ABSTRACT
RESUMO O cerne do presente trabalho consistiu em aplicar ferramentas de análise exploratória multivariada objetivando avaliar o número de estações de monitoramento de qualidade da água e a frequência de amostragem. Para tal, utilizou-se banco de dados disponibilizado pelo Instituto Mineiro de Gestão das Águas (IGAM) referente à Bacia do Rio das Velhas, na região central mais populosa de Minas Gerais. Foram utilizadas as técnicas de análise das componentes principais (ACP) e a rede neural de Kohonen, que culminaram na significativa redução da frequência de amostragem, em alguns casos de mensal para anual ou semestral, e na redução do número de estações de monitoramento de 36 para 33. Os resultados permitem abrir a possibilidade do emprego dos métodos utilizados como ferramentas de gestão de recursos hídricos de bacias hidrográficas visando à otimização dos programas de monitoramento de qualidade de água.
ABSTRACT The core of this work consisted of applying multivariate exploratory analysis tools to evaluate the number of water quality monitoring stations and the sampling frequency. In such way, the database provided by the Minas Gerais Institute of Water Management (IGAM) on the river basin of Rio das Velhas, in the most populous central region of Minas Gerais state, was used. The Principal Components Analysis and the Kohonen neural network techniques were applied, resulting in a significant reduction in sampling frequency, in some cases from monthly to annual or semi-annual, and in the reduction of the number of monitoring stations from 36 to 33. The results open the possibility of using these methods as watershed water resources management tools aimed at optimization of water quality monitoring programs.
ABSTRACT
RESUMO Neste estudo foram avaliados os efeitos do tamanho da partícula e de variações da concentração de sedimentos suspensos (CSS) sobre as leituras de turbidez de três sensores óptico-nefelométricos, com iguais características ópticas e geométricas, utilizando amostras de sedimentos suspensos coletadas na seção fluviométrica da bacia do Turcato (19,5 km²), localizada na Região Sul do Brasil. O material coletado passou por processos de peneiramento e pipetagem para fracionamento nas granulometrias areia e silte. Para cada diâmetro foram separadas frações com diferentes concentrações de sedimentos, variando entre 0,01 e 5,00 g.L-1. Os resultados demonstram grande influência da CSS e do tamanho da partícula sobre a turbidez. Para qualquer situação, o aumento da turbidez é inverso ao tamanho da partícula e diretamente relacionado ao aumento da CSS. As variações da turbidez, expressas em função da CSS (sensibilidade do sensor), são maiores para menores diâmetros, atingindo valores quase constantes para partículas de areia. As leituras de turbidez dos três sensores não apresentaram diferença significativa no nível de 5% pelo teste de Mann-Whitney rank sum . Para uma mesma CSS, a leitura de turbidez pode ser diferente, conforme a classe granulométrica analisada. A turbidez registrada pelo sensor para a classe silte equivale a uma turbidez observada para uma CSS dez vezes menor para a classe das areias.
ABSTRACT This study evaluates the effects of particle size and variations of CSS on turbidity readings of three optical-nephelometric sensors using sediment samples collected in the field. Samples were collected in fluviometric station at Turcato basin (19.5 km²), located in the South region of Brazil. The collected material underwent screening and pipetting processes for fractionation in sand and silt grain size. For each diameter were separated fractions with different sediment concentration ranging between 0.01 and 5.00 g.L-1. The results demonstrate great influence of CSS and particle size on turbidity readings. The increase in turbidity is opposite to particle size and directly related to CSS. Variations in turbidity, expressed in CSS function (sensor sensitivity), are higher for smaller diameters, reaching almost constant values for sand particles. Turbidity readings of the three sensors showed no significant difference in the level of 5% by the Mann-Whitney rank sum test. For a given CSS, the turbidity reading may be different, depending on the granulometric class analyzed. Turbidity recorded by the sensor to the silt-class is equivalent to a sensor response observed for a CSS ten times lower for the sand class.
