Fluoride and nitrate enriched groundwater are potential threats to the safety of the groundwater supply that may cause significant effects on human health and public safety,especially in aggregated population areas an...Fluoride and nitrate enriched groundwater are potential threats to the safety of the groundwater supply that may cause significant effects on human health and public safety,especially in aggregated population areas and economic hubs.This study focuses on the high F^(−)and NO_(3)^(−)concentration groundwater in Tongzhou District,Beijing,North China.A total of 36 groundwater samples were collected to analyze the hydrochemical characteristics,elucidate genetic mechanisms and evaluate the potential human health risks.The results of the analysis indicate:Firstly,most of the groundwater samples are characterized by Mg-HCO_(3) and Na-HCO_(3) with the pH ranging from 7.19 to 8.28 and TDS with a large variation across the range 471-2337 mg/L.The NO_(3)^(−)concentration in 38.89%groundwater samples and the F^(−)concentration in 66.67%groundwater samples exceed the permissible limited value.Secondly,F^(−)in groundwater originates predominantly from water-rock interactions and the fluorite dissolution,which is also regulated by cation exchange,competitive adsorption of HCO_(3)−and an alkaline environment.Thirdly,the effect of sewage disposal and agricultural activities have a significant effect on high NO3-concentration,while the high F^(−)concentration is less influenced by anthropogenic activity.The alkaline environment favors nitrification,thus being conducive to the production of NO_(3)^(−).Finally,the health risk assessment is evaluated for different population groups.The results indicate that high NO_(3)^(−)and F^(−)concentration in groundwater would have the largest threat to children’s health.The findings of this study could contribute to the provision of a scientific basis for groundwater supply policy formulation relating to public health in Tongzhou District.展开更多
Electrochemical etching of titanium alloy in a fluoride-containing electrolyte results in ordered nanotextured surfaces. The reproducibility of nanotextured surfaces depends on several process parameters, most notably...Electrochemical etching of titanium alloy in a fluoride-containing electrolyte results in ordered nanotextured surfaces. The reproducibility of nanotextured surfaces depends on several process parameters, most notably the fluoride ion concentration in the electrolyte. In the present work, electrochemical etching of Ti6Al4V alloy foils in ethylene glycol containing 0.66 wt% NH4F and 2% deionized water was carried out at 60 V for 45 minutes. This paper describes the depletion of fluoride ion concentration and contamination of electrolyte upon reuse. Inductively coupled plasma-optical emission spectroscopy was used to measure the dissolution of metal oxides in the electrolyte during etching. We found increasing concentration of the alloy elements Ti, Al, V contaminated the electrolyte due to repeated reuse of the electrolyte. The results show an appreciable log-linear depletion of fluoride ion concentration resulting in a changed surface morphology, chemical composition and etched volume. This paper provides an important insight to changes in surface morphology and surface chemistry with extended reuse of the etching electrolyte, useful for regulatory approvals.展开更多
Objective To investigate the influencing factors of adult dental fluorosis in drinking water-borne endemic fluorosis areas of Inner Mongolia Autonomous Region.Methods A case-control study was conducted in January 2024...Objective To investigate the influencing factors of adult dental fluorosis in drinking water-borne endemic fluorosis areas of Inner Mongolia Autonomous Region.Methods A case-control study was conducted in January 2024 to select adult fluorosis patients(case group)and healthy individuals(control group)from the drinking water-borne endemic fluorosis areas in Helinger County,Hohhot City,Inner Mongolia Autonomous Region as the surveysubjects.Urinesamples were collected to determine urinary fluoride concentration.A questionnaire survey was conducted.SPSS 25.0 software was used for X?test and multivariate logistic regression analysis.2 Restricted cubic spline(RCS)was used to analyze the association between urinary fluoride concentration and the risk of dental fluorosis in adults.Results A total of 161 individuals were included in the survey,including 100 in the case group and 61 in the control group.The results of univariate analysis showed that there were statistically significant differences in the distribution of gender,smoking,and urinary fluoride concentration between the case group and the control group(x^(2)=7.54,5.02,9.69,P<0.05).The results of multivariate logistic regression analysis indicated that gender(OR=0.36,95%CI:0.18-0.73,P=0.005)and urinary fluoride concentration(0R=3.08,95%CI:1.46-6.67,P=0.003)were the influencing factors of adult fluorosis.RCS analysis showed a significant linear dose-response relationship between the risk of dental fluorosis and urinary fluoride concentration(P_(overall tend)=0.001,P_(overall tend)=0.071).When the urinary fluoride concentration was greater than 1.57 mg/L,the risk of dental fluorosis increased with the increase of urinary fluoride concentration.Conclusion Gender and urinary fluoride concentration are the risk factors of dental fluorosis in adults in drinking water-borne endemic fluorosis areas of Inner Mongolia Autonomous Region.展开更多
基金supported by the project of China Geological Survey(Grant No.DD20221677-2)the fundamental research funds of Chinese Academy of Geological Sciences Basal Research Fund(Grant No.JKYQN202307).
