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PubMed2007

Evaluation of methods for sorting CCA-treated wood.

Construction and demolition (C&D) wood frequently contains treated wood including wood treated with chromated copper arsenate (CCA). Many recycling options for such wood require that the product be essentially free of preservative chemicals. The objectives of this study were to document the characteristics of the wood waste stream and to evaluate the effectiveness of sorting methods for identifying treated wood. Sorting methods evaluated included visual sorting and visual sorting augmented with the use of PAN indicator stain and/or hand-held X-ray fluorescence (XRF) units. Experiments were conducted on two types of construction and demolition (C&D) wood: source separated loads containing only C&D wood and wood hand-picked from commingled loads of general C&D waste. Results showed that 77% of the treated wood was CCA-treated. For uncontaminated piles (<1% treated wood) of source separated C&D wood, visual sorting was found to effectively remove the small amounts of treated wood present. For piles of source separated wood that were contaminated (approximately 50% treated wood), visual sorts were not accurate and benefited from augmented sorting using PAN indicator stain. The handheld XRF devices were found to be effective for sorting commingled C&D wood, as PAN indicator stain was not as effective due to the excessive amount of surface dirt associated with commingled wood waste. Visual sorting of source separated wood was estimated to cost between US$21 to US$96 per metric ton. These costs depended upon the amount of treated wood and whether or not augmentation with PAN indicator was necessary. Visual sorting augmented with hand-held XRF units was estimated at US$113 per metric ton. The bulk of these costs were associated with labor. Future efforts should focus on reducing labor costs by mounting automated XRF units on conveyor systems.

Arsenates↗
PubMed1998

The role of combination effects on the etiology of malignant nasal tumours in the wood-working industry.

Adenocarcinomas of the nose are regarded as an occupational disease in Germany and other European countries, and workers exposed to oak or beech wood-dust in the course of their work receive compensation if they incur adenocarcinoma of the nose. This has prompted a joint research project to record the functional and morphological changes of the nasal mucosa and/or paranasal sinus of 149 exposed subjects and 33 controls in accordance with a defined occupational exposure. To ensure the quantitative and qualitative reliability of the exposure data, 1,349 measurements at the company workplace were taken and analyses of 614 wood samples performed; parallel to this, the genotoxic effects of the most important substances used in the wood-working industry were tested. Apart from this, latency periods and morbidity rates in Germany were investigated. Partial findings of this research projects have been evaluated by the International Agency for Research on Cancer (IARC). According to these evaluations and the findings presented here, the following points can be made: i) Morphological changes in the nasal mucosa after exposure to wood-dust resulted in an increase in cylindrocellular hyperplasias and, in functional terms, a tendency towards improved nasal clearance was observed. Chromium and formaldehyde, on the other hand, tended to give rise to an increase in the number of squamous metaplasias. This might explain the preference for the histological types of adenocarcinoma among subjects exposed to wood-dust. ii) In tissue samples more dysplasias were found among those exposed to oak and beech wood-dust. Subjects exposed to wood preserving agents had dysplasias only if they were simultaneously exposed to oak and beech wood-dust. The latter effect did not quite reach the level of significance (p = 0.07) on account of the low numbers of cases. iii) The investigation of genotoxic effects showed that oak and beech contain genotoxic substances that can be dissolved by means of ethanol and cyclohexane; they also showed that 3 out of 8 wood preservatives, 5 out of 16 stains, and 2 out of 11 paints from the wood-working industry are genotoxic too. Apart from this, lindane and PCP have proved to be genotoxic in the nasal cells of rats and human beings. Analysis of 614 wood samples from wood-preserving agents showed that almost 73% contained agents of this type, even in woods described by the companies as being guaranteed free of wood preservatives. iv) According to an analysis of 147 cases accepted since 1985 as a pensionable occupational illness by the Holz-Berufsgenossenschaft (an industrial compensation society for employees in the wood-working industry), the disease was much more apparent in small companies where there is multi-factorial exposure, than in large companies where the exposure factor tends to have a single component. This points to the combined effects of hardwood dusts and chemicals as being the cause. v) According to published findings, the incidence of the disease in England seems to be on the decline. In Germany, increasing latency periods also point to a decline in the number of cases, although both countries have only very recently introduced effective prevention measures against exposure to wood-dust. This also leads to the assumption that wood-dusts cannot be the only cause of this type of cancer. vi) These findings tally with the evaluation by the IARC confirming the special part that hardwood dusts play in the development of nasal cancer. The findings presented here also indicate combined effects as being the cause of this type of cancer. This hypothesis cannot be confirmed until the conclusion of long-term animal experiments, currently being conducted, to test how the effects of chemicals such as lindane, PCP, and chromate compare with use of oak wood-dust.

