Characterization of Airborne Particulates and Worker Exposures in Electro-static Powder Coating Operations.

This study was to examine the airborne particulates/dusts and worker exposures in electro-static powder coating operations. Temporal variation and size distribution of dusts were assessed using direct-reading instrument, while the worker task-specific dust exposures (n = 41) were measured in three factories using conventional filter method. Additionally, toxic metal levels in the coating powder (n = 27) were analyzed to assess hazard potentials. Continuous monitoring of airborne respirable dust levels indicated large temporal variation across a normal working day. The particulate levels outside spraying booths were generally low (below 0.10 mg m-3) during normal spraying operation, but short-term level may reach as high as 21.8 mg m-3 (averaged at 4-5 mg m-3) when specific task such as cleaning the pipelines and spraying booth, was performed. Exploratory assessment on particle size distribution at four major working zones, administration, uploading, spraying, and baking, indicated no major difference among the zones, and between factories. The particle count median aerodynamic diameter was 0.88-1.69 µm, while the mean number concentrations were 10.97, 15.17, 18.49, and 27.03 (# cm-3) for zones administration, uploading, spraying, and baking, respectively. The worker task-specific dust exposures were found low during normal spraying, with the mean short-term total and respirable dust concentrations being 0.88 and 0.41 mg m-3, respectively. Both levels increased to 3.48 and 5.19 mg m-3, respectively (P < 0.05), if powder changing and system cleaning were done. Short-term total and respirable dust concentrations were 94.2 and 56.1 mg m-3, respectively, when complete cleaning process was performed inside spraying booth. Both levels exceeded the short-term exposure limits. The mean concentration of metals in the powder samples were 6.78, 9.52, 10 717, 2805, 1020, and 1361 µg g-1 for Pb, Cr (total), Al, Fe, Cu, and Sr, respectively. This study demonstrated that cleaning of spraying booth resulted in high dust exposures well exceeding the exposure limit. Toxic metals, particularly Pb, Cd, and Cr (total), levels measured in the powder samples were found low, and the resulting exposures were below the exposure limits, indicating relative low risks associated with the exposure at current dust levels.

Water-Based Automobile Paints Potentially Reduce the Exposure of Refinish Painters to Toxic Metals.

Exposure to lead-containing dusts is a global public health concern. This work addresses an important issue of whether eco-friendly water-based paints reduce the exposure potential of auto-repainting workers to metals. With this aim, metal levels in automobile paints and worker metal exposure were measured using both solvent- and water-based paints. The levels of metals, and particularly Pb, Cr (total), Fe, and Cu, in solvent-based paints varied greatly among colors and brands. Lead concentrations ranged from below the detection limit (~0.25 μg/g) to 107,928 μg/g (dry film) across all samples. In water-based paints, the concentrations of Pb and Cr (total) were generally two to three orders of magnitude lower, but the concentrations of Al and Cu exceeded those in some solvent-based paints. The personal short-term exposure of workers who applied water-based paints of popular colors, such as black and white, were generally low, with Pb levels of less than <4 µg/m³ and Cr (total) levels of less than 1 µg/m³. Conversely, mean short-term exposure to Pb during the painting of a yellow cab using solvent-based paints were 2028 µg/m³, which was ~14 times the Taiwan short-term permissible exposure limit, while the mean level of exposure to Cr (total) was 290 µg/m³, which was well below the exposure limit. This study demonstrates that water-based paints reduce the exposure potential to lead, and highlights the importance of source control in limiting the toxic metals in paints.

Essential and toxic metals in animal bone broths.

