Reducing PFAS Contamination To Ensure Water Quality

Application Note From Contamination to Compliance: The Role of Sartorius' Lab Water System in PFAS Detection Reduction of PFAS Contaminants Using Arium® Comfort I UV Mary ‘Tricia’ Vail¹, Dr. Zijie ‘Beryl’ Xia², Andrew Chrisitianson³, Dr. Kunal Kureja*¹ 1. Sartorius Lab Instruments GmbH & Co.KG, Otto-Brenner-Str. 20, 37079 Göttingen, Germany 2. Claros Technologies Inc, 1600 Broadway St NE, Suite 100, Minneapolis, MN 55413, USA 3. Novem Scientific, LLC, 2357 Ventura Drive, Suite 110 Woodbury, MN 55125, USA *Correspondence Email: [email protected] Abstract Per- and Polyfluoroalkyl Substances (PFAS), a family of over 4,700 chemical molecules is known for non-stick and waterproof properties. These versatile compounds find their application in diverse industries, including cosmetics, textiles, and automobiles. Resistance to degradation, they persist in water, soil and atmosphere, contributing to environmental concern. This application note uses two complementary analytical techniques: liquid chromatography – mass spectrometry and combustion ion chromatography to discern how the Arium® Comfort I UV reduces PFAS contaminants concentration below detection limits to up to single-digit ppt or sub-ppt-level (parts per trillion, dependent on the compound) in water. The results show that Arium® Comfort I UV is highly efficient in the reduction of PFAS in water with both the standard and PTFE-free setup. December 04, 2023 Keywords or phrases: Per- and Polyfluoroalkyl Substances (PFAS), PFAS reduction, Ultrapure water, ASTM Type I water, Arium®, LCMS, CIC TOF For further information, visit sartorius.com 2 Introduction PFAS are a group of synthetic chemicals widely used in industrial and consumer products, such as non-stick cookware, waterproof clothing, and firefighting foam, due to their unique properties. However, their persistence in the environment and potential adverse health effects have raised concerns about their presence in water sources, including drinking water. Human exposure to PFAS can occur through ingestion of contaminated food and water, inhalation of dust and air, and skin contact with products containing PFAS. Once released into the environment, PFAS can persist for a long time and can leach into soil and water, potentially contaminating drinking water sources and harming wildlife (Figure 1).¹,² This application note discusses how the Arium® Comfort I UV effectively reduces PFAS contaminants concentration below detection limits to up to single-digit ppt or sub-ppt-level (parts per trillion, dependent on the compound) in water. Figure 1: Main PFAS Exposure Pathways for Humans and Biota² Human Biota River & Groundwater Food Drinking water Breast milk Exposure Media Wastewater Landfill waste Air & dust Soil & farmland Environmental Release Products Manufacturing PFAS using | producing industries Aqueous Film-Forming Foam Food containers and packaging Cookware (Teflon) Furniture Fabric protection Carpet and rugs 3 Achieving Below Detection Limit Removal The combination of activated carbon, RO treatment, and resin ion exchange in the Arium® Comfort I UV enables the reduction of PFAS concentrations to below detection limits in tap water. The system ensures the production of high-quality water that is verified to reduce the risk of PFAS contamination from the original water source, meeting the stringent purity requirements of various applications. Treating Highly Contaminated PFAS Solutions The effectiveness of the Arium® Comfort I UV is not limited to potable water. The system has been tested and proven to