Phosphorus enriched effluents increase eutrophication risks for mangrove systems in northeastern Brazil.

Discharge of effluents loaded with phosphorus (P) from anthropogenic activities constitutes serious eutrophication risks in marine and terrestrial ecosystems, including mangroves. Three mangroves in NE-Brazil were studied to evaluate the impact of P-rich-effluents from shrimp farming and domestic sewage, in relation to a control area (natural mangrove). Soil phosphorus fractionation and water chemical analysis were performed to assess potential pollution. We observed the most labile P forms increased gradually and significantly from control to sewage to shrimp farm impacted mangroves as observed by increasingly dissolved orthophosphate (PO43-) content in water and the exchangeable/soluble P (Exch-P) extracted from soils, which is supported by the discriminant analysis. Exch-P results were correlated to Humic-Acid-P, which can release more labile P forms when mineralized. Our results demonstrate a substantial impact of aquiculture and sewage effluents in mangroves at both organic and inorganic P fractions, raising important concerns regarding pollution for these marine ecosystems.

Biofloc production in activated sludge system treating shrimp farming effluent / Produção de bioflocos em sistema de lodos ativados tratando efluente de carcinicultura

ABSTRACT The release of wastewater and the shrimp feed cost are the main challenges faced by the shrimp farming industry. An alternative solution to both problems is biofloc production in a unit external to the farm, in an activated sludge system for effluent treatment. The treatment system's influent was composed of the shrimp farm wastewater supplemented with urea and sugarcane molasses. The results show that the average removal of chemical oxygen demand was 71% and the average biofloc production in the reactor was approximately 1.5g.L-1. Adding molasses to the influent contributed to the increase in the quantity and diversity of existing microorganisms that are beneficial to cultured shrimp. The mass balance of nitrogen compounds confirmed that nitrification occurred in the system. Therefore, the use of the activated sludge system is a viable and environmentally suitable alternative to produce bioflocs and shrimp farming effluent treatment.

RESUMO A geração de efluentes e o custo com a alimentação do camarão são os principais desafios enfrentados pela carcinicultura. Uma solução conjunta para ambos os problemas é a produção de bioflocos em um sistema de lodo ativado para tratamento de efluentes. Neste trabalho, o afluente ao sistema estudado era composto pelas águas residuais do cultivo de camarão suplementadas com ureia e melaço de cana-de-açúcar. Os resultados mostraram que a remoção média de demanda química de oxigênio foi de 71% e a produção média de bioflocos no reator foi de aproximadamente 1,5 g.L-1. A adição de melaço ao afluente contribuiu para o aumento da quantidade e da diversidade de microrganismos benéficos para a produção de camarão. Houve remoção de amônia e nitrificação confirmada pelo balanço de massa. Portanto, a utilização do sistema de lodos ativados é uma alternativa viável e ambientalmente adequada para produzir bioflocos e tratar efluentes de cultivo de camarão.

Facilitation as Attenuating of Environmental Stress among Structured Microbial Populations.

There is currently an intense debate in microbial societies on whether evolution in complex communities is driven by competition or cooperation. Since Darwin, competition for scarce food resources has been considered the main ecological interaction shaping population dynamics and community structure both in vivo and in vitro. However, facilitation may be widespread across several animal and plant species. This could also be true in microbial strains growing under environmental stress. Pure and mixed strains of Serratia marcescens and Candida rugosa were grown in mineral culture media containing phenol. Growth rates were estimated as the angular coefficients computed from linearized growth curves. Fitness index was estimated as the quotient between growth rates computed for lineages grown in isolation and in mixed cultures. The growth rates were significantly higher in associated cultures than in pure cultures and fitness index was greater than 1 for both microbial species showing that the interaction between Serratia marcescens and Candida rugosa yielded more efficient phenol utilization by both lineages. This result corroborates the hypothesis that facilitation between microbial strains can increase their fitness and performance in environmental bioremediation.

