Search

Outdoor building materials made of wood require preservatives containing chromated copper arsenate and other carcinogenic substances but still are subject to decay, hence they need to be replaced every few years. Wood-plastic composite (WPC) is an environmental-friendly composite of wood flour/fiber reinforced thermoplastic polymers (i.e., plastic). As WPC is made of plastic to evenly cover the wood flour, it has a lower moisture content than wood. In this study, maleic anhydride grafted polyolefin elastomers (POE-g-ma) and methyl methacrylate-butadiene-styrene copolymer (MBS) were used as impact modifiers to prepare WPCs from recycled polyethylene terephthalate (rPET) and recycled polyamide 6 (rPA6) blends (PET/PA6). The thermal properties of the WPCs with different mixing ratio polymer blends of rPET to rPA6 (E60/A40, E50/A50, and E40/A60) were investigated, as well as their mechanical properties after accelerated weathering. In addition, the creep behavior of the E40/A60 WPC under different environmental conditions was investigated. During the 10-h creep test, the POE-g-ma/WPC strain varied significantly more than MBS/WPC under environmental aging and higher loadings. The test results of impact and creep also show that the toughening effect of POE-g-ma/WPC was slightly better than that of MBS/WPC. In summary, the higher PET content resulted in lower flowability and a higher initial decomposition temperature, with the E60/A40 WPC having better anti-aged mechanical properties and more suitable for outdoor building applications.

Full-cost accounting techniques incorporate the environmental and societal burdens a product generates through its manufacture, use, and disposal into that product’s price. This research generates full-cost prices for functionally equivalent chromated copper arsenate (CCA) treated wood and galvanized steel guardrail posts by combining previously conducted life cycle inventory analyses results with secondary emission valuation data. Based on the analysis, both CCA-treated posts and galvanized steel posts have environmental damage costs associated with emissions generated through the product’s manufacturing, use, and disposal stages. After developing full-cost prices for product alternatives, CCA-treated wood guardrail posts were found to be a more economical and environmentally responsible alternative to galvanized steel. In addition to generating full-cost prices, this research uses Monte Carlo simulation to provide estimates of variability around CCA-treated wood and galvanized steel damage costs.

Aim: The use of copper-based preservatives such as chromated copper arsenate (CCA) and creosote to prolong the life of lumber present environmental concerns because they contain heavy metals and polycyclic aromatic hydrocarbons which are toxic to humans. The aim of this study was to investigate the effects of sewage sludge biosolid amendment on the distribution and mobility of chromium, copper and arsenic in chromated copper arsenate contaminated soils subjected to phytoremediation using maize (Zea mays L.). Place and Duration of the Study: Random composite soil samples from Kitetika wood factory, Wakiso, Uganda and sewage sludge biosolid from National Water and Sewerage Corporation plant in Bugolobi, Kampala, Uganda were collected and prepared. Maize grains were obtained from FICA Seeds Limited (Uganda). The pot experiments and analysis of samples were done at Mbarara University of Science and Technology (Mbarara) and Directorate of Government Analytical Laboratory, Kampala (Uganda), respectively. Methodology: The fresh CCA contaminated soils and sewage sludge biosolid were analyzed for physicochemical parameters and heavy metals (chromium, copper and arsenic). Sewage sludge biosolid was added to 1 kg of the contaminated soils at 5-25% (w/w) in 2 L plastic containers, watered and maintained at 25 ℃ for 14 days to stabilize. Controls were set up with unamended soils. Thereafter, maize was planted in the potted soils for 40 days. The concentrations of the trace metals in the soils were determined after 20 and 40 days of maize growth by atomic absorption spectroscopy. Results: The concentrations of chromium, copper and arsenic in fresh CCA contaminated soils were 365.8 ± 6.18 mg/kg, 109.72 ± 14.04 mg/kg and 28.22 ± 3.8 mg/kg, respectively. Basing on mobility factor, bioavailability of the trace metals followed the chemical sequence copper (8.9%) < chromium (17.1%) < arsenic (30.2%). Conclusion: The maize variety experimented could be used to phytoextract or phytostabilize the trace metals in the CCA contaminated soils without or with 5-25% amendment. Amendment with sewage sludge biosolid improved the phytoremediation potential of maize. Arsenic was the most mobile and bioavailable metal in CCA contaminated soils. Further studies should use other local maize varieties such as Longe series.

Widely used as wood preservatives for the last century, Pentachlorophenol (PCP) and chromated copper arsenate (CCA) have been shown to leach from treated surfaces and contaminate soil of wood storage sites. We performed a four-year field phytoremediation trial in southern Quebec (Canada) on a site contaminated with PCP and CCA with the following objectives: (1) assess the potential of willow, fescue, alfalfa and Indian mustard to tolerate and translocate CCA and PCP residues in their aerial tissues, (2) investigate the possibility of phytoextraction of dioxins and furans, and (3) test the effect of nitrogen fertilizer on phytoremediation performance. We showed that while nitrogen fertilization increased the chlorophyll content of plants, it did not result in a significantly greater plant biomass. We also showed that plants grown in the presence of PCP/CCA residues were able to translocate and concentrate trace elements in their aerial tissues, but also dioxins and furans (PCDD/F). This suggests that plants grown on sites polluted by PCP might contain dioxins and furans and should be treated as contaminated by these toxic chemicals. Finally, the reduction of soil contaminants at the end of the trial suggests that phytoremediation is a promising approach for decontaminating such sites.

Use of water-borne wood preservatives began in approximately the 1950s. Residential and commercial uses rapidly developed for products such as decking, fences, and other outdoor structures. Nearly all such products were treated by preservatives using arsenic as a major ingredient. The most common preservative was chromated copper arsenate (CCA). A smaller volume used ammoniacal copper zinc arsenate (ACZA). Preservative label changes made in 2003 limited uses of these arsenical treatments to industrial or agricultural type uses, such as poles, piles, ties, bridges, and fencing. Use volumes of preservative-treated wood continued to grow after the label change, but the types of preservatives used changed greatly. The amounts of water-borne treated wood reaching end-of-life and being disposed also continued to grow, reflecting the increasing inventory of volume in service. However, the volume of arsenical-treated wood being disposed peaked in approximately 2008 and is now only approximately one-quarter of that volume. Most of the arsenical-treated wood now being disposed consists of large, easily identified and separated pieces, such as round poles, piles, and fence posts and timbers, which can be easily managed separated from other wood construction and demolition (C & D) waste. Thus, managing C & D waste to limit arsenic contamination of potential products, such as mulch, will be much more practical than some have feared.

The effect of sewage sludge amendment (5-25% w/w) on the potential of maize (MM3 variety) to phytoextract trace metals from chromated copper arsenate (CCA) contaminated soils was investigated. The metal content of fresh soils, and soils, maize roots and shoots after 80 days of planting were determined by atomic absorption spectroscopy. The concentrations of chromium, copper and arsenic in fresh CCA soils were 365.8 ± 6.18, 109.72 ± 14.04 and 28.22 ± 3.8 mg/kg respectively. The MM3 maize variety could be used to phytoextract or phytostabilize the trace metals in the CCA contaminated soils without or with 5-25% sewage sludge amendment.

