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Planaltina, Brazil

Oliveira-Filho E.C.,Laboratorio Of Ecotoxicologia | Oliveira-Filho E.C.,Centro Universitario Of Brasilia | Filho J.S.,University of Brasilia | Novais L.A.,Centro Universitario Of Brasilia | And 3 more authors.
Environmental Science and Pollution Research | Year: 2016

This study aims to evaluate the effects of maghemite nanoparticles (γ-Fe2O3) coated with meso-2, 3-dimercaptosuccinic acid (DMSA) stabilizer on the survival and reproduction of the aquatic snail Biomphalaria glabrata. The cumulative means of egg masses and eggs per individual in the control group at the end of 4 weeks were 18.8 and 326.7, respectively. These values at the concentration of 1 mg/L were 17.2 and 291.6; at 10 mg/L, they were 19.6 and 334.4 ,and at 100 mg/L, they were 14.3 and 311.1. Results showed no significant differences between the tested and the control groups at the level of p < 0.05. Exposure of embryos for 10 days showed absence of mortality, malformation, or hatching delay. X-ray microtomography confirmed the presence of nanoparticles in exposed individuals and showed the complete elimination of the nanoparticles after 30 days in clean water. In the studied conditions, it is clear that γ-Fe2O3 coated with stabilizing DMSA did not alter the fecundity or the fertility of the snail B. glabrata after 4 weeks of exposure, and accumulation was not present after 30 days in clean water. © 2016 Springer-Verlag Berlin Heidelberg

Rivero-Wendt C.L.G.,University of Brasilia | Borges A.C.,University of Brasilia | Oliveira-Filho E.C.,Laboratorio Of Ecotoxicologia | Miranda-Vilela A.L.,University of Brasilia | And 2 more authors.
Genetics and Molecular Research | Year: 2014

17-α-methyltestosterone (MT) is a synthetic hormone used in fish hatcheries to induce male monosex. Snails hold promise as possible test models to assess chemicals acting on the endocrine system. Biomphalaria glabrata is an aquatic gastropod mollusk (Pulmonata, Planorbidae) that can be easily maintained in aquaria, predisposing the species for use in ecotoxicological testing. This study evaluated the reproductive effects of MT on B. glabrata by examining histological changes and its reproductive performance. Ten snails per group were exposed for 4 weeks to different concentrations of MT (0.01, 0.1, and 1.0 mg/L). The total number of laid eggs, egg mass per group, size of type V oocytes, and production of spermatozoids were determined. Reproduction of B. glabrata was affected by MT. At the lowest concentration (0.01 mg/L), MT caused a statistically significant increase in the number of egg mass per snail compared with controls unexposed to MT. Histopathology analyses showed an increase in the sperm production at the higher MT concentrations of 0.1 and 1.0 mg/L. Chromatographic analyses of water samples showed that MT concentrations rapidly declined within a 96-h period. These results highlight the importance of giving more support to regulatory authorities, since MT is not registered for use on fish hatcheries in many countries around the world. Wastewater from fish farms discharged into aquatic ecosystems should be monitored for MT residues, since its presence could compromise the reproduction of other native snail species. © FUNPEC-RP.

Gutierrez M.F.,CONICET | Paggi J.C.,CONICET | Gagneten A.M.,Laboratorio Of Ecotoxicologia
Ecotoxicology | Year: 2012

The purpose of this work was to experimentally analyze the impact of copper, chromium and a commercial pesticide with endosulfan on the escape behavior of two copepods (Notodiaptomus conifer, Argyrodiaptomus falcifer) and three cladocerans (Daphnia magna, Pseudosida variabilis and Ceriodaphnia dubia). The experimental assays were carried out using a novel hydraulic devise designed to mimic three-speed predator capture behavior. Two concentrations, one ''high'' and one ''low'', were employed and the exposure time was 15 (±5) minutes. With two exceptions, the species exposed to heavy metals manifested higher ability to escape than controls. Both concentrations of the pesticide reduced the escape ability of cladocerans but copepods responded, in general, in a similar manner as for heavy metals. The immediate apparent advantage of low and early toxic effects is discussed and the high sensitivity of the escape behavior suggests that it could be a complementary endpoint to be used in future ecotoxicological tests. © 2011 Springer Science+Business Media, LLC.

Faria M.,University of Aveiro | Navas J.M.,Laboratorio Of Ecotoxicologia | Soares A.M.V.M.,University of Aveiro | Barata C.,CSIC - Institute of Environmental Assessment And Water Research
Science of the Total Environment | Year: 2014

There is limited data on the sub-lethal oxidative stress effects of titanium dioxide nanoparticle aggregates (NM-TiO2) and its modulation by simulated solar radiation (SSR) to aquatic organisms. This study aimed to examine sublethal oxidative stress effects of aqueous exposure to three different types of NM-TiO2 differing in their coating or crystal structure but of similar primary size (20nm) plus a micron-sized bulk material to zebrafish embryos without and with SSR. Oxidative stress responses of known model prooxidant (tert-Butyl hydroperoxide) and photoprooxidant (fluoranthene) compounds were also studied. Results evidenced a low bio-availability of NM-TiO2 to embryos with detrimental effects on growth at 1mgml-1. Phototoxicity increased moderately, by 3 and 1.5 fold, under co-exposures to fluoranthene (100μgl-1) and to the NM-TiO2 P25 (1mgml-1), respectively, being unchanged in the other TiO2 aggregates. In vitro exposures under SSR confirmed that the NM-TiO2 P25 had the highest potential to generate reactive oxygen species (ROS). Antioxidant enzyme activities of superoxide dismutase increased shortly after exposure to the studied materials, whereas the levels of glutathione tend to be altered after longer exposures. All compounds were able to produce oxidative stress enhancing the senescence-associated β galactosidase pigment (SA-β-gal). Under SSR radiation the NM-TiO2 P25 affected antioxidant and oxidative stress responses as the phototoxic compound fluoranthene. These results indicated that despite the low bio-availability of NM-TiO2 to zebrafish embryos, P25 was phototoxic due to the production of reactive oxygen species. Nevertheless, overall our results indicated that fish development may not be at high risk in the face of NM-TiO2, even when combined with prooxidant conditions. © 2013 Elsevier B.V.

Oliveira-Filho E.C.,Laboratorio Of Ecotoxicologia | Oliveira-Filho E.C.,Centro Universitario Of Brasilia | Muniz D.H.F.,Laboratorio Of Ecotoxicologia | Freire I.S.,Laboratorio Of Ecotoxicologia | And 6 more authors.
Ecotoxicology | Year: 2011

Microbial pest control agents or entomopathogens have been considered an interesting alternative to use instead of chemical insecticides. Knowledge of ecotoxicity data is very important to predict the hazard of any product released in the environment and subsidize the regulation of these products by governmental agencies. In the present study four new Brazilian strains of Bacillus and one fungus were tested to evaluate their acute toxicity to the microcrustacean Daphnia similis, the snail Biomphalaria glabrata and the dung beetle Digitonthophagus gazella. The microcrustaceans and the snails were exposed to entomopathogens in synthetic softwater and the beetles were exposed directly in cattle dung. Obtained data reveal low susceptibility of the non-target species to tested microorganisms, with lethal concentrations being observed only at much higher concentrations than that effective against target insects. These results show that the tested strains are selective in their action mode and seem to be non-hazardous to non-target species. © 2011 Springer Science+Business Media, LLC.

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