RESUMEN
The study of the toxic effect of carbofuran and multiwalled carbon nanotubes (MWCNTs) on Astyanax ribeirae metabolism is of paramount importance due to the increasing use of this pesticide in agriculture and in the production of nanotubes within the material industry. This study aimed to evaluate the effects of carbofuran, MWCNT, and the combination of these compounds on specific oxygen consumption and excretion of ammonia in A. ribeirae. Therefore, 65 fish were divided into three groups of treatments at varying concentrations: carbofuran (0.01, 0.05, 0.1, and 0.5 mg/L), MWCNT (0.1, 0.25, 0.5, and 1.0 mg/L), and 0.5 mg/L of MWCNT added to carbofuran concentrations (0.01, 0.05, 0.1, and 0.5 mg/L). The average specific oxygen consumption in the groups exposed to carbofuran, compared to the control, increased 73.49% at the 0.01 mg/L concentration and decreased 63.86% and 91.57% with treatments of 0.1 and 0.5 mg/L, respectively. For groups exposed to the MWCNT, there was an 83.91% drop with the 1.0 mg/L treatment, and the carbofuran + MWCNT groups recorded a decrease of 71.09%, 92.77%, and 93.98% at concentrations of 0.05, 0.1, and 0.5 mg/L, respectively. In relation to specific ammonia excretion, in groups exposed to carbofuran compared to the control, there was an increase of 134.37% and 200% with the 0.1 and 0.5 mg/L treatments, respectively. The group exposed to carbofuran + MWCNT experienced a decrease of 60% and 80% with treatments of 0.1 mg/L carbofuran + 0.5 mg/L MWCNT and 0.5 mg/L carbofuran + 0.5 mg/L MWCNT, respectively. Therefore, it was concluded that carbofuran + MWCNT interact, increasing the effects in Astyanax sp.
Asunto(s)
Carbofurano/toxicidad , Characiformes/metabolismo , Nanotubos de Carbono/toxicidad , Consumo de Oxígeno/efectos de los fármacos , Plaguicidas/toxicidad , Contaminantes Químicos del Agua/toxicidad , Amoníaco/metabolismo , Animales , Femenino , MasculinoRESUMEN
O nitrogênio possui um papel-chave em sistemas aquáticos, especialmente nos ambientes de transição entre águas marinhase doces como os estuários. Assim sendo, muitos organismos, como as ostras, podem ser afetados pelo aumentoda concentração em determinadas épocas, limitando assim seu cultivo. O objetivo deste estudo foi avaliar aspectos daqualidade da água das áreas utilizadas para o cultivo da ostra do mangue Crassostrea spp. em Cananeia (SP, Brasil) e desua adequabilidade para o cultivo dos moluscos com relação às concentrações de nitrogênio amoniacal, nitrito e nitrato.O nitrogênio amoniacal variou de 0,8 a 3,2 μmol/L, o nitrito, de 0,1 a 3,2 μmol/L, e o nitrato, de 0,1 a 1,9 μmol/L. Ao analisaresses dados em todas as estações, verificou-se que o nitrogênio amoniacal, o nitrito e o nitrato foram estatisticamentediferentes entre as marés de quadratura e alta de sizígia. Como não houve diferença entre as estações que fazem a engordadas ostras e a estação Agrossolar (controle), concluiu-se que a atividade no estuário de Cananeia não causa incrementosignificativo nas concentrações de amônia, nitrito e nitrato. As concentrações registradas em Cananeia são similares àsobservadas para outras regiões tropicais e subtropicais estuarinas do mundo.
Nitrogen plays a key role in aquatic systems, especially in environments which are influenced both by marine and freshwater,such as estuaries. The aim of this study was to evaluate aspects of water quality of Crassostrea spp. aquaculture sites inCananeia (SP, Brazil) and adequacy thereof for the cultivation of mollusks in relation to concentrations of total ammoniacalnitrogen, nitrite and nitrate. Variations in concentrations of total ammoniacal nitrogen were 0.8 to 3.2 μmol/L, nitrite 0.1to 3.2 μmol/L, and nitrate from 0.1 to 1.9 μmol/L. Analyzing these data in all seasons together, we found that average totalammoniacal nitrogen and nitrite levels were significantly different for the tides and neap tide. These concentrations recordedat Cananeia are similar to those observed for other estuarine tropical and subtropical regions of the world.