1.Advance of methodology for determination of 226Ra
CAO Yiyao ; REN Hong ; GU Wenhao ; LOU Xiaoming
Journal of Preventive Medicine 2021;33(8):789-792
Abstract
Recent years have witnessed more attention paid to the health effects of the natural radionuclide 226Ra, and a series of research carried out on the detection methods of 226Ra at home and abroad. The common 226Ra detection methods are emanation scintillation, gamma spectrometry, liquid scintillation counting, alpha spectrometry and alpha counting. Emanation scintillation is mature enough as a classical method, while gamma spectrometry and liquid scintillation counting proceed fast. Due to the radiation of 226Ra, these detection methods still have the problems such as the requirement for large samples, long detection periods, complicated steps, high detection limits and low recovery rates. This paper reviews the five methods above and summarize their advantages and disadvantages, so as to provide the reference for selecting and optimizing the detection methods for different samples as well as perfecting the standard method in China.
2.Comparison of five occupational health risk assessment models applied to silica dust hazard in small open pits
XU Qiuliang ; CAO Yiyao ; WANG Peng ; REN Hong ; YUAN Weiming ; LI Fei ; ZHANG Meibian
Journal of Preventive Medicine 2021;33(9):873-876
Objective:
To quantitatively compare five occupational health risk assessment models in assessing silica dust hazard risk in small open pits, so as to provide the reference for the research of occupational health risk assessment methodology
Methods :
Seven small open pits were selected as the evaluation sites. The models from Singapore, the United Kingdom's Control of Substances Hazardous to Health Essentials ( COSHH Essentials ), Australia, Romania, and the International Council on Mining and Metals ( ICMM ) were applied to assessing the occupational health risk of the workers exposed to silica dust. The risk ratios ( RRs ) were calculated, and the parallelism, accuracy and correlation of the evaluation results of the five models were compared.
Results :
The RRs of the Singaporean model, COSHH model, Romanian model, Australian model and ICMM model were 0.8, 1.0, 0.4, 0.6 and 0.8, respectively. The Singaporean model and the Australian model were able to distinguish transport drivers from sprinkler drivers in the health risk exposed to silica dust, which was consistent with the actual risk of the two posts. Except for COSHH model, the RRs of the other four models were positively correlated ( P<0.05 ); the RRs were all positively correlated with concentration ratios ( CRs ) ( P<0.05 ), and the correlation coefficient between RRs and CRs of the Singaporean model was the largest (0.801).
Conclusion
Among the five models, the Singaporean model can more accurately evaluate the hazard risk of silica dust in posts of open pits, and has a good correlation with the other models.
3.Study on rapid microwave-ashing pretreatment method for radioactivity monitoring in food
Yiyao CAO ; Shunfei YU ; Zhiqiang XUAN ; Xinxing LI ; Yaoxian ZHAO ; Jin LUO ; Yihua LI ; Xiaoming LOU
Chinese Journal of Radiological Medicine and Protection 2018;38(1):43-47
Objective To establish a rapid,high-efficiency and clean way to monitor and pretreat the radioactivity in foods.Methods Food samples,20 kg each of cabbage,crucian,shrimp,pork and 20 L of milk,were collected around Qinshan nuclear power plant,totaling 10 samples for each food.Each type of foods was arranged in two groups each with 10 samples.Samples were pretreated using traditional ashing method (TAM) and microwave ashing method (WAM) separately.HDEHP were used for 90Sr separation and measurement.Calculations were made for the time spent on food pretreatment.The ash-fresh ratio and the recovery rate of 90Sr by the two different method were calculated,with the quality of ash being evaluated.Results The mean time spent on pretreatment was cabbage 20 h,crucian 54 h,shrimp 46 h,pork 58 h and milk 74 h for TAM group,and cabbage 8.5 h,crucian 26 h,shrimp 23 h,pork 26 h and milk 30 h for WAM group,respectively.The time spent by WAM was half the time less than by TAM,especially for animal edible product.The ash-fresh ratios from WAM group were higher than from TAM group.The recovery rates of 90Sr from WAM group in the analytical process were all above 75%,higher than from TAM group.Ashes produced by WAM were hoary,uniform,carbon residue-free and fully ashed.Conclusions WAM pretreatment can pretreat food rapidly,efficiently,cleanly with less loss and better ashing effect.These can meet the requirement of rapid pretreatment of radioactivity in food.
