Identifier

etd-04072014-221010

Degree

Master of Science in Biological and Agricultural Engineering (MSBAE)

Department

Biological and Agricultural Engineering

Document Type

Thesis

Abstract

Nanotechnology has become integrated in commercial, industrial and medical products, and its use has grown exponentially in the past several years. Although potential applications of nanoparticles (NPs) are numerous, concerns about their water quality, environmental, and human health impacts remain unclear. Crayfish are ubiquitous to streams and wetland habitats, are used as a food source, and inhabit areas that could be impacted by water quality issues. Numerous studies have been conducted on the toxicity of various classes of agricultural pesticides and oils to crayfish (Procambarus clarkii) as a non-target organism. However, there is little evidence published on chronic toxicity of NP to crayfish. The first objective of this study was to estimate the 28 day toxicity and bioaccumulation of the three most produced nanoparticles, Ag, ZnO, and TiO2, in a laboratory adult crayfish model. The organisms were exposed to different Ag, ZnO, and TiO2 nanoparticle solutions at concentrations of 0, 100, 500, and 1000 𝜇g/mL. AgNO3 and KNO3, and Zn(NO3)2•6H2O and KNO3 were used as bulk controls for Ag and ZnO treatments, respectively. Dead crayfish were removed and preserved then examined for metal accumulation and pathological changes in behavior. Metal accumulation in major organs was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Results indicate that as the concentration of NP increases the uptake of metal in tissue also increases. In this case, the chemical rankings of toxicity are as follows: AgNO₃ > Zn(NO₃)₂ > AgNP > ZnO > KNO₃ > TiO₂. Silver accumulated in gill tissue 3 times more in AgNO3 treatments than in AgNP treatments. In abdominal tissue, silver accumulated 4 times more in AgNO3 treatments than in AgNP treatments. Zinc accumulated in gill tissue 2 times more in Zn(NO₃)₂ treatments than in ZnO treatments. The second objective was to estimate the bioaccumulation of the nanoparticles: Ag, ZnO, and TiO2 in a mesocosm adult crayfish model. From previous experiments, we determined the following concentrations for each tank: AgNPs 20 mg/L, ZnO 50 mg/L, and TiO2 100 mg/L. A 0 mg/L control tank was also used. Three crayfish were removed from each tank and preserved for analysis weekly. Soil samples were taken bi-weekly. ICP-OES was used to look at the accumulation of the metals in the gill and abdominal tissues as well as the soil samples. Results indicate that bioaccumulation occurs in tissues in fluctuating trend rather than an increasing trend.

Date

2014

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Hall, Steven G.

Included in

Engineering Commons

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