Comparison of occupational exposure limits of hexavalent chromium compounds in China and foreign workplaces / 中国职业医学

@#Objective To compare and analyze the occupational exposure limit（OEL）of hexavalent chromium compounds in China and foreign countries. Methods The OEL and background information of hexavalent chromium compounds released by nine official and unofficial organizations in seven countries/regions were collected and sorted. The classification，limit levels， formulation principles and compound characteristics labeling of OEL were compared. Results The OEL values published by nine organizations ranged from 0.000 02 to 0.050 00 mg/m3 . Among them，the limits of seven organizations（including China） did not clearly distinguish the soluble types of hexavalent chromium compounds；the limits of eight organizations（including China）were calculated in terms of chromium；seven organizations（including China）have only developed OEL for long-term exposure. The OEL of hexavalent chromium in China was 0.050 00 mg/m3 which is relatively loose. Its carcinogenicity label was consistent with international standards，its sensitization label was consistent with some countries，and its percutaneous absorption label had not been included in the characteristic labeling of limit values. Conclusion It is suggested that the OEL of hexavalent chromium in China should be revised timely，and the systemic adverse effects caused by percutaneous absorption of hexavalent chromium compounds should be focused on. At the same time，it is recommended to systematically adjust the management concepts and principles of all carcinogens.

Occupational exposure limit of trimethyltin chloride in workplace air / 中国职业医学

OBJECTIVE: To establish the occupational exposure limit for trimethyltin chloride(TMT) in workplace air. METHODS:According to the 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, population epidemiology and foreign occupational exposure limit of TMT were collected and analyzed. A total of 276 workers with TMT occupational exposure were selected as the exposure group and 25 workers without TMT occupational exposure were selected as the control group.Worksite survey of occupational health and occupational medical examination were carried out. Combined with the literature data, the occupational exposure limit of TMT in the workplace air was calculated by using the 90% medical reference level(internal exposure limit) of the urine TMT level of workers who exposed to TMT without moderate hypokalemia. RESULTS: The time-weighted average of TMT in the workplace air is 0.100 mg/m~3 and the short-term exposure limit is 0.200 mg/m~3 in the United States based on total organic tin. The highest concentration of TMT in the workplace air in Germany is 0.005 mg/m~3. The literature data analysis results showed that the incubation period of TMT poisoning is mostly 3-6 days, and the main symptoms of TMT poisoning are hypokalemia in the early stage, followed by neuropsychiatric symptoms such as headache, memory loss and aggressive behavior. The median(M) and the 0-100 th percentile(P_0-P_(100)) of exposure to TMT were 8.35(< 0.20-91.40) μg/m~3 in the exposure group. The individual TMT exposure level of workers in different positions from high to low were crushing, granulation, withdrawal and assembly positions. The M(P_0-P_(100)) of urinary TMT level in the exposure group was 16.94(<0.50-591.14) μg/L. There was a positive correlation between the individual TMT exposure level and urine TMT level in the exposure group(Spearman correlation coefficient=0.62, P<0.01). The detection rate of hypokalemia in the exposure group was higher than that in the control group(26.1% vs 4.0%, P < 0.05). However, there was no significant difference in the detection rate of moderate hypokalemia between the two groups(3.3% vs 0.0%, P>0.05). The 90% medical reference value of urine TMT was 89.90 μg/L in workers exposed to TMT without moderate hypokalemia. CONCLUSION: In order to prevent acute hypokalemia damage caused by TMT, we recommended that the occupational exposure limit of TMT in the workplace air should be set at 0.025 mg/m~3 in China, and this limit should be the maximum allowable concentration.

