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Increasingly stringent regulations regarding waste disposal encourage the development of options for reuse, recycling and revalorisation of waste. Metals-bearing treated wood wastes are no exception. Previous studies identified a possible treatment technology for chromated copper arsenate (CCA) preservative-treated wood waste based on sulphuric acid leaching. In this study, the scale-up of this technology was extended from 200 ml flask to 80 l working volume stirred-tank reactor. The study involved three leaching steps of 2 h each, at 75 °C with 0.2 N H2SO4 and 15% solids content followed by three rinsing steps. This procedure led to removal of 99.5% of the arsenic, 95.7% of the chromium and 99.6% of the copper from the wood chips on average. The effluents generated by the leaching steps were then treated by precipitation. This technology allowed 99% removal of As, Cr and Cu from the leachate, leading to effluents satisfying the regulations for effluent discharge in municipal sewers. The mass balance was assessed for the whole process (leaching, rinsing and precipitation of the leachate) and the output to input ratio was between 80% and 100%. Furthermore, the economic analysis concluded that the operating cost of the process (leaching, rinsing and precipitation of the leachate) was about 250 $/ton of treated wood (t.t.w.) with the conditions employed in this study. However, the cost could be reduced at least to 89 $/t.t.w. by using a counter current leaching process as developed in a previous study.

Claddings or facades are the outer part of building envelopes. In this study, wooden claddings are exposed to natural and accelerated weathering. The natural climate exposure was performed at a field test site located in Trondheim, Norway. Accelerated climate exposure was performed in the laboratory in an Atlas SC600 MHG solar simulator. Attenuated total reflectance – Fourier transform infrared (ATR-FTIR) spectroscopy was used to characterise surfaces. The objective was to assess degradation by use of FTIR and thereby see how this may be applied to evaluate the service life of wood. Four types of wooden materials were studied; three untreated and one treated with chromated copper arsenate. Surface concentrated cellulose and lignin are the primary wood components used to determine the quality and durability of wood during ageing. It was found that treatment with preservative chemicals and surface roughness has definitive impacts on cladding surfaces and change to the chemical properties of the materials during ageing. The acceleration factor deduced from the Arrhenius equation shows that an increase in temperature lowers the service life of cellulose at a higher rate than the other wood components. (c) ICE Publishing: All rights reserved.

Recovered wood is frequently contaminated with biocides and therefore its use is limited. Even more, wood, impregnated with classical chromated copper arsenate (CCA) preservatives is classifi ed as a hazardous waste, therefore solutions for reuse or recovery of this material are sought. One of the options, discussed in this paper is liquefaction and further applications of liquefi ed wood containing biocide remainings. In order to elucidate this possibilty, spruce and beech wood was impregnated with liquefi ed CCB treated and untreaded spruce wood of various concentrations and exposed to wood decay fungi according to the EN 113 procedure. In paralel, the leaching experiments (ENV 1250-2) were performed as well. The results do not clearly show that liquefi ed wood is bio-inactive. In most cases the mass loss by fungal attack is decreased compared to the untreated controls. On the other hand, copper leaching from spruce wood, impregnated with the liquefi ed CCB treated wood was signifi cantly reduced. Thus, there are indications that the liquefi ed wood could be utilized as a binding agent for inorganic biocides.

Soils adjacent to chromated copper arsenate (CCA)-treated fence posts along a fence line transecting different soil series, parent material, drainage classes, and slope were used to determine which soil properties had the most influence on As spatial distribution and speciation. Metal distribution was evaluated at macroscopic (total metal concentration contour maps) and microscopic scales (micro-synchrotron X-ray fluorescence maps), As speciation was determined using extended X-ray absorption fine structure spectroscopy, and redox status and a myriad of other basic soil properties were elucidated. All geochemical parameters measured point to a condition in which the mobilization of As becomes more favorable moving down the topographic gradient, likely resulting through competition (Meh-P, SOM), neutral or slightly basic pH, and redox conditions that are favorable for As mobilization (higher Fe(II) and total-Fe concentrations in water extracts). On the landscape scale, with hundreds of kilometers of fence, the arsenic loading into the soil can be substantial (∼8-12 kg km). Although a significant amount of the As is stable, extended use of CCA-treated wood has resulted in elevated As concentrations in the local environment, increasing the risk of exposure and ecosystem perturbation. Therefore, a move toward arsenic-free alternatives in agricultural applications for which it is currently permitted should be considered.

This paper compares two methods of measuring the corrosion of steel and galvanized steel in wood: a long-term exposure test in solid wood and a rapid test method where fasteners are electrochemically polarized in extracts of wood treated with six different treatments. For traditional wood preservatives, the electrochemical extract method correlates with solid wood exposure which suggests that the reduction of cupric ions is the cathodic reaction in both the solid wood and the extract. For treatments without copper, the extract method predicted a higher corrosion rate than the solid wood exposure. For these treatments, the cathodic reaction appears to be the reduction of acid and dissolved oxygen. The practical implication of this work is that in some cases, the rapid test method could be used to screen new fasteners and wood preservatives. Scientifically, this work increases the understanding of the mechanism of corrosion of fasteners in treated and untreated wood.

Structures made of chromated copper arsenic (CCA) have been shown to leach arsenic into the surrounding soil. Soil cores were taken adjacent to six CCA decks at 0, 15, 60 and 300 cm from the deck at depths of 0-10, 10-20, and 20-30 cm, and were analyzed for soil arsenic concentrations. Median soil arsenic concentrations ranged from 1.8 μg/g at a depth of 10-20 cm and a distance of 300 cm to 34.5 μg/g at a depth of 0-10 cm and a distance of 30 cm. Soil arsenic concentrations taken at depths of 0-10 and 10-20 cm decreased as distance from the deck increased. Soil arsenic concentrations close to the deck were higher at lower soil depths and at homes with greater deck wipe arsenic concentrations. Age of deck and slope of land had significant effects on the differences in arsenic concentrations between samples taken at different distances when evaluated in models by themselves, but not in models adjusting for deck wipe concentrations. Size of deck and bulk density of soil did not have significant effects on soil arsenic concentrations.

Understanding how a coating’s properties are related to its performance characteristics and how measuring its properties can be used for predicting the performance of coating in service was the main focus of this study. A number of exterior penetrating wood stains were characterized in terms of glass transition temperature (T g), solid content, viscosity, and surface tension. The contact angles of liquid coatings were measured on wood treated with chromated copper arsenate, alkaline copper quat, and copper azole as well as untreated wood. Also, the film thicknesses of the cured coatings on wood surfaces were measured by back-scattered electron imaging of osmium-treated samples. Partial least square-regression (PLS-R) modeling was used to correlate measured coating properties with their weathering performance on the preservative-treated and untreated wood substrates, based on water repellency, color retention, and visual ratings after 3 years of natural weathering. A PLS model was developed with 77% fitting accuracy and 69% prediction ability. This model indicated that preservative treatments significantly affected coating performance, and among coating properties, film thickness, viscosity, and glass transition temperature had the greatest effects on the coatings’ performance in exterior.

