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1.
Acta odontol. latinoam ; 36(3): 169-176, Dec. 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1533523

RESUMO

ABSTRACT Fluorosis is a worldwide public health problem. One of the factors related to it is the type of water consumed, such as groundwater. High fluoride concentration in groundwater may be explained by contamination from local industries. Since fluoride and arsenic are the main pollutants of groundwater, some studies correlate groundwater consumption with high prevalence of fluorosis Aim The aim of this study was to conduct a systematic review to determine whether children's risk of fluorosis is related to drinking groundwater Materials and Method The protocol for this systematic review was registered at the National Institute of Health Research Database (CRD42021227298). A comprehensive search was conducted to identify potentially relevant studies by exploring a range of electronic databases (Medline via PubMed, Scopus, Cochrane Library, Science Direct, Web of Science Core Collection, Medline via Ovid, Lilacs, Embase, and grey literature) Results A total 2189 articles were found. After reading titles and abstracts, 63 were selected for screening, and the final data was extracted from 15 articles Conclusion A relationship was identified between drinking fluoridated water from wells and the prevalence of fluorosis in individuals up to 18 years old. This is the first study to assess the issue systematically worldwide.


RESUMEN La fluorosis es un problema de salud pública a nivel mundial y el tipo de agua consumida es uno de los factores relacionados con ella, como el consumo de aguas subterráneas. La alta concentración de fluoruro en estas aguas puede justificarse por la contaminación por industrias locales y las características del suelo, donde algunos estudios correlacionan el consumo de aguas subterráneas con una alta prevalencia de fluorosis, ya que el fluoruro, junto con el arsénico, se consideran los principales contaminantes de estas aguas Objetivo El objetivo es realizar una revisión sistemática que relacione el riesgo de fluorosis en niños expuestos al consumo de agua procedente de pozos Materiales y Método El protocolo de esta revisión sistemática fue registrado en el National Institute of Health Research Database (CRD42021227298). Se realizó una búsqueda bibliográfica de estudios primarios explorando diversas bases de datos electrónicas (Medline vía PubMed, Scopus, Cochrane Library, Science Direct, Web of Science Core Collection, Medline vía Ovid, Lilacs, Embase y literatura gris) Resultados Se encontraron 2189 artículos, tras la lectura de títulos y resúmenes se seleccionaron 63 referencias para examinar y, finalmente, se extrajeron los datos de 15 artículos Conclusiones Se identificó una relación entre el consumo de agua fluorada de pozo y la prevalencia de fluorosis en individuos de hasta 18 años, siendo este estudio el primero en evaluarlo sistemáticamente a nivel mundial.

2.
Artigo | IMSEAR | ID: sea-218841

RESUMO

The shortage and contamination of sources of surface water, as well as the increasing demand for agricultural practices, groundwater is important for many domestic, commercial, and industrial purposes. Human health and agricultural yields were significantly affected either by quality and concentration levels of groundwater. 25 groundwater samples were used in this study, which has been conducted in five different mandals of the Palnadu region. The samples were obtained from a variety of bore wells using the random sampling method, and the physical and chemical characteristics of water quality parameters were evaluated. The study covered the maximum amount of groundwater in the five mandals of Nuzendla, Vinukonda, Savalyapuram, Romicharla and Ipur as well as the suitable treatment methods for trying to turn the water in to the potable form.

3.
Artigo | IMSEAR | ID: sea-216830

RESUMO

Objectives: This study investigates the estimation of the fluoride concentration in drinking water in Rohtak district, Haryana, and quantifies its effect on the prevalence of dental fluorosis and dental caries. Materials and Methods: A cross-sectional survey was conducted among 1262 school children in endemic fluoride areas of Haryana. Using simple random sampling, thirty villages from five blocks of Rohtak districts were selected, and children 6–12 years of age were examined. A questionnaire survey form was filled out to record the demographic details of the samples. Dental caries was recorded according to DMFT (D = Decayed, M = Missing due to caries only, F = Filled, T = Teeth)/deft index (d = decayed, e = extracted due to caries, f = filled, t = teeth). Assessment of Dental Fluorosis was done according to Dean's Fluorosis index, modified in 1942. The data were analyzed using SPSS version 19, and nonparametric tests were used to assess the significance. Results: The study participants included 615 males and 647 females among which Mean DMFT in the area of study ranged from 0.32 to 1.90. Mean deft in the area of study ranged from 0.34 to 1.91. The fluoride concentrations in groundwater are in the range of 0.532–8.802. Out of 1262 children examined, 655 (51.90%) children were having dental fluorosis. 607 (48.10%) of the subjects were free from fluorosis. 16.09%, 13.39%, 9.11%, and 8.16% and 5.15% were having questionable, very mild, mild, moderate, and severe form of fluorosis, respectively. Conclusion: It can be concluded that in Rohtak district, the fluoride levels in drinking water and the prevalence of dental fluorosis are high, so requiring an urgent need to improve the quality of water and institute de-fluoridation of drinking water in affected areas to lower the burden of dental fluorosis in the community.

