Natural nanoparticles (NNPs) in rivers, lakes, oceans and ground water predate humans, but engineered nanoparticles (ENPs) are emerging as potential pollutants due to increasing regulatory and public perception concerns. This Review contrasts the sources, composition and potential occurrence of NNPs (for example, two-dimensional clays, multifunctional viruses and metal oxides) and ENPs in surface water, after centralized drinking water treatment, and in tap water. While analytical detection challenges exist, ENPs are currently orders of magnitude less common than NNPs in waters that flow into drinking water treatment plants. Because such plants are designed to remove small-sized NNPs, they are also very good at removing ENPs. Consequently, ENP concentrations in tap water are extremely low and pose low risk during ingestion. However, after leaving drinking water treatment plants, corrosion by-products released from distribution pipes or in-home premise plumbing can release incidental nanoparticles into tap water. The occurrence and toxicity of incidental nanoparticles, rather than ENPs, should therefore be the focus of future research.

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  1. 1.

    Doria, M. D. Factors influencing public perception of drinking water quality. Water Policy 12, 1–19 (2010).

  2. 2.

    Bhattacharyya, S. et al. Nanotechnology in the water industry, part 1: Occurrence and risks. J. Am. Water Works Ass. 109, 30–37 (2017).

  3. 3.

    Bhattacharyya, S. et al. Nanotechnology in the water industry, part 2: Toxicology and analysis. J. Am. Water Works Ass. 109, 45–53 (2017).

  4. 4.

    Good, K. D., Bergman, L. E., Klara, S. S., Leitch, M. E. & VanBriesen, J. M. Implications of engineered nanomaterials in drinking water sources. J. Am. Water Works Ass. 108, E1–E17 (2016).

  5. 5.

    Tiede, K. et al. How important is drinking water exposure for the risks of engineered nanoparticles to consumers? Nanotoxicology 10, 102–110 (2016).

  6. 6.

    Troester, M., Brauch, H. J. & Hofmann, T. Vulnerability of drinking water supplies to engineered nanoparticles. Water Res. 96, 255–279 (2016).

  7. 7.

    Allaire, M., Wu, H. W. & Lall, U. National trends in drinking water quality violations. Proc. Natl Acad. Sci. USA 115, 2078–2083 (2018).

  8. 8.

    Failure to Act: The Economic Impact of Current Investment Trends in Water and Wastewater Treatment Infrastructure (American Society of Civil Engineers, 2011); http://www.asce.org/failure_to_act_economic_studies/

  9. 9.

    Kistemann, T. et al. Microbial load of drinking water reservoir tributaries during extreme rainfall and runoff. Appl. Environ. Microb. 68, 2188–2197 (2002).

  10. 10.

    Scheurer, M., Storck, F. R., Brauch, H. J. & Lange, F. T. Performance of conventional multi-barrier drinking water treatment plants for the removal of four artificial sweeteners. Water Res. 44, 3573–3584 (2010).

  11. 11.

    Baker, L. A., Westerhoff, P. & Sommerfeld, M. Adaptive management using multiple barriers to control tastes and odors. J. Am. Water Works Ass. 98, 113–126 (2006).

  12. 12.

    Wigginton, N. S., Haus, K. L. & Hochella, M. F. Aquatic environmental nanoparticles. J. Environ. Monit. 9, 1306–1316 (2007).

  13. 13.

    Hochella, M. F. et al. Nanominerals, mineral nanoparticles, and Earth systems. Science 319, 1631–1635 (2008).

  14. 14.

    Liu, H. H. & Cohen, Y. Multimedia environmental distribution of engineered nanomaterials. Environ. Sci. Technol. 48, 3281–3292 (2014).

  15. 15.

    Gottschalk, F., Sun, T. & Nowack, B. Environmental concentrations of engineered nanomaterials: Review of modeling and analytical studies. Environ. Pollut. 181, 287–300 (2013).

  16. 16.

    Keller, A. A. & Lazareva, A. Predicted releases of engineered nanomaterials: From global to regional to local. Environ. Sci. Tech. Lett. 1, 65–70 (2014).

  17. 17.

    Kaegi, R. et al. Release of silver nanoparticles from outdoor facades. Environ. Pollut. 158, 2900–2905 (2010).

  18. 18.

    Kaegi, R. et al. Synthetic TiO2 nanoparticle emission from exterior facades into the aquatic environment. Environ. Pollut. 156, 233–239 (2008).

