隧道工人的PM10职业暴露特征调查分析及其健康风险评价

针对隧道工人职业健康风险缺乏定量评价方法的现状,借鉴公共环境健康领域暴露评价模型对隧道施工PM10职业暴露的健康风险进行定量评价.设计职业暴露问卷对湖北麻竹高速公路某标段施工中的250名隧道工人进行了调查,并对现场PM10浓度水平进行了监测.结果表明,隧道工人的PM10暴露浓度水平相当高,开挖工、爆破工、支护工、出渣工、二衬工的PM10暴露浓度分别为限值的83倍、18倍、8倍、9倍和9倍;5个工种比较,二衬工日均暴露时间最长,达11.48 h·d-1,能量代谢率最高,达1 067.43 k J·(m2·h)-1,呼吸速率的计算结果显示除二衬工属于重度活动以外,其他4个工种均为中度活动;评价结果显示5个工种均存在健康风险,其中,PM10暴露浓度高是开挖工和爆破工危险系数高的主要原因,而二衬工危险系数高的原因则在于高劳动强度所致的较高的呼吸速率以及较高的日均暴露时间.降低隧道工人PM10健康风险可行的途径是通过配备合适劳动作业的呼吸防护用品从而降低PM10暴露浓度,另外可通过制定相应的职业规范设置合理的劳动年限从而减少持续暴露时间.

Health Risk Assessment of Tunnel Workers Based on the Investigation and Analysis of Occupational Exposure to PM10

The health risk of tunnel workers' occupational exposure to PM₁₀ was evaluated applying public health exposure evaluation model. A questionnaire survey of 250 tunnel workers was conducted in a construction site of Ma-zhu Highway in Hubei Province, and the concentrations of PM₁₀ were monitored. The results showed that the PM₁₀ exposure concentrations of different types of tunnel workers were extremely high. Compared with the limited value, the PM₁₀ exposure concentrations were 83 times, 18 times, 8 times, 9 times and 9 times for excavation workers, blasting workers, supporting workers, slag-out workers and secondary-lining workers, respectively. For secondary-lining workers, the average daily exposure time was the longest, which was 11.48 h·d^-1, and the energy metabolism rate was also the highest, which was 1067.43 kJ·(m²·h)^-1. Regarding the inhalation rates, secondary-lining workers could be classified to high-level working intensity, and the other four types of tunnel workers could be classified to middle-level working intensity. The health risk assessment results showed that all tunnel workers had health risk. High exposure concentration of PM₁₀ was the main reason for excavation workers' highest hazard quotient, and it was the same for the blasting workers. The reason for secondary-lining workers' high hazard quotient was that they had higher inhalation rates and longer average daily exposure time. In order to reduce the health risk of tunnel workers, firstly the workers should be equipped with appropriate respiratory protective equipment; secondly an appropriate tunnel working standard should be developed to set a reasonable working-years for reducing the exposure time.