Asbestos in organochlorine insecticide powder sprinkled between pages of antiquarian books in a library in Japan.

Librarians at a university had planned to check the collection prior to the library renovations that began in 2015. They had previous knowledge of the presence of a light greyish-white powder with an unpleasant odour (hereinafter referred to as 'powder') sprinkled between the pages of antiquarian books in the library archive. The purpose of this study was to identify this powder with the help of experts from both inside and outside the university. The powder was qualitatively analysed using gas chromatography with mass spectrometry after hexane extraction. The powder was examined under a polarised light microscope and a field-emission scanning electron microscope equipped with an energy-dispersive X-ray spectrometer. Benzene hexachloride (BHC) was detected in the powder. Talc was the most abundant particle in the powder. The powder also contained 0.52 wt% asbestos, which belonged to the tremolite-actinolite series. No other types of asbestos were detected. The powder was presumed to be a bulking agent for BHC, and its major constituent was talc. This is the first report on asbestos-containing insecticides.

Biological monitoring of occupational exposure to dichloromethane by means of urinalysis for un-metabolized dichloromethane.

The objective of the study is to establish exposure-excretion relationship between dichlorometane (DCM) in air (DCM-A) and in urine (DCM-U) in workplace to confirm a previous report. Male workers in a screen-printing plant participated in the study. Time-weighted average DCM-A was measured by diffusive sampling followed by gas-chromatography (GC), and DCM in end-of-shift urine samples was by head-space GC. The data were subjected to regression and other statistical analyses. In practice, 30 sets of DCM-A and DCM-U values were available. The geometric mean DCM-A was 8.4 ppm and that of DCM-U (as observed) was 41.1 µg/l. The correlation coefficients (0.70-0.85) were statistically significant across the correction for urine density. Thus, the analysis for un-metabolized DCM in end-of-shift urine samples is applicable for biological monitoring of occupational exposure to DCM, in support of and in agreement with the previous report. In conclusion, biological monitoring of occupational DCM exposure is possible by use of analysis for un-metabolized DCM in end-of-shift urine.

Simplified procedures for estimation of biological occupational exposure limits.

OBJECTIVES: To simplify the procedures to estimate biological occupational exposure limits (BOELs) by use of the ratio of geometric mean (GM) concentration of un-metabolized organic solvent in urine (U-GM) over GM organic solvent concentration in air (A-GM) (the [U-GM/A-GM] ratio). METHODS: Occupational Exposure Limits (OELs) and BOELs were cited from publications from the Japan Society of Occupational Health (JSOH) and the American Conference of Governmental Industrial Hygienists (ACGIH). Data on [U-GM/A-GM] and the SLOPE of exposure-excretion regression line were collected from published articles (men and women were treated separately). Correlation analysis and paired t test were employed as the method to examine statistical significances. RESULTS: Significant linear correlation was established between the SLOPE and the [U-GM/A-GM]. Thus, it was considered to be possible to calculate the SLOPE value from the [U-GM/A-GM]. Previously established equation of BOEL = SLOPE × OEL allowed to estimate BOEL values in 22 cases of data sets. The comparison of the estimated BOELs with the existing BOELs (JSOH's BOELs and ACGIH's BEIs) in terms of the ratio of [(estimated BOEL)/(existing BOEL)] showed that the ratios for the 22 cases probably distributed log-normally with a GM of 0.85, and the maximum was 5. Therefore, the estimated BOEL may be generally applicable in occupational health when BOEL remains yet to be established. In the worst case, the estimated BOEL may be five times greater than it should be. The recommended procedures for application of estimated BOEL values were described. CONCLUSION: Simplified procedures for estimation of BOEL values are proposed.

Biological monitoring of occupational ethylbenzene exposure by means of urinalysis for un-metabolized ethylbenzene.

