游泳池池水中消毒副產物生成特性之探討

Abstract

游泳池池水消毒可以維護游泳池水不受到病原體的汙染，以保護泳客健康。然而，池水中的消毒劑卻會和入水中各種有機物質反應(包括泳客的毛髮、使用的乳液、化妝品、排出的汗液及尿液等)，生成所謂的消毒副產物。現今關切的消毒副產物包括三鹵甲烷 (Trihalomethanes, THMs)、含鹵乙酸 (Haloacetic acids, HAAs)，以及N-亞硝基二甲基胺 (N-nitrosodimethylamine,NDMA)等。已經有許多的研究這些消毒副產物會對人體健康有負面的影響。 為了瞭解游泳池水中消毒副產物的生成特性，本研究選取臺北市五個不同類型的游泳池做為研究對象，進行一日三次的採樣，以了解一天內泳池水質及消毒副產物的濃度變化。而為了深入探討含溴鹵乙酸 (Brominated HAAs, Br-HAAs)及含溴三鹵甲烷 (Brominated THMs, Br-THMs)在泳池水中的生成狀況，亦進行池水消毒副產物生成潛能實驗。此外，為了瞭解臭氧與加氯消毒對HAAs及THMs的生成影響，利用模擬實際泳池消毒方式的實驗，以觀察臭氧對兩種消毒副產物影響。最後，利用氯胺消毒方式以探討游泳池水中可能生成NDMA的可能性。 研究結果發現，泳客人數變多，泳池中的消毒副產物也會跟著增加，特別是不具揮發性的HAAs。無論何種類型的游泳池，夏天的THMs及HAAs濃度都比冬天高出許多(夏天：HAAs 90.98-296.52 μg/L，THMs 28.07-85.24 μg/L；冬天：HAAs 51.24-149.55 μg/L，THMs 3.85-19.61 μg/L)。由於游泳池水中之有機污染物多數都是來自泳客排出之生物性汙染物，一般泳池水中HAAs濃度均比THMs高。研究結果顯示Br-HAAs濃度可以用來代表池水受到人體帶入物質汙染程度的參考參數。臭氧處理雖能夠有效降低池水中的THMs，但對降低HAAs濃度卻無顯著效果。經過臭氧處理過後的泳池水，也會增加生成NMDA濃度的潛能。然而隨著池水與臭氧接觸時間的增加，NDMA的生成濃度也會跟著減少。研究也發現，過濾處理對於消毒副產物的生成有一定的影響，未經過過濾的池水產生消毒副產物的濃度比較高 (有過濾的池水生成：HAAs 64.00 -91.24 μg/L，THMs 5.09-16.83 μg/L；未過濾的池水生成：HAAs 64.00-94.30 μg/L，THMs 16.40-27.59 μg/L )。 本研究經由長時間調查游泳池水的水質狀況，並針對THMs和HAAs變化做觀察；過去研究多為針對THMs，極少是針對HAAs作探討。另外，本研究也首度探討臭氧處理對NMDA在游泳池水中生成的影響。

Chlorination of swimming pool water is an indispensable process to maintain the water quality for prevention of potential health problems. However, the disinfectants react with bather loads (matters carried by the swimmers into the swimming pool water, such as lotions, hair, makeup, sweat, urine. etc), and these reactions produce various contaminants including disinfection by- products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs) and nitrosodimethylamine (NDMA). Previous studies have shown that DBPs are carcinogens, which may have adverse health impacts to the swimmers. To gain a better understanding of DBPs in pool water, five swimming pools with different types of operations were selected and sampled to assess the relationships between the water qualities, disinfection practices and formation of DBPs. In order to investigate the DBPs concentration change during a day, a whole day sampling of one swimming pool had also been conducted. The DBPs formation potential tests were also conducted to assess the formation of brominated HAAs and THMs formation in pool water. Moreover, a pilot-experiment of ozone treatment and chlorination disinfection was conducted to evaluate the effects of ozonation on the formation of THMs and HAAs. Lastly, chloramination of pool water was investigated to assess the NDMA formation potential. The results had showed that the DBPs in pool water increased with the number of swimmers, especially the non-volatile HAAs. A higher level of THMs and HAAs was observed in pool water during summer season (HAAs: 90.98-296.52 μg/L; THMs: 28.07-85.24 μg/L), and their levels were apparently decreased in winter (HAAs: 51.24-149.55 μg/L; THMs: 3.85-19.61 μg/L). The presence of higher Br-HAAs concentrations could be a representative parameter to express the contaminated with more of the human substances. Ozone treatment could effectively decrease the THMs in pool water, but the removal of HAAs was poor. The concentration of NDMA would increase after the pool water had been treated with ozone, which might be attributed to the release of more precursors from ozonated impurities, but after increase the contact time with ozone, the level of NDMA was decreased. Continuous filtration of pool water has impact on DBPs formation: it was observed that filtered pool water showed lower level of DBPs formation than the non-filtered pool water (DBPs formation of filtered pool water: HAAs 64.00-91.24 μg/L, THMs 5.09-16.83 μg/L; DBPs formation of non-filtered pool water: HAAs 64.00-94.30 μg/L, THMs 16.40-27.59 μg/L ). This study had done a long-term investigation to the water quality and two DBPs (HAAs and THMs) in pool water. Furthermore, this study is also the first study in Taiwan to investigate the relation of ozone treatment and DBPs formation in pool water.