Pressure-treated lumber available for residential applications had been changed from chromated copper arsenate (CCA) treatment to Cu–amine formulations (since January 2004). This change created a need to investigate the performance of coatings on these new Cu-based preservatives as compared with CCA. This study evaluated performance of a number of semitransparent deck stains on CCA, alkaline copper quat (ACQ), copper azole (CA), and untreated wood samples during 3 years of natural weathering. Coatings were evaluated for their ability to reduce water uptake, color change, checking of wood, and mildew growth and to improve general appearance of preservative-treated wood samples. Overall, Cu–amine-treated wood had on average 50% higher water uptake than CCA-treated wood samples. Although solvent-based coatings had better water repellency performance on CCA-treated and untreated wood, there was no significant difference in water-repellent effectiveness (WRE) between water-based and solvent-based coatings on ACQ- or CA-treated wood. All preservative-treated woods had less color change and better visual ratings than those of untreated wood samples. Based on image analysis which was used to determine the total area of surface checking on samples after 3 years, preservative treatments had no significant effect on reducing checking of wood while coatings reduced surface checking by 30–40%.

Waste wood is frequently contaminated with wood treatment preservatives including chromated copper arsenate (CCA) and alkaline copper quat (ACQ), both of which contain metals which contaminate recycled wood products. The objective of this research was to propose a design for online automated identification of As-based and Cu-based treated wood within the recovered wood waste stream utilizing an X-ray fluorescence (XRF) system, and to evaluate the detection parameters of such system. A full-scale detection unit was used for experimentation. Two main parameters (operational threshold (OT) and measurement time) were evaluated to optimize detection efficiencies. OTs of targeted metals, As and Cu, in wood were reduced to 0.02 and 0.05, respectively. The optimum minimum measurement time of 500 ms resulted in 98%, 91%, and 97% diversion of the As, Cu and Cr mass originally contained in wood, respectively. Comparisons with other detection methods show that XRF technology can potentially fulfill the need for cost-effective processing at large facilities (>30 tons per day) which require the removal of As-based preservatives from their wood waste stream.

The interactions of alkaline copper quat (ACQ) components with the earlywood and latewood tissues of southern pine were investigated. There was a highly significant redistribution of the copper amine component from the earlywood to the latewood during post-treatment fixation at 50°C, which was mainly attributed to diffusion of copper amine from the earlywood into the latewood. A small amount of copper amine redistributed between the tissues and toward the wood surfaces during drying following fixation. The redistribution within the wood was similar whether the preservative penetrated longitudinally, tangentially, or radially into the wood during pressure treatment. This redistribution resulted in lower solubility of copper, and this effect contributes to the overall copper fixation in ACQ-treated wood. The quat component did not significantly diffuse after treatment, and its concentration remained much higher in the earlywood compared to the latewood.

The impact of storm water run-off from a location of intensive application of CCA in wood treatment on the quality of sediment of the receiving water body was examined. Sediment samples were collected along Ogba River. Physico-chemical characteristics as well as total levels of As, Cr and Cu in sediment samples were determined. Physico-chemical analysis of composite sediment samples upstream and downstream showed pH of sediments to be neutral (6.95 upstream and 6.90 downstream). The sand content for downstream sediment was 90.52 and 87.52% for upstream sediment sample. Total levels of 3.3–14.9 mg kg−1 As, 3.1–116.6 mg kg−1 Cr, and 13.7–16.4mg kg−1 Cu were obtained for downstream sediment samples and 2.2–2.3mg kg−1 As, 8.1–13.1 mg kg−1 Cr, and 6.0–7.4mg kg−1 Cu were obtained for upstream samples. Sequential extraction procedure involving six steps was used to evaluate the partitioning of As, Cr and Cu in the sediments. The results showed that the bioavailable fraction of sediment 20 m downstream wa...

Laminated utility pole crossarms constitute one of the potential industrial products that can be produced from decommissioned wood utility poles. A previous report evaluated the mechanical properties of laminated utility pole crossarms made from decommissioned chromated copper arsenate (CCA)―treated southern pine (Pinus spp.) utility pole wood, untreated virgin wood, and a mixture of virgin wood and decommissioned utility pole wood. In particular, the bending strength, stiffness, and acoustic properties were assessed after pentachlorophenol (penta) retreatment. This study evaluated CCA and penta retention, glue-line shear, and glue-line delamination of the laminated crossarms. The results of this study show that, after penta retreatment, penta retention increased in correlation to the presence of increasing numbers of treated wood plies in the beams. All the laminated crossarms met the minimum shear strength requirement of 8.60 MPa, which is specified in American Society for Testing and Materials (ASTM) Standard D2559. Most of the laminated crossarms (22 of 24) showed a delamination average of less than 5 percent. However, none of the beams met the individual glue-line delamination requirement (1%) of ASTM Standard D2559. More glue-line delamination was found between two utility pole wood plies and between a utility pole wood ply and a virgin wood ply than between two virgin wood plies. Delamination could be a concern for utility pole wood laminated crossarms to be used in an adverse environment. A better gluing system is needed to improve the delamination performance of utility pole wood laminated beams for exterior applications.

Soil ingestion is an important pathway for exposure to metals for children. The objectives of this study were to: (1) Assess urban soil contamination by selected metals (As, Cr, Cu, Ni, Pb, and Zn) in 24 sites (127 soil samples) in Istanbul, Turkey, (2) Investigate relationships between soil contamination and site properties (type of site, equipment type, soil properties), (3) Characterize the risk for critically contaminated sites by taking oral metal bioaccessibility and two soil ingestion scenarios into account. Average metal concentrations were similar in the 17 playgrounds, 4 parks and 3 picnic areas sampled. Five out of 24 sites (all equipped with treated wood structures) had systematically higher contamination than background for As, Cu, Cr or Zn, and measured concentrations generally exceeded Turkish regulatory values. High Cu concentrations in these sites were attributed to the leaching from wood treated with Cu-containing preservatives other than chromated copper arsenate (CCA). Risk characterization for these sites showed that hazard index was below one in both involuntary soil ingestion and soil pica behaviour scenarios for all metals. However, probabilistic carcinogenic risk for As uptake exceeded 1 × 10−6 in both scenarios. A sensitivity analysis showed that soil ingestion rate was the most important parameter affecting risk estimation. Risk from As uptake for children from soils of parks, playgrounds and picnic areas may be serious, especially if soil pica behaviour is present.

