Multigeneration impacts on Daphnia magna of carbon nanomaterials with differing core structures and functionalizations.
Bottom Line: Several classes of contaminants have been shown to have multigenerational impacts once a parental generation has been exposed.Certain nanomaterials, however, such as C60-malonate, SWCNTs, SWCNT-CONH2 , and MWCNTs, caused a significant decrease in either survival or reproduction in F1 daphnids; and SWCNT-CONH2 decreased reproduction out to the F2 generation.Impacts of nanomaterials on F1 and F2 size were small and lacked clear patterns, indicating that CNMs have minimal multigenerational impacts on size.
Affiliation: School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA.Show MeSH
Related in: MedlinePlus
Mentions: Select CNMs did have an impact on reproduction up to 2 generations after parental exposure. Carbon nanomaterial core structure was an important parameter that influenced multigenerational reproduction in daphnids. Of the unfunctionalized CNMs, only 50 ppm SWCNTs significantly decreased F1 daphnid reproduction compared with controls (decrease of 23%, t = 2.767, p < 0.05; Figure 3A); but this effect was not observed in the F2 generation. At a concentration of 50 ppm, C60 reduced reproduction by 17% in F2 daphnids (t = −4.137, p < 0.05) (Figure 3B). Finally, 10 ppm and 50 ppm MWCNTs reduced reproduction in the F1 and F2 generations, but this was only significant for 10 ppm exposures in F2 (decrease of 18%, t = −2.192, p < 0.05; Figure 3A and B). The addition of COOH or PEG surface chemistry to SWCNTs did not change reproduction compared with controls in any generation; however, SWCNT-CONH2 significantly reduced reproduction in both F1 (decrease of 17%, t = −6.351, p < 0.05) and F2 (decrease of 17%, t = −3.956, p < 0.05) daphnids (Figure 4A and B), indicating that this surface chemistry increases the toxicity of SWCNTs to future generations of daphnids.
Affiliation: School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA.