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Copper linoleate: A new low toxcity wide spectrum, heavy duty wood preservative
1995 - IRG/WP 95-30082
Copper linoleate, a "fixed" copper soap has been developed and evaluated in South Africa over a 30-year period. The initial product, an organic solvent based preservative has been tested in pine poles against termites and fungi. Results indiate that the product has performed well against existing heavy duty wood preservatives such as CCA and creosote in long term field trials (30 years). The paper describes the basic formulation of copper linoleate and the reaction and possible fixation mechanisms of copper linoleate with wood lignin. The paper moves on to describe further work on an emulsifiable version of copper linoleate for use as a water borne wood preservative. The performance of this product is evaluated in accelerated trials to obtain comparative performance data. The emulsion-based product addresses a need for a low-toxicity, waterborne, heavy duty wood preservative. The paper also considers some of the physical properties of the product and outines the remaining barriers for its industrial commercialisation.
D Conradie, P Turner, W E Conradie, A J Pendlebury, T Pizzi


Pest control products act. An overview of regulation of heavy duty wood preservatives
1995 - IRG/WP 95-50040-30
The regulation of pesticides in Canada is carried out under the authority of the Pest Control Products Act and Regulations. Products which control, prevent, destroy, mitigate, attract or repel a pest are required to undergo a presale assessment for safety, merit and value. This review will determine whether a product, when used according to label directions, can be used both safely and will be effective for controlling pest(s). Four federal government departments, Health and Welfare Canada, Environment Canada and Agriculture Canada, Natural Resources Canada, are involved in making timely and acceptable regulatory decisions on wood preservation products. Presently wood preservative products represent approximately four percent of the active ingredients contained in registered pesticide products and are registered for use areas such as pressure treatment, sapstain control, millwork and remedial applications. Requests for registration of new products are subjected to a rigorous assessment of health effects (both acute and long term) as well as environmental impact. The number and nature of studies requested is largely dependent upon the manner of intended use. There are several ways in which pesticides are regulated. The first time a product is reviewed it could be registered for up to 5 years. At the end of each five year period, pesticide manufacturers will be asked to renew their license for another 5 years. Periodically, new information or concerns come to the attention of regulatory officials. Depending on the nature of this new information, it may be appropriate to conduct a special review of some aspect of a pesticide registration i.e. the effect of use on fresh water ecosystems. In other cases, it will be appropriate to do a complete reassessment or reevaluation of a pesticide because the nature of the possibility of a risk of harm to humans and the environment. Presently there are approximately 20 pesticide active ingredients (of the total 500) being reevaluated. The canadian reevaluation process has been organized into eight (8) steps: 1. Prioritization; 2. Conffrmation of Priority; 3. Announcement; 4. Identify and Assess Risk(s) and Value(s); 5. Discussion of Facts and Regulatory Options; 6. Consultation with Stakeholders; 7. Make Decision and Inform Interested Parties; 8. Implementation of Decision.
K McCullogh


EPA’s Current Views on Heavy-Duty Wood Preservative Regulation
2003 - IRG/WP 03-50206
This paper describes the current EPA system for regulating pesticides and wood preservatives. In particular it focuses on the voluntary phase-out of CCA for residential uses after December 30, 2003, which was agreed between the CCA manufacturers and EPA. Even though the EPA reached an agreement with industry to phase out CCA for residential uses, EPA is continuing the most rigorous risk assessment ever done on a wood preservative pesticide. One risk assessment is considering children’s exposure at residential sites and the other focuses on the uses that are not subject to the phase-out agreement, e.g. fence posts and wood in permanent foundations.
F T Sanders


