Organismal and cellular effects of nanomaterials in fish models


Key Findings for 2011:
-­‐ Data from our Tanguay collaboration showed no toxicity associated with C60,TiO2, CeO2, or the stabilizer controls. AgNP toxicity was significant, but lower than observed for AgNO3.
-­‐ The toxicity of water sampled from all AgNP dosed mesocosms was reduced compared to laboratory -­‐ prepared AgNP dosing solutions prepared in clean natural water at the same level of measured Ag for Fundulus heteroclitus and Danio rerio embryos yet increased for PVP coated NP for Fundulus heteroclitus hatchlings.
-­‐ The toxicity of water sampled from AgNO3 dosed mesocosms was lower for AgNPs than AgNO3 on an equal Ag mass basis for Fundulus heteroclitus hatchlings.
-­‐ Microcosm experiments performed to replicate the mesocosm experiments on a smaller level showed the same patterns of toxicity for Danio rerio but not for Fundulus heteroclitus.
-­‐ In this microcosm experiment, the presence of plants was shown to drive reduction in toxicity of AgNP to Danio rerio, Daphnia magna, and Fundulus heteroclitus.
-­‐ Dissolved organic carbon associated with the plants was shown to affect the stability, aggregation state, complexation, and speciation of AgNP.
-­‐ Gambusia holbrooki living in the mesocosms have been periodically sampled and found to have taken up substantial concentrations of Ag despite very low water concentrations.
-­‐ Gambusia holbrooki living in the prototype mesocosms have been found to have taken up substantial concentrations of Ag, and maternal transfer of Ag to embryos was confirmed.
-­‐ Sulfidation of AgNP reduces toxicity to Fundulus heteroclitus embryos.
-­‐ TiO2 exhibits substantial phototoxicity when using a solar simulator to perform exposures to Danio rerio hatchlings.
-­‐ Model organic matter (cysteine) substantially reduces fish embryotoxicity of AgNPs, but does not affect Ag uptake.
-­‐ Ag uptake on and in Fundulus embryos is significantly reduced at higher salinities, but toxicity is unaffected.
-­‐ Multiple lines of evidence documenting a disconnect between uptake and toxicity for AgNPs.
-­‐ Speciation of Ag (μXRF, XANES) in Fundulus embryos varies with NP coating and exposure media salinity.