4.
Eng. sanit. ambient ; 26(6): 1085-1095, nov.-dez. 2021. tab, graf
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1350708

RESUMO

RESUMO Fases líquidas não aquosas leves (LNAPL), como combustíveis líquidos, estão presentes em muitas áreas contaminadas. Para o gerenciamento dessas áreas, é importante conhecer a mobilidade desse produto, a fim de subsidiar decisões sobre sistemas de remediação e avaliação de risco. Uma alternativa para quantificar a mobilidade é o parâmetro transmissividade de LNAPL, ainda pouco aplicado no Brasil. Esse trabalho avaliou a aplicabilidade desse parâmetro em diferentes áreas contaminadas por LNAPL. Foram realizados testes em três áreas com litologias, tipos de contaminantes e históricos de contaminação distintos. Em alguns testes, não foi possível determinar a transmissividade de LNAPL devido à instabilidade do nível de fluidos, por consequência da operação de sistemas de bombeamento e precipitação, além de problemas operacionais durante a realização do teste. Apesar de ser um teste simples, em alguns casos, a determinação de transmissividade de LNAPL pode ser inviável, principalmente para LNAPL de baixa mobilidade por requerer testes mais prolongados. Os principais fatores determinantes no valor de transmissividade de LNAPL foram a litologia, a posição do poço na pluma e a posição do nível d'água em relação a série histórica. Assim, a transmissividade de LNAPL pode ser um parâmetro útil no gerenciamento de áreas contaminadas, cuja interpretação deve ser feita de forma cautelosa e integrada com outros dados de investigação da área.


ABSTRACT Light non-aqueous phase liquids (LNAPL), such as liquid fuels, are present in many contaminated sites. To adequately manage these sites, it is important to know the product mobility, to support decisions on remediation systems and risk assessment. One alternative to quantify mobility is to quantify the LNAPL transmissivity, which is rarely applied in Brazil. This work aimed to evaluate the applicability of this parameter in LNAPL contaminated sites with different conditions. Tests were performed in three sites, with different lithologies, types of contaminants and contamination histories. In some tests, it was not possible to obtain representative values of LNAPL transmissivity due to fluids levels instability, caused by pumping systems and precipitation events, and operational problems during the tests. Despite being a simple test, in some cases, the determination of LNAPL transmissivity may not be feasible, especially for low mobility LNAPLs, that require long period tests. The main factors controlling LNAPL transmissivity values were lithology, position of the well in the plume, and water level elevation in relation to the historical series. Thus, LNAPL transmissivity can be a useful parameter in the management of contaminated sites, but its interpretation must be made cautiously and integrated with other site data.

5.
Eng. sanit. ambient ; 26(3): 401-407, maio-jun. 2021. tab
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1286319

RESUMO

RESUMO A crescente demanda e a diminuição da disponibilidade de água com qualidade devido à degradação constituem um desafio para os gestores dos recursos hídricos. As águas subterrâneas são recursos hídricos importantes que, em geral, apresentam boa qualidade. Porém, a elevação da contaminação das águas subterrâneas, causada principalmente por atividades antropogênicas e uso do solo, coloca em risco a segurança hídrica. A avaliação dos recursos hídricos subterrâneos e as decisões tomadas para proteção contra a degradação fazem parte de um processo complexo. A avaliação de áreas vulneráveis ao risco de contaminação é uma análise essencial para o planejamento e gestão. Neste estudo, utilizou-se metodologia multicritério para proposição de um modelo de avaliação da vulnerabilidade ao risco de contaminação por meio de informações de poços que fornecem água para o abastecimento público, destacando-se as áreas mais impactadas pela ação antropogênica. Doze poços foram avaliados quanto aos critérios: índice GOD, nitrato, potencial hidrogeniônico, sólidos totais dissolvidos e coliformes totais. A aplicação do método de multicritério AHP e TOPSIS resultou na ordenação dos poços que estão mais vulneráveis e que necessitam de medidas de proteção e controle de degradação. Os poços que são considerados mais vulneráveis estão localizados em meio urbano; assim, pode-se inferir que estão sendo degradados por efluentes lançados no solo sem o devido tratamento.


