title: Effects of artificial sweeteners on metal bioconcentration and toxicity on a green algae Scenedesmus obliquus.
abstract: The ecotoxicity of heavy metals depends much on their speciation, which is influenced by other co-existing substances having chelating capacity. In the present study, the toxic effects of Cd(2+) and Cu(2+) on a green algae Scenedesmus obliquus were examined in the presence of two artificial sweeteners (ASs), acesulfame (ACE) and sucralose (SUC) by comparing the cell specific growth rate μ and pulse-amplitude-modulated (PAM) parameters (maximal photosystem II photochemical efficiency Fv/Fm, actual photochemical efficiency Yield, and non-photochemical quenching NPQ) of the algae over a 96-h period. Simultaneously, the bioconcentration of the metals by the algal cells in the presence of the ASs was measured. The presence of ACE enhanced the growth of S. obliquus and promoted the bioconcentration of Cd(2+) in S. obliquus, while the impacts of SUC were not significant. Meanwhile, EC50 values of Cd(2+) on the growth of S. obliquus increased from 0.42 mg/L to 0.54 mg/L and 0.48 mg/L with the addition of 1.0 mg/L ACE and SUC, respectively. As for Cu(2+), EC50 values increased from 0.13 mg/L to 0.17 mg/L and 0.15 mg/L with the addition of 1.0 mg/L ACE and SUC, respectively. In summary, the two ASs reduced the toxicity of the metals on the algae, with ACE showing greater effect than SUC. Although not as sensitive as the cell specific growth rate, PAM parameters could disclose the mechanisms involved in metal toxicity at subcellular levels. This study provides the first evidence for the possible impact of ASs on the ecotoxicity of heavy metals.
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Hu
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Deng
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Fan
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. Electronic address: sunhongwen@nankai.edu.cn.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Sun
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Gan
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Hongkai
authors.initials: H
authors.lastname: Zhu
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Yao
mesh_terms: D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D044444:Scenedesmus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012995:Solubility; D013395:Sucrose / Q000031:analogs & derivatives / Q000032:analysis / Q000494:pharmacology; D013549:Sweetening Agents / Q000032:analysis / Q000494:pharmacology*; D013843:Thiazines / Q000032:analysis / Q000494:pharmacology; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D013549:Sweetening Agents; D013843:Thiazines; D014874:Water Pollutants, Chemical; D002104:Cadmium; D013395:Sucrose; D003300:Copper; C026285:trichlorosucrose; C006362:acetosulfame
keywords: Algae; Artificial sweeteners; Bioconcentration; Complex effects; Heavy metals; Toxicity