Background: This investigation examines the extraction of metals from animal bones into broth, and assesses whether bone broths are good sources of essential metals and the risks associated with the consumption of toxic metals. Method:Three sets of controlled experiments were performed to study the factors (cooking time, acidity, bone type and animal species) that influence metal extractions. Three types of animal bone broth-based foods were also tested. Results: Reducing the broth pH from 8.38 to 5.32 significantly (p < 0.05) increased Ca and Mg extraction by factors of 17.4 and 15.3, respectively. A long cooking time, > 8 h, yielded significantly higher (p < 0.05) Ca and Mg extraction than shorter cooking times. The extraction characteristics of metals, particularly Ca, Mg, Cu and Al, from the leg and rib bones differed. The between-species variations in extraction were larger than those of within-species. Conclusions:The Ca and Mg levels in home-made or commercial broth/soup were found not to exceed low tenths of milligram per serving, or <5% of the daily recommended levels. The risks that are associated with the ingestion of heavy metals such as Pb and Cd in broth are minimal because the levels were in the ranges of a few µg per serving.

Excretion kinetics of urinary 3-hydroxybenzo[a]pyrene following dietary exposure to benzo[a]pyrene in humans.

Urinary 3-hydroxy-benzo[a]pyrene (3-OHBaP) is considered as an exposure marker for assessing carcinogenic risks as it is a metabolite of benzo[a]pyrene (BaP). A controlled human study was conducted to examine the kinetics of urinary 3-OHBaP after consuming charcoal-barbecued meat. Two feeding experiments were performed, with meat doses of 15 and 30 g/kg (experiments 1 and 2, respectively). All voided urine over 7 days was collected and analyzed. The background urinary 3-OHBaP concentration was 0.002-0.085 ng/g creatinine, with large inter-individual (80-100%) and intra-individual of (90-100%) variations. The background amount of 3-OHBaP excreted by the current subjects was 40-50 pg/day. The amounts of urinary 3-OHBaP excreted within 12 h post-exposure increased significantly (P < 0.05) from background only in experiment 1. The proportion of the administered BaP dose that was excreted as urinary 3-OHBaP within 12 h post-exposure was 0.006 and 0.0012% in experiments 1 and 2, respectively. The excretion ratio declined as the dose increased. Urinary 3-OHBaP can be used to assess dietary exposure to BaP, but it may be not suitable for low-dose scenarios because of the low urinary excretion proportion and high variability of the background.

Characteristics of microbial aerosols released from chicken and swine feces.

Bioaerosols generated during livestock and poultry production are significant occupational hazards. This study investigates the characteristics of bioaerosols released from animal feces. Fresh feces from pigs and chickens were obtained and tested in a controlled-environment facility. Airborne viable (culturable) bacteria and fungi were sampled hourly for 48 hr. The predominant species were identified via polymerase chain reaction analysis. The number of bacterial colonies released from chicken feces increased gradually, peaked at approximately 20 hr, and remained relatively constant to test end; however, the bacterial colonies released from swine feces did not increase significantly. The chicken feces released significantly (P < 0.05) more bacterial aerosols than swine feces over 40 hr, by approximately 1 order of magnitude. However, the difference in total fungal aerosols released from the two feces types was relatively small (30-40%) and insignificant (P > 0.05). Aerosols sized between approximately 0.65 and 1.1 microm were predominant for bacteria, whereas aerosols sized between approximately 2.1 and 3.3 microm prevailed for fungi. Genera Stenotrophomonas were the predominant bacterial aerosols, whereas Cladosporium and Acremonium accounted for the greatest amounts of fungi from chicken and swine feces, respectively. More than 1000 culturable bacterial colonies can be released from 1 g of chicken feces per hour, and approximately 80% of these bioaerosols are respirable. Most bacterial aerosols released from swine and chicken feces were opportunistic human pathogens; thus, the significance of their presence warrants further investigations.

Volatile organics off-gassed among tobacco-exposed clothing fabrics.

