Abstract: To investigate the main occupational hazards of sand casting process enterprises, so as to provide insights into occupational disease prevention and control. Methods: In 2021 and 2022, six typical ferrous metal casting enterprises using sand casting technology in Wenling City, Zhejiang Province were selected to investigate the production processes and equipment, the operation of occupational disease prevention facilities and personal protective equipment. Occupational hazards including silica dust, noise, high temperature and ultraviolet radiation were detected and analyzed. Results: Six sand casting enterprises had not effectively set up and use occupational disease prevention equipment, and some employees had not worn personal protective equipment as required. The participation rate of occupational health examination was 100.00%. Among the 54 silica dust sampling points at the sand mixing, molding, sand falling, shot blasting and mud core drilling positions, the overall dust concentration exceeding the standard rate was 100.00%, and the respiratory dust exceeding the standard rate was 44.44%. Among the 55 noise measurement points at the sand mixing, sand falling, shot blasting, mud core drilling, polishing and blowing positions, 51 exceeded the standard, with a rate of 92.73%. Among the 90 sampling points for melting, painting, polishing, blowing and welding positions, the concentrations of welding fumes, manganese and its compounds, ethyl acetate and other cahmical factors did not exceed the standard. Six ultraviolet radiation measurement points in the welding position and six heat stress measurement points in the melting position did not exceed the standard. Conclusion The main occupational hazards of sand casting process enterprises in Wenling City are silica dust and noise, and occupational disease prevention and control should be further strengthened.

Objective To develop a method for determination of tin in the air of workplace by microwave digestion-HG-AFS. Methods The air samples were collected and the concentration of tin was determined by microwave digestion-HG-AFS and the parameters of atomic fluorescence spectrometry were studied. Results In the optimum condition, the detection limit of tin was 0.3 ?g /L, the lowest detected concentration of tin in the samples was 0.000 1 mg/m3 (based on 75 L air sample), the RSD was 2.7%-3.5%, the rate of recovery was in the range of 96.5%-104.7%. Conclusion The method is rapid, convenient, accurate, sensitive and suitable for determination of tin in the air of workplace.

Objective To establish a HG-AFS method for determination of cadmium in the water. Methods The condition for hydride generation and parameters of atomic fluorescence spectrometry were studied. Results In the optimum condition, the detection limit of tin was 0.03 ?g /L, the RSD were 1.1%-3.0%. The sample recoveries were 98.2%-107.0%. Conclusion The method is rapid, convenient, accurate, sensitive and suitable for determination of cadmium in the water.

Objective To evaluate the effectiveness of web-based mental health services.Methods Web-based mental health services were established in our hospital to offer continuing medical education on mental health and psychological assessments.The access of clinicians to psychiatric knowledge and consultation from psychiatry department was evaluated.Results A total of 803 medical staff took the continuing medical education,and 643 passed the examination.Five hundred and twenty-eight online psychological assessments were completed.The qualification rate of psychiatric examination was 83.3％ vs.31.7％ in educated and non-educated clinicians (x2=32.77,P＜0.01).The common consultation from psychiatry department of the educated group involved anxiety,depression/mania and delirium,of which anxiety and medically unexplained symptoms were comparatively higher while delirium was lower than the non-educated group (x2 values were 4.80,4.59 and 5.16,respectively; all P＜0.05).More use of online psychological assessments was found in the educated group (33.8％ vs.7.6％) before asking for a consultation from psychiatry department (x2=30.04,P＜0.01).Conclusions Online mental health continuing education and psychological assessment could improve psychiatric knowledge and recognition of anxiety and depression in clinicians.