Swimming pools adopt chlorination to ensure microbial safety.Giardia has attracted atten-tion in swimming pool water because of its occurrence,pathogenicity,and chlorine resis-tance.To control Giardia concentrations in pool water and reduce the microbial risk,higher chlorine doses are required during disinfection.Unfortunately,this process produces car-cinogenic disinfection byproducts that increase the risk of chemical exposure.Therefore,quantitatively evaluating the comparative microbial vs.chemical exposure risks that stem from chlorination inactivation of Giardia in swimming pool water is an issue that demands attention.We simulated an indoor swimming pool disinfection scenario that followed com-mon real-world disinfection practices.A quantitative microbial risk assessment coupled with a chemical exposure risk assessment was employed to compare the Giardia microbial exposure risk(MER)and the trihalomethane chemical exposure risk(CER)to humans.The results demonstrated a 22％decrease in MER-and CER-induced health exposure risk,from 8.45E-5 at 8:00 to 6.60E-5 at 19:00.Both the MER and CER decreased gradually,dropping to 3.26E-5 and 3.35E-5 at 19:00,respectively.However,the CER exceeded the MER after 18:30 and became the dominant factor affecting the total exposure risk.Past the 18 hr mark,the contribution of trihalomethane CER far exceeded the risk aversion from microbial inactiva-tion,leading to a net increase in total exposure risk despite the declining MER.Swimmers may consider swimming after 19:00,when the total exposure risk is the lowest.Lowering water temperature and/or pH were identified as the most sensitive factors to minimize the overall health exposure risk.

Chenyue Yin;Bingjun Liu;Kyu Hur;Shengkun Dong

Guangdong Engineering Technology Research Center of Water Security Regulation and Control for Southern China,Guangzhou 510275,China;Southern Laboratory of Ocean Science and Engineering,School of Civil Engineering,Sun Yat-Sen University,Zhuhai 519000,China;Shinohara Nishicho,Kohoku Ward,Yokohama,Kanagawa 222-0025,Japan

环境科学学报（英文版）

[1]Chenyue Yin;Bingjun Liu;Kyu Hur;Shengkun Dong-.Assessing microbial and chemical exposure risks of Giardia in indoor swimming pool water disinfected by chlorine)[J].环境科学学报（英文版）,2022(07):276-284

disinfected,cinogenic,trihalomethane,60E,26E,35E,Swimmers

Assessing,microbial,chemical,exposure,risks,Giardia,indoor,swimming,water,chlorine,Swimming,pools,adopt,chlorination,ensure,safety,has,attracted,because,its,occurrence,pathogenicity,resis,tance,To,control,concentrations,reduce,higher,doses,required,during,disinfection,Unfortunately,this,process,produces,car,byproducts,that,increase,Therefore,quantitatively,evaluating,comparative,stem,from,inactivation,issue,demands,attention,We,simulated,scenario,followed,real,world,practices,assessment,coupled,was,employed,compare,MER,CER,humans,results,demonstrated,induced,health,45E,Both,decreased,gradually,dropping,respectively,However,exceeded,after,became,dominant,affecting,total,Past,hr,mark,contribution,far,aversion,leading,net,despite,declining,may,consider,when,lowest,Lowering,temperature,were,identified,most,sensitive,factors,minimize,overall

0.444375