This study aimed to examine quantitative relation between ethylbenzene (EB) in air (EB-A) and un-metabolized EB in urine (EB-U) for biological monitoring of occupational EB exposure by urinalysis for EB. In total, 49 men in furniture production factories participated in the study. Time-weighted average EB-A was monitored by diffusive sampling. Urinalysis for EB was conducted by head-space gas-chromatography with end-of-shift samples. Data were subjected to regression analysis for statistical evaluation. A geometric mean (GM) and the maximum (Max) EB-A levels were 2.1 and 45.5 ppm, respectively. A GM and the Max for EB-U (observed values) were 4.6 and 38.7 µg/l. A significant linear correlation was observed. The regression equation was Y=3.1+0.73X where X is EB-A (ppm) and Y is EB-U (µg/l) (r=0.91, p<0.01). The significant correlation between EB-A and EB-U coupled with a small intercept suggests that biological monitoring of occupational EB exposure is possible by analysis for un-metabolized EB in end-of-shift urine samples. Further validation studies (including those on applicability to women) are envisaged. The feasibility should be examined for biological monitoring and the applicability of the equation among the workers exposed to EB at low levels.

Further examination of log Pow-based procedures to estimate biological occupational exposure limits.

OBJECTIVES: To test the reliability of the procedures (described in a previous article) for estimation of biological occupational exposure limits (BOELs). METHODS: Data on four organic solvents (styrene, ethyl benzene, isopropyl alcohol and tetrachloroethylene) were obtained from recent publications and added to previously cited data for 10 organic solvents. Regression analysis was used for statistical evaluation. RESULTS AND DISCUSSION: The previously reported results obtained using 10 solvents were reproduced by the analysis with 14 solvents. Repeated randomized division of the 14 sets into two subgroups of equal size followed by statistical comparisons did not show a significant difference between two regression lines. This reproducibility suggests that the procedures used to estimate BOELs may be applicable across many solvents, and this may be of particular benefit for protecting the health of workers who work with skin-penetrating solvents.

Evaluation of urinary cyclohexanediols and cyclohexanol as biomarkers of occupational exposure to cyclohexane.

OBJECTIVES: The aim of the present study was to comparatively evaluate the usefulness of urinary cyclohexanediols (CHdiols-U) and cyclohexanol (CHol-U) as biomarkers of occupational exposure to cyclohexane (CH). METHODS: Sixteen subjects (14 men and 2 women) were exposed to CH during proof-printing work. Personal exposure monitoring was conducted during the whole shift on the last working day of the week. The time-weighted average level of exposure to CH (CH-A) was measured using a diffusive sampler. Two urine samples were collected from each worker at different times during the same week: a baseline urine sample (before the first shift of the working week, after a 5-day holiday with no CH exposure) and an end-of-shift urine sample (after the last shift of the same working week, the same day personal exposure monitoring was conducted). CH-A, CHdiols-U and CHol-U were determined using a gas chromatograph-flame ionization detector. RESULTS: The CH-A concentrations ranged from 4.5 to 60.3 ppm, with a geometric mean (GM) of 18.1 ppm. The GMs and ranges (in parenthesis) of the creatinine (cr)-corrected end-of-shift 1,2-CHdiol-U, 1,4-CHdiol-U and CHol-U concentrations were 12.1 (4.1-36.6), 7.5 (2.4-20.1) and 0.4 (0.2-1.0) mg/g cr, respectively. Both CHdiols-U at the end of the shift were significantly correlated with CH-A (correlation coefficients for 1,2-CHdiol-U and 1,4-CHdiol-U of 0.852 and 0.847, respectively). No correlation was observed between CH-A and CHol-U. CONCLUSIONS: CHdiols-U at the end of the last shift of the working week are suitable biomarkers of occupational exposure to CH, but CHol-U is not suitable.

Estimation of biological occupational exposure limit values for selected organic solvents from logartihm of octarol water partition coefficient.

OBJECTIVES: For several organic solvents (solvents in short), biological occupational exposure limits (BOELs) have been established for un-metabolized solvents in urine, based on the solvent exposure-urinary excretion relationship. This study was initiated to investigate the possibiliy of estimating a BOEL from the Pow (the partition coefficient between n-octyl alcohol and water), a physico-chemical parameter. METHODS: Data were available in the literatures for exposure-excretion relationship with regard to 10 solvents for men and 7 solvents for women. RESULTS: Statistical analysis revealed that the slopes (after correction for molecular weights and logarithmic conversion) of the exposure-excretion regression lines linearly correlated (p<0.01) with the log Pow values the respective solvents. No significant difference (p>0.05) was observed between men and women, and it was acceptable to combine the data for the two sexes. Thus the log Pow-log slope relation was represented by a single equation for both sexes. Based on the observations, procedures were established to estimate BOEL values from Pow. Successful estimations of BOELs for styrene, tetrahydrofuran and m-xylene (a representative of xylene isomers) were calculated as examples. CONCLUSIONS: The present study proposed promising procedures for estimation of a BOEL from the Pow.