Adenocarcinoma↗
PubMed1993

Carcinogenic effects of wood dust: review and discussion.

Occupational exposure to wood dust (alone or chemically treated) is associated with an increased risk of developing adenocarcinoma of the nasal cavity. The specific causative agents, i.e., wood dust alone (natural products), wood dust with additives used in the processing or manufacturing of wood products, and/or physical determinants of wood dust and the associated risk factors, are not known or understood. The strongest association of exposure to wood dust and development of nasal cancer is observed in those occupations where workers are exposed to hard wood dust and chemical additives are not used. The time between first occupational exposure to wood dust and the development of adenocarcinoma of the nasal cavity averages 40 years (range 7-70 years). The epidemiological data available are not sufficient to make a definitive assessment between wood dust exposure and increased risk for cancer other than nasal cancer. The toxicity, mutagenicity, and carcinogenicity of wood dust to laboratory animals or in vitro with animal or microbial cells have not been thoroughly studied. Thus there is no direct experimental evidence on the potential hazards of wood dust. Data are insufficient or lacking on 1) wood dust exposure levels in ambient air and worker's breathing zone, and the deposition in the nasal cavity; 2) hard vs. soft wood dusts; 3) particle size and shape; 4) chemical composition of wood dust and the extent of contamination with chemical additives; and 5) interaction between inhaled wood dust, chronic irritation, and tobacco smoking. These data are required so that one can understand the association between wood dust exposure and nasal cavity tumors, along with demographic differences in cancer rates, and to develop strategies for intervention and reduction of disease causing agents in order to reduce risk to wood industry workers.

Animals↗
PubMed2003

Seasonal variation in transcript accumulation in wood-forming tissues of maritime pine (Pinus pinaster Ait.) with emphasis on a cell wall glycine-rich protein.

Wood formation is being increasingly studied at cellular and biochemical levels; however, gene expression and regulation during wood formation remain poorly understood. Up to six types of wood can be studied within the same tree (early wood, late wood, juvenile wood, mature wood, reaction wood and opposite wood). These six types are characterized by different chemical, physical and anatomical properties. Using the cDNA-amplified fragment length polymorphism (AFLP) technique, we screened several thousand cDNA fragments from differentiating xylem of maritime pine (Pinus pinaster Ait.) comparing early wood vs. late wood and compression wood vs. opposite wood after 8 or 120 days of bending. About 100 transcript-derived fragments (TDFs) showed qualitative or quantitative variations between these different samples. The relative abundance of these TDFs was subsequently analyzed by reverse Northern using RNA derived from early and late wood. Analysis of variance (ANOVA) was used to identify differentially expressed TDFs ( P<0.01) and reverse transcription-polymerase chain reaction to confirm the differential expression of some TDFs. Among the genes with a known function, transcript expression and nucleotide sequence variation analysis showed a cell wall glycine-rich protein to be a strong candidate gene for wood properties.

Blotting, Northern↗
PubMed2005

Implication of chromium speciation on disposal of discarded CCA-treated wood.

