title: Size-dependent ecotoxicity of barium titanate particles: the case of Chlorella vulgaris green algae.
abstract: Studies have been demonstrating that smaller particles can lead to unexpected and diverse ecotoxicological effects when compared to those caused by the bulk material. In this study, the chemical composition, size and shape, state of dispersion, and surface's charge, area and physicochemistry of micro (BT MP) and nano barium titanate (BT NP) were determined. Green algae Chlorella vulgaris grown in Bold's Basal (BB) medium or Seine River water (SRW) was used as biological indicator to assess their aquatic toxicology. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic activity were evaluated. Tetragonal BT (~170 nm, 3.24 m(2) g(-1) surface area) and cubic BT (~60 nm, 16.60 m(2) g(-1)) particles were negative, poorly dispersed, and readily aggregated. BT has a statistically significant effect on C. vulgaris growth since the lower concentration tested (1 ppm), what seems to be mediated by induced oxidative stress caused by the particles (increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content). The toxic effects were more pronounced when the algae was grown in SRW. Size does not seem to be an issue influencing the toxicity in BT particles toxicity since micro- and nano-particles produced significant effects on algae growth.
authors.affiliation: Núcleo de Pesquisa e Inovação em Ciências da Saúde (NUPICS), Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil.
authors.forename: Hudson C
authors.initials: HC
authors.lastname: Polonini
authors.forename: Humberto M
authors.initials: HM
authors.lastname: Brandão
authors.forename: Nádia R B
authors.initials: NR
authors.lastname: Raposo
authors.forename: Marcos Antônio F
authors.initials: MA
authors.lastname: Brandão
authors.forename: Ludovic
authors.initials: L
authors.lastname: Mouton
authors.forename: Alain
authors.initials: A
authors.lastname: Couté
authors.forename: Claude
authors.initials: C
authors.lastname: Yéprémian
authors.forename: Yann
authors.initials: Y
authors.lastname: Sivry
authors.forename: Roberta
authors.initials: R
authors.lastname: Brayner
mesh_terms: D017609:Barium Compounds / Q000633:toxicity*; D048408:Chlorella vulgaris / Q000187:drug effects* / Q000502:physiology*; D005602:France; D053768:Metal Nanoparticles / Q000633:toxicity*; D014025:Titanium / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D017609:Barium Compounds; D014874:Water Pollutants, Chemical; D014025:Titanium