Combining Freshwater Irrigation with Vegetable Selection to Mitigate the Occurrence of Per- and Polyfluoroalkyl Substances in Edible Vegetable Parts in a Semiarid Farmland in Northwestern China

Abstract

Reclaimed-water irrigation can introduce perfluoroalkyl and polyfluoroalkyl substances (PFASs) into farmlands. Selecting an appropriate irrigation method may mitigate the adverse effects of reclaimed-water irrigation; however, the effects of irrigation methods on PFAS pollution in different vegetables have remained poorly studied. Here, we collected soils from a farmland irrigated with long-term reclaimed-water irrigation to cultivate potato, carrot, cabbage, and pak choi using surface and sprinkler irrigation with reclaimed water or freshwater; the concentrations in water, soil, and vegetable samples, bioconcentration and translocation factors, and estimated daily intake of PFASs were quantified. Transitioning from reclaimed water to freshwater did not significantly alter soil PFAS concentrations but generally reduced PFAS concentrations in vegetables. Carrot and potato had lower PFAS concentrations in edible parts and estimated daily intake of PFASs than cabbage and pak choi, suggesting lower health risks for residents consuming carrot and potato. The bioconcentrations of individual perfluoroalkyl carboxylic acids in the edible parts increased with shorter carbon-chain lengths, and cabbage and pak choi accumulated more short-chain PFASs in the edible parts than carrot and potato. This study highlights that implementing procedures to ensure cleaner irrigation water when growing nonleafy vegetables can effectively mitigate PFAS pollution in farmlands.