Multilaboratory evaluation of 15 bioassays for (eco)toxicity screening and hazard ranking of engineered nanomaterials: FP7 project NANOVALID

Abstract

Within EU FP7 project NANOVALID, the (eco)toxicity of 7 well-characterized engineered nanomaterials (NMs) was evaluated by 15 bioassays in 4 laboratories. The highest tested nominal concentration of NMs was 100 mg/l. The panel of the bioassays yielded the following toxicity order: Ag > ZnO > CuO > TiO2 > MWCNTs > SiO2 > Au. Ag, ZnO and CuO proved very toxic in the majority of assays, assumingly due to dissolution. The latter was supported by the parallel analysis of the toxicity of respective soluble metal salts. The most sensitive tests/species were Daphnia magna (towards Ag NMs, 24-h EC50 = 0.003 mg Ag/l), algae Raphidocelis subcapitata (ZnO and CuO, 72-h EC50 = 0.14 mg Zn/l and 0.7 mg Cu/l, respectively) and murine fibroblasts BALB/3T3 (CuO, 48-h EC50 = 0.7 mg Cu/l). MWCNTs showed toxicity only towards rat alveolar macrophages (EC50 = 15.3 mg/l) assumingly due to high aspect ratio and TiO2 towards R. subcapitata (EC50 = 6.8 mg Ti/l) due to agglomeration of TiO2 and entrapment of algal cells. Finally, we constructed a decision tree to select the bioassays for hazard ranking of NMs. For NM testing, we recommend a multitrophic suite of 4 in vitro (eco)toxicity assays: 48-h D. magna immobilization (OECD202), 72-h R. subcapitata growth inhibition (OECD201), 30-min Vibrio fischeri bioluminescence inhibition (ISO2010) and 48-h murine fibroblast BALB/3T3 neutral red uptake in vitro (OECD129) representing crustaceans, algae, bacteria and mammalian cells, respectively. Notably, our results showed that these assays, standardized for toxicity evaluation of “regular” chemicals, proved efficient also for shortlisting of hazardous NMs. Additional assays are recommended for immunotoxicity evaluation of high aspect ratio NMs (such as MWCNTs).

Natural water as the test medium for Ag and CuO nanoparticle hazard evaluation: An interlaboratory case study

“…In literature, adult zebrafish have been shown to be highly sensitive to copper (48 h LC 50 of 0.25 mg Cu/L for CuSO 4 $5H 2 O and 48 h LC 50 of 1.56 mg nanocopper/L (Griffitt et al, 2007)). High copper toxicity in standard medium has also been reported for zebrafish embryos (OECD236) in a NP toxicity screening study within the NanoValid project: 96 h EC 50 of 1.6 mg Cu/L (95% CI 0.84e2.24 mg Cu/L) for CuO NNV-011 (Bondarenko et al, 2016). Hua et al (2014) also found Cu NPs highly toxic to zebrafish embryos with 120 h LC 50 for 25 nm Cu NPs 1.03 mg Cu NP/L (95% CI 0.85e1.25) and for Cu(NO 3 ) 2 0.70 mg Cu/L (95% CI 0.68e0.72).…”

“…CuO nanoparticles (CuO NNV-011, provider Intrinsiq Materials, nanoscaled powder with primary particle size of 22e25 nm) were in powder form. The initial (above-mentioned) NP characterization data are from the providers but the same type of Ag NPs have been previously characterized and described in Bondarenko et al, 2016;B€ ohme et al, 2015, Zou et al, 2015and CuO NPs in Bondarenko et al, 2016 (see SI, Table S1). As ionic controls, analytical grade metal salts AgNO 3 and CuSO 4 $5H 2 O were used.…”

“…In order to assess NP exposure and hazard under real-life scenarios, several case studies were performed within the project, the current of which dealt with the assessment of NP ecotoxicity under realistic conditions. Based on the results of an (eco)toxicity profiling battery (consisting of 15 test organisms/cells) (Bondarenko et al, 2016) but also on literature-based nanomaterial hazard evaluation suggestions Garner and Keller, 2014; IHCP/2011/I/05/ 27/OC), Ag and CuO NPs were chosen as model NPs for this interlaboratory environmental case study using natural freshwater as the test medium in comparison to the standard test media. For that, two different natural waters from two sampling campaigns from Swiss Lake Greifen and Lake Lucerne were used and NP properties in these waters were thoroughly characterized.…”

Effects of Nanoparticles on Algae: Adsorption, Distribution, Ecotoxicity and Fate

“…TiO 2 nanoparticles were also used as antibacterial agents and colorants in paints and food packaging [14,15], which were likely to then migrate into the environment or food sources and cause potential harm to organisms. In addition, nanoparticles in food can penetrate into the digestive tract lymphatic vessels, and compared with other large particles, can be more easily distributed into other tissues and organs [16].Organisms of different trophic levels are usually selected to assess the ecotoxicity of NPs, including primary producers (algae), consumers (mammals, crustaceans) and decomposers (microbes) [17]. Among them, algae are the most widely used to evaluate the ecotoxicity of NPs.…”

“…Organisms of different trophic levels are usually selected to assess the ecotoxicity of NPs, including primary producers (algae), consumers (mammals, crustaceans) and decomposers (microbes) [17]. Among them, algae are the most widely used to evaluate the ecotoxicity of NPs.…”