Natural durability and improved resistance of 20 Amazonian wood species after 30 years in ground contact

This study aimed to assess the natural durability of 20 Amazonian wood species preserved with chromated copper arsenate (CCA) after 30 years in ground contact in an experimental field test at National Forest of Tapajós, Pará state - Brazil. Heartwood samples with a cross-section of 5 × 5 cm and 50 cm of length were half-buried in soil and inspected every year for decay. The species were classified according to natural durability following the classification method proposed by Findlay (Findlay, W.P.K. (1985). The nature and durability of wood. In: Findlay, W.P.K. (Ed.), Preservation of timber in the tropics. Springer Science, Whitchurch, pp. 1–13). After 30 years in ground test, six species were classified as Perishable, seven as Non-durable, three as Durable and four as Very durable, namely: Trichilia lecointei, Lecythis pisonis, Pseudopiptadenia suaveolens, and Dipteryx odorata (Very durable), Protium tenuifolium, Dinizia excelsa, and Ormosia paraensis (Durable), Endopleura uchi, Goupia glabra, Pouteria egregia, Tachigali chrysophylla, Tachigali paraensis, Vatairea sericea, and Vochysia maxima (Non-durable) and Chrysophyllum lucentifolium, Couratari oblongifolia, Didymopanax morototoni, Lueheopsis duckeana, Sterculia excelsa, and Xylopia nitida (Perishable). CCA preservative treatment was effective to promote timber protection, even under harsh climatic conditions of the Amazon forest environment.

Electro-removal of copper, chromium, and arsenic from chromated copper arsenate treated waste wood

ABSTRACT 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.

Macrophyte Potential to Treat Leachate Contaminated with Wood Preservatives: Plant Tolerance and Bioaccumulation Capacity

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 µg/L in the leachate) and 50 mg As/kg (from 330 µg/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.

Mobility of Chromium, Copper and Arsenic in Amended Chromated Copper Arsenate Contaminated Soils

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.

Illite crystallinity index an indicator of physical weathering of the Sediments of the Tista River, Rangpur, Bangladesh

The Tista River is a tributary of the Brahmaputra River. The deposits that exposed along the both banks of the Tista River are characterized mainly by sand, sand laden with gravel and pebble with minor amounts of silt and clay. The X-ray Diffraction (XRD) of the clay sized sediments of the Tista River reveals that illite (and/or mica), chlorite, kaolinite, quartz and feldspar are the principal mineral constituents. The minor to trace amounts of lavendulan, glauconite lepidolite, enstatite, sekaninaite and ferrierite minerals were identified in the investigated area. Illite constitutes 36% of the total minerals of the Tista River basin. The values of the illite crystallinity index varies from 0.228 to 0.345, indicating that the illites are relatively well crystallized and derived from the mechanical weathering of pre-existing rocks. The presence of illite and kaolinite suggests their derivation from the crystalline rocks that contain feldspar and mica, as well as from the pre-existing soils and sedimentary rocks. Glauconite forms in the sediments of continental shelf in the marine environment. The accessory minerals like enstatite, sekanianite and ferrierite are derived from basic igneous rocks. The dissolution of copper arsenate mineral, lavendulan might be a source of arsenic in the sediments of the study area.

Physical and mechanical behavior of glulam beams produced with rubberwood treated with preservatives

ABSTRACT This work aimed to evaluate the physical and mechanical behavior of glued laminated timber (GLT) - glulam pieces of Hevea brasiliensis treated with chromed copper arsenate (CCA), chromed copper borate (CCB) and pyrethroid in the production of GLT. The pieces were produced using three wooden laminae with dimensions of 60 x 20 x 1200 mm, (width x thickness x length), joined with epoxy adhesive under 1.0 MPa pressure for 24h at room temperature. The rubberwood had an apparent density of 0.624 g cm-3, a value close to that of Eucalyptus grandis wood, a species traditionally used in the manufacture of GLT. Regarding the GLT parts, it was observed that the preservative treatment with CCA and CCB influenced negatively the values of the mechanical properties. For resistance modulus (MOR), a reduction of 75.44 MPa to 62.36 and 58.57 MPa was found for the parts untreated and treated with CCA and CCB, respectively. There was no statistical difference for surface treatment with pyrethroid. The photomicrographs of the glue line showed that the reduction in these values was mainly due to the penetration of preservative solutions into the wood structure (cell lumens and vessels or pores), impairing the anchoring of the adhesive.