Abstract
In this study, the effects of aged Ag and TiO2
nanoparticles (NPs), individually and as a mixture, in wastewater
relative to their pristine counterparts on the development of the
copepod nauplii (Tisbe battagliai) were investigated. NP behavior in
synthetic wastewater and seawater was characterized during aging
and exposure. A delayed development and subsequent mortality
were observed after 6 days of exposure to aged Ag NPs, with a
twofold decrease in EC50 (316 μg/L) compared to pristine NPs
(EC50 640 μg/L) despite the similar dissolved Ag concentrations
measured for aged and pristine Ag NPs (441 and 378 μg/L,
respectively). In coexposures with TiO2 NPs, higher dissolved Ag
levels were measured for aged NPs (238.3 μg/L) relative to pristine
NPs (98.57 μg/L). Coexposure resulted in a slight decrease (15%)
in the Ag NP EC50 (270 μg/L) with a 1.9-fold increase in the Ag NP
retained within the organisms after depuration (2.82% retention) compared to Ag NP single exposures as measured with sp-ICP−
MS, suggesting that the particles are still bioavailable despite the heteroaggregation observed between Ag, Ti NPs, and wastewater
components. This study shows that the presence of TiO2 NPs can affect the stability and toxicity of Ag NPs in complex media that
cannot be predicted solely based on ionic, total, or nanoparticulate concentrations, and the need for studying NP interactions in
more complex matrices is highlighted.
nanoparticles (NPs), individually and as a mixture, in wastewater
relative to their pristine counterparts on the development of the
copepod nauplii (Tisbe battagliai) were investigated. NP behavior in
synthetic wastewater and seawater was characterized during aging
and exposure. A delayed development and subsequent mortality
were observed after 6 days of exposure to aged Ag NPs, with a
twofold decrease in EC50 (316 μg/L) compared to pristine NPs
(EC50 640 μg/L) despite the similar dissolved Ag concentrations
measured for aged and pristine Ag NPs (441 and 378 μg/L,
respectively). In coexposures with TiO2 NPs, higher dissolved Ag
levels were measured for aged NPs (238.3 μg/L) relative to pristine
NPs (98.57 μg/L). Coexposure resulted in a slight decrease (15%)
in the Ag NP EC50 (270 μg/L) with a 1.9-fold increase in the Ag NP
retained within the organisms after depuration (2.82% retention) compared to Ag NP single exposures as measured with sp-ICP−
MS, suggesting that the particles are still bioavailable despite the heteroaggregation observed between Ag, Ti NPs, and wastewater
components. This study shows that the presence of TiO2 NPs can affect the stability and toxicity of Ag NPs in complex media that
cannot be predicted solely based on ionic, total, or nanoparticulate concentrations, and the need for studying NP interactions in
more complex matrices is highlighted.