Promising biological monitoring for occupational 1,2-Dichloropropane exposure by urinalysis for unmetabolized solvent.

OBJECTIVES: The aim of this study was to examine the applicability of urinalysis for unmetabolized solvent to biomonitor 1,2-dichloropropane (1,2-DCP) exposure. METHODS: Thirty three male printers exposed to 1,2-DCP and 5 nonexposed male controls participated in the study. The 8-hr average levels of exposure to 1,2-DCP in air and 1,2-DCP in the end-of-shift urine samples were measured with capillary FID-GC. RESULTS: The geometric mean (the maximum) concentrations was 7.1 ppm (23.1 ppm) for 1,2-DCP in air, and the level in urine (without correction for urine density) was 77 µg/l (247 µg/l). A regression analysis showed a correlation coefficient of 0.909 (p<0.01). No 1,2-DCP was detected in the urine samples from nonexposed subjects. CONCLUSIONS: The high correlation and low background (essentially zero) showed that urinalysis for unmetabolized 1,2-DCP is a promising tool for biomonitoring of occupational exposure to this carcinogenic solvent at lower levels (e.g. <1 ppm).

A method for routine analysis of urinary 4,4'-methylenebis (2-chloroaniline) by gas chromatography-electron capture detection.

OBJECTIVES: The purpose of this study was to develop a simple and cost-effective method for the determination of urinary 4,4'-methylenebis (2-chloroaniline) (MBOCA) by gas chromatography-electron capture detection (GC-ECD) for biological monitoring of occupational exposure to MBOCA. METHODS: MBOCA was prepared by liquid-liquid extraction after alkaline hydrolysis, derivatized with N-methyl-bis (trifluoroacetamide) and then analyzed using GC-ECD. The proposed method was validated in accordance with the US Food and Drug Administration guidance. RESULTS: The calibration curve showed linearity in the range 1-100 µg/l, with a correlation coefficient of >0.999. The limits of detection and quantification were 0.3 µg/l and 1 µg/l, respectively. The recovery was 94-99%. Intraday accuracy, expressed as the deviation from the nominal value, was 90.5-100.3%, and intraday precision, expressed as the relative standard deviation, was 0.3-2.4%. Interday accuracy and precision were 87.8-100.2% and 0.3-4.1%, respectively. CONCLUSIONS: The proposed method is a simple and cost-effective method suitable for routine analyses and could be useful for biological monitoring of occupational exposure to MBOCA.

The relationship between exposure to microbial volatile organic compound and allergy prevalence in single-family homes.

Microbial volatile organic compounds (MVOCs) are a type of VOCs produced by microorganisms. Exposure to 1-octen-3-ol, one of the known MVOCs, has been reported to reduce nasal patency and increase nasal lavage myeloperoxidase, eosinophil cationic proteins, and lysozymes in both experimental and field studies. We reported in a previous paper that 1-octen-3-ol exposure at home is associated with mucosal symptoms. In this study, our aim was to investigate the relationship between asthma and allergies and MVOC exposure in single-family homes. The subjects were 624 inhabitants of 182 detached houses in six regions of Japan. Air samples were collected using diffusive samplers, and the concentrations of eight selected MVOCs were analyzed using gas chromatography/mass spectrometry in selected-ion-monitoring mode. Each inhabitant of each of the dwellings was given a self-administered questionnaire. Among the 609 subjects who answered all of the questions about allergies, history of the medical treatment for asthma, atopic dermatitis, allergic rhinitis, and allergic conjunctivitis within the preceding two years was 4.8%, 9.9%, 18.2%, and 7.1%, respectively. A significant association between 1-octen-3-ol (per log(10) unit) and allergic rhinitis odds ratio (OR): 4.10, 95% confidence interval (CI): 1.71 to 9.80 and conjunctivitis (OR: 3.54, CI: 1.17 to 10.7) was found after adjusting for age, sex, tobacco, wall-to-wall carpeting, signs of dampness, history of treatment for hay fever, and other potentially relevant environmental factors. No relationships were found between any MVOCs and asthma or atopic dermatitis after the adjustment. The levels of MVOCs and airborne fungi were only weakly correlated. These results are consistent with previous studies that have associated higher levels of 1-octen-3-ol exposure with increased irritation of nasal and ocular mucosae. Although the indoor-air concentrations of 1-octen-3-ol found in this study were relatively low, we conclude that exposure to MVOC may be related to rhinitis and conjunctivitis.

