Australian Pesticides and Veterinary Medicines Authority (APVMA) Part two: Environmental Assessment 1/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 1. INTRODUCTION.......................................................................................................9 2. CHEMICAL IDENTITY............................................................................................10 2.1. COPPER CHROME ARSENATE.................................................................................10 2.2. ARSENIC TRIOXIDE.....................................................................................................11 3. PHYSICAL AND CHEMICAL PROPERTIES .........................................................11 3.1. COPPER CHROME ARSENATE COMPONENTS ...................................................11 3.1.1. Copper........................................................................................................................11 3.1.2. Chromium..................................................................................................................12 3.1.3. Arsenic.......................................................................................................................13 3.2. ARSENIC TRIOXIDE.....................................................................................................14 4. FORMULATIONS...................................................................................................14 4.1. COPPER CHROME ARSENATE FORMULATIONS...............................................14 4.1.1. CCA formulation types..............................................................................................14 4.1.2. Formulations of CCA currently registered in Australia.............................................15 4.2. Arsenic trioxide termite treatments................................................................................16 5. ENVIRONMENTAL EXPOSURE............................................................................17 5.1. Application/treatment methods......................................................................................17 5.1.1. Copper Chrome Arsenate...........................................................................................17 5.1.1.1. Treatment process and fixation of CCA.............................................................17 5.1.1.1.1. Overall comments...........................................................................................17 5.1.1.1.2. Changes in composition of CCA components during fixation.......................18 5.1.1.2. Australian Standards pertaining to application and use.....................................19 5.1.1.2.1. Recently developed standards.........................................................................19 5.1.1.2.2. Relevance to environmental protection...........................................................20 5.1.1.2.3. Past use and current adherence to these standards..........................................22 5.1.1.3. Application rates................................................................................................23 5.1.2. Arsenic trioxide..........................................................................................................26 5.2. Environmental release.....................................................................................................27 5.2.1. Copper Chrome Arsenate...........................................................................................27 5.2.2. Arsenic trioxide..........................................................................................................28 6. ENVIRONMENTAL FATE.......................................................................................28 6.1. Fate of copper, chromium and arsenic in the environment.........................................28 6.1.1. GENERAL FATE AND BEHAVIOUR....................................................................28 2/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 6.1.1.1. Arsenic...............................................................................................................28 6.1.1.2. Copper................................................................................................................29 6.1.1.3. Chromium..........................................................................................................30 6.1.2. Volatility....................................................................................................................30 6.1.3. FATE AND BEHAVIOUR OF ELEMENTS ADDED TO SOIL AS CCA OR CCA LEACHATE...............................................................................................................................31 6.1.3.1. General overviews..............................................................................................31 6.1.3.2. Artificial contamination of synthesised soils with CCA....................................31 6.1.3.3. Mobility of CCA components from direct spillage onto soil in Belgium..........32 6.1.3.4. CrVI leaching from large lysimeters in New Zealand following CCA application 33 6.1.3.5. Composition of CCA leachate and effects of passage through soil in New Zealand 34 6.1.3.6. Effect of soil physical and chemical characteristics on adsorption....................35 6.1.4. Summary and conclusions regarding fate and behaviour of copper, chromium and arsenic in CCA and CCA leachate once it reaches soil and water.............................................36 6.2. Reports of environmental contamination from CCA...................................................37 6.2.1. Studies pertaining to treatment facilities....................................................................37 6.2.1.1. Mobility of arsenic, copper and chromium in CCA-contaminated soil beneath Swedish preservation plants...................................................................................................37 6.2.1.2. Contamination at another Swedish site..............................................................38 6.2.1.3. Mobility of arsenic, copper and chromium in