Principles of Sound Ecotoxicology

The proliferation of silver nanoparticle (AgNP) production and use owing to their antimicrobial properties justifies the need to examine the resulting environmental impacts. The discharge of biocidal nanoparticles to water bodies may pose a threat to aquatic species. This study evaluated the effects of citrate-coated AgNPs on the standardized test organism Daphnia magna Straus clone MBP996 by means of biochemical biomarker response. AgNP toxicity was compared against the toxic effect of Ag(+). The toxicity endpoints were calculated based upon measured Ag concentrations in exposure media. For AgNPs, the NOAEC and LOAEC values at 48 h were 5 and 7 μg Ag/L, respectively, while these values were 0.5 and 1 μg Ag/L, respectively, for Ag(+). The EC50 at 48 h was computed to be 12.4 ± 0.6 and 2.6 ± 0.1 μg Ag/L for AgNPs and Ag(+), respectively, with 95 % confidence intervals of 12.1-12.8 and 2.3-2.8 μg Ag/L, respectively. These results indicate significant less toxicity of AgNP compared to free Ag(+) ions. Five biomarkers were evaluated in Daphnia magna neonates after acute exposure to Ag(+) or AgNPs, including glutathione (GSH) level, reactive oxygen species (ROS) content, and catalase (CAT), acetylcholinesterase (AChE), and superoxide dismutase (SOD) activity. AgNPs induced toxicity and oxidative stress responses in D. magna neonates at tenfold higher concentrations than Ag. Biochemical methods revealed a clear increase in AChE activity, decreased ROS level, increased GSH level and CAT activity, but no significant changes in SOD activity. As Ag(+) may dissolve from AgNPs, these two types of Ag could act synergistically and produce a greater toxic response. The observed remarkably high toxicity of AgNPs (in the parts-per-billion range) to crustaceans indicates that these organisms are a vulnerable link in the aquatic food chain with regard to contamination by nanosilver. Graphical Abstract ᅟ.

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“…Reporting In Vivo Experiments (ARRIVE) guidelines (Kilkenny et al 2010) and ecotoxicological principles proposed by Harris et al (2014).…”

Section: Responsible Editor: Thomas Hutchinsonmentioning

confidence: 99%

Response of biochemical biomarkers in the aquatic crustacean Daphnia magna exposed to silver nanoparticles

Ulm

Krivohlavek

Jurašin

et al. 2015

Environ Sci Pollut Res

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“…Any component-based study that explores whether CA and/or IA apply for a given mixture inherently assumes that the concentration-response curves of all individual substances are reproducible per se, which also has been discussed as a hallmark for 'sound ecotoxicology' [71]. Unfortunately, almost none of the studies analysed for this review provides information on the reproducibility of the experimental study results.…”

Section: Knowledge Gaps and The Next Stepsmentioning

confidence: 99%

Medicines, shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures

Backhaus

2014

Phil. Trans. R. Soc. B

118

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Analytical monitoring surveys routinely confirm that organisms in the environment are exposed to complex multi-component pharmaceutical mixtures. We are hence tasked with the challenge to take this into consideration when investigating the ecotoxicology of pharmaceuticals. This review first provides a brief overview of the fundamental approaches for mixture toxicity assessment, which is then followed by a critical review on the empirical evidence that is currently at hand on the ecotoxicology of pharmaceutical mixtures. It is concluded that, while the classical concepts of concentration addition and independent action (response addition) provide a robust scientific footing, several knowledge gaps remain. This includes, in particular, the need for more and better empirical data on the effects of pharmaceutical mixtures on soil organisms as well as marine flora and fauna, and exploring the quantitative consequences of toxicokinetic, toxicodynamic and ecological interactions. Increased focus should be put on investigating the ecotoxicology of pharmaceutical mixtures in environmentally realistic settings.

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“…Harris et al [10] noted both that the "cost of confirming or refuting the results of a poorly designed study can be extremely high" and that "inaccurate data may mean attention is not focused on the chemicals that are really of environmental concern." They recommend, as do we, both considering the concentrationresponse (or dose-response) and repeating key studies "to verify their conclusions."…”

Section: Discussionmentioning

confidence: 99%

Critical predicted no effect concentrations (PNECs) should not be based on a single toxicity test

Chapman

Elphick

2015

Enviro Toxic and Chemistry

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Predicted no-effect concentrations (PNECs), which represent the concentration of a substance below which an unacceptable effect most likely will not occur, are widely used for risk assessment and in environmental policy and regulation. They are typically based on single-species laboratory toxicity tests; often, a single test result for the most sensitive endpoints drives the derivation of a PNEC. In the present study, the authors provide a case study emphasizing the importance of determining the reliability of those most sensitive endpoints. Five 21-d Daphnia magna toxicity tests conducted using the same procedures by 2 laboratories gave 20% inhibitory concentration responses to a specific ionic composition of total dissolved solids that varied from 684 mg/L to more than 1510 mg/L. The concentration-response curve was shallow; thus, these differences could have been attributable to chance alone. The authors strongly recommend that the most sensitive endpoints that determine PNECs not be based on a single toxicity test result but rather on the geometric mean of at least 3 test results to adequately assess and bound test variability, especially when the concentration-response curve is shallow.

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Principles of Sound Ecotoxicology

Abstract: The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. 1 Principles of Sound Ecotoxicology

Cited by 140 publications

References 79 publications

Response of biochemical biomarkers in the aquatic crustacean Daphnia magna exposed to silver nanoparticles

Response of biochemical biomarkers in the aquatic crustacean Daphnia magna exposed to silver nanoparticles

Medicines, shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures

Critical predicted no effect concentrations (PNECs) should not be based on a single toxicity test

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