Concentrations and Distribution Patterns of Perfluoroalkyl Acids in

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Agricultural and Environmental Chemistry

Concentrations and Distribution Patterns of Perfluoroalkyl Acids (PFAA) in Sewage Sludge and in Biowaste in Hesse, Germany Thorsten Stahl, Matthias Gaßmann, Sandy Falk, and Hubertus Brunn J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b03063 • Publication Date (Web): 07 Sep 2018 Downloaded from http://pubs.acs.org on September 11, 2018

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Journal of Agricultural and Food Chemistry

Concentrations and Distribution Patterns of Perfluoroalkyl Acids (PFAA) in Sewage Sludge and in Biowaste in Hesse, Germany Thorsten Stahl†*, Matthias Gassmann§, Sandy Falk‡, Hubertus BrunnII †

Hessian State Laboratory, Am Versuchsfeld 11-13, 34128 Kassel, Germany Department of Water Quality Management - Modelling and Simulation, University of Kassel, Kurt-Wolters-Str. 3, 34125 Kassel,Germany ‡ Hessian State Laboratory, Glarusstr. 6, 65203 Wiesbaden, Germany II Hessian State Laboratory, Schubertstr. 60, 35392 Giessen, Germany §

*To whom correspondence should be addressed. Tel: +49 561 9888239 Fax: +49 561 9888300 E-mail: [email protected]

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ABSTRACT A total of 201 sewage sludge and 45 biowaste samples were examined for 14 different perfluoroalkyl acids (PFAA). For perfluorooctanesulfonic acid, maximum concentrations of 698 µg/kg dry weight were measured in sewage sludge and for perfluorohexane sulfonic acid 29.0 µg/kg dry weight were found in biowaste. Looking at the fingerprints of both these matrices it can be see that long-chain PFAA make up 85.9% of the total concentration in sewage sludge whereas short-chain PFAA only account for 14.1%. In contrast, the trend in biowaste is just the opposite, with 53.2% long-chain and 46.8% short-chain PFAA. These results lead to the conclusion that sewage sludge functions as a sink for long-chain PFAA, and the plants preferentially take up short-chain PFAA from the sludge/soil, as seen by the concentrations found in biowaste. It can be calculated that the total yearly amount of PFAA spread onto agricultural lands amount to 15.3 kg.

KEYWORDS PFAA, sewage sludge, biowaste, fertilizer, fingerprints


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INTRODUCTION Perfluoroalkyl Acids (PFAA) are organic compounds in which the hydrogen atoms have been substituted by fluorine atoms, with the exception of the hydrogen atoms that are constituents of functional groups. PFAA have been in use both in industry and in the household for more than 60 years (1). Some representatives of the PFAA family have been shown in animal experiments to be easily taken up orally and accumulate primarily in blood and liver (2). Acute toxicity has been classified as moderate according to the results of animal experiments (2). In animal studies with longer exposure times to perfluorinated compounds diverse toxic effects were observed. Adverse effects up to increased cancer mortality (to the human organism as well) have also been observed in occupational exposure (3). Human PFAA exposure is primarily through dietary uptake including drinking water, and for this reason potential paths of entry and distribution of PFAA in the environment and food chain are of interest. Sewage from industrial processes as well as from agriculture, seepage from landfills, but also sewage from private households are potential paths of entry to the environment. After application of polluted sewage sludge as fertilizer for agricultural lands, rainfall-runoff processes can result in contamination of both surface and ground water (4, 5). Moreover, agricultural crops growing on soil that has been treated with sewage sludge may take up PFAA (carryover) as has been documented in relevant studies (6-9). If such crops are used directly as human food one can speak of a direct path of entry into the human organism. An example of an indirect path would be feeding PFAA contaminated feed to livestock to be used as human nutrition. This entry pathway has been demonstrated in a study by the German Federal Institute for Risk Assessment (BfR) (10, 11) in which PFAA contaminated maize silage was fed to sheep and cattle. Since sewage sludge represents a sink for PFAA (12-14) and within the framework of the German sewage sludge regulation (Klärschlammverordnung) the sludge, as well as biowaste is used as soil fertilizer, the question arises as to the PFAA contamination of sludge and biowaste. In addition, levels in sewage sludge reflect the release of PFAA from consumer products and industrial use and are therefore useful as an indication of the contemporary release of PFAA into the environment, both by households and


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industry (15). The German directive that regulates the use of fertilizers, soil conditioners, culture substrates and plant aids (16) specifies a limit of 100 µg/kg dry weight of the sum of both the socalled marker or lead substances, perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS). Sewage sludge containing higher concentrations than this must be incinerated. The sludge must be identified as such if the sum of PFOA and PFOS exceed 50 µg/kg dry weight (limit of labeling requirement). In Germany, a total of about 1.8 million tons of sewage sludge (dry weight) from municipal sewage treatment plants was produced, of which 427,736 tons (23.7%) were used as agricultural fertilizer and 190,127 tons (10.5%) in landscape construction (17). In the state of Hesse alone a total of 54,229 tons of sewage sludge and 139,939 tons of biowaste (both DW) were spread over agricultural or garden lands in the year 2014 (17). Since both, sewage sludge and biowaste, are potential sources of PFAA in the environment, a total of 201 sewage sludge samples and 45 biowaste samples were analyzed for their PFAA content in the present study. In addition, focus was placed on the question of whether the PFAA patterns were different in the two different matrices and the total amount of PFAA that was introduced into the environment via sewage sludge was estimated.

