Your search resulted in 528 documents. Displaying 25 entries per page.
Working plan: Second international collaborative field trial
1995 - IRG/WP 95-20056
This paper describes the scope, objectives, and approaches to be used in the second international collaborative field trial approved by the Scientific Programme Committee for partial funding in 1994. The trial is designed to develop a broad data base on causal mechanisms, interactions, and factor affecting the performance of treated wood in ground contact. The trial encompasses 12 different field test sites representing all continents except Antarctica. Preservatives were chosen to represent new technologies and include oilborne, waterborne copper-organic, and water-dispersible systems. CCA is used as the reference system. Task forces to research the following areas are described: accelerated soilbed testing, decay types/modes of failure, preservative depletion, abiotic factors, and copper tolerance.
H M Barnes, T L Amburgey
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
Micro-Distribution of Micronized Copper in Southern Pine
2008 - IRG/WP 08-30479
For copper-based preservatives to be used in ground contact, penetration of copper into the cell wall is believed to be important to protect the wood from soft rot fungi. Preservatives containing soluble copper are known to do this. It is not known whether preservatives containing particulate copper will also migrate into the cell wall in sufficient quantities to control soft rot decay. An AWPA standard E11 leaching test found that leachate from southern pine blocks treated with a preservative containing particulate copper (Micronized copper quat) contained copper ions, suggesting that copper-containing particles in the treated wood slowly release mobile copper. Southern pine sapwood samples treated with wood preservatives containing soluble (ACQ-D) and particulate copper (Micronized copper quat), as well as untreated southern pine sapwood, were analyzed by Environmental Scanning Electron Microscopy (ESEM) and Energy Dispersive X-Ray Spectrometry (EDS). Copper was detected in the lumens of wood treated with both preservatives, and not in the untreated control. Moreover, the presence of small amounts of copper in the cell walls of samples treated with Micronized copper quat and ACQ-D was indicated by ESEM and EDS. This was further supported by the results of a fungal cellar test and a field stake test which demonstrated that wood treated with Micronized copper quat is resistant to soft rot attack. Future work will investigate copper mobility from particles lodged in the lumens.
R Stirling, J Drummond, Jun Zhang, R J Ziobro
Alkaline copper treated wood for use in residential decking
2008 - IRG/WP 08-30490
Alkaline copper quaternary ammonium compound (ACQ) treated decking was exposed in a field experiment and the mobile copper assessed based on that collected in the leachate. The amount of copper which leached was modeled after 4 years. The results showed that boards which leached most chemical initially provided the greatest loss over four years. The reduction in the mobility of copper with time was calculated and found to approach zero after about 11 years. The application of water repellant slowed down the loss of copper and could extend the mobile copper duration beyond that in control samples. The migration of copper onto check surfaces was confirmed with retentions exceeding that reported to protect wood above ground from spore germination by basidiomycete fungi.
J N R Ruddick
Corrosion of fastener and connector in contact with alkaline copper treated wood – it is a problem
2008 - IRG/WP 08-40437
For many decades, chromated copper arsenate (CCA) was the most common wood preservative used in North America for residential and industrial applications. Since December 31, 2003, the use of CCA for residential application was voluntarily terminated. One of the most widely accepted alternative wood preservatives in Western Canada is Alkaline Copper Quaternary Compound (ACQ). This paper will compare the corrosion data of CCA-treated wood with that of ACQ treated wood at a similar preservative retention. It also discusses the appropriate methodology for carrying out the corrosion studies. A modified draft American Wood Protection Association (AWPA) corrosion test method was used, where fasteners were sandwiched between two pieces of treated wood and exposed to the continuous water mist at an elevated temperature. All fasteners were tested for resistance of the coating to mechanical damage, prior to exposure. The study demonstrated that ACQ treated wood is indeed more corrosive than CCA treated wood. The study also showed that the application of water repellant to ACQ treated wood significantly reduced the corrosion rate. The best estimation of the corrosion rate was the measurement of the loss in the average core diameter in combination with a visual evaluation of the fastener and corrosion products.