An Update on the Status of Industrial Heavy-Duty Preservatives in Europe
2022 - IRG/WP 22-30762
Creosote has been used for over 150 years for preservation of heavy duty industrial timbers such as railway sleepers, utility poles, and agricultural posts. The regulatory regimes in place today across Europe (eg EU & GB Biocidal Products Regulation (BPR)) require a detailed assessment of the environmental and human health properties of wood preservatives at both the active substance and product levels. Creosote is currently authorised for use in Europe but is now facing further restrictions at the reauthorisation stage which will severely limit its applications. A number of alternatives to the use of creosote treated wood exist in the form of alternative materials such as steel, concrete and polymers / composites. Another alternative is use of wood treated with water-based copper-organic preservatives where service life expectations less than that delivered today by creosote are accepted in some markets. However more recently wood treated products that are designed to deliver a long service life have become available. One such product is Tanasote S40®, which is authorised under the BPR which does not contain creosote and is suitable as a preservative for heavy duty industrial timbers.
S Uphill, H Griffiths, M Giannuzzi, A Hughes


Possible regulatory status of treated wood waste and implications
1998 - IRG/WP 98-50101-07
In relation to the European Community or the French regulations, treated wood waste can get two different regulatory status: <<recycled product or fuel>> or <<waste>>. Then, into the waste status, two categories are possible for these residues: <<domestic waste and assimilated>> or <<hazardous waste>>. These different status and categories are important for the environmental issue of treated wood waste management. But they also can have strong economical implications, linked to the waste management cost on one hand and on the materials image on the other hand. On the basis of the EC regulations, up to now, no treated wood waste is namely quoted as <<hazardous waste>>. However, through the classification criteria defined by different EC directives, creosote or heavy metals treated wood waste could be to considered that way. The technical arguments for such a classification and the practical implications are discussed.
G Deroubaix


Protection of Ochroma pyramidale from fungal decay with N,N-napthaloylhyroxylamine
1998 - IRG/WP 98-30182
Fungal decay of wood in service results in billions of dollars (U.S.) in losses annually. Recent environmental restrictions, both U.S. and international, are limiting and eliminating the use of broad-spectrum, heavy metal biocides for wood preservation. Restrictions result primarily from problems with disposal. New wood preservatives need to be developed and tested which specifically target key elements in the sequence of fungal decay mechanisms. Our laboratory has been experimenting with chemicals which inhibit pectin hydrolysis during incipient brown-rot and white-rot decay in southern pine sapwood (Inter. Biodeter. Biodegrad. 39:103). In the present paper these results are extended to include the tropical hardwood Ochroma pyramidale (balsa). Balsa blocks (24x18x12mm) were exposed to two brown-rot fungi and one white-rot fungus in ASTM soil block tests for 10 weeks. CCA (6.4 km/m3 ) was compared with the calcium binding agent N,N-napthaloylhydroxylamine (NHA; 1.6, 3.2 & 6.4 km/m3 ) in leached and unleached blocks. CCA protected balsa with minimal weight loss (> 7.4%) with no leaching effects. NHA (6.4 km/m3 ) protected balsa (0.3-1.2%) weight loss but leaching raised the weight losses to 25% with the brown-rot fungus Tyromyces palustris. We conclude that NHA can protect balsa against G. trabeum and T. versicolor with comparable efficiency to CCA (leached and unleached) but not T. palustris.
F Green III, T L Highley


Removal of heavy metals from treated wood using biological methods
2005 - IRG/WP 05-50226
Heavy metals were removed from wood treated with copper based preservatives using brown-rot fungus Fomitopsis palustris. The amount of effective elements removed by treatment methods was examined. The relationship between oxalic acid concentration and the amount of heavy metals removed from each treated wood was also investigated. The relationship between fungus weight and removal rate was also included. The removal rates of heavy metals were examined at the different mass of chips and different retention rates and different specimen sizes. Effective element removal rate of preservative-treated wood was compared with different cultivation methods. Based on the results of lab-scale experiment, an air lifting bioreactor was employed for its large-scale operation. The efficiency of bioreactor was evaluated.
Dong-won Son, Dong-heub Lee