The wood preservative chromated copper arsenate (CCA) contains hexavalent chromium [Cr(VI)] and the conversion of Cr(VI) to trivalent chromium [Cr(III)] drives fixation of the treatment chemicals to the wood fibers. Since the toxicity of Cr depends on its valence state, an assessment of the Cr species occurring in CCA-treated wood, as well as leachates and ashes from CCA-treated wood, is helpful when assessing implications for disposal. In this study, both new and weathered wood samples of CCA-treated wood and their ashes were evaluated for total Cr and Cr(VI) within the solid matrices and within leachates. Results show that for both new and weathered CCA-treated wood, Cr(VI) occurred in the range of 0.7-4% of the total Cr. Greater Cr leaching occurred at the pH extremes, with Cr(VI) only measured under alkaline pH values (pH > 9.0). Total chromium concentrations from synthetic precipitation leaching procedure (SPLP) leachates from CCA-treated wood were consistently less than 3mg/L with Cr(VI) below detection limits. The results suggest that leaching of Cr(VI) from discarded CCA-treated wood should not be a concern in most landfill environments. One exception would be disposal in landfills with alkaline leachate; Cr(VI) was observed to leach from CCA-treated wood in the presence of alkaline leachate from crushed concrete. When CCA-treated wood is combusted, chromium becomes concentrated in the ash. Cr(VI) in ash from the combustion of CCA-treated wood was found between 4 and 7% of the total chromium. In ash from the combustion of wood recovered from construction and demolition (C&D) debris (which contained some CCA-treated wood), Cr(VI) accounted for as much as 43% of the total Cr. Nearly, all of the Cr in SPLP leachates produced from the ash was in the Cr(VI) form. The degree of Cr(VI) leaching from the ash was highly dependent upon the alkalinity of the ash, with higher ash leachate pH resulting in greater concentrations of Cr(VI).

Arsenates↗
PubMed2005

Treated wood preservatives linked to aquatic damage, human illness, and death--a societal problem.

On February 12, 2002, the US Environmental Protection Agency (EPA) announced a voluntary decision by industry to move consumer use of treated lumber products away from a variety of pressure-treated wood that contains arsenate (As) by December 31, 2003, in favor of new alternative wood preservatives. Chromated copper arsenate (CCA) is a chemical mixture consisting of three pesticidal compounds (As, chromium, and copper) registered for wood preservative uses. CCA is injected into wood by a process that uses high pressure to saturate wood products with the chemical. Only people who have received the proper safety training should use CCA to treat wood products. Around the home, CCA-treated wood is commonly used for decks, walkways, fences, gazebos, boat docks, and playground equipment. Other common uses of CCA-treated wood include highway noise barriers, sign posts, utility posts, and retaining walls. As of January 1, 2004, the EPA is no longer allowing CCA products to be used to treat wood intended for any of these residential uses. This decision will facilitate the voluntary transition to new alternative wood preservatives that do not contain As in both the manufacturing and retail sectors. To its credit, the EPA has developed consumer safety information sheets, hanging signs, end signs, and bin stickers that provide comprehensive information about the dangers of CCA-treated wood, use-site, and handling precautions. The EPA has not concluded that CCA-treated wood poses any unreasonable risk to the public or the environment. Nevertheless, As is a known human carcinogen and, thus, the EPA believes that any reduction in the levels of potential exposure to As is desirable. The toxicologic manifestations have been primarily related to the effects of As exposure from drinking water sources and include the following: acute poisoning incidents, cardiovascular effects, diabetes mellitus, and cancer. Understanding the biomethylation of As is central to elucidating its action as a toxin and a carcinogen. In humans as in many other species, inorganic As is enzymatically converted to the methylated products methyl As (MAs) and dimethyl As (DMAs). The aforementioned voluntary agreement to reduce the uses of CCA-treated wood does not include a ban on the use of CCA for residential roofing. A major reason that this wood product should be banned from residential roofing is that it does not provide a Class "A" fire-rated roof system, which markedly reduce the frequency of residential roof fires.

Arsenic Poisoning↗
PubMed2005

Amount of leachant and water absorption levels of wood treated with borates and water repellents.