treat highly contaminated solutions containing up to ~4 ppb (parts per billion) of various PFAS compounds. This capability highlights the system’s robustness and efficiency in addressing challenging contamination scenarios. Materials • Arium® Comfort I UV • Arium® Bag Tank • LCMS System (Shimadzu 8060 LCMS and PromoChrom SPE03) • CIC-System (Metrohm Custom Halogen Analyzer) • Extracting tools and equipment Arium® Comfort I UV Sartorius offers the compact, environmentally friendly, reliable, and easy-to-use Arium® Comfort I for producing ASTM Type 1 ultrapure water and Type 3 pure water combined in a single system. The system contains state-ofthe-art reverse osmosis technology and a unique cartridge specifically to produce the highest ultrapure water quality. Compared to conventional water systems, the Arium® Comfort I optimizes water consumption using the integrated iJust control unit. This unique touch display with intuitive menu navigation ensures the utmost ease of use. With the optionally integrated TOC monitor, its compact design, and the SD card slot, the Arium® Comfort I is the ideal choice for demanding laboratory applications. Ultrapure Water Purification System Overview The Arium® Comfort I UV is a comprehensive water treatment solution designed to produce ultrapure water from in- house potable water for various applications, ensuring the reduction of a wide range of contaminants, including traces of metal ions, organic contamination and PFAS. The system employs a multi-stage approach combining activated carbon, reverse osmosis technology, and resin ion exchange to achieve efficient PFAS removal. PFAS Removal Process PFAS Removal Process³ Our Arium® Comfort I UV employs a multi-stage process to eliminate PFAS contaminants from potable water, ensuring the highest level of water purity. Reverse Osmosis (RO) Module The process begins with the water passing through the RO module. The cornerstone of our PFAS removal strategy lies in the implementation of advanced RO technology.⁴,⁵ RO has proven to be remarkably efficient in removing PFAS compounds, boasting a removal rate of up to 99% of PFOS from the feedwater.⁶ This includes the drastic reduction of both long-chain and short-chain PFAS molecules (C4 - C14), demonstrating the technology’s comprehensive efficacy. Activated Carbon Filtration Following RO filtration, the water enters the activated carbon filtration stage. Activated carbon, renowned for its exceptional adsorption properties, further targets PFAS molecules. This step enhances the purification process by capturing remaining PFAS compounds and other organic impurities.⁷,⁸ Resin Ion Exchange The final stage involves resin ion exchange, a process that further polishes the water by exchanging undesirable ions, including remaining traces of PFAS, with ions on the resin. This step ensures that even the minute concentrations of PFAS that may have passed through earlier stages are effectively removed.⁴ 4 Arium® Bagtank The pure water is stored in the innovative enclosed Arium® Bagtank system. This system protects the prepared pure water against secondary contamination. The Sartorius Bagtank system enables consistent water quality over a prolonged period, thereby ensuring permanent, reproducible results. Unlike conventional water reservoirs, the Arium® Bag offers a high level of user safety and time savings, as there is no need for a complicated cleaning procedure with chemicals. LCMS Condition LCMS data was obtained using a Shimadzu 8045 UPLC-QQQ instrument with internal standards. The instrument is modified to reduce PFAS contamination from the instrument