Carbon Nanotube and Nanofiber Exposure Assessments: An Analysis of 14 Site Visits
Carbon Nanotube and Nanofiber Exposure Assessments: An Analysis of 14 Site Visits
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DOI：
10.1093/annhyg/mev020
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发表时间：
2015-07-01
影响因子：
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通讯作者：
Deddens, James A.
中科院分区：
文献类型：
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作者：
Dahm, Matthew M.;Schubauer-Berigan, Mary K.;Deddens, James A.
最近的证据表明，接触碳纳米管（CNT）和碳纳米纤维（CNF）可能会对健康产生广泛的影响。作为回应，国家职业安全与健康研究所（NIOSH）为CNT和CNF设定了推荐的暴露限值（REL）：1 μ g/m（-3）作为可吸入颗粒级元素碳（EC）的8小时时间加权平均值（TWA）。本研究的目的是在美国CNT和CNF制造商和用户中进行全行业暴露评估。共访问了14个地点，以评估CNT（13个地点）和CNF（1个地点）的暴露情况。采用NIOSH方法5040，采集个人呼吸带（PBZ）和区域样本，测定EC的可吸入和可吸入质量浓度。在9个地点收集了可吸入PBZ样本，而在其余5个地点同时收集了可吸入和可吸入PBZ样本。透射电子显微镜（TEM）PBZ和面积样品也收集在可吸入的大小部分和分析，以量化和大小CNT和CNF团聚体和纤维暴露。可吸入EC PBZ浓度范围为0.02至2.94 μ g/m3，几何平均值（GM）为0.34 μ g/m3，8小时TWA为0.16 μ g/m3。多溴联苯醚样本中的可吸入粒级EC范围为0.01至79.57 μ g m（-3），GM为1.21 μ g m（-3）。通过TEM分析的PBZ样品显示浓度范围为0.0001至1.613 CNT或CNF-结构/cm（3），GM为0.008，8小时TWA浓度为0.003。发现最常见的CNT结构尺寸是2-5 μ m范围内的较大附聚物以及>5 μ m的附聚物。在可吸入样品中观察到EC质量与TEM结构计数之间的统计学显著相关性（斯皮尔曼rho = 0.39，P < 0.0001）。总的来说，EC PBZ和区域TWA样品低于NIOSH REL（96%的可吸入粒径小于1 μ g m（-3）），而30%的可吸入PBZ EC样品大于1 μ g m（-3）。直到更多的信息是已知的健康影响与较大的团聚体，它似乎是谨慎的评估工人暴露于空气中的CNT和CNF材料通过监测EC在两个可吸入和可吸入的尺寸分数。应同时采集TEM样品，以确认CNT和CNF的存在。
Recent evidence has suggested the potential for wide-ranging health effects that could result from exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF). In response, the National Institute for Occupational Safety and Health (NIOSH) set a recommended exposure limit (REL) for CNT and CNF: 1 mu g m(-3) as an 8-h time weighted average (TWA) of elemental carbon (EC) for the respirable size fraction. The purpose of this study was to conduct an industrywide exposure assessment among US CNT and CNF manufacturers and users. Fourteen total sites were visited to assess exposures to CNT (13 sites) and CNF (1 site). Personal breathing zone (PBZ) and area samples were collected for both the inhalable and respirable mass concentration of EC, using NIOSH Method 5040. Inhalable PBZ samples were collected at nine sites while at the remaining five sites both respirable and inhalable PBZ samples were collected side-by-side. Transmission electron microscopy (TEM) PBZ and area samples were also collected at the inhalable size fraction and analyzed to quantify and size CNT and CNF agglomerate and fibrous exposures. Respirable EC PBZ concentrations ranged from 0.02 to 2.94 mu g m(-3) with a geometric mean (GM) of 0.34 mu g m(-3) and an 8-h TWA of 0.16 mu g m(-3). PBZ samples at the inhalable size fraction for EC ranged from 0.01 to 79.57 mu g m(-3) with a GM of 1.21 mu g m(-3). PBZ samples analyzed by TEM showed concentrations ranging from 0.0001 to 1.613 CNT or CNF-structures per cm(3) with a GM of 0.008 and an 8-h TWA concentration of 0.003. The most common CNT structure sizes were found to be larger agglomerates in the 2-5 mu m range as well as agglomerates >5 mu m. A statistically significant correlation was observed between the inhalable samples for the mass of EC and structure counts by TEM (Spearman rho = 0.39, P < 0.0001). Overall, EC PBZ and area TWA samples were below the NIOSH REL (96% were < 1 mu g m(-3) at the respirable size fraction), while 30% of the inhalable PBZ EC samples were found to be > 1 mu g m(-3). Until more information is known about health effects associated with larger agglomerates, it seems prudent to assess worker exposure to airborne CNT and CNF materials by monitoring EC at both the respirable and inhalable size fractions. Concurrent TEM samples should be collected to confirm the presence of CNT and CNF.