title: Influence of Speciation of Thorium on Toxic Effects to Green Algae Chlorella pyrenoidosa.
abstract: Thorium (Th) is a natural radioactive element present in the environment and has the potential to be used as a nuclear fuel. Relatively little is known about the influence and toxicity of Th in the environment. In the present study, the toxicity of Th to the green algaeChlorella pyrenoidosa(C. pyrenoidosa) was evaluated by algal growth inhibition, biochemical assays and morphologic observations. In the cultural medium (OECD TG 201), Th(NO₃)₄ was transformed to amorphous precipitation of Th(OH)₄ due to hydrolysis. Th was toxic toC. pyrenoidosa, with a 96 h half maximum effective concentration (EC50) of 10.4 μM. Scanning electron microscopy shows that Th-containing aggregates were attached onto the surface of the algal cells, and transmission electron microscopy indicates the internalization of nano-sized Th precipitates and ultrastructural alterations of the algal cells. The heteroagglomeration between Th(OH)₄ precipitation and alga cells and enhanced oxidative stress might play important roles in the toxicity of Th. To our knowledge, this is the first report of the toxicity of Th to algae with its chemical species in the exposure medium. This finding provides useful information on understanding the fate and toxicity of Th in the aquatic environment.
authors.affiliation: School of Public Health, University of South China, Hengyang 421001, China. vintagecancan@icloud.com.
authors.forename: Can
authors.initials: C
authors.lastname: Peng
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. mayh@ihep.ac.cn.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. dingyy@ihep.ac.cn.
authors.forename: Yayun
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. hx421@ihep.ac.cn.
authors.forename: Xiao
authors.initials: X
authors.lastname: He
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. pengzhang@ihep.ac.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. lantu@ihep.ac.cn.
authors.forename: Tu
authors.initials: T
authors.lastname: Lan
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. dwang@ihep.ac.cn.
authors.forename: Dongqi
authors.initials: D
authors.lastname: Wang
authors.affiliation: School of Public Health, University of South China, Hengyang 421001, China. zhaohuizzh@126.com.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. zhangzhy@ihep.ac.cn.|School of Physical Sciences, University of the Chinese Academy of Sciences, Beijing 100049, China. zhangzhy@ihep.ac.cn.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D002708:Chlorella / Q000254:growth & development / Q000528:radiation effects* / Q000648:ultrastructure; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004307:Dose-Response Relationship, Radiation; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D018384:Oxidative Stress / Q000528:radiation effects; D011834:Radiation Monitoring / Q000379:methods*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013910:Thorium / Q000737:chemistry / Q000633:toxicity*; D014875:Water Pollutants, Radioactive / Q000737:chemistry / Q000633:toxicity*
chemical_list: D017382:Reactive Oxygen Species; D014875:Water Pollutants, Radioactive; D002734:Chlorophyll; D013910:Thorium; D000077194:Chlorophyll A
keywords: Chlorella pyrenoidosa; green algae; speciation; thorium; toxicity