Unit of Legal Medicine and Forensic Sciences, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy.
Department of Earth Sciences, University of Torino, Turin, Italy.
Front Public Health. 2021 Jul 20;9:678040. doi: 10.3389/fpubh.2021.678040. eCollection 2021.
Biodurability is one of the main determinants of asbestos hazardousness for human health. Very little is known about the actual persistence of asbestos in lungs and its clearance, nor about differences in this regard between the different mineralogical types of asbestos. The aim of the present study was to evaluate the amount, the dimensional characteristics and the mineralogic kinds of asbestos in lungs (measured using SEM-EDS) of a series of 72 deceased subjects who were certainly exposed to asbestos (mainly crocidolite and chrysotile) during their life. Moreover, we investigated possible correlations between the lung burden of asbestos (in general and considering each asbestos type), as well as their dimension (length, width, and l/w ratio) and the duration of exposure, the latency- in case of malignant mesothelioma (MM), the survival and the time since the end of exposure. In 62.5% of subjects, asbestos burden in lungs was lower that the threshold considered demonstrative for occupational exposure. In 29.1% of cases no asbestos was found. Chrysotile was practically not detected. The mean length of asbestos fibers and the length to width ratio were significantly related to the duration of exposure to asbestos. No other statistically significant correlations were found between the amount and dimensional characteristics of asbestos (nor with the relative amount of each asbestos type) and the other chronological variables considered. In conclusion, it was pointed out that chrysotile can be completely removed from human lungs in <8 years and, instead, amphiboles persist much more time. The present results suggest, as well, that the finding of no asbestos in lungs cannot rule out the attribution of MM to asbestos (in particular, chrysotile) inhaled in an occupational setting. This point is of crucial importance from a legal point of view.
生物耐久性是石棉对人类健康危害的主要决定因素之一。关于石棉在肺部的实际持久性及其清除率，以及不同矿物类型的石棉在这方面的差异，人们知之甚少。本研究的目的是评估一系列 72 名已故受试者肺部石棉的数量、尺寸特征和矿物种类（使用 SEM-EDS 测量），这些受试者在其一生中肯定接触过石棉（主要是青石棉和温石棉）。此外，我们还研究了石棉肺负荷（总体上和考虑每种石棉类型）与其尺寸（长度、宽度和长/宽比）之间以及与暴露持续时间、潜伏期（恶性间皮瘤（MM））、生存时间和暴露结束时间之间的可能相关性。在 62.5%的受试者中，肺部石棉负荷低于职业暴露的证明阈值。在 29.1%的病例中未发现石棉。几乎未检测到温石棉。石棉纤维的平均长度和长/宽比与暴露于石棉的持续时间显著相关。在石棉的数量和尺寸特征（以及每种石棉类型的相对数量）与其他考虑的时间变量之间没有发现其他具有统计学意义的相关性。总之，研究结果表明，温石棉可以在<8 年内从人肺部完全清除，而角闪石则会持续更长时间。这些结果还表明，在肺部未发现石棉并不能排除将 MM 归因于在职业环境中吸入的石棉（特别是温石棉）。从法律角度来看，这一点至关重要。