  19. 19.

    Som, C., Wick, P., Krug, H. & Nowack, B. Environmental and health effects of nanomaterials in nanotextiles and facade coatings. Environ. Int. 37, 1131–1142 (2011).

  20. 20.

    Keller, A. A., McFerran, S., Lazareva, A. & Suh, S. Global life cycle releases of engineered nanomaterials. J. Nanopart. Res. 15, 1692–1709 (2013).

  21. 21.

    Kaegi, R. et al. Release of TiO2 – (Nano) particles from construction and demolition landfills. NanoImpact 8, 73–79 (2017).

  22. 22.

    Kaegi, R. et al. Fate and transformation of silver nanoparticles in urban wastewater systems. Water Res. 47, 3866–3877 (2013).

  23. 23.

    Kiser, M. A. et al. Titanium nanomaterial removal and release from wastewater treatment plants. Environ. Sci. Technol. 43, 6757–6763 (2009).

  24. 24.

    Westerhoff, P., Song, G., Hristovski, K. & Kiser, A. Occurrence and removal of titanium at full scale wastewater treatment plants: Implications for TiO2 nanomaterials. J. Environ. Monit. 13, 1195–1203 (2011).

  25. 25.

    Bauerlein, P. S. et al. Is there evidence for man-made nanoparticles in the Dutch environment? Sci. Total Environ. 576, 273–283 (2017).

  26. 26.

    Song, G. X., Wang, J., Chiu, C. A. & Westerhoff, P. Biogenic nanoscale colloids in wastewater effluents. Environ. Sci. Technol. 44, 8216–8222 (2010).

  27. 27.

    Rice, J. & Westerhoff, P. Spatial and temporal variation in de facto wastewater reuse in drinking water systems across the USA. Environ. Sci. Technol. 49, 982–989 (2015).

  28. 28.

    Bandyopadhyay, S. et al. Microscopic and spectroscopic methods applied to the measurements of nanoparticles in the environment. Appl. Spectrosc. Rev. 47, 180–206 (2012).

  29. 29.

    Neal, C. et al. Titanium in UK rural, agricultural and urban/industrial rivers: Geogenic and anthropogenic colloidal/sub-colloidal sources and the significance of within-river retention. Sci. Total Environ. 409, 1843–1853 (2011).

  30. 30.

    von der Kammer, F. et al. Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies. Environ. Toxicol. Chem. 31, 32–49 (2012).

  31. 31.

    Wagner, S., Gondikas, A., Neubauer, E., Hofmann, T. & von der Kammer, F. Spot the difference: Engineered and natural nanoparticles in the environment-release, behavior, and fate. Angew. Chem. Int. Ed. 53, 12398–12419 (2014).

  32. 32.

    Buffle, J. & Leppard, G. G. Characterization of aquatic colloids and macromolecules. 1. Structure and behavior of colloidal material. Environ. Sci. Technol. 29, 2169–2175 (1995).

  33. 33.

    Baalousha, M., Stolpe, B. & Lead, J. R. Flow field-flow fractionation for the analysis and characterization of natural colloids and manufactured nanoparticles in environmental systems: A critical review. J. Chrom. A 1218, 4078–4103 (2011).

  34. 34.

    Neubauer, E., von der Kammer, F. D. & Hofmann, T. Using FLOWFFF and HPSEC to determine trace metal colloid associations in wetland runoff. Water Res. 47, 2757–2769 (2013).

  35. 35.

    Wang, Z. Y. et al. Biological and environmental interactions of emerging two-dimensional nanomaterials. Chem. Soc. Rev. 45, 1750–1780 (2016).

  36. 36.

    Gondikas, A. P. et al. Release of TiO2 nanoparticles from sunscreens into surface waters: A one-year survey at the Old Danube recreational lake. Environ. Sci. Technol. 48, 5415–5422 (2014).

  37. 37.

    Laborda, F. et al. Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples. Anal. Chim. Acta 904, 10–32 (2016).

  38. 38.

    Hendriks, L., Gundlach-Graham, A., Hattendorf, B. & Guther, D. Characterization of a new ICP-TOFMS instrument with continuous and discrete introduction of solutions. J. Anal. At. Spectrom. 32, 548–561 (2017).

  39. 39.

