RESUMO
One of the metal detoxifying mechanisms that occurs in fish is metallothionein (MT) induction and metal binding. Hepatic MT induction has been well described, but biliary MT metal detoxification has only recently been described in fish. In this scenario, metal-metal interactions have been increasingly evaluated to further understand the behavior of these contaminants regarding homeostasis and biological functions, as well as their toxic effects. Studies, however, have been mainly conducted concerning the elemental pair Se-Hg, and scarce reports are available concerning other metal pairs. Therefore, this study aimed to evaluate biliary and hepatic MT metal detoxification mechanisms in a territorial neotropical cichlid, Geophagus brasiliensis. Fish were sampled from the anthropogenically impacted estuarine Rodrigo de Freitas Lagoon, located in Southern Rio de Janeiro, and trace elements and MT were determined by inductively coupled plasma mass spectrometry (ICP-MS) and UV-Vis spectrophotometry, respectively, in fish liver and bile. MT in bile were significantly lower than in liver. Significant differences between bile and liver were observed for many trace elements, and, although most were higher in liver, Cd and Ni were significantly higher in bile, indicating efficient excretion from the body via the biliary route. A significant correlation was observed between MT and Fe in bile, and between MT in liver and Cu and Zn in bile. Molar ratio calculations demonstrated protective elements effects against Al, As, Cd, Hg, Pb and V in both bile and liver, as well as some novel interrelationships, indicating the importance of these investigations regarding the elucidation of element detoxifying mechanisms. Furthermore, investigation of other elemental associations may aid in decision-making processes regarding environmental contamination scenarios linked to public health.
Assuntos
Bile/metabolismo , Ciclídeos/metabolismo , Fígado/metabolismo , Metalotioneína/metabolismo , Oligoelementos/metabolismo , Animais , Cádmio/metabolismo , Níquel/metabolismoRESUMO
On April 26th, 2005, an accident caused a leak of 60,000L of Diesel Oil Type "B", freighted by train wagons upstream on a mangrove area within Guanabara Bay, Southeast Brazil. After the accident, samples from animals with different biological requirements were collected in order to monitor polycyclic aromatic hydrocarbons concentrations for the following 12months. Sessile, mobile, carnivorous, omnivorous, organic detritus feeders, planktivorous and suspension feeders were some of the attributes compared. Concentrations of PAHs did not vary in relation to different dietary habits and the best response was from the sessile suspensivorous barnacles. A background level of <50microgkg(-1) was suggested based on the reference site and on values observed in the following months after the accident. The highest values of PAH concentrations were observed in barnacles in the first month immediately after the spill, decreasing to background levels after few months. Barnacles are suggested as a sentinel species.
Assuntos
Braquiúros/metabolismo , Peixes/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Thoracica/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Brasil , Vazamento de Resíduos Químicos , Ecossistema , Exposição Ambiental/análise , Monitoramento Ambiental , Petróleo/metabolismo , RhizophoraceaeAssuntos
Bile/efeitos dos fármacos , Monitoramento Ambiental/métodos , Hidrocarbonetos Policíclicos Aromáticos , Smegmamorpha/metabolismo , Poluentes Químicos da Água , Animais , Bile/química , Bile/metabolismo , Biomarcadores/análise , Peixes , Geografia , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Medição de Risco , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/farmacocinéticaRESUMO
Owing to the importance of dissolution and weathering processes following oil spills, this work focused on the operational (quantitative) aspects related to the dissolution of petroleum-derived products, as well as the influence of solar light on both dissolution and the photoproduction of hydrogen peroxide. Four Brazilian crude oil samples were used to study the transfer process of organic compounds from the crude oil film to the aqueous phase (natural seawater) over a period of up to 45 days. Dissolved organic carbon (DOC), measured by non-dispersive infrared spectroscopy followed by high temperature catalytic combustion, was used to follow the partitioning between the two phases. Aqueous DOC values increased as a function of time (up to 15 days) until equilibrium was reached at concentrations ranging from 5 to 45 mg C L(-1). The final DOC concentration as well as the rate of dissolution depends on the nature of the crude oil. When exposed to sunlight, the dissolution was enhanced by up to 67.3%, and inorganic peroxides were generated in the concentration range from 4.5 up to 8.0 micromol L(-1) after 7.3 h irradiation. These results indicate that there is a need for a standard procedure for the production of the WSF in order to generate a more reliable tool to assess the impact of oil spills on the marine environment.