title: An interlaboratory comparison of nanosilver characterisation and hazard identification: Harmonising techniques for high quality data.
abstract: Within the FP7 EU project NanoValid a consortium of six partners jointly investigated the hazard of silver nanoparticles (AgNPs) paying special attention to methodical aspects that are important for providing high-quality ecotoxicity data. Laboratories were supplied with the same original stock dispersion of AgNPs. All partners applied a harmonised procedure for storage and preparation of toxicity test suspensions. Altogether ten different toxicity assays with a range of environmentally relevant test species from different trophic levels were conducted in parallel to AgNP characterisation in the respective test media. The paper presents a comprehensive dataset of toxicity values and AgNP characteristics like hydrodynamic sizes of AgNP agglomerates and the share (%) of Ag(+)-species (the concentration of Ag(+)-species in relation to the total measured concentration of Ag). The studied AgNP preparation (20.4±6.8 nm primary size, mean total Ag concentration 41.14 mg/L, 46-68% of soluble Ag(+)-species in stock, 123.8±12.2 nm mean z-average value in dH2O) showed extreme toxicity to crustaceans Daphnia magna, algae Pseudokirchneriella subcapitata and zebrafish Danio rerio embryos (EC50<0.01 mg total Ag/L), was very toxic in the in vitro assay with rainbow trout Oncorhynchus mykiss gut cells (EC50: 0.01-1 mg total Ag/L); toxic to bacteria Vibrio fischeri, protozoa Tetrahymena thermophila (EC50: 1-10 mg total Ag/L) and harmful to marine crustaceans Artemia franciscana (EC50: 10-100 mg total Ag/L). Along with AgNPs, also the toxicity of AgNO3 was analyzed. The toxicity data revealed the same hazard ranking for AgNPs and AgNO3 (i.e. the EC50 values were in the same order of magnitude) proving the importance of soluble Ag(+)-species analysis for predicting the hazard of AgNPs. The study clearly points to the need for harmonised procedures for the characterisation of NMs. Harmonised procedures should consider: (i) measuring the AgNP properties like hydrodynamic size and metal ions species in each toxicity test medium at a range of concentrations, and (ii) including soluble metal salt control both in toxicity testing as well as in Ag(+)-species measurements. The present study is among the first nanomaterial interlaboratory comparison studies with the aim to improve the hazard identification testing protocols.
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Večna pot 111, 1000 Ljubljana, Slovenia. Electronic address: anita.jemec@bf.uni-lj.si.
authors.forename: Anita
authors.initials: A
authors.lastname: Jemec
authors.affiliation: National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Anne
authors.initials: A
authors.lastname: Kahru
authors.affiliation: Fraunhofer Institute for Ceramic Technologies and Systems, Winterbergstrasse 28, 01277 Dresden, Germany.
authors.forename: Annegret
authors.initials: A
authors.lastname: Potthoff
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Večna pot 111, 1000 Ljubljana, Slovenia.
authors.forename: Damjana
authors.initials: D
authors.lastname: Drobne
authors.affiliation: National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Margit
authors.initials: M
authors.lastname: Heinlaan
authors.affiliation: Helmholtz-Centre for Environmental Research - UFZ, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Steffi
authors.initials: S
authors.lastname: Böhme
authors.affiliation: Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133 Postfach 611, 8600 Dübendorf, Switzerland.
authors.forename: Mark
authors.initials: M
authors.lastname: Geppert
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Večna pot 111, 1000 Ljubljana, Slovenia.
authors.forename: Sara
authors.initials: S
authors.lastname: Novak
authors.affiliation: Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133 Postfach 611, 8600 Dübendorf, Switzerland.
authors.forename: Kristin
authors.initials: K
authors.lastname: Schirmer
authors.affiliation: Centre for Cellular & Molecular Biology, Habsiguda, Hyderabad, Telangana 500007, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Rekulapally
authors.affiliation: Centre for Cellular & Molecular Biology, Habsiguda, Hyderabad, Telangana 500007, India.
authors.forename: Shashi
authors.initials: S
authors.lastname: Singh
authors.affiliation: National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Villem
authors.initials: V
authors.lastname: Aruoja
authors.affiliation: National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Mariliis
authors.initials: M
authors.lastname: Sihtmäe
authors.affiliation: National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Katre
authors.initials: K
authors.lastname: Juganson
authors.affiliation: National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Käkinen
authors.affiliation: Helmholtz-Centre for Environmental Research - UFZ, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Dana
authors.initials: D
authors.lastname: Kühnel
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D000818:Animals; D001156:Artemia / Q000187:drug effects; D002460:Cell Line; D000460:Chlorophyta / Q000187:drug effects; D003621:Daphnia / Q000187:drug effects; D015386:Hazardous Substances / Q000633:toxicity*; D007753:Laboratories / Q000592:standards / Q000706:statistics & numerical data*; D053768:Metal Nanoparticles / Q000633:toxicity*; D017686:Oncorhynchus mykiss / Q000254:growth & development; D012834:Silver / Q000633:toxicity*; D016808:Tetrahymena thermophila / Q000187:drug effects; D018675:Toxicity Tests / Q000592:standards / Q000706:statistics & numerical data*; D015027:Zebrafish / Q000254:growth & development
chemical_list: D015386:Hazardous Substances; D012834:Silver
keywords: Ag salt; Dissolution; FP7 EU project NanoValid; Hydrodynamic diameter; Nanomaterials' aging; Toxicity