Effect of EDTA on removal of CCA from treated wood
2002 - IRG/WP 02-50182
Since substantial amounts of chromated copper arsenate (CCA) remain in the wood for many years, the disposal of CCA-treated wood causes escalating environmental concerns. Additionally, wood waste is generated when treated wood is put into service, for which environmentally benign disposal technologies need to be developed. Novel approaches to remove copper, chromium, and arsenic from CCA-treated waste wood are needed to overcome such environmental concerns. Acid extraction, one of the most extensively used methods, has been studied by several researchers for removal of copper, chromium, and arsenic from CCA-treated wood. In this study, EDTA (ethylenediaminetetraacetic acid) extraction of copper, chromium, and arsenic from CCA- treated wood was evaluated using batch-leaching experiments. EDTA is one of the most common chelator used to bind the metal ions in extremely stable complexes in heavy metal contaminated soils and thus to remediate such substrates. EDTA forms water soluble complexes with many metal ions and it is used to release for the various metals. In the study, chips and sawdust containing CCA were processed by EDTA extraction to remove the metal elements present in the form of oxides. CCA-treated wood samples were extracted with four different concentrations of EDTA (0.0, 0.01, 0.1, and 1.0%) for 4 and 24 hours at room temperature. Exposing CCA-treated chips and sawdust to EDTA extraction enhanced removal of CCA components compared to extraction by deionized water. Grinding CCA-treated wood chips into 40-mesh sawdust provided greater access to and release of CCA components. Extraction with 1% EDTA solution for 24 h released 60% copper, 13% chromium, and 25% arsenic from treated chips. EDTA extraction of treated sawdust samples resulted in 93% copper, 36% chromium, and 38% arsenic release. The pH of EDTA solutions ranged from 2.2 to 3.2, providing acid conditions, which facilitate release of copper element. The results suggest that EDTA extraction removes significant quantities of copper from CCA-treated wood. Thus, EDTA could be important in the remediation of wood waste treated with the newest formulations of organometallic copper compounds and other water-borne wood preservatives containing copper.
S N Kartal


HCB - a new preservative combination for wood pole maintenance
1996 - IRG/WP 96-30122
New combination of heavy creosoted boron (HCB) applied on hardwood and softwood logs at different moisture content revealed successful diffusion of boron in all sapwoods within 7 days and in all sapwoods plus hardwoods within 15 days. The new cost effective paste sterilizes wood through diffusion and suitable for pole maintenance at groundline and above groundline e.g. cut ends, drilled holes, woodpecker&apos;s holes etc.
A K Lahiry


Bioassays for rapid assessment of heavy metal toxicity in seawater
1998 - IRG/WP 98-50112
In evaluating the effect of CCA leachate on the establishment of fouling communities on wood exposed in the sea, three organisms were assessed as biological indicators of heavy metal toxicity. These were two macroalgae, Fucus serratus and Undaria pinnatifida. and the motile protist thraustochytrid, Schizochytrium aggregatum. The choice of these organisms for the tests carried out was based on the need for rapid methodology and relative simplicity in their isolation and cultivation. The two test algae were collected locally on the south coast of England, cleaned of surface contamination and prepared for release of their respective reproductive spore types. Toxic effects of a range of concentrations of CCA leachate were then measured in terms of spore/zygote germination using simple microscopic observations after 3-4 days incubation. The thraustochytrid was obtained from stock cultures held at the University of Portsmouth. The zoosporic stage in the life cycle of this organism was used to indicate the toxic effects of copper ions in seawater-based medium by measuring loss in motility over a 20 minute period. Data were collected using motion analysis equipment. Subsequent recovery of zoospores after 1 hour exposure to different copper levels was determined. Non-motile stages of the life cycle of thraustochytrid isolates were also used to determine copper toxicity. Tolerance of these organisms to heavy metals in CCA leachates will be discussed.
C J Brown, R L Fletcher, R A Eaton


Equilibrium distribution of toxic elements in the burning of impregnated wood
2001 - IRG/WP 01-50172
The current work focuses on predicting the behavior of arsenic, chromium, and copper in the burning of impregnated wood. A theoretical method is used to study the chemistry of the system, with special interest directed towards the vaporization tendency of the potentially toxic elements. The core of the study is the global equilibrium analysis that simultaneously takes into consideration all chemical reactions. The results of the present study indicate that chromium and copper are unlikely to volatilize at combustion temperatures. Arsenic appears to be more volatile. Nevertheless, the prediction showed that it may be captured by calcium of the wood ash, and small amounts are likely to dissolve in the slag-phase of the ash. It may also form non-volatile compounds with magnesium, copper, and chromium and other elements of the impregnated wood, which efficiently hinders its emissions as gaseous species.
K Sandelin, R Backman