The efficiency of semitransparent penetrating stains to reduce leaching of wood preservative components was evaluated. Five commercial wood deck finishes were applied to untreated and chromated copper arsenate (CCA), alkaline copper quat (ACQ), and copper azole (CA) treated wood, and leachates were collected and analyzed during 3 years of natural weathering exposure in Toronto, Canada. All stains evaluated effectively reduced the cumulative leaching of all inorganic preservative components by about 60% on average. Although most coatings showed significant film degradation starting around 12 months, the reduced leaching persisted even after 3 years. This suggests that temporary protection of wood with a coating during the early stages of use resulted in long-term reduction in preservative leaching potential. A two-week screening leaching test was able to predict the long-term leaching performance of different coatings reasonably well. Cured coating glass transition temperature (Tg) and liquid coating viscosity were the most important variables affecting a leaching prediction model. To effectively reduce leaching of preservative components from treated wood, coatings should have Tg low enough to withstand stresses caused by freezing in winter and have adequate viscosity to form a barrier film layer on the wood surface.

Chromated copper arsenate (CCA) was widespread used as a chemical wood preservative with application in the construction of playground equipment, fences, jetties, and naval. Environmental protection agency (EPA) had limited the use of CCA-treated wood on 2002, due to probable implications on both human and environmental health. Although this fact, several industries pursue the use of this product within their manufactories. In addition, the durability of this wood for 60 years, makes these treated products an hazard to the public health. In the present work, studies were explored exposing mice to CCA, during 14, 24, 48, and 96 h for the assessment of acute toxicity of CCA. Kidney and liver were removed, prepared for histology and for metalloid, and copper content evaluation by high resolution inductively coupled plasma mass spectroscopy. The histological results evidenced apparently normal structures for control animals and group exposed to As2O5. On the contrary, the renal sections of the animals treated with CCA revealed epithelium cells desquamation, hyaline, and granular casts in renal tubules lumen. Furthermore, high levels of arsenic were detected in the kidney of animals treated with CCA over 14 and 48 h, being significantly greater than controls. Although this approach underlines the potential hazard of CCA on some vital organs, further testing may be required to establish the impacts on other functions.

Radiata pine (Pinus radiata) peeler cores are classified as a by-product of plywood manufacture and have the potential for development as value-added solid wood products. This article outlines technical and cost analyses of microwave surface modification of radiata pine peeler cores along with the methodology, including measurements of temperature distribution and of preservative uptake and distribution following microwave heating. After microwave treatment, the highest temperatures are observed on the surfaces of the peeler cores. A gradual decrease in temperature is noted with depth within the timber. Chromated copper arsenate uptake after pressure impregnation ranges between 94 and 314 liters/m 3 . This uptake is three to nine times higher than that of control timber (no microwave treatment). Cost analyses focus on the microwave treatment of peeler cores and indicate that microwave modification costs range from US$0.95 to US$1.23 for one peeler core (i.e., US$29 to US$37 per m 3 ), depending upon electricity charges and the number of working shifts employed.

Samples of new and weathered utility lumber pressure-treated with chromated copper arsenate (CCA) were tested for leaching of copper, chromium and arsenic by submersion in leaching baths of various pH levels. Accumulation of metals was monitored in leachate at pH 3.5, 4.5, 5.5, 7.0 and 8.5 over a period of 40 d by atomic absorption spectroscopy. Copper, chromium and arsenic were found in the leachate of both new and weathered wood with significantly higher levels of all metals occurring at acidic pH levels. Up to 100% of CCA treatment metals were found to have leached at pH 3.5, whereas a maximum of 9% of metals leached at pH 8.5. Metal leaching was found to be higher in citric acid than in dilute sulfuric acid solutions. Leaching of copper, chromium and arsenic was not proportional to the amount of metal present before leaching.

Children may be exposed to arsenic during contact with structures treated with chromated copper arsenate (CCA). A high frequency of hand-to-mouth activity may increase their risk of ingesting arsenic. Previous work showed that arsenic concentrations in the hand-wash samples of children playing on CCA playgrounds were four times higher than those playing on non-CCA playgrounds. It is not clear whether playing on CCA playgrounds results in elevated overall exposure to arsenic. The objective of this study was to perform arsenic biomonitoring in children to determine whether playing on CCA-treated playgrounds substantially contributes to their overall exposure to arsenic. One hundred and twenty five saliva samples from 61 children and 101 urine samples from 45 children were collected after children played on 8 CCA and 8 non-CCA playgrounds. Arsenic speciation analysis was conducted using high performance liquid chromatography combined with inductively coupled plasma mass spectrometry. The arsenic species detected in the urine and saliva samples from children playing on CCA and non-CCA playgrounds were similar. Dimethylarsinic acid and arsenobetaine were the main arsenic species found in urine samples. The sum of inorganic trivalent and pentavalent arsenic, monomethylarsonic acid, and dimethylarsinic acid in urine was 15 +/- 28 microg/L in the CCA group and 12 +/- 23 microg/L in the non-CCA group (p = 0.60). The sum of these species in saliva was 1.1 +/- 2.1 microg/L in the CCA group and 1.4 +/- 1.1 microg/L in the non-CCA group (p = 0.32). These results show that there is no significant difference in the concentration or speciation of arsenic between the samples from children playing on CCA and non-CCA playgrounds. Contact with CCA playgrounds is not likely to significantly contribute to the overall arsenic exposure in children; other sources such as dietary arsenic may be a main contributor to their overall exposure.

Inorganic arsenic in soils poses an important environmental concern. Several studies reported an oxidation of arsenite to arsenate during its extraction from soils. The objectives of this study were to (1) identify, among published procedures, an extraction method which preserves the oxidation state of arsenic and (2) to assess the influence of soil physicochemical properties on the performance of these methods. Four extraction strategies were compared: 1) 10 M HCl, 2) 15% (v/v) H 3 PO 4 , 3) 10 mM phosphate + 0.5% (w/v) NaDDC, and, 4) 1 M H 3 PO 4 + 0.5 M ascorbic acid (C 6 H 8 O 6 ). Separation and analysis of As species was performed by HPLC-ICP/MS. Oxidation of As(III) into As(V) during extraction was more important in soils with high content of Mn oxides. Extraction of arsenic from soils with 1 M H 3 PO 4 + 0.5 M C 6 H 8 O 6 under microwaves was the best strategy to extract the majority of As while minimizing conversion of As(III) into As(V).

