Characterization of dissolved organic matter in an urbanized estuary located in Northeastern Brazil.

The Sal River estuary, which is located in the state of Sergipe, Northeastern Brazil, stands out as an urban estuary, anthropogenically impacted by untreated and treated wastewater discharge. Synchronous fluorescence spectroscopy and measurement of dissolved organic carbon (DOC) were used for characterization of dissolved organic matter (DOM) in the estuarine water. Dissolved organic carbon concentrations ranged from 7.5 to 19.0 mg L-1 and, in general, the highest values were recorded during dry season. For both seasons (dry and rainy), DOC presented an inverse linear relationship with salinity, which indicates a conservative dilution of organic matter coming into the estuary. During rainy season, anthropogenic organic constituents and humic substances from land-based sources predominated in DOM composition, carried by river flow. Whereas during the dry season, it has been observed a significant increase of products generated by microbial degradation of anthropogenic organic matter. The relationships between fluorescence intensity and salinity suggest a conservative behavior during rainy season and a non-conservative behavior during dry season, with addition of fluorescent organic matter into the intermediate zone of the estuary. Photodegradation by action of sunlight caused a decrease in fluorescence intensity of humic and tryptophan-like constituents and the release of photoproducts, resulting in an increase in fluorescence intensity of protein-like constituents.

Assessment of trace metals pollution in estuarine sediments using SEM-AVS and ERM-ERL predictions.

This paper presents the distributions of the investigation of trace metals geochemistry in surface sediments of the Sergipe river estuary, northeast Brazil. Analyses were carried out by Flame or electrothermal atomic absorption spectrometry (FAAS or ETAAS). Principal component analysis was applied to results to identify any groupings among the different sampling sites. In order to determine the extent of contamination, taking into account natural variability within the region, metal concentrations were normalized relative to aluminium. Cr, Cu, Ni and Zn contamination was observed in sediments from the area receiving highest inputs of domestic wastes, while cadmium contamination occurred in sediments from the region affected by highest inflows of industrial effluents. Possible toxicity related to these metals was examined using the relationship simultaneously extracted metals/acid volatile sulfide and by comparing sediment chemical data with sediment quality guidelines ERL-ERM values. Results obtained using the two methods were in agreement and indicated that adverse effects on aquatic biota should rarely occur.

Multivariate Optimization of Conditions for Digestion of Wet Feeds for Dogs and Cats Using a Closed Digester Block and Multielement Determination by ICP-OES.

A full 24 factorial design was applied to find the best combination of diluted reagents (HNO3 and H2O2), time, and temperature for the digestion of samples of wet feed for dogs and cats using a closed digestion block. The residual carbon concentration (RCC) was used as the response in the factorial design. All variables and their interactions significantly influenced the digestion of the feed samples, as indicated by the RCC. The conditions established for the digestion of 0.05 g (dry mass) wet feed samples were the addition of 3.0 mol/L HNO3 and 5.0% m/m H2O2 in a final volume of 10 mL, followed by heating in a closed digestion block at a temperature of 170°C for 120 min. Analyses were performed by inductively coupled plasma (ICP) optical emission spectrometry (OES). LOQs ranged from 0.2 µg/g (Mg and Sr) to 51 µg/g (P). Accuracy of the analytical method was confirmed through the analysis of the Standard Reference Materials Tomato Leaves (NIST 1573), Apple Leaves (NIST 1515), and Peach Leaves (NIST 1547). The agreement values achieved ranged from 80.2 ± 0.3% for Ba to 113.8 ± 7.1% for Zn (n = 3). Addition and recovery tests were carried out by adding the analytes to a feed sample at two concentration levels, and the recoveries were between 84 ± 6 and 114 ± 10% for macroelements (Ca, K, Mg, and P; n = 3) and between 88 ± 3 and 113 ± 7% for microelements and trace elements (B, Cu, Fe, Sr, and Zn; n = 3). The precision values achieved for the different elements, expressed as RSDs, were better than 7.3% (Zn; n = 3) except for Cu determination, that was 14.6% (n=3). The optimized analytical method was applied to 10 commercial samples of wet feed for cats and dogs, with the concentrations of Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, P, Sr, and Zn determined by ICP-OES.

The piscine micronucleus test to assess the impact of pollution on the Japaratuba river in Brazil.

