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.