ISSN 1995-0780, Nanotechnologies in Russia, 2012, Vol. 7, Nos. 9–10, pp. 509–516. © Pleiades Publishing, Ltd., 2012. Original Russian Text © A.A. Gusev, I.A. Fedorova, A.G. Tkachev, A.Yu. Godymchuk, D.V. Kuznetsov, I.A. Polyakova, 2012, published in Rossiiskie Nanotekhnologii, 2012, Vol. 7, Nos. 9–10. 509 INTRODUCTION Since the early 1990s, the development, manufac- ture, and introduction of carbon nanostructured materials have been the most rapidly growing branch of nanotechnologies [1]. In particular, carbon nano- tubes (CNTs) are promising for obtaining ultrastrong threads and composite materials, transistors and fuel cells, capsules for the storage of metals and gases, high-selective molecular sieves, display devices, and light-emitting diodes [2]. They are also used in target- ing pharmaceuticals and the production of biomateri- als and biosensors [3]. Therefore, the safety of this class of nanomaterials in regards to labor and health have come to the fore [4] and investigating the toxic action of carbon nanomaterials (CNMs) is among the most urgent tasks of toxicology and environmental toxicology [5]. The number of publications on nanoparticle toxi- cology has been exponentially growing within the last six years [6, 7]. Because CNMs are produced in greater amounts than any other nanomaterial, numer- ous studies are focused on their toxic action, migra- tion, and entry into the environment. Many authors demonstrate the high stability of nanotubes in the environment. For example, CNTs can form stable aerosols in disposal by incineration [8]. They are also resistant to degradation in soil [9]. These are prerequisites for their migration to the hydrosphere followed by absorption or adhesion by living organisms. After entry to the hydrosphere with sewage or pol- luted air, engineered nanoparticles first enter aquatic organisms: zoo- and phytoplankton, fishes, benthic invertebrates, etc. These organisms are the bases of food webs, which makes them the most probable site for the primary accumulation of all fine abiogenic pol- lutants, including nanoparticles [10]. Single- or multiwalled CNTs can enter the alimen- tary tract of aquatic invertebrates and accumulate there [11]. They cause disorders in hydrosphere inhab- itants [12] and delay embryonic development [13]. Fullerene C60 adhesion to crustacean bodies (para- sites Acartia tonsa) has been reported to disturb their behavior and physiology [14]. The factors conjectured to determine the toxicity of CNTs include heavy-metal penetration [15], the mechanical breakdown of physical barriers in cells and cell membranes (membrane stress) [16, 17], the cata- lytic and inhibitory action of nanomaterials on bio- chemical processes [17], and free radical formation [9, 18, 19]. Little information on the cytogenetic action of CNMs is available. An analysis of the mitotic index (MI), chromosomal aberrations, micronuclei, and DNA Acute Toxic and Cytogenetic Effects of Carbon Nanotubes on Aquatic Organisms and Bacteria A. A. Gusev a , I. A. Fedorova b , A. G. Tkachev c , A. Yu. Godymchuk d , D. V. Kuznetsov e , and I. A. Polyakova a a Derzhavin State University, Medical Institute, ul. Sovetskaya 93, Tambov, 392000 Russia b National Research Center Chernyshevskii State University, ul. Astrakhanskaya 83, Saratov, 410012 Russia c NanoTekhTsentr, ul. Sovetskaya 51, Tambov, 392000 Russia d Tomsk Polytechnic University, pr. Lenina 30, Tomsk, 634050 Russia e National University of Science and Technology “MISiS,” podr. 217, Leninskii pr. 4, Moscow, 119049 Russia e-mail: nanosecurity@mail.ru Received December 21, 2011; accepted May 16, 2012 Abstract—This paper summarizes a comprehensive study concerning the acute toxicity of a commercial car- bon nanomaterial consisting mostly of carbon nanotubes to larvae of Chironomidae, crustaceans Ceriodaph- nia affinis, algae Scenedesmus quadricauda, and bacteria Escherichia coli. It is shown that the nucleolar orga- nizer region (NOR) index of polytene chromosomes in the salivary gland cells of midge larvae depends on the duration of concentration and exposure. This fact is indicative of the switching on of cell adaptation pathways in response to a xenobiotic stressor to restore cell homeostasis. The investigated nanomaterial is labeled as a Class III environmentally hazardous material (moderately hazardous). Safe concentrations of the carbon nanomaterial in aquatic media are less than 2 mg/l. It is concluded that larvae of Chironomidae are the most resistant to the material of all test species, whereas Scenedesmus quadricauda and Escherichia coli are the most sensitive. DOI: 10.1134/S1995078012050060