components and LC solvents including a delay column. The chromatographic separation is performed with a BEH C18 column (2.1 × 100 mm, 2.1 µm) using a gradient (Solvent A and B follows EPA draft method 1633). MS source conditions are adjusted to allow optimized performance for all 40 PFAS compounds. Data analysis is done with the LabSolution software. Storage Samples were stored in 4 °C environment prior to the extraction. Extraction Samples were taken out of the refrigerated environment and allow to return to room temperature. Method blanks and lab control samples were created according to the lab procedure. All samples, method blank, and lab control samples contain the same amount of spike of surrogate compounds (extracted internal standards). The samples were mixed by inverting the bottle gently backing forth for approximately one minute. The samples were loaded on PromoChrom SPE03 automatic solid phase extraction system. The 1633 method solid phase extraction method was used for these samples. CIC-Condition Combustion Ion Chromatography (CIC) data was obtained using a customized halogen analyzer from Metrohm for the analysis of Total Organofluorine (TOF) data per sample, allowing for a direct comparison with LCMS data. Briefly, a known amount of sample is combusted in a greater than 1,000 °C oven and the gas phase containing total ions is condensed in an absorber solution with subsequent analysis by ion chromatography. This result gives the total fluorine (TF) value of the sample. An Asupp7 column is used in standard conditions (EPA 300.0) to separate and quantify the components which are detected by conductivity. Simultaneously, the same sample is sent directly to a different IC to analyze for inorganic fluorine (IF, as free fluoride). This result gives the inorganic fluoride value. TOF may now be calculated by TF – IF. The analysis is non-speciated, focusing on the collective impact of PFAS, and offers a streamlined approach with significantly reduced sample preparation. This comprehensive TOF perspective provides prompt insights into unknowns, potentially negating the need for subsequent advanced testing. In this analytical setup, the Custom Halogen Analyzer has been optimized after receipt by Metrohm and features a reporting limit of 7.5 ppb. Result LCMS Results The method of detection limit (MDL) and the method reporting limits (MRL) for LCMS are shown in Table 1. The last complete validation of the LCMS was performed in Q2 2023 and the analysis were performed in Q2 and Q3 2023. Any compounds with T in the analyte indicate that both branched and linear isomers are in quantitation consideration. Table 1: MDL and MRL Values of the PFAS Analyte MDL (ppt) MRL (ppt) PFBA 2.100 5 PFPeA 0.399 1 PFHxA 0.375 1 PFHpA 0.419 1 PFOA 0.507 2 PFNA 0.547 2 PFDA 0.274 1 PFUnA 0.399 1 PFDoA 0.554 2 PFTrDA 0.759 2 PFTeDA 0.395 1 T-NMeFOSAA 0.212 1 T-NEtFOSAA 0.514 2 PFBS 0.503 2 PFPeS 0.489 2 T-PFHxS 0.427 1 PFHpS 0.500 2 T-PFOS 0.351 1 PFNS 0.395 1 PFDS 0.373 1 PFDoS 0.748 2 4:2 FTS 1.389 5 6:2 FTS 2.215 5 8:2 FTS 2.550 10 PFOSA 0.445 1 5 Experiment I Samples of water mimicking a normal lab setting by connecting the system to the tap water. Two different Arium® Systems were chosen for this experiment. The first Arium® Comfort UV I system has the standard setup, which is equipped with virgin PE and PTFE tubing (Setup I). The second Arium® Comfort I UV system is only equipped with PE tubing (Setup II). The samples were collected at (see Figure 2): • Feed water • Post RO-treatment and before the water was stored in Arium® Bagtank • At point of use of the system (without