| 摘要: | 本研究以國內某一使用金屬加工液之工廠為例，評估其使用金屬加工液造成作業環境空氣中之細菌生物氣膠濃度及細菌菌種分佈特性，並利用Biosampler及MAS-100生物氣膠採樣器來進行作業現場之空氣微生物採樣。
結果發現在新鮮的金屬加工液中的細菌濃度低於20 CFU/mL，而使用過的金屬加工液最高可含有1.1×107 CFU/mL的細菌濃度。在更新金屬加工液後，在距離切削機台0.5公尺、1.5公尺及3公尺的空氣中分別有1.0×104、1.6×104及5.3×103 CFU/m3的細菌濃度存在。在金屬加工液使用二天後，則有4.1×105、3.3×105及2.5×105 CFU/m3的細菌濃度。經過三天的操作並加入部分新鮮的金屬加工液後，會有1.5×105、5.2×104及8.1×104 CFU/m3的細菌濃度。經過五天後，則空氣中的細菌濃度會達到1.1×106、8.7×105及 1.8×106 CFU/m3。
在空氣中可鑑定出來的菌種有Ralstonia pickettii、Actinomyces neuii ssp anitratus、Aeromonas hydrophila group 2、Arcanobacterium haemolyticum、Bacillus coagulans、B. licheniformis、B. pumilus、B. sphaericus、B. stearothermophilus、B. thuringiensis、Brevibacillus brevis、Brevibacterium spp.、Burkholderia cepacia、Cellulomonas spp.、Corynebacterium aquaticum、C. minutissimum、C. urealyticum、Flavimonas oryzihabitans、Micrococcus spp.、Oerskovia turbata、O. xanthineolytica、Serratia marcescens、Staphylococcus capitis、S. epidermidis、S. lentus、S. xylosus等菌種。而在空氣可鑑定出最多的菌種是Ralstonia pickettii (93.6~100%)，此菌種在1993年之前是稱為Pseudomonas pickettii。
在結論方面可發現 (1)研究結果發現原本不含菌之金屬加工液，在使用後會產生大量細菌。在金屬加工液中會有2.4×104 CFU/mL ~ 1.7×108 CFU/mL 的細菌會存在。(2)受污染之金屬加工液可能會因切削作業而變成氣膠散佈至空氣中，而使空氣中也含有高濃度之細菌生物氣膠，因此距離切削機台0.5、1.5及3公尺的空氣中可測量到大量之細菌濃度，濃度範圍為5.3×103 CFU/m3 ~ 1.1×106 CFU/m3。(3) 可以發現金屬加工液使用的時間越長，在金屬加工液中所含的細菌菌落濃度越高，而在靠近切削機台的0.5公尺、1.5公尺及3公尺採樣點所採集到的細菌菌落濃度也越高。(4)可以發現在切削機台附近發現大量的革蘭式陰性桿菌的存在，如Ralstonia pickettii等菌種存在。
為了要減少空氣中的細菌濃度，建議要增加更換金屬加工液的頻率及在更新金屬加工液前要徹底的清潔機台，包括管線中的金屬加工液都要清潔。
This study was to investigate the characteristics of bioaerosols associated with metalworking fluids (MWFs) at a metal cutting factory in Taiwan. The concentrations and identification of bacteria both in the air and in the MWFs were measured. Bioaerosol samples were collected by Biosamplers and MAS-100 samplers. It was found that the bacterial concentrations in the fresh and used MWFs were below 20 CFU/mL and as high as 1.1×107 CFU/mL, respectively. In a factory, when fresh MWFs were used, the airborne bacterial concentrations at 0.5, 1.5 and 3 m away from a metal-working machine were 1.0×104, 1.6×104, and 5.3×103 CFU/m3, respectively. After 2-day operation, the bacterial concentrations increased as much as 4.1×105, 3.3×105, and 2.5×105 CFU/m3, respectively. After 3-day operation, some fresh MWFs were added, and the bacterial concentrations became 1.5×105, 5.2×104, and 8.1×104 CFU/m3, respectively. After 5-day operation, the bacterial concentrations became as high as 1.1×106, 8.7×105, and 1.8×106 CFU/m3, respectively. The bacterial bioaerosols were found to be Ralstonia pickettii, Actinomyces neuii ssp anitratus, Aeromonas hydrophila group 2, Arcanobacterium haemolyticum, Bacillus coagulans, B. licheniformis, B. pumilus, B. sphaericus, B. stearothermophilus, B. thuringiensis, Brevibacillus brevis, Brevibacterium spp., Burkholderia cepacia, Cellulomonas spp., Corynebacterium aquaticum, C. minutissimum, C. urealyticum, Flavimonas oryzihabitans, Micrococcus spp., Oerskovia turbata, O. xanthineolytica, Serratia marcescens, Staphylococcus capitis, S. epidermidis, S. lentus, S. xylosus. The most predominant bacterium was Ralstonia pickettii (93.6~100%) which used to be Pseudomonas pickettii before 1993. In conclusion, (1) The range of bacteria in the MWFs : 2.4×104 ~ 1.7×108 CFU/mL, (2) The range of bacteria in the air : 5.3×103 ~ 1.1×106 CFU/m3, (3) Both of bacterial concentrations in the MWF and air increased with the age of MWF. (4) The most predominant bacterium in the air was Ralstonia pickettii. In order to decrease the bioaerosol concentrations, it should be better to increase the frequency of replacement of used MWFs and to clean the piping before fresh MWFs were added. |
