Vo Phong H N, Key Trent A, Le Tu Hoang, McDonough Jeffrey T, Porman Scott, Fiorenza Stephanie, Nguyen Hong T M, Dao Vinh T N, Mueller Jochen F, Thai Phong K
Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, Queensland, 4102, Australia.
Climate Change Cluster, Faculty of Science, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia.
Water Res X. 2023 Aug 9;20:100195. doi: 10.1016/j.wroa.2023.100195. eCollection 2023 Sep 1.
Per- and polyfluoroalkyl substances (PFAS) within concrete pads impacted by historical firefighting training using aqueous film-forming foam (AFFF) may be potential secondary sources of PFAS due to surficial leaching. This study aimed to (i) characterize the effectiveness of two commercially available sealants (Product A and Product B) in mitigating leaching of five PFAS (e.g., PFOS, PFOA, PFHxS, PFHxA, 6:2 FTS) from concrete surfaces at the laboratory-scale, and (ii) develop a model to forecast cumulative leaching of the same five PFAS over 20 years from sealed and unsealed concrete surfaces. Laboratory trials demonstrated that both sealants reduced the surficial leaching of the five PFAS studied, and Product B demonstrated a comparatively greater reduction in surface leaching than Product A as measured against unsealed controls. The cumulative PFOS leaching from an unsealed concrete surface is estimated by the model to be about 400 mg/m over 20 years and reached asymptotic conditions after 15 years. In contrast, the model output suggests asymptotic conditions were not achieved within the modeled time of 20 years after sealing with Product A and 85% of PFOS was predicted to have leached (∼340 mg/m). Negligible leaching of PFOS after sealing with Product B was observed ( < 5 × 10 mg/m). Results from modeled rainfall scenarios suggest PFAS leachability is reduced from sealed versus unsealed AFFF-impacted concrete surfaces.
受历史上使用水成膜泡沫灭火剂（AFFF）进行消防训练影响的混凝土垫层中的全氟和多氟烷基物质（PFAS），由于表面淋溶，可能成为PFAS的潜在二次来源。本研究旨在：（i）在实验室规模下，表征两种市售密封剂（产品A和产品B）减轻五种PFAS（如全氟辛烷磺酸、全氟辛酸、全氟己烷磺酸、全氟己酸、6:2氟调聚物磺酸）从混凝土表面淋溶的效果；（ii）建立一个模型，预测这五种PFAS在20年内从密封和未密封混凝土表面的累积淋溶情况。实验室试验表明，两种密封剂都减少了所研究的五种PFAS的表面淋溶，与未密封对照相比，产品B在表面淋溶减少方面表现出相对更大的效果。该模型估计，未密封混凝土表面在20年内全氟辛烷磺酸的累积淋溶量约为400毫克/平方米，15年后达到渐近状态。相比之下，模型输出表明，用产品A密封后，在20年的建模时间内未达到渐近状态，预计85%的全氟辛烷磺酸已淋溶（约340毫克/平方米）。观察到用产品B密封后全氟辛烷磺酸的淋溶可忽略不计（<5×10毫克/平方米）。模拟降雨情景的结果表明，与未密封的受AFFF影响的混凝土表面相比，密封表面的PFAS淋溶性降低。
