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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

The leaching of copper, chrome and arsenate from CCA-impregnated poles stored for ten years in running water
1978 - IRG/WP 3122
There is no evidence to indicate that the chromium and copper components are leached from the outermost 5 mm of sapwood in poles impregnated with Boliden K33 and Tanalith C and stored in running water for ten years. The arsenic component, however, seems to be leached out during the first few months to an extent of about 20% of the initial amount. The leaching time is dependent on the preservative used.
F G Evans

Proposed test procedure to determine the effect of timber substrate on the effectiveness of a copper/chrome/arsenic preservative in seawater
1975 - IRG/WP 411
R A Eaton

A study of salt imbalances observed in recycled copper/chrome/arsenic preservative solutions in commercial practice
1987 - IRG/WP 3461
The study reported monitored tank solutions, sludge and other by-products using a standard CCA solution, when recycled. This recycling of the CCA solution is quite usual in between any commercial treatment schedules. Salt imbalances were observed and the possible reasons for such phenomena were studied. The paper discusses the procedure followed, the method of sampling the liquid after the charge and the analysis, to arrive finally at an aggregation and conclusion from the data.
V R Sonti, S Sonti, B Chatterjee

Fungi associated with groundline soft rot decay in copper/chrome/arsenic treated heartwood utility poles of Malaysian hardwoods
1992 - IRG/WP 92-1567
Copper-chrome-arsenic treated heartwood from Malaysian hardwood utility poles in service for 8-23 y at two localities in the wet tropical Peninsula Malaysia were surveyed for soft rot in the ground-contact region. Soft rot decay was detected in all the poles. Isolation studies indicated the ability of a variety of microfungi and basidiomycetes to colonize treated heartwood. Most isolates exhibited variable soft rot ability based on a combination of soft rot tests. A few of the isolates formed soft rot cavities (decay types 1 & 2) and belonged to genera previously found associated with soft rot decay. In particular, isolates of Chaetomium globosum and Phialophora occurred frequently on the surface of sampled poles, while Paecilomyces variotii occurred at all sampling depths from the wood surface. It appeared that soft rotting ability of selected isolates (determined from both mass loss and dilute alkali solubility of degraded native cellulose) was affected by the choice of incubation temperatures.
A H H Wong, R B Pearce, S C Watkinson

X-ray analysis of selected anatomical structures in copper/chrome/arsenic treated wood
1973 - IRG/WP 320
Application of analytical electron microscopy to problems in wood preservation has been very limited. Indeed, less than ten workers appear to have published their results using the technique, and of these' only two papers deal with energy dispersion procedures in the scanning electron microscope; the others employ the more familiar wavelength dispersive methods of the electron probe.
H Greaves

A laboratory soil-block decay evaluation of plywoods edge-treated with preservatives
1982 - IRG/WP 2174
Preservative-treated plywood used under conditions or severe decay hazard frequently has its original, or cut edges, protected by the application of a field-cut preservative. This study uses a laboratory test method to compare the efficacy of four commercial preservative treatments against two commonly occurring brown-rot fungi. The results are not meant to indicate the service life of such treated plywood.
R S Smith, A Byrne

Interaction mechanisms of F/Cr/As/B type preservative and wood
1981 - IRG/WP 3183
The paper reports results of investigations on the fixation of the components of a F/Cr/As/B preservative in wood and its lignin and cellulosic components.
N Ermush, I Andersone