Bamboo is readily discolored by mold fungi, which greatly limits its applications. An effective antifungal agent, copper(II) chloride (CuCl2)-grafted silica gel, was prepared by a sol–gel process using tetraethoxysilane (TEOS)/3-aminopropyltriethoxysilane (APTES) mixtures. The elemental composition and the chemical combinations of homogeneous sol mixture (HSM) and bamboo were determined via Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM–EDS). The mold resistance of bamboo treated with HSM, alkaline copper quat (ACQ), chromated copper arsenate (CCA), and purified water was characterized by an indoor mold test. The micro-morphology of bamboo treated with HSM was investigated using scanning electron microscopy (SEM). HSM penetrated into the bamboo vessels, and formed xerogels, which was able to coordinate copper(II) cations. SEM–EDS investigations suggest that Si–O–Cu linkages may be formed through an exchange reaction between silanol groups and copper complexes. The bamboo samples treated with HSM showed highly efficient mold resistance due to a good penetration of HSM. Furthermore, no fungal hyphae were found in the structure of HSM-treated bamboo after a 5-week mold test. The copper complexes grafted to silica gel developed in this work provide an efficient antifungal agent for a wide range of potential applications in bamboo protection.

This study objective was to investigate the biological efficacy of a commercial dispersion of micronized copper azole (MCA) on plantation grown rubberwood. MCA is a formulation containing micronized copper carbonates and azole, an organic co-biocide. The impact of MCA pressure treatments with various concentrations of the active ingredients and the treatment durations on retentions, leaching rate, mechanical properties and biological performance against brown and white rots were evaluated. Biological performance of MCA treated rubberwood at minimum retention of 2.8 ± 0.3 kg/m3 was found to be comparable to that of chromated copper arsenate (CCA) treatment at 15.1 ± 2.3 kg/m3. Field tests are being conducted to confirm the laboratory findings.

The aim of this study was to determine the bioavailability of metals in field soils contaminated with chromated copper arsenate (CCA) mixtures. The uptake and elimination kinetics of chromium, copper, and arsenic were assessed in the earthworm Eisenia andrei exposed to soils from a gradient of CCA wood preservative contamination near Hartola, Finland. In soils contaminated with 1480–1590 mg Cr/kg dry soil, 642–791 mg Cu/kg dry soil, and 850–2810 mg Ag/kg dry soil, uptake and elimination kinetics patterns were similar for Cr and Cu. Both metals were rapidly taken up and rapidly excreted by Eisenia andrei with equilibrium reached within 1 day. The metalloid As, however, showed very slow uptake and elimination in the earthworms and body concentrations did not reach equilibrium within 21 days. Bioaccumulation factors (BAF) were low for Cu and Cr (

Construction and demolition (C&D) wood can be recycled as mulch for landscaping or cogeneration. Limitations to such recycling are dependent on metals concentrations in mulch (As, Cu, and Cr) from the inclusion of waterborne-preservative treated wood. The objective of this study was to evaluate the amount of waterborne-preservative treated wood (by wood volume and by mass of metal) that enters the C&D wood waste stream in the U.S. by utilizing a mass balance approach. A model was developed using wood treatment industry production statistics, estimated leaching rates of metal-based preservatives, and typical service lives of wood products. Outputs of the model indicate that the volumes of waterborne preservative treated wood disposed of may exceed 16 million m3 per year by 2030. The peak yearly metal mass disposed of corresponded to 18,400 metric tons for arsenic and 24,500 tons of chromium in 2013. Given the current trends in production, the mass of copper disposed of will increase to 20,900 tons by 2030. In order to meet regulatory guidelines regarding metals in recycled C&D wood, waterborne-preservative treated wood must be separated and removed. This separation mitigates environmental contamination from wood preservatives such as chromated copper arsenate (CCA).

Chromated copper arsenates (CCA) have been extensively used as wood impregnation agents in Europe and North America. Today, CCA contaminated sites remain abundant and pose environmental risks that need to be properly managed. Using a TRIAD approach that combined chemical, ecotoxicological and ecological assessment of soil quality, we investigated the abilities of biochar and zero-valent iron (ZVI) to remediate CCA contaminated soil in a microcosm experiment. Soil samples from a highly contaminated CCA site (1364, 1662 and 540 μg g−1 of As, Cu and Cr, respectively) were treated with two different biochars (fine and coarse particle size; 1% w w−1) and ZVI (5% w w−1), both as sole and as combined treatments, and incubated for 56 days at 15 °C. In general, bioavailable As (Asbio) and Cu (Cubio) determined by whole-cell bacterial bioreporters corresponded well to water-extractable As and Cu (Aswater and Cuwater). However, in biochar treatments, only Cubio and not Cuwater was significantly reduced. In contrast, under ZVI treatments only Cuwater and not Cubio was reduced, demonstrating the value of complementing analytical with bacterial bioreporter measurements to infer bioavailability of elements to soil microorganisms. The combined fine particle size biochar and ZVI treatment effectively reduced water extractable concentrations of Cr, Cu, and As on site by 45%, 45% and 43% respectively, and led to the highest ecological recovery of the soil bacterial community, as measured using the [3H]leucine incorporation technique. We conclude that the combined application of biochar and ZVI as soil amendments holds promise for in-situ stabilization of CCA contaminated sites.

The aim of this study was to evaluate the efficacy of biological and chemical remediation of chromated copper arsenate (CCA) treated Corymbia citriodora poles, removed from service after 30 years. The presence of arsenic (As), chromium (Cr) and copper (Cu) was quantified by inductively coupled plasma optical emission spectrometry (ICP–OES). Twelve species of decay fungi were used for the biological remediation assay. For chemical remediation oxalic, citric, maleic and ethylenediamine tetraacetic (EDTA) acids were used for 24 and 48 h. In biological remediation, copper-tolerant brown-rot fungi, Wolfiporia cocos, Antrodia xantha and Fibroporia radiculosa, performed the best results, with the highest removals for As (59–85 %) and Cr (38–61 %). Cu was the most easily extracted, with removals above 60 % among the tested fungi, with the best results (90–98 %) for F. radiculosa, Coniophora puteana, Antrodia vaillantii and Postia placenta. In chemical remediation, the extraction time of 48 h was the most effective, and oxalic acid generally reached the highest removals. The EDTA + oxalic acid combination reached the highest value for Cu extraction (98 %).

Wood is a common construction material used in most environments. However, its sensibility to abiotic agents, in particular those that affect the dimensional stability, limits the durability of the material and decreases its properties. In this work, the efficiency of a paraffin-emulsion-based product as a water repellent, combined with the selection of Eucalyptus grandis clones with a low cracking index, was tested for its use in utility poles in order to improve the woods dimensional stability. Four selected Eucalyptus grandis clones were treated with the product mixed with Chromated Copper Arsenate - the most commonly used wood protector - in a single stage by the Bethell method at two retention levels. The dimensional stability of the treated samples was studied through the determination of anti-shrink efficiency. Test samples were also exposed to accelerated weathering processes for 200 h, and later analyzed by SEM microscopy. Results showed a significant improvement in the dimensional stability of treated wood when compared to samples without the water repellent, with variable efficacy depending on the clone used. Despite the weathering process slightly affected the appearance of the wood surface, the product is suitable for exterior use.

