Identification, occurrence, concentration and composition profile of fiproles in municipal wastewater treatment plants

• Published in: The Science of the total environment 2023-08, Vol.888, p.164198-164198, Article 164198
• Main Authors: Zhang, Qing, Yang, Yingying, Xiao, Yu, Xia, Tian, Shang, Nanxiu, Liu, Yanna, Guo, Feng, Sanganyado, Edmond, Jiang, Xiaoman, Xia, Xinghui
• Format: Article
• Language: English
• Subjects: Chlorinated byproducts; Fipronil; High-resolution mass spectrometry; Suspect screening analysis; Transformation products
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.164198

Although fipronil and several of its transformation products are ubiquitous in aquatic environments, limited information is available on the structural identities, detection frequencies, concentrations and composition profiles of fiproles (fipronil and its known and unknown transformation products) in municipal wastewater treatment plants (WWTPs). In this study, a suspect screening analysis was applied to identify and characterize fipronil transformation products in 16 municipal WWTPs from three cities in China. In addition to fipronil and its four transformation products (fipronil amide, fipronil sulfide, fipronil sulfone and desulfinyl fipronil), fipronil chloramine and fipronil sulfone chloramine were detected for the first time in municipal wastewater. Moreover, the cumulative concentrations of six transformation products were 0.236 ng/L and 3.44 ng/L in wastewater influents and effluents, and accounted for one-third (in influents) to half (in effluents) of fiproles. Of those transformation products, two chlorinated byproducts (fipronil chloramine and fipronil sulfone chloramine) were major transformation products in both municipal wastewater influents and effluents. Notably, the log Kow and bioconcentration factor (evaluated by EPI Suite software) of fipronil chloramine (log Kow = 6.64, and BCF = 11,200 L/kg wet-wt) and fipronil sulfone chloramine (log Kow = 4.42, and BCF = 382.9 L/kg wet-wt) were greater than that of their parent compound. Considering the persistence, bioaccumulation potential and toxicity, the high detection rates of fipronil chloramine and fipronil sulfone chloramine in urban aquatic systems need to be specifically considered in future ecological risk assessments. [Display omitted] •Fipronil chloramine and its sulfone chloramine are identified in municipal WWTPs.•Chlorinated byproducts are major transformation products in municipal wastewater.•Two chlorinated byproducts have high persistence and bioaccumulation potential.•Chlorinated byproducts of fipronil need to be included in environmental monitoring.