title: Effects of silica nanoparticles on growth and photosynthetic pigment contents of Scenedesmus obliquus.
abstract: To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles (BPs) suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration (EC20) values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentration (50, 100, and 200 mg/L) of SiO2 NPs after 96-hr exposure, but the carotenoids did not. SiO2 BPs were found to be nontoxic up to 200 mg/L. The toxicity of SiO2 NPs probablely due to their sorption to algal cells surface. The results imply that there is potential harm to aquatic environment by using SiO2 NPs, and it should deserve special concern.
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Huazhong Normal University, Wuhan 430079, China. weicx@mails.ccnu.edu.cn
authors.forename: Chenxi
authors.initials: C
authors.lastname: Wei
authors.forename: Yanbo
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.forename: Bing
authors.initials: B
authors.lastname: Han
authors.forename: Xu
authors.initials: X
authors.lastname: Yang
authors.forename: Junlin
authors.initials: J
authors.lastname: Yuan
mesh_terms: D002338:Carotenoids / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D008855:Microscopy, Electron, Scanning; D045663:Quantum Dots; D044444:Scenedesmus / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development; D012822:Silicon Dioxide / Q000737:chemistry / Q000633:toxicity*; D013056:Spectrophotometry, Ultraviolet; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D002338:Carotenoids; C037184:chlorophyll b; D012822:Silicon Dioxide; D000077194:Chlorophyll A