Wood protection efficacy of borates against biological agents, flame retardancy, and suitability to the environment is well known. Since borates can be applied to timber as water based solutions, they are preferred economically as well. Even though they are highly mobile in wood, boron compounds are widely used in timber preservation. Borates migrate in liquid and increase the hygroscopicity of wood in damp conditions. This study deals with the physical restriction of water access in wood by impregnating water repellent agents into wood to limit amount of leachant and water absorption levels of wood after boron treatment. Borates were incorporated with polyethylene glycol-400 (PEG-400) their bulking effect in wood was considered. Results indicated that the amount of leachates from wood treated with borates in PEG-400 was remarkably higher compared to those of wood treated with the aqueous solutions of borates. Water absorption (WA) levels of wood treated with aqueous solutions of borates were higher than those of their treated samples with the solutions in PEG-400. Secondary treatments of wood with the water repellent (WR) chemicals following borate impregnation reduced the leaching of chemicals from wood in water and also WA of the specimens were less than those of the wood treated with only borates from aqueous and PEG solutions. Styrene (St) was the most effective monomer among the other agents used in terms of immobility effect on borates and WA.

Borates↗
PubMed2004

Significance of wood terpenoids in the resistance of Scots pine provenances against the old house borer, Hylotrupes bajulus, and brown-rot fungus, Coniophora puteana.

We tested how terpenoid (i.e., monoterpenes and resin acids) composition and concentration in wood affects resistance against wood-borers and decaying fungi. Scots pine (Pinus sylvestris) wood from nine provenances having variable terpenoid profiles was studied against the old house borer, Hylotrupes bajulus, and the decay fungus, Coniophora puteana. Provenances represented a 1200-km N-S transect from Estonia to northern Finland, but they were all cultivated for 7 years in the same nursery field, in central Finland. Mean relative growth rate (MRGR) of small H. hajulus larvae positively correlated with the total monoterpene concentration of wood, and feeding was associated with high proportion of levopimaric+palustric acid in wood. Provenance did not affect the MRGR of small or big larvae, but big larvae consumed more wood and produced more frass on the northern Ylitornio trees than on the southern Rakvere and Ruokolahti trees. Low beta-pinene and total monoterpene concentration and low beta: alpha-pinene ratio in wood were all associated with a high number of eggs. The most northern Muonio provenance was the most favored as an oviposition site, differing significantly from Saaremaa, Tenhola, and Suomussalmi. Wood from Saaremaa, Tenhola, Ruokolahti, and Suomussalmi provenance was most resistant against decay fungus, differing significantly from that of Kinnula provenance. However, decay resistance was not clearly associated with the concentrations of wood terpenoids. These results suggest that monoterpene composition of wood affects resistance against wood-boring Cerambycid beetles, but resistance against wood-decaying fungi is not as clearly associated with wood terpenoids.

Adaptation, Physiological↗
PubMed2002

Characteristics of chromated copper arsenate-treated wood ash.

The combustion of recovered wood from construction and demolition waste as biomass fuel is a common practice. When chromated copper arsenate (CCA)-treated wood is present as part of the wood fuel mix, concentrations of arsenic, chromium, and copper become elevated in the ash. The objectives of this study were to estimate the fraction of CCA-treated wood needed to cause the ash to fail regulatory guidelines and to test a series of solvents for the purpose of extracting the metals from the ash. Ash samples were prepared in an industrial furnace using samples of CCA-treated wood, mixtures of CCA-treated wood and untreated wood, and recycled wood waste collected at construction and demolition recycling facilities. Regulatory guidelines were evaluated by measuring total metals concentrations (using neutron activation analysis) and by conducting standardized leaching tests (toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP)) on the ash. Ten different solvents, ranging from distilled water to strong acids, were also tested for their ability to extract metals. Results of this study indicate that metal concentrations (chromium plus copper plus arsenic) can be as high as 36% of the ash by weight for treated wood samples containing high retention levels (40 kg/m(3)) of CCA. All ash samples from the combustion of 100% CCA-treated wood and mixtures containing 5% CCA-treated wood leached enough arsenic (and sometimes chromium) to be characterized as a hazardous waste under US regulations. Concentrated nitric acid, which was the most effective solvent tested, was capable of removing between 70 and 100% of the copper, between 20 and 60% of the chromium, and 60 and 100% of the arsenic for samples characterized by low retention levels. A particular finding of interest was the efficiency of distilled water and other weak solvents to extract measurable amounts of chromium, especially for ash samples containing low retention levels of CCA. Citric acid was particularly effective at removing arsenic (between 40 and 100%) for ash samples produced from wood containing low CCA retention levels.

