Your search resulted in 319 documents. Displaying 25 entries per page.
A new accelerated field test for termites
1983 - IRG/WP 1178
A new accelerated field test method for termites is described. Two series of tests were conducted with this accelerated method and the results were very encouraging.
W E Conradie, A Jansen
Do CCA treated support stakes cause increased arsenic level in crops?
2003 - IRG/WP 03-50204
Trial of using CCA-C treated eucalypts stakes for supporting banana plants in Guangdong Province, China, began in 1998 and later it was expanded as a demonstration program of a joint International Tropical Timber Organization–Chinese Government timber preservation project in 2000. The greatest concern was whether the crop would be contaminated by the preservatives, arsenic in particular. Data from four years tracking analysis of bananas collected from the demonstration plots indicated that the arsenic levels were not significantly higher than the levels found in plants supported by untreated stakes. The arsenic content in bananas supported by preservative treated stakes was well below the level specified in food standards of China. Similar results were obtained from a trial of tomatoes and garden peas supported with treated eucalypts and round bamboo posts in pottery pots.
Li Zhaobang, Su Haitao, Liang Linqing
The content and mobility of copper, chromium and arsenic in the soil of a wood preserving plant using CCA
1998 - IRG/WP 98-50122
Analyses were carried out on soil and water samples obtained from a wood preserving plant using CCA-type preservatives. The plant has been in operation since 1969. The soil samples were obtained on 8 points from 4 different depths. The estimation of the type of soil was followed by investigations of copper, chromium and arsenic contents, and the mobility of these elements. The soil samples were also analyzed for their organic material and carbon contents. Water sample, obtained from a well within the area of the plant, and wood samples, from trees grown in the area, were also analyzed using Atomic Absorption Spectroscopy. In the desorption tests using acidic medium soils yielded among 1 and 513 mg/kg As, between 6 and 1945 mg/kg Cu, between 21 and 2400 mg/kg Cr; using distilled water they yielded between 1 and 23 mg/kg Cr; Cu concentration remained below the detection limit of the method applied.
N Erdin, S N Kartal, A Dilek Dogu, M O Engür
The growth and metal content of plants grown in soil contaminated by a copper/chrome/arsenic wood preservative
1977 - IRG/WP 3110
Salts of copper, chromium and arsenic are used together in water soluble formulations for the preservation of wood against insect and fungal attack. Copper/chrome/arsenic (CCA) preservatives are of proven efficacy and, used correctly, ensure a useful service life for timber for 30 years or more with little, if any, attendant threat to the environment from the treated wood itself. The preservative treatment site can, however, provide a point of entry for the preservative into the general environment by way of spills and leaks of the treating fluid and run off from treated wood, with resultant contamination of the surrounding soil. The possible effects of the CCA salts on plant growth and metals uptake are the subject of this paper. In a series of greenhouse pot experiments the effects of varying concentrations of CCA in soil on the germination, growth and cropping of beans, carrots and tomatoes was studied. Crops produced by the plants were analysed for their copper, chromium and arsenic contents. Additionally, grasses were grown to assess possible land reclamation difficulties. It was found that soil having a combined copper, chromium and arsenic concentration of approximately 7000 ppm completely inhibited the growth of all the plants tested, while certain concentrations below this inhibited or retarded growth to some degree. Carrots grown in soil containing approximately 1000 ppm Cu, Cr, As (200 ppm As) produced crops containing nearly twice the current recommended limit for arsenic in food. Relating the levels of CCA used in the experimentally dosed soil with the amounts found in soil samples taken from preservative treatment sites, it is apparent that many contaminated areas would not support plant life. Less heavily contaminated soil will support growth and may give rise to crops with arsenic levels higher than those deemed to be safe.