CCA-contaminated soil beneath a Turkish preservation plant......................................................................................................39 6.2.1.4. Contamination at sites in the United Kingdom..................................................40 6.2.1.5. Contamination of soil beneath a Norwegian treatment facility..........................40 6.2.1.6. Release to the aquatic environment from the above facility..............................40 6.2.1.7. Fate and bioavailability of CCA components in sediments near an old Finnish sawmill site 41 6.2.1.8. Release to the aquatic environment from a preservative facility in Georgia, USA 42 6.2.2. Off site contamination during service........................................................................42 6.2.3. Summary and conclusions regarding reports of environmental contamination with CCA 43 6.3. Release of CCA components from CCA-treated timber..............................................45 6.3.1. Fixation and leaching of CCA components...............................................................45 6.3.1.1. Definitions of fixation and leachability..............................................................45 6.3.1.2. Importance of achieving adequate fixation........................................................45 6.3.1.3. Methods of assessing fixation and leachability..................................................45 6.3.1.3.1. Evaluating fixation using expressate from moist wood..................................45 6.3.1.3.2. Comparison of other methods to assess fixation with expressate evaluation.46 6.3.1.3.3. What level of fixation is “adequate”?.............................................................46 6.3.1.3.4. Assessment of fixation using shower tests......................................................47 6.3.1.3.5. Influence of surface area effects in fixation and leaching rate tests................47 6.3.1.3.6. Need to standardise leaching rate test methods and practical interpretation of results 47 6.3.1.3.7. Losses in laboratory, 9 month soil bed and 12 months above ground depletion tests at different CCA retentions in the USA.....................................................................47 3/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 6.3.1.3.8. Losses in an outdoor above ground exposure test with pegs compared to a laboratory test.....................................................................................................................48 6.3.1.3.9. OECD test recommendations for environmental assessment purposes..........48 6.3.1.3.10. Towards estimation of potential leaching rate from wood in service using test data 49 6.3.1.3.11. Comparison of standard leaching protocols and sample particle size effects in regard to waste disposal.................................................................................................50 6.3.1.4. Summary and conclusions regarding fixation and leaching assessment............51 6.3.2. Factors influencing fixation and subsequent leachability of CCA components during treatment, fixation and drying of wood (ie prior to use)............................................................52 6.3.2.1. Managing CCA treatment for optimum economy, efficiency and performance52 6.3.2.2. Application process............................................................................................52 6.3.2.3. Composition of the CCA solution......................................................................52 6.3.2.4. pH and concentration of the CCA solution used during treatment....................53 6.3.2.5. Initial retention...................................................................................................53 6.3.2.6. Temperature during treatment and fixation........................................................53 6.3.2.7. Relative humidity, air circulation and sunlight..................................................54 6.3.2.8. Wood species, wood quality and seasoning.......................................................54 6.3.2.9. Heartwood vs sapwood......................................................................................55 6.3.2.10. Summary and conclusions regarding factors influencing fixation and leaching during treatment.....................................................................................................................55 6.3.3. Redistribution and disproportionation of CCA components......................................56 6.3.3.1. “Disproportionation” of CCA components........................................................56 6.3.3.2. Migration of CCA components within the wood...............................................56 6.3.3.3. Redistribution of CCA components into untreated wood..................................57 6.3.3.4. Summary and conclusions regarding disproportionation, migration and redistribution of CCA components........................................................................................57 6.3.4. Factors affecting leaching during use.........................................................................57 6.3.4.1. pH 3.5-5.5 and presence of organic acids..........................................................57 6.3.4.2. pH 2-6.4 and different CCA formulations.........................................................58 6.3.4.3. Acid rain.............................................................................................................59 6.3.4.4. Water temperature..............................................................................................60 6.3.4.5. pH 3.5-8.5 in soil-water extracts........................................................................60 6.3.4.6. Humic acids........................................................................................................61 6.3.4.7. Cation exchange capacity (CEC).......................................................................61 6.3.4.8. Inorganic salt solutions.......................................................................................61 6.3.4.9. Effect of US soil physical and chemical characteristics