0.05). Conclusion High fluoride may cause children intelligence decrease.

Objective To master the running conditions of water project and the defluoridation results in monitoring sites of drink-water type fluorosis in Shaanxi Province,to provide a scientific basis of preventing and controlling endemic fluoroisis. Methods Every April and September 1998—2005 children aged 8～12 at school from the two monitoring sites of Wupo and Bayi village received the dental fluorosis examination by using the Deans method.The urine samples of 50 children from 5 age groups who were selected randomly and were grouped in 5 with 10 children each were collected,measured in accordance with WS/T 89—1996 Determination of Fluoride in Urinlon Selective Electrode Method,evaluated by Manual of Endemic Fluorosis Control(1991). At least 5 water samples were collected randomly from five directions(east,west,north,south,center).The fluoride contents in urine and drinking water were determined with FSIE,in accordance with GB/T 5750--2006 Standard Examination Methods for Drinking Water,evaluated by GB 5749—2006 Standards for Drinking Water Quality.Results After changing water,morbidity rate of children dental fluorosis fell from 66.67%in 1998 to 31.79%in 2005 and the dental fluorosis index also fell form 1.49 to 0.65 of Wupo village,morbidity rate of children dental fluorosis fell from 33.15%in 1998 to 13.10%in 2005 and the dental fluorosis index also fell from 0.50 to 0.24 of Bayi village.The fluoride contents in urine of children and the fluoride contents in drinking water were maintained stability.Conclusion After water improvement,the fluorosis has been effectively controlled in a certain degree in the investigated area.

Objective To understand the situation of indoor air fluoride and arsenic pollution caused by coal-burning and the impact of the pollution on children health in the rural area,southern Shaanxi Province.Method 77 fluoride samples and 186 arsenic samples were collected in 65 investigated villages of 5 counties in southern Shaanxi Province.13 120 children aged 8-12 years were selected for dental fluorosis examination,13 386 children aged 6-18 years for arsenism examination.Results Both of the average content of fluoride and arsenic in the indoor air exceeded the national standard limit.Fluorine content was 0.001-0.541 mg/m3 with an average of 0.038 4 mg/m3,arsenic content was 0.00-63.83 ?g/m3 with an average of 4.76 ?g/m3.The prevalence rates of dental fluorosis and arsenism were 45.50% and 1.86% respectively.Conclusion The indoor air fluoride and arsenic pollution caused by coal-burning in the investigated rural area is serious and the pollution has caused the prevalence of endemic fluorosis and endemic arsenism among the local children.

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.

Objective To understand the schedule and effectiveness of water-improving defluoridation projects comprehensively in control of fluorosis in drinking-water-borne endemic fluorosis areas in Shaanxi Province,and to provide a scientific basis for making strategies in prevention and control the disease for the next step.Methods The progress of drinking-water-borne endemic fluorosis water-improving defluoridation projects and operation condition were investigated in Shaanxi (fluoride content of drinking water was greater than 1.2 mg/L in the endemic areas) in 2014,and children aged 8 to 12 in 32 epidemic villages of six counties including Jingbian,Dingbian,Dali,Jingyang,Qian and Liquan were selected to survey dental fluorosis.Results In Shaanxi Province,the number of villages with water fluorine content of more than 1.2 mg/L was 5 005 and water improvement rate was 83.42％ (4 175/5 005),water-improving projects operated normally rate was 85.05％ (3 551/4 175),and scraped was 37,accounted for 0.89％ (37/4 175).There were 830 epidemic villages without water-improving projects in Shaanxi Province,and high fluoride exposed population was 579 400,mainly distributed in Yulin,Xianyang,Weinan and Yan'an cities.A total of 1 849 children aged 8 to 12 in the 6 counties were examined,the detection rate of dental fluorosis was 56.57％ (1 046/1 849),the index of dental fluorosis was 1.11.Conclusion In drinking-water-borne fluorosis epidemic areas of Shaanxi,the improved-water rate is generally high,and the normal operation of waterimproving projects is overall good,but the measures for water-improving defluoridation must be reinforced and improved.