ABSTRACT
Questions have been raised about the quality of roof harvested rainwater which has been shown to be temporally and spatially variable and at times not in compliance with drinking water guidelines. This study is therefore an investigation on the quality of roof harvested rainwater consumed by rural communities in parts of Anambra State Nigeria. The physicochemical and microbiological parameters of the rainwater samples collected in the study area were analyzed with the view of determining the level of contamination as a result of anthropogenic activities in the study area. Roof harvested rainwater were collected from three stations, and a free-fall harvested rainwater sample was used as a control. The result shows that the physico-chemical parameters were all within permissible water quality standard as recommended by National Agency for Food and Drug Administration Control (NAFDAC) except for the presence of particles and for the micro-biological properties which were found quite unsatisfactory. Pearson Correlation Matrix of physicochemical properties conducted indicated a strong positive correlation between Zinc and Iron which emphasizes common pathway and origin. The water samples were assessed using Water Quality Index (WQI), the WQI for the station 1, 2 and 3 were 71.68%, 60.19%, and 77.55% respectively. Low-cost microbial disinfection such as solar disinfection and pre-filtration or otherwise the proper maintenance of the entire Rain Water Harvesting (RWH) system could make the harvested roof rainwater potable for the study area.
ABSTRACT
Este artigo apresenta as fases de uma pesquisa-ação empreendida para avaliar e aprimorar as práticas do Programa de Vigilância em Saúde Ambiental relacionada à qualidade da água para consumo humano (Vigiagua) em três municípios do estado de Minas Gerais, Brasil. Com o emprego do método qualitativo, objetivou-se detalhar os processos desencadeados durante as fases da pesquisa, problematizando-os metodologicamente e discutindo os desafios e potencialidades decorrentes da operacionalização do método. Constatou-se que a pesquisa-ação possibilitou a apropriação e o envolvimento dos sujeitos implicados na pesquisa; a criação de espaços intersetoriais, inter e intrainstitucionais; o estabelecimento de novas relações e a ampliação do conhecimento acerca do objeto trabalhado. Esses ganhos, possivelmente, transcenderão à própria pesquisa realizada.
This work presents the stages of an action research applied to assess and improve the practices of the Environmental Monitoring Program related to water quality for human consumption (Vigiagua) in three municipalities of Minas Gerais, Brazil. It aimed to detail the processes triggered during each phase of the action research, exploring methodological challenges and opportunities arisen, using a qualitative method. It was verified that the use of the action research allowed empowerment of actors involved in the research; the establishment of inter and intra-institutional and intersectoral spaces and new relationships and the expansion of the knowledge about the subject in question. These achievements will possibly transcend the research itself.
ABSTRACT
Objective To know the situation of the water environment in the Eling Lake Area and provide the theoretical basis for protecting the biosystem of this area. Methods The water samples were collected from the sites 0.5 meters below the water surface of input and output water area, the water area near the east and west bank of the Eling Lake, the center of the lake, and also from the sites 0.5 meters above the bottom of the lake .The water sampling was carried out in August 2005, October 2005 and May 2006. Country standard method was used to determine the physical and chemical characteristics of water samples. The sampling, determination and evaluation in the investigation were according to related standard regulations. Results The water temperature was 5.6 ℃, pH value was 8.49, the total amount of Ca2+ and Mg2+, suspended matter, chlorides, sulfate, DO, COD, BOD5, Cu2+ and Zn2+ were 95.4 mg/L, 87.0 mg/L, 45.0 mg/L, 80.0 mg/L, 7.1mg/L, 11.0 mg/L, 2.0 mg/L, 0.002 mg/L and 0.009 mg/L respectively. Conclusion All of the physical and chemical characteristics of the water samples meet the water quality criterion of the class ruled by GB 3838-2002, and the water can be used as source water.
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Objective To know the present sanitary status of bathing beach in Haikou,and provide the scientific data for improving the assessment of microorganisms contamination of bathing beach. Methods The routine water quality data and related meteorological data of the bathing beach were collected from 2007 to 2009. In July 8th-10th 2009,a high grade bathing beach and an ordinary one were selected,four sampling sites were selected where the contamination by feces were often seen,the number of swimmers was the largest,the samples were collected from the deep-water areas and sand beach respectively,and fecal coliform and enterococcus were examined. Results The concentration of fecal coliform was(1 085.8?538.8)cfu/L in water and(120 000.0?32 659.9)cfu/1 000 g in sand,and the E.faecalis was(32.5?19.1)cfu/L in water and(2 425.0?689.8)cfu/1 000 g in sand. The numbers of the two kinds of bacteria in water decreased with the increase of distance from the land. The concentration of bacteria was positively correlated to the day's rainfall(P