A systematic investigation of single solute, binary and ternary PFAS transport in water-saturated soil using batch and 1-dimensional column studies: Focus on mixture effects

被引：9

作者：

Umeh, Anthony C. ^{[1
,2
]}

Naidu, Ravi ^{[1
,2
]}

Olisa, Emmanuel ^{[1
,3
]}

Liu, Yanju ^{[1
,2
]}

Qi, Fangjie ^{[1
,4
]}

Bekele, Dawit ^{[1
,5
]}

机构：

[1] Univ Newcastle, Global Ctr Environm Remediat GCER, Callaghan, NSW 2308, Australia

[2] Univ Newcastle, crcCARE, Callaghan, NSW 2308, Australia

[3] Geosyntec Consultants, 211 Wheeler St, Saskatoon, SK S7P 0A4, Canada

[4] Chinese Acad Sci, Nanjing Inst Soil Sci, 71 Beijing East Rd, Nanjing 210008, Jiangsu, Peoples R China

[5] Douglas Partners Pty Ltd, 439 Montague Rd West End, West End, Qld 4101, Australia

来源：

JOURNAL OF HAZARDOUS MATERIALS | 2024年 / 461卷

关键词：

Mixture Effects; Miscible Displacement Studies; Models; Hydrus-1D; Batch Sorption Isotherm and Desorption; Equilibrium and Nonequilibrium Transport; PERFLUOROALKYL SUBSTANCES; PERFLUORINATED COMPOUNDS; PERFLUOROOCTANOIC ACID; SORPTION; GROUNDWATER; PFOS; MECHANISMS; ADSORPTION; SURFACTANT; DESORPTION;

D O I：

10.1016/j.jhazmat.2023.132688

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

This study aimed to investigate the transport and release of per- and polyfluoroalkyl substances (PFAS), as single solutes and binary and ternary mixtures, and associated competitive sorption effects in water-saturated soil. Batch sorption isotherm and desorption, and one-dimensional miscible displacement studies were conducted. For the batch study, the mixtures exhibited extensive sorption isotherm nonlinearity at aqueous concentrations exceeding 20 mu g/L. At and above this threshold, competitive effects significantly decreased PFAS sorption, mostly affecting perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS). Importantly, mixture effects exacerbated isotherm nonlinearity and may increase the leaching of PFAS in subsurface soil and groundwater. Further, up to 100% desorption occurred for single solutes and mixtures, indicating that the studied PFAS were weakly sorbed. For the column study, at influent concentrations (21 - 27 mu g/L, depending on PFAS) near the threshold, PFOA and PFHxS breakthrough curves (BTC) generally exhibited equilibrium (nonlinear) transport, whereas perfluorooctane sulfonate (PFOS) exhibited nonequilibrium transport, with minimal or no mixture effects. Nonequilibrium transport of PFOS was driven by rate-limited sorption, especially as flow interruption tests confirmed the absence of physical nonequilibrium. The sorption distribution coefficients (Kd) from moment and frontal analyses, and 2-site modelling of the BTC, were consistent with the batch-derived Kd, although comparatively smaller. Such discrepancies may limit the applicability of batch-derived Kd values for predictive transport modelling purposes. Overall, understanding mixture impacts may aid effective predictive modelling of PFAS transport and leaching, especially in aqueous film forming foam (AFFF)-source zone areas associated with elevated PFAS concentrations. At low or environmental PFAS concentrations, mixture effects can be expected to be play a minor role in influencing PFAS transport.

引用

页数：15