In situ investigations of the effects of mutagenic pollutants (environmental monitoring) have increasingly used bioindicators, and fish often have been used in these studies as sentinel organisms. In the present study, we have used the piscine micronucleus test (MNT) as an in situ biological indicator of chemical contamination in two fresh water fish species (Astyanax bimaculatus and Hoplias malabaricus). The fish were collected from two sites (Sites 1 and 2) in the Japaratuba River (Sergipe, Brazil), in an area impacted by a petrochemical industrial complex which indirectly contributes treated effluent (produced water) to the river. Responses in fish from these sites were compared to fish from a clean reference site (Jacarecica River - Sergipe, Brazil). The results indicated an enhanced frequency of micronuclei (MN) in peripheral red blood cells of A. bimaculatus collected at Sites 1 and 2 when compared to their respective negative control (A. bimaculatus collected from the Jacarecica River). H. malabaricus collected at Sites 1 and 2 did not have a significant increase in MN. The results of this study indicate that the piscine MNT is a useful in vivo technique for the detection of chemical contaminants in the aquatic environment and that the assay shows potential for in situ monitoring of water quality. Nevertheless, the results also demonstrated differential sensitivity of A. bimaculatus and H. malabaricus to the induction of MN.

Multivariate optimization of an analytical method for the analysis of dog and cat foods by ICP OES.

Experimental design methodology was used to optimize an analytical method for determination of the mineral element composition (Al, Ca, Cd, Cr, Cu, Ba, Fe, K, Mg, Mn, P, S, Sr and Zn) of dog and cat foods. Two-level full factorial design was applied to define the optimal proportions of the reagents used for microwave-assisted sample digestion (2.0 mol L(-1) HNO3 and 6% m/v H2O2). A three-level factorial design for two variables was used to optimize the operational conditions of the inductively coupled plasma optical emission spectrometer, employed for analysis of the extracts. A radiofrequency power of 1.2 kW and a nebulizer argon flow of 1.0 L min(-1) were selected. The limits of quantification (LOQ) were between 0.03 µg g(-1) (Cr, 267.716 nm) and 87 µg g(-1) (Ca, 373.690 nm). The trueness of the optimized method was evaluated by analysis of five certified reference materials (CRMs): wheat flour (NIST 1567a), bovine liver (NIST 1577), peach leaves (NIST 1547), oyster tissue (NIST 1566b), and fish protein (DORM-3). The recovery values obtained for the CRMs were between 80 ± 4% (Cr) and 117 ± 5% (Cd), with relative standard deviations (RSDs) better than 5%, demonstrating that the proposed method offered good trueness and precision. Ten samples of pet food (five each of cat and dog food) were acquired at supermarkets in Aracaju city (Sergipe State, Brazil). Concentrations in the dog food ranged between 7.1 mg kg(-1) (Ba) and 2.7 g kg(-1) (Ca), while for cat food the values were between 3.7 mg kg(-1) (Ba) and 3.0 g kg(-1) (Ca). The concentrations of Ca, K, Mg, P, Cu, Fe, Mn, and Zn in the food were compared with the guidelines of the United States' Association of American Feed Control Officials (AAFCO) and the Brazilian Ministry of Agriculture, Livestock, and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento-MAPA).

Saúde ambiental: contaminação das águas dos estuários dos rios do Sal, Sergipe e Poxim / Environmental Health - Contamination of Estuary Waters in the Sal, Sergipe and Poxim Rivers