Preliminary analysis on the use of Trophic State Indexes in a brazilian semiarid reservoir / Análise preliminar sobre uso de Índices de Estado Trófico em um reservatório do semiárido brasileiro

The Carlson's (1977) Trophic State Index (TSI) is a widely employed tool to estimate the degree of eutrophication in a reservoir. In Brazil, the need of a classification system that would take into account regional characteristics employed adjusted indexes generated by data from reservoirs in the southeastern region of the country. Current research compares responses for Carlson's TSI (1977) and its derivations for Brazilian reservoirs from data collected in the Pereira de Miranda Reservoir (State of Ceará, Brazil), and analyzes the influence of local conditions on results and their applicability to reservoirs in the semiarid region. TSIs were calculated by data on total phosphorus, chlorophyll a and water transparency. The reservoir was estimated as mesotrophic based on the chlorophyll a variable, and between eutrophic and hyper-eutrophic when based on total phosphorus data and water transparency. Results showed the need to consider intrinsic factors in the discussion on the applicability of TSIs to reservoirs in the semiarid region since the peculiar hydro-climatic conditions and morphometric characteristics make them even more vulnerable to disturbance agents, such as winds which have a significant influence on processes that determine the trophic state.

O índice de estado trófico (IET) de Carlson (1977) é uma ferramenta muito utilizada para estimar o grau de eutrofização de reservatórios. No Brasil, a necessidade de um sistema classificatório que levasse em consideração as peculiaridades regionais resultou em derivações do índice original. O objetivo desta pesquisa foi comparar as respostas do IET de Carlson (clima temperado) e dos índices modificados para reservatórios do sudeste brasileiro (clima subtropical) originadas para dados do açude Pereira de Miranda e analisar a influência das condições locais sobre esses resultados, discutindo-se a sua aplicabilidade para a região semiárida do Brasil. Os índices de estado trófico foram calculados a partir dos valores de clorofila a, fósforo total e transparência da água. O estado trófico do açude foi estimado como mesotrófico, com base na variável clorofila a, e entre eutrófico e hipereutrófico, com os dados de fósforo total e de transparência da água. A partir dos resultados, observa-se a necessidade de considerar fatores intrínsecos na discussão sobre a aplicabilidade desses índices para os reservatórios do semiárido, especialmente quando as variáveis hidroclimáticas e morfométricas os tornam ainda mais vulneráveis a distúrbios, a exemplo do vento, que tem influência significativa sobre os processos que determinam o estado trófico

Cumulative influences of a small city and former mining activities on the sediment quality of a subtropical estuarine protected area.

This study aimed to evaluate the sediment quality in the estuarine protected area known as Cananéia-Iguape-Peruíbe (CIP-PA), located on the southeastern coast of Brazil. The study was designed considering possible negative effects induced by the city of Cananéia on the sediment quality of surrounding areas. This evaluation was performed using chemical and ecotoxicological analyses. Sediments were predominantly sandy, with low CaCO3 contents. Amounts of organic matter varied, but higher contents occurred closer to the city, as well as did Fe and Total Recoverable Oils and Greases (TROGs) concentrations. Contamination by Cd and Cu was revealed in some samples, while concentrations of Zn were considered low. Chronic toxicity was detected in all tested sediments and acute toxicity occurred only in sediments collected near the city. The principal component analysis (PCA) revealed an association among Cd, Cu, Fe, TROG, fines, organic matter, CaCO3, and chronic toxicity, whereas acute toxicity was found to be associated with Zn and mud. However, because Zn levels were low, acute toxicity was likely due to a contaminant that was not measured. Results show that there is a broad area within the CIP-PA that is under the influence of mining activities (chronic toxicity, moderate contamination by metals), whereas poorer conditions occur closer to Cananéia (acute toxicity); thus, the urban area seems to constitute a relevant source of contaminants for the estuarine complex. These results show that contamination is already capable of producing risks for the local aquatic biota, which suggests that the CIP-PA effectiveness in protecting estuarine biota may be threatened.

Efeito do fenol sobre células de Pseudomonas aeruginosa ATCC 25619 livres e imobilizadas em espuma de poliuretano / Effect of phenol on free and immobilized cells of Pseudomonas aeruginosa ATCC 25619 in polyurethane foam

