Co-occurrence and correlations of PFASs and chlorinated volatile organic compounds (cVOCs) in subsurface in a fluorochemical industrial park: Laboratory and field investigations

Xiaoyan Ding; Xin Song; Minmin Xu; Jin Yao; Chang Xu; Zhiwen Tang; Zhuanxia Zhang

doi:10.1016/j.scitotenv.2021.152814

Co-occurrence and correlations of PFASs and chlorinated volatile organic compounds (cVOCs) in subsurface in a fluorochemical industrial park: Laboratory and field investigations

Sci Total Environ. 2022 Mar 25:814:152814. doi: 10.1016/j.scitotenv.2021.152814. Epub 2022 Jan 3.

Authors

Xiaoyan Ding¹, Xin Song², Minmin Xu³, Jin Yao⁴, Chang Xu⁵, Zhiwen Tang¹, Zhuanxia Zhang¹

Affiliations

¹ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: xsong@issas.ac.cn.
³ Shandong Academy of Environmental Sciences Co., Ltd., Jinan 250013, China.
⁴ Zhongke Hualu Soil Remediation Engineering Co., Ltd., Dezhou 253500, China.
⁵ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Sichuan Tianshengyuan Environmental Services Co., Ltd., Chengdu 610000, China.

PMID: 34990671
DOI: 10.1016/j.scitotenv.2021.152814

Abstract

Fluorochemical industrial park (FIP) represents an important source of per- and polyfluoroalkyl substances (PFASs) and chlorinated volatile organic compounds (cVOCs). Exploring the co-occurrence and correlations of PFASs and cVOCs is a key step towards the understanding their distributions in the field. In this study, perfluorooctanoic acid (PFOA) was the dominant compound in groundwater and aquifer solids, and elevated concentrations of short-chain perfluoroalkyl carboxylic acids (PFCAs) and hexafluoropropylene oxide oligomers were also detected in the field, suggesting their wide applications as substitutes for PFOA. Correlation analyses between PFASs and cVOCs suggested that cVOCs had a significant influence on the distribution and composition of PFASs in the field. In addition, the presence of cVOCs in the form of dense non-aqueous-phase organic liquids (DNAPL) affected the distribution and migration of PFASs at various depths, as evidenced by the relatively high PFASs concentrations (204 μg/L) and PFOA abundance (85.4%) in the deep aquifer, likely due to DNAPL-water interfaces sorption or partition into bulk DNAPL. The log K_d values, determined in the laboratory, were found to increase in the presence of DNAPL, especially for PFOA, with more than one time higher than those of perfluorobutanoic acid (PFBA) and hexafluoropropylene oxide dimer acid (HFPO-DA). This conclusion further demonstrated that PFOA had a higher potential to participate into DNAPL, which can migrate with DNAPL to the deep aquifer, supporting the higher abundance of PFOA in the deep aquifer mentioned above. However, the log K_d-field values of PFBA and HFPO-DA in the field were higher than that of PFOA, and no significant correlations (p > 0.05) were found between log K_d-field values and the chain-length of PFCAs at various depths, suggesting that the phenomena observed in the field are a result of composite influencing factors.

Keywords: DNAPL; Distribution coefficients; Fluorochemical industrial park; Groundwater; HFPO-TA; PFASs.

MeSH terms

China
Environmental Monitoring
Fluorocarbons* / analysis
Laboratories
Volatile Organic Compounds*
Water Pollutants, Chemical* / analysis

Substances

Fluorocarbons
Volatile Organic Compounds
Water Pollutants, Chemical