C Grant, A J Dobbs
Moisture content levels and decay of hemlock
1986 - IRG/WP 1287
As a model of decay conditions of wooden members in wooden houses, a decay test was set up in which samples of western hemlock (Tsuga heterophylla) under 4 moisture levels were examined. Each week the samples were weighed and if the weights indicated that their moisture contents were lower than the expected levels, distilled water was added. Every 8 weeks 3 samples from each condition were oven dried at 60°C for 48 hours, up to 48 weeks. After 48 weeks, 3 samples from each condition were oven dried every 16 weeks. The results obtained were as follows: After examining the samples for 96 weeks at 27°C, the mean weight loss of the hemlock samples kept at about 50-100% moisture content level was larger than those of the other levels. If the samples were dried every 8 weeks, the amount of decay in them was not significant. Decay was also not significant in the samples kept at approximately 20-30% moisture content level.
A discussion on causes, effects and remedies of arsenic pollution of groundwater in Bangladesh
1998 - IRG/WP 98-50102
This paper includes possible causes, effects and remedies of arsenic pollution of groundwater in Bangladesh, extracted mostly from the international conference held in Dhaka in 1998. Next possible key steps have been suggested based on scientific principles and experience. The release of arsenic from underground sediment would be due to excessive mechanical forces, geochemical and geobiological reactions. Arsenic free water will cure acute patients and will save future generations. Use of suitable organic chemicals, organic matters, biological control system would be widely acceptable for supplying arsenic free water. Other natural sources of water can be used easily and safely without mechanical and chemical processes. The problems of chronic patients would be solved genetically, enzymatically and nutritionally.
A K Lahiry
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
New technique to analyze impregnation processes
1988 - IRG/WP 2304
Equipment has been developed to measure liquid flow in wood during impregnation processes. Basic principles of flow measurements using directly heated negative temperature coefficient thermistors, and some characteristics of the hardware developed are presented in this paper.
J P Hösli
Soil virulence tests using Scots pine sapwood
1973 - IRG/WP 222
Following the tests reported in Document No: IRG/WP/210, in which soils from different laboratories were investigated for virulence, supplementary tests have been carried out using Scots pine sapwood and an extended incubation period.
J K Carey, J G Savory
Co-operative research project on L-joint testing. Sampling after 8 months exposure
1983 - IRG/WP 2208
It was anticipated in Document No IRG/WP/2192 that exposure of L-joints by the European co-operators would take place on 1 April 1983. Where L-joints were exposed at this time, sampling after 8 months exposure is due on 1 December 1983. The present document draws attention to relevant previous documents which describe the sampling methods to be adopted. It also provides Tables for recording the results.
J K Carey, A F Bravery
Comparison of the agar-block and soil-block methods used for evaluation of fungitoxic value of QAC and CCA wood preservatives
1994 - IRG/WP 94-20039
The modyfied agar-block and soil-block methods were used for comparing the fungitoxic value of QAC and CCA type preservatives against Coniophora puteana and Coniophora olivacea The mass loss and moisture contents of wood were analysed.
J Wazny, L J Cookson
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
Insect resistance of preservative treated tropical plywood against Lyctus
1990 - IRG/WP 1453
Seven plywood types composed of tropical wood species, vulnerable to Lyctus, were treated with various commercial water-borne and oil-borne preservatives. A wide range of preservative retentions was obtained by treating boards with dip treatment, steeping, double-vacuum and vacuum-pressure impregnations. Selected samples were subsequently tested for their insect resistance against Lyctus africanus during 6 to 8 months according to European Standard EN 20. All control samples were attacked, except one Obeche plywood exhibiting only 50% attack. Water-borne preservative solutions containing arsenic, boron or fluoride could not prevent attack at common retention levels for interior use e.g. lower than 5 kg/m³. Quaternary ammonium compounds showed no insecticidal efficiency, up to 3 kg/m³. TCMTB at 1.5-1.7 kg/m³ proved to be able to reduce slightly the susceptibility for insect attack. Organic insecticides gave the best results, with nearly no attack for plywood treated with lindane or cypermethrin. In spite of a preservative uptake of 25 to 30 kg/m³, endosulfan only could reduce attack by 50%. Protection by permethrin at 0.1% a.i. required a retention of 28 kg/m³. Besides the fact that variability in wood species and composition of the plywood are leading to different retention levels, variation in penetration and distribution of a.i., and as a consequence to a different insect resistance of the impregnated boards, some poor results were directly related to inadequate insecticidal activity and/or concentration of a.i. in some commercial formulations for Lyctus control.
