trial of moso bamboo treated by 9 copper preservatives for 5 years in Guangzhou was conducted in the paper. The result shown that: two ammonia based copper azole formulations F17/F18 and 1 amine copper formulation with boron F10, as well as 2 ammonia based ACQ, at the copper retention of 3.2 kg/m3 or above, have good resistant for decay and fine resistant for termites after 5 year field test at local condition. The result of durability of ACQ-B treated moso bamboo is similar to that of masson pine and slash pine at the copper same retention.
Mingliang Jiang

Above and Below-Ground Copper-Azole and Copper, Chrome Arsenate Depletion from Pinus radiata and Fagus sylvatica at Thirteen New Zealand & Australian Sites
2008 - IRG/WP 08-30460
The objective was to determine the significance of site on preservative depletion from Pinus radiata D. Don and Fagus sylvatica L. 20 x 20 x 500 mm field test stakes treated with a ground contact retention of copper amine plus tebuconazole (CuAz) and copper chrome arsenate (CCA) after approximately 5 years exposure to widely different soil and climate conditions. Site, wood species and their interactions had a dramatic and statistically significant effect on CCA and CuAz-treated pine and beach. Mean Cu depletion for radiata pine treated with 0.72% m/m a.i. CCA after 5.5 years, across 13 sites was less than 1% for above ground portions of stakes compared to 30% for below ground. However, below ground depletions at acidic sites located at a peat bog and a Nothofagus (southern hemisphere beech) forest were 43 and 73% respectively. Mean below ground chromium and arsenic depletions were 9 and 21% respectively but were 22 and 41% at the most severe depletion site (Nothofagus forest). Across all sites, mean above ground depletion of Cu and tebuconazole from radiata pine treated with 0.59% m/m a.i. CuAz, was 19 and 42% compared to 47 and 55% for below ground. Substantially greater loss of copper from CuAz treated wood compared to CCA treated wood, especially for above ground exposure, across all sites, may be significant for wood in service situations where aquatic toxicity of copper is an issue. Beech was more susceptible than pine to loss of copper for both CCA and CuAz. This may have been attributable to less efficient fixation reactions and preservative distribution (macro- and micro-) in beech. The finding that waterlogged sites, and/or sites with low pH caused greatest loss to all treatments irrespective of wood species, in the light of low loss at horticultural sites suggested that the influence of extremes of water availability and of low pH was more important than other mechanisms such as cationic exchange reactions with soil. Particularly high loss occurred at sites where soil was likely to have contained a high organic acid concentration.
R Wakeling

Formation and Structure of Metal Azole Complexes
2008 - IRG/WP 08-30469
Divalent copper and zinc complexes with metal:azole ratio 1:2 were readily formed at room temperature with the fungicides tebuconazole and propiconazole. The structure of copper and zinc tebuconazole acetate and zinc cis-propiconazole chloride were examined by X-ray crystallography. In copper tebuconazole acetate, the copper atom lies on a crystallographic inversion centre and is coordinated to two triazole and two acetate ligands in a trans arrangement. The two binding tebuconazole N atoms and two close binding acetate O atoms form a square plane. The two remaining acetate O atoms have more distant interactions, thus forming an elongated octahedron around the copper atom. The coordination geometry of zinc tebuconazole acetate is tetrahedral and the metal is bound to two triazole and two acetate ligands. The geometry is distorted from regular owing to the size of the tebuconazole ligands. The butyl chains are less folded than for the copper tebuconazole complex, resulting in a more extended molecule. The coordination geometry of zinc cis-propiconazole chloride is also tetrahedral with the metal atom bonded to two triazole and two chloride ligands.
P D Evans, K J Schmalzl, C M Forsyth, G D Fallon, S Schmid, B Bendixen, S Heimdal

Effects of planning and sanding on penetration and retention properties of some softwood species treated with copper azole
2008 - IRG/WP 08-40410
This work investigates the effect of some woodworking treatments on penetration and retention properties of four different (scotch pine—SP, Siberian scotch pine—SSP, Siberian larch—SL, and oriental spruce—OS) heartwood species with the waterborne preservative copper azole (CBA-A). A 2.4% active ingredient solution of CBA-A was applied for use in vacuum/pressure treatment of the heartwood samples. Two different woodworking treatment were used, namely planning and sanding. Maximum and minimum penetration values were measured as percentage of cross-sectional area. Penetration of preservative was also determined by X-ray fluorescence spectroscopy analysis (ASOMA). SP resulted in the highest penetration and retention values complied requirements stated in the American Wood Preservers’ Association (AWPA) standards. Siberian scotch also showed satisfactory results for standard requirements. SL and OS showed lower penetration and retention results than those of pine samples which can be related to their refractory characteristics. On the other hand, woodworking treatments such as planning and sanding done before impregnation process did not affect total preservative and copper retention, moreover, interestingly increased preservative retention of the wood specimens in most variations.
Ü C Yildiz, S Yildiz