Retention and distribution of copper/chrome/arsenic (CCA) in pressurised sap-displaced UK grown spruce and pine
1986 - IRG/WP 3366
Increment cores were taken from UK grown Scots pine (Pinus sylvestris L.), Corsican pine (Pinus nigra var. maritima Ait), Sitka Spruce (Picea sitchensis (Bong) Carr), and Norway spruce (Picea abies (L) Karst) distribution poles treated by pressurised sap-displacement using a 1.8% copper, chrome, arsenic (CCA) solution. Each increment core was sectioned radially and the copper, chrome, and arsenic content analysed. All four wood species showed a higher CCA content in the outer sapwood which declined radially towards the centre of the pole. The net preservative retention in the outer sapwood of Scots Pine, Corsican Pine and Norway Spruce was in the range 13-23 kg/m³. The CCA content in the outer sapwood for Sitka spruce was low (in the range 4-7 kg/m³). Little longitudinal variation in CCA content occurred along the length of the poles for the four wood species studied. The concentration of the individual CCA components varied in a radial direction. Chrome and Arsenic concentrations were at a maximum in the outer sapwood in all four wood species whereas Copper tended to be in a maximum concentration in the inner sapwood some 20-40 mm from the pole surface. This effect was particularly noticeable in Scots pine and Corsican pine. It is believed that the preservative gradients reported may be important in determining the performance of treated wood and as such should be taken into account when designing predictive tests of the efficacy of preservative treatments.
P D Evans, G M Smith, B King

The volatilization of arsenic on burning copper-chrome-arsenic (CCA) treated wood
1978 - IRG/WP 3111
Small scale burning experiments are described involving copper-chrome-arsenic treated wood. Approximately 20 per cent of the arsenic was volatilised when the wood was burned in air but 60 per cent when burned in an oxygen-enriched atmosphere, this increase is attributed to an increase in combustion temperature. Although a small increase in arsenic evolution was found with an increased concentration of CCA in the wood this increase is not considered sufficient to be of any practical importance. The concentration of water-soluble arsenic and chromium in the wood-ash was greater when the experiment was conducted with oxygen-enriched air.
A-J Dobbs, C Grant

The dip diffusion treatment of tropical building timbers in Papua New Guinea
1972 - IRG/WP 310
In Papua New Guinea a dip diffusion process using a multi salt preservative developed by C.S.I.R.0. has been in commercial use for 8 years. Over 200 million super feet (236,000 m³ ) of timber has been treated during this period and current rate of treatment is 34 million super feet (80,400 m³ ) of timber per year in 70 licenced treatment plants. The process has been found to be simple to apply, convenient to control and has proved very successful in the protection of timber used out of ground contact and protected from the rain. No serious health hazards to process operators or product users have come to light. In common with other countries in the wet tropics P.N.G. is faced with very serious biological deterioration hazards to timber in houses but dip diffusion has overcome the major problems. During the 16 years in which dip diffused timber has been in service in P.N.G. there have been no notable falldowns, the only falldowns reported being in mouldings in which heavy dressing has removed the preservative envelope, but this is a very rare occurrence and cannot be considered of economic importance.
C R Levy, S J Colwell, K A Garbutt

Effect of treatment process on performance of copper-chrome-arsenate. Part 2: Field stake tests
1995 - IRG/WP 95-40046
Pinus radiata sapwood stakes 20 x 20 x 400 mm³ were treated with CCA Type C using a range of concentrations and three treatment processes; Bethell, Lowry and Rueping. Preservative retention was determined by chemical analysis of treated material. Following fixation stakes were installed in a randomised plot in the Whaka graveyard located on the FRI campus. Stakes were inspected at yearly intervals using AWPA M-10 standard procedure. After 5 years' exposure performance was strongly correlated with preservative retention expressed either as copper retention or total element (Cu+Cr+As) retention. Treatment process had very little effect on performance and confirmed results obtained from similar material exposed in fungus cellar tests. Implications of these results for commercial treatment operations are discussed.
M E Hedley, J Anderson, J B Foster, B E Patterson

Preliminary study on relation of wood structure to copper/chrome/arsenic (CCA) distribution in kempas (Koompassia malaccensis)
1995 - IRG/WP 95-40054
Kempas had been treated with copper/chrome/arsenic (CCA) preservative using full cell process. Analysis of preservative distribution at the micro level in relation to wood structure was carried out using scanning electron microscope (SEM) and energy dispersive X-ray (EDXA) analysis. The results showed that CCA elements were detected in all wood tissues at different ratios. Distribution of chemical elements appeared to be much greater in the tangential longitudinal section (TLS) than the transverse section (TS). Though the amount of chemical elements had not been quantified from the radial longitudinal section (RLS), the SEM observations showed a high distribution of chemical precipitate. In all the wood tissues observed, Cr appeared in highest amount. The precipitate analysed by EDXA, showed As in greater amount than Cr or Cu. Silica content was highest in fibres and rays as determined by EDXA but could not be detected in structural form under SEM or light microscope.
S Ani, S Salamah

