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PubMedDate not supplied

Urinary arsenic, chromium, and copper levels in workers exposed to arsenic-based wood preservatives.

Urinary excretion of arsenic, chromium, and copper in workers exposed to arsenic-based wood preservatives was examined to evaluate occupational exposure to these chemicals. Spot urine samples were collected from 89 wood treaters and a comparison group of 232 individuals with no known exposure to arsenicals. The results of urinalysis revealed that the wood treaters averaged 103 micrograms arsenic/L while the comparison group averaged 74 micrograms arsenic/L. The mean urinary chromium and copper levels of the wood treaters were 41 micrograms chromium/L and 191 micrograms copper/L compared with 63 micrograms chromium/L and 221 micrograms copper/L for the comparison group. Covariance analysis of urinary arsenic level between the exposed and comparison groups revealed that the adjusted mean arsenic levels of the exposed population (78 to 122 micrograms arsenic/L) were significantly higher than that of the comparison group (72 micrograms arsenic/L). The adjusted mean urinary arsenic levels of these wood treaters, however, were within published normal limits. Analysis of covariance allowed comparison of group means after statistical adjustments for possible confounding variables such as seafood intake and age. The results indicate that urinary arsenic values can provide a useful index of occupational exposure to chromated copper arsenate wood preservatives, when the effects of dietary arsenic are controlled statistically.

Adult↗
PubMed1990

Mouse skin tumorigenicity studies of indoor coal and wood combustion emissions from homes of residents in Xuan Wei, China with high lung cancer mortality.

The rural Xuan Wei County, Yunnan Province, China, has an unusually high lung cancer mortality rate that cannot be attributed to tobacco smoke or occupational exposure. The lung cancer rate is associated with 'smoky' coal, in contrast to wood or 'smokeless' coal burned in unventilated homes. This study was conducted to characterize and compare mouse skin tumorigenicity of the coal and the wood combustion emissions and to link the animal data to human lung cancer. Indoor air particles (less than 10 microns) were collected from a central commune where the lung cancer mortality rate is high and smoky coal is the major fuel used and also from a south-western commune where lung cancer mortality rate is low and where wood or smokeless coal are the major fuels used. The organic extracts of these indoor air particles from smoky coal, smokeless coal and wood combustion were analysed for polycyclic aromatic hydrocarbons and assayed for skin tumor initiation activity and complete carcinogenicity in SENCAR mice. The results showed that the organic extract of the emission particles from smoky coal combustion is the most active in tumor initiation among the three combustion emission samples followed by smokeless coal and then wood. The organic extract of the particles from smoky coal combustion was shown to be a potent complete carcinogen, whereas the wood extract was relatively inactive as a complete carcinogen. The extract of particles from the smokeless coal combustion was not tested for complete carcinogenicity because of inadequate supply. Eighty-eight percent of the mice treated with the smoky coal extract showed carcinomas, averaging 1.1 carcinomas per tumor-bearing mouse at the end of the 77 week study. These findings were in agreement with the epidemiological data, which showed that the Xuan Wei residents using smoky coal as a major fuel in homes had a high lung cancer mortality rate. This study demonstrates that the results of the tumorigenicity assays in mice were in agreement with human lung cancer data.

Air Pollutants↗
PubMed2002

Successional changes in live and dead wood carbon stores: implications for net ecosystem productivity.

