Stefaniak Aleksandr B, Day Gregory A, Harvey Christopher J, Leonard Stephen S, Schwegler-Berry Diane E, Chipera Steve J, Sahakian Nancy M, Chisholm William P
Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
Ind Health. 2007 Dec;45(6):793-803. doi: 10.2486/indhealth.45.793.
Inhalation of cobalt (Co) and tungsten carbide (WC) particles, but not Co or WC alone, may cause hard metal disease, risk of which does not appear to be uniform across cemented tungsten carbide (CTC) production processes. Inhalation of Co alone or in the presence of WC may cause asthma. Hypothesizing that aerosol size, chemical content, heterogeneity, and constituent compaction may be important exposure factors, we characterized aerosols from representative CTC manufacturing processes. Six work areas were sampled to characterize aerosol size distributions (dust, Co) and 12 work areas were sampled to characterize physicochemical properties (using scanning electron microscopy with energy dispersive x-ray spectrometry [SEM-EDX]). Bulk feedstock and process-generated powders were characterized with SEM-EDX and x-ray diffraction. The dust mass median diameter was respirable and the cobalt respirable mass fraction was highest (37%) in grinding. Morphology of particles changed with processing: individual, agglomerate, or aggregates (pre-sintered materials), then mostly compacted particles (subsequent to sintering). Elemental composition of particles became increasingly heterogeneous: mostly discrete Co or W particles (prior to spray drying), then heterogeneous W/Co particles (subsequent work areas). Variability in aerosol respirability and chemical heterogeneity could translate into differences in toxicity and support detailed characterization of physicochemical properties during exposure assessments.
吸入钴（Co）和碳化钨（WC）颗粒，但并非单独吸入Co或WC，可能会导致硬金属病，而且在硬质合金（CTC）生产过程中，其风险似乎并不一致。单独吸入Co或在有WC存在的情况下吸入Co可能会引发哮喘。鉴于气溶胶大小、化学成分、异质性和成分压实可能是重要的暴露因素，我们对来自代表性CTC制造工艺的气溶胶进行了表征。对六个工作区域进行采样以表征气溶胶大小分布（粉尘、Co），并对十二个工作区域进行采样以表征物理化学性质（使用带有能量色散X射线光谱仪的扫描电子显微镜[SEM-EDX]）。使用SEM-EDX和X射线衍射对散装原料和工艺生成的粉末进行了表征。粉尘质量中值直径是可吸入的，并且钴可吸入质量分数在研磨过程中最高（37%）。颗粒形态随加工过程而变化：单个颗粒、团聚体或聚集体（预烧结材料），然后大多是压实颗粒（烧结后）。颗粒的元素组成变得越来越不均匀：大多是离散的Co或W颗粒（喷雾干燥前），然后是不均匀的W/Co颗粒（后续工作区域）。气溶胶可吸入性和化学异质性的变化可能会转化为毒性差异，并有助于在暴露评估期间对物理化学性质进行详细表征。
