Objective To understand the qualified situation and change trend of fluoride content in drinking water in Chengde,so as to provide a scientific foundation for safeguarding residents'health and optimizing water treatment processes in water plants.Methods Samples were collected and tested at Chengde's monitoring sites during dry and wet seasons from 2020 to 2021.The fluoride qualified rates were compared and analyzed based on different years,water period types,water source types,treatment methods,water source depths,and water supply methods.The collection,storage,transportation,and detection of water samples adhered strictly to national standards.Categorical variables were described using proportions,and comparison between groups were conducted using the Chi-square test and Fisher exact probability method.The concentration of fluoride in water across different years was assessed for normal distribution using the Kolmogorov-Smirnov(K-S)test method.Results From 2020 to 2021,a total of 2 386 water samples were tested in Chengde,with an overall fluoride qualified rate of 98.91％.The fluoride concentration ranged from 0.10 to 6.47mg/L,with a median of 0.34mg/L.The K-S test indicated a non-normal distribution of superscalar.Chi-square test results revealed a statistically significant difference in fluoride qualified rates for water samples from different years(x2=7.598,P=0.006),showing an increasing trend.There was no statistically significant difference in fluoride qualified rates between dry and wet seasons(x2=0.622,P=0.430)from 2020 to 2021.Fisher exact probability method indicated that groundwater fluoride qualified rates were lower than surface water(P=1.000).No statistically significant difference was found in fluoride qualified rates among different water treatment methods(x2=2.391,P=0.495).The lowest fluoride qualified rate was observed in water after disinfection treatment at 98.58％.There was a statistically significant difference in fluoride qualified rates based on water source depth(x2=97.542,P＜0.001),with spring water having the lowest qualified rate at 90.00％.There was no statistically significant difference in the fluoride qualified rate between water qualified rate of different water supply methods(x2=7.591,P=0.108),with urban self-built facilities water supply having the lowest qualified rate at 98.44％.Conclusion Chengde exhibits a high fluoride qualified rate in water quality,indicating the effectiveness of water improvement and fluoride reduction projects.It is recommended to continue implementing effective fluoride reduction measures,with a focus on water source selection and advancing water treatment technology as practical measures to ensure drinking water safety.
Drinking waterFluoride indexMonitoring analysisDry seasonWet season
NETL
NSTL
万方数据
