Resumo Diante da toxicidade do mercúrio para o ser humano e para o meio ambiente, o objetivo deste trabalho foi avaliar a sua bioacumulação em 13 espécies de peixes com diferentes hábitos alimentares, capturados no reservatório de Três Marias, bacia do rio São Francisco, no período de março de 2012 a abril de 2013. Os resultados obtidos revelam que as espécies com hábito alimentar carnívoro apresentaram as maiores concentrações médias de mercúrio em músculo, com destaque para Serrasalmus brandtii (pirambeba) e Pygocentrus piraya (piranha), com concentrações de 0,4147 ± 0,2744 μg g-1 e 0,1774 ± 0,2980 μg g-1, respectivamente. Considerando as concentrações médias, todas as espécies estudadas apresentaram teores de mercúrio abaixo dos limites máximos de 0,5 μg g-1 em peixes não predadores e de 1,0 μg g-1 em peixes predadores, estabelecidos pela Agência Nacional de Vigilância Sanitária. Levando em conta cada espécie, os valores mínimos e máximos de mercúrio nos tecidos muscular e hepático demonstraram uma ampla dispersão. Em 4% dos espécimes de pirambeba e 7% de piranha, os teores de mercúrio em músculo ultrapassaram o limite estabelecido pela ANVISA para peixes predadores, e, portanto, sendo impróprios para o consumo humano. As demais espécies não apresentaram amostras de músculo com teor de Hg acima do estabelecido em lei. Devido ao seu hábito alimentar carnívoro e sua ampla distribuição na bacia do rio São Francisco, Serrasalmus brandtii pode ser considerada como biomonitor, capaz de bioacumular mercúrio, indicando, assim, o nível de contaminação desse metal no ambiente aquático em que vive.

Abstract The objective of this work was to evaluate the bioaccumulation of mercury in 13 species of fish with different eating habits, captured in the Três Marias Reservoir, São Francisco Basin, from March 2012 to April 2013. The results obtained showed that the species with carnivorous eating habit presented the highest average concentrations of mercury in muscle, especially Serrasalmus brandtii (pirambeba) and Pygocentrus piraya (piranha), with concentrations of 0.4147 ± 0.2744 μg g-1 and 0.17774 ± 0.2980 μg g-1, respectively. Considering the average concentrations, all the species studied showed levels of mercury below the maximum limit of 0.5 μg g-1 in non-predatory fish and 1.0 μg g-1 in predatory fish, established by the Agência Nacional de Vigilância Sanitária. Taking each species into account, the minimum and maximum values of mercury in the muscular and hepatic tissues showed a wide dispersion. In 4% of the specimens of pirambeba and 7% of piranha, the contents of mercury in muscle exceeded the limit established by ANVISA for predatory fish, and therefore, were unfit for human consumption. The other species did not present muscle samples with Hg content above that established by law. Due to its carnivorous eating habit and its wide distribution in the São Francisco Basin, Serrasalmus brandtii can be considered a biomonitor, capable of bioaccumulating mercury, thus indicating the level of contamination in the aquatic environment in which it lives.

The organic matter (OM) contained in a natural aquatic environment, located in a tropical region in Notheastern Brazil, was characterized using synchronous fluorescence spectroscopy and UV-Vis absorbance. The synchronous fluorescence spectra did not show qualitative differences for samples collected during dry and rainy seasons. They also revealed two peaks, one at 390 nm and other at 460 nm, associated with humic substances. The lack of peaks with significant fluorescence intensity at 270 - 300 nm and at 320 - 370 nm confirms it is an environment with natural OM. The A254/A436 ratios obtained during the dry and rainy seasons (13.55 to 14.97) indicate the presence of allochthonous OM of terrestrial origin, with high level of aromatic carbon associated with humic substances. The OM photodegradation by natural sunlight was more pronounced in the first five days, with a decrease of FImax from 23.6 to 55.4%. Also, titration with Cu(II) ions was used to determine the complexation ability of the two fluorescent sites, obtaining log K values of 4.26 and 4.27.

RESUMO A contaminação de corpos d’água por fontes difusas e pontuais em mananciais tem causado preocupações principalmente pelas restrições em sua qualidade. O problema torna-se ainda mais grave quando a contaminação afetar a água destinada ao consumo humano, como ocorre no rio São Francisco, que é a principal fonte de água para abastecimentos de várias cidades do nordeste do Brasil. Neste sentido, o objetivo deste estudo foi avaliar a qualidade da água em onze afluentes do rio São Francisco no seu baixo curso no período de 2013 a 2014, para subsidiar tomadas de decisões por parte de órgãos de gestão pública que atuam na região. Utilizou-se, para isso, o Índice de Qualidade da Água (IQA) e o Índice de Estado Trófico (IET), também foram utilizadas técnicas de agrupamento hierárquico associado as amostras para comparar as diferentes fontes de contaminação de cada manancial. Os menores valores de IQA foram determinados no rio Betume e Jacaré e estão associados a altas concentrações de coliformes provenientes do despejo de efluentes doméstico das cidades ribeirinhas. Observou-se, ainda, uma tendência a eutrofização do riacho Jacaré e dos rios Santo Antônio, dos Pilões, Papagaio e Capivara demonstrada pelo alto IET no período chuvoso. Os resultados da análise de agrupamento de amostras apresentaram proximidades com relação a sua distância euclidiana, e isso demonstra que houve relações de similaridade entre os mananciais distintos relacionados a seus parâmetros de qualidade da água. Neste trabalho também foi utilizada a Análise Fatorial que resultou na seleção de cinco fatores indicadores de qualidade da água que estão relacionados, principalmente, com o conteúdo mineral, matéria orgânica, escoamento superficial e grau de poluição. Dessa forma, conclui-se que a qualidade da água dos afluentes do rio São Francisco apresenta indícios de contaminação e que seus afluentes necessitam de um monitoramento constante para as decisões de gestão ambiental sejam as mais adequadas para sobrevivência sustentável das comunidades ribeirinhas.

