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Objective To investigate the content and changes of fluoride in corn and pepper, to evaluate the effect of prevention and control measures, and to provide a basis for adjusting the prevention and control strategy. Methods In 2013, according to the different directions of east, west, south, north and center, 5 townships were selected from each coal-burning-borne endemic fluorosis areas in all 23 counties (cities, districts), and 3 villages was randomly selected from each township. Household samples of corn and dried pepper in 10 households were collected to detect fluorine content. The results of 14 counties were compared with the 2007 survey data. Results A total of 884 and 3379 samples of corn and pepper were collected, and the median fluorine content was 1.26 and 9.15 mg/kg, the range was 0.50~254.59 mg/kg and 0.50~3701.88 mg/kg, respectively. Compared with the survey data of 2007, the median fluoride content of corn of 14 counties decreased by nearly 50%, and the median amount of pepper was reduced by more than 80%. The differences were statistically significant (mg/kg:corn 1.36 vs 2.63, dried pepper 9.70 vs 55.31, Z = 3.28, 9.13, P<0.05). Conclusion The fluoride content of corn and pepper in Guizhou Province is significantly lower, but it is still relatively high in some coal-burning-borne fluorosis counties (cities, districts).
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Objective To apply hydride generation atomic fluorescence spectrophotometry (HG-AFS method) in urinary arsenic detection,and to provide a better,newer and more convenient detection method for quantitative analysis of urinary arsenic.Methods According to the Guide to Develop Biological Sample Inspection Method(WS/T 68-1996) and Guide for Establishing Occupational Health Standards-part 5:Determination Methods in Biological Materials (GB/T 210.5-2008),HG-AFS method was established to detect arsenic content in urine after modification of the method for sample pretreatment,and to verify the linear range of standard curve and linearity,detection limit,precision,accuracy,stability of the sample,and to compare the experimental results of HG-AFS method with those of standard methods of WS/T 28-1996 and Determination of Arsenic in Urine by Cyanide Generation Atomic Fluorescence Method (WS/T 474-2015).Results The HG-AFS method linear range was from 0-100 μg/L,the correlation coefficient r =0.999 9,the detection limit was 0.07 μg/L,the precision was 1.96％-3.97％,and the recovery rate was 95.1％-105.0％.There was no statistical significance between HG-AFS method,the standard of WS/T 28-1996 or WS/T 474-2015 methods (t =1.539,0.353,all P ＞ 0.05).Conclusion The new method is superior to the current detection method owing to its low detection limit,high precision,good accuracy,and wide linear range.
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Objective To understand the quality of blood slide-making and the ability of films reading in Guizhou,in order to strengthen the detection ability on Plasmodium.Method The quality of blood slide-making and the medical result were assessed by re-checking all the 609 blood samples of network reported cases and a part of negative cases from 2012 to 2014 according to Technical Plan of Eliminating Malaria (2011) and Diagnostic Criteria of Malaria (WS 259-2006).Results The blood slide-making,stain,blood slice cleanliness were 48.93％ (298/609),62.56％ (381/609) and 55.50％ (338/609),respectively.The diagnostic coincidence rate was 94.91％ (578/609),and the diagnostic coincidence rate of the positive cases and the negative cases were 73.77％ (45/61) and 98.72％ (541/548).Conclusion The diagnostic coincidence rate is satisfied in Guizhou.But the microscopy quality of Malaria parasite should be improved.
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Objective To analyze the quality control measures on urinary fluoride testing in the implementation,and to provide experience in quality control for testing activities.Method According to the Determination of Fluoride in Urine-Ion Selective Electrode Method (WS/T 89-1996),focusing on ways to complete testing all the samples in a short time,implementing internal quality control measures in the testing before,during and after the implementation by different ways as blank experiment,standard substance detection,personnel parallel experiment,paralleled detection,instrument comparison and sample test repeat,were carried out.Results The test results of blank experiment were lower than the lowest detection limit;the test results of standard material were within the scope of the standard reference,there was no significant difference between the mean value and the reference value (t =0.01,0.00,0.02,all P ＞ 0.05),|Z| values were all less than 1;the results of personnel parallel experiment,paralleled detection,instrument comparison test results and sample test repeat were not significantly different statistically (all P ＞ 0.05);the results of instrument comparison and sample test repeat were not significantly different statistically (t =0.129,0.034,all P ＞ 0.05).A total of 9 123 urine samples were tested,the geometric mean of urinery fluoride was 0.58 mg/L.Conclusion Different quality control measures should be implemented through all the testing,control personnel errors,instruments,and reagents,etc,to ensure the quality of the entire test results.
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Objective To evaluate the urinary fluorine detection quality of endemic fluorosis monitoring network laboratories in Guizhou Province and promote the improvement of quality control.Methods From 2010 to 2012,according to the method for determination of fluoride in urine by ion selective electrode,in 11 endemic fluorosis monitoring network laboratories in Guizhou,an quality control assessment was done.In the internal quality control assessment,standard substance detection inspection was used for personnel parallel samples and equipment comparison,t test was used to compare the inter-group differences.In the external quality control inspection,blind urine fluorine sample was tested,and a Z score value evaluation method was used to compare the relative error of the test results.Results In the assessment of internal quality control,the parallel comparison test results of sample,personnel and instrument showed that the differences were not statistically significant (t =-1.81-1.80,P ＞ 0.05).In 2010,in the external quality control inspection,there was 1 laboratory |Z|≥3,and 2 test results |Z| ＞2;in 2011,there was 4 test results |Z| ＞ 2;in 2012,there was 5 test results |Z| ＞ 2;in 2010,there was one laboratory in a blind test,relative error of the results ＞ 20％;in 2011 and 2012,there was a laboratory in a blind test,relative error of the results ＞ 10％.Conclusion The endemic fluorosis monitoring network laboratory testing ability in Guizhou is relatively good,but there is an obvious individual laboratory system error.