Development of a fibre size-specific job-exposure matrix for airborne asbestos fibres
Development of a fibre size-specific job-exposure matrix for airborne asbestos fibres
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DOI：
10.1136/oem.2007.033712
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发表时间：
2008-09-01
影响因子：
4.9
通讯作者：
Loomis, D.
中科院分区：
文献类型：
--
作者：
Dement, J. M.;Kuempel, E. D.;Loomis, D.
目的：为了开发一种方法，估计纤维尺寸特定的暴露于空气中的石棉粉尘的流行病学调查中使用的安全-响应relationship.Methods：存档的薄膜过滤器样本收集在查尔斯顿，南卡罗来纳州石棉纺织厂在1964-8年进行了分析，通过透射电子显微镜（TEM），以确定双变量的直径/长度分布的空气中的纤维工厂操作。用于这些分析的协议是基于国际标准化组织（ISO）公布的直接转移法，修改，以提高纤维尺寸的测定，特别是长纤维。程序调整标准的相差显微镜（PCM）纤维浓度的措施，使用TEM数据在工作曝光矩阵（JEM）的开发，以估计纤维尺寸特定的exposs.Results：共84个空气中的灰尘样品被用来测量直径和长度超过18 000纤维或纤维束。与以前的研究一致，一小部分空气中的纤维长度大于5 μ m，但这一比例因工厂操作而异（范围为6.9%至20.8%）。气载纤维的双变量直径/长度分布表示为20个尺寸特定细胞中纤维的比例，这种分布表现出相对较高程度的变异性工厂操作。PCM的调整因素也有很大的不同，在整个plant operation.Conclusions：这些数据提供了新的信息，关于以前研究的纺织设施的空气中的纤维特性。TEM数据表明，工人吸入的绝大多数空气中的纤维长度小于5 mm，因此不包括在基于PCM的纤维计数中。TEM数据被用来开发一种新的纤维尺寸特定的JEM用于更新的队列死亡率研究，以调查纤维尺寸在石棉相关肺部疾病的发展中的作用。
Objective: To develop a method for estimating fibre size-specific exposures to airborne asbestos dust for use in epidemiological investigations of exposure-response relations.Methods: Archived membrane filter samples collected at a Charleston, South Carolina asbestos textile plant during 1964-8 were analysed by transmission electron microscopy (TEM) to determine the bivariate diameter/length distribution of airborne fibres by plant operation. The protocol used for these analyses was based on the direct transfer method published by the International Standards Organization (ISO), modified to enhance fibre size determinations, especially for long fibres. Procedures to adjust standard phase contrast microscopy (PCM) fibre concentration measures using the TEM data in a job-exposure matrix (JEM) were developed in order to estimate fibre size-specific exposures.Results: A total of 84 airborne dust samples were used to measure diameter and length for over 18 000 fibres or fibre bundles. Consistent with previous studies, a small proportion of airborne fibres were longer than >5 mu m in length, but the proportion varied considerably by plant operation (range 6.9% to 20.8%). The bivariate diameter/length distribution of airborne fibres was expressed as the proportion of fibres in 20 size-specific cells and this distribution demonstrated a relatively high degree of variability by plant operation. PCM adjustment factors also varied substantially across plant operations.Conclusions: These data provide new information concerning the airborne fibre characteristics for a previously studied textile facility. The TEM data demonstrate that the vast majority of airborne fibres inhaled by the workers were shorter than 5 mm in length, and thus not included in the PCM-based fibre counts. The TEM data were used to develop a new fibre size-specific JEM for use in an updated cohort mortality study to investigate the role of fibre dimension in the development of asbestos-related lung diseases.