any final filter) Analyte MDL (ppt) MRL (ppt) HFPO-DA 0.628 2 ADONA 0.973 2 9Cl-PF3ONS 0.662 2 11Cl-PF3OUdS 1.958 5 N-MeFOSA 0.612 2 N-EtFOSA 0.672 2 N-MeFOSE 10.668 30 N-EtFOSE 6.733 20 3:3 FTCA 0.412 1 5:3 FTCA 3.099 10 7:3 FTCA 3.483 10 PFMPA 0.314 1 PFMBA 0.350 1 NFDHA 0.907 2 PFEESA 0.308 1 Figure 2: Flowchart of Arium® Comfort I UV. Blue Stars Mark the Point of Sampling Conductivity measurement (feed water) Pretreatment cartridge Pump Inlet (feed water) RO module #1 Conductivity measurement (product water | permeate) (RO) Arium® Bagtank RO module #2 Outlet (waste water) Outlet (waste water) Arium® Comfort kit Pump Inlet bagtank UV lamp (185 | 254 nm) Conductivity measurement ultrapure water TOC 6 Results I The Arium® Comfort I UV systems were installed in Woodbury, MN, a location with a historical presence of PFAS in tap water. The analysis conducted three times and detailed in Table 2 with results reported in ppt, reveals that the PFAS content in the feed water is consistently reduced to levels below the limit of detection after undergoing RO-treatment. Furthermore, there is no discernible PFAS leakage during the polishing step of the system. Table 2: PFAS Results of the Experiment I. The Table Shows the Average of Three Analysis Content of the Respective PFAS Feed Water (ppt) Post RO (ppt) Point of Use (ppt) Average Standard Deviation Setup I Setup II Setup I Setup II PFBA 233.715 1.778 n.d. n.d. n.d. n.d. PFPeA 5.275 0.102 n.d. n.d. n.d. n.d. PFHxA 1.796 0.026 n.d. n.d. n.d. n.d. PFOA 1.982 0.087 n.d. n.d. n.d. n.d. PFBS 1.374 0.055 n.d. n.d. n.d. n.d. T-PFHxS 1.451 0.277 n.d. n.d. n.d. n.d. T-PFOS 0.926 0.105 n.d. n.d. n.d. n.d. PFHpA n.d. n.d. n.d. n.d. n.d. n.d. PFNA n.d. n.d. n.d. n.d. n.d. n.d. PFDA n.d. n.d. n.d. n.d. n.d. n.d. PFUnA n.d. n.d. n.d. n.d. n.d. n.d. PFDoA n.d. n.d. n.d. n.d. n.d. n.d. PFTrDA n.d. n.d. n.d. n.d. n.d. n.d. PFTeDA n.d. n.d. n.d. n.d. n.d. n.d. T-NMeFOSAA n.d. n.d. n.d. n.d. n.d. n.d. T-NEtFOSAA n.d. n.d. n.d. n.d. n.d. n.d. PFPeS n.d. n.d. n.d. n.d. n.d. n.d. PFHpS n.d. n.d. n.d. n.d. n.d. n.d. PFNS n.d. n.d. n.d. n.d. n.d. n.d. PFDS n.d. n.d. n.d. n.d. n.d. n.d. PFDoS n.d. n.d. n.d. n.d. n.d. n.d. 4:2 FTS n.d. n.d. n.d. n.d. n.d. n.d. 6:2 FTS n.d. n.d. n.d. n.d. n.d. n.d. 8:2 FTS n.d. n.d. n.d. n.d. n.d. n.d. PFOSA n.d. n.d. n.d. n.d. n.d. n.d. HFPO-DA n.d. n.d. n.d. n.d. n.d. n.d. ADONA n.d. n.d. n.d. n.d. n.d. n.d. 9Cl-PF3ONS n.d. n.d. n.d. n.d. n.d. n.d. 11Cl-PF3OUdS n.d. n.d. n.d. n.d. n.d. n.d. N-MeFOSA n.d. n.d. n.d. n.d. n.d. n.d. N-EtFOSA n.d. n.d. n.d. n.d. n.d. n.d. N-MeFOSE n.d. n.d. n.d. n.d. n.d. n.d. N-EtFOSE n.d. n.d. n.d. n.d. n.d. n.d. 3:3 FTCA n.d. n.d. n.d. n.d. n.d. n.d. 5:3 FTCA n.d. n.d. n.d. n.d. n.d. n.d. 7:3 FTCA n.d. n.d. n.d. n.d. n.d. n.d. 7 Feed Water (ppt) Post RO (ppt) Point of Use (ppt) Average Standard Deviation Setup I Setup II Setup I Setup II PFMPA n.d. n.d. n.d. n.d. n.d. n.d. PFMBA n.d. n.d. n.d. n.d. n.d. n.d. NFDHA n.d. n.d. n.d. n.d. n.d. n.d. PFEESA n.d. n.d. n.d. n.d. n.d. n.d. Experiment II Samples for the spiked the 50 L bag filled with reagent water with additional PFAS to test the system’s capability were collected at (see Figure 3): • The reagent water, before it was spiked with PFAS • Post 50 L bag for the spiked PFAS concentration • Post RO-treatment and before the water was stored in Arium® Bagtank • At the outlet of the system (without any final filter) The first Arium® Comfort UV I system has the standard setup, which is equipped with virgin PE and PTFE tubing (Setup I). The second Arium® Comfort I UV system is only equipped with PE tubing. Figure 3: Modified