Micronized Cu (μ-Cu) is used as a wood preservative, replacing toxic chromated copper arsenate (CCA). Micronized Cu is malachite [Cu(2)CO(3)(OH)(2)] that has been milled to micron/submicron particles, with many particle diameters less than 100 nm, mixed with biocides and then used to treat wood. In addition to concerns about the fate of the Cu from μ-Cu, there is interest in the fate of the nano-Cu (n-Cu) constituents. We examined movement of Cu from μ-Cu treated-wood after placing treated-wood stakes into model wetland ecosystems. Release of Cu into surface and subsurface water was monitored. Surface water Cu reached maximum levels 3 days after stake installation and remained elevated if the systems remained inundated. Subsurface water Cu levels were 10% of surface water levels at day 3 and increased gradually thereafter. Sequential filtering indicated that a large portion of the Cu in solution was associating with soluble organics, but there was no evidence for n-Cu in solution. After 4 months, Cu in thin-sections of treated-wood and adjacent soil were characterized with micro X-ray absorption fine structure spectroscopy (μ-XAFS). Localization and speciation of Cu in the wood and adjacent soil using μ-XAFS clearly indicated that Cu concentrations decreased over time in the treated-wood and increased in the adjacent soil. However, n-Cu from the treated-wood was not found in the adjacent soil or plant roots. The results of this study indicate that Cu in the μ-Cu treated-wood dissolves and migrates into adjacent soil and waters primarily in ionic form (i.e., Cu(2+)) and not as nano-sized Cu particles. A reduced form of Cu (Cu(2)S) was identified in deep soil proximal to the treated-wood, indicating strong reducing conditions. The formation of the insoluble Cu(2)S effectively removes some portion of dissolved Cu from solution, reducing movement of Cu(2+) to the water column and diminishing exposure.

Wood is a renewable material considered eco-friendly and used for various purposes. While wood treated with chromated copper arsenate (CCA) does not deteriorate, its final disposal may entail risks due to the concentration and toxicity of the components. The removal of CCA from wood can be achieved in different ways. This study focuses on the reduction of the concentrations of Cu, Cr, and As chemical species by the electro-removal technique, aiming to obtain biomass with low deleterious potential that would allow multiple uses or safe disposal in landfills. The analytical results showed reductions of 79.5, 87.4, and 81.3% in the mean concentrations of Cu, Cr, and As, respectively. It is worth mentioning the occurrence of the fungus Xylaria sp. after treatment 6 (60 min, 5 g, and 25 V), further suggesting that the method was effective. Samples of these fungi were identified from isolates by culture in medium, DNA extraction, and sequencing of the Internal Transcribed Spacer (ITS) region. RESUMO A madeira é um material renovável, considerado ecologicamente correto e utilizado para diversos fins. Embora a madeira tratada com arseniato de cobre cromado (CCA) não se deteriore facilmente, seu descarte final pode acarretar riscos devido à concentração e toxicidade dos componentes. A remoção do CCA da madeira pode ser realizada de diferentes maneiras. Este estudo teve como foco a redução das concentrações de espécies químicas Cu, Cr e As pela técnica de eletro-remoção, visando obter uma biomassa com baixo potencial deletério que permitiria múltiplos usos ou disposição final segura em aterros sanitários. Os resultados analíticos mostraram reduções de 79,5; 87,4 e 81,3% nas concentrações médias de Cu, Cr e As, respectivamente. Vale ressaltar a ocorrência do fungo Xylaria sp. após o tratamento 6 (60 min, 5 g e 25 V), sugerindo ainda que o método foi eficaz. Amostras desses fungos foram identificadas dos isolados por meio de cultura em meio, extração de DNA e sequenciamento da região do espaçador transcrito interno (ITS).

Pentachlorophenol and chromated copper arsenate (CCA) have been used worldwide as wood preservatives, but these compounds can toxify ecosystems when they leach into the soil and water. This study aimed to evaluate the capacity of four treatment wetland macrophytes, Phalaris arundinacea, Typha angustifolia, and two subspecies of Phragmites australis, to tolerate and treat leachates containing wood preservatives. The experiment was conducted using 96 plant pots in 12 tanks filled with three leachate concentrations compared to uncontaminated water. Biomass production and bioaccumulation were measured after 35 and 70 days of exposure. There were no significant effects of leachate contamination concentration on plant biomass for any species. No contaminants were detected in aboveground parts of the macrophytes, precluding their use for phytoextraction within the tested contamination levels. However, all species accumulated As and chlorinated phenols in belowground parts, and this accumulation was more prevalent under a more concentrated leachate. Up to 0.5 mg pentachlorophenol/kg (from 81 &micro, g/L in the leachate) and 50 mg As/kg (from 330 &micro, g/L in the leachate) were accumulated in the belowground biomass. Given their high productivity and tolerance to the contaminants, the tested macrophytes showed phytostabilization potential and could enhance the degradation of phenols from leachates contaminated with wood preservatives in treatment wetlands.

The remediation of wood preservative–contaminated sites is an important issue due to the carcinogenic nature of some contaminants derived from wood preservatives (e.g., Cr+6, arsenate, and pentachlorophenol). This study evaluated the effects of fertilizer application on remediation potential of co-plantings of Salix interior Rowlee. (Salix) and Festuca arundinacea Schreb. (Festuca) in a wood preservative–spiked technosol while considering the potential contaminant and nutrient leaching. Two levels of nitrogen (N) and phosphorus (P) fertilizers, NaNO3 and NaH2PO4 (25 and 75 mg L−1), were applied to achieve three N:P ratios, i.e., 3:1 (75:25), 1:3 (25:75), and 1:1 (25:25), that were compared with a control treatment (0:0 N:P) in a mesocosm experiment. Roots of the plant supplied with 1:1 and 1:3 N:P had more than double arsenic (As) and copper (Cu) amounts (i.e., biomass × concentration) compared to the control ones. Highest As and Cu amounts in shoots were found for Salix stems and Festuca leaves in the 1:3 and 1:1 N:P treatments, respectively. Arsenic and P leaching was high in mesocosms supplied with 1:3 N:P. Contamination and nutrient leaching in the 1:1 N:P treatment did not differ from the control, except for Cu. In conclusion, 1:1 N:P treatment yielded the best results in terms of metal(loid) uptake and contaminant and nutrient leaching. In 1:1 N:P treatment, the maximum values of percent As, Cr, and Cu in Salix and Festuca aboveground were 0.18%, 0.024%, and 1.20% and 0.89%, 0.08%, and 1.78%, respectively.

This paper reports the effect of water vapour on particulate matter (PM) during the separate combustion of in situ volatiles and char generated from chromated-copper-arsenate-treated (CCAT) wood at 1300 °C. Combustion of in situ volatiles produces only PM with aerodynamic diameter

The genera Eucalyptus and Corymbia are widely used in Brazil. Although they present remarkable applicability, they manifest substantial end-splitting and surface checks, which allows wood decay organisms to penetrate the wood. Thereby, the resistance of Eucalyptus grandis x Eucalyptus urophylla (EU) and Corymbia citriodora (CT) treated with chromated copper arsenate type-C (CCA-C) against fungi decay was evaluated. Seventy-two fence posts were assessed; for each species, there were 18 posts treated with CCA-C and 18 non-treated posts. The posts were 2.20 m long and classified into three classes of diameter. The 2% active ingredient was used with a vacuum-pressure cycle. On each fence, disks measuring 2.0 cm thick were cut at the outcrop zone. Two sets of depths were analyzed: the edge at 0 cm to 1.5 cm as well as the inner part at 1.5 cm to 3.0 cm. The samples were subjected to Postia placenta, Gloeophyllum trabeum, and Trametes versicolor attack. The treatment was effective against all fungi, but for CT, the diameter range of 8 cm to 12 cm was optimal. The treated wood from EU samples reached the lowest weight loss for all fungi. Heartwood-sapwood ratio played a major role. By comparing the non-treated woods, EU yielded the highest mass loss.

