Water Quality Evaluation And Health Risk Assessment Of Harvesting Vault Rainwater Source In The Southern Area Of Ningxia

Objective: To evaluate the water quality of harvesting vault rainwater source in thesouthern area of Ningxia, and realized the health problems though use the cellar, someindicators of health have risk assessment, to propose the simple and feasible preliminarydisinfection measures, then get a provision of reference to improve the and improve waterquality.Methods: In our study we adopted the combination of random and stratified samplingmethod, select90permanent residents long-term drinking rain water from the combination ofHaiyuan County, Yuanzhou and Xiji County three regions, and investigational by aself-designed questionnaire; Texting water quality divide into dry and wet season (180watersamples), evaluation some indicators of the test results use United States EnvironmentalProtection Agency (USEPA) risk assessment model recommended; Use chlorine dioxidesolution with different concentrations of rain water disinfection. After disinfection analysisthe total number of pit water results colonies, PH, disinfection byproducts (DBPs) chlorateand chlorite, chlorine dioxide and other indicators.Results:1.The Survey Results: there is74.4%with rain water as source to drinking inthe region,72.2%of the rainwater harvesting field for cement material,93.3%of theresidents gather in front of the preliminary pit water filtration,68.9%of residents weresatisfied with their drinking water status.2Water quality test results: rain water for180general percent of pass is42.8%. The lowest pass rate individual indicators was the totalnumber of colonies (68.3%), with a pass rate of comparison: the dry season> wet period, Haiyuan County> Yuanzhou> Xiji.3Disinfection results:30minutes chlorine dioxidedisinfection concentration of0.1mg/L could achieve the total number of bacterial indicatorsdecentralized water supply limits (<500CFU/100mL), disinfection byproducts chlorite andchlorate in drinking water in line with conventional indicators limits, but does not meet themargin of chlorine dioxide "drinking water health standards" disinfectant conventionalindicators and requirements;0.5mg/L chlorine dioxide disinfectant for30minutes to reachthe total number of bacteria in drinking water limit of conventional indicators (<100CFU/100mL), disinfection byproducts chlorite and chlorate in drinking water has reachedlimits of conventional indicators, and chlorine dioxide margin in line with "drinking waterhealth standards" disinfectant conventional indicators and requirements.4Health RiskAssessment Results: The area of lifelong non-carcinogenic health risk order: Fluoride> Pb>Hg> Mn> Fe> ammonia, are smaller than the International Commission on RadiologicalProtection (ICRP) recommended maximum acceptable value5.0×10-5, slightly dry seasonwet period, Yuanzhou> Xiji County> Haiyuan County; carcinogens sort of excess cancerrisk: arsenic> hexavalent chromium, are less than5.0×10-5, slightly dry season higher thanthe wet period, Xiji County> Yuanzhou> Haiyuan County.Conclusion:1Because of the water shortage drought in southern Ningxia, rain water canbe used supply for future residents of a certain period.2Residents’ lacks of health awarenessin the process use the water cellar management.3The water cellar qualified rate is low in thesouthern area of Ningxia, Main overweight indicators was microbiology, this means that mainhealth problem with rain water is excessive microbial indicators, such as the possibility ofhepatitis, dysentery and other waterborne outbreaks of infectious disease caused by a larger.4There was safety and effectively using0.1-0.5mg/L chlorine dioxide for disinfection routinein rain water, is desirable, but there are various disturbing factors to take into account thecellar, the authors recommend0.5mg/L II oxidized chlorine as routine disinfection of watercellars in the region more secure manner.5Non-carcinogenic health risk and excess lifetime risk of cancer in the area of carcinogens caused by the drinking water were lower than themaximum acceptable values, the risk of carcinogens than non-carcinogens, the higherthe risk of the value of fluoride in some areas should increase efforts to change the water toreduce fluoride works.