If forests are to be used in CO2 mitigation projects, it is essential to understand and quantify the impacts of disturbance on net ecosystem productivity (NEP; i.e., the change in ecosystem carbon (C) storage with time). We examined the influence of live tree and coarse woody debris (CWD) on NEP during secondary succession based on data collected along a 500-year chronosequence on the Wind River Ranger District, Washington. We developed a simple statistical model of live and dead wood accumulation and decomposition to predict changes in the woody component of NEP, which we call NEP(w). The transition from negative to positive NEP(w), for a series of scenarios in which none to all wood was left after disturbance, occurred between 0 and 57 years after disturbance. The timing of this transition decreased as live-tree growth rates increased, and increased as CWD left after disturbance increased. Maximum and minimum NEP(w) for all scenarios were 3.9 and -14.1 Mg C ha-1 year-1, respectively. Maximum live and total wood C stores of 319 and 393 Mg C ha(-1), respectively, were reached approximately 200 years after disturbance. Decomposition rates (k) of CWD ranged between 0.013 and 0.043 year-1 for individual stands. Regenerating stands took 41 years to attain a mean live wood mass equivalent to the mean mass of CWD left behind after logging, 40 years to equal the mean CWD mass in 500-year-old forest, and more than 150 years to equal the mean total live and dead wood in an old-growth stand. At a rotation age of 80 years, regenerating stands stored approximately half the wood C of the remaining nearby old-growth forests (predominant age 500 years), indicating that conversion of old-growth forests to younger managed forests results in a significant net release of C to the atmosphere.

Biomass↗
PubMed2006

Multiplex real-time PCR detection of pathogen colonization in the bark and wood of Picea sitchensis clones differing in resistance to Heterobasidion annosum.

A quantitative multiplex real-time polymerase chain reaction (PCR) procedure was developed to assess the extent of Heterobasidion annosum (Fr.) Bref. growth in Sitka spruce (Picea sitchensis (Bong.) Carr.) bark and wood and to determine correlations between lesion length and fungal colonization. Based on lesion length and real-time PCR, the responses of four 3-year-old Sitka spruce clones to inoculation with H. annosum were characterized as showing either resistance or susceptibility to the pathogen. In susceptible clones, the extent of bark colonization did not differ from the visible length of the bark lesion, whereas lesions were longer than the extent of fungal colonization in resistant clones. The resistant clones contained considerably less fungal DNA than the susceptible clones, relative to the amount of host DNA in both the bark and the wood, indicating less resistance and more host cell death in the susceptible clones following inoculation. In both resistant and susceptible clones, fungal colonization in the wood extended beyond the visible necrotic lesion in the bark, indicating that host defense responses are weaker in wood than in bark. The spread of the pathogen in both bark and wood was less in the resistant clones than in the susceptible clones, indicating that defenses in both bark and wood of the resistant clones were superior to those in the susceptible clones.

Agaricales↗
PubMed2002

Batting performance of wood and metal baseball bats.

INTRODUCTION/PURPOSE: Although metal baseball bats are widely believed to outperform wood bats, there are few scientific studies which support this. In a batting cage study, Greenwald et al. found that baseballs hit with a metal bat traveled faster than those hit with a wood bat, but the factors responsible for this difference in bat performance remain unidentified. The purpose of this study was to determine the effects of swing speed, impact location, and elastic properties of the bat on batted ball speeds. METHODS: The pitched ball, batted ball, and swings of two wood and five metal baseball bats by 19 different players were tracked in three dimensions at 500 Hz using a passive infrared motion analysis system. RESULTS: Increases in the batted ball speeds of metal bats over those of wood bats resulted from faster swing speeds and higher elastic performance with an apparent increase in the ball-bat coefficient of restitution. The contribution of these variables to batted ball speed differed with metal bat model. The "sweet spot" associated with maximum batted ball speeds was located approximately the same distance from the tip of wood bats as it was from metal bats. CONCLUSIONS: The variables that correlated with differences between metal and wood bat performance, and most notably differences in the percentage of faster batted balls, were identified using a novel kinematic analysis of the ball and bat. These variables and their correlation with bat performance should be applicable to other players and bats, although more skilled players and higher performing bats would likely result in even faster batted ball speeds.

Acceleration↗
PubMed1997

Wood dust and nasal cancer risk. A review of the evidence from North America.