J N R Ruddick
Comparison of laboratory and natural exposure leaching of copper from wood treated with three wood preservatives
2008 - IRG/WP 08-50258
Standard and non-standard laboratory and field leaching tests were used to compare copper leaching from wood treated to above ground and ground contact specified retentions for three wood preservative systems, CCA-C, ACQ-D and a micronized copper formulation with quat DDAC as co-biocide. Copper leaching was highest for the ACQ formulation. Percent leaching was lowest for the micronized copper system (MCQ) but amount of copper leached (mg/m2) was higher for MCQ than for CCA because of the higher copper content in the former formulation. The amounts of copper leaching varied considerably from test to test, but in most cases, the relative amounts of copper leaching from wood treated with the three formulations were consistent. One exception was the AWPA E20 soil leaching test which provided variable results, that showed that leaching of copper from CCA and MCQ samples was more similar to that from ACQ samples than observed for the other test methods. Also, the natural exposure tests (horizontal and vertical exposure) has less dramatic differences among the preservative systems.
P A Cooper, Y T Ung
Copper to quat ratio in alkaline copper quat (ACQ) wood preservative - Effects on fixation and leaching of preservative components in red pine
2009 - IRG/WP 09-30496
This study investigates the effect of the relative proportion of copper oxide (CuO) to didecy dimethyl ammonium carbonate (DDACb) in an alkaline copper quat (ACQ) formulation on the rate of copper fixation or stabilization and the resistance of treated wood to leaching of copper and quat (DDACb). Red pine samples were treated with ACQ, having CuO to DDACb ratios of 2:1 (the normal ratio for ACQ-D), 1:1 and 1:2, at concentrations of 0.6%, 1% and 1.5%. Treated samples were wrapped in plastic and post treated at 500C. Samples were squeezed to express solution, which was analyzed for copper to measure the percentage copper fixed at different times during post treatment conditioning. Conditioned samples were subjected to AWPA E11 laboratory leaching experiments and the amounts of copper and DDACb leached from the samples were analyzed. A decrease in relative proportion of copper in the ACQ formulation from a CuO to DDACb ratio of 2:1 to 1:1 and 1:2 resulted in a substantial reduction in the time required for the fixation of copper. There was a significant decrease in the amount of copper leached from the species studied with reduction of relative proportion of copper in the ACQ formulation. The reduction in leaching was higher for samples treated with concentrations of 1% and 1.5% ACQ compared to the sample treated with 0.6% ACQ. Formulation having 1:1 CuO to DDAC ratio appears to be the most promising, considering the positive effects of reduced copper ratio on copper leaching and fixation time and the minimal effect on DDAC leaching.
S Pankras, P A Cooper, T Ung, L Awoyemi
Re-Distribution of Copper in the Cell Walls of Wood Treated with Micronized Copper Quat
2009 - IRG/WP 09-30506
Wood treated with copper-based preservatives to be used in ground contact may fail to inhibit soft rot fungi if penetration of copper into the cell wall is insufficient. Preservatives containing soluble copper are known to penetrate the cell wall; however, it is not known whether preservatives containing particulate copper will also migrate into the cell wall in sufficient quantities to control soft rot decay. A method was developed to accelerate and detect re-distribution of copper into the cell wall. Copper was found to re-distribute into the cell wall, presumably from cell lumen deposits, in both ACQ- and micronized copper quat-treated samples after exposure to high temperature and relative humidity. In a non-accelerated test, copper was not found to re-distribute into the cell wall in either ACQ- or micronized copper quat-treated samples after exposure in soil at 15°C for eight weeks.