Exposure assessment of ETBE in gas station workers and gasoline tanker truck drivers.

OBJECTIVES: In order to measure occupational exposure concentrations of ethyl tertiary-butyl ether (ETBE), we developed a diffusive sampling method for monitoring ETBE and performed an ETBE exposure assessment. METHODS: The applicability of diffusive samplers was examined by exposing the samplers to ETBE vapor in test chambers. The personal exposure levels of workers and airborne concentrations were measured at 4 gas stations. RESULTS: The ETBE sampling rate for the diffusive samplers (VOC-SD, Sigma-Aldrich Japan) was 25.04 ml/min (25°C). Compared with the active sampling method, the diffusive samplers could be used for short-term measurements and in environments containing a mixture of organic solvents. The geometric mean (GM) of TWA-8h ETBE was 0.08 ppm (0.02-0.28 ppm) in 28 gas station workers and 0.04 ppm (0.01-0.21 ppm) in 2 gasoline tanker truck drivers. With regard to ETBE airborne concentrations, the GM was 4.12 ppm (0.93-8.71 ppm) at the handles of hanging pumps but dropped to less than 0.01 ppm (less than 0.01-0.01 ppm) at the side of a public road. CONCLUSION: The diffusive sampling method can be used for the measurement of occupational ETBE exposure. The threshold limit of TLV-TWA 5 ppm recommended by the ACGIH was not exceeded in any of the workers in this study.

Use of a holder-vacuum tube device to save on-site hands in preparing urine samples for head-space gas-chromatography, and its application to determine the time allowance for sample sealing.

To facilitate urine sample preparation prior to head-space gas-chromatographic (HS-GC) analysis. Urine samples containing one of the five solvents (acetone, methanol, methyl ethyl ketone, methyl isobutyl ketone and toluene) at the levels of biological exposure limits were aspirated into a vacuum tube via holder, a device commercially available for venous blood collection (the vacuum tube method). The urine sample, 5 ml, was quantitatively transferred to a 20-ml head-space vial prior to HS-GC analysis. The loaded tubes were stored at +4 ℃ in dark for up to 3 d. The vacuum tube method facilitated on-site procedures of urine sample preparation for HS-GC with no significant loss of solvents in the sample and no need of skilled hands, whereas on-site sample preparation time was significantly reduced. Furthermore, no loss of solvents was detected during the 3-d storage, irrespective of hydrophilic (acetone) or lipophilic solvent (toluene). In a pilot application, high performance of the vacuum tube method in sealing a sample in an air-tight space succeeded to confirm that no solvent will be lost when sealing is completed within 5 min after urine voiding, and that the allowance time is as long as 30 min in case of toluene in urine. The use of the holder-vacuum tube device not only saves hands for transfer of the sample to air-tight space, but facilitates sample storage prior to HS-GC analysis.

Relationship between selected indoor volatile organic compounds, so-called microbial VOC, and the prevalence of mucous membrane symptoms in single family homes.

