A malacological survey in the Manso Power Plant, State of Mato Grosso, Brazil: new records of freshwater snails, including transmitters of schistosomiasis and exotic species

Introduction Schistosomiasis is a parasitic disease of public health concern in Brazil, and the construction of hydroelectric dams, in addition to increasing permanent human settlement and tourism, has created conditions suitable for the establishment of mollusks that can transmit schistosomiasis. Such areas require a number of actions to prevent the establishment of schistosomiasis. This paper reports on a freshwater malacological survey carried out in the geographical area of the Manso Power Plant. Methods Mollusks were collected in 18 municipalities in the State of Mato Grosso between February 2002 and February 2004 (qualitative study) and from April 2009 to February 2011 (quantitative study). Results Thirty-one species of mollusks were collected, including newly recorded species (Antillorbis nordestensis and Burnupia ingae). In addition, the geographic distributions of known species, including Biomphalaria straminea, a snail vector of Schistosoma mansoni, were expanded. A total of 4,507 specimens were collected in the APM Manso reservoir (Usina Hidrelétrica de Aproveitamento Múltiplo de Manso) during the quantitative study, and Biomphalaria amazonica was found in six of the 10 localities analyzed. The Afroasiatic species Melanoides tuberculata, introduced after February 2009, was the dominant species (relative abundance 94.96%). Conclusions The study area is epidemiologically important due to the occurrence of B. straminea and B. amazonica, which are vectors of schistosomiasis, and M. tuberculata, a snail host of Centrocestus formosanus, which is responsible for centrocestiasis transmission. Observations of M. tuberculata and the exotic freshwater clams Corbicula fluminea and Corbicula largillierti raise concerns about biodiversity.

Impact of a power plant cooling system on copepod and meroplankton survival (Bahía Blanca estuary, Argentina)

The impact of a power plant cooling system in the Bahía Blanca estuary (Argentina) on the survival of target zooplanktonic organisms (copepods and crustacean larvae) and on overall mesozooplankton abundance was evaluated over time. Mortality rates were calculated for juveniles and adults of four key species in the estuary: Acartia tonsa Dana, 1849 and Eurytemora americana Williams, 1906 (native and invading copepods), and larvae of the crab Chasmagnathus granulata Dana, 1851 and the invading cirriped Balanus glandula Darwin, 1854. Mean total mortality values were up to four times higher at the water discharge site than at intake, though for all four species, significant differences were only registered in post-capture mortality. The findings show no evidence of greater larval sensitivity. As expected, the sharpest decrease in overall mesozooplankton abundance was found in areas close to heated water discharge.

RECOVERY OF AN OXISOL DEGRADED BY THE CONSTRUCTION OF A HYDROELECTRIC POWER PLANT

ABSTRACT The removal of thick layers of soil under native scrubland (Cerrado) on the right bank of the Paraná River in Selvíria (State of Mato Grosso do Sul, Brazil) for construction of the Ilha Solteira Hydroelectric Power Plant caused environmental damage, affecting the revegetation process of the stripped soil. Over the years, various kinds of land use and management systems have been tried, and the aim of this study was to assess the effects of these attempts to restore the structural quality of the soil. The experiment was conducted considering five treatments and thirty replications. The following treatments were applied: stripped soil without anthropic intervention and total absence of plant cover; stripped soil treated with sewage sludge and planted to eucalyptus and grass a year ago; stripped soil developing natural secondary vegetation (capoeira) since 1969; pastureland since 1978, replacing the native vegetation; and soil under native vegetation (Cerrado). In the 0.00-0.20 m layer, the soil was chemically characterized for each experimental treatment. A 30-point sampling grid was used to assess soil porosity and bulk density, and to assess aggregate stability in terms of mean weight diameter (MWD) and geometric mean diameter (GMD). Aggregate stability was also determined using simulated rainfall. The results show that using sewage sludge incorporated with a rotary hoe improved the chemical fertility of the soil and produced more uniform soil pore size distribution. Leaving the land to develop secondary vegetation or turning it over to pastureland produced an intermediate level of structural soil quality, and these two treatments produced similar results. Stripped soil without anthropic intervention was of the lowest quality, with the lowest values for cation exchange capacity (CEC) and macroporosity, as well as the highest values of soil bulk density and percentage of aggregates with diameter size <0.50 mm, corroborated by its lower organic matter content. However, the percentage of larger aggregates was higher in the native vegetation treatment, which boosted MWD and GMD values. Therefore, assessment of some land use and management systems show that even decades after their implementation to mitigate the degenerative effects resulting from the installation of the Hydroelectric Plant, more efficient approaches are still required to recover the structural quality of the soil.