Large volumes of chromated copper arsenate (CCA)-treated wood are disposed of in lined and un-lined landfills across the world. Studies regarding the disposal and reuse of CCA-treated timber date back to the 1980s. This paper provides a comprehensive overview of the research undertaken regarding reconstituted chromated copper arsenate-treated timber products, and considers the relevant health issues and disposal techniques, such as incineration and thermochemical conversion, as well as long-term solutions for the managing of chromated copper arsenate-treated-waste wood. The results from reviewing the literature regarding reconstituted timber products consisting of CC-treated timber such as particle board, cement-bonded particle board, flake board, remediated wood composites, wood-plastic composites, and wood-cement composites revealed that products such as particle board, wood-plastic composites and flake board composed of CCA-treated timber show considerable promise. Further research is required to determine the optimum percentage of CCA-treated timber in wood-plastic composites to minimize leaching while attaining suitable physical and mechanical performance, and to evaluate the durability of reconstituted chromated copper arsenate timber products via severe accelerated aging tests. Several CCA-waste wood disposal methods were investigated in the form of extraction and destruction techniques including thermochemical conversion (pyrolysis, gasification), incineration, co-incineration and combustion. Such management techniques demonstrate promising, feasible, future solutions providing the ability to trap arsenic gas, recover metals, and create secondary energy forms. However, more research is required, especially regarding resultant arsenic compounds and their volatile behaviours. Industries that create and sell chromated copper arsenate-treated wood products are encouraged to follow the United States Environmental Protection Agency leachate testing procedures (Methods 1314 and 1315, published in 2013), since these methods are more accurate at evaluating the leaching behaviour during their lifetime, and various disposal scenarios that reflect differing pH values and liquid to solid ratios.

A pot experiment was conducted to investigate the heavy metal accumulation in maize (Zea mays L.) plant grown in chromated copper arsenate (CCA) soil amended with treated composted sewage biosolid. The initial concentrations of chromium, copper, arsenate in the CCA soil and sewage biosolid were determined by atomic absorption spectrophotometer. These were found to be, in CCA soil: 365.8 ± 6.18, 109.22 ± 14.04, 28.22 ± 3.8 and in sewage biosolid: 35 ± 1.06, 1.0 ± 0.02, 0 mg·kg-1 respectively. The concentration of Cr, Cu and As determined in both the roots and shoots generally decreased with increase in percentage amendment concentration and number of days (20 and 40 days after planting). At 20 days, the total metal concentration ranges in roots were As (5.54 ± 0.03 - 6.69 ± 1.14), Cr (9.59 ± 0.02 - 13.22 ± 0.03), Cu (2.28 ± 0.06 - 4.53 ± 0.37) mg·kg-1 while at 40 days the values were As (5.60 ± 0.19 - 6.08 ± 0.01), Cr (9.47 ± 0.04 - 10.95 ± 0.09), Cu (3.94 ± 0.19 - 4.64 ± 0.07) mg·kg-1. For the shoot system, the concentrations of the metals at 20 days were As (5.28 ± 0.03 - 5.90 ± 0.13), Cr (9.30 ± 0.05 - 10.07 ± 0.06), Cu (3.64 ± 0.12 - 4.72 ± 0.15) mg/kg while at 40 days the values obtained were As (5.28 ± 0.03 - 5.9 ± 0.13), Cr (9.69 ± 0.14 - 10.07 ± 0.03), Cu (2.94 ± 0.72 - 4.53 ± 0.03) mg·kg-1. The roots accumulated the three heavy metals more than the shoot system at all treatments used. Concentration of arsenic, chromium and copper in the plants decreased with increasing percentage amendments. The results suggest relatively low bioavailability of the three metals in CCA soil treated with high percentages of sewage biosolid as an amendment.

The present study investigates the possible use and effectiveness of starch-stabilized Fe/Cu nanoparticles for in situ immobilization of arsenic in contaminated soils. For this purpose, 0.04 wt.% starch-stabilized Fe/Cu nanoparticles were synthesized and tested through batch and column tests for the immobilization of arsenic in a loamy soil contaminated by chromated copper arsenate (CCA). When the CCA-contaminated loamy soil was treated with 0.4 g/L of starch-stabilized Fe/Cu nanoparticles (0.04 wt.%) at a soil-to-liquid ratio of 0.1, water-leachable arsenic was reduced by 92% and the toxicity characteristic leaching procedure (TCLP) leachability was reduced by 98%. Column elution experiments showed that through application of starch-stabilized Fe/Cu nanoparticles to CCA-contaminated soil, nearly all water-soluble arsenic was transferred to the nanoparticle phase. The TCLP leachability of arsenic remaining in the soil column was reduced by 70% due to the immobilization of arsenic by nanoparticles. In addition to an extremely high arsenic sorption capacity, starch-stabilized Fe/Cu nanoparticles exhibited excellent mobility in the soil environment. Both the high sorption capacity and the excellent mobility in the soil environment suggest potential for application of these nanoparticles to the contaminated soil for potential in situ arsenic immobilization.

Micronized copper azole (MCA) and micronized copper quaternary (MCQ) are the latest wood preservatives to replace the liquid alkaline copper and chromated copper arsenate preservatives due to concerns over the toxicity or lack of effectiveness of the earlier formulations. Today, the use of MCA has become abundant in the wood preservative industry with approximately 38millionlbs of copper carbonate being used to treat lumber each year. Despite this widespread usage, little information is available on the bioaccessibility of this preservative upon gastrointestinal exposure. Using a simulated hand-to-mouth/gastric system exposure study we investigated several types of commercially available copper-treated lumber products as-purchased and after exposure to outdoor weathering conditions. Soluble and particulate fractions of copper were measured after transfer to and release from surface wipes passed along copper-treated lumber and exposed to synthetic stomach fluid (SSF, pH1.5) or deionized (DI) water. Wipes passed along new boards contained greater amounts of copper than wipes from weathered boards. The total copper recovered from the wipes after microwave extraction varied among the different wood types. For all wood types the copper released into SSF was more soluble than what was soluble in DI water. The data suggest that copper from treated wood is highly bioaccessible in SSF regardless of wood type and weathering condition.

DOI: 10.7764/RDLC.16.2.307 Building wood frame houses is viewed as an excellent alternative to meet the growing demand for housing in Mexico. The aim was to design a pinewood house construction project, based on the stud structural system, to show how to proceed when building a particular housing model. The methodology is based on RCDF-2004, NTCRCDF-2004, ONNCCE S.C. Mexican standards and construction manuals. The blueprints, area and volume were derived using the AutoCAD 2010 program. Pinewood at MC≤18%, preserved with CCA (chromated copper arsenate) salts and graded with the "Class A" industrial rule was considered. Studs were placed every 24" and plywood boards were used as bracing. As a result, a one-story dwelling with a gable roof and 74 m 2 of living space was designed; the construction sequence, from the foundation (slab, chain and concrete footings) to the application of finishes and coverings (mortar and asphalt shingles), was performed. It is concluded that it is possible to properly design a wood frame house by following the recommendations and technical specifications in regulations, standards and manuals, thereby making it a practical alternative in housing construction.

