Behavioral and Physiological Changes inDaphnia magnawhen Exposed to Nanoparticle Suspensions (Titanium Dioxide, Nano-C₆₀, and C₆₀HxC₇₀Hx)

Abstract

Little is known about the impact manufactured nanoparticles will have on aquatic organisms. Previously, we demonstrated that toxicity differs with nanoparticle type and preparation and observed behavioral changes upon exposure to the more lethal nanoparticle suspensions. In this experiment, we quantified these behavioral and physiological responses of Daphnia at sublethal nanoparticle concentrations. Titanium dioxide (TiO 2 ) and fullerenes (nano-C 60 ) were chosen for their potential use in technology. Other studies suggest that addition of functional groups to particles can affect their toxicity to cell cultures, but it is unknown if the same is true at the whole organism level. Therefore, a fullerene derivative, C 60 HxC 70 Hx, was also used to examine how functional groups affect Daphnia response. Using a high-speed camera, we quantified several behavior and physiological parameters including hopping frequency, feeding appendage and postabdominal curling movement, and heart rate. Nano-C 60 was the only suspension to cause a significant change in heart rate. Both exposure to nano-C 60 and C 60 HxC 70 Hx suspensions caused hopping frequency and appendage movement to increase. These results are associated with increased risk of predation and reproductive decline. They indicate that certain nanoparticle types may have impacts on population and food web dynamics in aquatic systems.

Methodological considerations for testing the ecotoxicity of carbon nanotubes and fullerenes: Review

“…Evidence exists that surface chemistry can influence toxicity in test organisms, including Ceriodaphnia dubia [61], in which alkyl and amino functional groups on CNTs dramatically increased toxicity, whereas hydrophilic groups made the CNTs less toxic. Likewise, various types of surface-modified fullerenes have also exhibited substantially different toxicities to Daphnia pulex and Daphnia magna compared with underivatized fullerenes [62,63]. It was shown previously that cellular toxicity varies substantially based on surface coatings or functional groups on the surfaces of CNTs [64,65].…”

The potential health risk of titania nanoparticles

“…TNP toxicity has been observed in diverse models, such as rodents [15][16][17][18], aquatic organisms [19][20][21], and human cells [22][23][24]. Female workers were reported to experience shortness of breath and pleural effusions after 5-13 months of exposure in a polyacrylic ester nanoparticle processing factory [25], raising significant doubt about the human safety of TNPs.…”

Instrumental approach toward understanding nano-pollutants

“…In fact, aggregates will tend to be removed from the water by sedimentation, increasing the concentration of NPs in sediment and increasing exposure of benthic organisms [94]. Lovern et al [86] also showed that the rapid dilution, the distribution and the suspensions of NPLTs in aquatic systems might have consequences on organisms, such as Daphnia magna ( Table 2). The measurement of NPs in environmental media involves significant challenges because their concentrations must be determined through a mixture of anthropic and anthropogenic NPs, with different compositions and varied particle sizes [100].…”