Dynamics of sub-lethal effects of nano-CuO on the microalga Chlamydomonas reinhardtii during short-term exposure.
Though nano-CuO has been classified as toxic toward aquatic microorganisms and its use in various applications is expected to increase in near future, its ecotoxicity is currently poorly understood. The aim of this study was to investigate the mechanisms of nano-CuO toxicity based on the paradigm of oxidative stress, the dynamics of response over 24h, and the modulating effect of exposure conditions on toxicity and responses. To this end, the model microalga Chlamydomonas reinhardtii was exposed to 10mgL(-1) nano-CuO in five different exposure media, including two different growth media, two Good's buffers, and natural lake water. The measured endpoints included cell growth, morphological aspect, chlorophyll autofluorescence, oxidative stress, and membrane permeabilization. The results suggest that agglomerated nano-CuO is toxic and that exposure media are decisive in whether or not particles or free Cu ions are the main mediators of toxicity. A significant particle effect was only observed in the Good's buffer 3-(N-morpholino) propanesulfonic acid. However, nano-CuO particles especially influenced the dynamics of response early in exposure, between 0h and 5h, suggesting that an adaptation to particle stress may occur or that particles modify the bioavailability of the free Cu ions in early exposure.
Environmental Biogeochemistry and Ecotoxicology, Earth and Environmental Science Section, Institute F.-A. Forel, University of Geneva, 10, Route de Suisse, CH-1290 Versoix, Switzerland.
Nadia
N
von Moos
Environmental Biogeochemistry and Ecotoxicology, Earth and Environmental Science Section, Institute F.-A. Forel, University of Geneva, 10, Route de Suisse, CH-1290 Versoix, Switzerland.
Luca
L
Maillard
Environmental Biogeochemistry and Ecotoxicology, Earth and Environmental Science Section, Institute F.-A. Forel, University of Geneva, 10, Route de Suisse, CH-1290 Versoix, Switzerland. Electronic address: vera.slaveykova@unige.ch.
Vera I
VI
Slaveykova
D016825:Chlamydomonas reinhardtii / Q000187:drug effects*; D002734:Chlorophyll / Q000378:metabolism; D003300:Copper / Q000633:toxicity*; D003470:Culture Media; D005618:Fresh Water; D018384:Oxidative Stress / Q000187:drug effects; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity
D003470:Culture Media; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D003300:Copper; C030973:cupric oxide
(Nano-)ecotoxicology; Aquatic microorganisms; Engineered nanoparticles; Flow cytometry; Reactive oxygen species