The disposal of eucalyptus poles used in the electricity network distribution is considered a potential contamination to the environment due to the chromated copper arsenate (CCA) used as a wood preservative. The thermochemical process can be an alternative to this toxic waste disposal. In this work, the slow pyrolysis of CCA-treated wood followed by the production and application of activated carbon was proposed. Metal retention (ICP-OES), concentration of non-condensable gases produced in the pyrolysis process (via GC), as well as the capacity of activated carbon on CO 2 adsorption (via TGA) were investigated. The highest formation rate of non-condensable gases was observed at 500 °C, while the maximum H 2 concentration was at 700 °C. The char obtained in the pyrolysis was chemically treated with H 3 PO 4 and activated in CO 2 flow. The pore size distribution of activated carbons showed pore sizes lower than 1 nm. The activated carbons showed a CO 2 adsorption capacity of 70–83 mg/g. The presence of chromium and copper may have influenced the CO 2 adsorption. The fast adsorption and desorption showed by the activated carbon produced from CCA-treated wood is interesting to systems that operate in short-time cycles, as pressure swing adsorption (PSA). The reuse of CCA-treated wood for activated carbon production and its application in the CO 2 adsorption could be a solution to minimize the environmental damage caused by this waste.

Plywood can be used in the furniture industry and in civil construction due to its structural strength. However, for long useful life in construction, especially in tropical countries, it needs to undergo treatments against xylophagous organisms. The most common preservative treatment is the chemical chromated copper arsenate (CCA); there are alternatives, such as heat treatment, that do not use chemicals. The objective of this work was to evaluate the mechanical resistance of CCA and heat-treated plywood prepared at three different temperatures (160 °C, 180 °C, and 200 °C). Pinus taeda plywood with seven veneers and phenol-formaldehyde adhesive was produced and subjected to the preservative treatments. The results showed that the CCA treatment reduced the mechanical strength of the panels, while the heat treatment did not. Heat treatment also decreased panel hygroscopicity, indicating a better dimensional stability.

Arsenicals in agriculture: Beginning in the 1970s, the use of arsenic compounds, such as for wood preservatives, began to grow. By 1980, in the USA, 70 % of arsenic had been consumed for production of wood preservatives. This practice was later stopped, due to the US Environmental Protection Agency (EPA) ban of the arsenic-and chromium-based wood preservative chromated copper arsenate. In the past, arsenical herbicides containing cacodylic acid as an active ingredient have been used extensively in the USA from golf courses to cotton fields, drying out the plants before harvesting. The original commercial form of Agent Blue was among ten toxic insecticides, fungicides and herbicides partially deregulated by the US Environmental Protection Agency (EPA) in February 2004, and specific limits on toxic residues in meat, milk, poultry, and eggs were removed. Today, however, they are not used as weed-killers anymore, with one exception of monosodium methanearsonate (MSMA), a broadleaf weed herbicide for use on cotton. Severe poisonings from cacodylic acid caused headache, dizziness, vomiting, profuse and watery diarrhea, followed by dehydration, gradual fall in blood pressure, stupor, convulsions, general paralysis and possible risk of death within 3–14 days. The relatively frequent use of arsenic and its compounds, in both industry and agriculture, points to a wide spectrum of opportunities for human exposure; this exposure can be via inhalation of airborne arsenic, contaminated drinking water, beverages, or from food and drugs. Today, acute organic arsenical poisonings are mostly accidental. Considerable concern has developed surrounding its delayed effects, for its genotoxic and carcinogenic potential, which has been demonstrated in epidemiological studies and subsequent animal experiments. The Conclusion is that there is substantial epidemiological evidence for an excessive risk, mostly for skin and lung cancer, among humans exposed to organic arsenicals in occupational and environmental settings. Furthermore, the genotoxic and carcinogenic effects have only been observed at relatively high exposure rates. Current epidemiological and experimental studies are trying to elucidate the mechanism of this action, pointing to the question of whether arsenic is actually the true genotoxic or rather an epigenetic carcinogen. Due to the complexity of its effects both options remain plausible. Its interactions with other toxic substances still represent another important field of interest.

Industrial wastewater pollution has become more grievous in the third world countries, where treatment and administration of industrial effluents are not being properly handled. About 80% of wastewater having arsenic (As) contamination are due to impurities in pesticides, chromated copper arsenate (CCA) wood preservatives, municipal solid waste incineration; leather industry; and consumption in the industry. Arsenic is a toxic metalloid, which is considered as a severe menace to the life of plants, animals and humans. Some As species such as As(III) and As(V) cause harmful effects on plants and animals. In order to treat As in industrial wastewater, various conventional methods are being employed. However, these methods face limitations in form of missing technical expertise and low effectiveness. Recently, microbial As remediation of industrial water has been evolved as a promising technology due to its public acceptance and cost effectiveness. The current review, for the first time, comprehensively summarizes the role of microbial remediation of As in industrial wastewater. In contrast to phytoremediation, the goal of using microbes is that dissolved arsenic species are converted microbially to arsine gas which is released into the atmosphere at non-toxic levels (dilution effect). In contrast to phytoremediation where arsenic is accumulated in plant material (waste production), this will not produce any solid or liquid waste - and this is just a key benefit of the microbial approach as the management of solid/liquid arsenic rich waste is a global concern and economic burden; however, it was so far only tested on laboratory scale with exception of biofilms that have been tested on pilot scale. Our review also indicated the huge undervalued potential and environmental friendly solution of microbial remediation of As contaminated industrial wastewater without solid/liquid waste production as conventional technologies do.

The performance and removal mechanisms of a hybrid constructed wetland (HCW) followed by a willow planted filter (WPF) were evaluated for the treatment of a leachate contaminated by wood pole preservatives (pentachlorophenol (PCP) and chromated copper arsenate) to reach the storm sewer discharge limits. The HCW aimed to dechlorinate the PCP and polychlorodibenzo-p-dioxins/polychlorodibenzofuran (PCDD/F) and to remove metals by adsorption and precipitation. The HCW was efficient in removing PCP (>98.6%), oil, arsenic (99.4%), chromium (>99.2%), copper (>99.6%%) and iron (29%) to under their discharge limits, but it was unable to reach those of Mn and PCDD/F, with residual concentrations of 0.11 mg Mn/L and 0.32 pg TEQ/L. Iron and manganese could be removed but were subsequently released by the HCW due to low redox conditions. No dechlorination of PCDD/F was observed since its chlorination profile remained the same in the different sections of the HCW. Adsorption was the most probable removal mechanism of PCDD/F. The WPF was able to remove some residual contamination, but it released Mn at a gradually decreasing rate. Total evapotranspiration of the leachate by a larger fertilized WPF and the construction of an underground retention basin are proposed to prevent any discharge of PCDD/F traces in the environment.

The paper discusses the potential of different waste biomaterials for biosorption. Waste biomaterials after citric acid fermentation and chitosan extraction using Aspergillus niger were evaluated for biosorption of toxic metals (Cu, Cr and As) from leachates of chromated copper arsenate woods. The different waste BMs, such as fungal biomass (living and dead), alkali insoluble material and acid and alkali insoluble material were used in this study. The effect of different parameters, such as biosorbent concentration, metal concentration and contact time were investigated. The fitness of biosorption data for Freundlich and Langmuir adsorption models was investigated through batch adsorption technique. Among the adsorption isotherm tested, Langmuir isotherm gave the best fit with correlation coefficients (R2) value ranging from 0.89 to 0.97; 0.96–0.99 and 0.76–0.95 for As, Cr and Cu, respectively using solid state fermented biomass. Similarly, the significant removal of metals (>60% in leachate 2) from waste CCA wood leachate was achieved with the different BMs. Therefore, this study demonstrates the potential of CA fermentation derived waste BMs for biosorption of toxic metals from waste waters.