    Praetorius, A. et al. Single-particle multi-element fingerprinting (spMEF) using inductively-coupled plasma time-of-flight mass spectrometry (ICP-TOFMS) to identify engineered nanoparticles against the elevated natural background in soils. Environ. Sci. Nano 4, 307–314 (2017).

  40. 40.

    Ranville, J. & Montano, M. in Frontiers of Nanoscience Vol. 8 (eds Baalousha, M. & Lead, J.) Ch. 3, 91–121 (Elsevier, New York, 2015).

  41. 41.

    Ranville, J. F. & Beckett, R. in Field Flow Fractionation Handbook (eds Schimpf, M., Caldwell, K. & Giddings, J. C.) Ch. 32, 507–523 (Wiley, New York, 2000).

  42. 42.

    Zanker, H. & Schierz, A. in Annual Review of Analytical Chemistry Vol. 5 (eds Cooks, R. G. & Yeung, E. S.) 107–132 (Annual Reviews, Palo Alto, CA, 2012).

  43. 43.

    Cuss, C. W., Grant-Weaver, I. & Shotyk, W. AF4-ICPMS with the 300 Da membrane to resolve metal-bearing ‘colloids’ <1 kDa: Optimization, fractogram deconvolution, and advanced quality control. Anal. Chem. 89, 8027–8035 (2017).

  44. 44.

    Gallego-Urrea, J. A., Tuoriniemi, J. & Hassellov, M. Applications of particle-tracking analysis to the determination of size distributions and concentrations of nanoparticles in environmental, biological and food samples. Trac. Trends Anal. Chem. 30, 473–483 (2011).

  45. 45.

    Gallego-Urrea, J. A., Tuoriniemi, J., Pallander, T. & Hassellov, M. Measurements of nanoparticle number concentrations and size distributions in contrasting aquatic environments using nanoparticle tracking analysis. Environ. Chem. 7, 67–81 (2010).

  46. 46.

    Westerhoff, P. & Nowack, B. Searching for global descriptors of engineered nanomaterial fate and transport in the environment. Acc. Chem. Res. 46, 844–853 (2013).

  47. 47.

    Rauscher, H., Rasmussen, K. & Sokull-Kluttgen, B. Regulatory aspects of nanomaterials in the EU. Chem. Ing. Tech. 89, 224–231 (2017).

  48. 48.

    Bleeker, E. A. J. et al. Considerations on the EU definition of a nanomaterial: Science to support policy making. Regul. Toxicol. Pharm. 65, 119–125 (2013).

  49. 49.

    Therezien, M., Thill, A. & Wiesner, M. R. Importance of heterogeneous aggregation for NP fate in natural and engineered systems. Sci. Total Environ. 485, 309–318 (2014).

  50. 50.

    Gottschalk, F., Sonderer, T., Scholz, R. W. & Nowack, B. Modeled environmental concentrations of engineered nanomaterials (TiO2, ZnO, Ag, CNT, fullerenes) for different regions. Environ. Sci. Technol. 43, 9216–9222 (2009).

  51. 51.

    Nowack, B. & Bucheli, T. Occurrence, behavior and effects of nanoparticles in the environment. Environ. Pollut. 150, 5–22 (2007).

  52. 52.

    Dale, A. L. et al. Modeling nanomaterial environmental fate in aquatic systems. Environ. Sci. Technol. 49, 2587–2593 (2015).

  53. 53.

    Singh, G., Stephan, C., Westerhoff, P., Carlander, D. & Duncan, T. V. Measurement methods to detect, characterize, and quantify engineered nanomaterials in foods. Compr. Rev. Food Sci. F. 13, 693–704 (2014).

  54. 54.

    Duester, L. et al. Can cloud point-based enrichment, preservation, and detection methods help to bridge gaps in aquatic nanometrology? Anal. Bioanal. Chem. 408, 7551–7557 (2016).

  55. 55.

    Ermolin, M. S. & Fedotov, P. S. Separation and characterization of environmental nano- and submicron particles. Rev. Anal. Chem. 35, 185–199 (2016).

  56. 56.

    Pace, H. E. et al. Determining transport efficiency for the purpose of counting and sizing nanoparticles via single particle inductively coupled plasma mass spectrometry. Anal. Chem. 83, 9361–9369 (2011).

  57. 57.

    Mitrano, D. M. et al. Detecting nanoparticulate silver using single-particle inductively coupled plasma-mass spectrometry. Environ. Toxicol. Chem. 31, 115–121 (2012).