Microorganisms are known to produce a range of volatile organic compounds, so-called microbial VOC (MVOC). Chamber studies where humans were exposed to MVOC addressed the acute effects of objective and/or subjective signs of mucosal irritation. However, the effect of MVOC on inhabitants due to household exposure is still unclear. The purpose of this epidemiological study was to measure indoor MVOC levels in single family homes and to evaluate the relationship between exposure to them and sick building syndrome (SBS). All inhabitants of the dwellings were given a self-administered questionnaire with standardized questions to assess their symptoms. Air samples were collected and the concentrations of eight selected compounds in indoor air were analyzed by gas chromatography/mass spectrometry - selective ion monitoring mode (GC/MS-SIM). The most frequently detected MVOC was 1-pentanol at a detection rate of 78.6% and geometric mean of 0.60 microg/m(3). Among 620 participants, 120 (19.4%) reported one or more mucous symptoms; irritation of the eyes, nose, airway, or coughing every week (weekly symptoms), and 30 (4.8%) reported that the symptoms were home-related (home-related symptoms). Weekly symptoms were not associated with any of MVOC, whereas significant associations between home-related mucous symptoms and 1-octen-3-ol (per log(10)-unit: odds ratio (OR) 5.6, 95% confidence interval (CI): 2.1 to 14.8) and 2-pentanol (per log(10)-unit: OR 2.3, 95% CI: 1.0 to 4.9) were obtained after adjustment for gender, age, and smoking. Associations between home-related symptoms and 1-octen-3-ol remained after mutual adjustment. However, concentrations of the selected compounds in indoors were lower than the estimated safety level in animal studies. Thus, the statistically significant association between 1-octen-3-ol may be due to a direct effect of the compounds or the associations may be being associated with other offending compounds. Additional studies are needed to evaluate these possibilities.

Blood lead level and cardiovascular risk factors among bus drivers in Bangkok, Thailand.

This study aimed to clarify the role of blood lead level (Pb-B) as one of the cardiovascular risk factors. To evaluate the cardiovascular risk the second derivative finger photoplethysmogram (SDPTG) was used. The subjects comprised of 420 male bus drivers in Thailand. The subjects' age ranged from 20 to 60 yr. Mean age (+/- standard deviation) were 41.6 (+/- 7.7) yr. Mean working years was 8.8 (+/- 6.8) yr. Pb-B ranged from 2.5 to 16.2 microg/dl with the mean Pb-B of 6.3 (+/- 2.2) microg/dl. The mean of aging index of SDPTG (SDPTG-AI) were -0.50 (+/- 0.30). The SDPTG-AI increases with age, Pb-B, smoking and alcohol consumption. There was significant correlation between Pb-B and SDPTG-AI after controlling for age, body mass index and lifestyle factors. These results suggest that Pb-B is possibly an independent cardiovascular risk factor for bus drivers exposed to lower level of lead.

Limited validity of o-cresol and benzylmercapturic acid in urine as biomarkers of occupational exposure to toluene at low levels.

This study was initiated to evaluate o-cresol and benzylmercapturic acid in urine in comparison with other biomarkers, as tools to estimate the intensity of occupational exposure to toluene at low levels. In total, 108 solvent exposed workers (engaged in tape production) and 17 non-exposed controls (all men) participated in the study. The surveys were conducted in the second half of working weeks. Diffusive sampling was conducted to measure 8-h time-weighted average intensity of occupational exposure to toluene. Blood and urine samples were collected at the end of a working shift. Blood samples were subjected to analysis for toluene (Tol-B), and urine samples were analyzed for benzyl alcohol (BeOH-U), benzylmercapturic acid (BMA-U), o-cresol (o-CR-U), hippuric acid (HA-U) and toluene (Tol-U) by the methods previously described. The toluene concentrations in workplaces were low in general, with a geometric mean (GM) and the maximum concentration of 1.9 ppm and 8.8 ppm, respectively. The statistical analyses of the six biomarkers for correlation with air-borne toluene showed that both Tol-B and Tol-U gave a high correlation coefficient of 0.58 to 0.61 (p<0.01), whereas the coefficients for BeOH-U and BMA-U together with HA-U were all low (up to 0.22, depending on the correction for urine density) and statistically insignificant (p>0.10) in most cases. o-CR-U had an intermediary coefficient of 0.20 (p<0.05). Comparison with previous publications disclosed that BeOH-U, BMA-U and HA-U correlate with toluene in air when the exposure is intense (e.g., 50 ppm or above), but no longer proportional to air-borne toluene when the exposure is low, e.g., 2 ppm. Such appeared to be also the case for o-CR-U. In over-all evaluation, the validity of o-CR-U in monitoring occupational exposure to toluene at low levels (e.g., 2 ppm) appear to be limited, and BMA-U is not an appropriate biomarker. BeOH-U and HA-U are also inappropriate for this purpose. Only Tol-B and Tol-U may be employed to estimate toluene exposure at low levels.