J Van Acker, M Stevens, M Pallaske
A medium for mass culturing of a bamboo boring beetle Dinoderus minutus Fabricius
1983 - IRG/WP 1182
The bamboo is a traditional product of Japan. But its susceptibility to insects is one of the most important problems. The author has found that for the determination of the effectiveness of insecticides it is very easy to obtain sufficiently numerous adults of Dinoderus minutus by using Buckwheat Cake. The Buckwheat Cake is prepared with buckwheat flour and thin paper. The author has previously found that Buckwheat Cake is suitable for the culturing of Lyctus brunneus and these results were presented in 1981. In culturing Dinoderus minutus, Buckwheat Cake has been found to be also easier and fasting in bringing forth the adults than natural bamboo.
Influence of moisture content of rubber wood on the growth of Botryodiplodia theobromae
1993 - IRG/WP 93-10029
Botryodiplodia theobromae is the main fungus causing sapstain on rubber wood (Hevea brasiliensis). The entry and establishment of the stain fungus is nighly influenced by the moisture content of the wood. To determine the optimum moisture content of wood required for maximum growth of Botryodiplodia theobromae wood blocks at different moisture contents were inoculated with the test fungus and incubated for a period of two weeks. The study showed if the moisture content of the wood was reduced to less than 24%, the wood can be protected from fungal sapstain.
E J M Florence, R Gnanaharan, J K Sharma
Leaching of copper, chromium and arsenic from CCA-treated Scots pine exposed in sea water
2000 - IRG/WP 00-50149
A laboratory leaching trial combining a static and a flowing seawater system was carried out to measure the leaching rates of copper, chromium and arsenic from the surface of Scots pine panels vacuum-pressure treated to 3, 6, 12, 24, and 48 kgm-3 CCA. Untreated and treated panels were exposed in flowing seawater for up to 8 weeks followed by 2 weeks submersion in static seawater which was taken for analysis. The study revealed a leaching hierarchy of Cu>Cr>As which supports the findings of other investigators. Over the 8 week leaching trial there was a time-related decrease in the rate of copper and chromium loss. Over the first week of leaching in flowing seawater, the rates of loss of copper and chromium decreased to between one-half and one-seventh, followed by lower rates of leaching over the remaining period of the investigation. In contrast, the rate of loss of arsenic from the wood appeared to increase slightly over the same period. The data are compared with minimal leaching rates of toxins from the surface of anti-fouling paints and are discussed in terms of the fouling communities which are established on Scots pine panels treated to similar target retentions.
C J Brown, R A Eaton
Collaborative soft rot tests: Programme and test method
1973 - IRG/WP 229
J G Savory, J K Carey
La rôle de l'expert dans l'évaluation toxicologique
1990 - IRG/WP 3589
Collaborative soft rot tests: Interim report on PRL tests of Cu/Cr/As preservative using method of Document No: IRG/WP/208
1972 - IRG/WP 211
Preservative: Tanalith CT.106 - Results obtained with beech are given in the table and indicate a toxic limit of 16.7-19.2 kg/m³ - The initial soil moisture content was adjusted to 27.8% (the water holding capacity). Noticeable drying out has occurred in some of the test bottles.
