Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Mais filtros

Base de dados
Intervalo de ano de publicação
Mycologia ; 111(5): 703-718, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31348726


Timber durability is often assessed using small wood stakes exposed in direct soil contact, and the assessment generally emphasizes effects on wood rather than organisms involved. Understanding fungal colonization patterns can help identify key decay agents under varying conditions and use these patterns to improve wood protection strategies. Fungal colonization of red alder (Alnus rubra), Douglas-fir (Pseudotsuga menziesii) heartwood/sapwood, and western redcedar (Thuja plicata) field stakes was assessed over 2 y in western Oregon. Spatiotemporal fungal community variations were identified via culturing and DNA sequencing, where 814 isolates were identified from 84 stakes. Forty-six ascomycete genera were identified, with Phialophora, Trichoderma, and Epicoccum species occurring most frequently. Twenty-three basidiomycete genera were identified, with Trametes and Phanerochaete being the most common. Douglas-fir and western redcedar stakes contained the highest and lowest diversity levels, respectively, reflecting natural durability differences of these species. Fungal species abundance was higher below ground than in the above ground and groundline zones, likely reflecting more stable moisture regimes, proximity to soil-based fungi, and potential nutrient migration into wood beneath the soil surface. Ascomycetes were proportionally more abundant early in the exposure period, but basidiomycetes were also observed early in the process, and there appeared to be no consistent colonization pattern.

Environ Sci Pollut Res Int ; 26(19): 19598-19605, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31077053


The ability of standard soils to capture heavy metals or polycyclic aromatic hydrocarbons (PAHs) from ammoniacal copper zinc arsenate (ACZA)- or creosote-treated wood, respectively, was assessed using pressure-treated posts immersed in a freshwater pond. The soil, in heat-sealed, permeable plastic mesh sachets, was able to intercept copper, zinc, arsenic, and PAHs migrating from the posts. Chemical levels were much higher immediately adjacent to the posts and declined with distance from the posts. Metals were consistently detected around ACZA-treated posts, while 10 of the 16 EPA priority pollutants were detected in at least one sachet embedded around creosote-treated posts at each sampling point. These results were consistent with traditional sediment sampling methods. The primary advantages of the sachets were their consistency in terms of soil characteristics and the ease with which they could be retrieved from the pond. Further studies are planned to better understand the role of soil characteristics in the sachets on the ability to capture migrating preservatives.

Monitoramento Ambiental/métodos , Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Solo/química , Madeira/química , Arseniatos/análise , Cobre/análise , Creosoto/análise , Recuperação e Remediação Ambiental/instrumentação , Desenho de Equipamento , Polímeros/química , Zinco/análise
J Environ Manage ; 203(Pt 1): 273-277, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28800424


The potential for migration of pentachlorophenol (PCP) and copper naphthenate (CuNaph) from Douglas-fir was assessed in a bridge over a stream located in Western Oregon in the United States. All rainfall runoff was collected from a portion of the bridge on 15 occasions over a 27 month period and analyzed for pentachlorophenol or copper. PCP and copper were detected at every time point. PCP concentrations ranged from 0.296 to 6.183 µg/mL, while those for copper ranged from 0.37 to 7.80 µg/mL. These data were then used to estimate PCP and Cu inputs in runoff from the entire bridge. Stream flow data were then used to predict the concentrations that would develop in the receiving stream. The results showed that runoff from the bridge would result in PCP and copper concentrations that were 500-1000 times lower than the reported levels of effect for each component. The results are discussed in the context of this location as well as other sites with lower stream flow conditions.

Pentaclorofenol , Abies , Cobre , Poluentes Ambientais/química , Oregon
J Environ Manage ; 152: 268-72, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25659940


Migration of heavy metals into aquatic environments has become a concern in some regions of the world. Many wood preservatives are copper based systems that have the potential to migrate from the wood and into the surrounding environment. Some wood treaters have developed "best management practices" (BMPs) that are designed to reduce the risk of migration, but there are few comparative studies assessing the efficacy of these processes. The potential for using various heating combinations to limit copper migration was assessed using ammoniacal coper zinc arsenate treated Douglas-fir lumber. Kiln drying and air drying both proved to be the most effective methods for limiting copper migration, while post-treatment steaming or hot water immersion produced more variable results. The results should provide guidance for improving the BMP processes.

Arseniatos/química , Cobre/química , Recuperação e Remediação Ambiental/métodos , Poluentes Químicos da Água/análise , Poluição Química da Água/prevenção & controle , Madeira/química , Monitoramento Ambiental , Pseudotsuga , Chuva
Tree Physiol ; 27(6): 921-7, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17331910


Heartwood extractives (nonstructural wood components) are believed to be formed from a combination of compounds present in the adjacent sapwood and materials imported from the phloem. The roles of local compounds and imported material in heartwood formation could have important implications for the wood quality of species having naturally durable wood. Stable isotope composition (delta(13)C) was analyzed to assess radial variation in sapwood extractives, and to estimate the relative importance of adjacent sapwood extractives and imported photosynthate in the formation of heartwood extractives. Cellulose and extractives from the outer 39 annual rings of six Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees were isolated and their delta(13)C composition determined. Although the extractives and the cellulose showed different absolute delta(13)C values, the patterns of change over time (as represented by the annual rings) were similar in most cases. Within an annual ring, carbon isotope ratios of extractives were correlated with the cellulose isotope ratio (R2 = 0.33 in sapwood, R2 = 0.34 in heartwood for aqueous acetone-soluble extractives; R2 = 0.41 in sapwood for hot-water-soluble extractives). These data suggest that some sapwood extractives are formed when the wood ring forms, and remain in place until they are converted to heartwood extractives many years later. Sapwood extractives appear to be important sources of materials for the biosynthesis of heartwood extractives in Douglas-fir.

Isótopos de Carbono/metabolismo , Celulose/metabolismo , Exsudatos de Plantas/metabolismo , Pseudotsuga/metabolismo , Xilema/metabolismo , Transporte Biológico , Fatores de Tempo