Evaluation of biomarkers of occupational exposure to toluene at low levels

Kawai, Takeshi; Ukai, Hirohiko; Ito, Osamu; Maejima, Yuki; Fukui, Yoshinari; Ohashi, Fumiko; Okamoto, Susumu; Takada, Shiro; Ikeda, Masayuki

doi:10.1007/s00420-007-0203-2

Cited by 31 publications

(29 citation statements)

References 34 publications

(39 reference statements)

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“…The correlation of o-CR-U ob was less significant with r=0.20 and p<0.05, whereas BeOH-U ob and BMA-U ob did not correlate significantly (r=0.16 and 0.11, respectively, with p>0.10 for both; Table 3). In the two previous studies, one 10) with toluene exposure at moderate levels (at 10 ppm as GM and at 121 ppm as the maximum) and the other 11) at low levels (at 1.6 ppm as GM and 26.5 ppm as the maximum), Tol-U correlated with TWA toluene concentrations in air not only at moderate levels but at low levels. No Tol-B was examined in the moderate exposure study 10) , but separate studies showed that Tol-B significantly correlates with air-borne toluene at low levels 11) as well as at high levels (the maximum level being 132 ppm) 23 Abbreviations are: BeOH-U, benzyl alcohol in urine; BMA-U, benzylmercapturic acid in urine; o-CR, o-cresol in urine; HA-U, hippuric acid in urine; Tol-U, toluene in urine and Tol-B, toluene in blood.…”

Section: Discussionmentioning

confidence: 76%

“…The survey was conducted on the second half of working weeks following the design as previously described 10,11) . In short, TWA toluene exposure concentration was monitored by use of diffusive samplers 12) which were placed on the working cloth (at the chest pocket level) of each worker for approximately 8 h (i.e., typically from 09:00 to 17:00).…”

Section: Air-borne Toluene Monitoring and Biological Monitoring By Mmentioning

confidence: 99%

“…It was also observed that un-metabolized toluene both in blood and urine is a better marker of the exposure to toluene not only at moderate levels (e.g., at 50 ppm) but at lower levels (e.g., 2 ppm) 11) .…”

Section: Introductionmentioning

confidence: 98%

“…Comparative evaluation of recently developed biomarkers to detect occupational toluene exposure was conducted in previous two analyses to show that, whereas the traditional biomarker of hippuric acid is valid when the time-weighted average (TWA) toluene exposure is rather intense 10) , this marker only poorly correlates with the exposure when toluene exposure is low, e.g., at less than 10 ppm 10,11) . It was also observed that un-metabolized toluene both in blood and urine is a better marker of the exposure to toluene not only at moderate levels (e.g., at 50 ppm) but at lower levels (e.g., 2 ppm) 11) .…”

Section: Introductionmentioning

confidence: 99%

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Limited Validity of o-Cresol and Benzylmercapturic Acid in Urine as Biomarkers of Occupational Exposure to Toluene at Low Levels

et al. 2008

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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), ocresol (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.

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Section: Discussionmentioning

confidence: 76%

Section: Air-borne Toluene Monitoring and Biological Monitoring By Mmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Limited Validity of o-Cresol and Benzylmercapturic Acid in Urine as Biomarkers of Occupational Exposure to Toluene at Low Levels

et al. 2008

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“…The use was not limited to occupational health where the method was originally developed [1][2][3][4][5][6] , but also in environmental health fields 7,8) . The method has been applied to analysis for un-metabolized mother chemicals 1,[9][10][11][12] as well as for metabolites after proper automated derivatization of metabolites to increase volatility [13][14][15][16] .…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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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°C 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.

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Addendum zu Toluol [BAT Value Documentation in German language, 2018]

Hartwig¹,

Arand²

2018

The MAK‐Collection for Occupational Health and Safety

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In 2017, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has derived a BAT value (“Biologischer Arbeitsstoff‐Toleranzwert”) for toluene [CAS NO. 108‐88‐3 ] in urine to characterize the internal exposure at the workplace. Available publications are described in detail. The evaluation of the BAT value was based on the relationship between toluene uptake by inhalation at the MAK value and the corresponding urinary excretion rate of unmetabolized toluene. An eight‐hour exposure to the present MAK value of 190 mg toluene/m 3 correlated with a mean urinary toluene concentration of approximately 75 µg/l. Therefore, a BAT value of 75 µg toluene/l urine was evaluated. Sampling time is at the end of exposure or the end of the working shift.

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Evaluation of biomarkers of occupational exposure to toluene at low levels

Abstract: Taking the non-invasive nature of sampling together, Tol in the end-of-shift spot urine sample appears to be the marker of choice for biological monitoring of occupational exposure to Tol at low levels such as <2 ppm as a geometric mean.

Cited by 31 publications

References 34 publications

Limited Validity of o-Cresol and Benzylmercapturic Acid in Urine as Biomarkers of Occupational Exposure to Toluene at Low Levels

Limited Validity of o-Cresol and Benzylmercapturic Acid in Urine as Biomarkers of Occupational Exposure to Toluene at Low Levels

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

Addendum zu Toluol [BAT Value Documentation in German language, 2018]

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