This work evaluates the characteristics of short-term release of volatile and semi-volatile organic chemicals from clothing fabrics that are exposed to environmental tobacco smoke (ETS). Various fabrics were concurrently exposed to ETS in a controlled facility, and the chemicals off-gassed were sampled using solid phase micro-extraction coupled with GC/MS analysis. Toluene-reference concentration (TRC) was calculated for nine selected chemicals and compared. The number of chemicals identified from ETS-exposed fabrics ranged from 13 (polyester and acetate) to 32 (linen). All fabrics off-gassed formaldehyde, tetradecanoic acid and n-hexadecanoic acid, while seven out of eight fabrics emitted furfural, benzonitrile, naphthalene and decanal. Natural fibers of plant origin (cotton and linen) off-gassed higher concentrations (TRC>100 µg/l) of chemicals that have low molecular weight (~100 or less) than did natural fibers of animal origin (wool and silk) and synthetic fibers. Conversely, wool and silk off-gassed more chemicals that are of high molecular weight (>200), such as TDA (TRC>100 µg/l) and n-HDA (TRC>500 µg/l), than did other fabrics. Fabric structure (for a particular material) significantly affects chemical off-gassing. Cotton typically used for polo shirt (knitted) off-gassed significantly (p<0.05) higher TRC for chemicals with molecular weight of ~100 (such as furfural) than did other cottons of woven style. The dyeing of fabric (white vs. black) had a limited effect on emission, while increasing contact time with ETS increased the intensity of chemical emissions. The mean TRC for cotton exposed for 12 min was nearly doubled than those exposed for 8min, but no difference existed for polyester.

Comparative analysis of urinary N7-(2-hydroxyethyl)guanine for ethylene oxide- and non-exposed workers.

Ethylene oxide (EO), a direct alkylating agent and a carcinogen, can attack the nucleophilic sites of DNA bases to form a variety of DNA adducts. The most abundant adduct, N7-(2-hydroxyethyl)guanine (N7-HEG), can be depurinated spontaneously or enzymatically from DNA backbone to form abasic sites. Molecular dosimetry of the excised N7-HEG in urine can serve as an EO exposure and potential risk-associated biomarker. This study was to analyze N7-HEG in urine collected from 89 EO-exposed and 48 nonexposed hospital workers and 20 exposed and 10 nonexposed factory workers by using our newly developed on-line solid-phase extraction isotope-dilution LC-MS/MS method. Statistical analysis of data shows that the exposed factory workers excreted significantly greater concentrations of N7-HEG than both the nonexposed factory workers and hospital workers. Multiple linear regression analysis reveals that the EO-exposed factory workers had a significantly greater post-shift urinary N7-HEG than their nonexposed coworkers and hospital workers. These results demonstrate that analysis of urinary N7-HEG can serve as a biomarker of EO exposure for future molecular epidemiology studies to better understand the role of the EO-induced DNA adduct formation in EO carcinogenicity and certainly for routine surveillance of occupational EO exposure for the study of potential health impacts on workers.

Amounts and proportion of administered pyrene dose excreted as urinary 1-hydroxypyrene after dietary exposure to polycyclic aromatic hydrocarbons.

Although urinary 1-hydroxypyrene (1-OHP) is the most relevant parameter for assessing exposure to polycyclic aromatic hydrocarbons, the inability to further elucidate the intra- and inter-individual variability, specificity and kinetics makes it difficult to enhance its value as an exposure predictor. Therefore, this human control study examined the excretion kinetics of urinary 1-OHP after consuming barbecued meat. Two feeding experiments were conducted, with doses of 15 and 30 g of barbecued meat per kg of body weight for experiments 1 and 2, respectively. All voided urine was collected for 7 days and analyzed for 1-OHP. In both experiments, the amounts of urinary 1-OHP excreted was significantly increased (P < 0.05) at 12 h post exposure but not at 12-24 h post exposure. Mean percentages of administered pyrene doses excreted as urinary 1-OHP at 0-12 h and 12-24 h post exposure were 3.80 and 0.61% in experiment 1 and 1.66 and 0.38% in experiment 2. Excretion ratio was inversely related to dose. A pattern of diurnal fluctuation (P < 0.05) in 1-OHP excretions was also identified. That is, 1-OHP excretions were smaller in the first half of the day (~0:00-12:00) than in the last half of the day (~12:00-24:00). This study demonstrated that, even at large dietary doses, most of the total urinary excretion of 1-OHP occurs within 12 h. Thus, subjects of occupational or environmental studies need only recall their diets for the current or previous day to diminish the influence from dietary pyrene.