ABSTRACT The growing demand and the declining availability of quality water due to degradation are a challenge for water resource managers. Groundwater is a vital water resource that is generally of good quality. However, with the increase of contamination caused mainly by anthropogenic activities, water safety is put at risk. The assessment in groundwater resources and decision-making to protect against degradation is a complex process. Assessing areas vulnerable to contamination risk is an essential analysis for planning and management. In this study, we used the multi-criteria methodology to propose a model for assessing vulnerability to contamination risk through information from wells that provide water for public supply, highlighting the areas most impacted by anthropogenic action. Twelve wells were evaluated under the following criteria: GOD index, nitrate, hydrogen potential, total dissolved solids, and total coliforms. The application of the AHP and TOPSIS multi-criteria methods resulted in the ordering of the wells that are most vulnerable and that need protection and degradation control measures. The wells that are considered more vulnerable are located in urban areas, so it can be inferred that they are being degraded by activities by effluents released into the soil without proper treatment.

6.
Eng. sanit. ambient ; 26(2): 273-281, Mar.-Apr. 2021. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1249764

RESUMO

ABSTRACT This research aimed to investigate the relation between sanitary situation and groundwater quality, using the concentration of nitrogenous compounds. The aquifer studied is unconfined and situated in the periurban zone of Fortaleza (NE Brazil). Through the Geographic Information System (GIS), a relational database was created using data from the IBGE demographic census (2011), to analyze numbers of households linked to septic tanks or rudimentary cesspit. The groundwater quality was evaluated based on nitrogen compounds (N-NH3 +; NO2 -; N-NO3 -), pH, and total dissolved solids (TDS). The highest concentrations of nitrates are found in areas with a higher density of septic tanks and rudimentary cesspit. Furthermore, nitrate was more present in water table above 6.6 m, mainly in the interfluvial zones, which have a high oxidation potential. The results contribute to the loss of contamination, based on the number of households with septic tanks and rudimentary cesspit, in unconfined aquifers, which were more vulnerable to contamination, mainly in peripheric expansions areas in the cities, where the deficit in sewage services tends to be high.


RESUMO Esta pesquisa teve como objetivo investigar a relação entre a situação sanitária e a qualidade da água subterrânea, usando concentrações de compostos nitrogenados. O aquífero estudado é do tipo livre e se encontra situado na zona periurbana da cidade de Fortaleza (NE Brasil). Através do Sistema de Informação Geográfica (SIG), foi criado um banco de geodados relacional utilizando dados do censo demográfico do IBGE (2011), analisando o número de domicílios vinculados a fossas sépticas e fossas rudimentares. A qualidade da água subterrânea foi avaliada com base em compostos nitrogenados (N-NH3 +; NO2 -; N-NO3 -), pH e sólidos totais dissolvidos (STD). As altas concentrações de nitrato estão associadas a maior ocorrência de fossas sépticas e rudimentares, principalmente. Além disso, a ocorrência do nitrato ocorre em áreas de níveis estáticos acima de 6,6 m, principalmente nos setores interfluviais, que apresenta alto potencial de oxidação. Os resultados contribuem para predição da contaminação, tendo em vista a quantidade de domicílios com fossas sépticas e rudimentares, sobre aquíferos livres, que são mais vulneráveis à contaminação, sobretudo em áreas de expansão periférica da cidade, onde o déficit de esgotamento sanitário tende a ser maior.

7.
Kasmera ; 49(1): e49132183, ene-jun. 2021.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1352447

RESUMO

En zonas insulares, la principal fuente de agua para el consumo proviene de pozos o acuíferos, por lo cual es importante conocer su distribución y calidad. El presente estudio tuvo como objetivo caracterizar el recurso hídrico subterráneo, a través de los pozos ubicados en la isla San Bernardo, como un aporte al desarrollo de la comunidad y la prevención de enfermedades de transmisión hídrica. Se determinó la ubicación y materiales de construcción de los pozos de agua y pozos sépticos, a fin de determinar el área de cobertura y distribución de estos. Se detectaron 15 pozos de agua construidos con diferentes materiales y diferentes profundidades. Se cuantificaron los coliformes totales, coliformes fecales, E. coli, enterococos y Pseudomonas. Igualmente, se midió el pH, salinidad, turbidez, sólidos disueltos totales y conductividad eléctrica. Todas las muestras de agua mostraron condiciones fisicoquímicas variables y contaminación microbiológica, lo cual la hace inapropiada para el consumo. Se determinó una distribución amplia del recurso y la necesidad de desinfección del agua. Se recomienda la organización de los pozos de agua a fin de lograr una distribución adecuada, el tratamiento del agua extraída de los mismos y la evaluación de la posible reubicación de los pozos sépticos