Entre as substâncias tóxicas que chegam aos ecossistemas aquáticos, os poluentes orgânicos levados diretamente por despejo de efluentes ou transportados indiretamente pela chuva merecem especial interesse, devido à eutrofização que geralmente provocam em corpos hídricos. Ultimamente, em virtude do crescimento populacional e da intensificação das atividades humanas que envolvem estes poluentes, a concentração de matéria orgânica tem aumentado de forma generalizada nos corpos d´água, em níveis que ameaçam a biota aquática e também os organismos terrestres que dela se suprem, incluindo o próprio homem. Neste trabalho, a qualidade das águas dos estuários dos rios do Sal, Sergipe e Poxim foi analisada em relação às concentrações do surfactante LAS (dodecil benzeno sulfonato de sódio) e de amônia, nitrito, nitrato, fosfato, salinidade, cloreto, alcalinidade, oxigênio dissolvido e pH, com o uso da metodologia de Standard Methods for the Examination of Wastewater (1998). Foram coletadas amostras de água na superfície e no fundo em 20 estações de amostragem para a realização das análises em laboratório, além das medidas feitas in situ de um conjunto de variáveis físicas e químicas. Os resultados revelaram que as concentrações de LAS, amônia, fosfato, nitrito e nitrato foram altas em determinadas estações. As concentrações variaram entre 0,01 a 7,92 mg.L. para LAS; de 0,12 a 0,974 mg.L para amônia; de 0,002 a 0,14 mg.L para nitrito; de 0,001 a 0,337 mg.L para nitrato, de 0,91 a 201 mg.L para fosfato; de 0,75 a 8,00 mg.L para oxigênio dissolvido. A alcalinidade e o cloreto situaram-se entre 197,60 e 596 mg.L e 2293,8 a 35689,0 mg.L respectivamente. Já o pH e a salinidade variaram de 7,0 a 8,0 e de 2,4 a 32,6 por cento. As concentrações de fosfato variaram de médias a altas, caracterizando condições de mesotrofia e hipereutrofia. Os resultados obtidos com este estudo demonstram claramente a situação de degradação em que se encontram as águas dos rios Poxim, Sergipe e do Sal na região urbana de Aracaju. Em decorrência do adensamento urbano e industrial da cidade, verifica-se, portanto, a necessidade de um monitoramento constante da região, considerando-se as variações espaciais e temporais dos processos de poluição orgânica.

Saúde ambiental: emprego de Poecilia Vivipara e Artemia Salina para determinar a toxicidade aguda para água de produção de petróleo caracterizada no Estado de Sergipe / Environmental Health - Application of Poecilia Vivipara and Artemia Salina to Determine Acute Toxicity of Water for Petroleum Production in the State of Sergipe

Há muito que diversas espécies de organismos são reconhecidas como grupos sensíveis a variaçãoes de parâmetros ambientais. Os critérios de qualidade da água para esses animais são derivados principalmente de testes de laboratório e, em escala muito menor, de ensaios realizados em campo. O emprego de testes de toxicidade aguda para água de produção de petróleo permite avaliar possíveis impactos que às vezes a simples caracterização física e química da água não revela. Sabe-se que essa constatação, isoladamente, não é suficiente para definir a toxicidade das substâncias, uma vez que pode haver processos sinérgicos e antagônicos. Os testes de toxicidade aguda foram realizados com duas espécies, um peixe nativo, Poecilia vivipara, e um crustáceo, Artemia salina. O método para o desenvolvimento desses testes foi baseado na 16ª edição de "Standard Methods for Examination of Water and Watewater". Determinaram-se ainda neste trabalho as concentraçãoes de HPAs e metais pesados existentes na água produzida.

Utilização do camarão sete-barbas (Xiphopenaeus Kroyeri) na determinação da toxicidade da água de produção de petróleo caracterizada no Estado de Sergipe / Use of Atlantic seabob (Xiphopenaeus Kroyeri) for determining toxicity of water used for characterized oil production in the State of Sergipe

Foram avaliadas as características físico-químicas e a toxicidade da água de produção de petróleo caracterizada no Estado de Sergipe, sobre juvenis do camarão-sete-barba (Xiphopenaeus Kroyeri), expostos a diferentes diluições efluente, por períodos de até 96 horas, tendo em vista a larga distribuição, grande importância econômica ecológica dessa espécie, e os problemas de poluição aos quais as regiões costeiras produtoras de petróleo estão sujeitas. Foram utilizadas 315 juvenis capturados no ambiente e deixados aclimatar por trinta dias em laboratório. O peso médio dos animais em cada aquário ficou entre 1,07 e 1,44 gramas, apresentando comprimentos entre 12, 54 e 15,29 mm. Três replicas de 15 indivíduos foram submetidas a uma das seguintes diluições: 0,0 (controle), 1,0 por cento, 6,2 por cento, 12,5 por cento, 25 por cento e 50 por cento. Os indivíduos mortos foram retirados do aquário e contados às: 24,48, 72 e 96 horas de exposição à água produção de petróleo. As CL50 encontradas foram em média de 20,23 por cento, para exposição de 24 horas; 13,12 por cento para 48 horas, 8,31 por cento para 72 horas e 4,73 por cento para 96 horas. Determinou-se ainda neste trabalho as concentrações de HPAs (Hidrocarbonetos poliaromáticos) e metais pesados existentes na água produzida. Os resultados de HPs demonstraram predominância para o naftaleno (26,68mg/L),já para metais pesados as concentrações foram bem baixas.Os resultados demonstraram claramente que mesmo em pequenas concentrações a água de produção é toxica para o X. kroyeri.