Changes in correlation coefficients of exposure markers as a function of intensity of occupational exposure to toluene.

This study was initiated to identify a marker of choice to monitor occupational exposure to toluene through quantitative evaluation of changes in correlation coefficients (CCs), taking advantage of a large database. Six known or proposed exposure markers in end-of-shift blood (B) and urine (U) were studied, i.e., toluene in blood (Tol-B) and benzyl alcohol, benzylmercapturic acid, o-cresol, hippuric acid and toluene in urine (BeOH-U, BMA-U, o-CR-U, HA-U, and Tol-U, respectively). To construct a database, data on 8-h time-weighted average intensity of occupational exposure to toluene and resulting levels of the six exposure markers in blood or urine were cited for 901 cases from previous four publications of this study group and combined with 146 new cases. In practice, 874 cases (all men) were available when extremely dilute or dense urine samples were excluded. The 874 cases were classified taking the upper limit (from 120 ppm to 1 ppm) of the toluene exposure concentration, and the CCs for the six markers with TWA toluene exposure intensity were calculated. For further evaluation, the 874 cases were divided into 10 per thousand in terms of TWA toluene exposures, and several 10 per thousand were combined so that sufficient numbers of cases were available for calculation of the CCs at various levels of toluene exposure. Perusal was made to know whether or not and which one of the six makers gave significant CC even at low level of toluene exposure. The CCs for BMA-U, o-CR-U and HA-U with TWA toluene exposure were well >0.7 when toluene exposure was intense (e.g., up to 60-100 ppm as the upper limit of the exposure range), but were reduced when the upper limit of toluene exposure was less than 50 ppm, and the CCs were as small as <==0.2 when the upper limit was about 10 ppm or less. In contrast, Tol-U and Tol-B were correlated with exposure to toluene down to the 0.4 when the cases in the 60th-100th per thousand were examined. The CCs for Tol-U and Tol-B were >0.3 also for cases in the 0th-60th or 30th-70th per thousand, whereas the CCs for other four markers were <0.3. In over-all evaluation, it was concluded that HA and o-CR are among the markers of choice to monitor occupational toluene exposure at high levels, and that only un-metabolized toluene in urine or in blood is recommended when toluene exposure level is low (e.g., 10 ppm or less). Toluene in urine may be preferred rather than that in blood due to practical reasons, such as non-invasiveness.

Stability in urine of authentic phenylglyoxylic and mandelic acids as urinary markers of occupational exposure to styrene.

Phenylglyoxylic acid (PhGA) and mandelic acid (MA) are two popular urinary markers of occupational exposure to styrene, but PhGA has been considered to be relatively unstable when urine samples are stored. This study was initiated to examine the stability of PhGA in urine under two storage conditions, i.e., at room temperature (at 25 degrees C) and in refrigeration (at 4 degrees C) for up to 14 days. The experiments showed that no substantial decrease was observed in either PhGA or MA even at room temperature within one day, but, depending on urine samples, a gradual decrease in PhGA took place both at 4 degrees C and more markedly at 25 degrees C when kept for a week. Further reduction was observed in two weeks even at 4 degrees C. No reduction was observed in MA up to two weeks both at 4 degrees C and at 25 degrees C. The observation on stability of MA and limited stability of PhGA (i.e., no significant decrease for 4 days when stored as refrigerated) was confirmed by a repeated experiment. Further analyses disclosed that PhGA when stored at 4 degrees C tended to be more unstable when urine samples were alkaline (e.g., at pH 8) rather than acidic (e.g., at pH 6 or below), but the trend varied subject to individual samples. Thus, the practical recommendation is that urine samples should be analyzed on the day of collection if all possible, or kept at 4 degrees C, or more preferably at -20 degrees C. Refrigeration will allow storage of up to 4 days without substantial decrease in either PhGA or MA.