Cui Beibei, An Dongzi, Li Haojun, Luo Xi, Zhu Hao, Li Ming, Ai Xiaojun, Ma Jiaxin, Ali Wajid, Yan Cheng
School of Environmental Studies, China University of Geosciences, Wuhan 430074, PR China; Hubei Key Laboratory of Environmental Water Science in the Yangtze River Basin, China University of Geosciences, Wuhan 430074, PR China.
China Construction Eco-Environmental Group Co., Ltd, Beijing 100037, PR China.
J Hazard Mater. 2023 Jun 15;452:130687. doi: 10.1016/j.jhazmat.2022.130687. Epub 2022 Dec 27.
Agitation operations produce numerous pathogenic bioaerosols in WWTPs. QMRA can determine risks of persons exposed to these bioaerosols. However, QMRA framework cannot help stakeholders in immediately deciding whether a risk is intolerable. Thus, evaluating threshold of acceptable exposure concentration is an urgent issue but is still rarely addressed in WWTPs. This study analyzed TLV benchmarks of E. coli and S. aureus bioaerosols emitted from a WWTP by reverse-QMRA. Furthermore, variance of input parameters was clarified by sensitivity analysis. Results showed that, under conservative and optimistic estimates, TLV of technicians was 1.52-2.06 and 1.26-1.68 times as large as those of workers, respectively; wearing mask drive TLV up to 1-2 orders of magnitude; TLV of M was at most 1.33 and 1.31 times as large as that of RD, respectively. For sensitivity analysis, removal fraction by equipping PPE enlarge TLV for effortlessly obtaining an acceptable assessment result; exposure time was dominant when without PPE excepting the scenario of technicians exposed to E. coli bioaerosol. This study helps establish threshold guidelines for bioaerosols in WWTPs and contribute innovative perspectives for stakeholders.
污水处理厂的搅拌作业会产生大量致病性生物气溶胶。定量微生物风险评估（QMRA）可以确定接触这些生物气溶胶的人员所面临的风险。然而，QMRA框架无法帮助利益相关者立即确定某种风险是否不可接受。因此，评估可接受暴露浓度的阈值是一个紧迫的问题，但在污水处理厂中仍然很少得到解决。本研究通过反向QMRA分析了某污水处理厂排放的大肠杆菌和金黄色葡萄球菌生物气溶胶的阈限值基准。此外，通过敏感性分析明确了输入参数的方差。结果表明，在保守估计和乐观估计下，技术人员的阈限值分别是工人的1.52 - 2.06倍和1.26 - 1.68倍；佩戴口罩可使阈限值提高1 - 2个数量级；M的阈限值分别最多是RD的1.33倍和1.31倍。对于敏感性分析，配备个人防护装备（PPE）后的去除率会增大阈限值，以便轻松获得可接受的评估结果；在不佩戴PPE的情况下，除了技术人员接触大肠杆菌生物气溶胶的情况外，暴露时间起主导作用。本研究有助于建立污水处理厂生物气溶胶的阈值指南，并为利益相关者提供创新观点。