SEASONAL DISTRIBUTION OF MALARIA VECTORS (DIPTERA: CULICIDAE) IN RURAL LOCALITIES OF PORTO VELHO, RONDÔNIA, BRAZILIAN AMAZON

We conducted a survey of the malaria vectors in an area where a power line had been constructed, between the municipalities of Porto Velho and Rio Branco, in the states of Rondônia and Acre, respectively. The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia. Mosquito field collections were performed in six villages along the federal highway BR 364 in the municipality of Porto Velho, namely Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã, and Extrema. Mosquito captures were performed at three distinct sites in each locality during the months of February, July, and October 2011 using a protected human-landing catch method; outdoor and indoor captures were conducted simultaneously at each site for six hours. In the six sampled areas, we captured 2,185 mosquitoes belonging to seven Anopheles species. Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi. An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics.

Observations on aquatic Macrophyte Dynamics In the Reservoir Of The Balbina Hydroelectric Powerplant, Amazonas State, Brazil

Between 1991 and 1995 aquatic macrophyte composition was observed in the lower part of the reservoir of the hydroelectric power plant of Balbina (Amazonas, Brazil). After closure of the dam in 1987, vegetation cover - mostly Eichhornia crassipes - was high, but was not quantified. After 1990 it declined rapidly with a characteristic succession pattern: Eichhornia ® Vincularia + Cyperaceae ® Salvinia. The Cyperaceae, and many other less dominant species, were mostly associated with drift wood, produced by the decomposing, emergent forest. Comparison of the chemical data of the Uatumã river before the construction of the dam (1983) with those of later years (1989 - 1995) suggests that the succession was the result of a relatively mild and short period of eutrophication, followed by declining nutrient levels. Annual variation of water levels, followed by aquatic and terrestrial decomposition of the marginal vegetation, may allow for the maintenance of relatively productive vegetation belts along the shore lines of islands and inundated stream valleys.

Forest structure of artificial islands in the Tucuruí dam reservoir in northern Brazil: a test core-area model

Construction of hydroelectric dams in tropical regions has been contributing significantly to forest fragmentation. Alterations at edges of forest fragments impact plant communities that suffer increases in tree damage and dead, and decreases in seedling recruitment. This study aimed to test the core-area model in a fragmented landscape caused by construction of a hydroelectric power plant in the Brazilian Amazon. We studied variations in forest structure between the margin and interiors of 17 islands of 8-100 hectares in the Tucuruí dam reservoir, in two plots (30 and >100m from the margin) per island. Mean tree density, basal area, seedling density and forest cover did not significantly differ between marginal and interior island plots. Also, no significant differences were found in liana density, dead tree or damage for margin and interior plots. The peculiar topographic conditions associated with the matrix habitat and shapes of the island seem to extend edge effects to the islands' centers independently of the island size, giving the interior similar physical microclimatic conditions as at the edges. We propose a protocol for assessing the ecological impacts of edge effects in fragments of natural habitat surrounded by induced (artificial) edges. The protocol involves three steps: (1) identification of focal taxa of particular conservation or management interest, (2) measurement of an "edge function" that describes the response of these taxa to induced edges, and (3) use of a "Core-Area Model" to extrapolate edge function parameters to existing or novel situations.