R Stirling, J Drummond
A comparison of the chemistry of alkaline copper and micronized copper treated wood
2010 - IRG/WP 10-30528
This paper discusses the chemistry of the reaction of alkaline copper and micronized copper with wood. The objective of this study is to examine the copper species produced in wood during the fixation reaction using electron paramagnetic resonance (EPR) spectroscopy. The initial experiments (phases 1 to 2) were designed to confirm the effect of time of treatment and solution concentration on the spectral parameters of copper in sawdust treated with copper sulphate solutions. The relative ease of distinguishing the copper produced from alkaline copper treatments with those produced during treatment of aqueous copper solutions was the focus of phase 3 while phase 4 examined the chemistry of sawdust treated with aqueous suspensions of copper carbonate. In the final phase, the focus was on determining whether a soluble copper species could be identified in wood treated with micronized copper preservatives. The spectra were compared to those of sawdust treated with aqueous suspensions of basic copper carbonate. The results of the study clearly show that soluble copper is produced relatively rapidly in wood treated with aqueous suspensions of basic copper carbonate and that this copper reacts with wood to produce similar copper complexes to that formed between wood and copper sulphate. These copper complexes resist leaching. This would support the premise that soluble copper formed by the reaction between basic copper carbonate and wood, can migrate into the wood cell wall in a manner similar to other soluble copper chemicals, and bind to wood cell components. Further research is in progress to further identify the chemistry of these reactions.
Wei Xue, P Kennepohl, J N R Ruddick
Evaluation of ACQ-D treated Chinese fir and Mongolian Scots pine with different post-treatments after 20 months of exposure
2010 - IRG/WP 10-30530
The performance of alkaline copper quat-type D (ACQ-D) treated Chinese fir (Cunninghamia lanceolata Hook.) and Mongolian Scots pine (Pinus sylvestris Linn. var. mongolica Litv.) stakes after 20 months exposure in Chengdu and Guangzhou of southern China were evaluated according to AWPA standard E07-07. The ACQ-D treatments used two concentration levels (0.5 and 1.0%) and four different post-treatments (air drying for 1 month, conditioning at 70°C, 80% R.H. for 24h, oven drying at 110°C for 24h, boiling in water for 15h), respectively. The field test results showed that the natural durability of Chinese fir is a little better than Mongolian Scots pine but the untreated sapwood stakes of both wood species were mostly destroyed after 20 months exposure. After ACQ-D treatment, the sapwood of both wood species showed much better biological performance. Among the four post-treatments, the oven drying method (OD) rated the worst by showing slight reduction in biological performance and the most obvious reduction in compression strength after exposure, while the other three post-treatments performed similarly. It suggested that both post-treatments of HC (conditioning in humidity chamber) and HW (hot water bath) could be good selections for accelerating copper fixation in ACQ-D treated wood. And also, Chinese fir from plantation forests could be a potential wood species for preservation.
Lili Yu, Jinzhen Cao, Wei Gao, Haitao Su
A comparison of the corrosion of alkaline copper and micronized copper treated wood
2010 - IRG/WP 10-40515
With the replacement of chromate copper arsenate (CCA) by alkaline copper wood preservatives, there have been reports of increasing corrosion of metal fasteners and connectors in contact with treated wood. This may be explained by the presence of more mobile copper in the treated wood. One novel industrial response has been to develop a wood preservative based on an aqueous solution containing suspended basic copper carbonate and a co-biocide. This micronized copper preservative relies on the basic acidity of wood to release the copper which can complex with the wood components. As a consequence of the lower amount of mobile copper, the degree of corrosion should be significantly lowered, compared to the corresponding alkaline copper preservatives. The objective of this study is to examine the relative corrosiveness of micronized copper and alkaline copper treated wood to determine whether a significant reduction in corrosiveness is obtained. The interim results of the study have confirmed a significant reduction in the degree of corrosion on hot dipped galvanized fasteners as well as a lower rate of corrosion on bright (or common iron) fasteners. The levels of the corrosion of the micronized copper treated wood were similar to those observed for western red cedar, a durable wood that has been used in the past for decks and fences in British Columbia.
