Hesterberg T W, Hart G A
Mountain Technical Center, A Division of Schuller International, Littleton, Colorado 80127, USA.
Regul Toxicol Pharmacol. 1994 Dec;20(3 Pt 2):S35-46.
In a recent rat inhalation study, 2 years of exposure to high concentrations of fiberglass (FG) resulted in no treatment-related fibrosis or thoracic tumors. To determine the relevancy of this study for human risk assessment, it is important to compare the rat experimental exposure levels with those of humans. Data on human exposures were taken from several studies and included FG manufacturing, installation and removal, and ambient air. FG levels in the rat aerosol were 200,000-fold higher than indoor air, > 2000-fold higher than during FG insulation manufacturing, and > 1000-fold higher than FG batt installation. The rat aerosol was 30-fold more concentrated than the highest human exposure (blowing installation of unbound FG). Rat FG lung burden also vastly exceeded that of FG workers, which was not significantly elevated above nonworker levels. The amount of fibers/mg dry lung for the rat after lifetime exposure was > 4000-fold greater than for the FG worker, average exposure 11 years. Aerosol and lung fiber dimensions in the rat study were comparable to those of human exposures. From these comparisons, it can be concluded that the exposure level in the rat inhalation study was sufficiently, if not excessively, high in comparison to human exposures. Increasing the experimental exposure in the rat studies would not serve to mirror human environmental or occupational exposures.
在最近一项大鼠吸入研究中，2年暴露于高浓度玻璃纤维（FG）并未导致与治疗相关的纤维化或胸部肿瘤。为确定该研究对人类风险评估的相关性，将大鼠实验暴露水平与人类暴露水平进行比较很重要。人类暴露数据取自多项研究，包括FG制造、安装和移除以及环境空气。大鼠气雾剂中的FG水平比室内空气高200,000倍，比FG绝缘材料制造期间高2000倍以上，比FG毡安装期间高1000倍以上。大鼠气雾剂的浓度比人类最高暴露水平（未结合FG的吹气安装）高30倍。大鼠肺部FG负荷也大大超过FG工人，FG工人的肺部FG负荷并未显著高于非工人水平。终生暴露后大鼠每毫克干肺中的纤维数量比FG工人（平均暴露11年）高4000倍以上。大鼠研究中的气雾剂和肺部纤维尺寸与人类暴露的尺寸相当。从这些比较中可以得出结论，与人类暴露相比，大鼠吸入研究中的暴露水平即使不过高也足够高。增加大鼠研究中的实验暴露水平无助于反映人类环境或职业暴露情况。
