Eutrofização e capacidade de carga de fósforo de seis reservatórios a bacia do Rio Seridó, região semi-árida do Estado do RN

The eutrofization is a natural process of accumulation of nutrients in aquatic´s body that it has been accelerated for the human´s actives, mainly the related with the activities of camp, industrial and the inadequate disposition of the domestic sewage. The enrichment of the aquatic´s body with nutrients, mainly the nitrogen and the phosphorus, and the consequent proliferation of algae and Cyanobacteria can commit the quality of the water for the public provisioning, for the fish farming and for other ends. The problem becomes more critical when there is a shortage of water naturally as in the semi-arid area of the Brazilian northeast. Before that problem this work had as objective evaluates the trophic state of six reservoirs of the basin of River Seridó of Rio Grande of Norte and also estimate the capacity of load of match of the reservoir and risk probabilities based on the established limits by the resolution Conama 357/05. The results demonstrate that the six reservoirs are eutrofization, with concentration of total phosphorus and cloro a in the water upster to 50 e 12 μg l-1. The results show that space homogeneity exists in the state trophic of the reservoirs, but a significant variation interanual in function of the increase of the concentrations of nutrients and decrease of the transparency of the water with the reduction of the body of water accumulated in the reservoirs.The results of the simulation risk estocastic show that the reservoirs could receive annually from 72 to 216 Kg of P, assuming a risk of 10% of increasing in more than 30 μg l-1 the annual medium concentrations of total match in the water of these reservoirs. This load could be high in until 360 kg of P a year in case the managers assume a risk of 10% of increasing in more than 50 μg l-1 the annual medium concentrations of total phosphorus in the waters of these reservoirs

Demanda química de oxigênio, clorofila a e comunidade fitoplanctônica como indicadores da qualidade da água no Canal do Pataxó/RN

The current study examined spatial-temporal modifications and water quality through chemical and biotic indicators during both dry (January, February and November 2006) and wet seasons (March to June 2006). This study was carried out in Armando Ribeiro Gonçalves Reservoir, RN, Canal do Pataxó and after the water station treatment (WST). The physical-chemical parameters were measured in situ and inorganic nutrients, chlorophyll a and Free Oxygen Demand (FOD) were analyzed in laboratory conditions. Quali quantitative analyses of phytoplankton were carried out utilizing Sedgwick-Rafter camera. Results indicate that DQO concentrations were low. FOD concentrations in the reservoir were comparatively higher in the dry season (5.21 mgL-1; 5.64 mgL-1 e 6.05 mgL-1) in relation to the wet season (4.52 mgL-1; 4.12 mgL-1 e 4.92 mgL-1), in surface, intermediate and bottom waters, respectively. FOD values were inferior to 1.0mgL-1in both Canal do Pataxó and after WST, which is considered adequate for public use reservoirs. Although FOD concentrations were low, Armando Ribeiro Gonçalves Reservoir, Canal do Pataxó and WST were classified as euthophizied, mesotrophic ad oligotrophic, respectively, considering the Index of Trophic State Criteria. Chlorophyll a concentrations in the study reservoir were higher in the surface (199.2 µgL-1) during the wet season, whereas in Canal do Pataxó concentrations decreased from 1.56 µgL-1 to 0.028 µgL-1, and after WST values were low (0.059 µgL-1). Dominance of cianobacterias, such as Planktotrhix agardhii (dry season) and Microcystis sp (wet season) was registered in all three areas. In the reservoir and Canal do Pataxó, density of cianobacterias, such as P. agardhii and Microcistys sp., was superior to the values allowed by the Health ministry (HM). However, after WST, density values of cianobacteria were inferior to values established by the HM

Avaliação preliminar da contaminação por BTEX, em água subterrânea de poços tubulares, no município de Natal-RN