MATERIALS AND METHODS Standards. The chemical PFAA standards used in our study were perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA) perfluorotetradecanoic acid (PFTeDA), perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS) and perfluorooctanesulfonic acid (PFOS) with chemical purity each ≥ 98%, as well as mass-labeled internal standards PFBA-13C, PFHxA-13C, PFOA-13C, PFNA-13C, PFDA-13C, PFHxS-13C and PFOS-13C (isotopic purity each ≥ 99%). All of the standards were produced by Wellington Laboratories (Ontario, Canada) and were obtained from


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Campro Scientific (Berlin, Germany). All PFAA standards were ordered in 1 mL glass ampules (concentration 50 µg/mL methanol). The solutions were combined (one solution each with spiked and unspiked standards) and methanol added to achieve a final volume of 50 mL, so that the end concentration of each analyte in the PFAA mixture amounted to 100 µg/L. PFAA mixture with concentrations of 10 µg/L and 1 µg/L were prepared by dilution with methanol.

Chemicals. Acetonitrile, methanol and water with a purity of ≥ 99.97% as well as ammonium acetate were obtained from Biosolve BV (Valkenswaard, Netherlands). An in-house preparation of QuEChERS-Mix according to Anastassiades (18) was used for clean up during sample preparation for the analysis of sewage sludge and biowaste. This mix contained sodium citrate tribasic dihydrate with a purity of ≥ 99.5%, magnesium sulfate with a purity of ≥ 97.0% and disodium hydrogen citrate sesquihydrate with a purity of ≥ 99.0% from Sigma-Aldrich Chemie GmbH (Steinheim, Germany) and sodium chloride with a purity of ≥ 99.5% obtained from Merck KGaA (Darmstadt, Germany). Formic acid with a purity of 98% from Sigma-Aldrich Chemie GmbH (Steinheim, Germany) was used in water for conditioning and washing solid phase extraction cartridges for the analysis of sewage sludge and biowaste. Ammonium hydroxide for eluting PFAAs from cartridges was obtained from Sigma-Aldrich Chemie GmbH. Oasis WAX 3 mL, 60 mg, 60 µm cartridges were supplied by Waters GmbH (Eschborn, Germany). All samples were filtered through disposable Chromafil® polyester syringe filters with a pore size of 0.2 µm from Macherey-Nagel (Düren, Germany) before LC-MS/MS analysis.

Sampling of sewage sludge and biowaste. 201 samples of sewage sludge and 45 samples of biowaste were collected from 2010 to 2016. Differentiation was made in regard to sampling of sewage sludge and biowaste between liquid, dry or paste-like samples.


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Sewage sludge samples. Sewage sludge samples were collected from different sewage treatment plants. Liquid sewage sludge samples were characterized by a dry weight (DW) between 3% and 6%, paste-like sewage sludge samples by a dry weight between 18% and 20%. Solid and paste-like samples were dehydrated by use of a belt filter press. Liquid sewage sludge samples were obtained from the sewage plant using a 1 liter polypropylene (PP) container fastened to a wooden pole. A total of 10 to 15 individual samples were combined in a 10 liter metal bucket with a lid to create a mixed sample. Again, 10 individual samples were combined in a 10 liter metal bucket with lid to create a mixed sample. Following transport of the bucket to the preparation laboratory, the contents were homogenized using an electric drill with a metal agitator (mixing paddle). Two-liter aluminum trays were filled with 1.5 L liquid or 1.0 kg solid/paste-like samples.

Biowaste samples. Liquid biowaste samples, e.g. from biogas plants, contained characteristically between 3% and 10% DW, solid biowaste samples about 4% DW. Liquid samples were drawn from the plant through a faucet or a gate valve into a 2 liter PP wide-necked container with screw lid. After transport of the 2 liter sample containers and the bucket to the sample preparation laboratory, the liquid samples were shaken. A two-liter aluminum tray was filled with 1.5 L liquid samples. Solid samples are collected from biowaste aggregate material with a volume (depending upon the size of the biowaste facility) of 300 m3 to 2,000 m3. For smaller masses of aggregate material sampling is performed using a shovel to collect multiple random samples that are placed in a 90L plastic sack. For larger masses of aggregate material a sample of about 2 m3 is removed with a wheel loader and random samples are taken from this mass using a shovel and are placed in 90L plastic sacks analogously to the method used for smaller masses. These samples are then homogenized using a mixer in the laboratory and an aliquot of about 1 kg is placed in aluminum tray for sample preparation.