A imobilização de micro-organismos sobre superfícies sólidas é uma estratégia recente para tratamento de substâncias químicas tóxicas e recalcitrantes, minimizando o impacto do descarte no ambiente. Assim, este trabalho teve por objetivo, comparar o efeito do fenol sobre células de Pseudomonas aeruginosa livres e imobilizadas em espuma de poliuretano. Foram testados dois tipos de espuma de poliuretano e duas concentrações do meio de cultura. À retenção celular foi avaliada por meio da contagem de células viáveis aderidas ao poliuretano, em intervalos de tempo fixos por 24 h. Subsequentemente, células livres em suspensão e imobilizadas foram imersas em meio mineral contendo fenol como única fonte de carbono e energia. Contagens de células viáveis foram realizadas diariamente para avaliar o efeito do fenol. O número de células retidas foi semelhante nos dois tipos de espuma, sendo significativamente maior no meio de cultura mais concentrado. O efeito do fenol sobre as células imobilizadas foi menos severo que sobre as células livres. Os resultados obtidos nas condições experimentais sugerem que a imobilização celular sobre espuma de poliuretano de 16 e 23 kg.m-3 em caldo Luria-Bertani pode ser usada como ferramenta no tratamento biológico de ambientes poluídos com fenol.

The microbial immobilization on solid surfaces is a recent strategy for treatment of recalcitrant toxic chemicals minimizing the environmental impact of disposal. This study aimed, immobilize the bacteria Pseudomonas aeruginosa ATCC 25619 in polyurethane foam and compare the effect of phenol on the free and immobilized cells. Two types of polyurethane foam and two concentrations of the culture medium were tested. The cell retention was evaluated by counting of viable cells adhered to the polyurethane in fixed time intervals for 24 h. Subsequently, cells in suspension and immobilized were immersed in mineral medium containing phenol as the sole source of carbon and energy. Viable cell counts were taken daily to assess the effect of phenol. The number of cells retained was similar for both types of foam, being significantly higher in the culture more concentrated. The effect of phenol on the immobilized cells was less severe than on the free cells. The results obtained in the experimental conditions suggest that cell immobilization on polyurethane foam of 16 and 23 kg.m-3 in Luria-Bertani broth can be used as a tool in the biological treatment of polluted environments with phenol.

Influence of rainfall on the trophic status of a Brazilian semiarid reservoir / Influência da chuva no estado trófico de um reservatório do semiárido brasileiro

This study evaluated the trophic conditions of the reservoir located in the urban perimeter of the town General Sampaio, semiarid region of the Ceará State, Brazil and its relationship with seasonal variation in rainfall between 2010 and 2011. It was obtained data for Secchi disk transparency, total phosphorus, and chlorophyll a to calculate the Trophic State Index (TSI), as well as rainfall data. The Trophic State Index (TSI) proposed by Carlson (1977) and modified by Toledo Junior (1990) was used to test the influence of the seasonal variation in rainfall on hydrological variables and on trophic conditions of the reservoir in 2010 and 2011. There was seasonal variability in variables analyzed between climatic periods (rainy and dry) and trophic conditions determined through the trophic index indicated conditions ranging from oligotrophic to eutrophic during the two years analyzed in this reservoir. Under these circumstances, one may conclude that the trophic status is related to seasonal fluctuations in the hydrology of the system controlled by rainfall, which is a common feature of semiarid regions.

Este estudo buscou avaliar as condições tróficas do reservatório situado no perímetro urbano da cidade de General Sampaio, semiárido do Estado do Ceará, Brasil e sua relação com a variação sazonal das chuvas nos anos 2010 e 2011. Foram obtidos dados de transparência do disco de Secchi, fósforo total e clorofila a para calcular o Índice de Estado Trófico (IET), em paralelo com os dados pluviométricos. Foi utilizado o Índice de Estado Trófico (IET), proposto por Carlson (1977), modificado por Toledo Junior (1990), para testar se a variação sazonal de chuva alterou significativamente as variáveis hidrológicas e as condições tróficas das águas do reservatório nos anos 2010 e 2011. Houve variabilidade sazonal nas variáveis analisadas entre os períodos climáticos (chuvoso e seco) e as condições tróficas determinadas por meio do índice trófico indicaram a presença de condições oligotróficas variando as condições eutróficas durante os anos analisados neste reservatório. Conclui-se que o estado trófico deste reservatório está relacionado com as flutuações sazonais na hidrologia do sistema controlado pela chuva, que é uma característica comum de regiões semiáridas.

