ABSTRACT
OBJECTIVE: To quantitatively evaluate the non-carcinogenic and carcinogenic risks of low-level dichloromethane(DCM) exposure. METHODS: A typical sampling method was used to select workers from an engine factory and an automobile parts factory as the research subjects. After hazard identification and hazard characteristic assessment, the occupational health risks of DCM in the workplace were quantitatively assessed by non-carcinogenic risk assessment and carcinogenic risk assessment. RESULTS: The highest exposure concentration of short-term of DCM was 43.6 mg/m~3 in the air of eight DCM job posts in these two enterprises, which was lower than the operational level of 300.0 mg/m~3(half of the occupational exposure limit in China). Under this premise, the non-carcinogenic risk assessment results showed that the non-carcinogenic risk caused by inhalation of DCM was unacceptable in workers of these eight job posts. The results of carcinogenic risk assessment showed that the carcinogenic risk caused by inhalation of DCM was acceptable for all the workers in these eight job posts. CONCLUSION: Low-level DCM exposure can cause unacceptable occupational health risks to workers. Quantitative risk assessment can be applied to assess exposure to low-level chemicals.
ABSTRACT
OBJECTIVE: To establish a method for determination of urinary tin by atomic fluorescence spectrophotometry.METHODS: The graphite digestion instrument was used to digest 2. 50 m L urinary sample with 1. 50 m L concentrated nitric acid,hydrochloric acid( volume fraction 4. 00%) was added to a total constant volume of 10. 00 m L. After 2. 50 m L of thiocarbamide-ascorbic acid( mass concentration 100 g / L) was added,hydrochloric acid( volume fraction 4. 00%) was added to a total constant volume of 25. 00 m L( equivalent to urinary sample was diluted 10 times),1. 00 m L of the sample was collected and detected by atomic fluorescence spectrophotometry. RESULTS: The good linear relationship was shown in the range of 4. 00-200. 00 μg / L with a correlation coefficient of 0. 999 5. The limit of detection was 0. 20 μg / L. The recovery rates ranged from 100. 20% to 100. 84%. The within-run relative standard deviation( RSD) and between-run RSD were 0. 11%-2. 01% and 1. 37%-5. 58%,respectively. The samples can be stored for 7 days under the temperature of4 ℃. CONCLUSION: This method has the advantages of high sensitivity,precision and convenient operation,which is suitable for the daily determination of urinary tin in human.