文摘Fluoride and nitrate enriched groundwater are potential threats to the safety of the groundwater supply that may cause significant effects on human health and public safety,especially in aggregated population areas and economic hubs.This study focuses on the high F^(−)and NO_(3)^(−)concentration groundwater in Tongzhou District,Beijing,North China.A total of 36 groundwater samples were collected to analyze the hydrochemical characteristics,elucidate genetic mechanisms and evaluate the potential human health risks.The results of the analysis indicate:Firstly,most of the groundwater samples are characterized by Mg-HCO_(3) and Na-HCO_(3) with the pH ranging from 7.19 to 8.28 and TDS with a large variation across the range 471-2337 mg/L.The NO_(3)^(−)concentration in 38.89%groundwater samples and the F^(−)concentration in 66.67%groundwater samples exceed the permissible limited value.Secondly,F^(−)in groundwater originates predominantly from water-rock interactions and the fluorite dissolution,which is also regulated by cation exchange,competitive adsorption of HCO_(3)−and an alkaline environment.Thirdly,the effect of sewage disposal and agricultural activities have a significant effect on high NO3-concentration,while the high F^(−)concentration is less influenced by anthropogenic activity.The alkaline environment favors nitrification,thus being conducive to the production of NO_(3)^(−).Finally,the health risk assessment is evaluated for different population groups.The results indicate that high NO_(3)^(−)and F^(−)concentration in groundwater would have the largest threat to children’s health.The findings of this study could contribute to the provision of a scientific basis for groundwater supply policy formulation relating to public health in Tongzhou District.
文摘Electrochemical etching of titanium alloy in a fluoride-containing electrolyte results in ordered nanotextured surfaces. The reproducibility of nanotextured surfaces depends on several process parameters, most notably the fluoride ion concentration in the electrolyte. In the present work, electrochemical etching of Ti6Al4V alloy foils in ethylene glycol containing 0.66 wt% NH4F and 2% deionized water was carried out at 60 V for 45 minutes. This paper describes the depletion of fluoride ion concentration and contamination of electrolyte upon reuse. Inductively coupled plasma-optical emission spectroscopy was used to measure the dissolution of metal oxides in the electrolyte during etching. We found increasing concentration of the alloy elements Ti, Al, V contaminated the electrolyte due to repeated reuse of the electrolyte. The results show an appreciable log-linear depletion of fluoride ion concentration resulting in a changed surface morphology, chemical composition and etched volume. This paper provides an important insight to changes in surface morphology and surface chemistry with extended reuse of the etching electrolyte, useful for regulatory approvals.
文摘Objective To investigate the influencing factors of adult dental fluorosis in drinking water-borne endemic fluorosis areas of Inner Mongolia Autonomous Region.Methods A case-control study was conducted in January 2024 to select adult fluorosis patients(case group)and healthy individuals(control group)from the drinking water-borne endemic fluorosis areas in Helinger County,Hohhot City,Inner Mongolia Autonomous Region as the surveysubjects.Urinesamples were collected to determine urinary fluoride concentration.A questionnaire survey was conducted.SPSS 25.0 software was used for X?test and multivariate logistic regression analysis.2 Restricted cubic spline(RCS)was used to analyze the association between urinary fluoride concentration and the risk of dental fluorosis in adults.Results A total of 161 individuals were included in the survey,including 100 in the case group and 61 in the control group.The results of univariate analysis showed that there were statistically significant differences in the distribution of gender,smoking,and urinary fluoride concentration between the case group and the control group(x^(2)=7.54,5.02,9.69,P<0.05).The results of multivariate logistic regression analysis indicated that gender(OR=0.36,95%CI:0.18-0.73,P=0.005)and urinary fluoride concentration(0R=3.08,95%CI:1.46-6.67,P=0.003)were the influencing factors of adult fluorosis.RCS analysis showed a significant linear dose-response relationship between the risk of dental fluorosis and urinary fluoride concentration(P_(overall tend)=0.001,P_(overall tend)=0.071).When the urinary fluoride concentration was greater than 1.57 mg/L,the risk of dental fluorosis increased with the increase of urinary fluoride concentration.Conclusion Gender and urinary fluoride concentration are the risk factors of dental fluorosis in adults in drinking water-borne endemic fluorosis areas of Inner Mongolia Autonomous Region.