Biological efficacy of micronized copper systems
2008 - IRG/WP 08-30485
Soil block, fungal cellar and field stake test data will be presented for micronized copper systems. The copper portion of the formulations is present as a fine dispersion of "micro" particulates while the co-biocide is present as either a soluble quat or an azole containing emulsion. This testing generally used the amine based counterpart as the control preservative system and the micronized formulations perform as well or better than the amine formulations. In 5 year field stake tests in Gainesville, FL, the micronized copper quaternary formulation significantly outperformed the amine copper quaternary formulations. Strength and fixation testing is also discussed.
C R McIntyre, M H Freeman

A Comparison of the Performance of Related Copper Based Preservatives against Soft Rot
2010 - IRG/WP 10-30540
The performance of pine and beech wood treated with either a soluble copper + quat (ACQ type D) preservative system or a particulate copper + quat system was evaluated in unsterile soil using the European standard ENV 807 soft rot decay test procedure. In addition, to compare soft rot performance of soluble and particulate copper directly without the influence of co-biocides, beech and pine test blocks were treated with either a soluble copper formulation or particulate copper system to equivalent copper retentions and then exposed to mixed cultures of soft rot fungi in a vermiculite medium according to ENV 807 Annex A. Relative performance of the different formulations was determined using weight loss data.
M Ray, D Dickinson, K Archer

Performance of Wood Protection Systems at Multiple Field Test Sites Using the Ground Proximity Test Method
2012 - IRG/WP 12-20499
A series of preservative systems were used to treat southern pine ground proximity test samples which were then exposed at a range of test sites located throughout the world. The sites were chosen on the basis of having vastly different Scheffer Climate decay indices. After almost 14 years exposure, distinct differences are apparent in how different preservative systems perform at the different sites, as well as how their relative performance is impacted at different retentions.
A Zahora, A Preston, L Jin

Mold Control for Treated Lumber in Block-Stack Storage Conditions
2012 - IRG/WP 12-30588
The mold development and control for freshly treated and block-stacked wood have been evaluated using a green house mold testing method. The results for the mold resistance of several commonly used water boron preservative treatment systems, such as ACQ, Copper Azole, and borates with and without inclusion of mold inhibitors are presented. The data suggest that the different preservative treatment systems have their own very different mold resistance characteristics. The addition of mold inhibitor or in some cases combination of mold inhibitors or additives can provide effective control of mold development. The results also suggest that the green house mold test method reported here can simulate the worst case scenario confronted by treated wood in block-stack situations during storage, retailing and installation.
L Jin, P Walcheski, A Preston

Removal of nano- and micronized-copper from treated wood by chelating agents
2013 - IRG/WP 13-50294
Micronized and nano-copper (Cu)-based and arsenic and chromium-free systems have received much attention for wood protection in recent years. Because they have different fixation, and micro-distribution properties, such copper systems may be more or less subject to release using known remediation methods than soluble forms of Cu. This study evaluated Cu recovery from wood treated with micronized- or nano-Cu via chemical extraction, and determined optimum release rates of Cu from micronized- and nano-Cu-treated wood compared with the release rates from soluble Cu-based wood preservatives. Chemical remediation in the study included chelating agents EDTA, oxalic acid, bioxalate, and D-gluconic acid at different durations, pH, and concentration levels to remove Cu from treated wood along with distilled water as controls. Cu removal rates increased from around 60% to over 95% when bioxalate was employed in the extraction process for all extraction durations. In extractions of nano CuO-treated wood for 24h, oxalic acid was able to remove 95% of Cu; however, bioxalate was able to remove somewhat less Cu. Bioxalate was, on the other hand, more effective than oxalic acid in removing Cu from ACQ-D, MCQ, MCA, CA-C and Cu-Et-treated wood. D-gluconic acid extractions resulted in the lowest Cu removal rate for nano-CuO. As the pH of D-gluconic acid was reduced from 10 to 2, the percentage Cu removal considerably was improved except for nano CuO. Results suggested that there is no distinctive difference in Cu removal rates among ACQ-D/MCQ, CA-C/MCA and Cu-Et wood preservatives. Nano-CuO was found to be resistant against EDTA extractions. Since it is a weak, noncorrosive, nonvolatile, nontoxic, biodegradable and inexpensive organic acid, D-gluconic acid can be used as an alternative to commercial EDTA and bioxalate in chemical remediation of Cu-treated waste wood.
S N Kartal, E Terzi, B Woodward, C A Clausen, S T Lebow

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