on leaching.................62 6.3.4.10. Summary and conclusions regarding factors affecting leaching from timber during use 63 6.3.5. Effects of surface coatings, water repellents and cleaning methods..........................63 6.3.5.1. Effect of coating materials on leaching of CCA in Thailand.............................63 6.3.5.2. Above ground leaching from structural timber – species, CCA loading and water repellent coating in Canada..........................................................................................64 6.3.5.3. Above ground leaching from structural timber – water repellents applied during or after CCA treatment in Canada..........................................................................................65 6.3.5.4. Above ground leaching from structural timber – water repellents applied during CCA treatment in the USA....................................................................................................66 6.3.5.5. Leaching from small deck units in Canada – effects of deck washes and brighteners 67 4/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 6.3.5.6. Summary and conclusions regarding the effects of water repellent treatments, coatings and cleaning methods on leaching...........................................................................68 6.4. Field and semi-field investigations..................................................................................69 6.4.1. Leaching from stakes, poles and posts in trials and actual use situations..................69 6.4.1.1. Leaching from test stakes in ground contact and above ground in Norway......69 6.4.1.2. Loss of CCA components from treated stakes into soil in the UK....................70 6.4.1.3. Leaching of CCA from exposed wooden stakes in Mississippi.........................70 6.4.1.4. Residual CCA levels in treated poles removed from service in Canada............71 6.4.1.5. Evaluation of wood, soil and run-off water from poles in service in Canada....72 6.4.1.6. Loss from poles, piling, posts and stakes treated with CCA in the USA...........74 6.4.1.7. CCA-C depletion of utility poles in Georgia.....................................................75 6.4.1.8. Leaching of CCA-B from Finnish poles in service and levels in soil................75 6.4.1.9. CCA depletion from treated poles in Canada and levels in soil water...............76 6.4.1.10. Long term mobility of CCA from posts in Florida............................................76 6.4.1.11. CCA-component levels in soils around poles in Florida....................................79 6.4.1.12. Summary and conclusions regarding studies of CCA-treated poles, posts and stakes 80 6.4.2. Leaching from structures such as decks, fences, playground equipment and walkways83 6.4.2.1. Leaching from simulated deck units in Queensland and interactions of leachate with soils 83 6.4.2.2. CCA-component levels in soils below decks in Connecticut............................85 6.4.2.3. CCA-component levels in soils below structures in Florida – initial study.......85 6.4.2.4. CCA-component levels in soils below decks and fences in Florida..................88 6.4.2.4.1. Fences..............................................................................................................88 6.4.2.4.2. Decks...............................................................................................................88 6.4.2.5. Decks constructed over a leachate collection system in Florida........................88 6.4.2.6. CCA-treated playground equipment in Virginia and California........................89 6.4.2.7. Soil levels below CCA-treated playground equipment in Sweden....................92 6.4.2.8. Levels of CCA components in the basement sump of a treated structure..........92 6.4.2.9. Tasmanian walkway study.................................................................................93 6.4.2.10. Summary and conclusions regarding levels of CCA components in the vicinity of structures such as decks, fences, playground equipment and walkways...........................93 6.5. Surface residues................................................................................................................95 6.5.1. Introductory comments..............................................................................................95 6.5.2. Original Australian study...........................................................................................95 6.5.3. Measurements using actual hand wiping...................................................................96 6.5.4. Surface arsenic levels on CCA-C treated lumber by a brushing method...................97 6.5.5. Surface arsenic levels on CCA-C treated lumber by a simple tissue wipe test method 97 6.5.6. A systematic polyester wipe method to test surface copper, chromium and arsenic levels on treated timber..............................................................................................................97 6.5.7. Surface arsenic levels on CCA-C treated lumber by a systematic wipe test method.98 6.5.8. Australian playground equipment tests – public submission.....................................99 6.5.9. Summary and conclusions regarding levels of CCA components on the surface of treated wood...............................................................................................................................99 6.6. Plant uptake and leaching in garden and agricultural situations..............................100 5/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 6.6.1. General comments on plant uptake from arsenic in soil..........................................100 6.6.2. Leaching from wood in contact with compost in Canada........................................101 6.6.3. Arsenic levels in garden beds in Twin Cities, Minnesota........................................102 6.6.4. Exposure via leaching from garden borders.............................................................103 6.6.5. Use as wood mulch or soil amendment....................................................................104 6.6.6. Exposure