Objective To establish and evaluate a method for determination of total arsenic in urine by test-tube rapid digestion hydride generation atomic fluorescence spectrometry.Methods After digestion of urine samples using graduated test-tube and graphite digestion apparatus,arsenic content in urine was determined with atomic fluorescence spectrometer.Then the test results were evaluated by using quality control measures,such as precision and accuracy experiments,and the results between different laboratories were reviewed and compared.Results The urinary arsenic was in a linear range of 0-0.300 mg/L,correlation coefficient (r) ＞ 0.999 3,detection limit was 0.000 21 mg/L,relative standard deviation (RSD) ≤4.62％ and the recoveries of standard addition were 93.9％-104.3％.The value of standard reference material measured was within the allowable range.The blind sample of the national urinary arsenic was qualified.Conclusions This method is suitable for large scale determination of urinary arsenic for its micro sample amount needed,less interference and strong practicability.The error results are in a controlled range.

Objective To find out the distribution of drinking-tea-borne fluorosis in the six ethnics in Qinghai Province, and to provide basic data for prevention and control of the disease. Methods In 2010, according to the requirement of “The National Surveillance Program of Drinking-Tea-borne Fluorosis”, six ethnics accounted for 99.59% of total population in Qinghai Province were investigated in 28 counties having brick-tea drinking habit. Three townships and a town in each county, two administrative villages(residents’ committee) in each township and town were chosen and 50 adults in each administrative village and residents ’ committee were selected to check skeletal fluorosis, dental fluorosis, urine fluoride and daily drinking amount of tea water. Five to six samples of drinking tea water were determined. Dental fluorosis was examined by Deans method; the fluoride content of brick-tea and urine were determined by fluoride ion selective electrode; the skeletal fluorosis was diagnosed based on “Endemic Osteofluorosis Clinical Indexing Diagnosis Standard”( WS 192-2008 ) . Results A total of 10 335 adults were surveyed, the number of Tibetan, Han, Hui, Mongolian, Tu and Salar ethnics were 4 972, 3 063, 1 196, 634, 235 and 235, respectively. The daily drinking amounts of tea water in Mongolian, Tibetan, Hui, Tu, Han and Salar ethnics were 2.53, 2.19, 1.74, 1.63, 1.22 and 1.07 L, respectively. Daily fluoride intakes in Tibetan, Mongolian, Tu, Hui, Han and Salar ethnics were 3.99, 2.78,2.27, 2.16, 1.78 and 1.28 mg, respectively. The medians of urinary fluoride concentration of the Tibetan, Tu, Hui, Han, Mongolian and Salar ethnics were 1.46, 1.19, 1.12, 0.98, 0.93 and 0.81 mg/L, respectively. The prevalence rates of dental fluorosis of the Hui, Han, Tibetan, Tu, Mongolian and Salar ethnics were 34.53%(413/1 196), 27.07%(829/3 063), 21.60%(1 074/4 972), 20.00%(47/235), 17.98%(114/634) and 6.38%(15/235), respectively. The incidence rates of clinical skeletal fluorosis of the Tibetan, Mongolian, Han, Hui, Tu and Salar ethnics were 13.42%(667/4 972), 11.04%(70/634), 9.31%(285/3 063), 7.61%(91/1 196), 5.53%(13/235) and 4.26%(10/235), respectively. Conclusions The distribution and prevalent status of drinking-tea-borne fluorosis in the six ethnics of Qinghai Province are different. Tibetan and Mongolian ethnics are the key population concerning the prevention and control of the disease.