In insular areas, the main sources of water for consumption are wells or aquifers, so it is important to know its distribution and quality. The objective of this study was to characterize the water resources of the San Bernardo Island as a contribution to the community development and prevention of waterborne diseases. The area of coverage and location of wells and septic tanks, was determined, in order to establish their area of coverage and distribution. Fifteen water wells constructed with different materials and different depths, were detected. Total coliforms, fecal coliforms, E. coli, enterococci and Pseudomonas were quantified. Also, pH, salinity, turbidity, total dissolved solids, and electrical conductivity, were measured. All water samples showed variable physicochemical conditions, and microbiological contamination, making it unsuitable for consumption. The results showed a wide distribution of the resource and the need for water disinfection when used for human consumption. Water well organization to achieve adequate distribution, the treatment of water extracted from the wells, and an evaluation for relocation of septic tanks is strongly recommended

8.
Chinese Journal of Biotechnology ; (12): 3549-3564, 2021.
Artigo em Chinês | WPRIM | ID: wpr-921447

RESUMO

Bioremediation is regarded as one of the most promising methods for the remediation of the soil and groundwater contaminated with organic compounds, mainly due to its cost-effectiveness and environmental friendliness. Using VOSviewer and CiteSpace, we analyzed all publications in this area in core database of Web of Science from 1990 to 2020. The number of publications in this area showed an increasing trend worldwide. The country with the largest total number of publications was USA, followed by China and India. Since 2012, the number of annual publications of China exceeded USA and ranked the first. The top three journals which published papers in this area were Chemosphere, Environmental Science & Technology, and Science of the Total Environment. The Chinese Academy of Sciences published the largest number of papers among the research institutions globally, but the University of California in USA had the highest total citations and h-index. Bibliometric analysis indicated that it is important to develop biotechnologies of bioremediation coupled with chemical/physical remediation to overcome the challenge of low efficiency and long remediation duration associated with bioremediation. In addition, the bioremediation on the mixed contaminants, such as organic contaminants and heavy metals, or mixtures of different organic contaminants, is an important direction. Finally, the rapid development of microbiome technologies will further promote the exploration of mechanisms involved in bioremediation on the genetic and molecular level.


Assuntos
Bibliometria , Biodegradação Ambiental , Água Subterrânea , Publicações , Solo
9.
Braz. arch. biol. technol ; 64: e21200132, 2021. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1153298

RESUMO

HIGHLIGHTS Arsenic is considered as one of the highly hazardous elements in the environment and a serious carcinogen for the human health. An enzymatic method has been described by using arsenite oxidase for arsenic detection. Residual activity of the immobilized enzyme was 43% of the initial activity after being recycled 10 times.


Abstract Arsenic is considered as one of the highly hazardous elements in the environment and a serious carcinogen for the human health. More attention has taken towards the arsenic due to its presence in ground water in India, China, Bangladesh, Inner Mongolia and several other regions of the world. It's been a challenge to remove arsenic due to the lack of its efficient detection approach in the complicated environmental matrix. The proposed method describes an enzymatic method for arsenic determination using arsenite oxidase, which catalyzes the oxidation of arsenite to arsenate. Hence, a colorimetric PVC strip with immobilized arsenite oxidase has been developed to detect the arsenic concentration and also having potential for the field-testing. The influence of the optimal conditions i.e. pH, temperature, storage stability, and reusability of free and immobilized enzyme were evaluated and compared. The results have shown that the stabilities were significantly enhanced compared with free counterpart. Residual activity of the immobilized enzyme was 43% of the initial activity after being recycled 10 times. We approve that this novel low cost immobilized carrier presents a new approach in large scale applications and expected to act as a model for establishment of indigenous arsenic sensor in miniature form.