Efeito da toxicidade de Cr (VI) e Zn (II) no crescimento do fungo filamentoso Aspergillus niger isolado de efluente industrial / Toxicity effect of Cr (VI) and Zn (II) on growth of filamentous fungi Aspergillus niger isolated from industrial effluent

Processos convencionais de tratamento de efluentes utilizam microrganismos vivos, o que sugere limitações relativas À toxicidade de metais para os microrganismos. O experimento consistiu em adicionar soluções monoelementares de Cr (VI) e Zn(II) em diferentes concentrações (0, 20, 50, 100, 200, 300, 400, 500 mg.L-1) ao meio de crescimento e observar a influência dos metais no crescimento micelial e germinativo do fungo Aspergillus Níger por verificação visual da expansão radial do micélio e da germinação de esporos, seguida de registro fotográfico. Os resultados mostraram que o metabolismo do fungo foi completamente inibido em concentrações acima de 500 mg Zn (II).L-1 e 150 mg Cr (VI).L-1. O ED50 (concentração de ingrediente ativo capaz de inibir 50 por cento do crescimento micelial do fungo) para os dois íons metálicos, nas condições estudadas, está na faixa entre 100 e 150 mg.L-1. Palavras-chave: metais pesados; inibição; crescimento micelial; Aspergillus niger; ED50.

Many standard processes of wastewater treatment use live microorganisms, which suggests limitations on a metal toxicity to the microorganism. The experiment consisted in adding mono elementary solutions of Cr (VI) and Zn (II) at different concentrations (0, 20, 50, 100, 200, 300, 400, 500 mg.L-1) to the growth mean, and to observe the influence of metals on mycelial and germinative growth of the Aspergillus niger fungus, by means of visual observation of the radial expansion of the mycelius and the germination of spores, followed by photograph registration. The results showed that the metabolism of the fungus was completely inhibited at concentrations above 500 mg Zn (II).L-1 and 150 mg Cr (VI).L-1. The ED50 (concentration of active ingredient capable of inhibiting 50 percent of mycelial growth of the fungus) for both metal ions, under the studied conditions, is in the range between 100 and 150 mg.L-1.

Tratamento de efluentes de refinaria de petróleo em reatores com Aspergillus niger / Treatment of petroleum refinery wastewater by reactors inoculated with Aspergillus niger

Neste trabalho, avaliou-se o efeito do tempo de detenção hidráulica (TDH) no desempenho de três reatores aeróbios inoculados com Aspergillus niger AN400, usados para tratamento de efluentes de refinarias de petróleo. Cada reator foi operado com um tempo de detenção hidráulica diferente: 4, 8 e 12 horas, durante 152 dias. Eles possuíam leito fixo de espuma de poliuretano e o escoamento era ascendente e contínuo. Determinaram-se: pH, fenóis, demanda química de oxigênio (DQO), amônia, nitrito e nitrato, no afluente e efluentes dos reatores. O TDH de oito horas foi o melhor para remoção de DQOsolúvel e não houve diferença entre os TDHs para remoção de fenóis totais. No período estável não houve remoção de nitrato; no entanto ocorreu remoção de nitrito de aproximadamente 99 por cento. Além disto, houve produção de amônia devido à amonificação a partir do nitrito presente no meio.

This paper evaluated the effect of hydraulic retention time (HRT) on the performance of three upflow aerobic reactors, with polyurethane foam as support material, inoculated with Aspergillus niger AN400, used for the treatment of petroleum refinery wastewater. Each reactor was operated with a different HRT: 4, 8 and 12 hours, during 152 days. The performance was evaluated based on pH; phenols; COD, nitrate and nitrite. The results show that for the COD removal, it is more reasonable to operate the reactor with HRT of eight hours. However, there was no difference among results of phenol removal efficiency of the different HRTs. During steady state condition, nitrite was removed in approximately 99 percent, but there was no reduction on the nitrate concentration. Ammonia was produced in all reactors, probably due to ammonification of nitrite.

Isolation and characterization of phenol-degrading yeasts from an oil refinery wastewater in Brazil.

