Aquatic ecotoxicity effect of engineered aminoclay nanoparticles Moon-Hee Choi a,1 , Yuhoon Hwang b,1 , Hyun Uk Lee c , Bohwa Kim d , Go-Woon Lee e , You-Kwan Oh d , Henrik R. Andersen b , Young-Chul Lee f,g,n , Yun Suk Huh f a Department of Beauty and Cosmetology, Graduate School of Industry, Chosun University, Gwangju 501-759, Republic of Korea b Department of Environmental Engineering, Technical University of Denmark, Miljøvej, B113, DK-2800, Kgs. Lyngby, Denmark c Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333, Republic of Korea d Clean Fuel Department, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea e Testing and Certification Center, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea f Department of Biological Engineering, College of Engineering, Inha University, Incheon 402-751, Republic of Korea g Department of Civil and Environmental Engineering (BK21 program), KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea article info Article history: Received 2 September 2013 Received in revised form 4 January 2014 Accepted 8 January 2014 Keywords: Aminoclay Ecotoxicity Pseudokirchneriella subcapitata Daphnia magna Vibrio fischeri abstract In the present study the short term aquatic ecotoxicity of water-solubilized aminoclay nanoparticles (ANPs) of 51 731 nm average hydrodynamic diameter was characterized. An ecotoxicological evalua- tion was carried out utilizing standard test organisms of different phyla and trophic levels namely the eukaryotic microalga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the biolumi- nescent marine bacteria Vibrio fisheri. The effective inhibitory concentration (EC 50 ) with 95% confidence limits for the microalga was 1.29 mg/L (0.72–1.82) for the average growth rate and 0.26 mg/L (0.23–0.31) for the cell yield. The entrapping of algal cells in aggregates of ANP may play a major role in the growth inhibition of algae P. subcapitata. No inhibition was observed for V. fisheri up to 25,000 mg/L (no observed effect concentration; NOEC). For D. magna no immobilization was observed in a limit test with 100 mg/L in 24 h while in 48 h a single animal was immobilized (5% inhibition). Correspondingly, the NOEC of ANP in 24 h was 100 mg/L and the lowest observed effect concentration (LOEC) for 48 h was 100 mg/L. Therefore it can be considered to use ANP as an algal-inhibition agent at concentrations o100 mg/L without affecting or only mildly affecting other organisms including zooplanktons, but further studies on the environmental fate and chronic toxicity of ANP is needed to confirm this. & 2014 Elsevier Inc. All rights reserved. 1. Introduction Studies on the toxicity of engineered nanomaterials for biological systems and the environment are urgently required due to the limited availability or lack of data and knowledge (Grieger et al., 2012; Hansen et al., 2013a). The toxicity of nanoparticles (NPs, o100 nm) is believed to be associated with their physico-chemical characteristics (Fruijtier-Pollöth, 2012; Van Hoecke et al., 2008), which include size, shape, surface area/volume ratio, chemical composition, and surface chemistry, along with their generation of reactive oxygen species (ROS) as the result of reaction between oxygen and radiation (or light energy) activation (Nel et al., 2006; Lin et al., 2012; Oberdörster et al., 2006). Many NP ecotoxicity studies such as those involving fullerene (C 60 )(Oberdörster et al., 2006), carbon nanotubes (CNT) (Hu et al., 2011; Poland et al., 2008) and graphene (oxide) (Liao et al., 2011), quantum dots (Tortiglione et al., 2009; Holbrook et al., 2008), nanoparticles of TiO 2 (Lin et al., 2012; Hund-Rinke and Simon, 2006; Musee et al., 2011; Strigul et al., 2009), ZnO (Lowry et al., 2012), SiO 2 (Musee et al., 2011; Lowry et al., 2012; Fent et al., 2010), CeO 2 (García et al., 2011), surface-modified nanoscale zerovalent iron (nZVI) (Gondikas et al., 2012; Chen et al., 2012), transformations of silver (Ag) (Levard et al., 2012), and complex interaction with copper (Cu) NPs (Mudunkotuwa et al., 2012), and gold (Au) (Ferry et al., 2009) have been conducted, and still more toxicological investigations on aquatic organisms and mammalian cells are currently ongoing. However, many properties and phenomena in newly engineered NPs, and their regulation, remain to be addressed (Kim and Tanguay, 2013; Baun et al., 2008; Moore, 2006; Hansen et al., 2011, 2013b). In 1997, 3-aminopropyl functionalized magnesium phyllosili- cate (denoted aminoclay and abbreviated as ANP herein) was first developed. Several research groups have utilized the unique properties of the positively charged organo-building blocks ( o100 nm diameter by dynamic light scattering (DLS) (Mann et al., 1997) which are water-soluble and transparent in aqueous Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety 0147-6513/$ - see front matter & 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecoenv.2014.01.005 n Corresponding author at: Department of Civil and Environmental Engineering (BK21 program), KAIST, 291Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea. E-mail address: dreamdbs@kaist.ac.kr (Y.-C. Lee). 1 These authors equally contributed to this work. Ecotoxicology and Environmental Safety 102 (2014) 34–41