Leaching of Per- and Polyfluoroalkyl Substances (PFAS) from Agricultural Soils to Groundwater Peter Grathwohl, Klaus Röhler, Alexander Haluska, Mike Annable, Jaehun Cho, Bernd Susset Case study • In Baden-Wuerttemberg approx. 600 Ha of agricultural fields contaminated with PFAS (paper sludge)

Contaminated land

GW protection zones

Conc. [µg/l]

2 PFAS - Precursors • Per- and polyfluorinated alkyl substances (PFAS) comprise >3000 individual compounds Precursors

Mono-PAPs

FTOH Precursors forming stable end- Di-PAPs products e.g. Perfluorinated carbonic acids (PFCAs) and Perflurionated sulfonic acids Di-SAmPAPs (PFSAs)

Wang et al. 2009 Chemosphere 75 1089–1096

3 Properties

- HA pKa ≤ 0.4 A (Goss, 2008)

C3 C4 C5 C6 C7 C8 C8 C9 C10 1 Analyt F(CF2)n-Unit 0,9 F(CF PFBA 3 0,8 2 ) n PFPeA 4 Env. relevant 0,7

Anion PFHxA 5

of 0,6 PFHpA 6 0,5 PFOA 7 Modified from Kraft and Riess, 2015 Fraction 0,4 PFNA 8

0,3 PFDA 9

0,2 PFUnA 10 0 1 2 3 4 5 6 7 8 9 10 11 12

pH 4 Properties 1000 100 PFCAs max. Kd 100 10

10 [l/kg]

d Kd field samples K 1 CMC [g/l] 1

min. Kd 0,1 0 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 10 Fluorinated chain length Fluorinated chain length Literatur Min Literatur Max Own Data Reth et al. 2011 (selected literature data)

Kd data collected from: Guelfo & Higgins, 2013, Bräuning et al., 2019, Li et al., 2019, Pereira et al., 2018, Enevoldsen & Juhler 2010, Milinovic et al., 2015, Campbell et al., 2009, Field: Arcadis

5 Determination of priority PFAS /Baden-Baden

562 soil samples including leaching tests

Priority list of relevant compounds

Priorität absteigend Nummer im UM Erlass Einzelsubstanz GFS Perzentilwert Einhaltung [µgl-1] GFS [%]

1 2 PFOA 0,3 30 2 5 PFDeA 0,3 55 2 4 PFNoA 0,3 55 3 7 PFHpA 0,3 65 4 1 PFOS 0,23 70 ? 10 PFPeS 1,0 - 9 PFHxA 1,0 92 6 PFHpS 0,3 94 11 PFPeA 3,0 98 nicht 3 H4PFOS 0,3 100 bewertungsrelevant 8 PFHxS 0,3 100 12 PFBS 3,0 100 13 PFBA 7,0 100 Weitere per- und polyfluorierte Substanzen aus der Datenbank der Arcadis GmbH

- H2PFDA 1,0 100

- H4PFUNA 1,0 100 - HPFHPA 1,0 100 nicht - PFDS 1,0 100 bewertungsrelevant - PFDDS 1,0 98 - PFUDS 1,0 100 6 - PFOSA 1,0 99 PFC-Quellterm Rastatt/Baden-Baden

Vertical Mobility? PFO/NoA conc. increase with depth

7 First Incident – NRW, , 2006

10 ha contaminated – collection of seepage water

8 Long Term Monitoring Seepage Water C ° . Temp . µg/l / Conc

Okt.09 Dez.11 Dez.12 Dez.13

9 Column Tests & Modelling 1 ) 1 − 45 − !" : 45 + !" +;<= $ ∗ & ∗ ( + = +0 ∗ 1 − 0.5 ∗ 123+ + 1)9 123+ 1 − !" = ' 7 & 7 7 & +> ) ∗ * 2 ) !" * + 45 2 ) !" * + 45 (Grathwohl & Susset, 2009)

PFOAPFOS KdKd == 0.20.8 l/kgl/kg

310310 daysdays

10 Conclusions

• PFOA and PFOS priority pollutants on agricultural land

• Column tests suitable for assessment of PFC leaching from soils

• Production rates from precursors seasonally variable

• Sorption in subsoils very low (Kd << 1) è high mobility in groundwater

• Time scales for field scale leaching up to centuries

è Future Work

• Determination of sorption and leaching behavior

• Measurement of mass fluxes in field (passive flux meters) 11 Thank you! Funding: State Environmental Ministry (SiWaPFC, BW PFC 19001)

Contact: Prof. Peter Grathwohl University of Tübingen · Germany [email protected]

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