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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

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

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 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

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

A survey of the incidence of decay in copper-chrome-arsenate treated trellis support posts used in horticulture in New Zealand
1984 - IRG/WP 1225
Copper-chrom-arsenate treated softwood posts used as trellis support structures in 5 major horticultural districts of New Zealand were systematically examined for presence of decay. Principal crops on properties examined were grapes and kiwifruit; a minority of properties grew hops, boysenberries, and dwarf apples. Occurrence and severity of decay were variable within specific age classes of posts on individual properties and also between properties in the same region which had posts of similar age. Incidence of decay was higher in posts set in soils which were highly moisture retentive than in posts in drier areas or set in freely draining soils. Cross-sectional size and age of posts showed little correlation with frequency of severe decay, although the percentage of posts free of decay increased with decreasing age.
M E Hedley, J A Drysdale

Effect of treatment process on performance of copper-chrome-arsenate. Part 1: Fungus cellar tests
1995 - IRG/WP 95-40045
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, fungus cellar stakelets, 5 x 10 x 180 mm³ were cut from treated material and after leaching were exposed in unsterile soil beds in the FRI Fungus Cellar. Results after 65 months' exposure indicate that performance was related only to preservative retention. Differences in treatment process had little effect on decay resistance. This is in contrast to results from pure culture decay tests, reported earlier, which indicated that disproportionation of preservative elements using empty cell processes and low preservative concentrations had significant effect on durability.
M E Hedley, J Anderson, J B Foster, B E Patterson

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

The micro-distribution of copper/chrome/arsenate in Acer pseudoplatanus and Eucalyptus maculata
1973 - IRG/WP 319
The excellent field performance of copper-chrome-arsenate (CCA) treated timber has been accepted for many years. The preservative loadings used in practice have been based on field trial results, backed by service tests. The performance of treated hardwoods in trials and practice indicated that provided the required loading and penetration could be achieved the performance would be good. Recent unexpected failures in a few hardwoods treated to specification indicate that some hardwoods behave differently in ground contact from the normal test species with equal preservative loadings. Field evidence with creosote suggests that some discrepancies can occur with other preservatives as well. The immediate problem is confined to a vary few species and in all cases failure has been due to soft-rot at the ground line. Petty & Preston (1968) demonstrated that CCA preservatives penetrate deeply into the tracheid wall of conifers affording excellent protection to the timber. It was decided to investigate the micro-distribution of CCA preservative components in two problem hardwood species, Acer pseudoplatanus and Eucalyptus maculata. If the components were found to be distributed less uniformly than in softwood tissues this could possibly account for the unexpected field performance of these hardwoods in ground contact.
D J Dickinson

The effects of pH on leaching of copper-chrome-arsenate (CCA) from pressure-treated Kenyan-grown Eucalyptus saligna and Acacia mearnsii: Initial findings.
2002 - IRG/WP 02-30298
The effects of pH on leaching of CCA from pressure-treated Kenyan-grown Eucalyptus saligna and Acacia mearnsii were tested under laboratory conditions. Small samples of the two species (100mm x 30mm x 40mm) were smooth sawn from 8-year old trees to represent equal amounts of both sapwood and heartwood, air-dried to 12% moisture content, end-sealed, and pressure-treated at a commercial treatment plant (6% CCA-C oxide type). They were then conditioned and air-dried to 12% moisture content and average retentions for each species calculated, (18.2Kg/M3 for eucalyptus and 17.3Kg/M3 for acacia). Batches of samples of each species were then separately leached for 3, 6, 9, 12, 15, 18, and 21 days in tap water, with the pH adjusted to 3.0, 6.0, and 8.0. After each leaching regime samples were removed, oven-dried to 12% moisture content, and the amount of CCA leached out calculated on a weight loss basis. The results revealed that, after 21 days, leaching of CCA from the two species was highest at pH 3.0 (9.8Kg/M3 or 53.8% for E. saligna; 10.2Kg/M3 or 58.4% for A. mearnsii). Lower amounts of CCA were leached at pH 8.0 after 21 days, 5.5Kg/M3 or 30.2% for E. saligna and 6.0Kg/M3 or 34.1% for A. mearnsii. Leaching after 21 days was lowest at pH 6.0, 4.4Kg/M3 or 24.2% for E.saligna, and 3.0Kg/M3 or 17.3% for A. mearnsii. For each of the pH level tested, both species appeared to lose more CCA during the firsts 12 days of leaching, amounts being then lower up to 21 days. The results indicated that CCA-treated poles and posts of E. saligna and A. mearnsii are likely to suffer from excessive preservative depletion, especially when used in acidic soils, leading to short service lives. Further investigations are necessary to establish whether depletion of CCA from these two species may be due to high lignin and tannin contents, or inappropriate treatment techniques.
R Venkatasamy