Trophic ecology of Lontra longicaudis (Carnivora, Mustelidae) in lotic and semilotic environments in southeastern Brazil

Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) is a semi-aquatic animal spread through the Central and South America, except in Chile. The implantation of a hydroelectric power plant along a river alters the dynamics of the watercourse, transforming a lotic environment into a lentic or semilotic one, what can damage the otter's feeding. From April 2008 to March 2009 we analysed the otter's food habits in lotic (streamlet) and semilotic (hydroelectric reservoir) environments of Paranapanema Valley, in southeastern Brazil. Aiming to compare the otter's diet of these two environments, we analyzed statistically the frequency of occurrence of main items in the scats. Fishes represent the base of the diet both in the reservoir and in the streamlet and, despite of the total otter's diet showing up similarities in the two environments, the results evidenced modifications on the fish species consumed between them. In the reservoir the otters ate more exotic fish Oreochromis niloticus (Linnaeus, 1758) probably because it is an easy capture prey in this place. The fact that the otters get established and feed in the reservoir doesn't mean that this structure is benefic to the species because the food supplied for it consists mainly of exotic fish species.

Células a combustível de baixa potência para aplicações estacionárias

A paradigmatic shift in developing fuel cell for stationary applications has been occurring in the last ten years. Previously, 100 kW class to a few MW class power plants were preferred but recently, the development has drifted towards units of only a few kW. The motivation is the present market situation, which favors disperse residential electric power generation from natural or liquefied gas. Membrane-type fuel cells are very promising for this application, due to their present state of development in the automobile industry. More recently, small ceramic fuel cells (SOFC) has also been found to be adequate for this application. Considering a family of 4 members, 1 kW (electric) units seem to be optimal for individual residences. This presentation discusses briefly the Brazilian scenario with respect to these units.

Análises seqüenciais de agrupamentos aplicadas ao estudo de partículas atmosféricas

The present paper has as objective to apply a sequential Cluster Analysis to the atmospheric particles: Hierarchical Cluster Analysis followed by Nonhierarchical Cluster Analysis. The hierarchical cluster analysis results were used as start point for the nonhierarchical cluster analysis as an agglomerative technique. These particles were taken from two areas of the metropolitan region of Porto Alegre, Charqueadas and Sapucaia do Sul., from may /97 to may/98, using a High Volume Sampler (Hi-Vol). Around 10,000 particles were analysed by Scanning Electron Microscope with Energy-Dispersive X-Ray microanalysis (SEM-EDS). The Hierarchical Cluster Analysis allowed the identification of five groups of particles, whose amounts were differentiated according to the summer and the winter campaigns. The abundance of each type of particles inside each group according to the different sections was verified by the Nonhierarchical Cluster Analysis, resulting in information about the emissions sources. The groups of particles of Si/Al and Si and of Fe/Zn and Fe for Charqueadas were more significant in section 2 and 3 (NW and W wind directions) and in section 1 (SE wind direction), evidencing the influence of the coal power plant and steel industry, respectively located in these quadrants. In Sapucaia do Sul the data were more heterogeneous, causing a certain difficulty to identify the source as anthropogenic. Nevertheless the group of particles containing Fe was found in sectors of NW/W wind directions which shows the influence of the steel plant.

Utilização de zeólita preparada a partir de cinza residuária de carvão como adsorvedor de metais em água

Coal ashes produced in coal-fired power plant could be converted into zeolites and can be used as low-cost adsorbents for the treatment of effluents contaminated with high levels of toxic metals. The capacity of synthetic zeolites for the removal of cadmium, zinc and copper ions from aqueous solutions has been investigated under different operating conditions. Zeolite from bottom chimney showed higher removal efficiency for metals ions than zeolite from feed hopper and mixing mill. The results indicated that the treated bottom ash could be applied in environmental technology as an immobilizer of pollutants.