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Sample preparation of sewage sludge and biowaste. The aluminum trays filled with sewage sludge or biowaste were dried to constant weight in a thermostatically controlled drying oven at 105 °C. All PFAA concentrations are based upon these dry weights. The dried samples were quantitatively transferred using a metal scoop to 250 mL tungsten carbide shaker cups containing balls also made of tungsten carbide. The samples in the shaker cups were ground in a ball mill for 15 minutes at 26.8 G and then passed through a metal sieve with a mesh size of 0.5 mm into a plastic dish. One gram of the dried and homogenized sewage sludge or biowaste was placed into a 15 ml centrifuge tube and was spiked with 50 µl internal standard solution (concentration 100 µg/L per analyte), 2 ml acetonitrile and 2 ml deionized water and shaken vigorously for 30 seconds by hand followed by 15 minutes on a mechanical shaker. After addition of 1.5 g QuEChERS-Mix (18) the sample was shaken for 30 seconds by hand and centrifuged for 5 minutes at 1800 G. The organic supernatant was diluted with 2 ml of water and subjected to a clean-up step by solid phase extraction. An Oasis WAX cartridge (60 mg sorbent, 3 ml volume) was used as solid phase matrix. After conditioning with 2 ml of a 0.1% aqueous formic acid solution and 2 ml methanol the sample was applied to the sorbent at a flow rate of 2 ml/min and then washed with 2 ml of a 2% aqueous solution of formic acid and 2 ml methanol. Elution was performed with 2 ml 0.1% ammonia in methanol. The eluate was evaporated to dryness at 40 °C in a stream of nitrogen and the residue dissolved in 0.25 ml methanol-water mixture (50:50 V/V). Any turbidity that appeared was removed with a 0.45 µm syringe filter.

Instrumental analysis of PFAA. Analysis was performed according to Falk et al. (19) using HPLC-tandem mass spectrometry with negative ionization. Data were collected on an Alliance 2695 separations module coupled to a Xevo TQD (Waters GmbH, Eschborn, Germany). Separation was performed on a binary gradient of a 2 mmol ammonium acetate solution in methanol (A) and a 2 mmol ammonium acetate solution in water (B), starting with 55% A and 45% B, increasing to 95% A and 5% B within 5 min, further increasing to 98% A and 2% B at 6.6 min, returning to 55%


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A and 45% B after 10 min and holding initial conditions for 7 minutes. A 20 µL aliquot of the sample was injected onto a Luna C18 HPLC column, 150 x 3 mm, 3 µm particle size at a flow rate of 0.25 ml/min and a column temperature of 35 °C.

Quality assurance. When analysis of biowaste and sewage sludge began in 2010 there were no international or German codes for analysis of these matrices. In order to assure that results met requirements for quality in 2010, we prepared, organized and carried out an interlaboratory comparison for diverse matrices in which 19 laboratories took part. We provided the participating laboratories with, among others, real contaminated sewage sludge, biowaste and animal feed. Later, we also took part in round robin testing performed on soil/sewage sludge (Interregional round robin testing LÜRVE 2009-2016) as well as in validation round robin testing for solid matter by the German Institute for Standardization, which, in addition to soil and sewage sludge was also validated for testing biowaste. Quality assurance biowaste. Sample free procedural blanks were tested concurrently each day to eliminate the possibility of cross contamination. Standards with concentrations between 0 and 50 µg/L (0 (blank), 1, 5, 10, 20, 50 µg/L) were used in calibration. Samples that showed concentrations higher than the highest calibration standard (50 µg/L) were diluted to within the calibration range. All concentrations found in samples were corrected by recovery of the corresponding

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standard (for recovery rates of 13C-labeled standards see Table 1 of the supporting information). The arithmetic means of the substances found at concentrations above the limit of quantification of 1 µg/kg were: PFBA 140 µg/kg, PFPeA 57 µg/kg, PFHxA 57 µg/kg, PFHpA 17 µg/kg, PFOA 70 µg/kg, PFBS 93 µg/kg, PFHxS 157 µg/kg and PFOS 270 µg/kg. Our resultant Z-scores for all eight of the determinable (> 1 µg/kg) components were < 2.0 and > -2.0. In validation of round-robin testing for solid matter, the German Institute for Standardization established the rule that a laboratory has successfully passed the round-robin test if the Z-score is between -2 and +2. The substancespecific recovery rates in biowaste were between 84% for PFBS and 95.6% for PFOA.


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Quality assurance sewage sludge. Sample free procedural blanks were tested concurrently each day to eliminate the possibility of cross contamination. Standards with concentrations between 0 and 50 µg/L (0 (blank), 1, 5, 10, 20, 50 µg/L) were used in calibration. Samples that showed concentrations higher than the highest calibration standard (50 µg/L) were diluted to within the calibration range. All concentrations found in samples were corrected by recovery of the

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standard. The arithmetic means of the substances found at concentrations above the limit of quantification of 1 µg/kg were: PFOA 3 µg/kg, PFNA 2 µg/kg, PFDA 11 µg/kg, PFUdA 3 µg/kg, PFDoA 5 µg/kg, und PFOS 11 µg/kg. Our resultant Z-scores for all six of the determinable (> 1 µg/kg) components were < 2.0 and > -2.0. In validation of round-robin testing for solid matter, the German Institute for Standardization established the rule that a laboratory has successfully passed the roundrobin test if the Z-score is between -2 and +2. In sewage sludge the recovery rates were between 69.9% for PFUnDA and 134% for PFDA.