Objective:To understand the situation of drinking water-borne endemic fluorosis (short for drinking water fluorosis) in Huangzhong, Ping'an and Ledu districts of Qinghai Province and operation status of water improvement projects, and to evaluate the effect of control measures.Methods:In historical drinking water fluorosis villages of Huangzhong, Ping'an and Ledu districts of Qinghai Province in 2018, the status of water improvement, the operation of water improvement projects and the content of water fluoride were investigated; the dental fluorosis of 8-12 years old children in all investigated villages was checked; 3 villages from 3 districts were selected, X-ray examination for skeletal fluorosis and urinary fluoride detection of adults over 25 years old of age were performed.Results:Eight-two historical drinking water fluorosis villages in 3 districts were investigated and all the villages had water improvement projects, in addition, the water improvement projects were operating normally, and the water fluoride content ranged from 0.10 to 0.37 mg/L, which were in line with the drinking water fluoride content standard (< 1.2 mg/L). Totally 2 503 children aged 8-12 years old were examined, the detection rate of dental fluorosis was 6.03% (151/2 503), the index of dental fluorosis was 0.13, the epidemic intensity was negative; the detection rates of dental fluorosis in 3 districts were 6.24% (129/2 068), 4.05% (7/173), 5.73% (15/262), respectively, reaching the control standard (< 30%), and the detection rate of dental fluorosis in 81 villages was less than 30%; 198 adults over 25 years old were examined, the detection rate of skeletal fluorosis was 5.05% (10/198), the geometric mean of urinary fluoride was 0.81 mg/L, and skeletal fluorosis cases were mainly in the age group over 40 years old, all of them were mild cases.Conclusions:The fluoride content in drinking water and the detection rate of children's dental fluorosis are all up to the control standard, and the condition of skeletal fluorosis is significantly reduced after the implementation of water improvement measures in Huangzhong, Ping'an and Ledu districts. It can be seen that the prevention and control of drinking water fluorosis in Huangzhong, Ping'an and Ledu districts have achieved good results, but later management and condition monitoring of water improvement projects should be strengthened to prevent the disease from rebounding.

Objective:To verify the revised method of cerium sulfate catalytic spectrophotometry for iodide index of "Standard Examination Methods for Drinking Water-Nonmetal Parameters" (GB/T 5750.5-2006).Methods:From July to September 2019, the Laboratory of Department for Endemic Disease Prevention and Control of Qinghai Institute for Disease Prevention and Control verified the revised method (determination of iodide in drinking water by cerium sulfate catalytic spectrophotometry) of cerium sulfate catalytic spectrophotometry (hereinafter referred to as original method) in "Standard Examination Methods for Drinking Water-Nonmetal Parameters" (GB/T 5750.5-2006). The revised method was verified according to the requirements of "Standard Examination Methods for Drinking Water-Water Analysis Quality Control" (GB/T 5750.3-2006), including standard curve, detection limit, precision, accuracy and actual sample determination.Results:The linear range of the revised method was 0 - 20.0 μg/L, the correlation coefficient was - 0.999 4 - 0.999 8, and the detection limit was 0.231 μg/L. The relative standard deviation ( RSD) of low, medium and high iodine water samples of 6 times detection ranged from 1.4% to 9.6%, and the recoveries of low and medium water samples ranged from 89.0% to 108.0%. The detection results of national first-class reference materials for iodine composition analysis in water were within the range of standard value ± uncertainty. There was no significant difference in the test of results of 12 tap water samples between the revised method and the original standard method ( t = - 0.075, P > 0.05). Conclusion:The revised method has a good linear relationship of standard curve, high precision and accuracy, and good reproducibility, is simple and easy to operate, and is suitable for promotion and application.

Objective To observe the illness change trend of drinking water type endemic arsenic poisoning in Qinghai Province, comprehensively evaluate the effect of prevention and control measures, in order to provide a scientific basis for timely adjustment of the prevention and control measures. Methods From 2010 to 2013, according to the Drinking Water Type Endemic Arsenic Poisoning Monitoring Programs, 3 villages in 2 counties within Qinghai Province were randomly selected as monitoring sites. The arsenic content in drinking water of residents was measured, water improvement projects in all monitoring villages were investigated; at the same time an investigation of arsenic disease in resident population was conducted, and urinary arsenic content was monitored. Arsenic in drinking water and urine was determined by hydride generation atomic fluorescence spectrometry, and arsenic poisoning was diagnosed using Endemic Arsenic Poisoning Diagnostic Criteria (WS/T 211-2001). Results Of the three water improvement projects, two were water arsenic exceeded the standard, and one was intermittently operated. From 2010 to 2013, the arsenic poisoning detec tion rate in Baoning Village was 27.30% (193/707), 31.90%(245/768), 29.35%(221/753) and 28.22%(219/776); in Kecai Village was 32.62%(107/328), 34.83%(124/356), 31.26%(131/419) and 29.35%(118/402);and in Manimotai Village was 56.58%(43/76), 52.81%(47/89), 45.10%(46/102) and 34.69% (34/98), there was no significant difference statistically of the arsenic poisoning detection rates in the three monitored villages in the 4 years (χ2 =3.09, 0.04, 0.92, all P>0.05). From 2010 to 2013, women arsenic poisoning detection rate was 36.45%(203/557), 40.59%(246/606), 36.12%(225/623) and 34.77%(218/627), respectively;men was 25.27%(140/554), 28.01%(170/607), 26.57%(173/651) and 23.57%(153/649), respectively;women arsenic poisoning detection rates were higher than those of men (χ2 = 16.25, 21.32, 13.49, 19.38, all P < 0.05). Arsenic poisoning detection rate of people younger than 60 years old had a tendency to increase with age. In 2012 and 2013, 105 and 93 urine samples were tested, respectively; urinary arsenic geometric mean was 0.113 and 0.149 mg/L. Conclusions Water improvement projects and water quality are not optimistic, and prevalence of arsenic poisoning is still at a higher level. A sound long-term monitoring program should be established as soon as possible, the management and maintenance of water improvement projects should be strengthened, and the monitoring and prevention work should not be neglected.