This study looks into the potential risks of arsenic, chromium, and copper leaching from disposed hardwoods treated with chromated copper arsenate (CCA) in a tropical climate. The Toxicity Characteristic Leaching Procedure (TCLP) and the Waste Extraction Test (WET) were employed to examine new CCA-treated Burseraceae and Keruing woods, weathered CCA-treated teak wood, and ash from new CCA-treated Burseraceae wood. In addition, a total of six lysimeters, measuring 2 m high and 203 mm in diameter were prepared to compare the leachate generated from the wood monofills, construction and demolition (CD) debris landfills and municipal solid waste (MSW) landfills, containing CCA-treated Burseraceae wood. The TCLP and WET results showed that the CCA-treated Burseraceae wood leached higher metal concentrations (i.e. 9.19-17.70 mg/L, 1.14-5.89 mg/L and 4.83-23.89 mg/L for arsenic, chromium, and copper, respectively) than the CCA-treated Keruing wood (i.e. 1.74-11.34 mg/L, 0.26-3.57 mg/L and 0.82-13.64 mg/L for arsenic, chromium and copper, respectively). Ash from the CCA-treated Burseraceae wood leached significantly higher metal concentrations (i.e. 108.5-116.9 mg/L, 1522-3862 mg/L and 84.03-114.4 mg/L for arsenic, chromium and copper, respectively), making this type of ash of high concern. The lysimeter study results showed that the MSW lysimeter exhibited higher reducing conditions, more biological activities and more dissolved ions in their leachates than the wood monofill and CD debris lysimeters. All leachates generated from the lysimeters containing the CCA-treated Burseraceae wood contained significantly higher concentrations of arsenic in comparison to those of the untreated wood: in the range of 0.53-15.7 mg/L. It can be concluded that the disposal of CCA-treated Burseraceae wood in an unlined CD landfill or a MSW landfill has the potential to contaminate groundwater.

The research presented in this paper evaluates the potential impact of municipal solid waste (MSW) landfill leachate quality on the loss of metals from discarded treated wood during disposal. The loss of arsenic (As), chromium (Cr), copper (Cu), and boron (B) from several types of pressure-treated wood (CCA: chromated copper arsenate, ACQ: alkaline copper quaternary, CBA: copper boron azole, and DOT: disodium octaborate tetrahydrate) using leachate collected from 26 MSW landfills in Florida was examined. The toxicity characteristic leaching procedure (TCLP), the synthetic precipitation leaching procedure (SPLP), and California's waste extraction test (WET) were also performed. The results suggested that loss of preservative components was influenced by leachate chemistry. Copper loss from CCA-, ACQ- and CBA-treated wood was similar in magnitude when in contact with landfill leachates compared to synthetic TCLP and SPLP solutions. Ammonia was found as one of the major parameters influencing the leaching of Cu from treated wood when leached with MSW landfill leachates. The results suggest that disposal of ACQ- and CBA-treated wood in substantial quantity in MSW landfills may elevate the Cu concentration in the leachate; this could be of potential concern, especially for a bioreactor MSW landfill in which relatively higher ammonia concentrations in leachate have been reported in recent literature. For the As, Cr and B the concentrations observed with the landfill leachate as the leaching solutions were over a range from some sample showing the concentrations below and some showing above the observed value from corresponding SPLP and TCLP tests. In general the WET test showed the highest concentrations.

A solid, crystalline fumigant (dazomet) with and without a supplemental copper compound was evaluated as an internal decay control treatment on Douglas-fir poles in two long-term field tests. Methylisothiocyanate (MITC), the decomposition product of dazomet, was used as a measure of effectiveness. MITC levels in the wood were above the threshold near the groundline application zone within 1 year after treatment. MITC levels above the groundline were much lower, suggesting that the treatment zone would need to be extended to produce protection in these higher zones. The addition of copper sulfate markedly increased MITC levels. Copper naphthenate was slightly less effective as a dazomet accelerant, but slightly better than dazomet alone. The results indicate that dazomet treatment remains at protective levels for 10 to 12 years. This range is well within the typical inspection cycle used by most North American utilities.

The reusability of decommissioned treated wood is primarily dependent on the residual strength of the wood after service. Determining the residual strength can provide useful information for structural design and reuse of the decommissioned treated wood. This study evaluated the residual strength of decommissioned chromated copper arsenate–treated utility pole wood. Eleven decommissioned southern pine (Pinus spp.) distribution poles and pole sections were evaluated, using small clear samples, for bending strength and stiffness across and along each pole. Results showed that the strength of the decommissioned treated wood varied across and along each pole and among the poles. Average modulus of rupture (MOR) was 80.9 percent of the typical MOR of longleaf pine (Pinus palustris) virgin wood, and average modulus of elasticity (MOE) was 83.9 percent of the typical MOE. Average MOR of the samples in the outer surface (first test zone) was 7.5 percent lower than the average MOR of the adjacent samples toward th...

In recent years, rising concern over the disposal of preservative treated wood has generated interest in the reuse and recycling of this biomass resource. The primary objective of this study was to evaluate the bending strength and stiffness of laminated crossarms consisting entirely of virgin wood, entirely of decommissioned chromated copper arsenate (CCA)–treated utility pole wood, or a mixture of virgin wood and decommissioned CCA-treated utility pole wood after treatment with pentachlorophenol (penta). The secondary objective was to correlate acoustic properties of the laminated crossarms with their mechanical properties. Solid sawn virgin wood crossarms, solid sawn crossarms cut from decommissioned CCA-treated utility pole wood, and the laminated crossarms were evaluated for strength, stiffness, strain, and acoustic properties. The solid sawn virgin wood crossarms and all compositions of laminated crossarms met the American National Standards Institute minimum strength requirement. Only the solid saw...

Environmental accumulation of preservative adjacent to a chromated copper arsenate (type C)–treated wetland boardwalk was evaluated. The site is considered a realistic ‘‘worst case’’ because of the large volume of treated wood, low current speeds, high annual rainfall, and environmental sensitivity. Soil and sediment samples were collected before construction and 0.5, 2, 5.5, 11, 24, 60, and 131 months (11 y) after construction and analyzed for total chromium, copper, and arsenic concentrations. This article updates the findings after 11 years of exposure. Environmental concentrations varied with time, with proximity to the treated wood, and between riparian and aquatic locations. Concentrations of leached components in the soil developed slowly, were greatest at the 60-month sampling, and declined at the 131-month inspection. Soil samples with elevated levels of copper and chromium were confined to directly under the drip line of the boardwalk, and arsenic appeared to be limited to within 0.3 m (1 ft) of the structure. Concentrations of leached components in the sediments increased more quickly than those in the soil and tended to reach maximum or near maximum levels within the first year. However, concentrations of arsenic and copper in sediments directly under the walkway reached maximum levels after 60 months, before declining at the 131-month sampling. Elevated concentrations of copper, chromium, and arsenic were occasionally found in sediments as much as 3 m (10 ft) from the boardwalk.