Statistical evaluation. Since many of the analyzed samples showed values below the limit of quantification (LOQ) of 1 µg/kg the median value (50th percentile) is generally also < LOQ, which creates considerable difficulty for statistical analysis. For this reason, the arithmetic mean and a trimmed mean were additionally calculated. The latter is an arithmetic mean calculated from those samples between the 5th and 95th percentile of the frequency distribution of concentrations. By this method it is assured that outliers do not inadmissibly falsify the means. Since the value < LOQ is always assigned a value of 0.0 in statistical evaluations it is possible that the mean shown is less than the LOQ. To determine whether the concentrations of individual PFAA in one matrix are greater than in others the Wilcoxon Signed Rank Test (WSR) was calculated for each substance (20). The WSR tests the null hypothesis that two distributions are the same. The alternative hypotheses were formulated: "Concentration in sewage sludge is higher", and "Concentration in biowaste is higher". In cases in which the level of significance is < 0.05, the null hypothesis is rejected and the alternative hypothesis chosen. The calculations were carried out using the Software R 3.4.1 and application of the function "wilcox.test". ACS Paragon Plus Environment

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RESULTS AND DISCUSSION Comparison of single substances in sewage sludge and biowaste. The minima for every tested substance was below the LOQ of 1 µg/kg, both in sewage sludge and in biowaste. The maximum concentrations in sewage sludge were between 6.1 µg/kg DW (PFUnDA) and 698 µg/kg DW (PFOS) and in biowaste between < LOQ and 29.0 µg/kg DW (PFHxS). Whereas in sewage sludge all of the substances examined could be found, PFUnDA, PFTrDA and PFTeDA were not detected in any of the biowaste samples. For most of the substances examined, more than half of the values were < LOQ. The only substances for which a median greater than the LOQ could be detected were PFOA and PFOS in both matrices, PFDA in sewage sludge and PFHxA in biowaste. This shows a non-normally distributed strong variability in PFAA concentrations in the matrices (Figure 1). This is confirmed by the fact that for almost all of the substances and matrices the standard deviation is greater than the mean (see supporting information Table 2).

Insert Figure 1

With the aid of the Wilcoxon Signed Rank test it was possible to show that the concentration of most long-chain PFAA was higher in sewage sludge than in biowaste (see supporting information Table 3), which may be the result of the strong adsorption of the long-chain PFAA in sewage sludge. The concentration of three (PFBS, PFHxA, PFHpA) of five short-chained substances was significantly higher in biowaste than in sewage sludge (see supporting information Table 3). A reason for the low concentration of short-chain substances in sewage sludge is their very good solubility in water and low adsorption to organic carbon (4). Compounds with more than 10 C atoms (PFUdA, PFDoDA, PFTrDA, PFTeDA) are not found at all, or in very low concentrations in compost, as shown previously in systematic studies of carryover (6-9). This appears to be the result of long-chain molecules not being transported to upper parts of the plant after uptake by the root system. Long-chain molecules can well be taken up in very high concentrations by the roots as demonstrated by the systematic studies of Krippner et al. (6). In addition, due to their strong adsorptive ACS Paragon Plus Environment

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properties, long-chain molecules are only available for plant uptake in low concentrations in soil water. Distributions of the two components regulated by the German fertilizer regulation (see Introduction), PFOA and PFOS, are very dissimilar: Whereas there was no significant difference in concentration of PFOA between the two matrices, the concentration of PFOS was significantly higher in sewage sludge. The median values of the two vary by a factor of five. This reflects the difference in adsorption coefficient KOC which is seven times higher for PFOS (22). Comparison of composite parameters in sewage sludge and biowaste. Observing the concentrations of the individual substances analyzed here indicates that the fingerprints/patterns of the two matrices, sewage sludge and biowaste differ from one another. Accordingly, the next step was to determine the sums of the individual concentrations of the lead or marker substances PFOA and PFOS, the sum of the individual concentrations of short-chain PFAA (from 4-7 carbon atoms), the sum of the individual concentrations of the long-chain PFAA (9 to 13 carbon atoms), as well as the sum of the individual concentrations of all PFAA analyzed and to generate a graphic representation of these concentrations, as seen in Figure 2. The sum of PFOA and PFOS is significantly (p < 0.001) higher in sewage sludge (median of 11.7 µg/kg DW) than in biowaste (median of 3.6 mg µg/kg DW). The situation is different for the short-chain substances. In this case the sum of the concentrations of the short-chain molecules does not differ significantly between the two matrices. Within the individual matrices the sum of the short-chain substances is significantly higher in biowaste than the sum of the long-chain molecules (p < 0.001). In sewage sludge there is no significant difference between long- and short-chain molecules. The concentration sum of all PFAA is significantly higher (p < 0.001) in sewage sludge (median of 29.1 µg/kg DW) than in biowaste (median of 8.7 µg/kg DW).

