Acute and chronic response of Daphnia magna exposed to TiO2 nanoparticles in agitation system.
Aquatic toxicity of titanium dioxide nanoparticles (TiO2 NPs) to Daphnia magna was characterized using a completely stirred bioassay system intended to keep particles in suspension thereby maintaining a consistent exposure. The 48-h LC50 was 4.5 mg/L TiO2 NPs, whereas LC50 values for 7 and 14-days exposures were 2.7 and 1.9 mg/L, respectively. An exposure of 1.5 mg/L over a 21-days exposure resulted in significant reductions in fecundity. While reproduction was initially reduced in the 0.5 and 1.0 mg/L exposures, it recovered and was similar to the control by 21 days. For reproduction inhibition, NOEC was 1.0 mg/L. Exposure to 2.5 mg/L TiO2 NPs resulted in 40 % of the organisms failing to become gravid; all surviving organisms exposed to 5.0 mg/L failed to become gravid. The increased sensitivity was due to the refinement in the bioassay system that kept NP in suspension resulting in consistent exposure concentrations.
Department of Environmental Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul, 139-743, South Korea, ktkim@seoultech.ac.kr.
Ki-Tae
KT
Kim
Stephen J
SJ
Klaine
Sang D
SD
Kim
D000704:Analysis of Variance; D000818:Animals; D003621:Daphnia / Q000187:drug effects*; D007928:Lethal Dose 50; D053758:Nanoparticles / Q000633:toxicity*; D019055:No-Observed-Adverse-Effect Level; D012098:Reproduction / Q000187:drug effects; D013997:Time Factors; D014025:Titanium / Q000633:toxicity*; D023382:Toxicity Tests, Acute; D036401:Toxicity Tests, Chronic; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium