A Pilot Study of the Fluorinated Ingredient of Scotchgard Products and Their Levels in WWTP Sludge and Landfill Leachate from Sweden

By Felicia Fredriksson, Ulrika Eriksson, Anna Kärrman, and Leo Yeung
March 16, 2020

This study performed by Örebro University on behalf of the Swedish Environmental Agency aims at assessing the occurrence and levels of the newly identified side-chain fluorinated polymers from an environmental perspective. The aims of present study are 1) to develop instrumental and extraction methods to measure the active ingredient of two Scotchgard products (two side-chain fluorinated polymers, hereafter referred to as Pre-2002 and Post-2002) in sludge and leachate samples from Swedish wastewater treatment plants and landfills; 2) to evaluate if Pre-2002 and Post-2002 may be responsible for the unidentified organofluorine in the sludge samples from our previous screening study reporting extractable organofluorine (EOF); and 3) to conduct a mass balance analysis on EOF and sum of 93 per- and polyfluoroalkyl substances (PFAS) including Pre-2002 and Post-2002 in the sludge and landfill leachate samples to assess the levels of unidentified EOF that potentially are other polymeric or non-polymeric PFAS.

Levels of Pre-2002 and Post-2002 and EOF are reported for sludge samples from four wastewater treatment plants (Bergkvara in Torsås, Gässlösa in Borås, Henriksdal in Stockholm, and Öhn in Umeå) collected in 2015, and leachate samples from three different landfills (Atleverket in Örebro, Hässleholm Kretsloppscenter in Hässleholm, and Flishult in Vetlanda). Sludge samples from Gässlösa wastewater treatment plant collected between 2004 and 2016 (excluding 2005 and 2006) were analyzed to assess any temporal trends of the two side-chain fluorinated polymers (Pre-2002 and Post-2002). The present investigation reported levels of both Pre-2002 and Post-2002 in all sludge samples (158-2618 ng/g d.w.). Levels of Pre-2002 were always higher than those of Post-2002 in the same samples. A declining trend was observed for Pre-2002 in sludge samples from Gässlösa but no clear trend was noted for Post-2002. The concentrations of the Pre-2002 and Post-2002 in sludge were higher than the sum of 83 PFAS analyzed in the previous screening study. No relationship between number of people that the wastewater treatment plants served and the concentrations of EOF and Pre-2002 and Post-2002 could be observed. The concentrations of both EOF and Pre-2002 and Post-2002 seem to be more related to the types of industry located in that area. Only three of the five leachate samples showed detectable levels of Pre-2002. Post-2002 was not detected in any of the landfill leachates. The low levels could be due to that both compounds are strongly sorbed to particles, which indicates the fate and distribution of these compounds. For both the sludge and leachate samples, the quantified levels of Pre-2002 and Post-2002 only contributed to a minor part of the EOF. A high proportion of unknown EOF still remains and may be related to other polymeric or non-polar PFAS.

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