Critical Reviews in Environmental Science and Technology, 45:277–318, 2015 Copyright © Taylor & Francis Group, LLC ISSN: 1064-3389 print / 1547-6537 online DOI: 10.1080/10643389.2013.852407 Sources, Distribution, Environmental Fate, and Ecological Effects of Nanomaterials in Wastewater Streams ANITHA KUNHIKRISHNAN, 1 HO KYONG SHON, 2,3 NANTHI S. BOLAN, 3,4 IBRAHIM EL SALIBY, 2 and SARAVANAMUTHU VIGNESWARAN 2 1 Chemical Safety Division, Department of Agro-Food Safety, National Academy of Agricultural Science, Wanju-gun, Jeollabuk-do, Republic of Korea 2 School of Civil and Environmental Engineering, University of Technology, Sydney, Australia 3 Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Adelaide, Australia 4 Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, Australia Engineered nanomaterials (ENM) are manufactured, as opposed to being an incidental by-product of combustion or a natural process, and they often have unique or novel properties that emerge from their small size. These materials are being used in an expanding ar- ray of consumer products and, like all technological developments, have both benefits and risks. As the use of ENM in consumer prod- ucts becomes more common, the amount of these nanomaterials entering wastewater stream increases. Estimates of nanomaterials production are in the range of 500 and 50,000 tons per year for silver and titanium dioxide (TiO 2 ) alone, respectively. Nanoma- terials enter the wastewater stream during the production, usage, and disposal of nanomaterial-containing products. The predicted values of nanomaterials range from 0.003 (fullerenes) to 21 ng L -1 (nano-TiO 2 ) for surface waters, and from 4 ng L -1 (fullerenes) to 4 μgL -1 (nano-TiO 2 ) for sewage treatment effluents. Therefore, investigating the fate of nanomaterials in wastewater streams is critical for risk assessment and pollution control. The authors aim Address correspondence to Nanthi S. Bolan, Cooperative Research Centre for Contam- ination Assessment and Remediation of the Environment, Adelaide, Australia 5095. E-mail: Nanthi.Bolan@unisa.edu.au Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/best. 277