In this article, biomedical literature assessing risks of nasal cancer and nonmalignant nasal pathology among woodworkers in North America is reviewed in detail and contrasted with experience from Europe and elsewhere. Exceptionally high rates of nasal adenocarcinoma have occurred among European hardwood furniture workers, but the epidemiologic evidence documents a disparity in findings between North America and Europe. Cohort studies of American wood-dust-exposed groups do not reveal excesses of nasal cancer, and wood-dust associations from US and Canadian case-control studies of nasal cancer tend not to be strong and differ across studies. Quantitative wood-dust exposure data are generally unavailable, but general dose information in European studies suggests that the excess risk of nasal cancer is associated with high levels of exposure. There is also an inconsistent association between wood-dust exposure per se and mucostasis or nasal histologic changes, and the mucostasis/metaplasia/dysplasia route to nasal cancer is still an unverified hypothesis. Considering the totality of evidence on the risk of cancer in exposed workers, it appears that wood-dust-related nasal adenocarcinoma essentially can be eliminated in Europe and its occurrence prevented in the United States if wood-dust exposures do not exceed an 8-hour time-weighted average 5 mg/m3 standard.

Adenocarcinoma↗
PubMed1997

Occupational asthma and rhinitis caused by ash (Fraxinus excelsior) wood dust.

An 18-year-old man who worked in a furniture factory reported rhinitis and asthma when he was exposed to ash wood dust. Monitoring of the patient's peak expiratory flow rate (PEFR) when off work and at work showed increased variations of PEFR at work. Basal PC20 methacholine was 1.41 mg/ml. A bronchial provocation test (BPT) with a 1:1000 w/v ash wood dust extract induced a dual asthmatic response with a 7.5-fold increase of nonspecific bronchial responsiveness. Intradermal testing with ash wood extract elicited a positive immediate response. IgE antibodies against ash wood were found in the patient's serum with a RAST value of 0.57 PRU/ ml. Similar skin tests, BPT, and RAST with ash wood dust performed in control patients were all negative. All the studies performed suggest that our patient had occupational rhinitis and asthma caused by exposure to ash wood dust in which a type I immunologic mechanism was implicated.

Adolescent↗
PubMed2005

Transcript profiling of Eucalyptus xylem genes during tension wood formation.

Tension wood formed in response to gravitational force is a striking example of the plasticity of angiosperm wood. In this study our goal was to characterize the early changes in gene expression during tension wood formation in Eucalyptus. Using cDNA array technology, transcript profiling of 231 genes preferentially expressed in differentiating Eucalyptus xylem was followed from 6 h to 1 wk of a tension time course of artificially bent Eucalyptus trees. 196 genes were differentially regulated between control and bent trees, some exhibiting distinctive expression patterns related to changes in secondary cell wall structure and composition. For instance, expression of a cellulose synthase gene was well correlated with the appearance of the G-layers. Cluster correlation analysis revealed differential regulation of lignin biosynthetic genes and may also be used to help infer the function of unknown gene products. Eucalyptus wood transcriptome analysis during tension wood formation not only provided new clues into the transcriptional regulatory network of genes preferentially expressed in xylem, but also highlighted candidate genes responsible for the genetic and environmentally induced variation of wood quality traits.

Biomechanical Phenomena↗
PubMed2002

Use of NIR and pyrolysis-MBMS coupled with multivariate analysis for detecting the chemical changes associated with brown-rot biodegradation of spruce wood.

Near infrared (NIR) spectroscopy and pyrolysis-molecular beam mass spectrometry (py-MBMS) analysis can be used in conjunction with multivariate regression and principal components analysis to differentiate brown-rot-degraded wood from non-degraded spruce and to follow the temporal changes in wood undergoing brown-rot degradation. Regression of NIR test results vs. percent weight loss for Postia placenta- and Gloeophyllum trabeum-infected spruce wood blocks yielded a correlation coefficient of 0.96. Regression of MBMS test results for the same samples yielded a correlation coefficient of 0.96. Principle components analysis was used to differentiate non-infected wood and P. placenta- and G. trabeum-infected wood. These techniques may be used to detect different types of biodegradation and to develop a better understanding of the chemical changes that the wood undergoes when it is subjected to brown-rot biodegradation.

Biodegradation, Environmental↗
PubMed2000

Bacterial biodegradation of extractives and patterns of bordered pit membrane attack in pine wood.

