Food web effects of titanium dioxide nanoparticles in an outdoor freshwater mesocosm experiment

Abstract

Over the course of 78 days, nine outdoor mesocosms, each with 1350 L capacity, were situated on a pontoon platform in the middle of a lake and exposed to 0 μg L(-1) TiO2, 25 μg L(-1) TiO2 or 250 μg L(-1) TiO2 nanoparticles in the form of E171 TiO2 human food additive five times a week. Mesocosms were inoculated with sediment, phytoplankton, zooplankton, macroinvertebrates, macrophytes and fish before exposure, ensuring a complete food web. Physicochemical parameters of the water, nutrient concentrations, and biomass of the taxa were monitored. Concentrations of 25 μg L(-1) TiO2 and 250 μg L(-1) TiO2 caused a reduction in available soluble reactive phosphorus in the mesocosms by 15 and 23%, respectively, but not in the amount of total phosphorus. The biomass of Rotifera was significantly reduced by 32 and 57% in the TiO2 25 μg L(-1) and TiO2 250 μg L(-1) treatments, respectively, when compared to the control; however, the biomass of the other monitored groups-Cladocera, Copepoda, phytoplankton, macrophytes, chironomids and fish-remained unaffected. In conclusion, environmentally relevant concentrations of TiO2 nanoparticles may negatively affect certain parameters and taxa of the freshwater lentic aquatic ecosystem. However, these negative effects are not significant enough to affect the overall function of the ecosystem, as there were no cascade effects leading to a major change in its trophic state or primary production.

The effects of a human food additive, titanium dioxide nanoparticles E171, on Drosophila melanogaster - a 20 generation dietary exposure experiment

“…The same stock suspension was used in order to provide a more reliable comparison between the previous and present experiments. Previously, we provided a comprehensive physico-chemical characterization of this particular batch of E171 55 . In summary, E171 is at least 99% pure, and has an anatase crystalline structure.…”

Effects of suspended micro- and nanoscale particles on zooplankton functional diversity of drainage system reservoirs at an open-pit mine

“…On the other hand, studies on the impact of nanoparticles focus mainly on their high bioactivity 17 , which is determined by the following relationship: smaller particles exhibit larger active surface area resulting in higher bioavailability, which ends up in increased toxicity 28,56 . Experiments demonstrated that the toxicity of nanoparticles of a specific chemical composition (usually artificially synthesized compounds) depends on the biology of the plankton species subjected to the toxicological tests and to the environment of the interactions 22,25,31 .…”

“…Their reactivity stems not only from the size of the active surface, but also from a substantially larger scale of impact 28,29 . Studies on the influence of nanoparticles upon planktonic invertebrates were carried out with toxicology tests and referred mostly to Cladocera species 22,25,30,31 . Unfortunately, there are no similar studies on zooplankton in natural environment.…”

Histopathology of Chironomus riparius (Diptera, Chironomidae) exposed to metal oxide nanoparticles

“…The material was in the form of commercial white food coloring (E171) with 99% purity. Detailed characteristics of the nanoparticles were stated in two previous studies that used the same nanomaterial batch [13,37]. Nano-CeO2 with particles <25 nm in diameter were obtained from Sigma Aldrich, USA.…”