Chromated copper arsenate (CCA) mixtures were used in the past for wood preservation, leading to large scale soil contamination. This study aimed at contributing to the risk assessment of CCA-contaminated soils by assessing the toxicity of binary mixtures of copper, chromium and arsenic to the earthworm Eisenia andrei in OECD artificial soil. Mixture effects were related to reference models of Concentration Addition (CA) and Independent Action (IA) using the MIXTOX model, with effects being related to total and available (H2O and 0.01 M CaCl2 extractable) concentrations in the soil. Since only in mixtures with arsenic dose-related mortality occurred (LC50 92.5 mg/kg dry soil), it was not possible to analyze the mixture effects on earthworm survival with the MIXTOX model. EC50s for effects of Cu, Cr and As on earthworm reproduction, based on total soil concentrations, were 154, 449 and 9.1 mg/kg dry soil, respectively. Effects of mixtures were mainly antagonistic when related to the CA model but additive related to the IA model. This was the case when mixture effects were based on total and H2O-extractable concentrations; when based on CaCl2-extractable concentrations effects mainly were additive related to the CA model except for the Cr–As mixture which acted antagonistically. These results suggest that the CCA components do interact leading to a reduced toxicity when present in a mixture.

The above-ground performance of decking treated with two alternative copper-based preservative for-mulations is being evaluated at a test site near Madison, Wisconsin, USA. Southern pine sapwood lumber specimens (38 mm by 140 mm by 910 mm) were pressure treated with 0,93 %, 1,40 % or 2,34 % (oxide basis) actives concentrations of a boron-copper formulation (BC) composed of 7,2 % copper hydroxide and 92,8 % sodium tetraborate decahydrate. Similar specimens were pressure-treated with 0,66 % or 1,32 % actives concentrations of a copper-zinc formulation (CZDP) composed of 18 % copper (CuO basis), 12 % zinc (ZnO basis), 14 % dimethylcocoamine and 56 % propanoic acid. In both cases untreated specimens and specimens treated with a 1% concentration of chromated copper arsenate Type C (CCA-C) were included for comparison. The specimens were installed on racks approximately 760 mm above the ground and periodically evaluated for extent of fungal decay and surface microbial growth. After 18 years in test specimens treated with the lowest solution concentration of BC (0,93 %) suffered substantial degradation and all but three replicates have failed. Obvious decay has not yet been detected in specimens treated to the highest BC concentration (2,34 %), but decay is suspected in one of these specimens. Decking specimens treated with CZDP exhibited no evidence of decay until year 17 when a fruiting body was observed on one specimen treated with a 0,66 % solution concentration. There has been no evidence of decay in specimens treated with 1,32 % CZDP or in either set of specimens treated with 1 % CCA-C. Both BC and CZDP-treated specimens were at least as effective as 1 % CCA-C in minimizing noticeable surface microbial growth. These decking studies confirm that relatively low copper concentrations can provide substantial protection for decking exposed in a moderate climate, and that the CZDP formulation is potentially more effective than the BC formulation. However, caution is warranted in extrapolating these findings to more severe climates and to construction designs that are more likely to trap moisture

Concurrent occurrence of chromium (Cr), copper (Cu) and arsenic (As) from chromated copper arsenate (CCA) wood preservative in aquatic ecosystems demands that their joint-actions in eliciting toxic effects be assessed for adequate understanding of the health risk they may pose to biota. Clarias gariepinus was exposed to As2O3 , CrO3 and CuO and their composite mixtures (1:1 and 1:1:1) at various concentrations (0 – 600 mg/L) for 96-h to determine the acute toxicity using OECD (1992) protocol. C. gariepinus was then exposed to sub-lethal concentrations corresponding to 6.25, 12.5, 25.0, 50.0 and 100% of the 96-h LC50 for 7 days to assess the cytogenotoxic effects using piscine micronucleus (MN) test. The 96-h LC50 showed that the metals/metalloid demonstrated differential interactions in a concentration dependent pattern. The 96-h LC50 showed that Cr was the most toxic while Cu and As:Cu were indeterminate (Cr > Cr:Cu > As:Cr > As > As:Cr:Cu > Cu = As:Cu indeterminate). Isobologram and synergistic ratio (SR) models predicted antagonistic interaction between Cu:Cr and As:Cr and synergism between As:Cu in the causation of morbidity and mortality of C. gariepinus. Interaction factor model predicted antagonism as common interactive mechanism among the metal/metalloid mixtures in the induction of MN and abnormal nuclear erythrocytes in C. gariepinus. Predicted interactions among the three metals/ metalloid were largely antagonism and synergism towards the induction of acute toxicity and cytogenotoxicity. The models employed herein may be useful in establishing environmental safe limits for mixtures of metals/metalloids against the induction of acute toxicity and DNA damage in lower aquatic vertebrates.

Four types of pellets and three agro-fuels were chemically characterised and burned in a pellet stove. To assess the influence of the material composing the firebox and the combustion efficiency of distinct biomass heating devices in the composition of the bottom ashes, three of the pellets were also burned in a conventional woodstove and in a fireplace. Ashes were analysed for their C, H and N contents by an elemental analyser, whilst major and trace elements were quantified by inductively coupled plasma atomic-emission spectrometry and inductively coupled plasma mass spectrometry, respectively. The mineralogy of ashes was determined by X-ray powder diffraction. The European standard test was applied to samples to determine the leaching potential of major, minor and trace elements. The contents of major and trace elements in the different types of biomass presented enormous variations, which are reflected in dissimilar mineralogical and chemical compositions of the respective ashes. The leachable potential of several elements of environmental concern present in oxy-anionic form at the alkaline pH of biomass ashes were generally high in all samples. Concentrations of some elements in the leachates were in the range of values with classification of “hazardous materials” by the European legislation in what respects the acceptance of these wastes at landfills. Pellets made up of wood wastes and containing preservatives (chromated copper arsenate and ammoniacal copper arsenate) are of concern. Due to lower combustion efficiencies, the leachable potential for most of the trace elements in ashes from the woodstove, and especially from the fireplace, was lower than that of the pellet stove. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature., This study was funded by the European Commission through the project “AIRUSE - Testing and Development of Air Quality Mitigation Measures in Southern Europe” (LIFE11 ENV/ES/000584). Estela Vicente received a fellowship (SFRH/BD/117993/2016) from the Portuguese Foundation for Science and Technology (FCT). This study was also financially supported by CESAM (UID/AMB/50017 - POCI-01-0145-FEDER-007638), FCT/MEC through national funds, FEDER, within the PT2020 Partnership Agreement and Compete 2020. The Generalitat de Catalunya (AGAUR 2017 SGR41) also supported this study.

Copper chrome arsenate (CCA) water-borne solution used to be widely used to make timber highly resistant to pests and fungi, in particular, wood products designed for outdoor use. Nowadays, CCA is a restricted chemical product in most countries, since potential environmental and health risks were reported due to dermal contact with CCA residues from treated structures and the surrounding soil, as well as the contamination of soils. However, large quantities of CCA-treated timber are still in use in framings, outdoor playground equipment, landscaping, building poles, jetty piles, and fencing structures around the world, thus CCA remains a source of pollutants to the environment and of increasing toxic metal/metalloid exposure (mainly in children). International efforts have been dedicated to the treatment of materials impregnated with CCA, however not only does some reuse of CCA-treated timber still occur, but also existing structures are leaking the toxic compounds into the environment, with impacts on the environment and animal and human health. This study highlights CCA mechanisms and the documented consequences in vivo of its exposure, as well as the adverse environmental and health impacts.