Insert Figure 2


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Fingerprint and fractions of short-chain, long-chain and lead substances. The classification of substances into "groups" (PFOA and PFOS, short-chain PFAA and long-chain PFAA) shows that sewage sludge and biowaste exhibit different concentrations per group, different total concentrations and thus differing substance fingerprints. To illustrate this, Figure 3 shows the fraction of the "groups" related to the total concentrations. Whereas the percentage of long-chain PFAA in sewage sludge (24.5%) is comparable to that in biowaste (17.6%), the percentages of the groups PFOA and PFOS as well as of short-chain substances differ greatly between these two matrices. PFOA and PFOS make up a proportion of 60.5% in sewage sludge, whereas they only amount to 35.6% in biowaste. The situation is reversed in regard to short-chain PFAA where the percentage is just 14.1% in sewage sludge and 46.8% in biowaste. Even though PFOA and PFOS were considered in a separate group, they are generally part of the long-chain PFSS. Thus, long-chain PFAA made up 85.9% and short-chain PFAA just made up 14.1% of the total concentration in sewage sludge. The values for biowaste are, by comparison, quite similar to one another: 53.2% long-chain and 46.8% short-chain PFAA. Therefore, it can be argued that sewage sludge serves as a sink for long-chain PFAA while both groups play similar roles in biowaste.

Insert Figure 3

Amounts exceeding the mandatory labeling and maximum permissible values. The German directive for use of fertilizers (16) specifies a maximum permissible concentration of 100 µg/kg DW for the sum of PFOA and PFOS. Sewage sludge that exceeds this value must generally be incinerated at temperatures between 850 °C and 900 °C (23). When the sum exceeds 50 µg/kg DW (sum of PFOA and PFOS) the material must be labeled as such (mandatory labeling threshold). Of the 201 sewage sludge samples tested in this study, seven (equivalent to 3.8%) showed concentrations with values > 100 µg/kg DW, with maximum concentration of 702 µg/kg DW (4 µg/kg PFOA and 698 µg/kg PFOS). A total of 13 additional samples (equivalent to 6.5%) exceeded the mandatory labeling threshold (not including those with values > 100 µg/kg DW). None of the 45 biowaste


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samples examined here contained more than 50 µg/kg DW of the sum of PFOA and PFOS. The maximum values found in biowaste were 15.5 µg/kg DW (7.3 µg/kg PFOA and 8.2 µg/kg PFOS). No PFOA or PFOS was found in 18 sewage sludge samples (equivalent to 9%), or in 7 biowaste samples (equivalent to 15.6%).

Comparison of the results for sewage sludge obtained in this study with results from other international studies. When comparing the results obtained in this study with those from other reports from international literature it is important to realize that the paths of entry for PFAA can be very diffuse. Any number of factors may play a role in the concentration of PFAA found in sewage sludge, including the presence of PFAA-emitting industries within the catchment of the water treatment plant, the number of inhabitants in the same area, as well as country specific legal and technical characteristics in regard to the discharge of sewage into the water treatment plants. In order to classify the results of this study in an international context, selected results from published studies (only those international studies were chosen in which at least a comparable number of compounds were analyzed in sewage sludge as were analyzed in the present study, and in which range and/or arithmetic mean were listed). on sewage sludge are presented in Table 1. Only those substances analyzed in the present study were selected for presentation in the table. The results of the components analyzed in the literature are in the same order of magnitude as those reported in this study. The maximum concentrations of the short-chain molecules PFPeA, PFHxA and PFHpA in this study were highest, compared to other studies. The values of PFOA, PFDA, PFUnDA and PFTeDA from the studies in South Korea are comparatively higher than in the other studies shown here. This has been explained as the result of the influence of fabric/textile and paper mills, the dyeing industry, oil/chemical and metal-plating/processing industries (24). Two individual values especially stand out in Table 1. On the one hand the maximum concentration of 3209 µg/kg DW for PFUnDA in sewage sludge from Greece (25) and the maximal concentration of 7305 µg/kg DW for PFOS in the study from China (26). While there is no known explanation for the high PFUnDA


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value, the exceptional PFOS value is considered to be the result of possible sample inhomogeneities of unknown source.

Insert Table 1

Mass balance of spreading sewage sludge on soil. In the year 2015 a total of 617,863 tons of sewage sludge was used in Germany (427,736 tons as fertilizer in agriculture and 190,127 tons in landscape engineering) (17). Based on the trimmed means of the measured PFAA concentrations in sewage sludge it is possible, assuming that the measured values are representative, to estimate the absolute amounts of the individual compounds spread on agricultural lands in Germany (Table 2). Accordingly, the amount of PFAA (sum of the individual compounds) spread with the sewage sludge on agricultural lands is estimated to be 15.3 kg. PFOA and PFOS together account for 9.3 kg, (PFBS to PFHpA) for 2.2 kg and the sum of all long-chain molecules (without PFOA and PFOS) for 3.9 kg. Therefore, as a result of the transition to soil water and uptake by fodder plants, the spreading of sewage sludge on agricultural land may lead to PFAA reaching the animal and the human food chain. (10, 11). In addition, PFAA may be transferred more deeply into the soil and ultimately leach down to the ground water (9).