4.Determination of acrylic acid in workplaceair by on-line methylationgas chromatography
Peng WANG ; Hong REN ; Zhen ZHOU ; Yong HU ; Kang ZHENG ; Yiyao CAO
Chinese Journal of Industrial Hygiene and Occupational Diseases 2020;38(12):935-937
Methods:the samples were absorbed by solvent desorption silica gel tube and desorbed by methanol. Desorption fluid in the injector at 350 ℃ in the presence of an organic alkali tetramethylamine hydroxide (TMAH, 25% methanol) , allowed quantitative analysis of acrylic acid as its corresponding methyl derivative by gas chromatography.Results:calibration curve of the method was linear within the range 0-258.4 mg/L and showed good linearity with r=0.999 4. The determination limit of the method was 0.9 mg/L, and the minimum detection concentration was 0.06 mg/m 3 (collect 15 L air) . The relative standard deviation ( RSD) was 2.2%-2.7% ( n=5) . Recoveries were between 96.9-101.6%. Conclusion:the results prove on-line methylation gas chromatography is an accurate, simple and high sensitive method for determining acrylic acid in workplace air.
5.Determination of chloroacetic acid in workplace air by silanization-gas chromatography
Peng WANG ; Hong REN ; Qiuliang XU ; Yiyao CAO
Chinese Journal of Industrial Hygiene and Occupational Diseases 2021;39(4):299-302
Objective:A method to determine acrylic acid in workplace air was developed by silanization-gas chromatography.Methods:In March 2020, chloroacetic acid in air were absorbed by silica gel tube, the samples were dried, then were desorbed and silanized by acetonitrile: N, O-bis (trimethylsilane) trifluoroacetamide (2∶1, V/V) at room temperature, allowed quantitative analysis of chloroacetic acid as its silanization product by gas chromatography.Results:Calibration curve of the method was linear within the range 0-162.8 μg/ml and showed good linearity with linear equation: y=0.011 8 x, r=0.999 7. The determination limit of the method was 0.8 μg/ml, and the minimum detection concentration was 0.05 mg/m 3 (collect 15 L air) . The relative standard deviation ( RSD) was 0.5%-1.3% ( n=5) . Recoveries were between 98.6%-101.2%. Conclusion:The results prove silanization-gas chromatography is an accurate, simple and high sensitive method for determining chloroacetic acid in workplace air.
6.Determination of acrylic acid in workplaceair by on-line methylationgas chromatography
Peng WANG ; Hong REN ; Zhen ZHOU ; Yong HU ; Kang ZHENG ; Yiyao CAO
Chinese Journal of Industrial Hygiene and Occupational Diseases 2020;38(12):935-937
Methods:the samples were absorbed by solvent desorption silica gel tube and desorbed by methanol. Desorption fluid in the injector at 350 ℃ in the presence of an organic alkali tetramethylamine hydroxide (TMAH, 25% methanol) , allowed quantitative analysis of acrylic acid as its corresponding methyl derivative by gas chromatography.Results:calibration curve of the method was linear within the range 0-258.4 mg/L and showed good linearity with r=0.999 4. The determination limit of the method was 0.9 mg/L, and the minimum detection concentration was 0.06 mg/m 3 (collect 15 L air) . The relative standard deviation ( RSD) was 2.2%-2.7% ( n=5) . Recoveries were between 96.9-101.6%. Conclusion:the results prove on-line methylation gas chromatography is an accurate, simple and high sensitive method for determining acrylic acid in workplace air.
7.Determination of chloroacetic acid in workplace air by silanization-gas chromatography
Peng WANG ; Hong REN ; Qiuliang XU ; Yiyao CAO
Chinese Journal of Industrial Hygiene and Occupational Diseases 2021;39(4):299-302
Objective:A method to determine acrylic acid in workplace air was developed by silanization-gas chromatography.Methods:In March 2020, chloroacetic acid in air were absorbed by silica gel tube, the samples were dried, then were desorbed and silanized by acetonitrile: N, O-bis (trimethylsilane) trifluoroacetamide (2∶1, V/V) at room temperature, allowed quantitative analysis of chloroacetic acid as its silanization product by gas chromatography.Results:Calibration curve of the method was linear within the range 0-162.8 μg/ml and showed good linearity with linear equation: y=0.011 8 x, r=0.999 7. The determination limit of the method was 0.8 μg/ml, and the minimum detection concentration was 0.05 mg/m 3 (collect 15 L air) . The relative standard deviation ( RSD) was 0.5%-1.3% ( n=5) . Recoveries were between 98.6%-101.2%. Conclusion:The results prove silanization-gas chromatography is an accurate, simple and high sensitive method for determining chloroacetic acid in workplace air.
