澆鑄作業逸散氣膠放射特性及細胞毒性之研究

過往文獻指出，金屬鑄造廠澆鑄過程中容易產生金屬薰煙及逸散微粒懸浮，但其微粒中之放射特性卻較少被研究，且其逸散微粒特性，如粒徑大小、劑量濃度、放射活度及重金屬成分對於人體影響之貢獻度仍不明確。因此本研究對鑄造廠逸散微粒進行採樣及分析後，以人體肺纖維母細胞（WI-38細胞）進行微粒之細胞毒性暴露，並試圖以統計分析方式釐清各項因子之貢獻度。本研究於台灣中部地區之鑄銅及鑄鋁澆鑄作業現場，以微孔均勻沉積衝擊器（Micro-Orifice Uniform Deposit Impactor, MOUDI）進行澆鑄現場逸散氣膠之濾紙分徑採集。採樣結束後，以濾紙稱量前後重量以計算採樣濃度及粒徑分佈狀況，並委由核能研究所以比例計數器（Proportional Counter）進行氣膠之總a、b放射性活度計量分析。而現場作業後進行清掃會造成沉積之微粒再懸浮於空氣中，是另一種暴露路徑來源，因此本研究搭配於鑄造現場收集澆鑄作業所沈積之氣膠，嘗試利用六階安德森採樣器（6-stage Anderson Impactor），進行正壓式氣膠再懸浮分徑收集，並將分徑後的氣膠微粒委由工業發展研究院以感應耦合電漿質譜儀（Inductively Coupled Plasma Mass Spectrometry, ICP-MS）進行重金屬成分分析。為了解鑄造廠逸散氣膠對於勞工之影響，研究中選用人體肺纖維母細胞（WI-38 cell），並依據勞工平均工作時數及潮氣體積等參數計算平均暴露劑量，進行MTT assay細胞毒性實驗。結果發現：在粒徑分布方面，鑄銅場和鑄鋁場皆有雙峰分布，鑄銅場之氣膠波峰粒徑約在截取粒徑1.8及5.6 μm，而鑄鋁場則約在截取粒徑1.8及18 μm以上；而單位氣膠重量所含之總a、b放射性活度最高處，在兩鑄造廠皆接近於小粒徑部分，尤其是在截取粒徑0.1∼0.32 μm範圍。而鑄銅場澆鑄區的氣膠，單位重量所含之金屬成分以Al、Si、Cu及Sr較高；而鑄鋁場澆鑄區的氣膠含有Al、Si及Sr較高。而WI-38之細胞暴露結果顯示，在低劑量濃度下，細胞存活率顯示細胞出現凋亡情形；然而在高劑量濃度暴露下，細胞存活率卻呈現增殖之情形。本研究最後以統計方法分析各影響因子之貢獻程度，及其是否具有顯著意義，發現微粒粒徑、劑量濃度、放射活度及重金屬成分對於人體肺細胞存活率皆有顯著相關性，然而各項暴露因子間存在共線性，在進行多變項邏輯回歸時會互相干擾而無法檢定，需要更進一步依其關連性進行分類，才能得到明確之結果。

關鍵字

澆鑄；氣膠；肺纖維母細胞；放射性活度

並列摘要

Casting process was indicated that easily to form the metal fumes and fugitive particle which was suspended in the metal foundry by the past literatures. However, the radioactivity of particulate characteristics was less Investigated. The effect of particulate characteristics with human, such as particle size, dose, concentration, radioactivity and heavy metal contribution were still unclear. For this reason, the research used the normal human lung fibroblast（WI-38 cells）to investigate the cytotoxicity from the particle sampled in the foundry by MTT assay. In addition, the research tries to clarify the contribution of each factor by statistical analysis. Two commercial foundries, copper or aluminum casting, were recruited in the research. A Micro-Orifice Uniform Deposit Impactor（MOUDI）was used to sample emission aerosols during casting processes. The filter papers were weighing to know the particle distribution in the foundry. Then, the measurement of total a and b radioactivity of aerosols had been carried out by using a proportional counter by Nuclear Energy Institute. Apart from this, particle responded in the air by clean the work site was another way which human exposure to the particle. The research try to use 6-stage Anderson Impactor with particle collected from casting work site to do positive-pressure re-suspension sizing. The sizing particle by this system was analyzed the heavy metal by Inductively Coupled Plasma Mass Spectrometry（ICP-MS） by Industrial Technology Research Institute. In order to clarify the particulate cytotoxicity by MTT assay, the study calculated the concentration that workers actually exposed to according to the average work time and tidal volume. The data of characteristics of particle and result of MTT assay were analyzed by statistics assay. The result show that based on cut off size of MOUDI, the two peaks of copper casting were 1.8 and 5.6 μm; on the other hand, the two peaks of aluminum casting were 1.8 and 18 ~ μm. Moreover, the peak aerosol total a and b radioactivity of the two casting foundries was in the range of 0.1∼0.32 μm. The major metal compositions of copper casting were Al, Si, Cu in order. Additionally, the major metal compositions of aluminum casting were Al, Si and Sr in order. The MTT assay result show that the WI-38 cells apoptosis in 1X dose level but proliferated in 10X dose level when exposed to casting emission aerosol. All the data were collected for statistics analysis; the study found that dose level, particle size, radioactivity and heavy metal were significantly related to the cell viability. However, the co-linearity in the exposed factors interfere the result to become none significantly by multivariate logistic regression assay. If the research wants to know the relationship of the exposed factors more clearly, it seems that the factors need further classified according to their related.

並列關鍵字

casting, aerosol ； WI-38 cell ； radioactivity

參考文獻

文永植 (2002). 微量元素與人體健康.

賴文龍微量元素對人體之健康.

Bursch, W., A. Ellinger, et al. (2000). "Programmed Cell Death (PCD): Apoptosis, Autophagic PCD, or Others?" Annals of the New York Academy of Sciences 926(1): 1-12.

Clift, M. J., B. Rothen-Rutishauser, et al. (2008). "The impact of different nanoparticle surface chemistry and size on uptake and toxicity in a murine macrophage cell line." Toxicol Appl Pharmacol 232(3): 418-427.

Fernández Espinosa, A. J., M. T. Rodrı́guez, et al. (2004). "Source characterisation of fine urban particles by multivariate analysis of trace metals speciation." Atmospheric Environment 38(6): 873-886.

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澆鑄作業逸散氣膠放射特性及細胞毒性之研究

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