Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna

The production and use of nanoparticles (NP) has steadily increased within the last decade; however, knowledge about risks of NP to human health and ecosystems is still scarce. Common knowledge concerning NP effects on freshwater organisms is largely limited to standard short-term (≤48 h) toxicity t...

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Main Authors:	Dabrunz, André, Duester, Lars, Prasse, Carsten, Seitz, Frank, Rosenfeldt, Ricki, Schilde, Carsten, Schaumann, Gabriele E., Schulz, Ralf
Format:	Online
Language:	English
Published:	Public Library of Science 2011
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3103543/

id	pubmed-3103543
recordtype	oai_dc
spelling	pubmed-31035432011-06-06 Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna Dabrunz, André Duester, Lars Prasse, Carsten Seitz, Frank Rosenfeldt, Ricki Schilde, Carsten Schaumann, Gabriele E. Schulz, Ralf Research Article The production and use of nanoparticles (NP) has steadily increased within the last decade; however, knowledge about risks of NP to human health and ecosystems is still scarce. Common knowledge concerning NP effects on freshwater organisms is largely limited to standard short-term (≤48 h) toxicity tests, which lack both NP fate characterization and an understanding of the mechanisms underlying toxicity. Employing slightly longer exposure times (72 to 96 h), we found that suspensions of nanosized (∼100 nm initial mean diameter) titanium dioxide (nTiO2) led to toxicity in Daphnia magna at nominal concentrations of 3.8 (72-h EC50) and 0.73 mg/L (96-h EC50). However, nTiO2 disappeared quickly from the ISO-medium water phase, resulting in toxicity levels as low as 0.24 mg/L (96-h EC50) based on measured concentrations. Moreover, we showed that nTiO2 (∼100 nm) is significantly more toxic than non-nanosized TiO2 (∼200 nm) prepared from the same stock suspension. Most importantly, we hypothesized a mechanistic chain of events for nTiO2 toxicity in D. magna that involves the coating of the organism surface with nTiO2 combined with a molting disruption. Neonate D. magna (≤6 h) exposed to 2 mg/L nTiO2 exhibited a “biological surface coating” that disappeared within 36 h, during which the first molting was successfully managed by 100% of the exposed organisms. Continued exposure up to 96 h led to a renewed formation of the surface coating and significantly reduced the molting rate to 10%, resulting in 90% mortality. Because coating of aquatic organisms by manmade NP might be ubiquitous in nature, this form of physical NP toxicity might result in widespread negative impacts on environmental health. Public Library of Science 2011-05-27 /pmc/articles/PMC3103543/ /pubmed/21647422 http://dx.doi.org/10.1371/journal.pone.0020112 Text en Dabrunz et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Dabrunz, André Duester, Lars Prasse, Carsten Seitz, Frank Rosenfeldt, Ricki Schilde, Carsten Schaumann, Gabriele E. Schulz, Ralf
spellingShingle	Dabrunz, André Duester, Lars Prasse, Carsten Seitz, Frank Rosenfeldt, Ricki Schilde, Carsten Schaumann, Gabriele E. Schulz, Ralf Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna
author_facet	Dabrunz, André Duester, Lars Prasse, Carsten Seitz, Frank Rosenfeldt, Ricki Schilde, Carsten Schaumann, Gabriele E. Schulz, Ralf
author_sort	Dabrunz, André
title	Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna
title_short	Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna
title_full	Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna
title_fullStr	Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna
title_full_unstemmed	Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna
title_sort	biological surface coating and molting inhibition as mechanisms of tio2 nanoparticle toxicity in daphnia magna
description	The production and use of nanoparticles (NP) has steadily increased within the last decade; however, knowledge about risks of NP to human health and ecosystems is still scarce. Common knowledge concerning NP effects on freshwater organisms is largely limited to standard short-term (≤48 h) toxicity tests, which lack both NP fate characterization and an understanding of the mechanisms underlying toxicity. Employing slightly longer exposure times (72 to 96 h), we found that suspensions of nanosized (∼100 nm initial mean diameter) titanium dioxide (nTiO2) led to toxicity in Daphnia magna at nominal concentrations of 3.8 (72-h EC50) and 0.73 mg/L (96-h EC50). However, nTiO2 disappeared quickly from the ISO-medium water phase, resulting in toxicity levels as low as 0.24 mg/L (96-h EC50) based on measured concentrations. Moreover, we showed that nTiO2 (∼100 nm) is significantly more toxic than non-nanosized TiO2 (∼200 nm) prepared from the same stock suspension. Most importantly, we hypothesized a mechanistic chain of events for nTiO2 toxicity in D. magna that involves the coating of the organism surface with nTiO2 combined with a molting disruption. Neonate D. magna (≤6 h) exposed to 2 mg/L nTiO2 exhibited a “biological surface coating” that disappeared within 36 h, during which the first molting was successfully managed by 100% of the exposed organisms. Continued exposure up to 96 h led to a renewed formation of the surface coating and significantly reduced the molting rate to 10%, resulting in 90% mortality. Because coating of aquatic organisms by manmade NP might be ubiquitous in nature, this form of physical NP toxicity might result in widespread negative impacts on environmental health.
publisher	Public Library of Science
publishDate	2011
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3103543/
_version_	1611456279569498112

Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna

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