Arsenates↗
PubMed2004

Arsenic speciation of solvent-extracted leachate from new and weathered CCA-treated wood.

For the past 60 yr, chromate-copper-arsenate (CCA) has been used to pressure-treat millions of cubic meters of wood in the United States for the construction of many outdoor structures. Leaching of arsenic from these structures is a possible health concern as there exists the potential for soil and groundwater contamination. While previous studies have focused on total arsenic concentrations leaching from CCA-treated wood, information pertaining to the speciation of arsenic leached is limited. Since arsenic toxicity is dependent upon speciation, the objective of this study was to identify and quantify arsenic species leaching from new and weathered CCA-treated wood and CCA-treated wood ash. Solvent-extraction experiments were carried out by subjecting the treated wood and the ash to solvents of varying pH values, solvents defined in the EPA's Synthetic Precipitation Leaching Procedure (SPLP) and Toxicity Characteristic Leaching Procedure (TCLP), rainwater, deionized water, and seawater. The generated leachates were analyzed for inorganic As(III) and As(V) and the organoarsenic species, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), using high-performance liquid chromatography followed by hydride generation and atomic fluorescence spectrometry (HPLC-HG-AFS). Only the inorganic species were detected in any of the wood leachates; no organoarsenic species were found. Inorganic As(V) was the major detectable species leaching from both new and weathered wood. The weathered wood leached relatively more overall arsenic and was attributed to increased inorganic As(III) leaching. The greater presence of As(III) in the weathered wood samples as compared to the new wood samples may be due to natural chemical and biological transformations during the weathering process. CCA-treated wood ash leached more arsenic than unburned wood using the SPLP and TCLP, and ash samples leached more inorganic As(III) than the unburned counterparts. Increased leaching was due to higher concentrations of arsenic within the ash and to the conversion of some As(V) to As(III) during combustion.

Arsenates↗
PubMed2002

Pilot scale evaluation of sorting technologies for CCA treated wood waste.

Two sorting technologies including a chemical stain method and an x-ray fluorescence technique were investigated for separating chromated copper arsenate (CCA) treated wood from other wood types in the wood waste stream. Stains were investigated in both laboratory and field settings. Studies included specially mixed solutions with chrome azurol, 1-(2-pyridylazo)-2-naphthol (PAN) and rubeanic acid chemicals. X-ray fluorescence was tested in the laboratory using a commercially available x-ray fluorescence spectrometer. Laboratory scale experiments showed that both technologies were able to detect CCA treated wood in mixtures of treated wood and untreated wood, with detection limits on the order of 3 to 5% CCA. Results from field experiments at construction and demolition facilities indicate that although the chemical stains can be effectively used to identify CCA treated wood waste in field settings, their use will be limited to sorting relatively small wood waste piles due to increased labor and time needed for processing the wood waste. Operational parameters for sorting using x-ray fluorescence technology were established. These parameters concluded that arsenic was the most sensitive metal for analysis, analysis time was less than 2 seconds per wood sample, and the maximum separation distance between the sample and the x-ray probe was 2.5 cm. X-ray technology shows considerable promise for separating large quantities of CCA-treated wood from other wood types in the field using an on-line sorting system.

Arsenates↗
PubMed2006

Regional and phylogenetic variation of wood density across 2456 Neotropical tree species.

