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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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Photograph comparing appearance of aqueous stocks of nanoparticles (400 mg/L) used for toxicity tests. A: nAg1 colloid; B: nAg2 colloid; C: suspensions of nAg3 before (left) and after (right) 24 hours.
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Figure 6: Photograph comparing appearance of aqueous stocks of nanoparticles (400 mg/L) used for toxicity tests. A: nAg1 colloid; B: nAg2 colloid; C: suspensions of nAg3 before (left) and after (right) 24 hours.

Mentions: The nAg1 and nAg2 colloids (Figure 6) remained very stable in the exposure media (confirmed by UV-vis spectrophotometry, data not shown), and there were no signs of precipitation of the nanoparticles in the test beakers. In the case of the suspension of nAg3, sediments of aggregated nanoparticles became gradually visible at the bottom of the test beakers with the elapse of time; nonetheless, after 24 hours (and before refreshing the exposure media), most of the nAg3 particles were still suspended in the water (Figure 6).


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)

Photograph comparing appearance of aqueous stocks of nanoparticles (400 mg/L) used for toxicity tests. A: nAg1 colloid; B: nAg2 colloid; C: suspensions of nAg3 before (left) and after (right) 24 hours.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Photograph comparing appearance of aqueous stocks of nanoparticles (400 mg/L) used for toxicity tests. A: nAg1 colloid; B: nAg2 colloid; C: suspensions of nAg3 before (left) and after (right) 24 hours.
Mentions: The nAg1 and nAg2 colloids (Figure 6) remained very stable in the exposure media (confirmed by UV-vis spectrophotometry, data not shown), and there were no signs of precipitation of the nanoparticles in the test beakers. In the case of the suspension of nAg3, sediments of aggregated nanoparticles became gradually visible at the bottom of the test beakers with the elapse of time; nonetheless, after 24 hours (and before refreshing the exposure media), most of the nAg3 particles were still suspended in the water (Figure 6).

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