Objective To investigate the current situation of coal-burning-borne endemic arsenism in the disease affected areas,the usage of anti-arsenism stove and the formation of related behavior;,to evaluate the control effect,so as to provide a basis for development of control strategies.Methods Surveillances were carried out according to the provisions and requirements of The Surveillance Project for Shaanxi Institute Coal-Burning-Borne Endemic Arsenicosis (Trial.).Four villages in two counties of Ankang city and Hanzhong city in Shaanxi Province were monitored in 2010-2014.Using simple random sampling method,10 families in each village were randomly selected to survey the situation of the stove used and related behavior changes.Five households in each village were randomly selected; arsenic level in coal was determined; high arsenic exposed population was investigated according to Endemic Arsenism Diagnostic Criteria (WS/T 211-2001).Urine samples of 30 patients with arsenism were randomly selected to determine the arsenic content.Results The proper utilization rate and the qualified households of improved stoves and iron stoves were all low; the correct drying rate and the correct storage rate of peppers and corns were higher than 95％.The washing rate of corns and peppers before eating were all 100％.A total of 100 copies of coal samples were tested and the arsenism content was between 12.295-455.827 mg/kg,and the geometric mean value of the arsenism content was (91.819 ± 80.989)mg/kg.Seventeen thousand eight hundred and fifty-five individuals were investigated and 1 232 cases of arsenism were diagnosed in the 4 villages; the prevalence rate was 6.90％ (1 232/17 855); urinary arsenism content was between not detected-0.287 mg/L; and the geometric mean value of the arsenic content was 0.033 mg/L.Conclusions The coal-burning-borne endemic arsenism in Shaanxi is in a prevalent state; many anti-arsenism stoves are out of order; and the proper utilization rate is low.To strengthen the disease surveillance,health education and management of anti-arsenism stoves are key measures in control of coal-burning borne endemic arsenism in the future.

Objective To investigate the influence of fluoride and arsenic exposure on children's intelligence and growth development.Methods The illness seriously and lightly affected areas in the coal-burning-borne arsenism and fluorosis areas in the south part of Shaanxi were selected as survey sites from 2011 to 2012,while the illness non-affected areas as controls.Children's IQ was tested,dental fluorosis and growth level of 8-12-year-old students in the school were investigated by random sampling,and the differences of children's IQ and the level of their growth among different groups were analyzed.Urine samples of the children were collected to determine the fluoride and the arsenic content.Results In the illness seriously affected,lightly affected and nonaffected areas,the medians of urinary fluoride of children were 1.96,0.81 and 0.54 mg/L,respectively; and the medians of their urinary arsenic were 0.023,0.019 and 0.018 mg/L,respectively.The average IQ levels were 101.22 + 15.97,104.83 ± 12.78 and 107,92 + 13.62,respectively.In illness seriously affected,lightly affected and non-affected areas,the differences of their height,weight,chest circumference and lung capacity between groups(x2 =36.549,25.859,28.021 and 45.627,all P ＜ 0.01) were significantly different.The height,weight,chest circumference and lung capacity of the children in illness seriously affected(136 cm,31 kg,64 cm,1 432 ml) and lightly affected areas (137 cm,30 kg,65 cm,1 433 ml) were all less than those of the illness non-affected areas (141 cm,34 kg,67 cm,1 660 ml,Z =-5.858,-4.151,-4.196,-4.500,-5.189,-3.240,-6.698 and -4.008,all P ＜ 0.01) ; lung capacity of children in illness seriously affected areas was less than that of the illness lightly affected areas (Z =-2.395,P ＜ 0.05).Their urinary fluoride and arsenic levels were negatively correlated with their IQ(r =-0.560,-0.353,all P ＜ 0.05).Conclusions Fluorine and arsenic exposure is not conducive to children's intellectual development and growth.We propose to strengthen the measure of changing stove furnace in order to provide a healthy growth environment for children.

