工業用冷卻水塔水中嗜肺性退伍軍人菌測定

Measurements of Legionella pneumophila in Water of Industrial Cooling Towers

本研究針對工業用冷卻水塔水中嗜肺性退伍軍人菌孳生情形進行調查和測定，以瞭解工業用冷卻水塔受嗜肺性退伍軍人菌污染狀況，及各事業單位對於預防冷卻水塔受嗜肺性退伍軍人菌污染所採取的滅菌措施。本研究一共於 82 個廠區，採集 132 工業用冷卻水塔水樣進行檢測。濾膜法和定量聚合脢連鎖反應（Polymerase Chain Reaction, PCR）檢測法用以分析檢測退伍軍人菌和嗜肺性退伍軍人菌的存在和數量。另以問卷調查事業單位工業用冷卻水使用狀況、冷卻水系統維護情形、冷卻水水體特性測定，及冷卻水塔清潔及消毒現況。從所採集的冷卻水水樣分析檢測結果發現：嗜肺性退伍軍人菌在濾膜法和定量PCR法的孳生率分別為19%（25/132）和59%（78/132）。定量PCR法所檢測出的嗜肺性退伍軍人菌菌數平均值（±標準差）為 68,118（±338,779）CFU/100mL，中位數為 27 CFU/100mL。水質特性（pH 值、溶氧、餘氯和水溫）僅發現水中餘氯量和嗜肺性退伍軍人菌的孳生情形有關聯（χ 2 =8.72, p-value < 0.01） ，冷卻水系統的維護狀況，以生垢和水藻孳生與退伍軍人菌的檢出率有相關。由於冷卻水系統產生水霧的情形相當普遍（約 49%） ，為預防人員於工作場所感染嗜肺性退伍軍人菌，對於工業用冷卻水塔嗜肺性退伍軍人菌孳生的問題，應採取適當的控制與管理。

The growth of Legionella pneumophila in industrial cooling towers were investigated and measured to find out the situation of the contamination problem. The control approaches used by industries were also surveyed. A total of 132 water samples from the cooling towers in 82 different plants were examined. Both membrane filtration method and quantitative polymerase chain reaction (PCR) method were developed to examine the existence of Legionella spp. and L. pneumophila and quantify their concentrations in the water samples. A questionnaire was designed to collect the information of the usage of industrial cooling water, the maintenance of the cooling towers, the quality of industrial cooling waters, and the cleaning disinfection of the industrial cooling towers. The results showed that the contamination rates of L. pneumophila for the water samples were 19%(25/132) and 59%(78/132) based on membrance filteration and quantitative PCR methods, respetively. The mean (± standard deviation) of L. pneumophila of the water samples measured by quantitative PCR method was 68,118(±338,779) CFU/100mL and median 27 CFU/100mL. Only the concentration of residual choline of the characteristics of water quality (pH, dissoloved oxygen, residual choline and water temperature) was found to have an influence on the contamination of L. pneumophila to the cooling water systems (χ2=8.72, p-value < 0.01). Regarding the maintenance status of cooling water systems, the appearance of sacle and the growth of algae were associated with the contamination of L. pneumophila. Since the generation of water mists under the operation of cooling water systems was common (about 49%), the problem of the contamination of L. pneumophila to the industrial cooling water systems should be controlled and managed to prevent the workers’ infection of L. pneumophila in the work environments.