Study On The Present Situation And Health Risk Of Desalinated Water In An Island County Of Zhejiang Province

Object:1.This study aims to understand the status of desalinated seawater used by residents of an island county in Zhejiang Province.To grasp the residents'understanding,attitudes and drinking situation of desalinated seawater,and to evaluate the satisfaction with the quality of desalinated seawater.2.To analyze the quality of desalinated seawater,and conduct health risk assessments for residents who have been drinking desalinated seawater,also to study the health risks and related factors of drinking desalinated seawater,then could provide evidences for strengthening the health monitoring and management of desalinated seawater.Methods:1.In this study,selected an island county in Zhejiang Province which used the desalinated seawater as the municipal water supply(hereinafter referred to as the island county),and an inland county with similar economic conditions and geographical location(hereinafter referred to as the control county)as the research sites.2.Survey of residents using desalinated seawater:data of demographic information,understanding,acceptability and drinking satisfaction of desalinated seawater,and etc.were collected through a self-designed questionnaire.3.Quality of desalinated seawater and health impacts assessment:(1)Desalinated seawater quality assessment:collected the two counties' routine water quality monitoring data of the product water and tap water from 2016 to 2018.Raw seawater,pretreated water,filtered water,product water and tap water were also collected from seawater desalination plant and tested respectively.(2)According to the model of the USNAS,the indicators of water quality difference between desalinated seawater and fresh water were assessted.(3)Investigated all primary schools,junior high schools and high schools with local people in island county,the growth and development indicators such as height and weight of students whose age were Between7 and 18 years were measured.4.Data collation and statistical analysis:established the database through EpiData3.1,and analyzed by SPSS 21.0.Kruskal-Wallis test was used to compare the data of water quality,t test was used to analysis the students' height and weight between the two groups.Matched Chi-square test was used to compare the preferences of water sources for different using purposes.Tests level are 0.05.Uncertainty analysis of health risk assessment was conducted by Oracle Crystal Ball software.LMS chartmaker 2.54 and LMS growth software were used to draw the growth curves.Results:1.Survey of residents using desalinated seawater:(1)residents have a low score for knowledge about desalinated seawater,and 77.6%(1468/1139)score less than 2 points.There was no significant difference in the distribution of the scores among different gender,age,educational level and years of residence(P>0.05),the respondents mainly obtained information by communicating with others.(2)30.9%(454/1 468)used desalinated water and other water sources(well water,etc.)as a drinking water source,and 9.7%(143/1 468)used desalinated water as the only source of water.49.96%(673/1 468)used desalinated seawater in cooking,and most of them tended to use desalinated seawater in personal cleaning(such as washing,bathing).There was significant difference in the use of desalinated seawater use between drinking water and personal cleaning(P<0.01).(3)76.7%(1 126/1 468)reported that they found color changes during the water supply process,more than half of the respondents occasionally found sediments in the water,and 36.2%thought that the taste of desalinated seawater needed to be improved.2.Desalinated seawater quality and health impacts assessment:(1)The indicators of desalinated seawater quality in the past three years,except for the fluctuation of the minimum value of pH,were relatively close.The boron content of desalinated seawater was high,and the total hazard index in the health risk assessment was 0.1048,which is within the maximum acceptable risk level.(2)There was no statistical difference in the distribution of height and weight between children and adolescents who drink and do not drink seawater desalinated water in island county.(3)The height and weight development level of students in island county were consistent with the national level.Conclusion:1.Residents of an island county in Zhejiang have one-sided understanding of desalinated seawater and have doubts about the hygienic and safety of water quality.And depending on the purpose of water use,the respondents have different preferences,the proportion of people using desalinated seawater for cleaning was significantly higher than that for drinking and cooking.Most people think that the sensory traits of desalinated seawater need to be improved.2.The boron content in desalinated water in the island county of Zhejiang was high,and the assessment results showed that its health risk was still within the acceptabler ange.Drinking desalinated seawater in this area did not affect the growth and development of children and adolescents.