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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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Light microscope images of daphnia exposed to nAg1 and nAg2 colloids for 24 hours. A: control; B: live daphnia exposed to 0.002 mg/L nAg1, pigmentation can been seen under the brood chamber (circles); C: dead daphnia exposed to 0.01 mg/L nAg2; D: live daphnia exposed to 0.004 mg/L nAg1; E: live daphnia exposed to 0.002 mg/L nAg2. In images C, D, and E, small bubbles can be seen under the carapace; plus, nanoparticle aggregates can be seen on the antennae, body surface, and also in the brood chamber.
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Figure 7: Light microscope images of daphnia exposed to nAg1 and nAg2 colloids for 24 hours. A: control; B: live daphnia exposed to 0.002 mg/L nAg1, pigmentation can been seen under the brood chamber (circles); C: dead daphnia exposed to 0.01 mg/L nAg2; D: live daphnia exposed to 0.004 mg/L nAg1; E: live daphnia exposed to 0.002 mg/L nAg2. In images C, D, and E, small bubbles can be seen under the carapace; plus, nanoparticle aggregates can be seen on the antennae, body surface, and also in the brood chamber.

Mentions: After exposing the Daphnia to the nAg1 and nAg2 colloids and the nAg3 suspension, some pigmentation became visible in parts of the brood chamber that was not observed with the AgNO3 treatments and in the controls (Figures 7, 8); this pigmentation may have been a sign of nanoparticle accumulation under the carapace. In addition, at higher concentrations, nanoparticle aggregates were seen to be attached to the external body surface and appendages of the D. magna (Figures 7, 8), which in some cases affected the swimming ability. Also, a notable phenomenon with the colloidal treatments (nAg1 and nAg2) was the appearance of small bubbles under the carapace of the Daphnia (Figure 7).


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)

Light microscope images of daphnia exposed to nAg1 and nAg2 colloids for 24 hours. A: control; B: live daphnia exposed to 0.002 mg/L nAg1, pigmentation can been seen under the brood chamber (circles); C: dead daphnia exposed to 0.01 mg/L nAg2; D: live daphnia exposed to 0.004 mg/L nAg1; E: live daphnia exposed to 0.002 mg/L nAg2. In images C, D, and E, small bubbles can be seen under the carapace; plus, nanoparticle aggregates can be seen on the antennae, body surface, and also in the brood chamber.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 7: Light microscope images of daphnia exposed to nAg1 and nAg2 colloids for 24 hours. A: control; B: live daphnia exposed to 0.002 mg/L nAg1, pigmentation can been seen under the brood chamber (circles); C: dead daphnia exposed to 0.01 mg/L nAg2; D: live daphnia exposed to 0.004 mg/L nAg1; E: live daphnia exposed to 0.002 mg/L nAg2. In images C, D, and E, small bubbles can be seen under the carapace; plus, nanoparticle aggregates can be seen on the antennae, body surface, and also in the brood chamber.
Mentions: After exposing the Daphnia to the nAg1 and nAg2 colloids and the nAg3 suspension, some pigmentation became visible in parts of the brood chamber that was not observed with the AgNO3 treatments and in the controls (Figures 7, 8); this pigmentation may have been a sign of nanoparticle accumulation under the carapace. In addition, at higher concentrations, nanoparticle aggregates were seen to be attached to the external body surface and appendages of the D. magna (Figures 7, 8), which in some cases affected the swimming ability. Also, a notable phenomenon with the colloidal treatments (nAg1 and nAg2) was the appearance of small bubbles under the carapace of the Daphnia (Figure 7).

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