The occurrence, spatial distribution, and well-depth dependence of PFASs in groundwater from a reclaimed water irrigation area

Jiao Xingchun; Zhao Wei; Pan Jing; Lu Guohui; Chen Dian; Zhang Zhaohe; Zhao Yiran

doi:10.1016/j.scitotenv.2023.165904

The occurrence, spatial distribution, and well-depth dependence of PFASs in groundwater from a reclaimed water irrigation area

Sci Total Environ. 2023 Nov 25:901:165904. doi: 10.1016/j.scitotenv.2023.165904. Epub 2023 Jul 30.

Authors

Jiao Xingchun¹, Zhao Wei², Pan Jing³, Lu Guohui⁴, Chen Dian⁵, Zhang Zhaohe⁵, Zhao Yiran⁴

Affiliations

¹ National Research Center for Geoanalysis, Chinese Academy of Geological Sciences, China. Electronic address: jiaoxingchun@cags.ac.cn.
² Beijing Institute of Geological Environment Monitoring, China.
³ Chinese Academy of Geological Sciences, China.
⁴ National Research Center for Geoanalysis, Chinese Academy of Geological Sciences, China.
⁵ School of Earth Sciences and Resources, China University of Geosciences Beijing, China.

PMID: 37527708
DOI: 10.1016/j.scitotenv.2023.165904

Abstract

With the growing development of modern agriculture and industry, groundwater is facing more and more complex contaminants. One such contaminant is per- and polyfluoroalkyl substances (PFASs), which pose a potential risk to human health, particularly for those who rely on groundwater as their primary source of drinking water. In this study, we conducted a comprehensive investigation on the occurrence, spatial distribution, and source apportionment of PFASs in shallow (<60 m) and deep (>80 m) groundwater samples from a reclaimed water irrigation area in Beijing's suburbs. Our results showed that the average total PFAS concentration (∑10PFAS) for all samples was 10.55 ± 7.77 ng/L, ranging from 1.05 to 34.28 ng/L. The dominant congeners were PFBA, PFOA, and PFBS. No significant linear relationship was observed between PFAS concentrations and the well depth. However, the averaged ΣPFASs in groundwater were highest in the uppermost layer and declined sharply to a few ng/L in the deep aquifer below 80 m. PFASs showed elevated concentration in shallow aquifers in 9 out of 11 paired wells, indicating an overall descending trend of PFASs with increasing aquifer depth. The spatial distribution of PFASs was highly heterogeneous and showed different patterns in shallow and deep groundwater, which may be related to the complicated attenuation behavior of PFAS compounds when they transport and diffuse through overlapping aquifer layers. The influence of the landfill on groundwater PFASs was most pronounced within a 5 km radius. Source apportionment results indicated that reclaimed water irrigation is the main non-point source of PFASs in shallow groundwater. In contrast, deep groundwater is primarily subject to point sources and lateral recharge flow. This investigation of PFASs in shallow and deep wells provides a foundation for further exploration of PFASs transportation and risk prevention in regions where groundwater is a major water resource for domestic and industrial development.

Keywords: Groundwater; Landfill; Per- and polyfluoroalkyl substances (PFASs); Reclaimed water irrigation; Well depth.