Objective To investigate the usage of defluoridation stove and the formation of related behavior in the disease affected areas and the current situation of coal-burning-borne endemic fluorosis,to evaluate the control effect,so as to provide a theoretical basis for superior department to adjust the control strategy in time.Methods According to The Implementation Plan for Prevention and Treatment of Coal-burning-borne Endemic Fluorosis in Shaanxi Province,Ziyang and Langao in Ankang City were chosen for epidemiological survey.Using stratified sampling method,according to the degree of disease situation,each county was divided into 3 layers and then 5％ from each layer was extracted to carry out an investigation,respectively.The number of investigated village was at least 1,up to 30.The number in a non-endemic area was 1-3.Questionnaire survey of all residents was carried out to ask of the changes of cooking and heating fuel;the correct usage of the improved stove;the changes of life behavior related to the corn and pepper for human consumption and the development of prevention and treatment of post management.In endemic areas and in non-endemic areas,according to the Determination of Fluoride in Foods (GB/T 5009.18-2003),fluoride levels of corn (or rice) and chili which collected from 10 families were determined.Meanwhile,the criteria for Diagnosis of Dental Fluorosis (WS/T 208-2011) was used to diagnose dental fluorosis and the criteria of Urine-determination of Fluoride-ion Specific Electrode Method (WS/T 89-1996) was used to evaluate urine fluoride;dental fluorosis of every child aged 8-12 was examined and 10 copies of urine samples were randomly collected in each age group.Housewives and students over the age of 16 in endemic areas were quizzed of the knowledge of health and diagnosed serious skeletal fluorosis according to The Diagnostic Criteria of Endemic Fluorosis (WS 192-2008).Results The rates of correct usage of improved furnace and oven were 91.43％ (3 019/3 302) and 95.72％ (3 578/3 738).The autonomous maintenance rate of stoves was 0.61％ (49/7 998).In endemic areas,the correct drying rate and the correct storage rate of corn and pepper were all 100.0％ (300/300);the washing rate of corn and pepper before eating was 98.3％ (7 863/7 998).The fluoride median contents of corn and pepper was 0.800 and 2.863 mg/kg,respectively.In non-endemic areas,The fluoride median contents of corn and pepper was 0.443 and 4.065 mg/kg,respectively.The awareness rates of health knowledge were 81.27％ in housewives and 90.32％ in students.Dental fluorosis detection rate of 8-12 years old children was 12.52％ (87/695);the fluoride content was between 0.04-7.00 mg/L and the geometric mean value of fluoride content was 0.61 mg/L in endemic areas.There was no new case of serious skeletal fluorosis.Conclusions The prevention effect is obvious.Disease surveillance,health education and management of defluoridation stoves are keys to prevent coal-burning-borne endemic fluorosis.

Objective To investigate the characteristics of X-ray signs of water-related and coal-burning borne endemic fluorosis in Shaanxi Province,so as to provide a theoretical basis for revising X-ray diagnostic criteria of skeletal fluorosis in the future.Methods The X-ray data of 2 525 cases of patients with endemic fluorosis from the central subsidies to local public health programs were collected from 2008 to 2011,and the X-ray signs,age,gender distribution,detection rate were analyzed statistically ; skeletal fluorosis was diagnosed on the basis of skeletal diagnostic criteria(WS 192-2008).Results The 2 525 cases observed were taken X-ray film on forearm and shank.In the X-ray signs of patients from fluorosis areas,the detection rates were higher,and these signs were mainly radial crest of increase,marginal sclerosis,surface thickening and forearm interosseous membrane ossification and forearm interosseous membrane calcification which showed bud break ground sign,which accounted for 29.91％(242/809),17.92％(145/809) and 17.69％ (143/809),respectively.Three X-ray signs occurred in the forearm,and the total detection rate based on the forearm signs was 88.12％ (721/809); 682 cases of skeletal fluorosis were detected and the detection rate was 27.01％ (682/2 525),including 401 mild cases accounting for 15.88％ (401/2 525); 236 moderate cases that accounted for 9.35％ (236/2 525); 45 severe cases accounted for 1.78％(45/2 525).With age,the prevalence increased gradually.After the age of 55 reached the peak,and the difference was significant statistically between different ages (x2 =228.58,P ＜ 0.05).The total prevalence was not significantly different between male group and female group (x2 =0.74,P ＞ 0.05).Conclusions With age,the prevalence of skeletal fluorosis is increased,and the skeletal fluorosis is not different between different sexes.The X-ray sign results have showed that the prevalence based on forearm signs is high and specific.We suggest to diagnose skeletal fluorosis by the X-ray signs of the forearm in the diagnostic standard revision,so as to reduce financial input,workload and radiation level to the patient.