  58. 58.

    Montano, M. D., Badiei, H. R., Bazargan, S. & Ranville, J. F. Improvements in the detection and characterization of engineered nanoparticles using spICP-MS with microsecond dwell times. Environ. Sci. Nano 1, 338–346 (2014).

  59. 59.

    Montano, M. D., Olesik, J. W., Barber, A. G., Challis, K. & Ranville, J. F. Single particle ICP-MS: Advances toward routine analysis of nanomaterials. Anal. Bioanal. Chem. 408, 5053–5074 (2016).

  60. 60.

    Venkatesan, A. K. et al. Detection and sizing of Ti-containing particles in recreational waters using single particle ICP-MS. Bull. Environ. Contam. Toxicol. 100, 120–126 (2018).

  61. 61.

    Peters, R. J. B. et al. Detection of nanoparticles in Dutch surface waters. Sci. Total Environ. 621, 210–218 (2018).

  62. 62.

    Reed, R. B. et al. Multi-day diurnal measurements of Ti-containing nanoparticle and organic sunscreen chemical release during recreational use of a natural surface water. Environ. Sci. Nano 4, 69–77 (2017).

  63. 63.

    Linnik, P. N. & Zhezherya, V. A. Titanium in natural surface waters: The content and coexisting forms. Russ. J. Gen. Chem. 85, 2908–2920 (2015).

  64. 64.

    Nowack, B. et al. Progress towards the validation of modeled environmental concentrations of engineered nanomaterials by analytical measurements. Environ. Sci. Nano 2, 421–428 (2015).

  65. 65.

    Dale, A. L., Lowry, G. V. & Casman, E. A. Stream dynamics and chemical transformations control the environmental fate of silver and zinc oxide nanoparticles in a watershed-scale model. Environ. Sci. Technol. 49, 7285–7293 (2015).

  66. 66.

    Domercq, P., Praetorius, A. & Boxall, A. B. A. Emission and fate modelling framework for engineered nanoparticles in urban aquatic systems at high spatial and temporal resolution. Environ. Sci. Nano 5, 533–543 (2018).

  67. 67.

    Praetorius, A., Scheringer, M. & Hungerbuhler, K. Development of environmental fate models for engineered nanoparticles — A case study of TiO2 nanoparticles in the Rhine river. Environ. Sci. Technol. 46, 6705–6713 (2012).

  68. 68.

    Rice, J., Via, S. & Westerhoff, P. Extent and impacts of unplanned wastewater reuse in U.S. rivers. J. Am. Water Works Ass. 107, E571–E581 (2015).

  69. 69.

    Crittenden, J., Trussell, R., Hand, D., Howe, K. & Tchobanoglous, G. Water Treatment: Principles and Design 2nd edn (Wiley, Hoboken, NJ, 2005).

  70. 70.

    Westerhoff, P. in Nanotechnologies for Water Environment Applications Vol. 978-0-7844-1030-1 (eds Zhang, T. C. et al.) 630 (American Society of Civil Engineers, Reston, VA, 2009).

  71. 71.

    Park, C. M. et al. Occurrence and removal of engineered nanoparticles in drinking water treatment and wastewater treatment processes. Sep. Purif. Rev. 46, 255–272 (2017).

  72. 72.

    Chalew, T. E. A., Ajmani, G. S., Huang, H. O. & Schwab, K. J. Evaluating nanoparticle breakthrough during drinking water treatment. Environ. Health Perspect. 121, 1161–1166 (2013).

  73. 73.

    Chang, H. H., Cheng, T. J., Huang, C. P. & Wang, G. S. Characterization of titanium dioxide nanoparticle removal in simulated drinking water treatment processes. Sci. Total Environ. 601, 886–894 (2017).

  74. 74.

    Donovan, A. R. et al. Fate of nanoparticles during alum and ferric coagulation monitored using single particle ICP-MS. Chemosphere 195, 531–541 (2018).

  75. 75.

    Zhang, C. P. et al. Bench-scale study on the removal of TiO2 nanoparticles in natural lake water by coagulation. Chem. Lett. 46, 1846–1848 (2017).

  76. 76.

    Olabarrieta, J., Monzon, O., Belaustegui, Y., Alvarez, J. I. & Zorita, S. Removal of TiO2 nanoparticles from water by low pressure pilot plant filtration. Sci. Total Environ. 618, 551–560 (2018).

  77. 77.