ABSTRACT Contamination of water body by diffuse and point sources in springs has caused concerns mainly due to restrictions on its quality. The problem becomes more serious when contamination affects water for human consumption, as occurs in the river São Francisco, which supplies several municipalities of Sergipe. In this sense, the objective of the study was to evaluate water quality in eleven tributaries of the São Francisco river in its low course in the period from 2013 to 2014, in order to subsidize decision making by public management bodies operating in the region. For this purpose, it was used the Water Quality Index (WQI) and the Trophic State Index (TSI), as well the hierarchical grouping techniques associated to the samples to compare the different causes of contamination of each source. The lowest WQI values were observed in the rivers Betume and Jacaré and they were associated with high concentrations of coliforms related to the disposal of domestic effluents from the riverside cities. It was observed a tendency to eutrophication in the Jacaré stream, Santo Antônio, Pilões, Papagaio and Capivara rivers demonstrated by the high TSI in the rainy season. The results of the cluster analysis were close to their Euclidean distance, and showed that there were similarity relationships between the different water sources related to their parameters of water quality. In this piece of work, we also used the Factor Analysis resulted in the selection of five factors of water quality indicators which are mainly related to mineral content, organic matter, surface runoff and the level of pollution. Thus, it is concluded that the water quality of the São Francisco river tributaries is at a strong tendency towards contamination and that its tributaries need a constant monitoring for the environmental management decisions to be the most adequate for the sustainable survival of the riverside communities.

Lead is one of the heavy metals most used in industry. Poisoning due to long-term lead exposure is known as saturnism, and is an occupational illness that has been known for many years. Lead is highly toxic and can compromise the structural and functional patterns of organs and systems. The aim of this study was to examine the lungs and kidneys of fetuses from female Wistar rats exposed to lead acetate. In this study, the lungs and kidneys of 20 fetuses from female rats that had previously been treated with lead acetate were dissected, fixed, embedded in paraffin and stained with hematoxylin and eosin. Macroscopic changes to the shape, color and consistency of organs from fetuses treated with this heavy metal were observed, in comparison with organs from control fetuses. Microscopic lesions characterized by vascular sclerosis, cell atrophy or hyperplasia, progressive interstitial fibrosis, inclusion bodies containing lead acetate and glomerular sclerosis were found in the kidneys. The lesions found in the lungs consisted of destructuring of the parenchyma, impregnation with lead acetate, formation of fibrosis, extravasation of vascular fluids, reduction of the alveolar spaces and formation of alveolar edema. These changes were correlated with the level of lead acetate absorption, as determined using atomic spectrophotometry.

El plomo es un metal pesado utilizado en la industria. El envenenamiento debido a la exposición prolongada por plomo es una enfermedad profesional conocida por muchos años. La toxicidad del plomo es muy expresiva y puede poner en peligro el modelo estructural y funcional de los órganos y sistemas. El objetivo de este estudio fue examinar los pulmones y riñones de fetos de ratas Wistar expuestos al acetato de plomo. En este estudio, 20 fetos de ratas Wistar previamente tratados con acetato de plomo durante la gestación, tuvieron sus órganos disecados, fijados, incluidos en parafina y teñidos con hematoxilina y eosina. Macroscópicamente, los órganos fetales tratados por este metal fueron comparados con los órganos de fetos controles en relación a forma, color y consistencia. Microscópicamente, se encontraron lesiones en el riñón que se caracterizaron por esclerosis vascular, atrofia o hiperplasia de células, fibrosis intersticial progresiva, presencia de cuerpos de inclusión que contenían acetato de plomo y esclerosis glomerular. En el pulmón se observó desorganización del parénquima impregnado con acetato de plomo, formación de fibrosis, líquido intersticial, reducción de los espacios alveolares y edema alveolar. Estos cambios se correlacionaron con el nivel de absorción de acetato de plomo, determinado por espectrometría atómica.

Surface sediments from the River São Francisco were analyzed to investigate the impact, due to the presence of metals (Cd, Cu, Pb, Zn) in wastes from a metallurgical industry in the city of Três Marias/MG, Brazil. The concentrations and geochemical associations of Pb, Zn and trace metals associated with the minerals employed in zinc production were measured. Sediments close to discharge locations were highly contaminated with Pb (332-512 μg g-1) and Zn (7872-10780 μg g-1), with values decreasing rapidly due to dilution and hydraulic sorting. Evaluation of toxicity according to the Consensus-based Sediment Quality Guidelines indicated for Cd, Pb and Zn a high probability of adverse effects on aquatic biota at these sites.