Among the different types of pollutants typically attributed to human activities, the petroleum products are one of the most important because of its toxic potential. This toxicity is attributed to the presence of substances such as benzene and its derivatives are very toxic to the central nervous system of man, with chronic toxicity, even in small concentrations. The area chosen for study was the city of Natal, capital of Rio Grande do Norte, where samples were collected in six different areas in the city, comprising 10 wells located in the urban area, being carried out in three distinct periods March/2009, December / June/2010 and 2009, and were evaluated for contamination by volatile hydrocarbons (BTEX - benzene, toluene, ethylbenzene and xylenes), so this work aimed to assess the quality of groundwater wells that supply funding for public supply and trade in the urban area of the city of Natal, in Rio Grande do Norte, contributing to the environmental assessment of the municipality. The analysis of BTEX in water was performed according to EPA Method 8021b. Was used the technique of headspace (TriPlus TP100) coupled to high resolution gas chromatography with selective photoionization detector (PID) and flame ionization (FID) - model Trace GC Ultra, Thermo Electron Corporation brand. The procedure adopted allowed the detection of concentrations of the order of μg.L-1. Data analysis with respect to BTEX in groundwater in the area monitored so far, shows that water quality is still preserved, because it exceeds the limits imposed by the potability Resolution CONAMA Nº. 396, April 2008

Investigação e gerenciamento de áreas contaminadas por postos revendedores de combustíveis em Natal

Activities that have fuel subterranean storage system are considered potentially polluting fuels by CONAMA Resolution 273, due to the possibility of leak, outpouring and overflow of fuel into the ground. Being even more worrying when contaminate groundwater for public supply, as the case of Natal City. For this reason, the Public Ministry/RN, in partnership with UFRN, developed the project environmental suitability of Gas stations in Natal, of which 36% showed evidence of contamination. This paper describes the four stages of the management of contaminated areas: preliminary assessment of environmental liabilities, detailed confirmatory investigation of the contamination, risk analysis to human health (RBCA), as well as the remediation plan of degraded areas. Therefore it is presented a case study. For the area investigated has been proposed a mathematical method to estimate the volume of LNAPL by a free CAD software (ScketchUp) and compare it with the partition method for grid area. Were also performed 3D graphics designs of feathers contamination. Research results showed that passive benzene contamination in groundwater was 2791.77 μg/L, when the maximum allowed by CONAMA Resolution 420 is 5 μg/L which is the potability standards. The individual and cumulative risks were calculated from 4.4 x10-3, both above the limits of 1.0 x10-5 or by RBCA 1.0 x10-6 by the Public Ministry/RN. Corrective action points that remediation of dissolved phase benzene is expected to reach a concentration of 25 μg/L, based on carcinogenic risk for ingestion of groundwater by residents residential, diverging legislation. According to the proposed model, the volume of LNAPL using the ScketchUp was 17.59 m3, while by the grid partitioning method was 14.02 m3. Because of the low recovery, the expected removal of LNAPL is 11 years, if the multiphase extraction system installed in the enterprise is not optimized

Ecologia do fitoplâncton impactado por cultivo de tilápia do Nilo, oreochromis niloticus, em tanques-rede no açude Ministro João Alves, Parelhas, Rio Grande do Norte

The dams are limnic ecosystems of great importance for its multiple uses, among them, water supply for the public and to culture of artisanal fish are most relevant. The aim of the present study is to evaluate the physical-chemical characteristics and the phytoplankton community in two chosen sites (Point 1 littoral zone of point source; Point 2 pelagic zone of non-point source) of the Minister João Alves dam, which is also known as Boqueirão de Parelhas/RN. This represents the spatial distribution of the phytoplankton species in order to understand any possible alterations of the water quality and the phytoplankton composition in relation to the water quality originating from the impact of the tilapia, Oreochromis niloticus, culture. The study period also encompasses temporal variations exhibited in two seasons of an annual cycle, one during the dry season (Oct, Nov and Dec of 2008 and Jan of 2009), and the other rainy season (Mar, Apr, May and June of 2008) to extend the observation. The physicalchemical parameters, such as pH, temperature, electrical conductivity, concentration of dissolved oxygen were measured in situ and the values of the inorganic nutrients (nitrate, ammonium and orto-phosfato) and chlorophyll in the laboratory. The quali-quantitative analyses of the phytoplankton had been carried through sedimentation technique and the enumeration of the random of 400 cells, colonies and filaments counted using Sedgwick-Rafter counting chamber. The results of pH varied widely from the acidic to alkaline range with the minimum of 5.8 (± 0.8) and the maximum of 9.2 (± 0.7-0.8), at point 1 and 2. The dissolved oxygen content was higher in the rainy period than that in the dry period. The maximum electrical conductivity was of 1409 μScm-1 in point 1 and 431 minim of μScm-1, in point 2. There was a considerable alteration in the levels of inorganic nutrients such as nitrate-nitrogen, ammoniacal nitrogen and orthophosphate during the two cycles of study period. Phytoplankton assemblages presented a picture of alternate dominance among species Cyanobacteria, Bacillariophyceae and Chlorophyceae. The trophic state index diagnosed to the category of mesotrophic, which is based on the values of chlorophyll, total phosphorus and Secchi-disc measurements. The wind driven turbulence of the water column and the fresh inflow of water (flushing and dilution) during rainy season acted as constraint and did-not allow an exaggerated growth of the species of cyanobacteria. On the basis of the present we conclude that the culture of tilapias in cage-culture fails to produce pollution load that could compromise the quality of the water of the dam, probably be due to small dimension of the culture in relation to the size, volume of the water and the reservoir capacity support its own environment

