Uptake and translocation of perfluoroalkyl acids by hydroponically grown lettuce and spinach exposed to spiked solution and treated wastewaters

Perfluoroalkylated adds (PFAAs) are ubiquitous xenobiotic substances characterized by high persistence, bioaccumulation potential and toxicity, which have attracted global attention due to their widespread presence in both water and biota. In this study, the main objective was to assess PFAAs uptake and accumulation in lettuce (Lactuca sativa L) and spinach (Spinacia oferacea L.) when fed with reclaimed wastewaters that are usually discharged onto a surface water body. Lettuce and spinach were grown in hydroponic solutions, exposed to two different municipal wastewater treatment plant (WWTP) effluents and compared with a spiked-PFAAs aqueous solution (nominal concentration of 500 ng L-1 for each perfluoroalkyl acid). Eleven perfluoroalkyl carboxylic adds and three perfluoroalkyl sulfonic adds were determined in the hydroponic solution, as well as quantified at the end of the growing cycle in crop roots and shoots. Water and dry plant biomass extracts were analyzed by liquid chromatography-electrospray ionization tandem spectrometry LC-MS/MS technique. The bioconcentration factor of roots (RCF), shoots (LCF), and the root-shoot translocation factor (IF) were quantified. In general, results showed that PFAAs in crop tissues increased at increasing PFAAs water values. Moreover some PFAAs concentrations (espedaily PFBA, PF135, PFHxA, PFHpA. PFHxS) were different in both shoots and roots of lettuce and spinach, regardless of the type of water. The long C-chain PFAAs (>= 9) were always below the detection threshold in WWTPs effluents. However, when PFAAs were detected, similar bioconcentration parameters were found between crops regardless the type of water. A sigmoidal RCF pattern was found as the perfluorinated chain length increased, plus a linear IF decrease. Comparing bioconcentration factor results with findings of previous studies, lettuce RCF value of PFCAs with perfluorinated chain length <= 9 and PFSAS was up to 10 times greater. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that the levels of PFAAs in crop tissues increased with increasing PFAAs water values. Additionally, certain PFAAs concentrations differed in the shoots and roots of lettuce and spinach, regardless of the type of water. Long chain PFAAs (>= 9) were consistently below detection thresholds in WWTP effluents.