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Objective To investigate the level of cadmium(Cd)in commercial aquatic products in Xiacheng District, Hangzhou. Methods We randomly collected 293 aquatic products which belonged to six aquatic animals in the markets in Xiacheng District to determine the content of Cd. It was further evaluated by single factor pollution index(PI)according to the standard GB 2762-2017. In 11 samples of swimming crabs, Cd was examined in the different parts. Results There was no significant difference in the content of Cd between the samples collected in the markets and those in the supermarkets. It significantly differed in the samples of different aquatic animals(P < 0.05). The prevalence of Cd that exceeded the standard was as follows: seawater crustaceans(28.6%) > cephalopods(11.1%) > freshwater crustaceans(8.4%) > bivalves(6.9%). However, it was not excessive in the samples of fish. The mean level of Cd in the seawater crustaceans was 0.466 3 mg/kg, which resulted in the proportion of the samples that were excessive being 28.6%. Particularly, the mean level in sea crab was as high as 1.101 mg/kg with the proportion being 66.7%. In the samples of swimming crabs, there was a significant difference in the prevalence of Cd between swimming crab gonads and crab chests or legs(P > 0.05), while no statistical difference between crab chests and legs(P > 0.05). Conclusion The content of Cd in the aquatic products may be excessive in Xiacheng District, which warrants additional regulatory efforts to food safety. The public should reduce the consumption of aquatic products with high content of Cd.
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Objective:To understand the risk of dietary lead exposure among adults in Xiacheng District of Hangzhou City. Methods:During 2013-2018， commercial foods were randomly collected in Xiacheng District of Hangzhou City for lead content testing. In combination with lead test result and dietary consumption data， the margin of exposure （MOE） method was used to assess the exposure risk of dietary lead. Results:A total of 827 samples from 14 kinds of commercial foods were collected， and the median of lead content was between 0.002 5 mg/kg and 0.100 0 mg/kg. The detection rate was 53.20%， and the over-standard rate was 1.09%. The median of daily dietary lead exposure among adults was 0.174 2 μg/kg BW， and the MOE value was 7.46. Vegetables and fruits were the dominant contributor to dietary intake of lead， accounting for 39.18% and 12.18%， respectively. Conclusion:The exposure of dietary lead among adults in Xiacheng District of Hangzhou City is at an acceptable level. The contribution of vegetables and fruits to dietary lead is higher than other foods， and needs more attention.
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Objective To investigate the status of occupational health surveillance in Xiacheng District of Hangzhou City from 2014 to 2017, and to provide basis for occupational hygienic supervision Methods Data on occupational health surveillance in Xiacheng District from 2014 to 2017 were collected, and the trend of occupational health surveillance was analyzed.The differences of occupational health surveillance among different hazardous agents, economic types, industries and scales were compared. Results There was no significant difference in rates of pre-job and on-job occupational medical examination from 2014 to 2017, and the rate of off-job occupational medical examination showed an increasing trend.There were statistical difference in on-the-job occupational medical examination rates among empolying units of different economic types, industries and scales.There were statistical differences in the detection rates of occupational contraindication among empolying units of different economic types, hazardous agents.There was no significant difference in the detection rates of suspected occupational diseases among empolying units. Conclusion The occupational health surveillance showed a phenomenon of "emphasizing on-the-job, neglecting pre-job and off-the-job" in Xiacheng District.Supervision department should pay more attention on manufacturing, collective and private economic.It is necessary to focus on the protection of staff contacts with chemical and physical agents. It is suggested that relevant departments should strengthen the propaganda and supervision of occupational health surveillance, according to the nature, characteristics of the employing units and types of their hazardous agents.
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<p><b>OBJECTIVE</b>To evaluate the effect of K2O addition on the crystallization property of dental glass-ceramics in the Li2O-SiO2-Al2O3-P2O5-ZnO system.</p><p><b>METHODS</b>Different content of K2O was added into Li2O-SiO2-Al2O3-P2O5-ZnO glass system. The heat-treated system of the glass-ceramics was determined by differential thermal analyses (DTA), then the crystallization components and the microstmcture of the glass-ceramics with different content of K2O were investigated from X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM).</p><p><b>RESULTS</b>Addition of K2O helped to reduce the viscosity of the glass system and improved crystallization. More lithium disilicate crystals appeared after heated-treatment of the glass system which contained 5.3 wt% addition of K2O, and the homogeneously lath-shaped crystals were 4 gm in length.</p><p><b>CONCLUSION</b>Certain content of K2O can improve the crystallization property of dental glass-ceramics in the Li2O-SiO2-Al2O3-P2O5-ZnO system.</p>