Wood density is a crucial variable in carbon accounting programs of both secondary and old-growth tropical forests. It also is the best single descriptor of wood: it correlates with numerous morphological, mechanical, physiological, and ecological properties. To explore the extent to which wood density could be estimated for rare or poorly censused taxa, and possible sources of variation in this trait, we analyzed regional, taxonomic, and phylogenetic variation in wood density among 2456 tree species from Central and South America. Wood density varied over more than one order of magnitude across species, with an overall mean of 0.645 g/cm3. Our geographical analysis showed significant decreases in wood density with increasing altitude and significant differences among low-altitude geographical regions: wet forests of Central America and western Amazonia have significantly lower mean wood density than dry forests of Central and South America, eastern and central Amazonian forests, and the Atlantic forests of Brazil; and eastern Amazonian forests have lower wood densities than the dry forests and the Atlantic forest. A nested analysis of variance showed that 74% of the species-level wood density variation was explained at the genus level, 34% at the Angiosperm Phylogeny Group (APG) family level, and 19% at the APG order level. This indicates that genus-level means give reliable approximations of values of species, except in a few hypervariable genera. We also studied which evolutionary shifts in wood density occurred in the phylogeny of seed plants using a composite phylogenetic tree. Major changes were observed at deep nodes (Eurosid 1), and also in more recent divergences (for instance in the Rhamnoids, Simaroubaceae, and Anacardiaceae). Our unprecedented wood density data set yields consistent guidelines for estimating wood densities when species-level information is lacking and should significantly reduce error in Central and South American carbon accounting programs.

Altitude↗
PubMed1985

Health hazards of natural and introduced chemical components of boatbuilding woods.

The major components of untreated wood--cellulose, hemicellulose, and lignin--have not been implicated as toxicants, but extractive substances, especially in heartwood, can be toxic. Decay-resistant woods are more likely to contain irritants or sensitizers than nondurable woods. Short-term exposures to certain wood dusts may result in asthma, conjunctivitis, rhinitis, or allergic dermatitis, but long-term effects may include nasal cancer and Hodgkin's disease. Some thermophilic microorganisms found in wood are human pathogens, and septic splinters (chromomycosis) and inhalation of ascomycete spores from stored wood chips have been implicated in human illnesses. Reconstituted wood can contain formaldehyde resins, which pose health risks in enclosed humid areas. Pentachlorophenol (PCP)-treated wood is particularly toxic--short-term exposures to PCP-treating solutions can lead to aplastic anemia and mortality, while diseases such as Hodgkin's disease are associated with long-term exposures. Since much commercial lumber is dipped in PCP, the separation of the chronic effects of wood dust from PCP exposure is difficult. Chromated copper arsenate (CCA)- and ammoniacal copper arsenite (ACA)-treated wood may leach arsenic. CCA-treated wood is potentially safer, since it contains the pentavalent arsenic, which is a common constituent in the environment. ACA contains the trivalent arsenic, which is more toxic.

Arsenates↗
PubMed2006

Evaluating landfill disposal of chromated copper arsenate (CCA) treated wood and potential effects on groundwater: evidence from Florida.

Chromated copper arsenate (CCA) treated wood has been used for more than 50 years. Recent attention has been focused on appropriate disposal of CCA-treated wood when its service life ends. Groups in the US and Europe concerned with the possibility of arsenic migration to groundwater from disposed CCA-treated wood have proposed that consumers be required to dispose of the wood as a hazardous waste, in the most protective of landfills. We examined available data for evidence of arsenic migration from unlined construction and demolition (C&D) debris landfills in Florida, where CCA-treated wood is disposed. Florida was chosen because soil, groundwater, landfill design, weather, and levels of CCA-treated wood use make the state a uniquely sensitive indicator for observing arsenic migration from CCA-treated wood disposal sites, should it occur. We developed and quality-checked a CCA-treated wood disposal model to estimate the amount of wood and associated arsenic disposed. By 2000, an estimated 13 million kg of arsenic in CCA-treated wood was disposed in Florida; however, groundwater monitoring data do not indicate that arsenic is migrating from unlined C&D landfills. Our results provide evidence that highly stringent regulation of CCA-treated wood disposal, such as treatment as a hazardous waste, is unnecessary.

