Multigeneration impacts on Daphnia magna of carbon nanomaterials with differing core structures and...

Several classes of contaminants have been shown to have multigenerational impacts once a parental generation has been exposed. Acute and chronic toxicity are described for several types of nanomaterials in the literature; however, no information is available on the impact of nanomaterials on future generations of organisms after the exposure is removed. In the present study, the authors examined the impacts of carbon nanomaterials (CNMs), including fullerenes (C60), single-walled carbon nanotubes (SWCNTs), and multiwalled carbon nanotubes (MWCNTs) with neutral, positive, and negative functional groups to F1 and F2 generation daphnids after an F0 exposure. Data from the present study indicate that multigenerational toxicity is present with certain nanomaterial exposures and is highly dependent on the surface chemistry of the nanomaterial. Many CNMs that showed toxicity to exposed F0 daphnids in previous experiments did not induce multigenerational toxicity. 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. Industries should take into account how surface chemistry influences nanomaterial toxicity to future generations of organisms to create sustainable nanomaterials that do not harm freshwater ecosystems.