via soil amendment with CCA-treated sawdust.......................................104 6.6.7. Exposure via leaching from vineyard trellis posts...................................................105 6.6.8. Exposure via leaching from support posts and stakes in pots..................................105 6.6.9. Bioavailability and speciation of arsenic in carrots grown in CCA-contaminated soil from a Danish wood preservation site......................................................................................106 6.6.10. Copper, chromium and arsenic levels in vegetables and grasses grown in contaminated soil......................................................................................................................106 6.6.11. Summary and conclusions regarding leaching from CCA treated wood in garden and agricultural situations and plant uptake from contaminated soil..............................................107 6.7. Timber waste during construction...............................................................................108 6.8. Disposal of CCA-treated wood, wood waste and other material containing CCA residues........................................................................................................................................109 6.8.1. Overview..................................................................................................................109 6.8.2. Burning and pyrolysis..............................................................................................110 6.8.2.1. Effect of CCA retention and oxygen supply....................................................110 6.8.2.2. Combustion conditions.....................................................................................111 6.8.2.3. Thermodynamic investigations and minimising arsenic volatilisation losses.111 6.8.2.4. Equilibrium distribution of toxic elements in the burning CCA impregnated wood 112 6.8.2.5. Characteristics of ash from CCA-treated wood...............................................112 6.8.2.6. Determination and analysis of copper, chromium and arsenic in pyrolysis residues 112 6.8.2.7. Industrial scale trials of CCA waste wood incineration in Finland..................113 6.8.2.8. Possible formation of dioxins and furans.........................................................113 6.8.2.9. Incineration in a copper smelter in Finland......................................................114 6.8.2.10. Australian research into combustion of CCA-treated wood............................114 6.8.3. Landfill.....................................................................................................................114 6.8.3.1. Lysimeter studies in Florida.............................................................................114 6.8.3.2. Small scale burial in soil in Japan....................................................................115 6.8.3.3. CCA treatment plant sludge.............................................................................116 6.8.4. Re-use as landscape mulch or soil amendment........................................................116 6.8.5. Other options for the disposal of waste wood and effluent......................................116 6.8.6. Summary and conclusions regarding disposal of CCA treated wood and wood waste 117 6.9. Life cycle analysis of CCA use......................................................................................118 6.9.1. Life cycle analysis of choice of material for utility poles in Sweden......................118 6.9.2. OECD comments.....................................................................................................118 6.10. Summary and conclusions regarding environmental fate......................................118 7. ENVIRONMENTAL EFFECTS..............................................................................120 6/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 7.1. Introduction....................................................................................................................120 7.1.1. Overview..................................................................................................................120 7.1.2. Arsenic.....................................................................................................................121 7.1.3. Chromium................................................................................................................121 7.1.4. Copper......................................................................................................................121 7.2. Birds................................................................................................................................121 7.3. Fish..................................................................................................................................122 7.4. Aquatic Invertebrates....................................................................................................122 7.4.1. Acute toxicity...........................................................................................................124 7.4.2. Chronic toxicity........................................................................................................124 7.4.2.1. Water flea, static renewal 1..............................................................................124 7.4.2.2. Water flea, static renewal 2..............................................................................125 7.4.2.3. Mysid shrimp, low salinity...............................................................................125 7.4.2.4. Mysid shrimp, high salinity..............................................................................125 7.4.2.5. Freshwater sediment invertebrates...................................................................126 7.5. Aquatic Plants.................................................................................................................126 7.6. Terrestrial Invertebrates...............................................................................................129 