M Kofoed, J N R Ruddick
Combined effects of thermal modification and ACQ-D impregnation on properties of southern yellow pine wood
2013 - IRG/WP 13-40637
In this study, samples of southern yellow pine sapwood were first thermally modified and then treated by the alkaline copper quat-type D (ACQ-D) wood preservative. Two heating temperature (180℃ and 220℃) and two concentrations of ACQ-D solution (0.9% and 1.35%) were used in the experiments. The combined effects of thermal modification and ACQ-D on leaching performance, mechanical properties and mold resistance of the treated wood were then investigated. The results of the experiments indicated that thermal modification increased the percentage of copper leaching and decreased the MOR and MOE of wood, and also it affected the compression strength parallel to grain. After the ACQ-D impregnation, the bending properties of thermally modified wood got lowered to some extent. The anti-mold experiment indicated that the ACQ-D impregnation could improve the mold resistance of thermally modified wood.
Wang Wang, Yuan Zhu, Jinzhen Cao
Three-year field test of preservative-treated Canadian species in Korea
2014 - IRG/WP 14-30646
The purpose of this study was to generate field performance data in Korea on Canadian softwood species preservative-treated to Canadian standards. Two field tests of preservative-treated Canadian softwood species, one in ground contact and one above ground, were installed in Jinju, Korea in November 2010. Western hemlock and white spruce were incised and pressure-treated with alkaline copper quaternary (ACQ) or copper azole (CA), based on the Canadian CSA O80 Series-08 standards. End-matched material for ground contact exposure only was also installed in September 2011 at a field test site in Canada. After three years of exposure in Korea and two years in Canada, no decay was found in preservative-treated samples at either test site, while in untreated material decay, and particularly termite attack in Korea, were well advanced.
Jieying Wang, Jong Bum Ra, P I Morris
Effect of exposure site on metal migration from copper azole, alkaline copper quat or chromated copper arsenate treated southern pine decking
2015 - IRG/WP 15-50313
Metal migration from chromated copper arsenate, copper azole or alkaline copper quaternary compound treated southern pine lumber was assessed at sites in Mississippi and Oregon. Metal levels tended to be consistently higher in decks exposed in Mississippi. Rainfall characteristics did differ slightly at the two sites, but the levels did not appear to be of a magnitude that might affect metal mobility. The results suggest that tests of methods for limiting preservative migration from treated wood must expose materials at multiple sites to ensure that the processes are broadly appropriate.
J J Morrell, H M Barnes
Overview of the treated wood quality control program in the United States with the recent challenges and advances
2017 - IRG/WP 17-20616
In the past two decades, there have been significant and rapid changes in wood protection technologies for residential applications which have moved away from long established heavy duty metal oxide based products such as chromated copper arsenate (CCA). The successor generation of wood protection systems usually contain copper as the primary biocide, in combination with carbon-based co-biocides such as quaternary ammonium compounds (Quat), and/or triazoles (Tebuconazole and/or Propiconazole). The most recent developments have given rise to even more complicated combinations including multiple carbon-based biocides formulated in the form of emulsions or dispersions with or without water repellents or polymers aiming to minimize the use of heavy metals as well as provide improvement in wood dimensional stability and surface weathering performance. Also, long developed non-biocidal wood modification treatments, such as acetylation, thermal modification, furfurylation and hydrocarbon wax/oil treated wood have finally gained more commercial traction in the market place, especially in Europe. These new developments have challenged the industry to develop and use appropriate methods in order to meet the quality control (QC) standards and requirements in respect to concentration of treatment solutions, as well as chemical retention and penetration in treated wood. In the US, the QC system for treated wood product includes three key elements: treating plant internal QC for treating solution, treated wood, and treatment process; QC assistance and monitoring by the chemical/technological suppliers for their customers, and QC inspection by third-party inspection agencies. The enforcement of the QC standards through this comprehensive system is essential to ensure the performance of the treated wood products, the validity of product warranty program, and ultimately for the protection of consumers and the public. This paper overviews the US’s current QC standards and procedures used by treating plants, suppliers and independent inspection agencies. The chemistry challenges with the recent developments of multi-component systems and complex wood protection technologies, and their impacts on quality control methods are also discussed. Case studies have been used to illustrate how some of these challenges can and have been successfully addressed.