Three soil samples contaminated by chromated zinc arsenate (CZA) or chromated copper arsenate (CCA) were investigated in a laboratory scale to study As mobilization and to identify a chemical agent that could be used in soil washing to extract arsenic. Besides high As extraction, the cost, occupational health issues and technical aspects were considered when selecting the chemical. Arsenic is strongly bound to CZA/CCA soils; only ∼50% of the tot-As was removed from water-washed soils. High Fe or Al mobilization is not necessarily indicative of high As removal from CZA/CCA soils. A high Cu/As-ratio and a large amount of soluble Ca in the soil hampered As extraction. The high ratio can be an indication of stable Cu-arsenates in soil. Calcium can react with the extraction agent or with As during extraction. Sodium hydroxide, dithionite with citrate (and oxalate) (dithionite solutions), and oxalate with citrate were the most efficient chemicals for removing As from the soils. The disadvantages of using these ...

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Arsenic (As) is known to be very toxic and carcinogenic to human beings. Arsenic contaminated soil was collected from a timber mill site at Busan Metropolitan City, Korea, where chromated copper arsenate (CCA) had been used to protect wood from rotting caused by insects and microbial agents. The soil was stabilized using both natural oyster shells (NOS) and calcinated oyster shells (POS). The calcination of natural oyster shells was accomplished at a high temperature in order to activate quicklime from calcite. Two different oyster shell particle sizes (-#10 mesh and -#20 mesh) and curing periods of up to 28 days were investigated. The stabilization effectiveness was evaluated based on the Korean Standard Test (KST) method (1N HCl extraction). The stabilization results showed that the POS treatment was more effective than the NOS treatment at immobilizing the As in the contaminated soils. A significant As reduction (96%) was attained upon a POS treatment at 20 wt% and passed the Korean warning standard of 20 mg/kg ('Na' area). However, an As reduction of only 47% (169 mg/kg) was achieved upon a NOS treatment at 20 wt%. The -#20 mesh oyster shells seem to perform better than the -#10 materials. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results showed that As immobilization was strongly associated with Ca and O in the presence of Al and Si.

Chromated copper arsenate (CCA) is a chemical wood preservative that has been intensively used to protect wood from decay during the last few decades. CCA is widely used to build structures such as decks, fences, playgrounds and boardwalks. However, structures constructed of CCA-treated wood have caused adverse environmental effects due to leaching of Cr, Cu and As into surrounding soils. This research was conducted to monitor the vertical and horizontal distribution of Cr, Cu and As in soils adjacent to CCA-treated wood structures in Korea. Two structures constructed with CCA-treated wood were selected at Hongcheon and Chuncheon in Gangwon Province, South Korea. Eleven soil profile samples were collected at depths of 0 to 80 cm at each site, while 12 surface soil samples were collected at distances of 0 to 200 cm from each structure. The soil chemical properties, soil particle size distribution and total metal concentrations were then determined. The results revealed that soils near CCA-treated wood structures were generally contaminated with Cr, Cu and As when compared to the background concentration of each metal. In addition, the concentrations of Cr, Cu and As in soils decreased as the vertical and horizontal distance from the structure increased. Further studies should be conducted to evaluate the mobility and distribution of these metals in the environment as well as to develop novel technologies for remediation of CCA contaminated soils.

Significant amounts of chromated copper arsenate (CCA) treated wood products, such as utility poles and residential construction wood, remain in service. There is increasing public concern about environmental contamination from CCA-treated wood when it is removed from service for reuse or recycling, placed in landfills or burned in commercial incinerators. In this paper, we investigated the effects of time, temperature and sodium hypochlorite concentration on chromium oxidation and extraction of chromated copper arsenate from CCA-treated wood (Type C) removed from service. Of the conditions evaluated, reaction of milled wood with sodium hypochlorite for one hour at room temperature followed by heating at 75 degrees C for two hours gave the highest extraction efficiency. An average of 95% Cr, 99% Cu and 96% As could be removed from CCA-treated, milled wood by this process. Most of the extracted chromium was oxidized to the hexavalent state and could therefore be recycled in a CCA treating solution. Sodium hypochlorite extracting solutions could be reused several times to extract CCA components from additional treated wood samples.

In the past, gravimetric corrosion data for fasteners exposed to treated wood has been reported as a percent weight loss. Although percent weight loss is a valid measure of corrosion for comparing identical fasteners, it can distort the corrosion performance of fasteners with different geometries and densities. This report reevaluates a key report on the corrosiveness of wood treated with chromated copper arsenate (CCA) and ammoniacal copper arsenate (ACA) and converts the previous data into corrosion rates. In addition, similar experiments were run in wood treated with alkaline copper quaternary (ACQ). Comparison of the corrosion rates reveals ACQ treated wood is more corrosive than CCA treated wood for every metal. The corrosion rate of aluminum was found to be lower than both hot-dip galvanized steel and electroplated galvanized steel in ACQ, ACA, and CCA treated wood. In ACA and ACQ treated wood, the electroplated galvanized fastener had a lower corrosion rate than the hot-dip galvanized fastener.

Disposal of decommissioned chromated copper arsenate (CCA-treated wood as landfill has become an important environmental concern. Reusing and recycling decommissioned treated wood seems to be the most practical environmental solution to the problem. In a previous report, 6-ply laminated beams made from decommissioned CCA-treated southern pine (Pinus spp.) wood utility poles and 6-ply laminated beams made from untreated virgin wood were studied to evaluate the effects of surface preparation method and cross-sectional region (high or low CCA retention) on bonding shear strength, wood failure, and delamination. In this study, 6-ply laminated beams having the same composition as those of the previous study were made and then pressure-treated (i.e., retreated) with CCA prior to being evaluated in the same manner as in the previous study. This study revealed that gains in CCA retention (as a result of retreatment with CCA) for beams made from decommissioned utility pole wood were similar to the gains for beams made from untreated virgin wood. CCA retreatment had little overall effect on either glue-line shear strength or wood failure of beams made from decommissioned wood utility poles, but overall substantially increased shear strength and wood failure of beams made from virgin wood. CCA retreatment also reduced the delamination of both beams made from decommissioned utility pole wood and beams made from virgin wood. Additional testing is warranted to further investigate the bonding performance of decommissioned CCA-treated transmission utility pole wood.