Insert Table 2

By using sewage sludge as fertilizer, an estimated total of 15.3 kg/year of PFAA (Table 2) are distributed onto agricultural land in Germany.

ACKNOWLEDGEMENTS We wish to express our gratitude to our technical staff Maria Arabatzoudi, Jan Krolop and Matthias Wohlrab for their help in sample preparation and analysis. Bernd Schwesinger, also of the Hessian State Laboratory, also earns our gratitude for sampling sewage sludge and biowaste, as well as the ACS Paragon Plus Environment

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detailed description of sampling techniques. We are indebted to Jörg Winkler for preparation of the graphical abstract. Our thanks also to Gabi Walper and Jörg Schäfer from the Kassel Regional Council for providing the data on use of sewage sludge and biowaste. We also wish to thank Barbara Gamb for her assistance in the literature research.

REFERENCES (1) Organisation for Economic Co-Operation and Development (OECD), 2005. Results of Survey on Production and Use of PFOS, PFAS and PFOA, Related Substances and Products/Mixtures Containing these Substances. OECD Environment, Health and Safety Publications. Series on Risk Management No. 19. (2) European Food Safety Authority (EFSA). Perfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA) and their salts. Scientific Opinion of the Panel on Contaminants in the Food chain. The EFSA Journal 2008, 653, 1-131. (3) Stahl, T.; Mattern, D.; Brunn, H. Toxicology of perfluorinated compounds. Environmental Sciences Europe 2011, 23:38 doi:10.1186/2190-4715-23-38. (4) Gellrich, V.; Stahl, T.; Knepper, T.P. Behavior of perfluorinated compounds in soils during leaching experiments. Chemosphere 2012, 87, 1052-1056. (5) Gellrich, V.; Brunn, H.; Stahl. T. Perfluoroalkyl and Polyfluoroalkyl Substances PFASs) in Mineral Water and Tap Water. J. Environ. Sci. Health 2013, 48, 129-135. (6) Krippner, J.; Brunn, H.; Falk, S.; Georgii, S.; Schubert, S.; Stahl, T. Effects of chain length and pH on the uptake and distribution of perfluoroalkyl substances in maize (Zea mays). Chemosphere 2014, 94, 85-90. (7) Lechner, M.; Knapp, H. Perfluorierte Tenside (PFT) in pflanzlichen Lebens- und Futtermittel – Modellversuch versus Realdaten aus Bayern. Lebensmittelchemie 2010, 64, 102. (8) Stahl, T.; Heyn, J.; Thiele, H.; Hüther, J.; Failing, K.; Georgii, S.; Brunn, H. Carry Over of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) from Soil to plants. Arch. Environ. Contam. Toxicol. 2009, 57, 289-298. ACS Paragon Plus Environment

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(9) Stahl, T.; Riebe, R. A.; Falk, S.; Failing, K.; Brunn, H. A long-term lysimeter experiment to investigate the leaching of perfluoroalkyl substances (PFASs) and the carryover from soil to plants – Results of a pilot study. J. Agric. Food Chem. 2013, 61, 1784-1793. (10) Kowalczyk, J.; Ehlers, S.; Fürst, P.; Schafft, H.; Lahrssen-Wiederholt, M. Transfer of perfluorooctanoic Acid (PFOA) and perfluorooctane Sulfonate (PFOS) From Contaminated Feed Into Milk and Meat of Sheep: Pilot Study. Arch. Environ. Contam. Toxicol. 2012, 63, 288-298. (11) Kowalczyk, J.; Ehlers, S.; Oberhausen, A.; Tischer, M.; Fürst, P.; Schafft, H.; LahrssenWiederholt, M. Absorption, Distribution, and Milk Secretion of the Perfluoroalkyl Acids PFBS, PFHxS, PFOS, and PFOA by Dairy Cows Fed Naturally Contaminated Feed. J. Agr. Food Chem. 2013, 61, 2903-2912. (12) Becker, A. M.; Gerstmann, S.; Frank, H. Perfluorooctane surfactants in waste waters, the major source of river pollution. Chemosphere 2008, 72, 115–121. (13) Bossi, R.; Strand, J.; Sortkjaer, O.; Larsen, M. M. Perfluoroalkyl compounds in Danish wastewater treatment plants and aquatic environments. Environ. Int. 2008, 34, 443–550. (14) Higgins, C. P.; Field, J. A.; Criddle, C. S.; Luthy, R. G. Quantitative determination of perfluorochemicals in sediments and domestic sludge. Environ. Sci. Technol. 2005, 39, 3946–3956. (15) Sindiku, O.; Orata, F.; Weber, R.; Osibanjo, O. Per- and polyfluoroalkyl substances in selected sewage sludge in Nigeria. Chemosphere 2013, 92, 329-335. (16) Düngemittelverordnung: Verordnung über das Inverkehrbringen von Düngemitteln, Bodenhilfsstoffen, Kultursubstraten und Pflanzenhilfsmitteln (Düngemittelverordnung - DüMV), Ausfertigungsdatum: 05.12.2012. Düngemittelverordnung vom 5. Dezember 2012 (BGBl. I S. 2482) (17) German Federal Statistical Office, 2017. https://www.destatis.de/DE/ZahlenFakten/GesamtwirtschaftUmwelt/Umwelt/UmweltstatistischeEr hebungen/Wasserwirtschaft/Tabellen/TabellenKlaerschlammverwertungsart.html


