Batterman S A, Franzblau A, D'Arcy J B, Sargent N E, Gross K B, Schreck R M
Environmental and Industrial Health, The University of Michigan, Ann Arbor 48109-2029, USA.
Int Arch Occup Environ Health. 1998 Jul;71(5):325-35. doi: 10.1007/s004200050288.
Due to their transient nature, short-term exposures can be difficult to detect and quantify using conventional monitoring techniques. Biological monitoring may be capable of registering such exposures and may also be used to estimate important toxicological parameters. This paper investigates relationships between methanol concentrations in the blood, urine, and breath of volunteers exposed to methanol vapor at 800 ppm for periods of 0.5, 1, 2, and 8 h. The results indicate factors that must be considered for interpretation of the results of biological monitoring. For methanol, concentrations are not proportional to the exposure duration due to metabolic and other elimination processes that occur concurrently with the exposure. First-order clearance models can be used with blood, breath, or urine concentrations to estimate exposures if the time that has elapsed since the exposure and the model parameters are known. The 0.5 to 2-h periods of exposure were used to estimate the half-life of methanol. Blood data gave a half-life of 1.44+/-0.33 h. Comparable but slightly more variable results were obtained using urine data corrected for voiding time (1.55+/-0.67h) and breath data corrected for mucous membrane desorption (1.40+/-0.38 h). Methanol concentrations in blood lagged some 15-30 min behind the termination of exposure, and concentrations in urine were further delayed. Although breath sampling may be convenient, breath concentrations reflect end-expired or alveolar air only if subjects are in a methanol-free environment for 30 min or more after the exposure. At earlier times, breath concentrations included contributions from airway desorption or diffusion processes. As based on multicompartmental models, the desorption processes have half-lives ranging between 0.6 and 5 min. Preliminary estimates of the mucous membrane reservoir indicate contributions of under 10% for a 0.5-h exposure and smaller effects for longer periods of exposure.
由于其短暂性，使用传统监测技术很难检测和量化短期暴露。生物监测可能能够记录此类暴露，还可用于估计重要的毒理学参数。本文研究了暴露于800 ppm甲醇蒸汽0.5、1、2和8小时的志愿者血液、尿液和呼出气体中甲醇浓度之间的关系。结果表明了生物监测结果解释中必须考虑的因素。对于甲醇，由于与暴露同时发生的代谢和其他消除过程，浓度与暴露持续时间不成正比。如果已知暴露后经过的时间和模型参数，一阶清除模型可用于根据血液、呼出气体或尿液浓度估计暴露情况。利用0.5至2小时的暴露时间来估计甲醇的半衰期。血液数据得出的半衰期为1.44±0.33小时。使用经排尿时间校正的尿液数据（1.55±0.67小时）和经粘膜解吸校正的呼出气体数据（1.40±0.38小时）得到了可比但稍具变异性的结果。血液中的甲醇浓度在暴露终止后约15 - 30分钟出现滞后现象，尿液中的浓度延迟更久。尽管呼气采样可能很方便，但只有在暴露后受试者处于无甲醇环境30分钟或更长时间时，呼出气体浓度才反映终末呼出或肺泡气中的浓度。在更早的时间，呼出气体浓度包括气道解吸或扩散过程的贡献。基于多室模型，解吸过程的半衰期在0.6至5分钟之间。粘膜储库的初步估计表明，0.5小时暴露的贡献低于10%，暴露时间更长时影响更小。