Occupational exposure limits of methyl t-butyl ether in workplace air / 中国职业医学

OBJECTIVE: To establish the occupational exposure limits for methyl t-butyl ether(MTBE) in the air of workplace in China. METHODS: According to the GBZ/T 210.1-2008 Guide for Establishing Occupational Health Standards--Part 1: Occupational Exposure Limits for Airborne Chemicals in the Workplace, we collected and analyzed data on physical and chemical properties, toxicology, occupational epidemiology and foreign occupational exposure limits related to MTBE by literature search. A total of 180 occupational workers exposed to MTBE were selected as exposure group, and 155 workers and administrative logistics personnel without exposure to MTBE were selected as the control group. Occupational hygiene investigation and occupational physical examination were carried out. We deduced the occupational exposure limits for MTBE in workplace air in China by combining literature data. RESULTS: The time-weighted average(TWA) of MTBE in the workplace air developed by the United States of America and Britain is 180.00 mg/m~3. The short-term exposure limit(STEL) of MTBE in the workplace air developed by Australia and New Zealand is 270.00 mg/m~3. The concentration of TWA(C_(TWA)) of MTBE in the exposure group was less than 0.08-4.90 mg/m~3. The concentration of short term exposure was less than 0.10-14.28 mg/m~3, and the C_(TWA) was less than 0.02-83.66 mg/m~3, in parts of workplaces. There was no statistically significant difference on the self-conscious discomfort and the abnormality in physical examination between these two groups(P>0.05). CONCLUSION: It's recommended that the permissible concentration-TWA of MTBE should be set at 180.00 mg/m~3, and the permissible concentration-STEL should be set at 270.00 mg/m~3 in China.

Study on occupational exposure limits of tributyl phosphate in the workplace air / 中华劳动卫生职业病杂志

Objective@#To put forward the suggestion of the occupational contact limit of tributyl phosphate in the air of the workplace.@*Methods@#Data of production and usage, workers' basic information, occupational history, and physical examinations were collected, and the environmental and individual levels of exposure were monitored using fixed-point and individual sampling. The results of the questionnaire and health examination were statistically analyzed using exact probability method of Fisher in the workers exposed to tributyl phosphate and the control group.@*Results@#The results showed that tributyl phosphate was widely distributed in the workplace of production and using enterprises, and the concentration of tributyl phosphate in packaging area was highest at 2.47 mg/m3, and in feeder nose was highest at 2.13 mg/m3. The discomfort symptoms were classified and results showed that tributyl phosphate exposure group of 136 people, all symptoms of 128 people, accounting for 94.44% of the total, the remaining 5.56% of the staff report had psychiatric symptoms or lethargy and irritability skin itching, the control group had no symptoms. There is or not discomfort symptoms in the tributyl phosphate exposure group and the control group was compared with the exact probability of Fisher, and the difference was statistically significant (P<0.05) . The results of healthy physical examination of workers exposed to tributyl phosphate and control group were statistically analyzed by the exact probability method of Fisher. The results showed that there was no significant difference in the results of routine internal medical examination, nervous system examination, skin examination, five senses examination, blood routine, urine routine, lung ventilation, and X ray chest fluoroscopy between the tributyl phosphate exposure group and the control group (P<0.05) .@*Conclusion@#The workplace permissible time-weighted tributyl phosphate and short-term exposure limit concentrations in China were set at 2.5 mg/m3 and 5 mg/m3, respectively.

Normas ocupacionais do benzeno: uma abordagem sobre o risco e exposição nos postos de revenda de combustíveis / Occupational regulation for benzene: an approach on risk and exposure in gas stations

