Investigating sources and pathways of perfluoroalkyl acids (PFAAs) in aquifers in Tokyo using multiple tracers

Abstract

We employed a multi-tracer approach to investigate sources and pathways of perfluoroalkyl acids (PFAAs) in urban groundwater, based on 53 groundwater samples taken from confined aquifers and unconfined aquifers in Tokyo. While the median concentrations of groundwater PFAAs were several ng/L, the maximum concentrations of perfluorooctane sulfonate (PFOS, 990 ng/L), perfluorooctanoate (PFOA, 1800 ng/L) and perfluorononanoate (PFNA, 620 ng/L) in groundwater were several times higher than those of wastewater and street runoff reported in the literature. PFAAs were more frequently detected than sewage tracers (carbamazepine and crotamiton), presumably owing to the higher persistence of PFAAs, the multiple sources of PFAAs beyond sewage (e.g., surface runoff, point sources) and the formation of PFAAs from their precursors. Use of multiple methods of source apportionment including principal component analysis-multiple linear regression (PCA-MLR) and perfluoroalkyl carboxylic acid ratio analysis highlighted sewage and point sources as the primary sources of PFAAs in the most severely polluted groundwater samples, with street runoff being a minor source (44.6% sewage, 45.7% point sources and 9.7% street runoff, by PCA-MLR). Tritium analysis indicated that, while young groundwater (recharged during or after the 1970s, when PFAAs were already in commercial use) in shallow aquifers (<50 m depth) was naturally highly vulnerable to PFAA pollution, PFAAs were also found in old groundwater (recharged before the 1950s, when PFAAs were not in use) in deep aquifers (50-500 m depth). This study demonstrated the utility of multiple uses of tracers (pharmaceuticals and personal care products; PPCPs, tritium) and source apportionment methods in investigating sources and pathways of PFAAs in multiple aquifer systems.

Pepper mild mottle virus as an indicator and a tracer of fecal pollution in water environments: Comparative evaluation with wastewater-tracer pharmaceuticals in Hanoi, Vietnam

“…In groundwater, broadly used, hydrophilic and highly persistent compounds, such as artificial sweeteners, have been suggested as powerful wastewater tracers (Buerge et al, 2009;Tran et al, 2014a;Van Stempvoort et al, 2011). A multi-tracer approach and statistical methods are also useful in evaluating contamination of groundwater (Gasser et al, 2014;Kuroda et al, 2014;Van Stempvoort et al, 2013).…”

Remediation of PFAS-Contaminated Soil and Granular Activated Carbon by Smoldering Combustion

“…Per- and polyfluoroalkyl substances (PFASs) have been extensively used in commercial, industrial, and military applications since the 1950s . The strong carbon–fluorine bonds make PFAS resistant to thermal, chemical, and biological degradation. − As a result, PFAS are a widespread source of contamination to groundwater, surface water, drinking water, and soil. − The adoption of increasingly stringent regulatory limits has spurred interest in developing remediation options for both contaminated water and soils …”

Applicability of the direct injection liquid chromatographic tandem mass spectrometric analytical approach to the sub-ng L−1 determination of perfluoro-alkyl acids in waste, surface, ground and drinking water samples

“…PFAAs are characterized by high resistance to physical, chemical and biological degradation and have been widely employed since the 1950s in a wide range of industrial and commercial applications, as well as in fluoropolymer production, giving rise to a widespread contamination of environmental matrices. More in detail, PFAAs have been determined in wastewater [1][2][3], surface water [4][5][6] and drinking water [7]. Moreover, PFAAs have been detected in remote areas like open oceans [8] and Arctic [9,10].…”