ABSTRACT
OBJECTIVE: To formulate a limit of occupational benzoquinone in the air of workplace. METHODS: According to GBZ/T 210. 1-2008 Guide for Establishing Occupational Health Standards--Part 1: Occupational Exposure Limits for Airborne Chemicals in the Workplace,the relevant literatures on toxicology,epidemiology and foreign occupational exposure limit for benzoquinone were collected and analyzed. A benzoquinone production enterprise was selected as the research subject. Occupational hygiene investigation and occupational epidemiological investigation were carried out. The occupational exposure limit of benzoquinone in the air of workplace was assessed. RESULTS: The literature data analysis results showed that benzoquinone is a highly toxic substance,has strong stimulated effect on human respiratory tract,eyes and skin. The occupational exposure limit of benzoquinone in the workplace air in the United States of America,Germany and Australian is 0. 400 mg/m~3. In the benzoquinone production enterprise,the median of concentration-time weighted average of benzoquinone exposed workers( exposure group) was 0. 100 mg/m~3. The median of concentration-short term exposure limit in the workplace air was 0. 160 mg/m~3. There was no significant difference on the abnormal detection rate of conjunctivitis,dermatitis,and abnormal liver B type and abnormal kidney B type ultrasound between the exposure group and the control group( P > 0. 05). There was no significant difference on the serum liver function and renal function indexes between the two groups( P > 0. 05). The results of blood routine examination in the two groups were within the normal reference range. CONCLUSION: It is suggested that the permissible concentration-time weighted average of benzoquinone in the workplace air should be set at 0. 400 mg/m~3 in China.
ABSTRACT
ObjectiveTo study the diagnosis of thyroid cancer concurrent with multiple thyroid nodules.Methods The clinical data of 23 patients of multiple thyroid nodules with thyroid cancer undergoing exploration from May 1988 to December 2000 were analyzed retrospectively.ResultsThe diagnosis of concurrent carcinoma was made preoperatively in 6 cases. 13 out of the 23 patients underwent second operation for the postoperative pathology being malignant. Thyroid cancer was identified concurrent with benign nodules in 20 cases. Conclusion Thyroid cancer when found on the background of multiple thyroid nodules is often coexistant with benign thyroid disease, hence the diagnosis is difficult to make clinically. Second operation is sometimes inevitable when the pathology identified a cancer in preoperatively diagnosed benign nodules.