    Donovan, A. R. et al. Single particle ICP-MS characterization of titanium dioxide, silver, and gold nanoparticles during drinking water treatment. Chemosphere 144, 148–153 (2016).

  78. 78.

    Yang, Y. & Westerhoff, P. in Nanomaterial: Impacts on Cell Biology and Medicine Vol. 811 (eds Capco, D. G. & Chen, Y.) 1–17 (Springer, Berlin, 2014).

  79. 79.

    Holbrook, R. D. et al. Titanium distribution in swimming pool water is dominated by dissolved species. Environ. Pollut. 181, 68–74 (2013).

  80. 80.

    Kirkegaard, P., Hansen, S. F. & Rygaard, M. Potential exposure and treatment efficiency of nanoparticles in water supplies based on wastewater reclamation. Environ. Sci. Nano 2, 191–202 (2015).

  81. 81.

    Yang, Y., Colman, B. P., Bernhardt, E. S. & Hochella, M. F. Importance of a nanoscience approach in the understanding of major aqueous contamination scenarios: Case study from a recent coal ash spill. Environ. Sci. Technol. 49, 3375–3382 (2015).

  82. 82.

    Hammes, F. A. & Egli, T. New method for assimilable organic carbon determination using flow-cytometric enumeration and a natural microbial consortium as inoculum. Environ. Sci. Technol. 39, 3289–3294 (2005).

  83. 83.

    Wang, Y. Y., Hammes, F., Duggelin, M. & Egli, T. Influence of size, shape, and flexibility on bacterial passage through micropore membrane filters. Environ. Sci. Technol. 42, 6749–6754 (2008).

  84. 84.

    Rice, E. W., Baird, R. B., Eaton, A. D. & Clesceri, L. S. Standard Methods for the Examination of Water And Wastewater. 22nd edn (American Public Health Association, Washington, DC, 2012).

  85. 85.

    Puls, R. W. & Powell, R. M. Acquisition of representative ground-water quality samples for metals. Ground Water Monit. Remed 12, 167–176 (1992).

  86. 86.

    Erickson, H. P. Size and shape of protein molecules at the nanometer level determined by sedimentation, gel filtration, and electron microscopy. Biol. Proc. Online 11, 32–51 (2009).

  87. 87.

    Logan, B. E., Grossart, H. P. & Simon, M. Direct observation of phytoplankton, TEP and aggregates on polycarbonate filters using brightfield microscopy. J. Plankton Res. 16, 1811–1815 (1994).

  88. 88.

    Her, N., Amy, G., Chung, J., Yoon, J. & Yoon, Y. Characterizing dissolved organic matter and evaluating associated nanofiltration membrane fouling. Chemosphere 70, 495–502 (2008).

  89. 89.

    Her, N. et al. Optimization of method for detecting and characterizing NOM by HPLC-size exclusion chromatography with UV and on-line DOC detection. Environ. Sci. Technol. 36, 1069–1076 (2002).

  90. 90.

    Efstratiou, A., Ongerth, J. & Karanis, P. Evolution of monitoring for Giardia and Cryptosporidium in water. Water Res. 123, 96–112 (2017).

  91. 91.

    Broadwell, M. A Practical Guide: Particle Counting for Drinking Water Treatment. (Lewis Publishers, Boca Raton, FL, 2001).

  92. 92.

    O’Leary, K. C., Eisnor, J. D. & Gagnon, G. A. Examination of plant performance and filter ripening with particle counters at full-scale water treatment plants. Environ. Technol. 24, 1–9 (2003).

  93. 93.

    Persson, F. et al. Characterisation of the behaviour of particles in biofilters for pre-treatment of drinking water. Water Res. 39, 3791–3800 (2005).

  94. 94.

    Webber, J. S. & Covey, J. R. Asbestos in water. Crit. Rev. Env. Contr. 21, 331–371 (1991).

  95. 95.

    Browne, M. L., Varadarajulu, D., Lewis-Michl, E. L. & Fitzgerald, E. F. Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980–1998. Environ. Res. 98, 224–232 (2005).

  96. 96.

    Guo, L. Y., Yuan, W. Y., Lu, Z. S. & Li, C. M. Polymer/nanosilver composite coatings for antibacterial applications. Colloid Surf. A 439, 69–83 (2013).

  97. 97.