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Accessed 6 Nov 2017. Only available in German language. (18) Anastassiades, M.; Lehotay, S.J.; Stajnbaher, D.; Schenck, F.J. Fast and Easy Multiresidue Method Employing Acetonitile Extraction/partitioning and "Dispersive Solid-phase Extraction" for the Determination of pesticide Residues in produce. J. AOAC Int. 2003, 86, 412-431. (19) Falk, S.; Brunn, H.; Schröter-Kermani, C.; Failing, K.; Georgii, S.; Tarricone, K.; Stahl, T. Temporal and spatial trends of perfluoroalkyl substances in liver of roe deer (Capreolus capreolus). Environ. Pollut. 2012, 172, 1-8. (20) Helsel, D.; Hirsch R. In Book Statistical Methods in Water Resources. US Geological Survey, Techniques of Water-Resources Investigations 2002, Book 4, Chapter A3. (21) Felizeter, S.; McLachlan, M. S.; Voogt, P. de. Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa). Environ. Sci. Technol. 2012, 46, 11735–11743. (22) Milinovic, J.; Lacorte, S.; Vidal, M.; Rigol, A. Sorption behaviour of perfluoroalkyl substances in soils. Sci. Total Environ. 2015, 511, 63–71. (23) German Environmental Agency, 2013. Sewage sludge management in Germany. https://www.umweltbundesamt.de/sites/default/files/medien/378/publikationen/sewage_sludge_ma nagement_in_germany.pdf Accessed 13 Feb 2018 (24) Kim, S.; Im, J. K.; Kang, Y. M.; Jung, S. Y.; Kho, Y. L.; Zoh, K. D. Wastewater treatment plants (WWTPs)-derived national discharge loads of perfluorinated compounds (PFCs). J. Hazard. Mater. 2012, 201-202, 82–91. (25) Stasinakis, A. S.; Thomaidis, N. S.; Arvaniti, O. S.; Asimakopoulos, A. G.; Samaras, V. G.; Ajibola, A.; Mamais, D.; Lekkas, T. D. Contribution of primary and secondary treatment on the removal of benzothiazoles, benzotriazoles, endocrine disruptors, pharmaceuticals and perfluorinated compounds in a sewage treatment plant. Sci. Total Environ. 2013, 463-464, 1067–1075. (26) Ma, R.; Shih, K. Perfluorochemicals in wastewater treatment plants and sediments in Hong Kong. Environ. Pollut. 2010, 158, 1354–1362.


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(27) Sun, H.; Gerecke, A. C.; Giger, W.; Alder, A. C. Long-chain perfluorinated chemicals in digested sewage sludges in Switzerland. Environ. Pollut. 2011, 159, 654–662. (28) Campo, J.; Masiá, A.; Picó, Y.; Farré, M.; Barceló, D. Distribution and fate of perfluoroalkyl substances in Mediterranean Spanish sewage treatment plants. Sci. Total Environ. 2014, 472, 912– 922. (29) Sinclair, E.; Kannan, K. Mass loading and fate of perfluoroalkyl surfactants in wastewater treatment plants. Environ. Sci. Technol. 2006, 40, 1408–1414. (30) Venkatesan, A. K.; Halden, R. U. National inventory of perfluoroalkyl substances in archived U.S. biosolids from the 2001 EPA National Sewage Sludge Survey. J. Hazard. Mater. 2013, 252253, 413-418. (31) Gallen, C.; Drage, D.; Kaserzon, S.; Baduel, C.; Gallen, M.; Banks, A.; Broomhall, S.; Mueller, J.F. Occurrence and distribution of brominated flame retardants and perfluoroalkyl substances in Australian landfill leachate and biosolids. J. Hazard. Mater. 2016, 312, 55-64.


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FIGURE CAPTIONS Figure 1 Box plots of the sampled concentrations in sewage sludge and biowaste. The boxes consist of the median, the 25th and the 75th percentile. Whiskers represent the 10th and the 90th percentile; dots represent the 5th and 95th percentile. Figure 2 Box plots of the accumulated concentrations for different classes of PFAA. The boxes consist of the median, the 25th and the 75th percentile. Whiskers represent the 10th and the 90th percentile; dots represent the 5th and 95th percentile.. Figure 3 Fractions of the sums of PFOA and PFOS, short-chain (C4-C7) PFAA and long-chain (C9-C14) PFAA in sewage sludge and biowaste.