This study investigated the aerobic degradation of phenol by yeast strains isolated from an oil refinery wastewater from the Northeast of Brazil. The samples displayed low fungal diversity, as only yeast colonies were detected on Sabouraud dextrose agar containing chloramphenicol 0.05% (w/v). Among the isolates, three yeast strains were selected to be evaluated for their potential for degrading high phenol concentrations. These species were identified through morphological and biochemical characteristics as Candida tropicalis, C. rugosa, and Pichia membranaefaciens. Although the strains were able to degrade the phenol concentration present in the wastewater, which was 7 mg l(-1), only C. tropicalis was capable of growing at high concentrations of phenol such as 500 mg l(-1 )and 1,000 mg l(-1) in a mineral medium containing this pollutant as the only carbon source. C. rugosa and P. membranaefaciens were inhibited in the presence of 500 mg l(-1) of phenol. However, a longer incubation time was needed for C. tropicalis strain to degrade 1,000 mg l(-1) of phenol compared to the time required to degrade 500 mg l(-1). Moreover, the strain released a significant amount of polysaccharide biosurfactant in the medium probably to minimize the toxic effect of the high phenol concentration. When challenged with 1,500 and 2,000 mg l(-1 )of phenol, C. tropicalis was unable to grow at the tested conditions. The results indicate that this strain of C. tropicalis can be considered both a good phenol-degrader and biosurfactant-producer. Application of this strain might be useful in bioremediation activities or treatment of phenol-polluted wastewater.

Influência da glicose sobre o consumo de fenol por Aspergillus niger an 400 em reatores em batelada / The influence of glucose on the phenol consumption by Aspergillus niger an 400 in batch reactors

Aspergillus niger AN 400 foi inoculado em reatores em batelada para remoção de fenol de meio sintético, na presença e ausência de glicose. O experimento possuía: 5 reatores de controle (grupo 1) com meio contento apenas fenol; 5 reatores (grupo 2) inoculados com fungos e com meio com fenol e sem glicose; e 5 reatores (grupo 3) inoculados com fungos e com meio com fenol e glicose (5 g/L). Os reatores foram agitados a 200 rpm, a 30ºC, durante 5 dias. A concentração média inicial de fenol foi de 323 mg/L e a de matéria orgânica, de 696 mg DQO/L, meio sem glicose, e 6058 mg DQO/L, meio com glicose. Os reatores do grupo 2 removeram 48 por cento de fenol e 21 por cento de DQO, enquanto que os reatores do grupo 3, 100 por cento de fenol e 93 por cento de matéria orgânica. Não houve redução significativa de fenol e de DQO nos reatores de controle. A assimilação foi a via principal de remoção de fenol.

Batch reactors were inoculated with Aspergillus niger AN 400 to remove phenol from synthetic media with and without glucose. The experiment was set by: five blank reactors (group 1) with media containing only phenol; five reactors (group 2) inoculated with fungi and with media containing only phenol; and five reactors (group 3) inoculated with fungi and with media containing phenol and glucose (5 g/L). These reactors were kept at 30ºC under stirring of 200 rpm during 5 days. The mean initial concentrations of phenol and COD were 323 mg/L and 696 mg COD/L for the media without glucose, and 6058 mg COD/L for the media containing glucose. The reactors of group 2 removed 48 percent of phenol and 21 percent of COD, while the reactors of group 3 removed 100 percent of phenol and 93 percent of COD. There was no significant reduction of phenol and COD in the blank reactors. The assimilation was the main pathway of phenol removal.

Influência do tempo de detenção hidráulica em um sistema UASB seguido de um reator biológico com fungos para tratar efluentes de indústria de castanha de caju / Influence of the time of detention hidraulic of a sistem UASB followed by a biological reactor with fungi to treat efluent of cashew nut industry

Nesta pesquisa, estudou-se a influência do tempo de detenção hidráulica (TDH) em um sistema constituído de um reator anaeróbio tipo UASB seguido de um reator biológico com fungos (RBF) para tratar efluente de uma indústria de beneficiamento de castanha de caju. O presente trabalho foi dividido em uma fase de fluxo descontínuo (batelada) e uma fase de fluxo contínuo (UASB - RBF), que constituiu-se de sete etapas ( 8h e 2h, 8h e 1h, 4h e 8h, 4h e 6h, 4h e 4h, 4h e 2h e 4h e 1h), onde foi avaliada a influência do TDH na remoção de: DQO (Demanda Química de Oxigênio), amônia, nitrato e ortofosfato. Uma combinação que apresentou melhores resultados, foi a etapa de 4h (TDH do reator UASB) e 2h (TDH do RBF), apresentando remoções de: 93,8 por cento de DQO, 86,7 por cento de nitrato, 38,3 por cento de amônia e 16 por cento de ortofosfato.