How clean is the average backyard pool is? Find out on this Moment of Science.
Everybody loves the swimming pool. But how clean is the water in the average backyard or public pool? If you trust (1)chlorine to take care of germs, you’re in for a surprise.
Chlorine and other (2)disinfectants do indeed help to clean the water, but some germs can survive in even the best-kept pool. For example, (3)cryptosporidium may live in pool water for several days. Crypto causes a (4)diarrheal illness and may (5)rinse off the bodies of infected people or (6)diapered children into the pool. If you swallow infected pool water, you may become sick.
Other germs may live for a few minutes or a few hours in a chlorinated pool: Giardia(鞭毛虫), Shigella(志贺氏菌), and E. Coli(大肠杆菌) may cause diarrheal illnesses. Pseudomonas Aeruginosa(绿脓杆菌) may cause an ear infection called swimmer’s ear and also a skin infection called “hot tub rash(热浴池皮疹),” that is usually associated with very warm pools and spas.
While keeping the correct chlorine and ph levels will minimize (7)water-borne illness, prevention is also a good idea. Keep diapered children in the water for only brief periods and keep sick people out of the water altogether. And, don’t ever swallow pool water.
译文：
和细菌游泳
每个人都喜欢游泳池。但是在一般的后院和游泳池的水有多清洁呢?如果你相信氯可以制服细菌，那么接下来的就会让你惊奇。
氯和其它的消毒剂的确有助于清洁水，但是一些细菌在保护很好的水池里仍然可以存活。列如：隐孢子虫可能在池水中生活很多天。隐孢子虫能引起腹泻，并且会从进入泳池的被感染病人或者带尿布孩子的身上被冲刷下来。如果你吞下被感染的池水，也会生病。
其它的细菌可能在氯化池里生存几分钟或者几个小时：鞭毛虫，志贺氏菌，和大肠杆菌可能引起腹泻。绿脓杆菌可能引起游泳性耳炎的耳朵感染以及热浴池皮疹的皮肤感染。热浴池皮疹通常与非常温暖的水池和温泉有关。
尽管保持正确的氯和pH值能够减少通过水传播的疾病，可是预防也是一个好主意。保持仍带尿布的孩子在水中只停留短暂的时间，使病人远离水。并且永远不要吞下池水。
