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

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.

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.

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).