    Walter, R. K., Lin, P. H., Edwards, M. & Richardson, R. E. Investigation of factors affecting the accumulation of vinyl chloride in polyvinyl chloride piping used in drinking water distribution systems. Water Res. 45, 2607–2615 (2011).

  98. 98.

    Edwards, M., Ferguson, J. F. & Reiber, S. H. The pitting corrosion of copper. J. Am. Water Works Ass. 86, 74–90 (1994).

  99. 99.

    McNeill, L. S. & Edwards, M. Iron pipe corrosion in distribution systems. J. Am. Water Works Ass. 93, 88–100 (2001).

  100. 100.

    Pieper, K. J., Tang, M. & Edwards, M. A. Flint water crisis caused by interrupted corrosion control: Investigating ‘ground zero’ home. Environ. Sci. Technol. 51, 2007–2014 (2017).

  101. 101.

    Triantafyllidou, S., Parks, J. & Edwards, M. Lead particles in potable water. J. Am. Water Works Ass. 99, 107–117 (2007).

  102. 102.

    Masters, S., Welter, G. J. & Edwards, M. Seasonal variations in lead release to potable water. Environ. Sci. Technol. 50, 5269–5277 (2016).

  103. 103.

    Edwards, M., Triantafyllidou, S. & Best, D. Elevated blood lead in young children due to lead-contaminated drinking water: Washington, DC, 2001–2004. Environ. Sci. Technol. 43, 1618–1623 (2009).

  104. 104.

    Bi, X. Y. et al. Quantitative resolution of nanoparticle sizes using single particle inductively coupled plasma mass spectrometry with the K-means clustering algorithm. J. Anal. At. Spectrom. 29, 1630–1639 (2014).

  105. 105.

    Gurian, P. L. & Small, M. J. Point-of-use treatment and the revised arsenic MCL. J. Am. Water Works Ass. 94, 101–108 (2002).

  106. 106.

    Sacchetti, R., De Luca, G., Guberti, E. & Zanetti, F. Quality of drinking water treated at point of use in residential healthcare facilities for the elderly. Int. J. Env. Res. Pub. He. 12, 11163–11177 (2015).

  107. 107.

    Slotnick, M. J., Meliker, J. R. & Nriagu, J. O. Effects of time and point-of-use devices on arsenic levels in Southeastern Michigan drinking water, USA. Sci. Total Environ. 369, 42–50 (2006).

  108. 108.

    Sublet, R., Simonnot, M. O., Boireau, A. & Sardin, M. Selection of an adsorbent for lead removal from drinking water by a point-of-use treatment device. Water Res. 37, 4904–4912 (2003).

  109. 109.

    Upadhyayula, V. K. K., Deng, S. G., Mitchell, M. C. & Smith, G. B. Application of carbon nanotube technology for removal of contaminants in drinking water: A review. Sci. Total Environ. 408, 1–13 (2009).

  110. 110.

    Bielefeldt, A. R., Kowalski, K. & Summers, R. S. Bacterial treatment effectiveness of point-of-use ceramic water filters. Water Res. 43, 3559–3565 (2009).

  111. 111.

    Ehdaie, B., Krause, C. & Smith, J. A. Porous ceramic tablet embedded with silver nanopatches for low-cost point-of-use water purification. Environ. Sci. Technol. 48, 13901–13908 (2014).

  112. 112.

    Loo, S. L. et al. Superabsorbent cryogels decorated with silver nanoparticles as a novel water technology for point-of-use disinfection. Environ. Sci. Technol. 47, 9363–9371 (2013).

  113. 113.

    Tomboulian, P., Schweitzer, L., Mullin, K., Wilson, J. & Khiari, D. Materials used in drinking water distribution systems: contribution to taste-and-odor. Water Sci. Technol. 49, 219–226 (2004).

  114. 114.

    van Genderen, J. & Hegarty, B. F. Approval testing of membrane water treatment systems. Desalination 117, 95–105 (1998).

  115. 115.

    Secondary Drinking Water Standards: Guidance for Nuisance Chemicals (USEPA, accessed 11 April 2018); https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals

  116. 116.

    Zimmerman, S. Flux Performance and Silver Leaching from In-Situ Synthesized Silver Nanoparticle Treated Reverse Osmosis Point of Use Membranes. MSc thesis, Arizona State Univ. (2017).

  117. 117.