Bayesian analysis of a physiologically based pharmacokinetic model for perchloroethylene in humans.

Perchloroethylene (PCE) is a widely distributed pollutant in the environment, and is the primary chemical used in dry cleaning. PCE-induced liver cancer was observed in mice, and central nervous system (CNS) effects were reported in dry-cleaning workers. To support reconstruction of human PCE exposures, including the potential for CNS effects, an existing physiologically based pharmacokinetic (PBPK) model for PCE in the human (Covington et al., 2007) was modified by adding a brain compartment. A Bayesian approach, using Markov chain Monte Carlo (MCMC) analysis, was employed to re-estimate the parameters in the modified model by combining information from prior distributions for the model parameters and experimental data. Experimental data were obtained from five different human pharmacokinetic studies of PCE inhalation exposures ranging from 150 ppm to as low as 0.495 ppm. The data include alveolar or exhaled breath concentrations of PCE, blood concentrations of PCE and trichloroacetic acid (TCA), and urinary excretion of TCA. The PBPK model was used to predict target tissue dosimetry of PCE and its key metabolite, TCA, during and after the inhalation exposures. Posterior analysis was performed to see whether convergence criteria for each parameter were satisfied and whether the model with posterior distributions may be used to make accurate predictions of human kinetic data. With posteriors, the trend of percent of PCE metabolized in the liver at low concentrations was predicted under different exposure conditions. The 95th percentile for the fraction PCE metabolized at a concentration of 1 ppb was estimated to be 1.89%.

Excretion characteristics of urinary 8-hydroxydeoxyguanosine after dietary exposure to polycyclic aromatic hydrocarbons.

Urinary 8-hydroxydeoxyguanosine (8-OHdG) is considered a noninvasive marker for oxidative stress and also a marker of carcinogenic potential for compounds such as polycyclic aromatic hydrocarbons (PAHs). Although human studies have investigated urinary 8-OHdG concentrations in PAH-exposed workers and the general population, the background level and excretion kinetics of urinary 8-OHdG in humans remain unclear. Two feeding experiments (consumption of barbecued meat of 15 and 30 g/kg for Experiments 1 and 2, respectively) were conducted to examine the excretion characteristics of urinary 8-OHdG. All urine voided over 7 days was collected, but only first morning (approximately 8 A.M.) and last afternoon (approximately 5 P.M.) samples were analyzed for 8-OHdG. Mean background urinary 8-OHdG concentration was 4.76 microg/g creatinine. Statistically significant increases (P < 0.05) in urinary 8-OHdG concentration were observed on the afternoon of the 3rd and 2nd days after barbecued meat consumption for Experiments 1 and 2, respectively. A pattern of diurnal fluctuation (P < 0.05) in 8-OHdG excretion rate was evident, in that the excretion of 8-OHdG was faster during the night than during the day. Additionally, significant (P < 0.05) and strong (r > 0.6) correlations were found between urinary 8-OHdG measured 2-3 days after exposure to barbecued meat, and 1-hydroxypyrene (1-OHP) and 3-hydroxy-benzo[a]pyrene (3-OHBaP) concentrations measured within a half day after such exposure. The current results demonstrate a lag in excretion of urinary 8-OHdG relative to 1-OHP and 3-PHBaP after dietary PAH exposure. These relationships highlight the importance of sampling time when assessing PAH-related DNA lesions through urinary 8-OHdG.

Emission characteristics of plastic syringes sterilized with ethylene oxide--a controlled study.

OBJECTIVES: This study examined the emission characteristics of ethylene oxide (EO)-sterilized syringes under various environmental conditions, aiming to develop control strategies to minimize worker exposure. METHODS: Experiments were performed in a facility in which temperature, relative humidity (RH), and air change rate (ACR) were controlled. RESULTS: Analytical results indicate that the main effects of the four test variables on kinetic parameters were statistically significant (p < 0.05), except for the effect of the product on the decay rate constant, the effect of ACR on maximum EO concentration, and effect of RH on the area under the curve-days 1 and 2. The interactive effects among test variables were also evident, indicating complex emission behaviors. The mean EO emission factors during the days 1 and 2 and at the 48th hour for the 1- and 30-ml products were 2302, 1301, and 1031 mg/m(3)/h, and 871, 490, and 381 mg/m(3)/h, respectively. The times required for air EO concentrations from tested products to return to approximately 0 and 1 ppm (permissible limit) were 417 and 218 h, respectively. CONCLUSIONS: Plastic content, temperature, RH, and ACR affected EO emissions. ACR is an achievable means of control; however, the aeration area/system should be isolated to ensure adequate ventilation is achieved.