A influência da poluição difusa e do regime hidrológico peculiar do semiárido na qualidade da água de um reservatório tropical

In semiarid region of northeast Brazil, the majority of reservoirs used for public supply has suffered degradation of water quality affected by diffuse pollution from agricultural and livestock areas of the watershed and by hydrologic regime peculiar to the region, characterized by a rainy season with higher volumes stored in reservoirs and a dry season with a reduction in water level due to high evaporation and increase of eutrophication. The Dourado reservoir, located in Currais Novos city, semiarid region of Rio Grande do Norte state, is one example of a water supply reservoir that can have degradation of water quality and impracticability of their use, due to the high external input of nutrients from non-point sources of watershed during the rainy season and increasing of eutrophication due to decrease the stored volume during the dry period. This study aimed to investigate and quantify diffuse pollution and the hydrologic regime of semiarid region in order to establish standards regarding the water quality of Dourado reservoir. The study period was between the months of May 2011 to March 2012. The diffuse pollution was quantified in terms of watershed from the mass balance of phosphorus in the reservoir, as in relation to areas under different types of land use within the riparian zone of the reservoir from the assessment of soil chemical properties and losses of phosphorus in each area. The influence of hydrological regime on water quality of the reservoir was evaluated from the monthly monitoring of the morphometric, meteorological and limnological features throughout the study period. The results showed that the reservoir has received a high load of phosphorus coming from the drainage basin and presents itself as a system able to retain some of that load tributary, giving an upward trend of the eutrophication process. Diffuse pollution by nutrients from areas under different types of land use within the riparian zone of the reservoir was higher in areas under the influence of livestock, being this area considered a potential diffuse source of nutrients to the reservoir. Regarding the water regime during the rainy season the reservoir was characterized by high concentrations of nutrients and small algal biomass, while in the dry season the reduction of volume and increase of the water retention time of the reservoir, contributing to the excessive growth algal biomass, favoring an increase in eutrophication and deterioration of water quality. In synthesis the water quality of Dourado reservoir is directed by diffuse pollution coming from the drainage basin and the hydrological regime of the peculiar semiarid region, where the rainy season is characterized by high input of allochthonous compounds from the tributaries and erosion of the soil in the reservoir riparian zone, and the dry season characterized by reducing the storage volume due to high evaporation, high residence time of water and consequent degradation of water quality due to the increase of eutrophication process

Simulação numérica do fluxo hídrico subterrâneo na bacia hidrográfica do Rio Pitimbu RN

Urban centers in Pitimbu Watershed use significant groundwater sources for public supply. Therefore, studies in Dunas Barreiras aquifer are relevant to expand knowledge about it and help manage water resources in the region. An essential tool for this management is the numerical modeling of groundwater flow. In this work, we developed a groundwater flow model for Pitimbu Watershed, using the Visual Modflow, version 2.7.1., which uses finite difference method for solving the govern equation of the dynamics of groundwater flow. We carried out the numerical simulation of steady-state model for the entire region of the basin. The model was built in the geographical, geomorphological and hydrogeological study of the area, which defined the boundary conditions and the parameters required for the numerical calculation. Owing to unavailability of current data based on monitoring of the aquifer it was not possible to calibrate the model. However, the simulation results showed that the overall water balance approached zero, therefore satisfying the equation for the three-dimensional behavior of the head water in steady state. Variations in aquifer recharge data were made to verify the impact of this contribution on the water balance of the system, especially in the scenario in which recharge due to drains and sinks was removed. According to the results generated by Visual Modflow occurred significantly hydraulic head lowering, ranging from 16,4 to 82 feet of drawdown. With the results obtained, it can be said that modeling is performed as a valid tool for the management of water resources in Pitimbu River Basin, and to support new studies

