Objective:To learn about the monitoring indicators and patient management in coal-burning-borne endemic arsenic poisoning areas in Shaanxi Province, and provide a basis for consolidating and improving the prevention and control achievements.Methods:From March to December 2023, in accordance with the requirements of the "Notice of the Office of Shaanxi Provincial Health Commission on Issuing of the Monitoring Plan for Key Endemic Diseases Such as Kashin-Beck Disease" and "The Monitoring Plan for Endemic Fluorosis and Arsenic Poisoning in Shaanxi Province", a basic situation investigation was conducted in the affected villages of all counties (districts) with coal-burning-borne endemic arsenic poisoning in Shaanxi Province, and on-site visits were conducted to check the management of high arsenic coal mines. Using the simple random sampling method, 30 families in each village were selected to investigate the use of stoves and the formation of health-related behaviors. A survey on arsenic poisoning was carried out among all populations in the affected villages. According to the requirements of the provincial monitoring program, 720 people were randomly selected from 12 affected villages in 3 monitoring counties to measure their urinary arsenic level. The determination was based on the "Guidelines for the Safety of Urinary Arsenic in Population" (WS/T 665-2019). The evaluation for elimination of disease areas was carried out in accordance with the "National Health Commission Issued the Evaluation Approach for Control and Elimination of Priority Endemic Diseases (2019 edition)".Results:A total of 2 cities, 8 counties (districts), 99 townships, and 1 414 affected villages were monitored. All 53 high arsenic coal mines had stopped mining. The rate of qualified improved stoves was 99.97%; the correct utilization rate of qualified improved stoves, and the correct drying rate of corn and chili peppers provided for human consumption in the affected villages were 100.00%. A total of 2 064 138 people were examined, and 2 682 cases of arsenic poisoning were detected, all of whom were historical patients. There were no new cases of arsenic poisoning or skin cancer. There were currently 2 682 arsenic poisoning patients who had received family doctor contract services and implemented follow-up management. The geometric mean of urinary arsenic was 0.016 7 mg/L, which was lower than the safety guideline value for human urinary arsenic (0.032 mg/L).Conclusions:The monitoring indicators in the coal-burning-borne endemic arsenic poisoning areas in Shaanxi Province have reached the elimination standards. In the future, we should continue to strengthen the management of high arsenic coal mines, implement comprehensive prevention and control measures mainly focused on furnace and stove renovation and health promotion, and do a good job in patient management to continuously consolidate and improve the prevention and control achievements.

Objective:To learn about the operation of fluoride reduction and water improvement projects, the current situation of water fluoride level and the changing trend of fluorosis in drinking water-borne endemic fluorosis areas in Shaanxi Province, and to evaluate the effect of prevention and control measures.Methods:From March 2014 to December 2021, 15 endemic villages in drinking water-borne endemic fluorosis areas of Dali, Dingbian, Jingbian, Jingyang and Liquan counties in Shaanxi Province were selected as monitoring villages to investigate the operation of water improvement projects. Water samples were collected, and the water fluoride level was detected according to the "Standard Examination Methods for Drinking Water - Nonmetal Parameters" (GB/T 5750.5-2006). "Diagnosis of Dental Fluorosis" (WS/T 208-2011) was done to detect dental fluorosis in all children aged 8 - 12 who were born and lived in the monitoring village. Using "Diagnostic Standard for Endemic Skeletal Fluorosis" (WS/T 192-2008) and "Determination of Fluoride in Urine - Ion Selective Electrode Method" (WS/T 89-2015), X-ray examination and urine fluoride level test were performed on adults over 25 years old who had lived in the monitoring village for more than 5 years, respectively.Results:From 2014 to 2021, a total of 122 water improvement projects were investigated, all of which were in normal operation. The qualified rate of water fluoride increased from 81.25% (13/16) in 2014 to 100.00% (11/11) in 2021. A total of 5 595 children aged 8 - 12 were examined, 1 790 children with dental fluorosis were detected, with a detection rate of 