Simultaneous determination of airborne carbonyls and aromatic hydrocarbons using mixed sorbent collection and thermal desorption-gas chromatography/mass spectrometric analysis.

Volatile organic chemicals (VOC) such as aromatics and carbonyls are ubiquitous, and have environmental and health significance. This work presents a novel analytical method for simultaneously monitoring airborne carbonyls compounds and aromatic hydrocarbons. Carbonyls were collected onto an adsorbent (Tenax TA, coated with pentafluorophenyl hydrazine (PFPH)) that reacted with carbonyl groups to form thermo-stable derivatives that are suitable for subsequent analysis by thermal-desorption and GC/MS. Aromatic hydrocarbons were collected onto Tenax TA that was packed in the same sampling tube, and analyzed using the same method as carbonyls. Six carbonyls (formaldehyde, acetaldehyde, benzaldehyde, acetone, methyl ethyl ketone and methyl isobutyl ketone) and five aromatics (benzene, toluene, ethylbenzene, xylenes and styrene) were evaluated following standard test protocols. Calibration ranges were 30-200 ng per tube for most test chemicals, and 200-1000 ng per tube for formaldehyde. The analytical precision was 7% or better, and the collection efficiency, tested using a static sampling bag, was between 94 and 98%. PFPH-coated Tenax TA (for collecting carbonyls) needs to be placed in the front section of the tube, and Tenax TA in the back section (for collecting aromatics). The method detection limits of the current method ranged between 0.2 and 25 ng per tube, which corresponded to sub- to 17.2 ppbv (for formaldehyde), based on a typical 6 l sample from a sampling rate of 25 ml/min. Samples were stable for at least ten days under ambient conditions. The proposed method was also tested in the field and proved satisfactory. The proposed method is simple, feasible and has an acceptable accuracy and precision. It can thus be adopted as a reference method for making relevant measurements.

Maternal lactation characteristics after consumption of an alcoholic soup during the postpartum 'doing-the-month' ritual.

OBJECTIVE: The present study examined whether ethanol exposure influences lactation parameters. Specifically, selected constituents in maternal blood and milk and the lactation performance of Chinese lactating mothers were evaluated after they had consumed chicken soup flavoured with sesame oil and rice wine (CSSR), a diet traditionally prescribed during the postpartum 'doing-the-month' ritual. DESIGN: Twenty-three lactating mothers were examined. Informed consent was obtained from each subject. Each subject was tested on two occasions separated by a week. The target alcohol dosage was 0.3 g/kg body weight. Milk and blood samples were collected prior to consumption of soup and at 120 and 150 min, respectively, after consumption. Levels of various constituents were measured. The time for ejection of the first milk droplet and total milk volume yielded were also measured. RESULTS: Consumption of CSSR influenced TAG, insulin and lactate levels in maternal blood. Likewise, consumption of the soup affected milk composition and its nutritional status, particularly total protein, TAG, fatty acid, beta-hydroxybutyrate and lactate levels. CSSR intake significantly affected TAG and lactate levels in milk. The time for the first milk droplet to be ejected was significantly longer in the CSSR group, indicating that the milk-ejecting reflex is inhibited. However, blood prolactin level increased slightly after ethanol intake. Milk yields were reduced after ingestion of CSSR although the difference was not statistically significant. CONCLUSION: Consumption of CSSR affects not only the composition of maternal blood and milk, but also lactation performance. These findings suggest that an alcoholic diet should be avoided during lactation.

Variations in amounts and potential sources of volatile organic chemicals in new cars.

