Genotoxicity, potential cytotoxicity and cell uptake of titanium dioxide nanoparticles in the marine fish Trachinotus carolinus (Linnaeus, 1766).

Nanoparticles have physicochemical characteristics that make them useful in areas such as science, technology, medicine and in products of everyday use. Recently the manufacture and variety of these products has grown rapidly, raising concerns about their impact on human health and the environment. Adverse effects of exposure to nanoparticles have been reported for both terrestrial and aquatic organisms, but the toxic effects of the substances on marine organisms remain poorly understood. The main aim of this study was to evaluate the genotoxicity of TiO2-NP in the marine fish Trachinotus carolinus, through cytogenotoxic methods. The fish received two different doses of 1.5 µg and 3.0 µg-TiO2-NP g(-1) by intraperitoneal injection. Blood samples were collected to analyze erythrocyte viability using the Trypan Blue exclusion test, comet assay (pH>13), micronucleus (MN) and other erythrocyte nuclear abnormalities (ENA) 24, 48 and 72 h after injection. The possible cell uptake of TiO2-NP in fish injected with the higher dose was investigated after 72 h using transmission electron microscopy (TEM). The results showed that TiO2-NP is genotoxic and potentially cytotoxic for this species, causing DNA damage, inducing the formation of MN and other ENA, and decreasing erythrocyte viability. TEM examination revealed that cell uptake of TiO2-NP was mainly in the kidney, liver, gills and to a lesser degree in muscle. To the extent of the authors' knowledge, this is the first in vivo study of genotoxicity and other effects of TiO2-NP in a marine fish.

Effects of anionic surfactant and salinity on the bioenergetics of juveniles of Centropomus parallelus (Poey).

The acute and sublethal chronic effects of sodium dodecyl sulphate (SDS) on the survival, metabolism, and growth of juveniles of Centropomus parallelus were investigated at three different salinities. Results of 96 h LC50 test showed that juveniles of C. parallelus were very sensitive to SDS in comparison to other species investigated. For each group of exposure to nominal concentrations of SDS (0.10 and 0.25 mg/L) and the control group (0.0 mg/L), at the different salinities (5, 20, and 30) there were significant differences in the specific growth rate, oxygen consumption, and ammonia excretion rates, O:N atomic ratio at the different exposure periods (15 and 30 days). There were also interactions between factors for the parameters investigated. The present results show a pronounced effect of SDS, mainly at the highest concentration and salinity, as well as after a long time of exposure.