Sampling variation in a copper chrome arsenic treated power transmission pole
1990 - IRG/WP 2351
The Queensland Forest Service routinely samples poles treated at all treatment plants throughout the State. Each treatment plant is issued with a Certificate of Registration and the accompanying documents list the different levels of preservative retention required for performance in various service conditions. The posted levels represent the.minimum permissible, and it is to these concentrations of preservative that a piece of treated timber is tested. All samples taken must pass the required level of treatment. Because minimum levels are used, it is important to ensure that any samples taken are representative of the whole piece. A plug sample taken from a pole is 19 mm in diameter by the depth of the sapwood long. The 'analytical zone' is the inner 1/3 of the sapwood band closest to the truewood and the size of the 'analytical zone' varies with the thickness of sapwood. Analyses were carried out on a number of plug samples from a preservative treated power pole, to examine the variation in preservative retention that can occur when samples are taken from different locations along the pole.
J Norton

Leaching and fixation characteristics of chrome-copper-fluoride-zinc (CCFZ) treated wood
1996 - IRG/WP 96-30096
The leaching characteristics of radiata pine sapwood blocks treated with CCFZ were evaluated by the AWPA standard leaching test. The rate of fixation of the preservative components in CCFZ treated radiata pine were also evaluated by quantitative analysis of solution expressed from the treated wood. Both leaching and fixation characteristics of CCFZ were compared with CCA-Type C treated wood samples. The permanence of CCFZ is excellent and comparable to that of CCA-Type C, and the rates of CCFZ fixation were similar to those found for CCA-Type C. These results suggest that CCFZ has a potential as alternative preservative for the replacement of CCA-Type C.
Gyu-Hyeok Kim, Jong-Bum Ra

Preliminary studies on cellulase production by selected Basidiomycetes and the effect of copper-chrome-arsenate on these enzymes
1980 - IRG/WP 1122
The growth of wood-destroying fungi on ligno-cellulosic materials depends on the production of many enzymes, of which probably the most important is the multi component cellulase system. Within this system, at least three different kinds of enzym are believed to be involved in crystalline cellulose decomposition. These are endo-1,4-glucanase, exo-1,4-ß glucanase and ß-glucosidase. Most of the recent research on cellulases has concerned isolation, purification and characterisation of the enzymes and their application in the utilisation of cellulosic waste. Information on the chemical inhibition of cellulases is available but there is little reference to the interaction of wood-attacking cellulases and the preservatives which are used to protect wood. The objective of this work is to study the production and activity of cellulases of selected basidiomycetes and to observe the effect of wood-preservatives on these enzymes. Preliminary studies with copper-chrome-arsenate (CCA) are reported here
O Collett

Effectiveness of copper/chromium salts as wood preservatives against Limnoria tripunctata Menzies in laboratory tests
1977 - IRG/WP 431
During the last joint meeting of IRG and COIPM a co-operative programme of tests with copper/chromium salts as wood preservatives against marine borers was discussed and agreed. In this connection the results of a laboratory test in the BAM with Limnoria tripunctata Menzies will be of interest. But as the respective paper is written in German (H. Kühne; G. Becker: Laboratoriumsversuche über die Wirkung kupferhaltiger Schutzsalzgemische auf die Holzbohrassel Limnoria tripunctata Menzies) (Material u. Organismen 5 (1970) No 4, 307-319) a comprehensive summary is given in English for IRG-COIPM members.
H Kühne