Chromated copper arsenate (CCA)-treated wood was liquefied with polyethylene glycol/glycerin and sulfuric acid. After liquefaction, most CCA metals (98% As, 92% Cr, and 83% Cu) were removed from liquefied CCA-treated wood by precipitation with calcium hydroxide. The original CCA-treated wood and liquefied CCA-treated wood sludge were fractionated by a modified Community Bureau of Reference (BCR) sequential extraction procedure. The purpose of the BCR-sequential extraction used in this study was to examine the availability of CCA metals in treated wood for reuse. Both As and Cr had a slightly higher concentration in the sludge sample than in original CCA-treated wood. The sequential extraction showed that As and Cr were principally existed in an oxidizable fraction (As, 67%; Cr, 88%) in original CCA-treated wood. Only 1% of both As and Cr were extracted by hot nitric acid with the last extraction step. The distribution of As and Cr changed markedly in liquefied CCA-treated wood sludge. The amount of As in the exchangeable/acid extractable fraction increased from 16% to 85% while the amount of Cr increased from 3% to 54%. Only about 3% of As was present in the oxidizable fraction. However, there was still about 34% of Cr in the same fraction. Based on these results from sequential extraction procedures, it can be concluded that the accessibilities of CCA metals increase markedly by the liquefaction-precipitation process.

Reaction kinetics of fixation of CCA-C (chromated copper arsenate type C) preservative was studied at 30°C in ground wood of trembling aspen, red pine, and red maple at treatment retentions of 4.0, 6.4, 9.6, and 30 kg/m3, and red maple pre-extracted with hot water at retentions of 6.4 and 30 kg/m3. Reaction orders of cumulative Cr, Cu, and As reactions decreased gradually during the fixation if calculated by Van’t Hoff’s method. With Essen’s method, CCA fixation was best approximated as follows: Cr—3rd order reaction during the first 24 h, and 1st order reaction for the rest of the fixation period; Cu—2nd order reaction; and As—1st order reaction in red pine and aspen, and 2nd order in red maple. Rates of reaction decreased with increased CCA solution concentration for Cr and Cu, and increased for As, except in red maple. Reaction rates for all CCA elements were significantly higher in rapidly fixing red maple than in regularly fixing red pine and aspen, and were higher in unextracted than pre-extracted red maple. Modeling of CCA fixation kinetic for the whole fixation period enabled comparison of fixation reactions among wood species, preservative components, and treatment retentions.

The thermal stability and desorption of arsenic trioxide (As2O3) adsorbed on activated carbon (AC) was investigated as this phenomenon is expected to influence the arsenic release during low temperature pyrolysis of chromated copper arsenate (CCA) wood waste. Firstly, a thermogravimetric (TG) experiment with arsenolite, an allotropic form of As2O3, was performed. The sample starts to sublime at temperatures lower than 200,C with a sublimation peak temperature of 271 degrees C. Subsequently, TG experiments with samples of As2O3 adsorbed on AC revealed that only very little (max. 6 +/- 3 wt%) As2O3 was volatilised at temperatures below 280 degrees C, while still 41.6 (+/- 5)wt% of the original arsenic concentration was retained at 440 degrees C and 28.5 (+/- 3) wt% at 600 degrees C. The major arsenic volatilisation occurred between 300 degrees C and 500 degrees C. The kinetic parameters of desorption, activation energy of desorption (E-d) and pre-exponential factor (A), were determined by fitting an Arrhenius model to the experimental data, resulting in E-d = 69 kJ/mol, A = 1.21 x 10(4) s(-1). It can be concluded that the adsorption of As2O3 on AC can contribute to the thermal stabilisation of As2O3, Consequently, during low temperature pyrolysis of CCA wood arsenic release may be prevented by adsorption of As2O3 on the coal-type product formed during the thermal decomposition of the wood. (C) 2008 Elsevier B.V. All rights reserved.

The leaching of chromated copper arsenate (CCA) components from unfixed wood immersed in water is modeled in three dimensions using an analytical model of simultaneous diffusion and reaction. Parameters for the model were determined by laboratory leaching experiments with small uncoated wood samples, departing from previous approaches where diffusion coefficients are measured in one dimension at a time. The diffusion coefficients and reaction rate constants of Cr6+, total Cr, Cu, and As in unfixed CCA-treated red pine (Pinus resinosa Ait.) and southern pine (Pinus sp.) were estimated, assuming first-order reaction rate equations and independent Fickian diffusion for all components. Estimated reaction rate constants and diffusion coefficients were not significantly affected by sample dimensions except for very severe longitudinal leaching from short samples. The predictive ability of the model using diffusion coefficients determined from immersion of small lab samples was evaluated by leaching experiments in a spray booth of southern pine lumber at 21 and 60°C, and red pine pole sections at 21°C. The predictive ability of the model was mixed, but in all cases represents a significant improvement over small-block leaching models which do not account for the diffusive nature of the leaching process.

The burning of wood treated with chromated copper arsenate (CCA) produces an ash that contains high concentrations of copper, chromium, and arsenic. The subsequent leaching of these metals from burn sites can produce soil and water contamination. Soils have varying natural abilities to reduce leaching and impact metals speciation and toxicity by sorption, conversion, and sedimentation-related mechanisms. Recent regulations have resulted in increased quantities of CCA-treated lumber entering the waste stream, making the study of metals leaching from ash, and the amendment of soils to more effectively immobilize metals, important areas of investigation. The performance of various soil amendments to immobilize or retard Cu, Cr, and As species in soil/CCA-ash mixtures was studied. The amendments evaluated were agricultural lime (CaCO3/MgCO3), soil softener (CaSO4 · 2H2O), and iron sulfate (FeSO4). Results of this investigation show that native soil alone retards the mobility of As and Cr, amendments applied a...

Health-awareness and concern for the environment have resulted in voluntary removal of chromated copper arsenate (CCA) from wood preservatives in residential applications worldwide. Copper-based preservatives have been formulated as replacements, but these may not provide a permanent solution to all of the related problems, including copper contamination of aquatic environments and corrosion of fasteners. In this study, the copper retention (before and after the leaching process) of five softwood specimens vacuum-treated with alkaline copper quaternary (ACQ) and copper azole (CA) at three target retention levels was investigated by X-ray fluorescence studies. The metal corrosion and termite ( Coptotermes formosanus ) resistance of treated specimens were studied under laboratory conditions. Except for treated Japanese larch wood, the copper retention levels of the other wood specimens were able to meet the target copper retention values (use classes 2–4) in Chinese National Standard 3000. The copper leaching rates were 6.92–19.54% for ACQ-treated wood and 9.38–22.46% for CA-treated wood. The metal corrosion rates of iron nails due to corrosion tests (CNS 6717) were influenced significantly by the 1.2% ACQ and 1.2% CA treatments; whereas the metal corrosion rates of zinc-galvanized steel nails were less than 2 and could meet the tested standard. Even though the ACQ and CA treatments caused higher copper leaching rates from the treated specimens, they also increased termite mortalities and reduced the mass loss significantly after termite-resistance tests (JIS K 1571).

