Toxicity of α-Fe_2O_3 nanoparticles to Artemia salina cysts and three stages of larvae

摘要

Artemia salina cysts (capsulated and decapsulated) and larvae (instar I, II and III) were exposed to α-Fe_2O_3 nanoparticles (α-Fe_2O_3-NPs) to evaluate the effects on marine ecosystems. Hatchability, mortality and a number of ethological, morphological and biochemical parameters were selected as end-points to define the toxic responses. Results indicate that the hatchability of capsulated and decapsulated cysts was significantly decreased (p < 0.01) following exposure to 600 mg/L at 12,18,24 and 36 h. Both increases of mortality and decreases of swimming speed were shown concentration-dependent manners. The LC_(50) values for instar II and III were 177.424 and 235.495 mg/L, respectively (not calculable for instar I), the EC_(50) values for instar I, II and III were 259.956,99.064 and 129.088 mg/L, respectively. Instar II larvae show the greatest sensitive to α-Fe_2O_3-NPs, and followed by instar III, instar I, decapsulated cysts and capsulated cysts. Body lengths and individual dry weight of instar I, II and III larvae were decreased following exposure. α-Fe_2O_3-NPs attached onto the gills and body surface of larvae, resulting in irreversible damages. All of malondialdehyde content, total antioxidant capacity, reactive oxygen species and antioxidant enzymes activities were substantially increased in dose-dependent manners after exposure to α-Fe_2O_3-NPs suspensions, indicating that toxic effects were mediated by oxidative stress. Finally, the uptake result indicated that α-Fe_2O_3-NPs were ingested and distributed in the nephridial duct, primary body cavity and intestine of A. salina. Moreover, the uptake kinetics data show that the maximum α-Fe_2O_3-NPs content (8.818 mg/g) was reached at 36 h, and a steady state was reached after 60 h. The combined results indicate that α-Fe_2O_3-NPs have the potential to affect aquatic life when released into the marine ecosystems.