Avaliação da eficiência de uma célula a combustível estacionária de ácido fosfórico

Operation and performance of a commercial PAFC power plant were analyzed. Processes influencing energy conversion efficiency were studied in each module of the fuel cell power plant. The main processes were simulated using mass and energy balance equations, and the results were validated by means of experimental data. It was concluded that the electrical efficiency is higher in comparison with microturbines. The main result achieved is a better understanding of balance of plant processes, knowledge necessary for fuel cell power plant development.

Utilização de modelagem numérica para o estudo da dispersão de poluentes emitidos pela usina termoelétrica Presidente Médici

The purpose of the present study is to evaluate the atmospheric behavior in the dispersion of the pollutants SO2, PM10 and NOx emitted by the President Medici power plant in Candiota, RS. The RAMS atmospheric model was applied and the simulations were conducted from april in 20 to 24, 2004. The concentrations of the pollutants simulated by RAMS were compared with the data measured at the air quality monitoring stations. The results showed significant influence of the emissions generated by the power plant on the concentration of the pollutants.

Biofouling e biodeterioração química de argamassa de cimento portland em reservatório de usina hidroelétrica

Last decade Brazilian rivers experimented progressive biofouling of Limnoperna fortunei communities and Cordylophora caspia hydroids. The microhabitat is so favorable that in around 1.5 years L. fortunei increased from 0.39 to nearby 149,000 units/m². Ten Portland cement mortar samples were produced with 1: 3.5: 0.4 dosages and installed for 1 year at Salto Caxias Brazilian Power Plant reservoir in 0.5 m and 1.0 m deep to investigate the biofouling influence on hydraulic civil structures. SEM, EDS, visual investigation and XRF results indicate none direct chemical interrelationships between L. fortunei and the mortar samples. However C. caspia diminished the mortar surface resistance and caused cement paste leaching.

Adsorção do corante reativo laranja 16 de soluções aquosas por zeólita sintética

Coal fly ash, a waste generated in a coal-fired electric power plant, was used to synthesize zeolite by hydrothermal treatment with NaOH solution. This zeolite was used as adsorbent to investigate the adsorption kinetics and isotherm parameters of the reactive orange 16 (RO16) dye from aqueous solutions at different concentrations (1.3-15.4 mg L-1). Three kinetic models, the pseudo-first-order, second-order, and intraparticle diffusion were used to predict the adsorption rate constants. The kinetics of adsorption of the RO16 dye followed pseudo-second-order kinetics. The adsorption isotherm data were closely fitted to the Langmuir equation. Keywords: coal fly ash; zeolite; reactive dye adsorption.

TRATAMENTO DA VINHAÇA POR ADSORÇÃO EM CARVÃO DE BAGAÇO DE CANA-DE-AÇÚCAR

The aim of this study was to develop an effective and economically viable technology for the treatment of vinasse, prior to its disposal in the soil for fertirrigation, aiming this way at reducing the environmental impacts generated by inadequately discarding this effluent. The primary treatment of vinasse by adsorption was evaluated. Adsorbents were prepared from sugar cane bagasse and their efficiency evaluated in relation to the treatment of vinasse. The process of preparation of activated carbon consisted of carbonizing bagasse at different temperatures followed by chemical activation with NaOH. The carbon samples obtained by solely carbonizing sugar cane bagasse were more efficient for removing turbidity of vinasse than samples activated with NaOH. The sample carbonized at 800 °C was the most efficient for removing turbidity of wastewater (83%). During a process of adsorption of vinasse in two stages, it was possible to obtain color removal, turbidity and COD of approximately 76, 85 and 69%, respectively. After the adsorption step of vinasse, the solid waste generated in the second stage of adsorption can be burned in the boilers of the power plant itself, affording an energy of 4606 cal g-1.