The disposal of wood waste treated with chromated copper arsenate (CCA) is a problem in many countries. We have proposed a novel chelating extraction technique for CCA-treated wood using bioxalate, a solution of oxalic acid containing sufficient sodium hydroxide to adjust the pH to 3.2, which is an effective way to obtain an extraction efficiency of 90% for chromium, copper, and arsenic. The purpose of the present study was to investigate the characteristics of bioxalate extraction of CCA-treated wood. Extractions of CCA-treated western hemlock chips with solutions of bioxalate, oxalic acid, and sodium hydroxide were carried out. The use of bioxalate was confirmed as the most effective extraction technique for chromium, copper and arsenic, with an efficiency of 90%. Extraction with simple oxalic acid was ineffective for copper (less than 40% extraction efficiency), but effective for chromium and arsenic, with 90% efficiency. Sodium hydroxide showed a similar tendency, being ineffective for chromium and copper (less than 20% extraction efficiency), but relatively effective for arsenic (around 70-80% efficiency). We also discovered an interesting phenomenon whereby the addition of sodium hydroxide to a simple oxalic acid solution during the oxalic acid extraction progress resulted in dramatically increased extraction efficiency for copper, chromium and arsenic, up to 90%. Although oxalic acid was ineffective for copper extraction, the addition of sodium hydroxide during the oxalic acid extraction process rendered it effective.

Several states have recently considered altering disposal requirements for chromated copper arsenate (CCA)-treated wood waste, particularly Florida, where CCA-treated wood waste is disposed in unlined construction and demolition (C&D) debris and Class III municipal solid waste (MSW) landfills. The primary concern is the potential for CCA-treated wood waste to elevate arsenic levels in groundwater downgradient of the disposal sites. To address this concern, we evaluated the impact of past disposal practices of these wastes in unlined Florida C&D and Class III landfills by conducting a statistical analysis of two sets of groundwater data compiled by the Florida Department of Environmental Protection (FDEP). The databases contain water quality data from C&D and Class III landfills in Florida covering 15 yr of record from February 1992 through February 2007 and together provide the most complete datasets to evaluate this issue. Comparative statistics of the different population groups in the databases showed that the arithmetic mean concentrations of total arsenic were in most cases higher in background wells than in wells downgradient of the landfills. The statistical analysis indicates that past disposal of CCA-treated wood in C&D and Class III landfills in Florida has not increased arsenic levels downgradient of the landfills. Policy decisions regarding the continued disposal of CCA-treated wood waste as a nonhazardous waste in unlined landfills must therefore be based on a scientifically sound assessment of potential future impacts. Quantitative predictions of future impacts are difficult and pose several scientific challenges. Therefore, future management decisions should be based on a more accurate and comprehensive risk analysis that assesses the risks and benefits of different alternatives and takes into account the natural attenuation capacity of soils and aquifer solids for arsenic and the practical limitations of managing this waste stream as a hazardous waste.

The segregation and disposal of chromated copper arsenate ( CCA )-treated wood waste when recycling building waste materials is a serious issue. We examined the contents of CCA preserved cedar timber by PIXE analysis. CCA preserved timber contained large amounts of these metals both on the surface and core of the wood. The ratio of chromium, copper and arsenic contained on the surface was 1:2:1, and in contrast, the ratio in the core was 1:1:2. In other words, the arsenic content was highest in the core. Moreover, the chemical form of arsenic in both parts of the wood was only inorganic arsenic; the same form of arsenic in preservative components known as carcinogenic substances. These findings mean that the complete separation of waste CCA preserved timber from construction and demolition wood is needed.

The objective of the present study was to evaluate the viability of reducing landfill requirements to satisfy EC Landfill Directive requirements by applying composting/bioremediation techniques to the construction and demolition (CD) industry waste stream at laboratory scale. The experimental study was carried out in nine test rigs to examine different wood mixtures; untreated timber, creosote treated timber and chromated copper arsenate (CCA) treated timber. Several experimental variables affecting the process were characterised and optimised. These include the best nitrogen additive and optimum moisture content required for composting. Poultry manure was found to be the best nitrogen additive. The optimum moisture content was decreased after the addition of poultry manure. The composting/bioremediation process was evaluated through monitoring the microbial activity, carbon dioxide emissions and toxicity examination of the composted product. A typical temperature profile suggested that untreated and CCA treated mix could be classified as hot composting whereas creosote treated mix could be classified as cold composting. The paper reports on the results obtained during this investigation.

This study examined the toxicity and accumulation of copper in the livers and kidneys of Long-Evans rats after a subacute exposure to copper dimethyldithiocarbamate (CDCC) wood preservative. CDDC was recently introduced as an alternative to chromated copper arsenate (CCA) preserved wood. Female rats (220-270 g) were treated with 0, 25, 50, or 75 mg/kg CDDC by oral gavage for 3 wk. Light microscopy revealed that higher doses of CDDC induced diffuse necrosis and a loss of sinusoids in the livers of Long-Evans rats with vacuolization in the highest dose. Rats treated with 25 mg/kg CDDC displayed a thickening of the basement membrane of Bowman's capsule and the mesangium. Exposure to higher CDDC concentrations (50 and 75 mg/kg) showed moderate to marked expansion of the mesangial matrix and glomerular necrosis with an overall loss of glomerular structure seen in the highest dose. The concentration of copper was significantly increased in the tissues of animals exposed to CDDC in a dose-dependent manner. Western blot analysis revealed the induction of the stress protein Hsp70 and the formation of 4-hydroxy-2-nonenal (4HNE) adducts in liver and renal tissues, indicating peroxidative damage. CDDC was shown to be toxic to the livers and kidneys, at all doses used, and this toxicity is related to peroxidative insult.

This research combined the use of selective extractions and X-ray spectroscopyto examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e., proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/ Cr(III) solid phase that formed upon the Fe(II) application (25-50%) and a recalcitrant phase (50-75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solid phases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.

