Effects of biofouling on the uptake of perfluorinated alkyl acids by organic-diffusive gradients in thin films passive samplers. Issue 2 (11th January 2022)

• Record Type: Journal Article
• Authors: Wang, Po; Challis, Jonathan K.; He, Zi-Xuan; Wong, Charles S.; Zeng, Eddy Y.
• Is Part Of: Environmental science. Volume 24:Issue 2(2022)
• Page Start: 242
• Page End: 251
• Publication Date: 2022-01-11
• Subjects: Environmental monitoring -- Periodicals; Biological monitoring -- Periodicals; Environmental chemistry -- Periodicals; 363.7363
• DOI: 10.1039/d1em00436k
• Languages: English
• ISSNs: 2050-7887

Abstract

Abstract : Biofouling did not significantly influence o-DGT performance for common PFAS during long-term deployment under flowing conditions, but the additional diffusive distance through biofilms may need correction under static conditions. Abstract : While organic-diffusive gradients in thin films (o-DGT) passive samplers have been used to assess organic contaminants in water, the effects of biofouling on accurate analyte quantification by o-DGT are poorly understood. We evaluated the effects of biofouling on the uptake of six common perfluoroalkyl substances (PFAS) using a previously developed polyacrylamide-WAX (weak anion exchange) o-DGT without a filter membrane. Linear uptake ( R 2 > 0.91) over 21 days was observed in fouled samplers. The measured sampling rates ( R s ) and accumulated masses of PFAS in pre-fouled o-DGT were significantly lower ( p < 0.05, 20–39% relative error) than in control-fouled samplers. However, compared to clean o-DGT (no biofouling), the R s of most PFAS in control-fouled samplers ( i.e., those with clean diffusive and binding gels initially) were not affected by biofouling. Under flowing (∼5.8 cm s −1 ) and static conditions, the measured diffusive boundary layer (DBL) thicknesses for clean o-DGT were 0.016 and 0.082 cm, respectively, whereas the effective in situ biofilm thicknesses for fouled o-DGT were 0.018 and 0.14 cm, respectively. These results suggest that biofilm growth does not have significant effects on target PFAS sampling by o-DGT under typical flowing conditions (≥2 cm s −1 ). However, rapid surface growth of biofilm on o-DGT deployed in quiescent waters over long periods of time may exacerbate the adverse effects of biofilms, necessitating the estimation of biofilm thickness in situ . This study provides new insights for evaluating the capability of o-DGT samplers when biofilm growth can be significant.