Avaliação dos níveis de metais pesados no pantanal dos Marimbus, Bahia, Brasil / Evaluation of heavy metals in levels of wetland Marimbus, Bahia, Brazil

RESUMO A concentração de metais pesados zinco (Zn), chumbo (Pb), cromo (Cr), níquel (Ni), cobre (Cu) e cádmio (Cd) tem aumentado nos últimos anos nos compartimentos aquáticos em função do uso indiscriminado de fertilizantes na agricultura, da falta de saneamento e do descarte de resíduos industriais não tratados. O objetivo deste trabalho foi investigar a disponibilidade dos metais pesados nas águas e em Salvinia auriculata Aubl. das áreas alagadas dos Marimbus, Bahia. As amostras foram submetidas à digestão ácida (HNO3; HClO4) e as análises dos metais pesados utilizaram um aparelho de absorção atômica de chama ar-acetileno. Nas águas, foram detectados teores de chumbo e zinco com valores dentro dos limites permissíveis para águas de classe 1, conforme Resolução CONAMA nº 357/2005 (BRASIL, 2005). Em S. auriculata, observou-se acumulação de concentração de metais na seguinte ordem Zn>Cr>Pb>Ni>Cu. Conclui-se que a presença da S. auriculata nos corpos hídricos funciona como importante removedor de metais pesados e sua presença nos ambientes aquáticos é extremamente relevante para permitir os diversos usos que esse espaço proporciona.

ABSTRACT In recent years, concentration of heavy metals like zinc (Zn), lead (Pb), chromium (Cr), nickel (Ni), copper (Cu) and cadmium (Cd) has increased over the past years in water bodies due to indiscriminate use of fertilizers in agriculture, lack of sanitation and irregular disposal of untreated industrial waste. The main goal of this study was to investigate the presence of heavy metals in the water and in the Salvinia auriculata Aubl. found in flooded areas of Marimbus, Bahia. The samples were subjected to acid digestion (HNO3, HClO4) and the analyses of heavy metals used an air-acetylene flame atomic absorption spectrometer. The detected levels of lead and zinc found in the water samples were within the limits set for water class 01 by CONAMA no. 357/2005 (BRASIL, 2005). An accumulation of metal concentration in the order of Zn>Cr>Pb>Ni>Cu was observed in S. auriculata. Thus, the presence of S. auriculata in water bodies serves as an important remover of heavy metals and their presence in aquatic environments is extremely important to allow the various uses such environments may provide.

Acute intraperitoneal mercury chloride contamination and distribution in liver, muscle and gill of a neotropical fish Hoplias malabaricus (BLOCK, 1794)

The present study investigated with the distribution of mercury chloride in muscle, liver and gills of Hoplias malabaricus contaminated through intraperitoneal injection (6 µg in 0.1mL of PBS) for a period of 24, 48, 72 and 96h. The liver, gill and muscle were analyzed for mercury content in an ICP/AES (Varian Liberty II) with vapor generating accessory (VGA 77). The muscle and liver tissues presented the same contamination pattern increasing concentrations in 24 h of exposure with a decrease in Hg concentration with 72 h and a new increase in Hg concentrations with 96 h of exposure. The Hg concentrations in contaminated organisms were always higher than the control although only for liver samples the difference was statistically significant. Liver samples always presented higher Hg contents when compared with gill and muscle samples.