Safe application of copper-chrome-arsenate preservatives
1975 - IRG/WP 377
All wood preservatives contain biologically active substances and must, by design, be in some measure toxic to man. There is nothing fundamentally difficult, however, about using a wood preservative with complete safety. It depends on knowing the risks to health and/or the environment, which the preservative may present, and planning application accordingly. In this paper we examine these and other factors for copper-chrome-arsenate (CCA) preservatives applied in vacuum/pressure plants. We review briefly the toxicological properties of the components and their joint action; the contribution which design and the operation of plant make to safe treatment; also the training of plant operators, to ensure that the potential risks in applying CCAs are fully understood. We shall consider the functions of product labelling; to advisc others - concerned with transport - of the nature of preservatives, especially concentrates. The importance is emphasised of being able, by prior planning, to act swiftly and effectively to deal with any unforeseen emergencies, however infrequent these may be. This paper is not concerned with any risks to man and other animals arising from use of CCA-treated wood. After treatment, fixation leaves the preservative components less readily available as contaminants of the environment.
I N Stalker, P B Cornwell

The influence of soil pH on leaching of CCA elements from pressure-treated Eucalyptus saligna sapwood: environmental implication
2003 - IRG/WP 03-50203
Evidence is accumulating as to poor distribution and fixation of CCA in tropical hardwoods, and there is therefore a necessity to investigate the permanency of CCA in tropical hardwoods. The relationship between soil pH and leaching of Cu, Cr and As from CCA pressure-treated sapwood of Kenyan-grown Eucalyptus saligna was tested under laboratory conditions. Small sapwood samples were pressure-treated with 6% CCA-C (oxide type) to a retention of 25.4 Kg/m3, and leached with mild agitation in soil-extract water representative of soil pH 3.5, 4.5, 5.0, 7.5, 8.5, and in tap water (pH 6.8), for 3, 6, 9, 12, 15 and 18 days under controlled laboratory conditions. The results revealed that leaching of Cu, Cr and As was generally high under acidic conditions, low under alkaline situations and lowest at neutral pH. After leaching for 18 days at pH 3.5, average extraction of Cu, Cr and As was respectively 60.8 ppm, 51.3 ppm and 53.8 ppm. Leaching at pH 6.8 extracted low average amounts of Cu, Cr and As, being 0.15 ppm, 0.25 ppm and 0.42 ppm respectively. At pH 8.5 losses were Cu: 1.9 ppm, Cr: 2.4 ppm and As: 1.4 ppm. The patterns of leaching of the elements were irregular in relation to pH and the order established after 18 days of leaching was Cu>As>Cr at pH 3.5, As>Cr>Cu at pH 6.8 and Cr>Cu>As at pH 8.5. Apart from the influence of pH alone, the chemical, physical and microbiological properties of the soil-extract water used may also have influenced leaching. The results indicate that CCA-treated E. saligna used in ground contact, especially in acidic soils, may lose significant amounts of Cu, Cr and As to the environment. The environmental risks that the large number of CCA-treated hardwood poles and posts used in tropical soils represent raise the question as to whether CCA should remain the preferred wood preservative for tropical hardwoods, especially the eucalypts.
R Venkatasamy, D N Okwara

Soft rot test of copper/chrome/arsenic treated heartwood of three Malaysian timbers
1991 - IRG/WP 2381
Standardized heartwood blocks of kempas (Koompassia malaccensis), keruing (Dipterocarpus sp.) and tualang (Koompassia excelsa) were impregnated with 0 to 6.3% (w/v) CCA and challenged to decay by a mixed inocula of Chaetomium globosum, Glenospora graphii, Humicola grisea, Petriella setifera and Trichurus spiralis in a containerized vermiculite-burial decay system according to draft CEN/TC 38 WG 4. A similar burial test using unsterile garden soil was included for comparison. The results of a preliminary assessment of a 12 w experiment were recorded (IRG/WP/2354). Due to low mass losses and final block moisture contents after the standard 12 w incubation, the experiments were resumed with the same samples and the above outlined culture conditions. Untreated European beech wood (Fagus sylvatica L.) was included as reference species. The experiments continued until beech samples reached 25% mass loss in soil-burial test (36 w). Final results are presented and the adaptation of draft EN soft rot test for treated tropical hardwoods are discussed.
A H H Wong, R-D Peek