Flowchart for the Spiked Experiment Utilizing Arium® Comfort I UV. Blue Stars Mark the Point of Sampling Conductivity measurement (feed water) Pretreatment cartridge Pump Inlet Arium® Comfort I UV RO module #1 Conductivity measurement (product water | permeate) (RO) Arium® Bagtank RO module #2 Outlet (waste water) Outlet (waste water) Arium® Comfort kit Pump Inlet bagtank UV lamp (185 | 254 nm) Conductivity measurement ultrapure water Arium® Bagtank UP water Spiking solution TOC 8 Results II All reported results in Table 3 are in ppt. The PFAS concentration before spiking was below the limit of detection, consequently, is not presented in the table below. Although one 50 L water bag was intentionally spiked with PFAS, the experiments were conducted a week apart, resulting in an intriguing disparity in the initial concentrations. This variance could be attributed to the practical challenges of effectively mixing PFAS with a 50 L water bag, given the surfactant nature of PFAS, potentially resulting in a heterogeneous distribution within the bag. Furthermore, the instability of certain PFAS compounds at room temperature could contribute to the observed variations. These nuances underscore the importance of careful experimental design and consideration of PFAS properties in ensuring accurate and reliable results. Table 3: Post 50 L Bag, Post RO Treatment and at the Point of Use Concentrations of the PFAS in the Spiked Experiment Setup I Setup II Post 50 L bag (ppt) Post RO (ppt) Point of Use (ppt) Post 50 L bag (ppt) Post RO (ppt) Point of Use (ppt) PFBA 1166.33 n.d. n.d. 4587.67 n.d. n.d. PFPeA 1090.00 1.73 n.d. 4149.00 3.07 n.d. PFHxA 881.43 1.1 n.d. 4482.00 2.43 n.d. PFHpA 17.63 n.d. n.d. 106.83 n.d. n.d. PFOA 502.17 n.d. n.d. 2017.00 n.d. n.d. PFNA 14.40 n.d. n.d. 89.50 n.d. n.d. PFDA 15.10 n.d. n.d. 94.77 n.d. n.d. PFUnA 11.67 n.d. n.d. 94.00 n.d. n.d. PFDoA 7.33 n.d. n.d. 68.00 n.d. n.d. PFTrDA 4.73 n.d. n.d. 44.07 n.d. n.d. PFTeDA 2.87 n.d. n.d. 21.27 n.d. n.d. T-NMeFOSAA 8.70 n.d. n.d. 60.37 n.d. n.d. T-NEtFOSAA 6.30 n.d. n.d. 37.53 n.d. n.d. PFBS 1387.33 n.d. n.d. 8196.00 7.63 n.d. PFPeS 26.50 n.d. n.d. 293.93 n.d. n.d. T-PFHxS 638.07 n.d. n.d. 4103.33 0.87 n.d. PFHpS 47.50 n.d. n.d. 389.47 n.d. n.d. T-PFOS 636.83 n.d. n.d. 4271.00 n.d. n.d. PFNS 17.57 n.d. n.d. 200.47 n.d. n.d. PFDS 11.33 n.d. n.d. 181.50 n.d. n.d. PFDoS 4.30 n.d. n.d. 49.37 n.d. n.d. 4:2 FTS 62.07 n.d. n.d. 342.57 n.d. n.d. 6:2 FTS 54.33 n.d. n.d. 280.57 n.d. n.d. 8:2 FTS 52.37 n.d. n.d. 303.23 n.d. n.d. PFOSA 1.87 n.d. n.d. n.d. n.d. n.d. HFPO-DA 12.83 n.d. n.d. 79.60 n.d. n.d. ADONA 12.57 n.d. n.d. 82.20 n.d. n.d. 9Cl-PF3ONS 10.87 n.d. n.d. 74.97 n.d. n.d. 11Cl-PF3OUdS 3.90 n.d. n.d. 94.60 n.d. n.d. N-MeFOSA 0.73 n.d. n.d. n.d. n.d. n.d. N-EtFOSA n.d. n.d. n.d. n.d. n.d. n.d. N-MeFOSE n.d. n.d. n.d. n.d. n.d. n.d. N-EtFOSE n.d. n.d. n.d. n.d. n.d. n.d. 9 Setup I Setup II Post 50 L bag (ppt) Post RO (ppt) Point of Use (ppt) Post 50 L bag (ppt) Post RO (ppt) Point of Use (ppt) 3:3 FTCA 37.07 n.d. n.d. 522.70 n.d. n.d. 5:3 FTCA 343.23 n.d. n.d. 4651.67 n.d. n.d. 7:3 FTCA 131.30 n.d. n.d. 1218.60 n.d. n.d. PFMPA 24.63 n.d. n.d. 322.03 n.d. n.d. PFMBA 21.40 n.d. n.d. 260.47 n.d. n.d. NFDHA 39.10 n.d. n.d. 523.30 n.d. n.d. PFEESA 35.53 n.d. n.d. 494.13 n.d. n.d. Notable differences in initial concentrations between the two setups distinctly influence the concentrations observed at both the post RO sampling point and the point of use sampling point. Commencing at concentrations in part ppb, the analytes swiftly reach non-detect levels at the point of use. The Arium® Comfort I UV system, producing