Wood extractives, commonly referred to as pitch, cause major problems in the manufacturing of pulp and paper. Treatment of nonsterile southern yellow pine chips for 14 days with Pseudomonas fluorescens, Pseudomonas sp., Xanthomonas campestris, and Serratia marcescens reduced wood extractives by as much as 40%. Control treatments receiving only water lost 11% of extractives due to the growth of naturally occurring microorganisms. Control treatments were visually discolored after the 14-day incubation, whereas bacterium-treated wood chips were free of dark staining. Investigations using P. fluorescens NRRL B21432 showed that all individual resin and fatty acid components of the pine wood extractives were substantially reduced. Micromorphological observations showed that bacteria were able to colonize resin canals, ray parenchyma cells, and tracheids. Tracheid pit membranes within bordered pit chambers were degraded after treatment with P. fluorescens NRRL B21432. P. fluorescens and the other bacteria tested appear to have the potential for biological processing to substantially reduce wood extractives in pine wood chips prior to the paper making process so that problems associated with pitch in pulp mills can be controlled.

Bacteria↗
PubMed2000

Protective and defensive airway reflexes evoked by nasal exposure to wood smoke in anesthetized rats.

We investigated the airway responses evoked by nasal wood smoke in anesthetized Sprague-Dawley rats. Wood smoke (5 ml, 1.4 ml/s) was delivered into an isolated nasal cavity while animals breathed spontaneously. In study 1, nasal wood smoke triggered either an apneic response (n = 26) or a sniff-like response (n = 16) within 1 s after smoke exposure in 42 normal rats. Both airway responses were abolished by trigeminal nerve denervation and by nasal application of a local anesthetic or a hydroxyl radical scavenger, but they were not significantly affected by removal of smoke particulates or nasal application of a saline vehicle. In study 2, nasal wood smoke only triggered a mild apneic response in two rats neonatally treated with capsaicin and had no effect on breathing in the other six; the treatment is known to chronically ablate C fibers and some Adelta fibers. In contrast, nasal wood smoke evoked an apneic response in six rats neonatally treated with the vehicle of capsaicin and elicited a sniff-like response in the other two. These results suggest that the apneic and sniff-like responses evoked by nasal wood smoke result from the stimulation of trigeminal nasal C-fiber and Adelta-fiber afferents by the gas-phase smoke and that hydroxyl radical is the triggering chemical factor.

Animals↗
PubMed2001

In vitro effects of wood creosote on enterotoxin-induced secretion measured electrophysiologically in the rat jejunum and colon.

Secretory diarrhea occurs when the balance between intestinal absorption and secretion is disturbed by excessive secretion caused by enterotoxins produced by the pathogen. Wood creosote has long been used as a traditional antidiarrheal remedy. The goal of our study was to extend our knowledge about the antisecretory action of wood creosote against Escherichia coli enterotoxin-induced secretion in the small intestine and colon. Experiments were performed in mucosal sheets of rat jejunum and colon which were stripped of the external muscle layers to eliminate interactions with smooth muscle activity and local blood flow. Mucosal sheets were placed in modified Ussing chambers and hypersecretory conditions were induced by heat-labile (LT) or heat-stable (STa) E. coli enterotoxins added cumulatively (0.01-10 microg/ml) to the mucosal bathing solution. Intestinal secretion was monitored electrophysiologically as transmucosal short circuit current (Isc). LT induced a concentration-dependent increase in Isc in the rat jejunum, with no effect in the colon. In contrast, STa induced a significant increase in colonic Isc, without causing any change in Isc across the jejunum. In separate experiments the effects of increasing concentrations of wood creosote (0.1-50 microg/ml), added to the mucosal or serosal bathing solution, were examined against the secretory responses induced by LT or STa. In the small intestine the antisecretory activity of wood creosote against LT-induced secretion was more potent following serosal application, whereas in the colon wood creosote inhibited STa-induced secretion with equal potency following either serosal or mucosal addition. In summary, our findings demonstrate that wood creosote possesses antidiarrheal activity suppressing E. coli enterotoxin-induced secretion in both the small intestine and colon.

