title: Full life-cycle toxicity assessment on triclosan using rotifer Brachionus calyciflorus.
abstract: Triclosan (TCS) is an antimicrobial and is an aquatic contaminant. Little is known on aquatic toxicity of TCS. Rotifers are common members of freshwater zooplankton. In this study, Brachionus calyciflorus was chosen as a test organism to assess the acute and complete life cycle toxicity of TCS in this study. The acute toxicity results showed that the 24-h median lethal concentration (LC50) of TCS was 345±0.11μg/L (95% confidence limits of 212-564µg/L). Reproductive bioassays demonstrated that TCS could inhibit the population growth rate at the concentration higher than 1.0μg/L. Resting egg production encompasses the full life-cycle of rotifer, and thus its hatching rate were explored to assess the toxicity of TCS towards rotifer population at TCS concentrations ranging from 0.1 to 200µg/L at two different growth periods. When resting eggs were exposed to TCS during the formation period, 0.1 and 1.0µg/L of TCS increased the hatching rate from 0.402 to 0.502, and 0.475, respectively. Exposure to 100 and 200µg/L of TCS reduced the hatching rate to 0.309 and 0.275, respectively. When the resting eggs were formed in the control medium and hatched in medium with TCS, their hatching rates were not significantly influenced by TCS, except that 200µg/L of TCS decreased the hatching rate from 0.402 to 0.34 significantly. The effects of TCS exposure on the hatching rate during the formation period were greater than those during the resting egg hatching period.
authors.affiliation: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address: lilanzhang@cqu.edu.cn.
authors.forename: Lilan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address: junfengn@bnu.edu.cn.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address: wangyu198732@gmail.com.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D000891:Anti-Infective Agents, Local / Q000633:toxicity*; D001681:Biological Assay; D004781:Environmental Exposure / Q000009:adverse effects; D005618:Fresh Water; D008018:Life Cycle Stages / Q000187:drug effects*; D012098:Reproduction / Q000187:drug effects; D012403:Rotifera / Q000187:drug effects* / Q000254:growth & development; D014260:Triclosan / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000891:Anti-Infective Agents, Local; D014874:Water Pollutants, Chemical; D014260:Triclosan
keywords: Chronic effects; Resting egg; Rotifer; Toxicity; Triclosan