Biomagnification of cadmium selenide quantum dots in a simple experimental microbial food chain

Abstract

Previous studies have shown that engineered nanomaterials can be transferred from prey to predator, but the ecological impacts of this are mostly unknown. In particular, it is not known if these materials can be biomagnified-a process in which higher concentrations of materials accumulate in organisms higher up in the food chain. Here, we show that bare CdSe quantum dots that have accumulated in Pseudomonas aeruginosa bacteria can be transferred to and biomagnified in the Tetrahymena thermophila protozoa that prey on the bacteria. Cadmium concentrations in the protozoa predator were approximately five times higher than their bacterial prey. Quantum-dot-treated bacteria were differentially toxic to the protozoa, in that they inhibited their own digestion in the protozoan food vacuoles. Because the protozoa did not lyse, largely intact quantum dots remain available to higher trophic levels. The observed biomagnification from bacterial prey is significant because bacteria are at the base of environmental food webs. Our findings illustrate the potential for biomagnification as an ecological impact of nanomaterials.

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

“…Conceptually, CdSe QDs [36] can dissolve externally to cells or can enter cells either intact after damaging membranes or accumulate in cells as highly reactive toxicants [37]. If QDs remain intact, they are subject to trophic transfer and possible biomagnification in their predators [38]. Assigning toxicity to either dissolved or intact nanoparticulate phases is an important endeavor, because it may influence the future safe design of ENPs.…”

“…1, pp. [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]2012 # 2011 SETAC Printed in the USA DOI: 10.1002/etc.723 This paper evolved from discussions held at a SETAC-endorsed Technical Workshop held at Clemson University in August, 2010. The workshop was sponsored by the United States Environmental Protection Agency (U.S. EPA), Arcadis-US, and the Clemson University Institute of Environmental Toxicology.…”

Research Trends of Food Chain Transfer of Nanomaterials in Freshwater and Marine Ecosystems

“…해양생태계에서의 나노물질 영양단계전이 연구는 지금까 지 약 5편 정도가 발표되었으며( Table 2) Lewinski et al, 2011;Cedervall et al, 2012 (Plankton-Water flea-Fish) (C) Lee and An, 2014 (ProtozoaWater flea-Fish) (a) Werlin et al, 2011;Mielke et al, 2013 (Bacteria-Protozoa) (b) Croteau et al, 2011 (Diatom-Snail) (c) Bouldin et al, 2008;Dalai et al, 2014;Gilroy et al, 2014;McTeer et al, 2014;Pakrashi et al, 2014 (Plankton- …”

Photovoltaic Conversion: Outlook at the Crossroads Between Technological Challenges and Eco-Strategic Issues

“…Technologies using cadmium telluride (CdTe) generate some controversy for two main reasons: a) the presence of cadmium (Cd), a metal classified as a group 1 carcinogen by the International Agency for Research on Cancer (IARC, 1997) and b) little documentation exists about the extent of their particularly chronic potential toxicity (Norwegian Geotechnical Institute [NGI], 2010). These concerns also include emerging CdTe and CdSe-based solar nanotechnologies (Peyrot et al, 2009;Werlin et al, 2011). The other element worth considering is the limited number of manufacturers using CdTe, which limits the scope of studies based mainly on data supplied by the manufacturers.…”

“…The emerging technologies require just as much vigilance as a result of the shortage of current ecotoxicological data, which would invite more refined investigations in the future in order to keep up with the growing dynamics of the market. The cadmium-based PV industry is specifically concerned since the current data seems to indicate that CdTe nanoparticles have the potential of bioaccumulation in aquatic organisms (Peyrot et al, www.intechopen.com (Werlin et al, 2011). Overall, there is a consensus that the evaluations performed to date seem to give the PV industry much more credit than fossil fuels, but the fragmentary nature of the results indicate that more in-depth investigation is required.…”