31.99%. The detection rate of dental fluorosis in children decreased from 52.05% (304/584) in 2014 to 9.68% (93/961) in 2021, showing an overall downward trend (χ 2trend = 533.76, P < 0.001). In 2014, 791 adults were examined, and 256 patients with skeletal fluorosis were detected, the detection rate was 32.36%. In 2019, 770 adults were examined, and 88 patients with skeletal fluorosis were detected, with a detection rate of 11.43%. The detection rate of skeletal fluorosis in adults in 2019 was lower than that in 2014, and the difference was statistically significant (χ 2 = 99.54, P < 0.001). In 2014, 754 adult urine samples were collected, and the geometric mean of urine fluoride was 2.571 mg/L. In 2019, 770 adult urine samples were collected, and the geometric mean of urine fluoride was 1.292 mg/L. The geometric mean of urine fluoride in adults in 2019 was lower than that in 2014, and the difference was statistically significant ( Z = - 12.74, P < 0.001). Conclusions:From 2014 to 2021, the water improvement projects in drinking water-borne endemic fluorosis areas in Shaanxi Province are running normally, and the qualified rate of water fluoride has increased. The incidence of dental fluorosis in children and skeletal fluorosis in adults has decreased. In the later stage, it is necessary to continuously strengthen the monitoring and management of water improvement projects to prevent the rebound of water fluoride from causing residents' illness.

Objective:To evaluate the prevention and control effect of coal-burning-borne endemic fluorosis in Ankang City of Shaanxi Province, so as to provide a scientific basis for formulating precise prevention and control strategies in the future.Methods:From 2019 to 2023, according to the requirements of the "Monitoring Program of Shaanxi Province for Coal-burning-borne Endemic Fluorosis (2019 Edition)", full coverage monitoring was carried out in all affected villages in seven affected counties under the jurisdiction of Ankang City. Using the simple random sampling method, 30 households in each affected village were selected to investigate the use of improved stoves and the formation of health-related behaviors. All children aged from 8 to 12 in the village were examined for the prevalence of dental fluorosis. At the same time, 6 monitoring villages were selected in 2019, and 8 monitoring villages were selected in 2023 to collect real-time urine samples from children aged 8 - 12 for determination of urinary fluoride level. The evaluation for control and elimination of disease areas was carried out in accordance with the "Evaluation Approach for Control and Elimination of Priority Endemic Diseases (2019 Edition)".Results:From 2019 to 2023, a total of 203 880 households were monitored, the rate of qualified improved stoves and the correct use rate of qualified improved stoves were more than 95.00%. The utilization rate of improved stoves decreased from 16.34% (6 584/40 290) in 2019 to 8.89% (3 706/41 700) in 2023, showing a decreasing trend year by year (χ 2trend = 3 400.37, P < 0.001). The utilization rate of clean energy increased from 82.52% (33 247/40 290) in 2019 to 94.36% (39 350/41 700) in 2023, showing an upward trend year by year (χ 2trend = 7 506.09, P < 0.001). The correct drying rate of corn and pepper for human consumption were 100.00%. A total of 455 327 children aged 8 - 12 were examined, and 2 301 cases of dental fluorosis were diagnosed, with a detection rate of 0.51%. Children with dental fluorosis were mainly extremely mild and mild, accounting for 94.87% (2 183/2 301). The dental fluorosis index was 0.012, indicating no trend of fluorosis prevalence. The detection rate of dental fluorosis in children decreased from 0.81% (765/94 537) in 2019 to 0.24% (204/86 066) in 2023, showing a declining trend year by year (χ 2trend = 375.45, P < 0.001). The geometric mean urinary fluoride levels of children aged 8 to 12 in 2019 and 2023 were 0.48 and 0.42 mg/L, respectively, with statistically significant differences between groups ( Z = - 3.05, P = 0.002). As of 2023, 1 390 affected villages had met the elimination criteria. Conclusions:The prevention and control of coal-burning-borne endemic fluorosis in Ankang City has achieved remarkable results, with all seven affected counties reaching the elimination standard. In the future, we should strengthen the management of high fluoride coal mines, continue to promote the use of clean energy, strengthen health promotion and disease monitoring, and continuously consolidate and improve the results of prevention and control.