Because of the potentially high metal concentrations found in soils immediately adjacent to chromated copper arsenate (CCA)-treated wood structures and utility poles, CCA-contaminated soil ingestion may be a significant exposure route to Cr, Cu, and As for children. Therefore, a strong need exists to provide data on oral bioavailability of these elements in field-collected CCA-contaminated soils. Recently, As bioaccessibility in CCA-contaminated soils was assessed but data for Cr and Cu are lacking. Therefore, the objectives of this study were (1) to assess the bioaccessibility of Cr and Cu in contaminated soils collected near in-service CCA-treated utility poles; and (2) to determine the influence of selected soil properties on their bioaccessibility. Cr and Cu bioaccessibilities (in vitro gastrointestinal method) were determined on surface soil samples collected immediately adjacent to 12 CCA-treated utility poles after 18 months of service. Bioaccessible Cr and Cu were also determined in three certifie...

Information on chromium (Cr) oxidation states is essential for the assessment of environmental and health risks associated with the overall life-cycle of chromated copper arsenate (CCA) treated wood products because of differences in toxicity between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium compounds. Hypothetical Cr(VI) fixation products were investigated in CCA type C treated sawdust of aspen and red pine during or following preservative fixation by extraction with Cr(VI)-specific extractants. Cr(VI) was found only in alkaline extracts of treated wood. A major source of Cr(VI) was method-induced oxidation of fixed Cr(III) during alkaline extraction, as confirmed by demonstrated oxidation of Cr(III) from CrCl3 treated wood. Oxidation of nontoxic and immobile Cr(III) to toxic and mobile Cr(VI) was facilitated by the presence of wood at pH8.5. Thermodynamic equilibrium between Cr(III) and Cr(VI) is affected by pH, temperature, rates of dissolution of CrIII) compounds, and oxygen availability. Results of this study recommend against alkaline extraction protocols for determination of Cr(VI) in treated wood. This Cr oxidation mechanism can act as a previously unrecognized route for generation of hazardous Cr(VI) if CCA treated wood is exposed to alkaline conditions during its production, use, or waste management.

In this study the weathering behavior of southern yellow pine (SYP) wood samples pretreated in different solutions has been examined using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and various types of physical characterization regarding material loss and discoloration. The treatment solutions include water as a control, a commercially available water repellent (WR) wood treating additive and polyethylene glycol (PEG) products including PEG PLUS™, PEG 8000 solutions and Compound 20M in varying concentrations. All contained the wood preservative chromated copper arsenate (CCA). One sample was treated with a CCA solution only. The treatments were carried out at 20 °C and 150 psig for 1/2 h after exposure to vacuum (28 mmHg) for 15 min. Simulated weathering was achieved in an Atlas 65-W Weather-Ometer for 2000 h with both light and dark periods and rain. The temperature ranged from 23 °C during the dark cycle to 35 °C during the light cycle. With weathering the XPS O/C ratios increase due to oxidation of the surface. Exposure to UV light results in bond breakage and reaction with oxygen in the presence of air to form organic functional groups such as , , C O and/or O–C–O. These oxidized products can protect the underlying wood from deterioration if they are insoluble in water and remain on the surface as a protective coating. If soluble, rain washes the compounds away and assists in the degradation. Correlated changes are observed in the XPS O/C ratios, the high-resolution XPS C 1s spectra, the SEM micrographs and physical measurements including thickness alteration, weight loss, and discoloration by yellowing or whitening of the weathered wood. The PEG treatments are effective in protecting wood with the 2% PEG PLUS treatment providing the best weathering behavior similar to that of the CCA treatment. The WR and water treatments yield the poorest weathering properties.

Substantial progress has been made in remediation of preservative treated waste wood by chemical extraction with several mineral and organic acids and biodegradation using bacteria and fungi in recent years. Non-conventional low-cost adsorbents are used to bind the metal ions in extremely stable complexes in heavy metal contaminated soils or polluted waters and thus to remediate such substrates. In this study, various adsorbents from industrial and agricultural processes were evaluated in removal of copper, chromium, and arsenic from chromated copper arsenate (CCA)- treated wood by using batch extracting experiments. Most adsorbents used in the study had the potential to remove copper ele- ment from CCA-treated wood, while chromium was the most resistant element against removal in most cases. In general, as amount of adsorbents in the extraction process and extraction duration increased, the percentage of elements removed increased. The adsorbents used in the study could be important in the remediation of wood treated with organic or water- borne wood preservatives containing copper since the use of the adsorbents is one key to unfix copper from treated wood treated.

We used the local lymph node assay to evaluate the abilities of chromated copper arsenate (CCA), a commonly used wood preservative, and its components to cause sensitizing reactions after their dilution in acetone-olive oil (AOO) and dimethyl sulfoxide (DMSO). After CBA/J mice were treated topically with 0.3 to 10% CCA, 0.3-3% chromium oxide, 0.3-3% arsenic oxide, or 0.3-3% copper oxide, their auricular lymph nodes (LN) were weighed and used in lymphocyte proliferation assays. In addition, total levels of chromium and arsenic in blood samples were measured. In all groups treated with CCA in AOO or DMSO, all parameters, including LN weight and lymphocyte proliferation, increased in a dose-dependent manner. The stimulation index (SI; the mean [3H]-TdR incorporation of the treatment group divided by that of the control group) showed a positive response (SI > 3) in all treatment groups; the EC3 values (estimated concentration to yield SI of 3) of CCA in AOO and DMSO were 1.86% and < 0.3%, respectively. In addition, we confirmed that the three components of CCA--chromium oxide, arsenic oxide and copper oxide--each individually exerted sensitizing ability. Mice treated with arsenic oxide in AOO or DMSO yielded nearly equal positive responses; however, the LLNA responses in mice treated with chromium oxide and copper oxide was much higher in the DMSO groups than in the AOO groups. The total chromium level in blood was higher in DMSO groups than AOO groups, whereas arsenic levels were comparable between the DMSO and AOO groups. Our findings suggest that CCA has sensitizing activity and that the type of solvent used can influence the results of sensitization assays evaluating metals.

This research aimed to evaluate the physical properties of OSB panels manufactured using Parica (Schizolobium amazonicum) wood species particles, treated with CCA (chromated copper arsenate) and CCB (chromated copper borate) preservatives, and castor oil based polyurethane resin. Three resin contents were evaluated: 8, 10 and 12%. Results showed that OSB panels manufactured with CCA-treated wood particles did not meet the minimum requirements stipulated by EN 300Code, while OSB containing CCB treated wood particles reached the properties values required for structural applications in dry conditions. Therefore, it was demonstrated the feasibility of using CCB-treated Parica wood and castor oil based polyurethane resin in OSB production.