Assuntos
Humanos , Arsênio/análise , Cloreto de Polivinila/análise , Poluentes Químicos da Água/análise , Água Subterrânea/análise , Enzimas Imobilizadas/análise , Oxirredutases , Biodegradação Ambiental
10.
Int. j. odontostomatol. (Print) ; 14(4): 596-601, dic. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1134545

RESUMO

ABSTRACT: Many areas of South America are directly affected by Arsenic (As) contaminated groundwater. A high percentage of the water samples taken in multiple areas of Argentina had As concentrations above the WHO level recommended guidelines. This condition was previously associated with an increased risk of chronic diseases, including different cancers. Long-term As exposure was proposed as a risk factor for Oral Squamous Cell Carcinoma (OSCC). The aim of this study is to present a series cases of Argentine patients diagnosed with OSCC who have consumed water contaminated with As for more than 10 years. Clinical data were obtained from the archive of Clinical Records Histories of the Oral Medicine Department of the Dentistry School, Universidad Nacional de Córdoba and Universidad Católica de Córdoba, Argentina. 15 cases of OSCC were included. The male: female sex ratio was 2:1. The average age was 66 years (31-89 years). Regarding location, the gum or edentulous alveolar ridge was the most prevalent site (6/15; 40 %), followed by the tongue margin. The average years of exposure to arsenical waters were 24 years (13 - 40 years of exposure). The majority of the presented cases were non drinkers non smokers. 60 % of the tumors were diagnosed at advanced stages. the epidemiological studies carried out in As-contaminated areas that address oral cancer should always incorporate the record of variables related to As exposure. Patients who live or lived at As-contaminated areas must be regularly followed up for early diagnosis of potentially malignant or malignant lesions. The high frequency of gum cancer among these cases, should raise awareness of periodontic specialists to perform a careful and thorough periodontal examination.


RESUMEN: Muchas regiones de América del Sur están directamente afectadas por aguas subterráneas contaminadas con arsénico (As). Un alto porcentaje de las muestras de agua tomadas en múltiples áreas de Argentina tenían concentraciones de As superiores al nivel aprobado por la OMS. Esta condición se asociaba previamente con un mayor riesgo de enfermedades crónicas, incluidos diferentes tipos de cáncer. La exposición a largo plazo se propuso como un factor de riesgo para el carcinoma oral de células escamosas (OSCC). El objetivo de este estudio es presentar una serie de casos de pacientes diagnosticados con OSCC que han consumido agua contaminada con As durante más de 10 años. Se obtuvieron datos clínicos del archivo de Historias de registros clínicos del Departamento de Medicina Oral de la Facultad de Odontología, Universidad Nacional de Córdoba y Universidad Católica de Córdoba, Argentina. Se incluyeron 15 casos de OSCC. La relación de género masculino: femenino fue de 2: 1. La edad promedio fue de 66 años (31-89 años). En cuanto a la ubicación, la encía o la cresta alveolar edéntula fue el sitio más frecuente (6/15; 40 %), seguido del borde de la lengua. El promedio de años de exposición a las aguas arsenicales fue de 24 años (13 - 40 años de exposición). La mayoría de los casos presentados fueron de pacientes no bebedores y no fumadores. El 60 % de los tumores fueron diagnosticados en etapas avanzadas. Los estudios epidemiológicos realizados en áreas contaminadas con As que abordan el cáncer oral siempre deben incorporar el registro de variables relacionadas con la exposición a As. Se debe hacer un seguimiento continuo de los pacientes que viven o que vivieron en áreas contaminadas con As para el diagnóstico temprano de lesiones potencialmente malignas. La alta frecuencia de cáncer de encías en estos casos, debe concienciar a los especialistas en periodoncia para que realicen un examen periodontal cuidadoso y completo.


Assuntos
Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Neoplasias Bucais/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Argentina , Arsênio/efeitos adversos , Neoplasias Bucais/terapia , Prontuários Médicos , Carcinoma de Células Escamosas de Cabeça e Pescoço/terapia
11.
Kasmera ; 48(1): e48131414, ene-jun 2020.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1103166

RESUMO

El crecimiento de la población humana y las actividades antropogénicas ha aumentado la tasa de contaminación del agua subterránea en el mundo, por lo que, la finalidad de este estudio es determinar la potabilidad del agua de cuatro pozos subterráneos de un área rural del estado Mérida, mediante la caracterización fisicoquímica y microbiológica, para comprobar la factibilidad de su uso como agua de consumo. Los resultados indican que los parámetros fisicoquímicos cumplen la normativa venezolana. Las aguas presentan una gran variedad de minerales destacándose Ca, Na y Mg como cationes mayoritarios y una dureza básicamente debía a iones bicarbonato. Los valores de la distribución isotópica, sugieren la existencia de dos acuíferos sin conexiones hidráulicas entre los pozos. El análisis bacteriológico y parasitológico detecta: bacterias heterótrofas, coliformes totales y Pseudomonas, así como, Ascaris spp., Blastocystis sp., Giardia sp., y Eimeria sp., probablemente procedentes del filtrado subterráneo de los pozos sépticos y percolado desde la superficie a través del suelo de textura franco arcilloso arenoso, microorganismos que se han adaptado a las características fisicoquímicas de las aguas. Los resultados demuestran que el agua de tres pozos, no puede ser utilizada para el consumo, sin previo tratamiento convencional como coagulación, filtración y cloración