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

Can CCA be substituted as reference preservative?
2018 - IRG/WP 18-20641
While field testing of wood protective formulations remains probably the best method to find out the effective preservative concentration, the use of chrome-copper arsenate (CCA) as reference becomes debatable due to environmental and legislative reasons. This emerges from the European standardization bodies who have discussed reference alternatives that can omit the use of CCA. The present debate article suggests one possible approach to cope with the problem. CCA has served in the tests fields of the Nordic countries for more than 50 years and thus, offers a solid database for modelling of its behaviour and service life in in-ground conditions. Based on data from the field of Simlångsdalen (Sweden), this paper outlines a simple but reliable model that can substitute the use of CCA. Seventeen tests were included into the model; some extremes, i.e. very short or long test durations were discarded. Statistical analysis shows that both logarithmic and linear regressions can describe the decay index in a similar way. Some applications of the model to real test data that the Technical Group at the Nordic Wood Protection Council works with have been compared to the standard method based on the European standard EN 599-1. Results demonstrated that the model generates similar data of formulation concentrations compared to the standard method. It is suggested that identical models, based on data from the other Nordic fields, could be developed and applied. The proposed method demands a wide discussion between the testing and standardization bodies for further practical implementation.
N Terziev, M Jebrane, P Larsson Brelid, N Morsing, P-O Flaete, P Torniainen, J S Kim, G Daniel

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

An introduction to environmental aspects of groundwater arsenic and CCA treated wood poles in Bangladesh
1997 - IRG/WP 97-50081
The environment comprises biosphere, lithosphere, atmosphere and hydrosphere. Therefore, environmental science is a multi-disciplinary study, includes life sciences, physical sciences, chemical sciences, geology, geography, meteorology, forestry, agriculture, soil science, hydrology, ecology, public health, engineering etc. Tremendous industrial and mining activities, deforestation and population explosion are threatening the very existence of life on earth.Groundwater is used for irrigation, drinking and other domestic purposes where other sources of water are not plenty. Groundwater contain different metals resulting from soluble minerals, deposited in ground during its origin. Thus concentration of metals in surface soils and water are increased day by day by lifting of groundwater. Surface soils and water also receive metals from industries and mines and as a result of multipurpose use of products from those. Deforestation is controlled by plantation and preservation of forest products by different wood preservatives. Recently groundwater in some underground rocks of Tertiary and Quarternary age in Bangladesh is very often known to contain arsenic (As) above permissible limits . On the other hand chromated copper arsenate (CCA) impregnated wooden poles has been used for rural electrification in Bangladesh since 1979. It is an attempt to find out through research and review of literatures that whether the groundwater As is contaminatable from As used in wood poles and whether the components of CCA cause environmental problems. Possible way of purification of arsenic containing groundwater for drinking have been suggested.
A K Lahiry

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

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

Performance of chromated copper arsenate-treated aspen fence posts installed in Forintek's Eastern test plot from 1951 to 1963
1984 - IRG/WP 3272
Aspen poplar fence posts were pressure treated by the full cell process using three formulations of copper chrome arsenate wood preservative. A total of one hundred and fifty nine of the posts were installed in service in Forintek's Chalk River post plot from 1951 to 1962. During the 1982 general inspection of the post plot all 159 posts were still in service. A groundline inspection was carried out on the material to determine the extent to which decay had progressed during this period. Samples were taken from the surface of tanalith C treated posts and subsequent microscopic examination revealed that soft rot attack was present in the outer portion of posts. The groundline area of posts treated with (K 33), CCA type B and (greensalt) CCA type A were in generally good condition after 22 years and 31 years respectively. Rate of decay was highest for CCA-C tanalith treated posts at 0.3 mm per year with a retention of 3.04 kg/m³ oxides.
C D Ralph

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

Treatability of Siberian larch and spruce with chromated copper arsenate
1996 - IRG/WP 96-40060
Heartwood of Siberian larch (Larix gmelini) and spruce (Picea jezoensis) was pressure treated with chromated copper arsenate (CCA) Type B using a full cell process. Larch heartwood was somewhat difficult to treat than the spruce, although both species did not meet a minimum requirements of penetration and retention specified by the American Wood Preservers' Association (AWPA) for difficult to treat wood species in ground contact. To improve the preservative treatability of refractory larch and spruce, end matched heartwood lumber had been incised using either a conventional or a double density incising pattern, and then pressure treated with CCA Type B. The use of double density incising is necessary for spruce heartwood in order to acheive adequate treatment with CCA; however, the increase in incision densities and/or the use of high treating pressure may be required for adequate treatment of larch heartwood.
Gyu-Hyeok Kim, Woo-Gue Jee, Jae-Jin Kim

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

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

A Soil Bed Test of the Effect of CCA Penetration on the Performance of Hem-fir Plywood
2004 - IRG/WP 04-30332
An accelerated decay test was set up to compare the performance of CCA-treated Western hemlock/amabilis fir plywood treated to meet the preserved wood foundation (PWF) retention standard with various patterns of preservative penetration. Short lengths of treated plywood and comparable untreated material were installed in a soil bed. After eleven years of exposure, the CCA treatments were all sound regardless of penetration, while the untreated material had failed due to decay within three years.
P I Morris, J K Ingram

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