Environmental fate of copper-based wood preservatives in different soil substrates - Part 2: Study of the metal sorption and migration potential under simulated rainfall
1998 - IRG/WP 98-50101-21 b
In order to examine the potential environmental impact of spillages of the saltborne wood preservative CCA in treatment plants, four large scale experiments are set-up so as to follow the water transport and ion mobility in various field soils. A plastic container is filled with a sand, silt, clay and potting soil, made up at their respective bulk density and wetted to a given moisture content. Using a rain simulator on top, a homogeneous spillage of a ready-to-use CCA solution is applied, followed by a rainfall simulation after 3 days and a 3 weeks redistribution period. Soil augers that are taken prior to each new perturbance reveal the distribution and migration pattern of the heavy metals. Copper and arsenic are strongly adsorbed in the upper soil layers, depending on the soil characteristics. Chromium, however, is percolated easily through the soil column and is readily extractable from the soil using pure water.
G M F Van Eetvelde, R Hartmann, J M Mwangi, H S Öztürk, M Stevens


Emissions from the combustion of wood treated with organic and inorganic preservatives
1994 - IRG/WP 94-50019
Wood waste and industrial wood residues often contain various preservatives. The waste management for these residuals can be recycling, deposition or combustion. Among the three possibilities, combustion seems to be the most efficient way of usage. To obtain more information about the emission properties of treated wood, different materials were incinerated in different furnaces after mixing with non-treated wood in a ratio of 1:4. For sake of comparison, combustion was also performed using non-impregnated wood only. The combustion process of residues containing organic or inorganic preservatives is influenced by the elementary composition of the preservative and the thermal and oxidative reaction paths in the flame. Organic preservatives mostly can be thermally destructed by usual combustion conditions. Elevated conditions are necessary for preservatives based on creosotes (tar oil). Among inorganic preservatives, volatile ingredients like fluorine have a considerable environmental impact. Other elements like copper, chromium and boron remain in ashes and cinders reducing the emission problem towards an effective dust removal. It was also found that the concentrations of the gaseous emission components CO, NOx and CmHn are not increased in comparison to the values being found for non-treated wood. However, the concentrations of polychlorinated dibenzo-dioxins and -furans in the exhaust gas could only be kept low under optimized combustion conditions.
T Salthammer, H Klipp, R-D Peek, R Marutzky


Production, function and neutralization of oxalic acid produced by the dry rot fungus and other brown rot fungi
1987 - IRG/WP 1330
The formation of oxalic acid by the wood-destroying fungi causing brown rot, is found to be the key which by hydrolysing the hemicellulose brings the cellulose in the tracheid wall in contact with the cellulase enzymes and yeld watersoluble sugars leaving only a lignin skeleton. To control the pH in the substrate the excess oxalic acid is precipitated to water insoluble calcium oxalate by the dry rot fungus in contact with a calcium source. As source glass can be used, however, mortar, concrete or clay soil is better. Heavy metals that form complex compounds with oxalic acid can substitute calcium certain to a degree. The wet rot fungus Coniophora putenea is not dependent on calcium like the dry rot fungus. By producing acetic as well as oxalic acid it might form a buffer solution which controls the pH in the substrate.
J Bech-Andersen


Thermal decomposition behavior of CCA-treated wood for safe disposal and the safe recovery of heavy metals through pyrolysis
2006 - IRG/WP 06-50238
If we could estimate the chemical changes in heavy metals by temperature in chromated copper arsenate (CCA)-treated wood during pyrolysis, it is expected that we could solve the environmental problems of heavy metals, which may occur during pyrolysis, and therefore, the thermal decomposition behavior of effective elements of CCA-treated wood was examined to find a safe disposal method. First, CCA-treated wood was combusted at a temperature that prevents volatilization of arsenic compounds, and the arsenic compounds were extracted from carbonized wood. Then, it was considered how to recover heavy metals from chromium compounds and copper compounds. The Thermo Gravimetric Analysis (TGA) result of CCA-treated wood showed that arsenic (III) oxide was volatilized into the atmosphere at 300? and arsenic (V) oxide was volatilized at 800?. When heavy metals were recovered from the carbonized-treated wood after thermal decomposition of CCA-treated wood at 300?, which could suppress the volatilization of arsenic compounds, it was relatively easy to recover copper and arsenic while it was difficult to recover chromium from the carbonized-treated wood.
Dong Won Son, Dong-heub Lee, Sun-hae Cheon, Myung Jae Lee