Animals↗
PubMed2005

Methyl bromide as a quarantine treatment for Anoplophora glabripennis (Coleoptera: Cerambycidae) in regulated wood packing material.

Anoplophora glabripennis (Motschulsky), has recently (since 1996) established in limited infestations near several cities in the United States. A. glabripennis was probably introduced into the United States with solid wood packing or dunnage. During 2001, we evaluated the current APHIS Schedule T404-b-1-1 for methyl bromide (MeBr) fumigation. Fumigations were conducted in 432-liter Lexan chambers inside a 6.1-m refrigerated container. Each fumigation consisted of 12 high-moisture, naturally infested Populus spp. timbers. We fumigated wood for 24 h at 4.4 degrees C (80 g/m3), 10.0 degrees C (64 g/m3), 15.6 degrees C (56 g/m3), and 21.1 degrees C (48 g/m3). All schedule doses resulted in 100% kill of A. glabripennis larvae. During 2002, we conducted additional fumigations to determine the basic toxicity of MeBr to A. glabripennis larvae in solid wood timbers of 10 by 10 by 115-cm size. Probit analysis estimated the CxT product at 99.0, 99.9, 99.99, and 99.99683% kill (probit-9). The probit-9 values for CxT were 1,196.1, 918.7, 642.4, and 362.4 g-h/m3 at 4.4, 10.0, 15.6, and 21.1 degrees C, respectively. Applied doses to achieve this level of control were estimated to be 119.6, 82.7, 56.0, and 32.2 g/m3, respectively. These applied doses are satisfactory for wood as a commodity with wood load factors of approximately 25% and may be higher than necessary for container fumigation where sorptive wood load as crating or pallets may only be 5% or less. The APHIS Schedule T404-b-1-1 is adequate if extended for 24 h and should be amended to include intermediate doses at 10.0 and 15.6 degrees C, thus reducing the use of MeBr at these temperatures.

Animals↗
PubMedDate not supplied

Arsenic availability from chromated copper arsenate (CCA)-treated wood.

Lumber used to construct raised garden beds is often treated with chromated copper arsenate (CCA). This project aimed to determine (i) how far As, Cu, and Cr had diffused away from CCA-treated wood surfaces in raised garden beds under realistic conditions, (ii) the uptake of these elements by crops, and (iii) the effect of CCA solution on soil bacteria. This study showed that As, Cu, and Cr diffuse into soil from CCA-treated wood used to construct raised garden beds. To determine crop uptake of these elements, contaminated soil 0 to 2 cm from the treated wood was obtained from two different beds (40-50 mg kg(-1) As); control soil was collected 1.5 m away from the treated wood (<3-10 mg kg(-1) As). Four replicates of carrot (Daucus carota var. sativus Hoffm. cv. Thumbelina), spinach (Spinacia oleracea L. cv. Indian Summer), bush bean (Phaseolus vulgaris L. cv. Provider), and buckwheat (Fagopyrum esculentum Moench cv. Common) were grown in pots containing these soils in a greenhouse. After harvest, plant materials were dried, ground, digested, and analyzed for As by inductively coupled plasma-hydride generation (ICP-HG). Concentrations of As in all crops grown in contaminated soils were higher than those from control soils. The levels of As in the crops remained well below the recommended limit for As set by the United States Public Health Service (2.6 mg kg(-1) fresh wt.). To determine if bacteria in soils 0 to 2 cm from the treated wood had higher resistance to Type C chromated copper arsenate (CCA-C) solution than those from reference soils, dilution plates were set up using quarter-strength tryptic soy agar (TSA) media and 0 to 22.94 g L(-1) (0-1.25% v/v) CCA-C working solution. The microorganisms from soils adjacent to treated wood had greater growth on the CCA-amended media than those from reference soils outside the bed.

Arsenates↗
PubMed2006

A novel extractant for removal of hazardous metals from preservative-treated wood waste.