Growth in human population and anthropogenic activities has increased the rate of groundwater pollution in the world, therefore, the purpose of this study is to determine the potability of water from four underground wells in a rural area of Mérida State, through the physicochemical and microbiological characterization, to check the feasibility of its use as drinking water. The results indicate that the physicochemical parameters comply with venezuelan regulations. The waters have a wide variety of minerals, highlighting Ca, Na and Mg as majority cations and a hardness basically due to bicarbonate ions. The values of the isotopic distribution suggest the existence of two aquifers without hydraulic connections between wells. Bacteriological and parasitological analysis detects: heterotrophic bacteria, total coliforms and Pseudomonas, as well as Ascaris spp., Blastocystis sp., Giardia sp., and Eimeria sp., probably derived from the underground filtration of septic tanks and percolated from the surface through the sandy clay loam soil, microorganisms that have adapted to the physicochemical characteristics of waters. The results show that the water from three wells cannot be used for consumption without some conventional treatment as filtration and coagulation, and disinfection process

12.
J Environ Biol ; 2020 Mar; 41(2): 186-194
Artigo | IMSEAR | ID: sea-214492

RESUMO

Aim: Arsenic concentration in groundwater above the acceptable level is of global concern due to its serious human health effects. Application of certain fungi, due to their amazing skill to remove arsenic from arsenic contaminated water has received attention in recent years. The main aim of this study was to isolate arsenic tolerant fungi from arsenic-contaminated groundwater and assess their ability for arsenic removal from the aquatic system in-vitro.Methodology: Fungi were isolated from arsenic-contaminated groundwater (44.9–161.1 mg l-1). An experiment on bioremediation/ removal of arsenic by selected highly arsenic tolerant fungi was conducted by culturing them in arsenic supplemented medium and measuring the arsenic contents in initial and after incubation with fungi using Hydride Generation Atomic Absorption Spectroscopy (HG-AAS) to find out the arsenic removal percentage. Results: In all, ten out of forty-five fungi obtained from highly arsenic-contaminated groundwater (44.9–161.1 mg l-1) were able to remove high arsenic contents (>80%) from liquid medium with >85% arsenite (by 6 fungal isolates) and >85% of arsenate (by 9 fungal isolates). In arsenic tolerance assay, all 10 test fungi grew readily in liquid medium enriched with either arsenate (10 and 20 g l-1) or arsenite (2 g l-1) under laboratory conditions (27±2°C). These fungi showed log phase between 5 to 10 days with stationary phase of 11-15 days. High arsenite concentration (4 g l-1) however, completely inhibited the growth of 50% of these fungal isolates. Five of these isolates showed high tolerance index pattern (0.97- 0.91) as compared to others (0.22–0.13). These fungi greatly altered the pH of arsenic supplemented liquid medium (10 mg l-1) as compared to the control when they were individually cultured. These arsenic tolerant fungal isolates may effectively be used for the bioremediation of arsenic from groundwater. Interpretation: The study suggested that 10 fungal isolates were able to tolerate high arsenic concentrations (20 g l-1 of arsenate and 2 g l-1 of arsenite) and were able to enhance arsenic removal (more than 80%) in liquid medium at neutral pH (7.0) and 27°C temperature.

