title: Ecotoxicological effects of carbofuran and oxidised multiwalled carbon nanotubes on the freshwater fish Nile tilapia: nanotubes enhance pesticide ecotoxicity.
abstract: The interactions of carbon nanotubes with pesticides, such as carbofuran, classical contaminants (e.g., pesticides, polyaromatic hydrocarbons, heavy metals, and dyes) and emerging contaminants, including endocrine disruptors, are critical components of the environmental risks of this important class of carbon-based nanomaterials. In this work, we studied the modulation of acute carbofuran toxicity to the freshwater fish Nile tilapia (Oreochromis niloticus) by nitric acid treated multiwalled carbon nanotubes, termed HNO3-MWCNT. Nitric acid oxidation is a common chemical method employed for the purification, functionalisation and aqueous dispersion of carbon nanotubes. HNO3-MWCNT were not toxic to Nile tilapia at concentrations ranging from 0.1 to 3.0 mg/L for exposure times of up to 96 h. After 24, 48, 72 and 96 h, the LC50 values of carbofuran were 4.0, 3.2, 3.0 and 2.4 mg/mL, respectively. To evaluate the influence of carbofuran-nanotube interactions on ecotoxicity, we exposed the Nile tilapia to different concentrations of carbofuran mixed together with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, and 96 h of exposure, the LC50 values of carbofuran plus nanotubes were 3.7, 1.6, 0.7 and 0.5 mg/L, respectively. These results demonstrate that HNO3-MWCNT potentiate the acute toxicity of carbofuran, leading to a more than five-fold increase in the LC50 values. Furthermore, the exposure of Nile tilapia to carbofuran plus nanotubes led to decreases in both oxygen consumption and swimming capacity compared to the control. These findings indicate that carbon nanotubes could act as pesticide carriers affecting fish survival, metabolism and behaviour.
authors.affiliation: Programa de Pós Graduação do Instituto de Pesca-SP- APTA-SAA/SP, Caixa Postal 157, Cananéia, SP 11990-000, Brazil.
authors.forename: Janaína
authors.initials: J
authors.lastname: Campos-Garcia
authors.affiliation: Laboratório de Química do Sólido (LQES), Instituto de Química, Universidade Estadual de Campinas-UNICAMP, Caixa Postal 6154, Campinas, SP 13081-970, Brazil; Laboratório Nacional de Nanotecnologia (LNNano), Centro Nacional de Pesquisa em Energia e Materiais - CNPEM, Caixa Postal 6192, 13083-970 Campinas, SP, Brazil.
authors.forename: Diego Stéfani T
authors.initials: DS
authors.lastname: Martinez
authors.affiliation: Laboratório de Química do Sólido (LQES), Instituto de Química, Universidade Estadual de Campinas-UNICAMP, Caixa Postal 6154, Campinas, SP 13081-970, Brazil.
authors.forename: Oswaldo L
authors.initials: OL
authors.lastname: Alves
authors.affiliation: Polo Regional Vale do Ribeira. Rodovia BR 116, km 460 Caixa Postal 122-CEP 11900-000 Registro, SP, Brazil.
authors.forename: Antônio Fernando Gervásio
authors.initials: AF
authors.lastname: Leonardo
authors.affiliation: Programa de Pós Graduação do Instituto de Pesca-SP- APTA-SAA/SP, Caixa Postal 157, Cananéia, SP 11990-000, Brazil; Instituto de Pesca - APTA-SAA/SP, Caixa Postal 157, Cananéia, SP 11990-000, Brazil. Electronic address: edisonbarbieri@yahoo.com.br.
authors.forename: Edison
authors.initials: E
authors.lastname: Barbieri
mesh_terms: D000818:Animals; D002235:Carbofuran / Q000633:toxicity*; D023681:Cichlids / Q000502:physiology; D004357:Drug Synergism; D007306:Insecticides / Q000633:toxicity*; D037742:Nanotubes, Carbon / Q000633:toxicity*; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D007306:Insecticides; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D002235:Carbofuran
keywords: Aquatic ecotoxicology; Carbon nanotubes; Interaction; Nanotoxicity