Objective To understand the current environmental selenium and T-2 toxin levels in the critically ill areas of Kaschin-Beck disease in Qinghai Province.Methods In three historical villages with serious diseases of Kaschin-Beck disease,Xia,Xiemalang and Yaoshidao were selected;at the same time,three villages from non-diseased areas were selected as control villages including Damitan,Gongba and Deang in 2018.Six villages were used as survey sites.Collected hair samples of children aged 6-12 years old,to measure the hair selenium content in Xinghai and Guide survey sites [children's selenium content reference value was (0.60 ± 0.03)mg/kg].Ten samples of self-produced grain were collected from each survey site,selenium content [wheat selenium content reference value was (0.053 ± 0.007) mg/kg] and T-2 toxin content in grain was detected in the six survey sites.Ten soil samples were collected from each survey sites.Soil selenium content was detected in the six survey sites [soil selenium content reference value was (0.24 ± 0.03) mg/kg].Results The selenium contents of children's hair in the diseased and non-diseased areas of Xinghai County,Guide County were (0.252 ± 0.071),(0.296 ± 0.087);(0.225 ± 0.032),(0.238 ± 0.040) mg/kg,respectively.The selenium contents of wheat in the diseased and nondiseased areas of the three counties were 0.000 19,0.003 66;0.000 15,0.004 16;0.016 78,0.016 94 mg/kg.The soil selenium contents in the diseased and non-diseased areas of the three counties were (0.095 ± 0.015),(0.114 ± 0.014);(0.082 ± 0.013),(0.083 ± 0.018);(0.080 ± 0.005),(0.060 ± 0.013) mg/kg.The T-2 toxin contents of wheat in the diseased and non-diseased areas of the three counties were (3.173 ± 0.762),(3.100 ± 0.473);(2.506 ± 0.430),(3.186 ± 0.451);(2.416 ± 0.619),(2.879 ± 0.456) μg/kg.Conclusions The content of hair selenium of children is close to the normal reference value in the area of Kaschin-Beck disease in Qinghai Province.The contents of soil selenium and the main grain selenium of the residents are low in the diseased village.A certain amount of T-2 toxin is detected in the main grain of residential households.

Objective To explore the prevalence state of drinking brick-tea type fluorosis in children in Guoluo Prefecture,Qinghai Province.Methods According to the historical prevalence of drinking tea-type fluorosis in Guoluo Prefecture,in 2017,in 5 counties of Guoluo Prefecture,according to the pastoral area,agricultural area,semi-agricultural and semi-pastoral areas,each township (town) was selected,in each township (town) drawed a natural village in a ward as a survey point.At each survey site,drinking water samples of local residents were collected,and 10 households were selected,tea samples were collected,and dental fluorosis was investigated for children aged 8-12 years old.The mean of fluoride was determined by fluoride ion selective electrode method (GB/T 5750.5-2006,GB 19965-2005),and the dental fluorosis was diagnosed based on "Diagnosis of Dental Fluorosis" (WS/T 208-2011).Results The mean of fluoride in 85 water samples was 0.34 mg/L (0.20-0.77 mg/L),the mean of fluoride in 161 brick-tea samples was 579 mg/kg (110-1 278 mg/kg).The mean of daily fluoride intake of each person was 6.78 mg,among them,73.29％ (118/161) drank brick-tea,the detection rate of dental fluorosis of 2 083 children was 22.85％ (476/2 083),and the index of dental fluorosis was 0.42,the prevalence was weak.Conclusion The prevalence of drinking brick-tea type fluorosis of children in Guoluo Prefecture is less serious.