Objective:To study the epidemiological characteristics of mortality and cause of death composition in patients with coal-burning-borne endemic arsenism in Ankang City, Shaanxi Province.Methods:Mortality data of patients with coal-burning-borne endemic arsenism in Ankang City from 2018 to 2023 were collected from the Shaanxi Provincial Endemic Disease Prevention and Control Information Management Platform and the National Death Cause Information Registration System. Crude and standardized mortality rates, years of life lost (YLL) due to premature death were calculated, and the population and regional distribution characteristics of death cases were analyzed. Causes of death were classified and analyzed according to the International Classification of Diseases (ICD-10) category codes.Results:From 2018 to 2023, a total of 610 patients with coal-burning-borne endemic arsenism died in Ankang City, Shaanxi Province. The average annual crude mortality rate was 5.20/100 000. The average age of death for patients was 77.78 years old, and the mortality rate showed an upward trend with age (χ 2tend = 1 163.82, P < 0.001), with a significant increase in patients over 60 years old. The male to female ratio was 3.18∶1.00 (464/146). Among the seven diseased districts and counties, Langao County had the highest mortality rate. The YLL was 6 241.68 person-years. The top four causes of death among these cases circulatory system diseases, respiratory system diseases, malignant tumors, and injuries differed from those of the entire population in Ankang City, with respiratory system diseases being more prominently ranked. Conclusions:The death cases of coal-burning-borne endemic arsenism in Ankang City are mainly elderly males, and are more common in Langao County. There are various causes of death, coexisting with circulatory system diseases, respiratory system diseases, malignant tumors, and injuries.

Objective:To learn about the changes of the condition of coal-burning-borne endemic arsenism, the use of improved stoves and the formation of health-related behaviors in Shaanxi Province, and evaluate the effect of prevention and control measures.Methods:From 2015 to 2020, according to the "Implementation Plan for Monitoring Coal-burning-borne Endemic Arsenism in Shaanxi Province", regular field surveys were carried out in 4 natural villages, 2 counties in Ankang City and Hanzhong City, Shaanxi Province, to learn about the basic prevention and control situation in the monitoring village. Using the simple random sampling method, 10 families in each village were selected to investigate the use of stoves and the formation of health-related behaviors, and 5 of these families were selected to collect coal samples for arsenic content determination in accordance with the "Determination of Arsenic in Coal" (GB/T 3058-2008). According to the "Diagnosis of Endemic Arsenicosis" (WS/T 211-2015), the condition of the people exposed to high arsenic coal in the monitoring village was investigated. Urine samples of 30 adult patients (half males and half females) with arsenic poisoning were collected, the content of arsenic in urine was determined by the "Urine-Determination of Arsenic-Silver Diethyldithiocarbamate-Triethanolamine-Spectrophotometric Method" (WS/T 28-1996).Results:A total of 240 households were monitored in the past 6 years, and the quality conformance and correct utilization rates of improved stoves in the households monitored in the disease areas remained at 100.00% in 2018 - 2020. The utilization rate of clean energy increased from 75.00% (30/40) in 2015 to 100.00% (40/40) in 2018 - 2020 (χ 2trend = 25.5, P < 0.001). The 73.75% (177/240) of households using a variety of clean energy. From 2018 to 2020, the correct drying, storage and pre-processing washing rates of corn and pepper continued to reach 100.00% (40/40). The arsenic content of coal ( n = 120) in the disease areas was (118.09 ± 57.91) mg/kg, ranging from 16.70 to 280.94 mg/kg. The detection rate of arsenic poisoning decreased from 6.34% (231/3 646) in 2015 to 2.90% (109/3 754) in 2020 (χ 2trend = 121.8, P < 0.001), and no skin cancer or Bowen's disease was detected. The geometric mean of arsenic content in urine ( n = 720) was 0.038 1 mg/L, ranging from 0.000 5 to 0.312 9 mg/L. Conclusions:The condition of coal-burning-borne endemic arsenism areas in Shaanxi Province has reached the national elimination standard. The quality and correct utilization rate of improved stoves and the rate of using clean energy have increased. The healthy-related behaviors the people in the endemic areas have been basically formed. The prevention and control work has achieved good results.