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 3180
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. The growth characteristics of spruces (Picea spp) make them attractive candidates for forestry schemes. In 1975 the UK Forestry Commission had about 400 000 hectares, about 20% of total UK forest area, planted with Sitka spruce (Picea sitchensis). As an example of the situation in Scandinavia, the growing stock in Sweden consists of about 45% Norway spruce (Picea abies), 38% Scots pine (Pinus sylvestris) and the remainder hardwoods. The importance of spruce as a source of sawn timber in Europe is clear and we are investigating methods of improving the treatment of this timber. As part of the investigation we have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins

Fixation of copper-chrome-arsenic treated timber: A comparison of leaching methodologies
1996 - IRG/WP 96-50075
Five packs of kiln dried radiata pine heartwood were treated with copper-chrome-arsenic preservative treated, utilising a modified Bethell treatment schedule. Two methods of determining the level of preservative fixation were compared. These included the diphenylcarbazide method and simulated rainfall testing. The fixation levels were generally higher for tests involving simulated rain leaching. Fixation of copper-chrome-arsenic determined by the diphenylcarbazide method was found to fluctuate with time. Localised surface concentrations of preservative, 'hot spots', were suggested as the cause. Simulated rainfall appeared to provide a more realistic assessment method for determining potential preservative leaching of multisalt preservatives.
S Walley, P R S Cobham, P Vinden

Relative performance of copper/chrome/boron (CCB) and copper/chrome/arsenate (CCA) in ground contact
1992 - IRG/WP 92-3694
The performance of four retentions each of an oxide CCA formulation and a salt formulation of CCB in radiata pine and European beech was compared after 18 years' field exposure. In radiata pine CCA oxide was more effective (4 failures out of 40) than CCB (9 failures out of 40). However, in European beech CCB was substantially more effective (22 failures) than CCA oxide (all failed). Analysis of failed stakes showed that up to 85% of arsenic had been lost from below ground portions of CCA oxide-treated beech stakes compared with 75% of boron from CCB-treated beech stakes. Percentage losses of copper and chromium were less.
M E Hedley

The mechanism of leaching of copper-chrome-arsenic preservatives from treated timber in saline waters
1976 - IRG/WP 374
A mechanism for the leaching of copper-chrome-arsenic preservatives is proposed on the basis of theoretical calculations and experimental studies using timber subjected to a range of water types of different ionic compositions. Complex formation by copper (II) and chromium (III) with chloride and hydroxide ions is shown to affect the leaching rate. Of even greater importance is the salt effect on the activity coefficients. The various complexes formed at different pH values are discussed. Two minima are observed in the plot of copper leaching versus water salinity; these are attributed to the presence of the copper fixation compounds Cu2(OH)AsO4 and Cu3(AsO4)2. At low salinities NaCl is shown to have a coagulating effect on the copper fixation compounds, reducing their solubility, whereas at higher salinities complex formation dominates. With chromium the coagulation effect is not observed and leaching increases with increasing salinity. Loss of arsenic is shown to lag behind that of copper and chromium and is related to the chromium excess in the preservative formula: the greater the excess, the longer the delay in arsenic loss. The suggested mechanism adequately explains the experimental results.
J Irvine, S-E Dahlgren

Distribution of copper/chrome/boron preservative in light red meranti (Shorea leprosula) before and after exposure test for 72 months
1995 - IRG/WP 95-20073
Copper/chrome/boron (CCB) preservative at 6% w/w was impregnated into light red meranti (Shorea leprosula) by full cell process. The quantitative analysis for copper, chrome and boron contents in treated wood samples was carried out by Inductive Couple Plasma (ICP). Electron Probe Microanalyser (EPMA) was used to monitor the distribution of copper, chrome and boron in the various treated wood tissues before and after exposure for 72 months.
S Salamah, S Ani

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