Resumo Introdução: trabalhadores estão sujeitos a riscos decorrentes da exposição ambiental e ocupacional ao benzeno, situação ainda mais crítica quando associada a fatores como desigualdade social, múltipla exposição, suscetibilidade individual, degradação ambiental e às possíveis interações entre os contaminantes ambientais. Além disso, nem sempre as regulamentações são estabelecidas e/ou atualizadas apenas a partir de achados científicos, pois são processos permeados por conflitos de interesses. Objetivo: realizar análise crítica sobre a identificação de risco e avaliação da exposição ao benzeno. Métodos: revisão bibliográfica e documental do marco normativo brasileiro e internacional sobre exposição ao benzeno, com relação aos aspectos toxicológicos, de exposição ocupacional e ambiental e de avaliação de risco. Discussão: o controle da exposição ao benzeno permeia o campo da disputa técnico-política de saúde e segurança, constituindo-se em marco regulatório resultante de consenso de entendimentos. Esses entendimentos são marcados pela disputa entre a proteção à saúde e a gestão empresarial das condições de trabalho, em detrimento das evidencias científicas. Em tal contexto, os Limites de Exposição Ocupacional podem variar significativamente entre os países e agências, apesar do reconhecimento universal de que não há limites seguros para exposição ao benzeno, por ser um composto carcinogênico.

Abstract Introduction: workers are subject to risks from environmental and occupational exposure to benzene. This situation is even more critical when combined with social inequality, multiple exposure, individual susceptibility, environmental degradation, and possible interactions between environmental contaminants. In addition, regulations are not always established and/or updated only from scientific evidences, because they are processes permeated by conflicts of interest. Objective: to produce a critical analysis on risk identification and benzene exposure evaluation. Methods: literature and documentary review of the Brazilian and international regulatory standards on benzene exposure, toxicological aspects, occupational and environmental exposure, and risk evaluation. Discussion: benzene exposure control permeates the technical-political dispute of health and safety, resulting in a regulatory standard from consensus of understandings. These understandings are shaped by the dispute between health protection and business management of working conditions, to the detriment of scientific evidence. In this context, the Occupational Exposure Limits can vary significantly between countries and agencies, despite the universal recognition that there are no safe limits for benzene exposure, because it is a carcinogenic compound.

Limits of occupational benzoquinone exposure in workplace air / 中国职业医学

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.

Modelling levels of nitrous oxide exposure for healthcare professionals during EMONO usage

BACKGROUND: Computational fluid dynamics (CFD) has been used to compute nitrous oxide (N2O) levels within a room during the administration of an equimolar mix of N2O/oxygen (EMONO) in the clinical setting. This study modelled realistic scenarios of EMONO usage in hospital or primary care, in order to estimate the potential N2O exposure of healthcare professionals (HCP) with routine EMONO use and to provide guidance for EMONO users. METHODS: Sixteen scenarios were defined by carrying out a survey of practitioners. CFD simulations were performed for each scenario and N2O concentrations over time were calculated. N2O exposures (time-weighted average of concentration over 8 h [TWA-8 h]) were calculated at the HCPs’ mouth to be compared with a predefined occupational exposure limit (OEL). RESULTS: Administration duration and ventilation type were the main factors influencing N2O levels; ventilation type also influenced wash-out time between EMONO administrations. N2O concentration showed a plume distribution towards the ceiling and was highly heterogeneous, highlighting the importance of measurement location. Although estimated TWA-8 h varied widely, 13 of the 16 scenarios had an N2O TWA-8 h of <100 parts per million. CONCLUSIONS: Data demonstrate that EMONO usage in well ventilated rooms – as recommended – helps to ensure that N2O exposure does not exceed the OEL and does not signal any major risks for HCPs when recommendations are followed. Although these data are numerical simulations and should be considered as such, they can provide guidance for EMONO users.

Concepts of Occupational Exposure Limit and Their International Comparisons / 대한산업의학회지

This paper focuses on the origin of the concepts of occupational exposure limit, and traces the history and development of thoughts and regislations of various countries and organizations concerning the founding principles upon which it is based. The concepts of establishing standards for occupational chemicals in workplace air constitute a social consensus or agreement about acceptable levels of occupational hygiene. The level of scientific development of a country and the discussion of experts in the field of occupational health play an important role. The physician in occurational health has to be especially concerned to discover and estimate the risks to anyone particularly susceptible to exposures within the hygienically acceptable conditions.