Comportamento sócio-espacial de pessoas em movimento :um estudo exploratório no calçadão da Avenida Engenheiro Roberto Freire

People-environment interaction, focus of Environmental Psychology studies, presupposes that space influences behavior and vice-versa. Despite of the importance of dynamic reciprocity, there are a few works that treat the mobility condition of the people experimenting space. The present study investigates environmental perception of users of the Engenheiro Roberto Freire Avenue sidewalk, one of the few places in Natal for physical activities practicing, where most people are in intense and continuous movement. A few questions for this study where made: In what way does the individual realize the environment while he is moving? How do reciprocal man-environment relations occur there, according to a mobility context? What are the main difficulties and easiness in man-environment interaction under this condition? The search for these answers is based on concepts of social-spatial human behavior - especially personal space, territoriality, density and crowding and contributions of Barker´s Ecologycal Psychology. Considering that the physical space in this case is multifaceted and the perception of theses scenarios is governed by multiples senses and stimuli, it was defined a multi-methodological route: (i) observation participative in loco; (ii) identification of the main behavior settings at the area; (iii) categorization of the activities occurring at the place; (iv) application of a semi-structured interview; (v) images registered and (vi) construction of the researcher s log. The perception of oneself and others in movement in the environment, immersed in a intricate web of inter-actions, makes people develop mobility strategies, many times unconsciously, with the aim of ensuring satisfaction in its activities. Since the Eng. Roberto Freire Avenue sidewalk is an equipment public-urban largely used by the population of Natal, the reflection of the mobility effectiveness in the users environmental perception is expected, providing suggestions for future studies in this field of knowledge

Avaliação da floco-decantação de manta de lodo associada à decantação de alta taxa no tratamento de águas de consumo humano

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Impactos sócio-econômicos e ambientais da introdução da Tilápia do Nilo, Oreochromis niloticus, em açudes públicos do semi-árido nordestino, Brasi

The stocking of exotic fish, especially the tilapia, has become a common practice in the public reservoirs of the Brazilian semi-arid region. The stocking of tilapias has had as its main aim the improvement of the fisheries in the reservoirs and consequently the improvement of the socio-economic conditions of the families that have fishing as the main source of income. However, the environmental risks associated with this practice are high and can lead to a loss in aquatic biodiversity and to changes in the quality of the water. The object of this work was to quantify the socio-economic and environmental effects of the introduction of the Nile tilapia in the public reservoirs of the semi-arid northeastern Brazil. The analysis of the fish yield of 100 public reservoirs from 1970 to 2000 demonstrated that the introduction of the Nile tilapia apparently contributed to an increase in the total fish yield from the late 1970 s until the mid-1980 s. Nevertheless, from that time onwards the fish yield in these reservoirs has fallen into decline to levels inferior to those observed prior to the introduction of the tilápia. The analysis of the fishing activity statistics of the Gargalheiras reservoir located in the city of Acari, Rio Grande do Norte, demonstrated that the introduction of the Nile tilapia in the reservoir has not significantly increased the fish yield, the gross overall income, the gross per capita income nor the number of fishermen actively fishing in the reservoir. On the other hand, the analysis of the fishing activity statistics of the Gargalheiras reservoir has revealed a significant reduction in the captures of other commercially important fish species after the introduction of the tilapia. This result suggests that the Nile tilapia could have negatively affected other species of fish in the reservoir, contributing to the decline in their stocks. In order to assess the perception of the fishermen concerning the effects of the Nile tilapia over other species of fish and the quality of the water, questionnaires containing open and multiple choice questions were applied with 30 fishermen from the colony of the Gargalheiras reservoir. The great majority of the local fishermen stated that the tilapia is currently the most important species of fish to those who depend on fishing as a source of income and that they have not caused damage to other species of fish nor to the quality of the water in the reservoir. However, the results of the present work indicate that the alleged socio-economic benefits, employed to justify the introduction of the Nile tilapia in the reservoirs, are overestimated while the environmental impacts of the introduction of this exotic species are underestimated

Sustentabilidade ambiental do cultivo intensivo de Tilápias (Oreochromis niloticus) em tanques-rede e a capacidade de suporte de quatro reservatórios em uma região semi-árida tropical