8.Impact of water supply from Qiandao Lake on gross radioactivity level in drinking water in downtown Hangzhou
Hong REN ; Yiyao CAO ; Peng WANG ; Hua ZOU ; Shunfei YU ; Bing ZHU ; Dongxia ZHANG ; Zhiqiang XUAN ; Yaoxian ZHAO
Chinese Journal of Radiological Medicine and Protection 2022;42(6):438-442
Objective:To investigate the levels of gross radioactivity in drinking water in Hangzhou city before and after Qiandao Lake as the water source to the main urban area of Hangzhou.Methods:Since 2012, water samples were collected from water source, factory water and peripheral water in rainy and dry seasons, respectively, to determine their gross α and β activity concentrations for comparison and analysis.Results:The gross radioactivity levels in drinking water in Hangzhou are lower than the limits specified in the national standard "Standards for drinking water quality" (GB 5749-2006), without statistically significant difference for these water sources between the rainy and dry season ( P>0.05). The gross α(0.008±0.000)and gross β(0.034±0.013)levels in Qiandao lake were both less than those in Qiantang river ( Z=-3.235, -4.058, P<0.05), with significant difference ( Z=-2.181, -4.577, P<0.05). There was no significant difference in gross α and gross β in factory water and peripheral water before and after the operation of Qiandao Lake water supply project ( P>0.05). Conclusions:The gross radioactivity in drinking water in downtown Hangzhou are low from 2012 to 2020. The gross radioactivity levels in Qiandao Lake are lower than in the lower reaches of Qiantang river and Dongtiao steam. No impact was generated on radioactivity levels in drinking water after Qiandao lake supplied water to Hangzhou.
9.Investigation on total radioactivity in drinking water following operation of the second phase expansion project at Qinshan Nuclear Power Plant
Lei ZHOU ; Yiyao CAO ; Hong REN ; Peng WANG ; Hua ZOU ; Shunfei YU ; Yaoxian ZHAO ; Zhiqiang XUAN ; Zhongjun LAI ; Dongxia ZHANG
Chinese Journal of Radiological Medicine and Protection 2023;43(12):1003-1009
Objective:To investigate and analyze the level of the gross radioactivity, and its variation trend, in surrounding drinking water since the second phase expansion project at Qinshan Nuclear Power Plant was officially put into operation.Methods:From 2010 to 2022, the source water, factory water and tap water within 30 km of Qinshan Nuclear Power Plant were collected in the flood season (May) and dry period (October) every year. The total α and total β radioactivity concentrations in drinking water was measured and analyzed. The levels of total radioactivity in drinking water around different nuclear power plants in China and around non-nuclear power plant areas was compared.Results:The mean radioactivity concentrations of total α and total β were (0.021±0.019) and (0.204±0.058) Bq/L in source water, (0.010±0.005) and (0.185±0.056) Bq/L in factory water , and (0.012±0.007) and (0.170±0.058) Bq/L in tap water, respectively, all lower than the limits stipulated in the Sanitary Standards for Drinking Water. There were no significant differences in the monitoring result of betweem the three types of water samples both in the flood and dry periods ( P> 0.05). The total radioactivity level in drinking water around Qinshan Nuclear Power Plant site was close to that in drinking water around different nuclear power plants in China and around areas without nuclear power plants. Conclusions:Following the second phase of the expansion project officially being put into operation, the total α and β radioactivity level in drinking water around the Qinshan Nuclear Power Plant has been in a stable trend and lower than the guidance level given in national standard.
10.Investigation on 90Sr level in offshore seawater and seafood therein around Sanmen nuclear power plant site and assessment of committed effective dose from 2015 to 2019
Yiyao CAO ; Dong ZHAO ; Shunfei YU ; Meibian ZHANG ; Hua ZOU ; Zhiqiang XUAN ; Zhongju LAI ; Yaoxian ZHAO ; Peng WANG ; Hong REN
Chinese Journal of Radiological Medicine and Protection 2021;41(4):288-292
Objective:To investigate and analyze the radioactivity level of 90Sr in offshore seawater and seafood therein around Sanmen nuclear power plant (NPP) and to estimate the annual committed effective dose to local population from ingestion of 90Sr in seafood from 2015 to 2019. Methods:From 2015 to 2019, the offshore seawater and 3 kinds of marine products grown locally in Sanmen and consumed by local residents were collected for measurement of the level of 90Sr radioactivity. The committed effective doses to the local population were estimated based on monitoring result and consumption data on seafood in Zhejiang offshore. Results:The radioactivity concentrations of 90Sr ranged from 2.4 to 4.1 mBq/L in the seawater, close to the natural radioacrive background level and from 6.7×10 -2 to 1.3 Bq/kg in seafood, lower than the standard values specified in the "Limited concentrations of radioactive materials in foods" (GB 14882-94). Annual committed effective dose to the local population from 90Sr attributable to consumption of seafood in Sanmen County from 2015 to 2019 were 2.2×10 -4-4.2×10 -4mSv, respectively, far lower than the worldwide committed effective dose result ing from internal exposure. Conclusions:From 2015 to 2019, the radioactivity concentration of 90Sr in seawater and seafood are stable, with neglectable dose burden to the local population.