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 Rastatt/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, Germany, 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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