Objective To investigate the correlation between the prevalence of dental fluorosis in children and the intake of dietary nutrients. Methods A total of 81 children aged 8-12 (34 males and 47 females) with fluorosis were randomly selected in the districts of Daxu, Fuping, and Fuyang in Shaanxi Province where the drinking water had been changed for more than 5 years. The diagnosis of dental fluorosis was carried out using Dean's method. According to the 1:1 case-control study method, 81 children aged 8-12 (34 males and 47 females) without dental fluorosis were selected as a control group. A ^“double meal method^“ was employed for dietary investigation for 3 consecutive days. The differences in dietary nutrient intake between the two groups of children were analyzed and compared. Results There was no significant difference between the two groups (P>0.05). Compared with the control group, the difference in the dietary intake of vitamin C, vitamin E, calcium, magnesium, iron, zinc, copper, phosphorus, and selenium in the fluorosis group was not statistically significant (P>0.05). The logistic regression analysis of the prevalence of dental fluorosis in children showed that the dietary nutrient magnesium was associated with the onset of dental fluorosis. Conclusion Within a certain range, dietary magnesium is a protective factor for children with dental fluorosis. It is suggested that school-age children in areas with excessive water fluoride should be supplemented with sufficient magnesium in their diets.

Objective:To investigate the arsenic content in internal and external environment of the people in drinking-water-borne endemic arsenic poisoning areas in Shaanxi Province, the status quo of the disease and the management and services of the existing patients, so as to provide a theoretical basis for evaluating the effect of prevention and control measures on drinking-water-borne endemic arsenic poisoning.Methods:From 2019 to 2020, in accordance with the requirements of the "Notice of Shaanxi Provincial Health Commission on Issuance of Monitoring Plans for Key Endemic Diseases such as Kashin-Beck Disease" and "Monitoring Plans for Drinking Water Arsenic Poisoning in Shaanxi Province", investigation was carried out in all villages of drinking-water-borne endemic arsenic poisoning in Mianxian County of Hanzhong City, Shanyang County and Zhen'an County of Shangluo City to understand the operation of water improvement project. One terminal water sample was collected to determine the content of arsenic in water, and permanent population of the whole village who are and/or had been exposed to excessive arsenic water in the past were examined for arsenic poisoning and the disease condition was determined according to the standard of "Diagnosis of Endemic Arsenicosis" (WS/T 211-2015). Five villages were randomly selected, and 50 people were selected from each village. Real-time urine sample was collected to determine the content of urinary arsenic. At the same time, management and services of the existing arsenic poisoning patients was investigated.Results:A total of 13 villages were investigated, all of which had been improved in water quality, and all 13 water improvement projects were operating normally, with arsenic content < 0.01 mg/L. A total of 12 577 people were examined, and 417 cases of arsenic poisoning were detected, with a detection rate of 3.32%. No new arsenic poisoning case and arsenic-related skin cancer case had been detected. A total of 260 urine samples were detected, and the geometric mean value of urinary arsenic (< 0.001 mg/L) was lower than the safety guideline value of human urinary arsenic (0.032 mg/L). The existing arsenic poisoning patients (417 cases) were included in health management and contracted services.Conclusions:Shaanxi Province has reached the elimination standard of drinking-water-borne endemic arsenic poisoning. In the future, more attention should be paid to the management of water improvement project, as well as to strengthen health promotion and management services for existing patients to consolidate the effects of prevention and control.