7.6.1. Toxicity of CCA leachate.........................................................................................129 7.6.2. Toxicity of CCA sawdust to soil invertebrates........................................................129 7.7. Mammals.........................................................................................................................130 7.8. Soil Microorganism Processes.......................................................................................130 7.9. Terrestrial Plants............................................................................................................131 7.9.1. Vegetables in contaminated soil...............................................................................131 7.9.2. Carrots in contaminated soil.....................................................................................132 7.9.3. Seedlings in treated plant boxes...............................................................................132 7.9.4. Ryegrass in contaminated soil..................................................................................132 7.10. Conclusions regarding environmental effects..........................................................133 8. ENVIRONMENTAL RISK ASSESSMENT............................................................134 8.1. Natural background concentrations and contaminated sites.....................................134 8.1.1. Aquatic environment................................................................................................134 8.1.2. Terrestrial environment............................................................................................135 8.1.3. Biota.........................................................................................................................136 8.2. Australian Water Quality Guidelines...........................................................................136 8.3. NEPC Soil Investigation Levels....................................................................................137 8.4. NEPC Groundwater Investigation Levels...................................................................138 8.5. RISK ASSESSMENT – APPLICATION OF CCA TO TIMBER............................138 7/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 8.5.1. Nature of the risks to the environment during CCA treatment of timber................138 8.5.2. Risk assessment of timber preservation plants in the United Kingdom...................138 8.5.3. Evaluations of CCA treatment sites.........................................................................139 8.5.4. Australian sites.........................................................................................................141 8.5.5. Conclusions..............................................................................................................142 8.5.5.1. Overall conclusions regarding risks to the environment from the CCA application process...............................................................................................................142 8.5.5.2. Available guidance...........................................................................................142 8.6. RISK ASSESSMENT – CCA TREATED TIMBER IN USE....................................144 8.6.1. Rate and extent of leaching of CCA components from treated timber....................144 8.6.2. Risk to the environment from elevated arsenic concentrations near treated structures or in run-off water....................................................................................................................146 8.6.3. Possible means of minimising leaching from wood in service................................147 8.6.4. Conclusions regarding risks to the environment from treated wood in service.......148 8.7. RISK ASSESSMENT – DISPOSAL OF CCA-TREATED TIMBER......................148 8.7.1. Overview..................................................................................................................148 8.7.2. Combustion..............................................................................................................149 8.7.3. Leaching...................................................................................................................150 8.7.4. Other options............................................................................................................150 8.8. RISK ASSESSMENT - ARSENIC TRIOXIDE TIMBER TREATMENTS............150 9. CONTROLS/LABELLING.....................................................................................151 9.1. CCA TIMBER TREATMENT PRODUCTS..............................................................151 9.1.1. Australian Guidelines and Standards.......................................................................151 9.1.2. Use manuals.............................................................................................................152 9.1.3. Product labels...........................................................................................................153 9.1.3.1. Current label inconsistencies and inadequacies...............................................153 9.1.3.2. Recommendations for revision of CCA product labels...................................154 9.1.4. Related action – recommendation that CCA be made a Restricted Chemical Product 156 9.2. ARSENIC TRIOXIDE TERMITE TREATMENTS..................................................156 10. RECOMMENDATIONS REGARDING RECONSIDERATION OF REGISTRATION AND LABEL APPROVAL................................................................157 10.1. CCA TIMBER TREATMENT PRODUCTS..........................................................157 10.2. ARSENIC TRIOXIDE TERMITE TREATMENTS..............................................159 11. REFERENCES..................................................................................................160 8/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) 1. INTRODUCTION The scope document for this arsenic wood treatments review indicates that environmental concerns regarding timber treatments