Arsenates↗
PubMed2006

Effects on growth, photosynthesis and pigments of the freshwater moss Fontinalis antipyretica Hedw. after exposure to wood ash solution.

The application of wood ash from biofuel sources to the forest has been suggested as a source of nutrients for trees and for restoration of acidified soils and surface waters. Studies on the effects of wood ash on aquatic organisms and ecosystems are, however, few. This study investigated the effects of wood ash (0.1-10 g l(-1)) on the freshwater moss Fontinalis antipyretica Hedw., which has previously been shown to be a sensitive test organism for assessing environmental pollution. After nine weeks of treatment with wood ash, a significant effect of enhanced stem growth was observed at higher concentrations (1-10 g l(-1)). The concentration of wood ash was also correlated with the growth of secondary branches. Photosynthesis (oxygen evolution after 4 h of exposure to wood ash) was significantly lower in the alkaline treatments (no pH adjustment) compared to the treatments with neutral wood ash solutions (pH adjusted to 7.5). Furthermore, photosynthesis in the alkaline wood ash treatments was significantly lower compared to the control. The ratio between the optical density value before and after acidification (OD(665/665a)) was higher for all wood ash concentrations compared to the control. The OD(665/665a) values ranged from 1.52 to 1.61 and there was a difference, however not significant, between the alkaline and the neutral treatment at 10 g l(-1) wood ash. This study clearly demonstrated that wood ash may be beneficial for F. antipyretica at moderate concentrations (0.5-5 g l(-1)), particularly when a sudden increase in pH is avoided.

Bryopsida↗
PubMed2005

Survival and feeding responses of Anacanthotermes ochraceus (Hodotermitidae: Isoptera) to local and imported wood.

Forty-six local and imported wood were tested for resistance to feeding damage by the termite Anacanthotermes ochraceus (Burmeister), the most dominant species in the United Arab Emirates and the Arab Gulf region. Wood was used for construction, wall paneling, and furniture. Wood was evaluated in a 4-wk forced feeding bioassay. Each wood block was graded by the amount of termite damage by using a damage rating index (DRI) of 0 to 5 and wood rating index from very resistant to very susceptible wood. Local wood was mostly susceptible to feeding of termites; imported wood varied in resistance to feeding damage. Wood was placed in groups according to the percentages of weight loss (WL), termite survival (TS), and DRI. Wood was classified as very resistant (%WL from 0.0 to 0.3, %TS from 0.01 to 0.5, and DRI of 0.01), resistant (%WL from 1.1 to 4.9, %TS from 0.8 to 4.8, and DRI of 1.0), moderately resistant (%WL from 6.6 to 9.3, %TS from 6.3 to 8.3, and DRI of 2.0-2.3), slightly resistant (%WL from 10.1 to 19.9, %TS from 9.5 to 28.0, and DRI of 2.5-3.5), susceptible (%WL from 21.5 to 48.6, %TS from 37.3 to 64.8, and DRI of 4.0-4.3) and very susceptible (%WL from 50.0 to 59.8, %TS from 72.8 to 79.0, and DRI of 4.5-5.0). The characterization of the extracts of resistant wood may prove of economic value and lead to the development of new chemicals (repellents or antifeedants) for termite control.

Animals↗
PubMed2002

In vitro bioavailability of heavy metals in pressure-treated wood dust.