The importance of a circular economy is today widely accepted and advocated, but among the challenges in achieving this, we find difficulties in the implementation of legislation and policies desig ...

The behavior of arsenic in chromated copper arsenate containing wood during gasification was modeled using thermodynamic equilibrium calculations. The results of the model were validated using benc ...

WOS: 000387449900001 The aim of this study was to investigate the dimensional stability, mechanical and biological performance and thermal degradation of wood-plastic composites made from high-density polyethylene and recycled wood treated with chromated copper arsenate (CCA), a commonly used wood preservative chemical. Virgin pine wood samples were also prepared with and without a coupling agent and used as the control group. Samples of CCA-treated Scots pine (Pinus sylvestris L.) with varying wood content were produced by adding different ratios of the coupling agent. The recycled CCA-treated wood-filled composites exhibited better flexural and tensile strength properties and dimensional stability than the control group, whilst their impact strength was less. Biological test values showed improved durability against termites and fungus with the recycled CCA-treated wood-filled composites. In addition, the leaching of heavy metals was significantly diminished when the coupling agent was utilized at a level of 5% (w/w), thus presenting a much lower impact on the environment. BAP (Directory of Scientific Research Projects of Duzce University)Duzce University [2010.02.03.057, 2012.02.HD.071] The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was supported by BAP (Directory of Scientific Research Projects of Duzce University) under grant numbers of 2010.02.03.057 and 2012.02.HD.071.

Animal enclosures are often constructed from wood treated with the pesticide chromated copper arsenate (CCA), which leaches arsenic (As) into adjacent soil during normal weathering. This study evaluated potential pathways of As exposure in 25 species of zoo animals living in CCA-wood enclosures. We analyzed As speciation in complete animal foods, dislodgeable As from CCA-wood, and As levels in enclosure soils, as well as As levels in biomarkers of 9 species of crocodilians (eggs), 4 species of birds (feathers), 1 primate species (hair), and 1 porcupine species (quills). Elevated soil As in samples from 17 enclosures was observed at 1.0-110mg/kg, and enclosures housing threatened and endangered species had As levels higher than USEPA's risk-based Eco-SSL for birds and mammals of 43 and 46mg/kg. Wipe samples of CCA-wood on which primates sit had dislodgeable As residues of 4.6-111μg/100cm(2), typical of unsealed CCA-wood. Inorganic As doses from animal foods were estimated at 0.22-7.8μg/kg bw/d. Some As levels in bird feathers and crocodilian eggs were higher than prior studies on wild species. However, hair from marmosets had 6.37mg/kg As, 30-fold greater than the reference value, possibly due to their inability to methylate inorganic As. Our data suggested that elevated As in soils and dislodgeable As from CCA-wood could be important sources of As exposure for zoo animals.

The increasing frequency and severity of wildfires poses human health risks, especially for those within burnt regions. The potential health effects of fire ash on farmworkers in orchards via inhalation exposure after fire is rarely studied. After the 2017 Thomas Fire, in Ventura County (California, USA), fire ash and corresponding soil samples were collected from several impacted orchards and analyzed for eight trace elements (TEs) and 16 polycyclic aromatic hydrocarbons (PAHs). Results indicate that except for mercury (Hg), the concentrations of TEs and PAHs were higher in ash samples compared with the corresponding soil samples. In general, ash samples showed greater potential to expose farmworkers to health risks than the corresponding soil samples. One site had particularly high concentrations of As (778 mg kg−1), Cr (629 mg kg−1), and Cu (499 mg kg−1) in the ash. This location corresponds to a house which was burned during the Thomas Fire, which might have contained chromated copper arsenate as a wood preservative. Therefore, the existence of construction materials in orchards could add hazardous materials to ash deposited on soil. Furthermore, a monitored dust generation experiment was designed to obtain the particle emission factors (PEF) of soil and ash, which is an essential parameter for the calculation of inhalation health risks. A two-fold difference in the PEFs was found between ash and the corresponding soil sample. Hence, health risks through inhalation exposure from fire ash may be underestimated if the default PEF suggested by the US Environmental Protection Agency is used.

Soil samples adjacent to ten CCA-treated utility poles were collected, sieved into four fractions (2 mm, 250-90 μm, 90-20 μm and20 μm), and characterized for their total metal(loid) (As, Cu, Cr, Pb, and Zn) content and physico-chemical properties. Oral bioaccessibility tests were performed using In Vitro Gastrointestinal (IVG) method for fractions 250-90 μm and 90-20 μm. Inhalation bioaccessibility tests were performed in particle size fraction20 μm using two simulated lung fluids: artificial lysosomal fluid (ALF) and Gamble's solution (GS). The total concentration of metal(loid)s increased with decreasing particle size. Oral As bioaccessibility (%) increased with increasing particle size in 9 out of 10 soils (p .05), but oral As bioaccessibility expressed in mg/kg was not significantly different for both particle size. Oral Cu bioaccessibility (% and mg/kg) was not influenced by particle size, but oral Cr bioaccessibility (% and mg/kg) increased when reducing particle size (p .05), although Cr bioaccessibility was very low (8%). Oral bioaccessibility (%) of metal(loid)s decreased in the order: Cu AsPb Zn Cr. Bioaccessibility (%) in simulated lung fluids decreased in the order: Cu Zn AsPb ≈ Cr using ALF, and AsCu using GS solution. For all elements, inhalation bioaccessibility (% and mg/kg) using ALF was higher than oral bioaccessibility, except for Pb bioaccessibility (mg/kg) in two samples. However, solubility of metal(loid)s in GS presented the lowest values. Copper showed the highest oral and inhalation bioaccessibility (%) and Cr showed the lowest. Moreover, organic matter content and cation exchange capacity in particle size 90-20 μm were negatively correlated with Cu and Pb oral bioaccessibility (%).

The aim of this study was to compare the immobilisation of metal(loid)s in two differently contaminated soils using micro zerovalent iron (ZVI) and nano zerovalent iron (nZVI) particles. Chromated copper arsenate-contaminated soil contained high amounts of As, Cu, Cr, and Zn, whereas mining-contaminated soil contained high amounts of As, Cu, and Pb. Contaminated soils were amended using 2% ZVI and nZVI. As determined by the leaching procedures, nZVI was more efficient in immobilising all the studied metal(loid)s in the soils compared to ZVI. The greatest immobilisation was achieved for As in both soils. The long-term stability of immobilised metal(loid)s was studied in mining-contaminated soil by performing thermal oxidation (ageing). In the ZVI and nZVI-treated soils, high retention results were achieved for As and Cu, whereas in the ZVI and nZVI-treated soils, significant desorption of Pb was observed. The results also showed that retention of metal(loid)s over a long period of time could be more effective in soils treated with ZVI, as the crystallisation of Fe in ZVI-treated soil was to a lesser extent compared to the crystallisation of Fe in nZVI-treated soil.