13.
J. Health Sci. Inst ; 38(2): 107-116, abr - jun 2020. tab
Artigo em Português | LILACS | ID: biblio-1399873

RESUMO

Objetivo ­ Verificar a concentração de nitrato e a presença ou ausência de bactérias da espécie Escherichia coli em amostras de água subterrânea (poços) destinadas ao consumo humano e comparar os resultados aos Valores Máximos Permitidos (VMP) pela Portaria 2.914 do Ministério da Saúde. Métodos ­ Durante um ano (2017-2018), semestralmente, foram coletadas amostras de águasconsumidas por moradores em diferentes pontos: poços 1 e 2, ambos sem tratamento e com o auxílio de amostradores descartáveis do tipo bailer e; torneiras, denominados S1 e S2, água tratada pela Companhia de Saneamento Básico do Estado de São Paulo (SABESP) e destinadas ao abastecimento público. Esses últimos como grupo controle, pois não foram identificados poços de monitoramento ou nascentes próximas sem contaminação. As amostras em frascos apropriados foram preservadas em caixas térmicas (± 4°C) e encaminhadas para análise química e microbiológica, seguindo os protocolos de coletas da CETESB e USEPA e os métodos 4500-NO3-B e 9215c da APHA. As análises físico-químicas, tais como pH, OD, temperatura, cloro livre, condutividade elétrica e profundidade foram realizadas em campo com equipamentos, tais como multiparâmetro da marca Hanna Hi 9828 e outros. Resultados ­ Verificou-se que as águas subterrâneas são de natureza rasas (poços com profundidade < 20 m) e suas águas ligeiramente ácida (pH=5,0). Em ambos os poços houve a presença de bactérias E. coli e elevada concentração do íon nitrato (>18 mg/L) no período seco e chuvoso, estando em não conformidade ao VMP dado pela Portaria 2.914. As amostras S1 e S2 apresentaram ausência de E.coli e valores abaixo de 0,5 mg/L de N-NO-3. informação dos parâmetros de qualidade nos rótulos. O levantamento de alguns rótulos, mostrou que em cinco marcas de água envasadas, três delas estão não conforme a VMP ora citada (NO-3-N > 10 mg/L). Conclusão ­ O presente estudo demonstrou que para fins de potabilidade a água dos poços está imprópria para o consumo humano


Objective ­ To verify nitrate concentration, the presence or absence of Escherichia coli bacterium in groundwater samples (wells) intended for human consumption, and to compare the results to Maximum Permitted Values (MPV) by Portaria 2.914 of the Ministry of Health. Methods ­ During one year (2017-2018), samples of water consumed by residents at different points were taken every semester: wells 1 and 2, both without treatment and with the aid of disposable samplers of the bailer type; taps, called S1 and S2, water treated by the Basic Sanitation Company of the State of São Paulo (SABESP) and intended for public supply. The latter as a control group because no monitoring wells or nearby springs were identified without contamination. The samples in appropriate flasks were preserved in thermal boxes (± 4°C) and sent for chemical and microbiological analysis, following CETESB and USEPA collection protocols and APHA methods 4500-NO3-B and 9215c. Physical-chemical analyzes, such as pH, OD, temperature, free chlorine, electrical conductivity and depth were performed in the field with equipment such as multi-parameter, Hanna brand and others. Results ­ Groundwaters were found to be shallow (wells with depth <20 m) and their waters slightly acidic (pH = 5.0). In both wells, the presence of E. coli bacteria and high concentration of nitrate ion (> 18 mg / L) in the dry and rainy season were observed, being in non-compliance with the MPV given by Portaria 2.914. Samples S1 and S2 showed absence of E.coli and values below 0.5 mg / L of N-NO-3. Information on the quality parameters on the labels. The survey of some labels showed that in five bottled watermarks, three of them are contaminated by nitrate according to the MPV (NO-3-N> 10 mg / L). Conclusion ­ The present study demonstrates that drinking water from wells is unfit for human consumption.


Assuntos
Humanos , Animais , Água Subterrânea , Escherichia coli , Neoplasias Gástricas , Poluição da Água , Resíduos Sólidos , Padrão de Potabilidade da Água , Nitratos
14.
Eng. sanit. ambient ; 25(1): 59-67, jan.-fev. 2020. tab, graf
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1090135

RESUMO

RESUMO Apesar da importância da água na Terra, pouco se conhece sobre sua dinâmica no solo e, consequentemente, poucas são as informações sobre sua preservação em quantidade e qualidade. Diante disso, objetivou-se, neste trabalho, gerar informações que dessem subsídio ao entendimento da dinâmica da água no solo em áreas de recarga de nascentes. Para tanto, realizou-se o monitoramento da vazão e da precipitação nas áreas de recarga de duas pertencentes, verificando a relação existente entre os atributos físico-hídricos do solo intimamente relacionados à recarga subterrânea, além das características pedológicas, do uso do solo, da cobertura vegetal e da declividade. Os resultados mostraram que a sinalização de que os Cambissolos apresentam maior capacidade de infiltração e, consequentemente, recarga, em relação aos Latossolos, não se confirmou neste trabalho. Mesmo havendo uma grande discrepância nas classes de relevo entre as áreas de recarga das nascentes, esse efeito não foi suficiente para reduzir o processo de recarga. As condições de uso do solo não foram substancialmente diferentes a ponto de influenciar o processo de infiltração. O grande diferencial entre as áreas de recarga das nascentes em relação à capacidade de gerar deflúvio base se explica pelos atributos físico-hídricos e pelo índice pluviométrico, que, neste caso, resultaram em uma associação mais efetiva na área da nascente L1. A elevada capacidade de retenção de água no Latossolo, reflexo da maior microporosidade associada a sua maior profundidade, é uma característica desfavorável para o processo de recarga quando comparado ao Cambissolo, que tem horizonte B incipiente e menores profundidades.