Objective:To investigate the contents of soil metal elements in the plague high incidence area and resting area in the plague natural foci of Qingnan region in Qinghai Province, and to compare and analyze the differences of the contents of soil metal elements between the two areas.Methods:A total of 69 soil samples were collected from 11 sites in the plague high incidence area (Yushu Prefecture) and resting area (Guoluo Prefecture) in Qingnan region, including 39 samples from high incidence area and 30 samples from resting area. The contents of 12 soil metal elements, such as iron (Fe), magnesium (Mg), calcium (Ca), barium (Ba), cobalt (Co), copper (Cu), manganese (Mn), lead (Pb), rubidium (Rb), titanium (Ti), vanadium (V) and zinc (Zn), were measured by X-ray fluorescence spectrometry and SPSS 20.0 software was used for Spearman correlation and other statistical analysis.Results:The contents of Fe and Ca in the soil of the plague natural foci of Qingnan region were relatively high. The contents of 12 soil metal elements in the high incidence area were significantly higher than those in the resting area ( P < 0.01 or < 0.05). There were statistical significant differences in the contents of Mg, Ca, Ba, Mn, Pb and Zn in the soil among the sample plots of the plague high incidence area ( P < 0.01 or < 0.05). There were statistical significant differences in the contents of Fe, Mg, Ca, Rb and Ti in the soil among the sample plots of the plague resting area ( P < 0.05 or < 0.01). Except for Mg and Ca, Fe was positively correlated with other metal elements in the high incidence area and resting area ( P < 0.01 or < 0.05), and Fe was strongly positively correlated with Rb, Ti and V ( r = 0.780 - 0.838). Mg was only positively correlated with Ca in the high incidence area and resting area ( P < 0.01). Ca was negatively correlated with Mn, Pb, Rb, Ti, V and Zn in the high incidence area, and with Rb and Zn in the resting area ( P < 0.01 or < 0.05). The rest of the metal elements were mostly positively correlated in the high incidence area and resting area. Conclusions:The contents of Fe and Ca are rich in the plague natural foci of Qingnan region in Qinghai Province. There are correlations among most soil metal elements in the high incidence area and resting area. The correlation between the contents of soil metal elements in the plague natural foci and the epidemic of plague is worth further exploring.

Objective:To understand the detection quality and external quality control assessment of fluorine and arsenic laboratories at all levels in Qinghai Province.Methods:Z-ratio scoring method was used to analyze and evaluate the results of provincial, municipal and county-level laboratories participating in the national fluorine and arsenic external quality control assessment from 2014 to 2020 in Qinghai Province, │Z│≤ 2 was qualified, 2 <│Z│ < 3 was basically qualified and│Z│≥ 3 was unqualified. At the same time, the feedback rate and pass rate of the participating laboratories were calculated.Results:From 2014 to 2020, the external quality control assessment results of water arsenic, urinary arsenic and brick tea fluorine in Qinghai Provincial laboratory were all qualified; except for the external quality control assessment of water fluorine in 2018 that was basically qualified, the results of other years were all qualified. Municipal and county-level laboratories did not give feedback the external quality control assessment results of water arsenic and urinary arsenic in 2017, and the feedback rate and pass rate in other years were 100.0%; except for the external quality control feedback rate and pass rate of water fluorine and brick tea fluorine in 2014 that were all 100.0%, there were laboratories that did not give feedback or failed the assessment in other years.Conclusion:The testing ability of provincial laboratory in Qinghai Province meets the standard, and the testing ability of municipal and county-level laboratories still need to be improved continuously.

Objective:To analyze the results of serum erythropoietin (EPO) in adults patients with Kaschin-Beck disease (KBD) in Qinghai Province.Methods:According to the "Diagnosis of Kaschin-Beck Disease" (WS/T 207-2010), by using clinical examination and X-ray, adults over 20 years old in KBD areas of Xinghai County and Guide County, Hainan Tibetan Autonomous Prefecture, Qinghai Province, were divided into KBD case group ( n = 109) and internal control group ( n = 95) in July 2019. At the same time, healthy people were selected as external control group ( n = 90) in Xunhua County. Then 2 ml fasting cubital venous blood was collected from the target population to separate serum. The serum EPO level was determined by enzyme-linked immunosorbent assay (ELISA). Results:There was no significant difference in age and sex ratio among the 3 groups ( F = 0.73, P = 0.484; χ 2 = 1.03, P = 0.611). There was significant difference in serum EPO levels among the 3 groups [KBD case, internal and external control groups: (30.74 ± 26.23), (19.73 ± 11.53) and (10.83 ± 4.48) U/L, F = 26.51, P < 0.001]. Multiple comparisons showed that there were statistically significant differences in serum EPO levels between KBD case group and the internal and external control groups ( P < 0.05), but there was no significant difference between the internal and external control groups ( P > 0.05). Conclusions:The serum EPO level in adult KBD patients in Qinghai Province is increased significantly.