Wood used in playground structures built prior to 2004 was pressure-treated with chromated copper arsenate (CCA) which has been associated with negative health and environmental impacts. Given the prevalence and lack of maintenance of these aging play structures in rural northeastern US, the aim of this study was to determine the distribution of As (total, speciated and bioaccessible) in surface soil collected near and underneath four CCA-treated playground structures 16- and 26-years following installation. Note that one playground in southeastern MA was studied where surface soil samples were collected at various distances from the structures (0, 5, 15, and 30 cm). Total As in surface soil was measured by graphite furnace atomic absorption spectroscopy, whereas As speciation and bioaccessible As were determined by HPLC-ICPMS and in vitro SBRC-gastric assay, respectively. Near (≤5 cm) and underneath CCA-treated structures total As concentration in surface soil ranged from 143.4–213.5 mg/kg after 26 years of installation compared to 101.3–166.6 mg/kg ten years earlier. These concentrations exceeded the Massachusetts Residential Risk-Based Soil Standard by 5–10 times. In comparison, total As in background soil samples ranged from 4.6–6.6 mg/kg during the two study periods. While most of the As in surface soil were in the form of As(V), ≤ 29% was bioaccessible. Overall, our findings demonstrated that arsenic accumulation in soil surrounding aging playground structures continues to be a source of elevated exposure to children through contact with contaminated soil.

Florida geologic units and soils contain a wide range in concentrations of naturally-occurring arsenic. The average range of bulk rock concentrations is 1 to 13.1 mg/kg with concentrations in accessary minerals being over 1000 mg/kg. Florida soils contain natural arsenic concentrations which can exceed 10 mg/kg in some circumstances, with organic-rich soils often having the highest concentrations. Anthropogenic sources of arsenic have added about 610,000 metric tons of arsenic into the Florida environment since 1970, thereby increasing background concentrations in soils. The anthropogenic sources of arsenic in soils include: pesticides (used in Florida beginning in the 1890’s), fertilizers, chromated copper arsenate (CCA)-treated wood, soil amendments, cattle-dipping vats, chicken litter, sludges from water treatment plants, and others. The default Soil Cleanup Target Level (SCTL) in Florida for arsenic in residential soils is 2.1 mg/kg which is below some naturally-occurring background concentrations in soils and anthropogenic concentrations in agricultural soils. A review of risk considerations shows that adverse health impacts associated with exposure to arsenic is dependent on many factors and that the Florida cleanup levels are very conservative. Exposure to arsenic in soils at concentrations that exceed the Florida default cleanup level set specifically for residential environments does not necessarily pose a meaningful a priori public health risk, given important considerations such as the form of arsenic present, the route(s) of exposure, and the actual circumstances of exposure (e.g., frequency, duration, and magnitude).

The physico-chemical factors affecting the distribution, behavior and speciation of chromium (Cr), copper (Cu) and arsenic (As) was investigated at a former wood impregnation site (Fredensborg, Denmark). Forty soil samples were collected and extracted using a sequential extraction technique known as the Chemometric Identification of Substrates and Element Distributions (CISED) and a multivariate statistical tool (redundancy analysis) was applied. CISED data was linked to water-extractable Cr, Cu and As and bioavailable Cu as determined by a whole-cell bacterial bioreporter assay. Results showed that soil pH significantly affected the solid phase distribution of all three elements on site. Additionally, elements competing for binding sites, Ca, Mg and Mn in the case of Cu, and P, in the case of As, played a major role in the distribution of these elements in soil. Element-specific distributions were observed amongst the six identified soil phases including residual pore salts, exchangeable, carbonates (tentative designation), Mn-Al oxide, amorphous Fe oxide, and crystalline Fe oxide. While Cr was strongly bound to non-extractable crystalline Fe oxide in the oxic top soil, Cu and notably, As were associated with readily extractable phases, suggesting that Cu and As, and not Cr, constitute the highest risk to environmental and human health. However, bioavailable Cu did not significantly correlate with CISED identified soil phases, suggesting that sequential extraction schemes such as CISED may not be ideally suited for inferring bioavailability to microorganisms in soil and supports the integration of receptor-specific bioavailability tests into risk assessments as a complement to chemical methods.

The goal of this study was to investigate if it is possible to recycle chromated copper arsenate (CCA)-treated wood for use in wood polymer composites. This was done by soda pulping wood chips of CCA-treated lumber in a laboratory-scale digester. Composites of 10&ndash, 30 weight percentage of filler in polypropylene were produced with and without the addition of maleic anhydride grafted polypropylene (MAPP) as a coupling agent. These composites were produced using extrusion compounding and injection moulding. The mechanical properties were determined using tensile testing, the properties examined in this study are the ultimate tensile strength, Young&rsquo, s modulus and strain at break. The effect of the CCA-treated filler on the dimensional stability was investigated by comparing the moisture absorption with virgin wood-filled composites. It was found that ultimate tensile strength improves with increasing filler percentage for the compositions with MAPP. The Young&rsquo, s modulus increases with increasing filler percentage for all compositions, and failure strain decreases with increasing filler percentage for all compositions. Moisture absorption studies show that the moisture absorption decreases when MAPP is added to the composite, and a slight decrease in moisture uptake is observed for the CCA-treated wood composites with respect to the virgin wood composites.

There is increasing concern about the use of chromated copper arsenate (CCA) treated timber due to the possible leaching of toxic metals or metalloids. CCA-treated timber waste are currently stockpiled across Australia with limited information about their risks to the environment or human health. In this study, the treatment and utilisation of CCA-treated timber waste as garden mulch, garden retaining walls, and soil additive were investigated. Iron materials were used as immobilising agents. The bioavailability of Cr, Cu and As to Spinacia oleracea from CCA-treated timber, before and after treatment, was determined in the context of human health risk assessment. The results showed that the iron-based treatments resulted in significant decreases in the concentrations of Cu and As in spinach grown in CCA-treated timber in soil. Analyses of CCA derived Cu and As in spinach showed that they accumulated in the roots rather than in the leaves. The risks of toxicity to humans varied for different utilisation scenarios and the immobilisation amendments were shown to reduce carcinogenic and non-carcinogenic risks. The information obtained in this study can inform development of utilisation options for CCA-treated timber wastes.

A limitation to recycling wood from construction and demolition (C&D) waste is contamination of metals from the inadvertent inclusion of preservative treated wood, in particular wood treated with chromated copper arsenate (CCA) and newer copper-based formulations. To minimize contamination many regions have developed best management practices (BMPs) for separating treated from untreated wood. The objective of this study was to evaluate the fraction of preservative treated wood in recycled C&D wood after the implementation of BMPs, using Florida as a case study. Methods involved collecting recycled C&D wood samples from throughout the state, measuring metals concentrations (As, Cu, and Cr) in the samples to compute the fraction of recycled wood treated with waterborne wood preservatives, and comparing measurements with those taken prior to the formalization of BMPs. Metals concentrations were measured using two methods, one based on traditional laboratory digestion methods and another using a more rapid hand-held X-ray Fluorescence (XRF) device in the field. The proportion of waterborne preservative-treated wood in recycled wood products has reduced significantly in the intervening 20 years (from 6% to 2.9%), and the fraction of CCA-treated wood has been reduced even further, to 1.4%. The remaining fraction of waterborne preservative-treated wood is comprised of new formulations of copper-based preservatives. This suggests that restrictions from the wood preservation industry and best management practices implemented at recycling facilities have been effective in reducing heavy metal contamination from pressure treated lumber in recycled wood products.