Kreider Marisa L, Cyrs William D, Tosiano Melissa A, Panko Julie M
Cardno ChemRisk, Pittsburgh, PA 15222, USA;
Cardno ChemRisk, San Francisco, CA 94105, USA;
Ann Occup Hyg. 2015 Nov;59(9):1122-34. doi: 10.1093/annhyg/mev052. Epub 2015 Jul 23.
Current recommendations for nanomaterial-specific exposure assessment require adaptation in order to be applied to complicated manufacturing settings, where a variety of particle types may contribute to the potential exposure. The purpose of this work was to evaluate a method that would allow for exposure assessment of nanostructured materials by chemical composition and size in a mixed dust setting, using carbon black (CB) and amorphous silica (AS) from tire manufacturing as an example. This method combined air sampling with a low pressure cascade impactor with analysis of elemental composition by size to quantitatively assess potential exposures in the workplace. This method was first pilot-tested in one tire manufacturing facility; air samples were collected with a Dekati Low Pressure Impactor (DLPI) during mixing where either CB or AS were used as the primary filler. Air samples were analyzed via scanning transmission electron microscopy (STEM) coupled with energy dispersive spectroscopy (EDS) to identify what fraction of particles were CB, AS, or 'other'. From this pilot study, it was determined that ~95% of all nanoscale particles were identified as CB or AS. Subsequent samples were collected with the Dekati Electrical Low Pressure Impactor (ELPI) at two tire manufacturing facilities and analyzed using the same methodology to quantify exposure to these materials. This analysis confirmed that CB and AS were the predominant nanoscale particle types in the mixing area at both facilities. Air concentrations of CB and AS ranged from ~8900 to 77600 and 400 to 22200 particles cm(-3), respectively. This method offers the potential to provide quantitative estimates of worker exposure to nanoparticles of specific materials in a mixed dust environment. With pending development of occupational exposure limits for nanomaterials, this methodology will allow occupational health and safety practitioners to estimate worker exposures to specific materials, even in scenarios where many particle types are present.
当前针对纳米材料特定暴露评估的建议需要进行调整，以便应用于复杂的制造环境，在这种环境中，多种颗粒类型可能导致潜在暴露。这项工作的目的是评估一种方法，该方法能够在混合粉尘环境中，通过化学成分和尺寸对纳米结构材料的暴露进行评估，以轮胎制造中的炭黑（CB）和无定形二氧化硅（AS）为例。该方法将空气采样与低压分级冲击器相结合，并通过尺寸分析元素组成，以定量评估工作场所的潜在暴露。该方法首先在一家轮胎制造工厂进行了试点测试；在使用CB或AS作为主要填料的混合过程中，用Dekati低压冲击器（DLPI）采集空气样本。通过扫描透射电子显微镜（STEM）结合能量色散光谱（EDS）对空气样本进行分析，以确定颗粒中CB、AS或“其他”成分的比例。从这项试点研究中可以确定，所有纳米级颗粒中约95%被鉴定为CB或AS。随后，在两家轮胎制造工厂用Dekati电动低压冲击器（ELPI）采集样本，并使用相同方法进行分析，以量化对这些材料的暴露。该分析证实，CB和AS是两家工厂混合区域中主要的纳米级颗粒类型。CB和AS的空气浓度分别在约8900至77600和400至22200颗粒/cm³范围内。该方法有可能在混合粉尘环境中对工人接触特定材料的纳米颗粒进行定量估计。随着纳米材料职业接触限值的即将制定，即使在存在多种颗粒类型的情况下，这种方法也将使职业健康与安全从业者能够估计工人对特定材料的暴露情况。
