Study On The Exposure Characteristics Of Chloramine In Indoor Swimming Pool And Countermeasures Of Exercise

Objective: Chlorine-based disinfectants are usually applied to kill microorganisms in swimming pools.However,it can combine with organic or inorganic nitrogen compounds released from the human body and form chloramines(CAMs).CAMs are not only harmful to the human bodys,but also participate in the formation of other nitrogen-containing disinfection by-products,which can affect human health seriously.Here,we detected the content of CAMs,free chlorine(FCl),and ammonia nitrogen(AN)in autumn and summer water samples in an indoor swimming pool of Taiyuan city,and analyzed the spatial-temporal characteristics of CAMs,FCl and AN,which can provid rationalization proposal for swimmers to select the time and location;we also analyzed the correlation relationships between CAMs,FCl,AN and other environmental factors,which can provide the effective treatment measures for water quality health of swimming pools.Methods: water samples were collected from an indoor swimming pool of Taiyuan city in autumn and summer.The content of CAMs,FCl and AN in different times(seasons,24h)and locations(shallow area,deep area)of the swimming pool were measured by spectrophotometric method.Some environmental factors including p H,room temperature(T),relative air humidity(H),and the cumulative number of swimmers(P)were also recorded.R,Origin,SPSS,Graph Pad softwares were used to analyze the Spatial-temporal variations characteristics of CAMs,FCl,AN and the correlation relationship of these three parameters with the environmental factors.Results:(1)Of the 8 shallow area samples in autumn,three p Hs exceeded the standard,four H exceeded standard;of the 8 deep area samples,two p H exceeded the standard and four H exceeded standard;while the T were in the normal range both in deep and shallow area;of the 22 shallow area samples in summer,three p Hs exceeded the standard;while the p H and T were in the normal range of the 22 deep area samples;H exceeded the standard both in deep and shallow area samples.(2)Our results showed that the content of CAMs in autumn ranged from 0 to1.474mg/l,FCl from 0.279 to 6.195 mg/l,and AN from 0.011 to 0.246 mg/l.The levels of CAMs in the deep area in the morning were significantly higher than that in the afternoon(p < 0.05).Our results showed that the content of CAMs in summer ranged from 0 to 0.224 mg/l,FCl from 0.027 to 0.379 mg/l,and AN from 0.075 to 1.22 mg/l.The levels of FCl in the deep area in the morning were significantly higher than that in the afternoon(p < 0.05).At the four time points in summer,the levels of CAMs at night and afternoon was significantly higher than that in the morning both in deep and shallow area(p <0.05).(3)We found that in autumn,CAMs had a negative correlation with FCl,FCl had a positive correlation with H and p H,AN had a negative correlation with p H,CAMs had no correlation with AN;While in summer,CAMs showed a positive correlation with H and P,FCl showed a negative correlation with AN,CAMs and P;CAMs had no correlation with AN.Conclusion:(1)Our results showed that the content of CAMs in the autumn morning is significantly higher than that in the afternoon and the content of CAMs in the summer night and afternoon is significantly higher than that in the morning.Therefore,it is better to choose afternoon in autumn or morning in summer,which could protect the health of swimmers to effectively avoid the peak period of CAMs.(2)CAMs had a negatively correlated with FCl,and positively correlated with H and P,which suggested that disinfection method of fold point chlorination or improvement the ventilation and dehumidification capacity can be considered to reduce the generation of CAMs in swimming pools.