This study examines inter-brand, intra-brand and intra-model variations in volatile organic chemical (VOC) levels inside new cars. The effect of temperature on interior VOC levels was examined using model automobiles with and without the air-conditioning running. Potential sources of VOC were assessed by comparing VOC levels with two interior trims (leather and fabric) and by analyzing VOC emissions from various interior components. Five brands of new car, both domestic and imported, were tested. Twelve targeted VOCs were collected on solid sorbents and analyzed using thermal desorption and GC/FID. VOCs from interior parts and adhesives were identified using solid phase micro-extraction (SPME) coupled with GC/MS. The VOC concentrations varied markedly among brands and within models, and individual VOC levels ranged from below the detection limit (a few mug per cubic meter) to thousands of mug per cubic meter. The intra-model variability (mean, 47%) in the VOC levels was approximately 50% that within each brand (mean, 95%). Although interior trim levels affected VOC levels, the effects differed among brands. Reduction of the cabin temperature reduced most VOC levels, but the impact was not statistically significant. Screening tests for VOCs from interior parts revealed that butylated hydroxytoluene (BHT), a common anti-oxidant, was the most common chemical. Long-chain aliphatic hydrocarbons, particularly C14-C17, were identified in most grease (lubricant) samples, and toluene and xylenes were ubiquitously present in adhesive samples. Process-related compounds, such as plasticizer, were also identified in interior parts. In-cabin VOC levels varied significantly among makes/models and interior trims. Concerned consumers should purchase older new cars from manufacturers since VOC levels inside car cabins normally declines over time. Improved processes or materials with lower VOC emission potential should be used to minimize in-cabin VOC sources for new cars.

Ethylene oxide sterilization in the medical-supply manufacturing industry: assessment and control of worker exposure.

OBJECTIVE: In 2005, the Taiwan Institute of Occupational Safety and Health started an on-site consulting program for the medical supplies manufacturing industry, which use ethylene oxide (EO) as a sterilant, with the goal of enhancing occupational hygiene practices and controlling EO-related risks. This study presents EO exposure assessment results and examines the effectiveness of control measures. METHODS: Detailed surveys, including exposure monitoring, were conducted at 10 factories. Airborne EO was collected using an HBr-coated charcoal tube and analyzed using GC/MS. RESULTS: Sterilizer operators had an average short-term EO exposure level of 27.61 ppm during unloading; mean time-weighted average workshift exposure was 7.35 ppm. High EO concentrations were also present throughout the facilities. Specifically, mean EO concentrations in the aeration area, near the sterilizer and in the warehouse were 10.19, 5.75, and 8.78 ppm, respectively. These findings indicate that immediate controls are needed, and that EO emissions from sterilized products during storage cannot be overlooked. Worker short-term exposures during unloading was inversely correlated (p < 0.05) with the numbers of poststerilization purge cycle applied. The specific controls implemented and their usefulness is discussed. CONCLUSION: Increasing the number of poststerilization purge cycles is a simple approach to eliminating extremely high exposure during unloading. Improvements to ventilation, particularly in the aeration area and warehouse, were also effective in minimizing worker exposures. Use of effective respirator is recommended until the EO exposure levels, averaging 3.41 ppm after the controls, fall below the permissible exposure limit.

Alcohol levels in Chinese lactating mothers after consumption of alcoholic diet during postpartum "doing-the-month" ritual.