The purpose of this study was to develop a one-step metal extraction process that would effectively remove hazardous elements from wood powder or chips of western hemlock [Tsuga heterophylla (Raf.) Sarg.] treated with chromated copper arsenate (CCA) preservative. In addition, we tested this method for wood treated with other copper-based preservatives such as ammoniacal copper quaternary (ACQ) and copper, boron, and azole (CuAz). A bioxalate solution consisting of 0.125 M oxalic acid adjusted to pH 3.2 with sodium hydroxide was tested for its ability to extract chromium, copper, and arsenic from wood treated with CCA and copper from ACQ, CuAz, or a mixture of CCA-, ACQ-, and CuAz-treated wood in single step. The extraction proceeded efficiently with 6 h of treatment, and was insensitive to the differences in chemical characteristics, including solubility of individual elements. After 6 h of treatment, approximately 90% of chromium, copper, and arsenic were effectively removed from wood treated with CCA or a mixture of CCA, ACQ, and CuAz and 90% of copper from ACQ- and CuAz-treated wood. These results demonstrate that the solvent extraction technique using pH-adjusted bioxalate solution with sodium hydroxide is a promising method for pollution minimization by various types of wastes contaminated with heavy metals and arsenic.

Metals↗
PubMedDate not supplied

Histological changes in the nasal mucosa in rats after long-term exposure to formaldehyde and wood dust.

Wood dust is a well known nasal carcinogen in man, as formaldehyde is in rats. In certain occupational environments, combined exposure to wood dust and formaldehyde is common. Little is known about the effects of this combination. A pilot study was performed on four groups of Sprague-Dawley rats: one exposed to wood dust (25 mg/m3), another to formaldehyde (12.4 ppm) and a third to both wood dust and formaldehyde; the fourth group served a control group. After 104 weeks of exposure the nose and lungs were examined histologically. One well differentiated squamous cell carcinoma was found in the formaldehyde group. Squamous cell metaplasia was found significantly more often among the formaldehyde-exposed rats. Squamous cell metaplasia with dysplasia was most frequently observed, however, in the group exposed to both formaldehyde and wood dust. There were also significantly more rats with pulmonary emphysema in the groups exposed to wood dust than in the other groups.

Animals↗
PubMed1998

A survey into process and worker's characteristics in the wood furniture industry in Songkhla Province, southern region of Thailand.

A cross-sectional survey of the wood furniture industry was conducted in southern Thailand in February 1993. The aim was to examine the manufacturing process, occupational hazards at the workplace, workers' demographic characteristics, period of employment, incidence rate of work related injury and some reproductive history of workers. Altogether 69 managers and 1,000 workers participated in the study. There are 2 main types of wood industry, rubberwood and hardwood. The rubberwood industry is semi-automated with advanced technology, has a female-dominated workforce of 200-300 workers per factory and overseas-market orientation. The hardwood industry is based in small-scale workplaces ranging from 20 to 60 workers, domestic-market orientation and has a male-dominated workforce. Most of the workers were young, single, of low education and were high turnover rate laborforce, with arduous work and long working hours per week. Solvent was the most frequent chemical exposure. The person-year incidence of chemical exposure in female workers was higher than in male workers for every group of chemicals. The incidence of accidents was twice as high as the official rate. The standardized fertility ratio of female wood workers was only 51.6% of that of the Thai female population. There was a high abortion rate among women who became pregnant inside the wood industry compared to that among pregnancies outside the wood factory. Wood industry workers were exposed to occupational hazards and accident-prone work conditions.

Accidents, Occupational↗
PubMed2000

[Biodegradation of Venezuelan woods in field stake tests in the western lowlands].

Following known standards, a Field Test Site was established in Bum Bum area, located in Ticoporo Forest Reserve, tropical dry forest, Barinas State, Venezuela, for the study of wood biodegradation. Wood stakes from various wood species particularly Caribbean pine, with 500 mm x 50 mm x 25 mm in dimensions, were treated with several chemicals and concentrations and were installed in natural soil together non treated wood samples. Results concerning natural and induced durability are discussed; observations in Caribbean pine wood showed that the termite attack was responsible for failure of all non treated stakes and some samples treated with triazoles. Together Soft rot Type I and Tunnelling bacterial attack, termites are the main wood biodegradation agents.

Animals↗