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Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna.

Asghari S, Johari SA, Lee JH, Kim YS, Jeon YB, Choi HJ, Moon MC, Yu IJ - J Nanobiotechnology (2012)

Bottom Line: Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared.All the silver species in this study caused abnormal swimming by the D. magna.According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered.

View Article: PubMed Central - HTML - PubMed

Affiliation: Young Researchers Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.

ABSTRACT

Background: To better understand the potential ecotoxicological impacts of silver nanoparticles released into freshwater environments, the Daphnia magna 48-hour immobilization test was used.

Methods: The toxicities of silver nitrate, two types of colloidal silver nanoparticles, and a suspension of silver nanoparticles were assessed and compared using standard OECD guidelines. Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared. The particle suspension and colloids used in the toxicity tests were well-characterized.

Results: The results obtained from the exposure studies showed that the toxicity of all the silver species tested was dose and composition dependent. Plus, the silver nanoparticle powders subsequently suspended in the exposure water were much less toxic than the previously prepared silver nanoparticle colloids, whereas the colloidal silver nanoparticles and AgNO(3) were almost similar in terms of mortality. The silver nanoparticles were ingested by the Daphnia and accumulated under the carapace, on the external body surface, and connected to the appendages. All the silver species in this study caused abnormal swimming by the D. magna.

Conclusion: According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered.

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UV-VIS absorption spectra for colloids of nAg1 and nAg2, nAg3 suspension, and AgNO3 solution.
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Figure 5: UV-VIS absorption spectra for colloids of nAg1 and nAg2, nAg3 suspension, and AgNO3 solution.

Mentions: In the spectral scans of the nAg1 and nAg2 colloids, a strong surface plasmon resonance was centered at approximately 420 and 410 nm, respectively (Figure 5), which is similar to previous results for AgNPs [5,19-21]. However, for the nAg3 suspension, AgNO3 solution, and distilled water, no distinct peaks were observed (Figure 5). The observation of a strong surface plasmon peak has already been well documented for various metal nanoparticles, with sizes ranging from 2 to 100 nm [22,23]. In the case of nAg3, the increase in the particle size to more than 100 nm through aggregation may have been the reason for the lack of appearance of a distinct peak.


Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna.

Asghari S, Johari SA, Lee JH, Kim YS, Jeon YB, Choi HJ, Moon MC, Yu IJ - J Nanobiotechnology (2012)

UV-VIS absorption spectra for colloids of nAg1 and nAg2, nAg3 suspension, and AgNO3 solution.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3344683&req=5

Figure 5: UV-VIS absorption spectra for colloids of nAg1 and nAg2, nAg3 suspension, and AgNO3 solution.
Mentions: In the spectral scans of the nAg1 and nAg2 colloids, a strong surface plasmon resonance was centered at approximately 420 and 410 nm, respectively (Figure 5), which is similar to previous results for AgNPs [5,19-21]. However, for the nAg3 suspension, AgNO3 solution, and distilled water, no distinct peaks were observed (Figure 5). The observation of a strong surface plasmon peak has already been well documented for various metal nanoparticles, with sizes ranging from 2 to 100 nm [22,23]. In the case of nAg3, the increase in the particle size to more than 100 nm through aggregation may have been the reason for the lack of appearance of a distinct peak.

Bottom Line: Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared.All the silver species in this study caused abnormal swimming by the D. magna.According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered.

View Article: PubMed Central - HTML - PubMed

Affiliation: Young Researchers Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.

ABSTRACT

Background: To better understand the potential ecotoxicological impacts of silver nanoparticles released into freshwater environments, the Daphnia magna 48-hour immobilization test was used.

Methods: The toxicities of silver nitrate, two types of colloidal silver nanoparticles, and a suspension of silver nanoparticles were assessed and compared using standard OECD guidelines. Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared. The particle suspension and colloids used in the toxicity tests were well-characterized.

Results: The results obtained from the exposure studies showed that the toxicity of all the silver species tested was dose and composition dependent. Plus, the silver nanoparticle powders subsequently suspended in the exposure water were much less toxic than the previously prepared silver nanoparticle colloids, whereas the colloidal silver nanoparticles and AgNO(3) were almost similar in terms of mortality. The silver nanoparticles were ingested by the Daphnia and accumulated under the carapace, on the external body surface, and connected to the appendages. All the silver species in this study caused abnormal swimming by the D. magna.

Conclusion: According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered.

Show MeSH
Related in: MedlinePlus