Effect of Heavy Metals on the Expression of Manganese Dependent Peroxidases of Phanerochaete chrysosporium
2010 - IRG/WP 10-10722
This work is part of an ongoing investigation that studies the application of a solution rich in Zn and Mn, obtained from a recycling process, as a preservative for wood. The effects of Zn2+ and Mn2+ on the enzyme-expression level of manganese-dependent peroxidase (MnP) from Phanerochaete chrysosporium was studied by real-time PCR. The glyceraldehyde 3-phosphate dehydrogenase gene (gpd) was used as reference for the relative quantification of the expression of the three isoenzymes. The expression kinetics was studied for different media and culture conditions. The conditions and culture time leading to maximum gene expression and enzyme activity were determined for each isoenzyme. The effects of medium composition (replete, ligninolytic: carbon-limited, nitrogen-limited), temperature (28ºC and 37ºC), and shaking (static or agitated at 125 rpm) were studied. Incubation in a static carbon-limited medium at 37ºC showed the highest expression of the mnp genes. In these conditions, the concentration of Zn2+ and/or Mn2+ that stimulate or inhibit the expression of mnps was determined. The selection of suitable culture conditions and the sensitivity of real-time PCR enabled a differentiation in the expression pattern of the three studied MnP isoenzymes in the Zn2+ and/or Mn2+-containing media. Zn2+ concentrations lower than 0.5 mM led to variable expression levels for the different isoenzymes, but were found to have a clear inducing effect when Zn2+ was used in combination with 100 µM Mn2+. Results of the above analysis were compared with enzymatic activity data obtained spectrophotometrically.
C Ibáñez, M Rabinovich, M Barraco, G Gecchetto, M Cerdeiras


Laboratory study of toxicity or tolerance of CCA preservative and heavy metal constituents copper, chromium and arsenic to Malaysian tropical fungi
2011 - IRG/WP 11-30579
CCA preservative and its constituent heavy metal tolerance and toxicity to 3 Malaysian isolates Phialophora fastigiata (soft rot fungus), Paecilomyces variotii (mould fungus) and an unidentified white rot Basidiomycete, was investigated by the modified ‘Strange-Smith’ agar-well-plate technique with 1.6% CCA concentration and the malt-agar-plate bioassay technique with a range of CCA and constituent metal salt concentrations of 0.0024 – 5%m/m. Daily linear hyphal extension was measured between 6 and 22 days depending on relative fungal growth rates. The slow growing Phialophora fastigiata sustained mean daily hyphal growth (mm) at relatively higher concentrations of CCA preservative (toxic limits: 0.24 – 0.48%m/m) and their heavy metal constituents (copper-salt: 5.0 – 10.0%m/m; chromium-salt: 0.076 – 0.24%m/m) than the faster growing mould isolate Paecilomyces variotii (CCA: 0.019 – 0.076%m/m; chromium-salt: 0.076 – 0.24%m/m) and the white rot Basidiomycete of intermediate growth rate (CCA: 0.076 – 0.24%m/m; copper-salt: 0.076 – 0.24%m/m; chromium-salt: 0.0095 – 0.019%m/m) except for arsenic-salt (Phialophora fastigiata: 0.076 – 0.24%m/m; Paecilomyces variotii: 0.48 – 0.95%m/m; Basidiomycete: 0.24 – 0.48%m/m). The results showing varying efficacies (toxicity versus tolerance) in vitro of CCA and their metal constituents between these fungi can have implications to ground-contact wood protection capabilities of CCA.
A H H Wong, T Mark Venås, N Morsing, C C L Tan, P K F Chong