J G Savory
Soft rot and bacterial decay in preservative treated eucalypt power transmission poles
1982 - IRG/WP 1155
Bacterial type decay was observed in CCA and PCP treated eucalypt power transmission poles. Detailed observations made with the SEM revealed bacterial colonisation and decay, especially in fibres. Plug samples taken from poles throughout Queensland were examined for preservative retention and presence of soft-rot decay. The severity of decay was different according to location, retention and species.
L E Leightley
Rates of emission from CCA-treated wood in the marine environment: measurement, modelling and requirements for further research
2001 - IRG/WP 01-50166-12
Accurate estimates of rates of emission of leachate from preservative treated wood are crucial for realistic predictions of the environmental impact of its use in maritime construction. Estimates are available for some commonly used preservatives, but these vary widely. Though variable, these measurements suggest that emission generally decreases exponentially with time. Part of the variation is due to differences in methodology employed. Physical and chemical characteristics of the seawater used (e.g. temperature, salinity, pH and oxygen content) affect emission rate. So too do the specifics of the treatment process especially the preservative formulation used, and pre- and post-treatment handling of the wood. The nature of the treated wood samples is also important, with misleadingly high estimates being obtained from samples with unrepresentatively high proportions of cross-cut surfaces. A suggested strategy for developing an informative and standardised methodology is discussed. To form useful models of impacts of leaching, emission rates need to be considered in conjunction with site-specific information regarding a) water exchange rates between the area where leaching occurs and the sea, and b) the extent of partitioning of leachate between the water column, biota and sediment. The risk of environmental impact may be reduced by modification to treatment procedures and by careful planning of installation.
S M Cragg, C J Brown, R A Albuquerque, R A Eaton
Improved PEC preservatives with added biocides
1985 - IRG/WP 3322
Biocidal chemicals have been incorporated into formulations within the broad framework of pigment emulsified creosote (PEC) to provide novel potential multi-purpose preservatives. Preparations of PEC plus TCMTB, Boracol 40, copper ethanolamine nonanoate, Quatramine 80, arsenic trioxide, Troysan Polyphase, and CCA have been formulated and assessed for preserving ability in soil-jar and Accelerated Field Simulator tests. In addition, a cationic oil-in-water emulsion preservative combination of PEC and CCA (PECCA), and an anionic formulation of TCMTB with PEC (PECBUS) have been manufactured in 400 L quantities to treat hardwood pole stubs and pine posts. The results indicate the potential of these improved second generation PEC-based preservatives to provide low-creosote containing treatments able to protect commodities against biodeterioration as well as provide dry, clean surfaces.
H Greaves, C-W Chin, J B Watkins
Observations on the failure of anti-sapstain treated timber under non-drying conditions
1990 - IRG/WP 1437
A range of bacteria and yeasts were isolated from antisapstain treated timber and fresh sawdust. Solution samples containing 100 ppm of TCMTB in a nutrient medium were inoculated with these organisms and incubated at 25°C for 5 days. The levels of TCMTB remaining in solution were determined by HPLC analysis after this time. Results indicated high losses of active ingredient for a range of organisms. These results suggest that active biodetoxification of organic biocides could occur in a short period of time during storage of antisapstain treated timber under favourable conditions. The implications of these results are discussed.
G R Williams
Nitrogen content of soils at field sites
1981 - IRG/WP 1133
Nine participants in the Collaborative Field Experiment submitted samples for nitrogen analysis to this laboratory as requested by Leightley (IRG/WP/3162). These arrived in a variety of conditions e.g. wet, dried, sterilised and unsterilised and sometimes spent a considerable time in transit. Soils varied in cellular fraction organic matter content, some were obviously sieved prior to postage while others contained significant quantities of large vegetative detritus. Samples were also taken at different times of the year and seasonal and climatic factors may have influenced the values subsequently obtained by analysis.
B King, G Mowe
Microbial biofouling of 10-40% naphthalene in creosote treated and untreated wooden pilings in the marine environment
1978 - IRG/WP 442
R R Colwell, P L Fish, D A Webb, A J Emery