Low risk posed by engineered and incidental nanoparticles in drinking water


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.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Distribution of particle sizes and number concentrations reported in surface, ocean and ground waters.
Fig. 2: Time-resolved 49Ti data for Verde River (left), and tap water from a DWTP treating Verde River water (right).
Fig. 3: ENP predicted surface water concentrations, background bulk concentrations, detection limits and drinking water standards.
Fig. 4


  1. 1.

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

    Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    CAS  Google Scholar 

  6. 6.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  12. 12.

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

    CAS  Article  Google Scholar 

  13. 13.

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

    CAS  Article  Google Scholar 

  14. 14.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  17. 17.

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

    CAS  Article  Google Scholar 

  18. 18.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  Google Scholar 

  21. 21.

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

    Article  Google Scholar 

  22. 22.

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

    CAS  Article  Google Scholar 

  23. 23.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  35. 35.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  47. 47.

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

    CAS  Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  51. 51.

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

    CAS  Article  Google Scholar 

  52. 52.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  55. 55.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  61. 61.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  90. 90.

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

    CAS  Article  Google Scholar 

  91. 91.

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

    Google Scholar 

  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).

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  94. 94.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  98. 98.

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

    CAS  Article  Google Scholar 

  99. 99.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  101. 101.

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

    CAS  Article  Google Scholar 

  102. 102.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  114. 114.

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

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  127. 127.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  131. 131.

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

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  140. 140.

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

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  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).

    Article  CAS  Google Scholar 

  145. 145.

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

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  147. 147.

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

    Article  Google Scholar 

  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).

    CAS  Article  Google Scholar 

  149. 149.

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

    CAS  Article  Google Scholar 

  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).

Download references


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



Corresponding author

Correspondence to Paul Westerhoff.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Westerhoff, P., Atkinson, A., Fortner, J. et al. Low risk posed by engineered and incidental nanoparticles in drinking water. Nature Nanotech 13, 661–669 (2018). https://doi.org/10.1038/s41565-018-0217-9

Download citation

Further reading