Ecotoxicology https://doi.org/10.1007/s10646-018-1959-8 Toxicity and uptake of nanoparticulate and bulk ZnO in nematodes with different life strategies Krisztina Hrács 1 ● Zoltán Sávoly 2 ● Anikó Seres 1 ● Lola Virág Kiss 1 ● Ibolya Zita Papp 3 ● Ákos Kukovecz 3 ● Gyula Záray 4 ● Péter Nagy 1 Accepted: 20 June 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract Despite the increasing number and quantity of nanomaterials released in the environment, our knowledge on their bioavailability and possible toxicity to organisms is rather limited. Thus, we know quite little about sensitivity of various nematode feeding types and life strategies to treatments with nano metal oxides. The toxicity of zinc oxide nanoparticles (nano-ZnO) (with a particle size of 25 nm) and the bulk counterpart was investigated in two free-living nematode species of different life strategies: Xiphinema vuittenezi, a K-strategist plant-feeder nematode and Panagrellus redivivus, an r-strategist bacterivor nematode. The internal zinc concentration and the concentration of minor and trace elements were determined by total reflection X-ray fluorescence spectrometry. Concentration-dependent mortality in both nematode species was observed following a 24-h exposure both to nano-ZnO and bulk ZnO. The zinc concentration of the treating suspension had a significant effect on the internal zinc content of the animals in both cases. Particle size did not influence the internal zinc content. Our results show that nano and bulk ZnO have a similar dose-response effect on mortality of the bacterivor P. redivivus. In contrast, the nano-ZnO has stronger toxic effect on the mortality of X. vuittenezi. In general, X. vuittenezi did not react more sensitively to the treatments than P. redivivus, but appeared sensitive to the nano-ZnO treatment compared to bulk ZnO. Keywords ZnO nanoparticles ● TXRF ● Free-living nematodes ● Ecotoxicology Introduction Nanotechnology industry is a rapidly developing segment of the world market and its importance is growing in many areas (UNESCO, Science Report 2015). Engineered nanoparticles have a potential to be used in a wide range of products due to their specific properties (Aitken et al. 2006) caused by the high surface area per volume ratio and the fact that most of the atoms are located close to the surface (Casals et al. 2012). While the number of products manu- factured using nanotechnology is increasing, their bioa- vailability to organisms and possible toxicity are usually unknown (De Jong and Borm 2008). ZnO nanoparticles are used in various technological applications as a consequence of their specific properties. Due to their high catalytic activity, ZnO nanoparticles are used in ceramics, cement, glass, paint and in many consumer products (Song et al. 2010). Because of their effective UV light-absorbing capacity, ZnO nanoparticles are also applied in sunsc- reens and in other related cosmetic products (Serpone et al. 2007). The increased release of nano-ZnO into the environment may cause intensified risk (Dumont et al. 2015). That is why improving the understanding of the fate and toxicity of nano-ZnO in the environment is an urgent task. Conse- quently, ecotoxicological studies were performed in water as well as soil environment. Several studies have investi- gated the effect of ZnO nanoparticles and their bulk coun- terpart to aquatic (Blinova et al. 2010; Heinlaan et al. 2008;) * Krisztina Hrács hracskriszti@gmail.com 1 Department of Zoology and Animal Ecology, Szent István University, Páter Károly u. 1., Gödöllo H-2100, Hungary 2 Independent researcher, Budapest, Hungary 3 Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1., Szeged H-6720, Hungary 4 Danube Research Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Karolina út 29., Budapest H- 1113, Hungary 1234567890();,: 1234567890();,: