College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China.
West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
Sci Total Environ. 2024 Nov 15;951:175524. doi: 10.1016/j.scitotenv.2024.175524. Epub 2024 Aug 20.
Cyclic methylsiloxanes (CMSs), widely found in wastewater treatment plants (WWTPs), are potentially hazardous to the environment and human health. In this study, the environmental behavior and human exposure risks of three CMSs (D4-D6) were evaluated in WWTPs located in Beijing and Kunming, Yunnan province. D5 had the highest concentrations in air, water, and sludge, with seasonal variation that consisted of a high concentration in summer and low concentration in winter. The CMS concentrations in air were 3-4-fold higher in the A/O (Anaerobic-Anoxic-Oxic) treatment units than in the other units. CMS emissions to air, soil, and water from the Beijing WWTP were in the ranges of 3.4 × 10-5.0 × 10 kg·a, 4.5 × 10-7.5 × 10 kg·a, and 2.5 × 10-2.9 × 10 kg·a, constituting 98 %, 1.3 %, and 0.7 % of the total emissions, respectively. Total daily inhalation exposure doses of CMSs (ADD) associated with four different jobs in WWTPs showed that wastewater treatment technicians had the highest ADD (51 μg/kg/day), indicating that these people had the highest occupational exposure risk in WWTPs. Therefore, this study identified that atmospheric emission was the main environmental fate of CMSs in WWTPs, and provide a basis for the improvement of WWTP process and risk management decisions. ENVIRONMENTAL IMPLICATION: Assessing the environmental fate and occupational exposure risk of cyclic methylsiloxanes (CMSs) found in wastewater treatment plants (WWTPs) is crucial. This is the first study to identify that atmospheric emission was the main environmental fate of CMSs in WWTPs, especially D5; the inhalation exposure doses of CMSs were all significantly higher in the occupational population working in WWTPs. The results described in our study will help enhance the understanding of current knowledge base of environmental fate and exposure risk of CMSs in WWTPs, and provide a basis for the improvement of WWTP process and risk management decisions.
环状甲基硅氧烷（CMSs）广泛存在于污水处理厂（WWTPs）中，对环境和人类健康具有潜在危害。本研究评估了三种 CMSs（D4-D6）在北京和云南昆明的 WWTP 中的环境行为和人体暴露风险。D5 在空气、水和污泥中的浓度最高，季节性变化表现为夏季浓度高，冬季浓度低。A/O（厌氧-缺氧-好氧）处理单元中空气的 CMS 浓度比其他单元高 3-4 倍。北京 WWTP 向空气、土壤和水中排放的 CMS 分别在 3.4×10-5.0×10kg·a、4.5×10-7.5×10kg·a 和 2.5×10-2.9×10kg·a 范围内，分别占总排放量的 98%、1.3%和 0.7%。WWTP 中四种不同工作岗位的 CMS 总日吸入暴露剂量（ADD）表明，污水处理技术员的 ADD 最高（51μg/kg/天），表明这些人在 WWTP 中面临最高的职业暴露风险。因此，本研究确定了大气排放是 CMSs 在 WWTP 中的主要环境归宿，为改进 WWTP 工艺和风险管理决策提供了依据。环境影响：评估污水处理厂（WWTPs）中环状甲基硅氧烷（CMSs）的环境归宿和职业暴露风险至关重要。这是首次确定大气排放是 WWTP 中 CMSs 的主要环境归宿的研究，特别是 D5；在 WWTP 工作的职业人群中，CMSs 的吸入暴露剂量均显著较高。我们研究中描述的结果将有助于增强对 WWTP 中 CMSs 环境归宿和暴露风险的现有知识基础的理解，并为改进 WWTP 工艺和风险管理决策提供依据。
