title: Bioavailability of cadmium and biochemical responses on the freshwater bivalve Corbicula fluminea--the role of TiO₂ nanoparticles.
abstract: The increasing and widespread applications of TiO2 engineered nanoparticles (nTiO2) led to the release of these materials into aquatic environments and consequently a change on the assessment of the environmental risk of trace metals. In this work, the role of two commercial nTiO2 with distinct crystalline phases and sizes (nTiO2-P25: 80% anatase+20% rutile, d=20nm; nTiO2-NA: 100% anatase, d=5 nm; 0.1 and 1.0 mg L(-1)) on Cd (112 μg L(-1)) speciation, biouptake and toxicity for the freshwater bivalve Corbicula fluminea was evaluated. The electroanalytical technique 'absence of gradients and Nernstian equilibrium stripping (AGNES)' was used to quantify the free Cd concentrations in the exposure medium in presence of both particles. Despite ca. 30-40% decrease of free Cd in the medium in presence of nTiO2, Cd uptake by C. fluminea was similar in the absence and presence of either of the particles. Superoxide dismutase and glutathione-S-transferase activities remained unchanged for Cd in absence and presence of nTiO2, whereas a significant increase of the catalase activity was obtained at the third day for Cd in presence of both nTiO2. Despite lipid peroxidation data shows that the presence of both nTiO2 seems to exert cells damage, a more quantitative description is not possible with the obtained data. The lack of clear-cut responses by the studied biomarkers, even when only in presence of Cd, do not allow insights into the effect of the presence of nTiO2 on the Cd toxicity to the bivalves. Notwithstanding, morphological changes in the digestive gland were clearly obtained in the presence of Cd, nTiO2 and Cd+nTiO2 indicating an inflammatory response.
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal. Electronic address: goncalo.vale@tecnico.ulisboa.pt.
authors.forename: Gonçalo
authors.initials: G
authors.lastname: Vale
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal. Electronic address: cristiana.franco@gmail.com.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Franco
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologias da Universidade Nova de Lisboa, 2829-516 Monte da Caparica, Portugal. Electronic address: mesd@fct.unl.pt.
authors.forename: Mário S
authors.initials: MS
authors.lastname: Diniz
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal. Electronic address: mcsantos@tecnico.ulisboa.pt.
authors.forename: Margarida M C
authors.initials: MM
authors.lastname: dos Santos
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal. Electronic address: rute.domingos@tecnico.ulisboa.pt.
authors.forename: Rute F
authors.initials: RF
authors.lastname: Domingos
mesh_terms: D000818:Animals; D001682:Biological Availability; D002104:Cadmium / Q000032:analysis* / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D049874:Corbicula / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004064:Digestive System / Q000187:drug effects / Q000473:pathology; D005982:Glutathione Transferase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D015227:Lipid Peroxidation / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D013054:Spectrophotometry, Atomic; D013482:Superoxide Dismutase / Q000378:metabolism; D014025:Titanium / Q000737:chemistry* / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; C009495:titanium dioxide; D014025:Titanium; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase
keywords: Bioavailability; Biomarkers; Cadmium; Corbicula fluminea; Speciation; TiO(2) nanoparticles