Tuesday, May 27, 2008
247

Aqueous toxicity and food chain transfer of fluorescent nanocrystals in freshwater algae and Ceriodaphnia dubia

Jennifer L. Bouldin1, Taylor M. Ingle2, Anindita Sengupta1, Regina Alexander3, Robyn E. Hannigan4, and Roger A. Buchanan2. (1) Ecotoxicology Research Facility, Arkansas State University, P.O. Box 847, State University, AR 72467, (2) Molecular Biosciences Program, Arkansas State University, P.O. Box 847, State University, AR 72467, (3) Department of Biological Sciences, Arkansas State University, P.O. Box 847, State University, AR 72467, (4) Environmental Sciences Program, Arkansas State University, P.O. Box 847, State University, AR 72467

Innovative research and diagnostic techniques for biological testing have advanced during recent years due to the development of semiconductor nanocrystals.  Although these commercially available fluorescent nanocrystals have a protective organic coating, the inner core contains cadmium and selenium.  Because these metals have the potential for detrimental environmental effects, concerns have been raised from the lack of understanding of the environmental fate of these products.  US EPA test protocol and fluorescence microscopy was used to determine the fate and effect of Quantum dots (QD® 545 ITK™ Carboxyl QDs) using standard aquatic test organisms.  Although no lethality was measured following 48-h exposure of Ceriodaphnia dubia to suspensions as high as 110 ppb, 96-h LC50 to Pseudokirchneriella subcapitata was measured at 37.1 ppb QDs.  Transfer of QDs from dosed algae to C. dubia was verified with fluorescence microscopy.  These results indicate that coatings present on nanocrystals provide protection from metal toxicity during laboratory exposures but the transfer of core metals from intact nanocrystals may occur at levels well above toxic threshold values indicating potential adverse effects at higher trophic levels.  Studies on the fate and effects of nanoparticles can be incorporated into models for predictive toxicology of these emerging contaminants. 


Web Page: Quantum dots, aqueous toxicity, food chain transfer

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