reagent water, further enhances its significance, providing water of the requisite purity for testing labs engaged in PFAS applications. TOF Results The determination of Total Organic Fluorine (TOF) involves the subtraction of Inorganic Fluorine (IF) from the total, resulting in TOF. To calculate TOF, the inputs required are TF and IF (TOF = TF – IF). The measurement of free fluoride in the sample typically represents IF (Figure 4). The process of obtaining TF involves combusting the sample at temperatures exceeding 1,000 °C to break carbon bonds and form ions. The gas containing the ions of interest is then condensed into an absorption solution and analyzed by Ion Chromatography (IC). Determining IF is achieved by running the sample through IC for free fluoride. The subtraction of these values yields the TOF of the sample. It is crucial to consider various factors, including matrix effects, contaminant ions, and the presence of dissolved or suspended solids and metals. For solids, a different approach is necessary, requiring the extraction of a solid for IF determination even though TF can be directly determined. Figure 4: Scheme of a Fluorine Mass Balance Approach Applying Organically Bound Fluorine Sum Parameters Total Fluorine (TF) (CIC) Inorganic Fluoride (IF) Free fluoride (IC) | “Bound” fluoride Total Organic Fluorine (TOF) TF– IF=TOF Adsorbable AOF (CIC) Total oxidizable precursor TOPS (LCMS) Extractable EOF (CIC) Plasma induced gamma emission (PIGE) Speciated Analytes (LCMS) Adhering to the same experimental design and utilizing identical sample points as outlined in the LCMS schema, the chosen methodology involves employing CIC to analyze TOF data on a per-sample basis, allowing for a direct comparison with LCMS data. This non-speciated analysis is specifically focused on evaluating the combined impact of PFAS. A comprehensive examination of TOF provides swift insights into unknown elements, offering a rapid understanding. Table 4: Total Organofluorine (TOF) via Combustion Ion Chromatography (CIC) Sample ID Setup I Setup II Experiment I Tap Water (ppb) <7.5 <7.5 Post RO (ppb) <7.5 <7.5 Point of Use (ppb) <7.5 <7.5 Experiment II Pre-Spiking (ppb) <7.5 <7.5 Post 50 L bag (ppb) <7.5 24.3 Post RO (ppb) <7.5 <7.5 Point of Use (ppb) <7.5 <7.5 The Arium® Comfort I UV system consistently produces highquality reagent water, making it well-suited for PFAS testing labs. The TOF data serves as a valuable complement to LCMS data, ensuring a more comprehensive analysis. Verified non-detects and the confirmed increase after a 50 L Bag in System 2 reinforce the system’s reliability. Importantly, the impact of PFAS contribution is verified, dispelling concerns of hidden analytes driving total organic fluorine levels upward. This underscores the system’s transparency and accuracy in PFAS analysis. 10 Return of Investment The cost analysis provided over a one-year period, as shown in Figure 5 clearly highlights the advantages of transitioning to in-house treated water. With a daily demand of two liters, the investment in the treatment device starts to yield significant financial benefits in as little as four months, ultimately resulting in substantial cost savings within the course of a year. Furthermore, this approach aligns with sustainability goals by eliminating the need for glass bottles, reducing pollution associated with shipping, and eliminating the necessity for extensive storage space. Figure 5: Comparison of Expenses Between In-House Produced Arium®-Water Type I (Ultrapure Water) and Bottled Water (LCMS Grade, With PFAS Content Below Detection Limit) 