Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, Tainan, Taiwan.
J Hazard Mater. 2010 Apr 15;176(1-3):389-94. doi: 10.1016/j.jhazmat.2009.11.042. Epub 2009 Nov 13.
In this study, field samplings were conducted in three workplaces of a foundry plant, including the molding, demolding, and bead blasting, respectively. Three respirable aerosol samplers (including a 25-mm aluminum cyclone, nylon cyclone, and IOSH cyclone) were used side-by-side to collect samples from each selected workplace. For each collected sample, the uniformity of the deposition of respirable dusts on the filter was measured and its free silica content was determined by both the DOF XRD method and NIOSH 7500 XRD method (i.e., the reference method). A same trend in measured uniformities can be found in all selected workplaces: 25-mm aluminum cyclone>nylon cyclone>IOSH cyclone. Even for samples collected by the sampler with the highest uniformity (i.e., 25-mm aluminum cyclone), the use of the DOF XRD method would lead to the measured free silica concentrations 1.15-2.89 times in magnitude higher than that of the reference method. A new filter holder should be developed with the minimum uniformity comparable to that of NIOSH 7500 XRD method (=0.78) in the future. The use of conversion factors for correcting quartz concentrations obtained from the DOF XRD method based on the measured uniformities could be suitable for the foundry industry at this stage.
在这项研究中，在铸造厂的三个工作场所进行了现场采样，分别是造型、脱模和喷砂。三个可吸入气溶胶采样器（包括一个 25 毫米的铝合金旋风分离器、尼龙旋风分离器和 IOSH 旋风分离器）并排使用，从每个选定的工作场所收集样品。对于每个收集的样品，测量了可吸入粉尘在过滤器上沉积的均匀性，并通过 DOF XRD 法和 NIOSH 7500 XRD 法（即参考方法）测定其游离二氧化硅含量。在所有选定的工作场所都可以发现测量均匀度的相同趋势：25 毫米铝合金旋风分离器>尼龙旋风分离器>IOSH 旋风分离器。即使是使用均匀度最高的采样器（即 25 毫米铝合金旋风分离器）收集的样品，使用 DOF XRD 法也会导致测量的游离二氧化硅浓度比参考方法高 1.15-2.89 倍。未来应开发一种新的过滤器支架，其均匀度至少应与 NIOSH 7500 XRD 法（=0.78）相当。基于测量的均匀度，使用转换因子来校正 DOF XRD 法获得的石英浓度，在现阶段可能适用于铸造行业。
