Acute and Developmental Toxicity of Metal Oxide Nanoparticles to Fish and Frogs
|Principal Investigator||Christopher Theodorakis|
|Institution||Southern Illinois University - Edwardsville|
|Relevance to Implications||High|
|Class of Nanomaterial||Engineered Nanomaterials|
|Broad Research Categories||
|Anticipated Total Funding||$375,000.00|
|Anticipated End Year||2008|
The objectives of this research are to determine the environmental hazard associated with selected metal oxide nanoparticles (Fe2O3, ZnO, CuO, and TiO2) in terms of acute and chronic toxicity to fathead minnows (Pimephase promelas) and the African clawed frog (Xenopus laevis). The hypotheses are that nanoparticle exposure will affect the survival, growth, development, egg hatchability, and metamorphosis of these organisms in a dose-dependent fashion, and differences in relative toxicity (LC50, EC50, NOEC, LOEC) of these nanoparticles coincide with the relative toxicity of their soluble salts or oxides.
Fathead minnows and frogs will be exposed to metal oxide nanoparticles during 96 hour acute toxicity and developmental toxicity tests. Chronic tests will include 28 day early life stage tests (starting with in 24 to post fertilization) for minnows and 10 week exposures (hatch until metamorphosis completion) for Xenopus. Endpoints will include survival, growth, percent hatch, developmental abnormalities, and rate of metamorphosis (for Xenopus). Acute toxicity (growth, survival) endpoints will be reported as LC50s, chronic toxicity endpoints will be reported as EC50s, NOECs and LOECs. Nanoparticles will be kept in suspension in the water using aeration- or peristaltic pump-induced water currents (i.e., minimizing settling of nanoparticles). Mixing of aged and fresh nanoparticles in test solutions will be minimized using flow-through systems. Physiochemical characterization of nanoparticles before and during tests will be carried out by atomic force and electron microscopic methods. Metal concentrations will be monitored in water and tissues by means of atomic absorption spectrophotometry. Nanoparticles will be synthesized chemically at Clemson University.
It is expected that the nanoparticles will increase mortality and developmental abnormalities in fish and frogs, and decrease growth rates, rates of metamorphosis, and hatchability. Calculation of LC50s and EC50s for acute and developmental toxicity is of benefit because these chemicals have the potential for widespread release into aquatic environments, either due to large scale manufacture or use or to applications in decontamination of ground water and waste streams. However, little, if anything, is known about their potential hazard in aquatic environments. The LC50s and EC50s would allow ecological risk assessment of these particles at an early stage in the development of this technology. It should be noted that, even if none of these nanoparticles show any affect on minnow or frog larvae, this would still be useful information.