    Ben-Sasson, M., Lu, X. L., Nejati, S., Jaramillo, H. & Elimelech, M. In situ surface functionalization of reverse osmosis membranes with biocidal copper nanoparticles. Desalination 388, 1–8 (2016).

  118. 118.

    Sile-Yuksel, M., Tas, B., Koseoglu-Imer, D. Y. & Koyuncu, I. Effect of silver nanoparticle (AgNP) location in nanocomposite membrane matrix fabricated with different polymer type on antibacterial mechanism. Desalination 347, 120–130 (2014).

  119. 119.

    Diagne, F. et al. Polyelectrolyte and silver nanoparticle modification of microfiltration membranes to mitigate organic and bacterial fouling. Environ. Sci. Technol. 46, 4025–4033 (2012).

  120. 120.

    Huang, L. C. et al. In situ immobilization of silver nanoparticles for improving permeability, antifouling and anti-bacterial properties of ultrafiltration membrane. J. Membr. Sci. 499, 269–281 (2016).

  121. 121.

    Mauter, M. S. et al. Antifouling ultrafiltration membranes via post-fabrication grafting of biocidal nanomaterials. ACS Appl. Mater. Interf. 3, 2861–2868 (2011).

  122. 122.

    Zodrow, K. R. et al. Advanced materials, technologies, and complex systems analyses: Emerging opportunities to enhance urban water security. Environ. Sci. Technol. 51, 10274–10281 (2017).

  123. 123.

    Notter, D. A., Mitrano, D. M. & Nowack, B. Are nanosized or dissolved metals more toxic in the environment? A meta-analysis. Environ. Toxicol. Chem. 33, 2733–2739 (2014).

  124. 124.

    Wijnhoven, S. W. P. et al. Nano-silver — A review of available data and knowledge gaps in human and environmental risk assessment. Nanotoxicology 3, 109–138 (2009).

  125. 125.

    Garner, K. L., Suh, S., Lenihan, H. S. & Keller, A. A. Species sensitivity distributions for engineered nanomaterials. Environ. Sci. Technol. 49, 5753–5759 (2015).

  126. 126.

    doReidy, B., Haase, A., Luch, A., Dawson, K. A. & Lynch, I. Mechanisms of silver nanoparticle release, transformation and toxicity: A critical review of current knowledge and recommendations for future studies and applications. Materials 6, 2295–2350 (2013).

  127. 127.

    McShan, D., Ray, P. C. & Yu, H. T. Molecular toxicity mechanism of nanosilver. J. Food Drug Anal. 22, 116–127 (2014).

  128. 128.

    Bondarenko, O. et al. Toxicity of Ag, CuO and ZnO nanoparticles to selected environmentally relevant test organisms and mammalian cells in vitro: A critical review. Arch. Toxicol. 87, 1181–1200 (2013).

  129. 129.

    Yada, R. Y. et al. Engineered nanoscale food ingredients: Evaluation of current knowledge on material characteristics relevant to uptake from the gastrointestinal tract. Compr. Rev. Food Sci. F. 13, 730–744 (2014).

  130. 130.

    Weir, A., Westerhoff, P., Fabricius, L., Hristovski, K. & von Goetz, N. Titanium dioxide nanoparticles in food and personal care products. Environ. Sci. Technol. 46, 2242–2250 (2012).

  131. 131.

    Yang, Y. et al. Characterization of food-grade titanium dioxide: The presence of nanosized particles. Environ. Sci. Technol. 48, 6391–6400 (2014).

  132. 132.

    Yang, Y. et al. Survey of food-grade silica dioxide nanomaterial occurrence, characterization, human gut impacts and fate across its lifecycle. Sci. Total Environ. 565, 902–912 (2015).

  133. 133.

    Shi, H. B., Magaye, R., Castranova, V. & Zhao, J. S. Titanium dioxide nanoparticles: A review of current toxicological data. Part. Fibre Toxicol. https://doi.org/10.1186/1743-8977-10-15 (2013).

  134. 134.

    Cao, Y. et al. Consideration of interaction between nanoparticles and food components for the safety assessment of nanoparticles following oral exposure: A review. Environ. Toxicol. Phar. 46, 206–210 (2016).

  135. 135.

    McClements, D. J. et al. The role of the food matrix and gastrointestinal tract in the assessment of biological properties of ingested engineered nanomaterials (iENMs): State of the science and knowledge gaps. NanoImpact 3–4, 47–57 (2016).

  136. 136.