Preliminary study of the fungicidal and structural variability in copper naphthenates and naphthenic acids
1996 - IRG/WP 96-30114
Copper naphthenates, an oil-borne wood preservative listed by the American Wood-Preservers' Association (AWPA), is manufactured by complexing copper(II) with naphthenic acids. Prior to AWPA listing as a wood preservative, field experiments showed that copper naphthenates generally had good stability and were active against wood-destroying organisms. Recently, however, there have been reports of some copper naphthenate-treated poles rapidly failing. One possible explanation for the varying effectiveness could be that the structure, and resulting biological activity, of the naphthenic acids used to make copper naphthenate may vary. To test this hypothesis several naphthenic acids and copper naphenates were obtained and their fungicidal activity against three wood-destroying fungi measured. In addition, the chemical structure of the naphthenic acids were examined by proton- and carbon- NMR. Different activities were observed, especially against a copper-tolerant fungus. Some apparent correlations were seen between the fungicidal activity and chemical structures for the few samples studied.
T Schultz, D D Nicholas, L L Ingram Jr, T H Fisher
Sequestration of copper ions by the extracellular mucilaginous material (ECMM) of two wood rotting basidiomycetes
2004 - IRG/WP 04-10533
The radial growth rate of colonies originating from either whole or ECMM-free inocula of Coriolus versicolor was investigated. The presence of ECMM allowed colonies to maintain higher growth rates than those form ECMM-free inocula up to 2 mM CuSO4 in the medium. The ECMM of C. versicolor and G. trabeum was able to reduce the diffusion of copper ions in solution. The ‘raw’ ECMM of both fungi had a greater ability to reduce the diffusion of copper ions than ECMM which had been subject to dialysis to remove soluble, low molecular weight components. The ‘insoluble’ fraction of ECMM for both species was more effective than the ‘soluble’ fraction at reducing the diffusion of copper ions. It is concluded that ECMM confers some protection to hyphae against the toxic effects of copper ions on growth in vivo and that this due to the binding of copper ions to both the polysaccharide and to low molecular weight components of the ECMM
D Vesentini, D J Dickinson, R J Murphy
Influence of different fixation and ageing procedures on the leaching behaviour of copper from selected wood preservatives in laboratory trials
2003 - IRG/WP 03-20264
The paper focuses on the role of different parameters, such as fixation, sample size, wood species, and leaching in internationally standardized ageing procedures for wood preservatives from Europe, Japan and the United States. The leaching protocols used were EN 84, JIS K 1571 and AWPA E11 protocols. The wood species were Scots pine, Sugi and Southern Yellow Pine respectively. Three types of commercially important copper-based wood preservatives were used as model formulations, namely copper/copper-HDO, ammoniacal copper/quat and CCA. The most important factors determining the extent of copper leaching in the different lab trials were the sample size (volume/surface ratio) and the fixation conditions prior to leaching. On the other hand, the wood species and the leaching protocol itself were found to have only minor influence on the copper leaching rate in the test methods included in this study.
J Habicht, D Häntzschel, J Wittenzellner
International collaborative laboratory comparison of two wood preservatives against subterranean termites: Third update and first report
1996 - IRG/WP 96-10174
At the 24th annual meeting of IRG in Orlando, USA, in May 1993 an international subterranean termite laboratory bioassay to compare the various preferred termite protocols used by IRG termitologists was initiated. The author was nominated to co-ordinate this comparative laboratory evaluation of two wood preservatives, copper-chrome-arsenic (CCA) and copper naphthenate (Cu-Na) against the subterranean termites used as test termites in Australia, France, Japan, Thailand, United Kingdom and the Unites States of America. Solutions of these two wood preservatives were prepared and impregnated into Pinus radiata wood blocks to obtain loading of 0.0, 0.5, 1.0, 2.0 and 4.0 kg/m³ respectively. All preservative treatments were carried out at the Division of Forestry and Forest Products in Melbourne. The treated specimens were dispatched to the participating researchers who subjected these specimens to attack by their test termite species, and have now returned the specimens to Melbourne. This paper reports the amount of wood consumed and the mean mass loss (%) on both treated and untreated wood blocks by the termites in the various laboratory bioassays.