Objective:To investigate the relationship between different fluorine concentrations in drinking water and dental fluorosis and caries of children.Methods:In 2014-2019, 5 cities and 6 counties (districts) were selected, which were Dali and Heyang counties of Weinan City, Liquan County of Xianyang City, Fugu County of Yulin City, Chencang District of Baoji City, and Yanliang District of Xi'an City, villages of different water fluorine contents were selected, 3 tap water samples were collected from each village to detect the water fluoride content. The prevalence of dental fluorosis and caries in children aged 8 to 12 years old in villages was investigated, and children's urinary fluorine level was determined.Results:Totally 48 water samples and 868 urine samples were tested, and the water fluorine content was from 0.23 to 3.70 mg/L, and the urinary fluorine mean was 1.47 mg/L; 1 021 children aged 8-12 years old were examined, 372 were diagnosed with dental fluorosis, the detection rate was 36.43%; 198 with caries, the detection rate was 19.39%. The detection rate of caries in children decreased and then increased with the increase of water fluorine ( F=14.470, P < 0.05), and the detection rate of caries was the lowest when the water fluorine was 1.2-< 2.0 mg/L. The detection rate of dental fluorosis in children increased with the increase of water fluorine ( F=52.215, P < 0.05), when the water fluoride was 1.0-< 1.2 mg/L, the detection rate of children's dental fluorosis was 31.90% (37/116), which was basically within the national control line (30%). Conclusion:The content of water fluoride in 1.0-< 1.2 mg/L, can not only reduce the detection rate of caries, but also control the prevalence of dental fluorosis.

Objective To investigate the urinary arsenic levels of exposed population in various forms of and total arsenic (TAs) content as well as their relationship with arsenic poisoning in southern Shaanxi arsenic poisoning area.Methods According to the historical data of the investigation on arsenic poisoning,11 disease villages were chosen as survey sites in Ziyang and Pingli counties,Ankang city;three neighbor villages were chosen as control sites in Baihe.Baihe was a non-endemic arsenic poisoning area county,which had the same natural environment and living habits.In the survey sites,people over the age of 40 were selected for epidemiological investigation in both heating and non-heating seasons,and 40 urine samples were collected at each severity levels of the disease and in different seasons.Meantime,20 urine samples of the same age group were collected in the control sites in each season.Hydride generation-atomic fluorescence spectrometry (HG-AFS) was used to determine TAs,liquid chromatography-hydride generation-atomic fluorescence spectrometry (LC-HG-AFS) was used to determine the amount of inorganic trivalent arsenic (As3+),dimethylarsine (DMA),monomethylarsine (MMA) and inorganic pentavalent arsenic (AS5+),and the various forms and TAs were compared between different survey sites,severity levels,ages,sexes,and seasons.Results The medians of TAs,As3+,DMA,primary methylation index (PMI),and secondary methylation index (SMI) in diseased area (35.3,2.2,24.5 μg/L;0.84,0.90) were significantly higher than those of the control group (16.0,0.6,10.3 μg/L;0.78,0.81;Z =-9.069,-7.314,-8.913,-2.183,-3.853,P ＜ 0.01 or ＜ 0.05),and the medians of TAs,As3+,DMA,and SMI (31.6,2.0,23.1 μg/L;0.91) of the normal population in the diseased area were significantly higher than those of the control group (16.0,0.6,10.3 μg/L;0.81;Z =-7.164,-6.136,-7.023,-2.916,all P ＜ 0.01).Illness had positive correlations with TAs,DMA,and ages (r =0.370,0.367,0.594,all P ＜ 0.01).Men arsenic poisoning detection rate,TAs,As3+,and DMA (59.9％,37.4,2.5,25.2 μg/L) were significantly higher than those of women (22.4％,30.0,1.6,20.9 μg/L;x2 =54.878,P ＜ 0.01;Z =-3.332,-4.449,-2.681,all P ＜ 0.01).The medians of As3+,MMA,As5+,PMI,and SMI in the heating season (1.5,2.1,1.4 μg/L;0.87,0.92) were significantly different from those in the non-heating season (2.6,3.3,3.0 μg/L;0.82,0.88;Z =-6.870,-5.512,-8.542,-2.262,-4.544,P ＜ 0.01 or ＜ 0.05).Conclusions The TAs,As3+,and DMA of urine samples are related to local arsenic background,so they have some reference value for determination of diseased areas.Men are more susceptible to arsenic poisoning than women.

