Ag Nanoparticles (Ag NM300K) in the Terrestrial Environment: Effects at Population and Cellular Level in Folsomia candida (Collembola)

Abstract

The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K) in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days) and oxidative stress markers (0, 2, 4, 6, 10 days). The standard species Folsomia candida was used. Measured markers included catalase (CAT), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (TG), metallothionein (MT) and lipid peroxidation (LPO). Results showed that AgNO3 was more toxic than AgNPs at the population level: reproduction EC20 and EC50 was ca. 2 and 4 times lower, respectively. At the cellular level Correspondence Analysis showed a clear separation between AgNO3 and AgNP throughout time. Results showed differences in the mechanisms, indicating a combined effect of released Ag+ (MT and GST) and of AgNPs (CAT, GR, TG, LPO). Hence, clear advantages from mechanistic approaches are shown, but also that time is of importance when measuring such responses.

Effect of silver nanoparticles on the standard soil arthropod Folsomia candida (Collembola) and the eukaryote model organism Saccharomyces cerevisiae

“…According to Mendes and co-worker, the amount of MT in F. candida treated with AgNPs and AgNO 3 was increased at 48-h exposure and the amount of MT treated with the latter was higher than with the former one [38]. Furthermore, at population level, a dose–response effect of AgNPs is lower than that of AgNO 3 [38].…”

“…Furthermore, at population level, a dose–response effect of AgNPs is lower than that of AgNO 3 [38]. The increased amount of MT at cellular level is directly correlated to an up-regulated MTC mRNA and might confirm the toxic effect to F. candida via silver ions released from AgNPs.…”

Antioxidant Enzyme Activity and Lipid Peroxidation in Aporrectodea caliginosa Earthworms Exposed to Silver Nanoparticles and Silver Nitrate in Spiked Soil

“…Such high concentrations can lead to marked irreversible enzymatic and metabolic changes. Mendes et al (2015), in a similar study but with Folsomia candida (a member of the order Collembola, a common and widespread arthropod that occurs in soils throughout the world), found that the increases in metallothionein and GST > CAT, GR, GSH, and LPO were more marked in those exposed to Ag + than in those exposed to AgNPs.…”

Collembola Reproduction Decreases with Aging of Silver Nanoparticles in a Sewage Sludge-Treated Soil

“…In an agricultural silt loam soil the EC 50 was estimated >1,855 mg Ag kg −1 for PVP-coated AgNP (Velicogna et al, 2016). With AgNP and LUFA 2.2 soil a dose-response pattern was detected at the concentration range of 64-640 mg Ag kg −1 for F. candida reproduction and the EC 50 was at 540 mg kg −1 (Mendes et al, 2015).…”