J R J French
Types of decay observed in CCA-treated pine posts in horticultural situations in New Zealand
1984 - IRG/WP 1226
The few reported failures of 11-12-year-old horticultural posts in New Zealand in 1982 were caused by brown-rot. A subsequent survey of CCA-treated posts in all the major horticultural areas has revealed decay of many posts. A microscopic examination of these posts has shown decay by brown-rot, white-rot, soft-rot and bacteria. Several types of bacterial decay have been observed.
J A Drysdale, M E Hedley
An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper-chrome-arsenic preservative
1981 - IRG/WP 3150
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. We have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins
Electrodialytic remediation of creosote and CCA treated timber wastes
2002 - IRG/WP 02-50190
There is a growing concern about the environmental issue of impregnated timber waste management, since an increase in the amount of waste of treated wood is expected over the next decades. Presently, no well-documented treatment technique is yet available for this type of waste. Alternative options concerning the disposal of treated wood are becoming more attractive to study, especially the ones that may promote its re-use. Inside this approach, the electrodialytic process (ED) seems a promising technique for removal of preservative chemicals from treated wood waste. The method uses a direct electric current and its effects in the matrix as the “cleaning agent”, combining the electrokinetic movement (mainly due to electromigration, but also electro-osmosis and electrophoresis), with the principle of electrodialysis. This work reports results from the application of the electrodialytic process to an out-of-service Portuguese creosote and CCA-treated Pinus pinaster Ait. railway sleeper and pole. The behaviour of the process is described and the main results discussed. The average removal rate, estimated in accordance with prEN 12490, for creosote from treated timber waste was around 40 %.. For CCA treated timber waste, experimental conditions that could optimise the process efficiency (e.g. current density, time) were studied. The highest removal rates obtained until now, in our studies, were 93 % of Cu, 95 % of Cr and 99 % of As for sawdust using 2.5 % oxalic acid (w/w) as the assisting agent. For CCA treated wood waste in the form of chips, the best removal rates obtained until now were 84 % of Cu, 91 % of Cr and 97 % of As.
E P Mateus, A B Ribeiro, L Ottosen
Fungicidal activity of some organic solvents, copper carboxylates and their complexes with 2-aminoethanol
1997 - IRG/WP 97-30136
We evaluated the activity of eight organic solvents against wood - rotting fungus Trametes versicolor in order to choose the most appropriate one for rapid screening tests of some copper(II) carboxylates and their adducts with 2-aminoethanol. Their activity against the selected fungus was classified in the following order: chloroform > N,N-dimethylformamide > acetonitrile > methanol > dimethyl sulfoxide > ethanol > acetone. The non-polar white spirit did not dissolve in the growth medium and the results could not be directly compared with the results for other solvents. As an appropriate solvent for screening of the tested copper(II) carboxylates, dimethyl sulfoxide (DMSO) was chosen. Minimal inhibitory concentration against Trametes versicolor of the screened carboxylates was in the concentration range of 1x10-4 to 1x10-3 mol/l. Coordinated amine ligands slightly, and not significantly, decreased fungicidal properties of the tested carboxylates.
M Petric, F Pohleven
Termite resistance of pine wood treated with chromated copper arsenates
1997 - IRG/WP 97-30128
Two four-week, no-choice laboratory tests were performed with CCA-treated southern yellow pine and radiata pine against Formosan subterranean termites, Coptotermes formosanus. CCA retentions as low as 0.05 kg/m3 (0.03 pcf) provided protection from all but light termite attack (rating of 9 on a 10-point visual scale). Similar and consistent light attack on wafers containing retentions as high as 6.4 kg/m3 (0.4 pcf), coupled with complete termite mortality, demonstrates that the mode of action of CCA treatments relies upon toxicity rather than having any repellent effects against termites.
J K Grace