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Table 1: Literature evaluation of PFAA occurrence in sewage sludge. compound PFBS PFPeA PFHxA PFHxS PFHpA PFOA PFOS PFNA PFDA PFUnDA PFDoDA PFTrDA PFTeDA

Switzerlandb Spaind this studya [µg/kg DW] [µg/kg DW] [µg/kg DW] n.a.c 19.5e < LOQ - 10.3 n.a. 97.8 < LOQ - 112 6.2 < LOQ - 16.4 < LOQ – 5.0 < LOQ < LOQ < LOQ - 95.3 < LOQ 4.8 < LOQ - 26.8 11.8 < LOQ - 50.6 < LOQ – 17.0 15 - 750 135 < LOQ - 698 28.7 < LOQ - 23.3 < LOQ – 2.0 1.0 – 13.0 86.4 < LOQ - 42.8 1.0 – 6.0 4.4 < LOQ - 6.4 1.0 – 12.0 0.1 < LOQ - 29.1 2.1 < LOQ - 31.6 < LOQ – 9.0 9.4 < LOQ - 26.0 < LOQ – 8.0

Denmarkf [µg/kg DW] n.a. n.a. n.a. 0.4 – 10.7 n.a. 0.7 – 19.7 9.5 - 156 0.4 – 8.0 1.2 – 32.0 0.5 – 4.4 n.a. n.a. n.a.

Greeceg [µg/kg DW] < LOQ < LOQ – 5.6 < LOQ – 2.2 < LOQ < LOQ – 10.1 1.3 – 16.3 4.6 – 11.3 < LOQ – 10.1 < LOQ – 15.2 < LOQ – 3209 < LOQ – 9.1 < LOQ < LOQ – 6.1

South Koreaj USAh USAi [µg/kg DW] [µg/kg DW] [µg/kg DW] n.a. 2.5 – 4.8 < LOQ – 2.6 n.a. 1.8 – 6.7 n.a. n.a. 2.5 – 11.7 n.a. < LOQ - 18.0 5.3 – 6.6 < LOQ – 10.0 n.a. 1.2 – 5.4 < LOQ – 8.6 18.0 - 241 11.8 -70.3 7.4 - 400 < LOQ – 65.0 306 - 618 7.2 - 410 n.a. 3.2 – 21.1 1.9 - 24 < LOQ – 91.0 6.9 – 59.1 19.0 - 160 < LOQ - 115 2.8 – 38.7 18.0 – 69.0 n.a. 4.5 - 26.0 13.0 - 160 n.a. n.a. 5.0 - 28 n.a. n.a. n.a.

Chinak [µg/kg DW] 0.6 - 6.4 0.5 – 10.1 0.3 – 27.8 < LOQ – 4.0 n.a. 1.3 – 15.7 3.1 - 7305 0.8 – 23.0 0.3 – 15.2 < LOQ – 7.8 < LOQ – 8.6 0.2 – 19.0 0.2 – 46.0

Australial [µg/kg DW] 7.413 n.a. 2.6 n.a. n.a. 11.0 67.0 1.2 29.0 1.6 9.9 0.8 7.0

LOQ: Limit of Quantification this Study, n=201 b Sun et al., 2011, n=31(20 different waste water treatment plants)27 c n.a.: not analyzed d Campo et al., 2014, n=2128 e In this publication mean values from two studies (2010 und 2011) are listed. In this table the mean of both values was calculated. f Bossi et al. 2008, n=6 (6 WWTP)13 g Stasinakis et al., 2013, n=14 (1 sewage treatment plant, Athens)25 h Sinclair et al., 2006, n=10 (2 different WWTP)29 i Venkatesan et al., 2013, n=110 (94 WWTP)30 j Kim et al., 2012, n=45 (domestic WWTP n=15, industrial WWTP n=15, mixed domestic and industrial WWTP n=15)24 k Ma and Shih, 2010, n=13 (6 WWTP)26 l Gallen et al., 2016, n=1631 a

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Table 2 Trimmed means and the subsequent calculated yearly sum of sewage sludge applied to agricultural lands in Germany calculated per individual substance trimmed means applied amount Individual substance [µg/kg DW] [kg absolute] 0.1 0.1 PFBS 2.4 1.5 PFPeA 0.6 0.4 PFHxA 0.3 0.2 PFHxS 0.1 0.0 PFHpA 5.0 3.1 PFOA 10.0 6.2 PFOS 1.2 0.7 PFNA 3.3 2.0 PFDA 0.5 0.3 PFUnDA 1.0 0.6 PFDoDA 0.1 0.1 PFTrDA 0.1 0.1 PFTeDA 9.3 Sum PFOA/PFOS 15.0 2.2 Sum C4 to C7 3.5 3.9 Sum C9 to C14 6.3 15.3 Sum of individual concentrations 24.8


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FIGURES

Figure 1


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Figure 2


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Figure 3


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TOC Graphic


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Concentrations and Distribution Patterns of Perfluoroalkyl Acids in

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