Perfluoroalkyl substances in soils around the Nepali Koshi River: levels, distribution, and mass balance

Abstract

Perfluoroalkyl substances (PFASs) were analyzed in surface soils along the Koshi River in Nepal, a typical agricultural country with little industrialization and urbanization. Sixteen target PFASs were quantified in soils from a hilly region in central and eastern Nepal, but only ten PFASs were detected. Concentrations of total PFASs ranged from nd (below the detection limit) to 1.78 ng/g dw. The predominant PFASs in soils were perfluoro-octanoic acid (PFOA) and perfluoro-butanesulfonate (PFBS) with concentrations that ranged from nd to 0.26 ng/g dw and nd to 0.38 ng/g dw, respectively. Results of mass balance analysis also revealed weak associations among concentrations of PFASs, extractable organic fluorine (EOF), and total fluorine (TF). PFASs were relatively evenly distributed among locations. Due to the absence of direct emission of PFASs and slow development of local industry, PFASs in soils originated mostly from longrange atmospheric transport, consumer use, and disposal of PFASs-containing products. Uncontrolled disposal of domestic waste will be a challenge to controlling concentrations of PFASs in Nepal.

Perfluorinated Compounds in Greenhouse and Open Agricultural Producing Areas of Three Provinces of China: Levels, Sources and Risk Assessment

“…The concentration of ∑PFAAs in soils around the Koshi River in Nepal ranged from ND (below the detection limit) to 1.78 ng·g −1 ·dw, showing a slightly lower concentration compared to those in China [26]. PFOS and PFOA concentration in soils at former aqueous forming foams training sites ranged from 2.18 to 8520 ng·g −1 ·dw and <0.12–287 ng·g −1 ·dw at military airports Stockholm, Sweden [27].…”

Fluorine Mass Balance and Suspect Screening in Marine Mammals from the Northern Hemisphere

“…2 However, since only a small fraction (<20) of these substances are routinely monitored, PFAS exposure may be underestimated. Indeed, the large quantities of unidentified extractable organofluorine (EOF) in environmental samples (56-100%), [26][27][28][29] cosmetics (68-100%), 30 aqueous film forming foam (AFFF; ~50%), 31 human blood (15-67%), 32 and wildlife (68-90%) 33,34 are cause for considerable concern. Moreover, recent investigations using non-target and suspect-screening analytical workflows have uncovered an unprecedented number of novel PFAS structures, some of which may account for this unidentified organofluorine.…”

Investigation of per- and polyfluoroalkyl substances (PFAS) in soils and sewage sludges by fluorine K-edge XANES spectroscopy and combustion ion chromatography

“…Whereas several studies considering PFAS sum parameter analysis of contaminated soils were performed during the last decade (Wang et al 2013;Codling et al 2014;Tan et al 2014;Lange et al 2017), less attention was paid to PFAS sum parameter analysis of polluted sewage sludges (Yeung and Eriksson 2017;Aro et al 2021). To determine the sum parameter EOF, all soil and sewage sludge samples (soil1-4, SL1-6) were extracted according to the modified process.…”

“…Since the number of PFAS alternatives is also relative to advancing progress of the regulatory enforcement, different future analytical approaches are inevitable. First reported by Miyake et al in 2007(Miyake et al 2007, fluorine sum parameters like adsorbable organic fluorine (AOF), extractable organic fluorine (EOF), and total fluorine (TF) can be applied to survey and detect the presence of large amounts of unidentified organofluorine compounds in environmental matrices like water sources (Wagner et al 2013;Willach et al 2016;von Abercron et al 2019;Gehrenkemper et al 2021), biota (Koch et al 2019;Spaan et al 2020;Wang et al 2020), or soils (Wang et al 2013;Yeung et al 2013;Tan et al 2014), yielding a much more comprehensive image. More than a decade later, fluorine sum parameters have been established as a useful supplement to classic target analytical approaches of PFAS (Nakayama et al 2019) and were implemented for the first time as a sum value "PFAS-total" in the recently revised Drinking Water Directive (2020/2184) by the European Commission.…”