salinity-dependent-toxicity-assay-silver-nanocolloids-using-medaka

Salinity-dependent Toxicity Assay of Silver Nanocolloids Using Medaka Eggs

Salinity is an important characteristic of the aquatic environment. For aquatic organisms it defines the habitats of freshwater, brackish water, and ...

In this study, the effects of silver nanocolloids (SNCs) on the early life stages of the reef-building coral Acropora japonica were investigated. The tolerance of this species to SNC contamination was estimated by exposing gametes, larvae, and primary polyps to a range of SNC concentrations (0, 0.5, 5, 50, and 500 μg l(-1)). Pure SNCs were immediately ionized to Ag(+) in seawater and concentrations of ≥50 μg l(-1) SNC had a significant detrimental effect on fertilization, larval metamorphosis, and primary polyp growth. Exposure to 50 μg l(-1) SNC did not significantly affect larval survival; however, the larvae were deformed and lost their ability to metamorphose. At the highest concentration (500 μg l(-1) SNC), all gametes, larvae, and primary polyps died. These experiments provide the first data on the effects of silver-nanomaterial-contaminated seawater on cnidarians, and suggest that silver nanomaterials can influence the early development of corals through anthropogenic wastewater inputs.

Effects of silver nanocolloids on early life stages of the scleractinian coral Acropora japonica.

We investigated the interspecific variation of silver nanoparticle (SNP) sensitivity in common cladocerans (Daphnia magna, D. galeata, and Bosmina longirostris) and the exact cause of both acute and chronic toxicity focusing on the form of silver (NPs and ions). Materials tested were non-surface-coated silver nanocolloids (SNCs) and AgNO3. The results of the acute toxicity tests support the theory that the effects of SNPs on aquatic organisms is mainly due to Ag(+) released from SNPs. Among the three cladocerans, D. galeata was more sensitive to silver (as Ag(+)) than both D. magna and B. longirostris. Moreover, the chronic toxicity of SNCs was also derived from dissolved silver (especially Ag(+)). SNCs (as total silver concentration) showed far lower chronic compared with acute toxicity to daphnids because the amount of dissolved silver decreased in the presence of prey algae. The chronic end-point values (EC10 values for net reproductive rate and the probability of survival to maturation) did not differ largely from acute ones (48-h EC50 obtained from acute toxicity tests and 48-h LC50 estimated by the biotic ligand model) when the values were calculated based on Ag(+) concentration. The α value (concentration at which intrinsic population growth rate is decreased to zero) estimated by a power function model was a reliable parameter for assessing the chronic toxicity of silver.

Article	Year
Effects of silver nanocolloids on early life stages of the scleractinian coral Acropora japonica. Marine environmental research\| PubMed ID: 25047545	2014
Free silver ion as the main cause of acute and chronic toxicity of silver nanoparticles to cladocerans. Archives of environmental contamination and toxicology\| PubMed ID: 25352442	2015

Chisato Kataoka

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