Gases and organic solvents in urine as biomarkers of occupational exposure: a review

Abstract

A brief review of urine analysis in studies of occupational exposure to volatile organic compounds and gases is provided. Analysis of exhaled breath for volatile compounds does not have a long history in occupational medicine. A number of studies has been undertaken since the 1980s, and the methods are well enough accepted to be put forward as biological equivalents of threshold limit values (TLVs) for some volatile organic compounds (VOCs) such as acetone; methanol; methyl ethyl ketone (MEK); methyl isobutyl ketone (MIBK); tetrahydrofurane; dichloromethane. In the last 20 years many scientific articles have shown that the urinary concentrations of unchanged solvents are correlated with environmental exposure and could be used for biological monitoring. The use of urine analysis of unchanged solvents in occupational applications is not yet widespread. Nonetheless, in the short time since its application, a number of important discoveries has been made, and the future appears bright for this branch of analysis. In this paper, the basic concepts and methodology of urine analysis are briefly presented with a critical revision of the literature on this matter. The excretion mechanisms of organic solvents in urine are discussed, with regard to biological variability, and the future directions of research are described.

Unmetabolized VOCs in urine as biomarkers of low level occupational exposure

“…The data on the relationship between VOC concentrations in the air and concentrations of unchanged compounds in blood and for toluene, ethylbenzene, xylene and mesitylene varied from 0.45 h to 0.88 h for phase I and from 6.7 h to 19.2 h for phase II [2]. The data reported recently for exposure in occupational setting show that the determination of unmetabolized solvents in urine provides a highly sensitive and specific index of exposure to VOCs [3][4][5][6][7][8][9][10][11]. The purpose of the present study was to compare the validity of various biomarkers of exposure to toluene, ethylbenzene and xylene at low levels of occupational exposure and to find out whether the determination of unchanged VOCs in urine would be useful for the assessment of exposure around and below the current occupational exposure limit.…”

Determination of benzene, toluene and N-hexane in urine and blood by headspace solid-phase microextration/gas-chromatography for the biomonitoring of occupational exposure

“…Benzene was not detected in any sample, regardless the use or not of cigarette by the worker. Although the levels of the solvent in biological fluids of smokers are higher than in the non smokers, concentrations varying between 191-942 ng L -1 in urine 39 and 81-1136 ng L -1 in blood. 40 The LOQ of the method used is higher than its detection in situations of environmental or smoking exposure.…”

“…n-Hexane was detected in blood from only two volunteers (33.0 and 41.3 µg L -1 ). Imbriani and coworkers 39,41,42 reported that the urine concentration of unaltered n-hexane corresponding to the TLV-TWA (50 ppm, ACGIH) was 13.09 µg L -1 , not mentioning the corresponding value for blood samples. Although no positive results were obtained for n-hexane in the urine samples from exposed workers, the LOQ established for both fibers permits its use for analysis at concentrations lower than the reported biological limit.…”

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

“…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] .…”