Perfluorooctanoate (PFO) in Forest Soils near a Fluoropolymer Manufacturing Facility

Hangen, Edzard; Klemm, Andreas; Kronawitter, Helmut; Schubert, Alfred

Perfluorooctanoate (PFO) in Forest Soils near a Fluoropolymer Manufacturing Facility

2010

Hangen, Edzard | Klemm, Andreas | Kronawitter, Helmut | Schubert, Alfred

After elevated concentrations of perfluorooctanoate (PFO) were found in river and groundwater in the vicinity of a fluoropolymer manufacturing facility, numerous soils at adjacent sites were sampled in 2007. Within a 5-km northeast-oriented sector around a probable point source, 20 forest sites were investigated and compared to deposition and groundwater data. PFO concentrations up to 600 µg/kg were detected in the soils, and PFO concentrations typically decreased toward deeper soil depths. In mixed or deciduous forests, maximum concentrations of PFO occurred in the topsoil, pointing to the favorable decomposition and incorporation of deciduous litter. PFO concentrations of the organic layer over the 20 sampling sites were interpolated using ordinary kriging. Highest PFO content in the organic layer was located about 500 m away from the point source in the regional wind direction, decreasing asymptotically outwards. Long-term monitoring data pointed to an accumulation of PFO over time in the organic layer. The data suggest that PFO might be released in the course of litter decomposition and transported toward deeper soil regions only gradually. The soils' PFO concentrations reflect the deposition data. The transport link toward groundwater is currently established in lysimeter studies.

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