mainly relate to the potential contamination of sites where timber has been treated and where disposal of treated timber occurs. CCA has been extensively used in the past as a timber treatment and there are sites that have potentially been contaminated due to leaks and spills from treatment plants or drips from freshly treated timbers. Other possible areas of concern are where treated timbers have been slowly degraded and CCA components released into the ground, with possible subsequent mobility to other areas and effects on non- target organisms. The burning of CCA-treated timber is of environmental concern as the smoke and ash contain high levels of copper, chromium and arsenic, all of which can be toxic to the environment. The NSW EPA submission regarding CCA timber treatments (including comments on behalf of the Environment Protection Heritage Council Waste Working Group) raises issues pertaining to: • the design and management of wood preservation sites, both in regard to environmental protection at the site and proper treatment and fixation of CCA; • impacts from arsenic leaching during use, with those from uses such as structures around houses and playgrounds perceived more as a concern for human health, while potential environmental effects are seen as more of an issue from uses such as boardwalks and other structures in National Parks, jetties and other structures in marine and freshwaters, and possibly electricity poles; • the problems arsenic-treatment creates for the management of waste timber, eg contamination of compost, emission problems if the waste is used for energy recovery, and potential long-term problems if waste is directed to landfill. A submission from K Loveridge of the Croydon Conservation Society claims that the viticulture industry is the largest user of treated pine products in Australia. NSW EPA also raised the specific issue of the large number of CCA-treated posts now being used by the viticulture industry, and the large disposal problem this may lead to in the future. With expansion of the viticulture industry over recent years to 33,000 ha in NSW, and 400-800 posts used per hectare, there are 13.2-26.4 million posts in vineyards. With up to 15% of posts replaced each year due to breakage etc, disposal of CCA-treated timber posts is potentially a large-scale problem. The Department of the Environment and Heritage is aware that this issue is also concerning the South Australian EPA. Similar problems have presumably arisen in other states due to the expansion of the wine grape industry. NSW State Forests noted in its submission that there are potential implications for the use and availability of forest resources. CCA-treated plantation softwood timber products are now being used in many applications where durable hardwoods (eg tallowwood and ironbark) were used previously. This has been important because of the significant reduction in availability of naturally durable timber that has followed the major reduction in logging of native forests in the past 10 years. Better use has also been made of the available hardwood forest resource by using CCA to treat the sapwood component of finished products, particularly heavy timber such as poles, piles and girders. The submission by Osmose (Australia) Pty Ltd also suggests that extending the life of timber by wood preserving techniques reduces the number of trees that may otherwise need to be harvested, and that there are savings in energy and other resources by using treated wood instead of steel, concrete or plastic. 9/173 Australian Pesticides and Veterinary Medicines Authority (APVMA) WHO (2001) observes that arsenic (and other arsenicals) is produced from arsenic trioxide, a by- product of metal smelting operations, and that it has been estimated that 70% of world arsenic production is used in timber treatment as CCA, 22% in agricultural chemicals, and the remainder in glass, pharmaceuticals and non-ferrous alloys. Thus there may be significant implications for world demand for arsenic from falling agricultural and timber treatment use. An increasing proportion of arsenic mined as a by-product with other minerals would then be likely to become mining and smelting waste. Australia has produced arsenic in the past, mainly as a by-product of Western Australian gold mines and a Queensland (Stanthorpe) mine, with some production also in NSW, Victoria and South Australia (in some cases, mines were operated solely for arsenic production, and a major purpose was for production of herbicide to control prickly pear). Since 1952 all of the nation’s requirements have been imported, as it has not been economic to continue mining or processing ore for arsenic production in Australia (Internet http://www.minerals.nsw.gov.au/minfacts/22.htm). This review will concentrate on environmental exposure arising from the wood treatment/fixation process, use in terrestrial situations, and disposal of treated material. Attention will be given to all three elemental components of CCA, though most emphasis will be on the arsenic component. The review will not consider the potential environmental impacts of non-arsenic alternatives to CCA or arsenic trioxide. Information sources which have been used include conference papers, reviews and scientific papers, some website sources and some unpublished reports (often summaries only) of standard ecotoxicity studies. These have largely been provided by the product registrants, with some supplied with public submissions, and some obtained directly for this assessment. 2. CHEMICAL IDENTITY 2.1. COPPER CHROME ARSENATE Common names CCA Copper Chrome Arsenate Chromated Copper Arsenate Chemical name CCA is not a single one substance, but a mixture in water solution of inorganic components containing the elements copper (II), chromium (VI) and arsenic (V). Various ratios of these elements in the form of oxides or salts have been or are still available (Section 4.1). CAS Registry number There appears to be no CAS number for CCA, but CAS numbers are listed below for the individual components used in Australian CCA formulations (Table 1). 10/173