Pressure treatment with chromium, copper, and arsenic (CCA) is the most prevalent method for protecting wood used in outdoor construction projects. Although these metals are tightly bound to the wood fibers and are not released under most conditions of use, we examined the bioavailability of metals in CCA pressure-treated wood dust in vitro. Cytotoxicity and metallothionein (MT) mRNA expression were examined in V79 Chinese hamster lung fibroblast cells incubated with respirable-size wood dust generated by sanding CCA-treated and untreated (control) Southern yellow pine. In colony survival studies, increased cytotoxicity (p < 0.05) occurred in V79 cells treated with CCA wood dust (351 +/- 77 microg/ml, mean +/- SE) compared with control wood dust (883 +/- 91 microg/ml). Increased cytotoxicity with CCA wood dust also occurred in an arsenic resistant subline of V79 cells, thus suggesting that arsenic was not responsible for the increased cytotoxicity. Metallothionein mRNA was significantly increased after 48 h of treatment with CCA wood dust compared with control wood dust. Incubation of CCA wood dust in cell culture media resulted in the transfer of copper, but not chromium or arsenic, into the media. Moreover, the treatment of cells with this filtered extract resulted in significantly increased metallothionein mRNA, suggesting that bioavailable copper is responsible for inducing metallothionein mRNA in V79 cells. Thus, these bioassays suggest that metals become bioavailable during in vitro culture of phagocytic V79 cells with CCA wood dust.

Animals↗
PubMed2004

Multicenter, double-blind, randomized comparison of wood creosote, the principal active ingredient of Seirogan, an herbal antidiarrheal medication, and loperamide in adults with acute nonspecific diarrhea.

BACKGROUND: Seirogan, an herbal medication containing wood creosote, a mixture of simple phenolic (single-ring)compounds, has been marketed in Asia for the past century as an antidiarrheal and antispasmodic medication. This was the first randomized, double-blind study of this herbal medication in patients with acute, nonspecific diarrhea. OBJECTIVE: The aim of this study was to compare the efficacy and tolerability of wood creosote with those of loperamide hydrochloride in patients with acute, nonspecific diarrhea. METHODS: This double-blind, randomized, active-controlled study was conducted at 12 centers across the United States and Mexico. Patients aged >or=18 years with acute, nonspecific diarrhea, defined as a history of diarrhea for or=3 unformed stools in the 24 hours before the study, accompanied by >or=1 associated symptom (ie, nausea, vomiting, abdominal cramping, and/or fever [<or=101.0 degrees F or <or=38.3 degrees C]), were eligible for the study Patients received wood creosote 135 mg (<or=5 doses/d) or loperamide 4 mg (loading dose) followed by 2 mg (<or=8 mg/d) after each loose stool for <or=3 days. The primary efficacy end point was the time to the last unformed stool (TTLUS). Clinical safety laboratory tests and patient diaries were used to assess tolerability. RESULTS: One hundred twenty-three patients (74 women, 49 men; mean [SD] age, 42.6 [14.9] years; age range, 18-90 years) were randomized to receive wood creosote (n = 60) or loperamide (n = 63). Eighty-four of the 123 enrolled patients (68.3%) were Hispanic, 18 (14.6%) white, 17 (13.8%) black, and 4 (3.3%) Asian or Pacific Islander. The majority of patients (88.3% in the wood creosote group and 95.2% in the loperamide group) had abdominal cramping as the predominant associated symptom. The median (interquartile range [IQR]) TTLUS was similar between groups (24.4 [6.3-36.8] and 22.1 [3.5-32.1] hours in the wood creosote and loperamide groups, respectively), as was the median (IQR) time to total relief (31.0 [15.7-47.8] and 28.5 [13.5-43.5] hours in the wood creosote and loperamide groups, respectively). The mean (SD) numbers of unformed stools on day 1 were 3.31 (2.15) and 2.22 (1.25) in the wood creosote and loperamide groups, respectively (P < 0.002). The percentages of patients with improved or resolved abdominal cramping at the end of day 1 were 92.5% (49/53) and 78.0% (46/59) in the wood creosote and loperamide groups, respectively (P < 0.038). Both medications were well tolerated in the population studied. CONCLUSIONS: Wood creosote and loperamide had comparable antidiarrheal effects in these patients with acute, nonspecific diarrhea. Wood creosote appeared somewhat more efficacious in improving or resolving abdominal cramping, whereas loperamide appeared somewhat more efficacious in improving diarrhea. Both treatments were well tolerated.

Adolescent↗