    Warheit, D. B., Brown, S. C. & Donner, E. M. Acute and subchronic oral toxicity studies in rats with nanoscale and pigment grade titanium dioxide particles. Food Chem. Toxicol. 84, 208–224 (2015).

  137. 137.

    Brun, E. et al. Titanium dioxide nanoparticle impact and translocation through ex vivo, in vivo and in vitro gut epithelia. Part. Fibre Toxicol. https://doi.org/10.1186/1743-8977-11-13 (2014).

  138. 138.

    Mercier-Bonin, M., Despax, B., Raynaud, P., Houdeau, E. & Thomas, M. Mucus and microbiota as emerging players in gut nanotoxicology: The example of dietary silver and titanium dioxide nanoparticles. Crit. Rev. Food Sci. Nutr. 58, 1023–1032 (2018).

  139. 139.

    Kiser, M. A., Ladner, D., Hristovski, K. D. & Westerhoff, P. Nanomaterial transformation and association with fresh and freeze-dried wastewater activated sludge: Implications for testing protocol and environmental fate. Environ. Sci. Technol. 46, 7046–7053 (2012).

  140. 140.

    Westerhoff, P. K., Kiser, A. & Hristovski, K. Nanomaterial removal and transformation during biological wastewater treatment. Environ. Eng. Sci. 30, 109–117 (2013).

  141. 141.

    Westerhoff, P., Alvarez, P., Li, Q. & Gardea-Torresdey, J. Overcoming implementation barriers for nanotechnology in drinking water treatment. Environ. Sci. Nano 3, 1241–1253 (2016).

  142. 142.

    Tarantini, A. et al. Toxicity, genotoxicity and proinflammatory effects of amorphous nanosilica in the human intestinal Caco-2 cell line. Toxicol. Vitr. 29, 398–407 (2015).

  143. 143.

    Hem, J. Study and Interpretation of the Chemical Characteristics of Natural Water 3rd edn, 263 (US Geological Society, Washington, DC, 1992).

  144. 144.

    Yang, Y. et al. Discovery and ramifications of incidental Magneli phase generation and release from industrial coal-burning. Nat. Commun. 8, 11 (2017).

  145. 145.

    Schoepf, J. J. et al. Detection and dissolution of needle-like hydroxyapatite nanomaterials in infant formula. NanoImpact 5, 22–28 (2017).

  146. 146.

    Dietrich, A. M. & Burlingame, G. A. Critical review and rethinking of USEPA secondary standards for maintaining organoleptic quality of drinking water. Environ. Sci. Technol. 49, 708–720 (2015).

  147. 147.

    Alaszewski, A. Drugs, risk and society: Government, governance or governmentality? Health Risk Soc. 13, 389–396 (2011).

  148. 148.

    Debroux, J. F., Soller, J. A., Plumlee, M. H. & Kennedy, L. J. Human health risk assessment of non-regulated xenobiotics in recycled water: A review. Hum. Ecol. Risk Assess. 18, 517–546 (2012).

  149. 149.

    Ragain, L. Risk communication and media coverage of emerging contaminants. J. Am. Water Works Ass. 101, 100–105 (2009).

  150. 150.

    Ranville, J. & Montano, M. D. in Frontiers of Nanoscience Vol. 8 (eds Baalousha, M. A. & Lead, J. R.) 91–121 (Elsevier, New York, 2015).

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This work was partially funded by the National Science Foundation through the Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (EEC-1449500 and CBET-1336542). Partial funding was also provided from the USEPA through the STAR program (RD83558001). Jose Hernandez-Viezcas (University of Texas, El Paso) provided suggestions on optical sensing for ENPs, graphical assistance was provided by Michael Northrop (Arizona State University) and Laurel Passantino (Arizona State University) provided technical editing.

Author information


  1. Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA

    • Paul Westerhoff
    •  & Ariel Atkinson
  2. Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA

    • John Fortner
  3. Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, Department of Chemical Engineering, Rice University, Houston, TX, USA

    • Michael S. Wong
  4. Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA

    • Julie Zimmerman
  5. Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, Department of Chemistry, University of Texas – El Paso, El Paso, TX, USA

    • Jorge Gardea-Torresdey
  6. Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, USA

    • James Ranville
  7. School of Molecular Sciences, Arizona State University, Tempe, AZ, USA

    • Pierre Herckes


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The authors declare no competing interests.

Corresponding author

Correspondence to Paul Westerhoff.

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