Review Interactions of carbon nanotubes with aqueous/aquatic media containing organic/inorganic contaminants and selected organisms of aquatic ecosystems – A review Sławomir Boncel a,⇑ , Joanna Kyzioł-Komosin ´ ska b , Iwona Krzy _ zewska b , Justyna Czupioł b a Silesian University of Technology, Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Krzywoustego 4, 44-100 Gliwice, Poland b Institute of Environmental Engineering, Polish Academy of Sciences, Marii Sklodowskiej-Curie 34, 41-819 Zabrze, Poland highlights  CNTs as a potential environmental contaminant – qualitative/quantitative review.  CNTs revealed as more powerful adsorbents of aromatic compounds than metal cations.  Contaminated CNTs as Trojan horse for biological membranes and/or toxins storage.  Longer exposures to CNTs leading to higher toxicity against Daphnia magna.  SWCNTs found as more ecotoxic than MWCNTs and oxidized/functionalized MWCNTs. article info Article history: Received 3 September 2014 Received in revised form 23 April 2015 Accepted 28 April 2015 Keywords: Carbon nanotubes Adsorption Heavy metal cations Aromatic organic compounds Aquatic microorganisms Environmental fate and toxicity abstract Due to their unique molecular architecture translating into numerous every-day applications, carbon nanotubes (CNTs) will be ultimately an increasingly significant environmental contaminant. This work reviews qualitative/quantitative analyses of interactions of various types of CNTs and their chemically modified analogues with aqueous/aquatic media containing organic and inorganic contaminants and selected organisms of aquatic ecosystems. A special emphasis was placed on physicochemical interac- tions between CNTs as adsorbents of heavy metal cations and aromatic compounds (dyes) with its envi- ronmental consequences. The studies revealed CNTs as more powerful adsorbents of aromatic compounds (an order of magnitude higher adsorption capacity) than metal cations. Depending on the presence of natural organic matter (NOM) and/or co-contaminants, CNTs may act as Trojan horse while passing through biological membranes (in the absence of NOM coordinating metal ions). Nanotubes, depending on flow conditions and their morphology/surface chemistry, may travel with natural waters or sediment with immobilized PAHs or metals and/or increase cyto- and ecotoxicity of PAHs/metal ions by their release via competitive complexation, or cause synergic ecotoxicity while adsorbing nutrients. Additionally, toxicity of CNTs against exemplary aquatic microorganisms was reviewed. It was found for Daphnia magna that longer exposures to CNTs led to higher ecotoxicity with a prolonged CNTs excre- tion. SWCNTs were more toxic than MWCNTs, while hydrophilization of CNTs via oxidation or anchoring thereto polar/positively charged polymer chains enhanced stability of nanotubes dispersion in aqueous media. On the other hand, bioavailability of functionalized CNTs was improved leading to more complex both mechanisms of uptake and cytotoxic effects. Ó 2015 Elsevier Ltd. All rights reserved. Contents 1. Introduction ......................................................................................................... 212 2. Interactions of CNTs with water environment elements ...................................................................... 212 3. Adsorption of heavy metal ions and aromatic compounds on CNTs from aqueous media ........................................... 215 http://dx.doi.org/10.1016/j.chemosphere.2015.04.095 0045-6535/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: slawomir.boncel@polsl.pl (S. Boncel). Chemosphere 136 (2015) 211–221 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere