title: Getting on with persistent pollutants: Decreasing trends of perfluoroalkyl acids (PFAAs) in sewage sludge.
abstract: Sewage sludge can be a relevant source of perfluoroalkyl acids (PFAAs) for the environment. In order to reduce emissions from this source, Bavarian authorities enforced in 2008 an analysis of PFAAs from sewage sludge derived from municipal wastewater treatment plants (WWTPs). 4981 sludge samples from 1165 different WWTPs were analyzed between 2008 and 2013 for 11 PFAAs compounds. During this period, 71 WWTPs exceeded the precautionary limit of 125 μg kg(-1) dm of total PFAAs in sludge samples at least once with a decreasing tendency. The yearly exceedances of the investigated WWTPs decreased from 6% in 2008 to 0.8% in 2013. At the same time, the percentage of uncontaminated WWTPs increased from 33% to 65%. Perfluorooctane sulfonic acid (PFOS) was the predominant compound found in 41% of all sludge samples. Perfluorodecanoic acid (PFDA) was detected in 19% and Perfluorooctanoic acid (PFOA) in 7%. Very high PFAAs concentrations (>500 μg kg(-1) dm) in sewage sludge were generally caused by firefighting foams containing PFAAs or emissions from PFAAs-using industries including metal plating, textile, leather or paper industries. Trend analyses of the six year period show that PFAAs contamination in sewage sludge clearly decreased for 47% of the WWTPs. However, for 16% of the WWTPs an increasing trend was detected, even though the concentration levels were below the precautionary limit. During the six years of investigation the load of total PFAAs in sewage sludge was reduced by more than 90%, from 17 t a(-1) in 2008 to 1.5 t a(-1) in 2013.
authors.affiliation: Bavarian Environment Agency, Demollstraße 31, D-82407 Wielenbach, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Ulrich
authors.affiliation: Bavarian Environment Agency, Bürgermeister-Ulrich-Straße 160, D-86179 Augsburg, Germany; Research Unit Sustainability and Global Change, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Grindelberg 5, D- 20144 Hamburg, Germany. Electronic address: korbinian.freier@lfu.bayern.de.
authors.forename: Korbinian P
authors.initials: KP
authors.lastname: Freier
authors.affiliation: Bavarian Environment Agency, Demollstraße 31, D-82407 Wielenbach, Germany; Bavarian Environment Agency, Bürgermeister-Ulrich-Straße 160, D-86179 Augsburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Gierig
mesh_terms: D017738:Alkanesulfonic Acids / Q000032:analysis; D002210:Caprylates / Q000032:analysis*; D003652:Decanoic Acids / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005466:Fluorocarbons / Q000032:analysis*; D012722:Sewage / Q000032:analysis / Q000737:chemistry*; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods; D060753:Water Quality
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D003652:Decanoic Acids; D005466:Fluorocarbons; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical; C036567:perfluorodecanoic acid; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid
keywords: Biosolids; Perfluoroalkyl acids; Perfluorooctane sulfonic acid; Sewage sludge; Trend; Wastewater treatment plant