Objective To investigate the relationship between levels of arsenic and selenium in hair and urine of patients with arsenic poisoning caused by coal-burning.Methods Based on the Standard of Diagnosis for Endemic Arsenism (WS/T 211-2001),about fifty arsenism or suspicious patients over 40 years old were separately selected from Haoping Town and Shuang'an Town of Ziyang County,and the high-arsenic stone coal of Haoping Town was consumed in these two towns,all patients were divided into suspicious,light,moderate,and severe groups.Five coal samples were collected from homes of patients with arsenic poisoning,which were crushed to pieces and sufficiently mixed,0.5 kg of the crushed coal was collected by quartering method to determine arsenic and selenium content;at the same time,5 water samples were collected in homes of patients with arsenic poisoning to determine arsenic and selenium content;in each investigation site,5 ploughs were selected according to the five directions as east,west,south,north and centre,to collect 15-30 cm soil of plough layer,after blending with four points method of shrinkage,1.0 kg was collected to determine arsenic and selenium content in the soil;the urine of all patients instantly and 0.5 g hair sample within 20 mm from the scalp on occiput were collected to determine arsenic and selenium content.Dual channel atomic fluorescence spectrophotometer was used to measure the arsenic and selenium content in the coal,water,soil,urine and hair samples.The contents of arsenic and selenium in coal,water and soil were expressed as （x） ± s;the contents of arsenic and selenium in urine and hair were expressed as medium (M) and quartile range (QR).Results The patients with arseniasis in moderate and severe groups from Shuang'an Town accounted for 9.8％ (5/51) of the total number of patients;the patients in moderate and severe groups from Haoping Town accounted for 39.2％ (20/51).Compared between the two towns of the proportion of arsenic poisoning clinical index,the difference was statistically significant (x2 =31.224,P ＜ 0.01).Compared between Haoping Town and Shuang'an Town,the arsenic contents of soil [(150.71 ± 127.10),(71.10 ± 22.75) mg/kg],water [(0.004 1 ± 0.000 2),(0.006 3 ± 0.000 4) mg/L],urine [0.025 2 (0.023 2),0.026 7 (0.025 6) mg/L] and hair [2.54 (3.52),2.81 (5.98) mg/kg] were not significantly different (Z =-0.913,-1.776,-0.079,-0.544,all P ＞ 0.05).The selenium contents of soil [(5.93 ± 5.76) mg/kg],water [(0.036 9 ± 0.001 8) mg/L],urine [0.056 3 (0.152 2) mg/L] and hair [3.65 (5.43) mg/kg] in Shuang'an Town were higher than those of Haoping Town [(2.41 ± 1.03) mg/kg,(0.006 1 ± 0.000 6) mg/L,0.015 6 (0.013 4) mg/L and 1.52 (2.05) mg/kg],the differences were statistically significant (Z =-2.619,-2.611,-4.765,-2.485,all P ＜ 0.01).There was a positive correlation between hair arsenic and arsenic in clinical grading (r =0.874,P ＜ 0.01);there was a negative correlation between hair selenium and arsenic in clinical grading (r =-0.400,P ＜ 0.01).Conclusions High selenium environment affects the severity of patients with arsenic poisoning,indicating that selenium may promote arsenic metabolism and reduce arsenic accumulation in vivo.Selenium may have an antagonist effect on arsenic.