Intensive production of tilápias, in cages or net tanks, has been proposed as an alternative to increase fish production, that would generate income and offer animal protein in different tropical and subtropical countries. However, this system of production enriches the aquatic environment with nutrients, principally nitrogen and phosphor derived from the dejections of the metabolism of food and eventual food surpluses consumed by the fishes; the alimentation of the fishes in this production modality is dependent on fish food. The emission of these nutritions in levels above the limit that the system is capable metabolize can provoke a phenomenon called eutrofization, putting in risk the quality of water for public and for fish production activities. In this context the work had as a goal to evaluate the trófico state of the four reservoirs for intensive production of tilapias in net-tanks, in other words, he maximum fish production that the reservoirs are able to hold, keeping the desired quantity of nutrient concentrations in water for public use. The results of the four ecosystems in the Boqueirão de Parelhas reservoir showed that it s possible to have an intensive production of tilapias in net tanks, in this environment the annual average concentration of phosphor, was below the considered critical limits to deflagrate the process of eutrofization in semi-arid regions. The carrying capacity of the Boqueirão de Parelhas reservoir depends on the conversion of the feeding facts and phosphor content in the food but it should vary between 100 and 300 tons per year over a variation in the conversion feeding factor of 1,7 to 2,0:1 and a variation in the P in the food of 0,7 to 0,9%

Ultrasound efficiency in relation to sodium hypochlorite and filtration adsorption in microbial elimination in a water treatment plant

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Prevalência de cárie dentária em escolares de 7 a 12 anos de idade, na cidade de Araraquara, SP (Brasil), 1979

São apresentados os resultados de levantamento epidemiológico de cárie dentária em escolares de 7 a 12 anos de idade da cidade de Araraquara, SP, Brasil, cuja água de abastecimento público é fluoretada. O objetivo do estudo é verificar a prevalência de caria dentária e o nível de assistência odontológica oferecido a esta população. A população de estudo compõe-se de escolares nascidos e sempre residentes na cidade e escolares não nascidos e/ou nem sempre residentes na cidade; são comparados os índices CPO-D obtidos para os dois grupos.

Relações entre condutividade hidráulica, transmissividade, condutância longitudinal e sólidos totais dissolvidos para o aquífero livre de Caçapava do Sul (RS), Brasil

A água subterrânea é um importante recurso ao abastecimento público, principalmente para comunidades periféricas em grandes cidades ou pequenos municípios, onde a instalação ou prolongamento de sistemas de distribuição são economicamente inviáveis. Estudos voltados à análise da vulnerabilidade de aquíferos são relevantes para subsídio a políticas públicas em saneamento básico e preservação ambiental. Este estudo contou com o cadastro de 23 poços rasos localizados no município de Caçapava do Sul (RS), onde foram realizadas medidas de resistividade elétrica e cargabilidade por meio de geofísica, e medidas diretas de condutividade hidráulica e sólidos totais dissolvidos. A análise estatística dos dados demonstrou diversos graus de correlação entre parâmetros, basicamente condicionados a fatores geológicos como porosidade, permeabilidade e sólidos totais dissolvidos.

Epidemiology of fluorosis and dental caries according to different types of water supplies

O objetivo do presente artigo é investigar a relação fluorose/cáries em escolas, de acordo com o nível de fluoreto no abastecimento público de água. A amostra consistiu em 360 alunos de doze anos de idade, de ambos os sexos, que frequentam as escolas próximas da região em que nasceram. As escolas foram classificadas em três grupos de acordo com a presença de fluoreto no abastecimento de água: 1) fluoretação na Estação de Tratamento de Água (ETA); 2) fluoretação direta em poços; e 3) áreas não fluoretadas (ANF). Os testes deχe de Goodman (significância = 5%) foram utilizados para avaliar a associação entre a origem da água e o grau de fluorose. Os resultados mais predominantes foram presença de cáries em toda a amostra (P<0,05); ausência de fluorose em ambos gêneros, para indivíduos brancos e aqueles vivendo em áreas abastecidas com água fluoretada diretamente de poços e não fluoretadas (P<0,05). Não houve diferença no grau de severidade da fluorose entre as fontes de abastecimento de água (P>0,05). As cáries ainda são uma importante questão nessa população, apesar do estabelecimento de medida preventiva. A observação da fluorose em alunos vivendo em áreas não fluoretadas confirma a presença de outras fontes de fluorose.