30,000 0 25,000 20,000 15,000 10,000 5,000 Cost [US $] Duration [Month] Return of Investment 2 4 6 8 10 12 Bottled Water Arium® Water Note: Calculation based on following assumptions: two liters water consumption per working day, 20 working days per month, Arium® Comfort I UV system plus consumables list price = $9,590, annual Arium® Comfort I UV consumables list price = $2,400 and costs bottled water LCMS grade = $60/liter*. * TH.Geyer 29.8.23, 10:16 Conclusion The Arium® Comfort I UV offers a comprehensive solution for the reduction of PFAS contaminants from tap water, reducing their concentrations to below limit of detection. Through a combination of activated carbon filtration, reverse osmosis treatment, and resin ion exchange, the system ensures the production of ultrapure water suitable for a wide range of applications. Additionally, the system’s ability to treat highly contaminated solutions (~4 ppb) demonstrates its efficacy in managing even the most challenging PFAS contamination scenario , whether the system is equipped with PE tubing alone or both PE and PTFE tubing (see Setup I and II). For analytical laboratory and applications demanding the highest water quality standards, the Arium® Comfort I UV provides a reliable and effective solution for PFAS reduction. 11 References 1. Racz, L. & Kempisty, D. M. PFAS. Today and Tomorrow. In Forever chemicals. Environmental, economic, and social equity concerns with PFAS in the environment, edited by D. M. Kempisty & L. Racz (CRC Press, Boca Raton, 2021), pp. 3–21. 2. Bălan, S. A. & Meng, Q. PFASs in Consumer Products. Exposure and Regulaatory Approches. In Forever chemicals. Environmental, economic, and social equity concerns with PFAS in the environment, edited by D. M. Kempisty & L. Racz (CRC Press, Boca Raton, 2021), pp. 52–86. 3. Kempisty, D. M. & Racz, L. (eds.). Forever chemicals. Environmental, economic, and social equity concerns with PFAS in the environment (CRC Press, Boca Raton, 2021). 4. Zaggia, A., Conte, L., Falletti, L., Fant, M. & Chiorboli, A. Use of strong anion exchange resins for the removal of perfluoroalkylated substances from contaminated drinking water in batch and continuous pilot plants. Water research 91, 137–146; 10.1016/j.watres.2015.12.039 (2016). 5. Bolan, N. & Hoang, S. A. Landfills as Sources of PFAS Contamination of Soil and Groundwater. In Forever chemicals. Environmental, economic, and social equity concerns with PFAS in the environment, edited by D. M. Kempisty & L. Racz (CRC Press, Boca Raton, 2021), pp. 119–142. 6. Tang, C. Y., Fu, Q. S., Robertson, A. P., Criddle, C. S. & Leckie, J. O. Use of reverse osmosis membranes to remove perfluorooctane sulfonate (PFOS) from semiconductor wastewater. Environmental science & technology 40, 7343– 7349; 10.1021/es060831q (2006). 7. Horst, J. et al. Water Treatment Technologies for PFAS: The Next Generation. Groundwater Monit R 38, 13–23; 10.1111/ gwmr.12281 (2018). 8. Berretta, C., Mallmann, T., Trewitz, K. & Kempisty, D. M. Removing PFAS from Water. from Start to Finish. In Forever chemicals. Environmental, economic, and social equity concerns with PFAS in the environment, edited by D. M. Kempisty & L. Racz (CRC Press, Boca Raton, 2021), pp. 235–253. Specifications subject to change without notice. Copyright Sartorius Lab Instruments GmbH & Co. KG. Status: 03 | 2024 USA Sartorius Corporation 565 Johnson Avenue Bohemia, NY 11716 Phone +1 631 254 4249 Toll-free +1 800 635 2906 Germany Sartorius Lab Instruments GmbH & Co. KG Otto-Brenner-Strasse 20 37079 Goettingen Phone +49 551 308 0 For further information, visit sartorius.com