This study examined the effects of exposure to ethanol through cultural practices by lactating mothers. Specifically, the pharmacokinetics of alcohol in Chinese lactating mothers was investigated after they consumed chicken soup flavored with sesame oil and rice wine (CSSR), a typically prescribed diet during the postpartum "doing-the-month" period. Experimental findings were employed to estimate the potential ethanol dose to neonates and determine associated health risks. Twenty-three lactating mothers were examined. Informed consent was obtained from each subject. The target alcohol dosage was 0.3g/kg. Milk and blood samples were collected at fixed time intervals from each subject following exposure to CSSR, and alcohol levels were determined. Acute health risks to infants were estimated by comparing the potential infant dosage to an established criterion dose. Blood alcohol level peaked at 20 min after exposure to CSSR and decreased almost linearly thereafter. Alcohol in milk reached a plateau roughly at 20-40 min after exposure to CSSR and then decreased. Alcohol pharmacokinetics among subjects varied widely. The coefficients of variation in subject alcohol concentrations were 16.5-46.2% (mean, 30.0%) for blood and 32.8-57.6% (mean, 44.4%) for milk. Mean maximal alcohol concentration in blood (30.2+/-5.0 mg/dl) was achieved at 23.5+/-7.6 min and in milk (31.6+/-10.3 mg/dl) at 31.7+/-12.7 min. Potential infant doses were 3.0-58.8 mg (mean, 13.4 mg), and the predicted time required for milk alcohol level to return to zero level was 175 min. The acute health risks for infants exposed to alcohol through their mothers' milk under the current exposure scenario are low (hazard index<0.2). Nursing infants at least 3h after ingesting a diet containing alcohol would further reduce potential health risks.

Assessment of occupational health hazards in scrap-tire shredding facilities.

Occupational hygiene conditions in scrap-tire shredding facilities were assessed to identify potential health risk factors for workers and provide a basis for developing future control measures. Specifically, noise, volatile organics and particulate levels were measured at two plants. Particulate/dust levels were measured via filter collection, and were analyzed gravimetrically. Sound pressure levels were measured and their spectral properties analyzed. Moreover, the major chemical species in the samples were identified using GC/MS. Finally, the mutagenic activity associated with the airborne particulates was assessed using a typical Ames test applied to Salmonella strains TA98 and TA100, with or without bio-activation. The noise levels were steady and high throughout the facilities, ranging from 85 to approximately 100 dBA. The octave band spectrum analysis reveals pattern similarity among the different areas. Levels of volatile organics were not significant, but a few mutagens/carcinogens, such as styrene, benzothiazole, phthalate ester and naphthalene were identified. Total particulate levels ranged from 0.43 to 6.54 mg/m(3), while respirable particulates were in the range 0.23-1.25 mg/m(3). Ames testing revealed indirect mutagenicity on strain TA98, indicating possible effects of frame-shift type mutagens. Chemical analysis of airborne particulates confirmed the presence of amines, aniline, quinoline, amides and benzothiazole, which are potentially convertible to frame-shift type mutagenic nitrosoamines. Noise appears to be an occupational hazard for workers at scrap-tire shredding facilities, but the risk associated with the mutagenic/carcinogenic property of particulates requires further confirmation.

The application of diffusive sampling combined with thermal desorption in occupational exposure monitoring--field evaluation.

Diffusive sampling combined with thermal desorption (DSTD) is considered useful in monitoring workers' exposures to organic vapors, not only due to its simplicity of operation in the field but, also, its simplifying the sample treatment, eliminating the use of extracting solvent, and increasing analytical sensitivity. Herein, the feasibility of applying DSTD in field conditions was assessed through a comparison of the results with those from the well-accepted active/charcoal method. Side-by-side active and diffusive (tube-type, Tenax TA as the adsorbent) samples, both personal and area, were collected and analyzed for xylenes, ethyl acetate, styrene, and n-butyl acetate in four different industrial settings. Statistically significant correlations were found between the two methods in personal samples with the correlation coefficients of 0.92, 0.90, 0.83, 0.88, and 0.97 for m&p-xylenes, o-xylene, n-butyl acetate, styrene, and ethyl acetate, respectively. A paired t-test revealed significant difference between the two methods for n-butyl acetate and styrene. For area sampling, statistical differences (p < 0.05) were found between the two methods, except for xylenes. The DSTD method had, mostly, a lower concentration than the active method, with the bias ranging from 10.2 to -54.4 percent. The possible causes for the discrepancies are discussed. These results suggest that though DSTD protocols can be considered as a simple approach for screening workers' exposures to volatile organics, they should be applied with caution since diffusive sampling is potentially affected by various environmental conditions and adsorptive characteristics.