Critical comparison of intravenous injection of TiO2 nanoparticles with waterborne and dietary exposures concludes minimal environmentally-relevant toxicity in juvenile rainbow trout Oncorhynchus mykiss

Abstract

A critical comparison of studies that have investigated tissue accumulation and toxicity of TiO2-NPs in fish is necessary to resolve inconsistencies. The present study used identical TiO2-NPs, toxicological endpoints, and fish (juvenile rainbow trout Oncorhynchus mykiss) as previous studies that investigated waterborne and dietary toxicity of TiO2-NPs, and conducted a critical comparison of results after intravenous caudal-vein injection of 50 μg of TiO2-NPs and bulk TiO2. Injected TiO2-NPs accumulated only in kidney (94% of measured Ti) and to a lesser extent in spleen; and injected bulk TiO2 was found only in kidney. No toxicity of TiO2 was observed in kidney, spleen, or other tissues. Critical comparison of these data with previous studies indicates that dietary and waterborne exposures to TiO2-NPs do not lead to Ti accumulation in internal tissues, and previous reports of minor toxicity are inconsistent or attributable to respiratory distress resulting from gill occlusion during waterborne exposure.

Chronic exposure of tilapia (Oreochromis niloticus) to iron oxide nanoparticles: Effects of particle morphology on accumulation, elimination, hematology and immune responses

“…In water-borne exposure to bulk and nanoTiO 2 , Ti levels were much higher in spleen of rainbow trout than in kidney (Boyle et al, 2013a), but kidney contained about 10-fold higher Ti (ca. 300 μg/g) than spleen in intravenous exposure where aggregation was substantial in the saline blood plasma (Boyle et al, 2013b). Accumulation in spleen was also faster compared with other organs (Ramsden et al, 2009).…”

“…Extensive accumulation from exposure to NPs of Ag, TiO 2 , CuO, and ZnO has been reported on the gills of fish (Zhao et al, 2011; Boyle et al, 2013a, 2013b; Hao et al, 2013; Imani et al, 2014; Ates et al, 2015). Because NP aggregates are too large to penetrate into gill tissue, the accumulation is ascribed to adsorption/adhesion of NPs on the gill epithelial surfaces to varying degrees as determined by NP type, concentration and exposure time (Kaya et al, 2015).…”

Sex specific response in cholesterol level in zebrafish ( Danio rerio ) after long-term exposure of difenoconazole

“…Fish are an important eco-indicator organism and many model species, such as rainbow trout (Oncorhynchus mykiss), medaka (Oryzias latipes) and zebrafish, have been applied in the toxicity evaluation of environmental pollutants (Boyle et al, 2013;Gonz alez-Doncel et al, 2014;Zhang et al, 2013). The zebrafish (Danio rerio) is a typical small tropical aquarium fish well known to most people.…”

Interactions between suspension characteristics and physicochemical properties of silver and copper oxide nanoparticles: A case study for optimizing nanoparticle stock suspensions using a central composite design

“…However, the complexity of sonication makes it difficult to compare different studies using sonication to disperse nanoparticles. For example, sonication times which are directly related to the energy delivered to a solution during sonication vary considerably from as little as a few minutes (Buffet et al, 2011;Zhou et al, 2012) to as much as an hour or more (Boyle et al, 2013;vanAerle et al, 2013). As suggested by Taurozzi et al (2011), the inconsistent application of sonication is a potential source of variability in the properties of suspensions, and probably contributes to the lack of consistency in results across laboratories and between operators.…”