ABSTRACT Despite the importance of water on earth, little is known about its dynamics in the soil, and consequently, there is little information about its preservation in quantity and quality. Therefore, the objective of this research was to generate information to support the understanding of water dynamics in soil springs in recharge areas. Thus, we carried out monitoring flow and precipitation in the areas of two belonging clearance, verifying the relationship between the physical and water attributes of the soil closely related to groundwater recharge, in addition to soil characteristics, land use, cover vegetation and slope. The results showed that the signaling that Cambisoils have higher infiltration capacity and consequently clearance in relation to Latosols was not confirmed in this study. Even though there is a large discrepancy in relief classes between the recharge areas of springs, this effect was not sufficient to reduce the recharge process. Land use conditions were not substantially different as to influencing the infiltration process. The big difference between the recharge areas of the springs on the ability to generate runoff base is explained by physical-water attributes and rainfall, which in this case resulted in a more effective association in the area of ​​spring L1. The higher water retention capacity of the Oxisol, reflecting the higher microporosity associated with its greater depth, is an unfavorable feature for the recharge process, when compared to Inceptisol, which has an incipient B horizon and lower depths.

15.
Salud colect ; 16: e2325, 2020. graf
Artigo em Espanhol | LILACS | ID: biblio-1139510

RESUMO

RESUMEN Desde mediados de la década de 1990 la agricultura extensiva bajo riego creció aceleradamente en la Argentina. Donde tradicionalmente se producía en secano, la adopción de tecnología creó un nuevo paisaje hídrico: la "tierra irrigada". Para comprender la creación de dicha categoría conceptual y su anclaje dentro de un modelo productivo específico, en este trabajo me propongo analizar la difusión del riego mecanizado en el norte de la provincia de Buenos Aires a partir de las principales políticas públicas que intervienen en esta transformación territorial: el Plan de Mejora Competitiva del clúster de la semilla, el Plan Nacional de Riego y la gestión del agua subterránea para el riego productivo. Recuperando aportes de la ecología política y de los estudios de la ciencia y la tecnología, argumento que la explotación del agua subterránea para riego implica una privatización del recurso que permanece invisibilizada. La "tierra irrigada" contiene dos de los recursos fundamentales para la producción de alimentos que, asociados, se resignifican. El agua adquiere sentido productivo como una mercancía a la que es factible asignar un valor monetario y se privatiza de hecho en el momento de su consumo productivo; mientras la tierra, gracias al agua, se valoriza económicamente al permitir nuevas alternativas de explotación con mayores márgenes de rentabilidad. Así, el agua es el "lubricante" que refuerza el proceso de acumulación.


ABSTRACT Since the mid-1990s extensive agriculture using irrigation has grown rapidly in Argentina. Where farming on dry land was traditionally carried out, technological change has created a new waterscape: "irrigated land." To understand the creation of this conceptual category and how it is anchored in a specific production model, in this paper I contextualize the spread of mechanized irrigation in the north of the province of Buenos Aires by examining the main public policies that intervene in this territorial transformation: the Competitive Improvement Plan of the Seed Cluster, the National Irrigation Plan, and the management of groundwater for productive irrigation. Integrating contributions from Political Ecology and Science and Technology Studies, I argue that the exploitation of groundwater for irrigation implies the privatization of a resource that remains invisible. "Irrigated land" contains two of the fundamental resources for food production that, jointly, resignify each other. Water acquires productive meaning as a commodity to which it is feasible to assign a monetary value, and becomes privatized de facto at the moment of its productive consumption; while the land - thanks to water - is valorized economically by allowing for new exploitation alternatives with higher profit margins. Thus, water acts as the "lubricant" that reinforces the accumulation process.


Assuntos
Humanos , Água , Conservação dos Recursos Naturais , Recursos Hídricos , Mercantilização , Agricultura
16.
Kasmera ; 47(2): 153-173, 02-12-2019. tab, ilus
Artigo em Espanhol | LILACS | ID: biblio-1046358

RESUMO

El agua de consumo humano y su calidad son determinantes para la salud pública. Esta revisión pretende recopilar y analizar información acerca de la relación entre la enfermedad diarreica en niños menores de cinco (5) años y la contaminación de las fuentes de agua subterránea. Se consultaron las bases: PubMed, ScienceDirect, SpringerLink, SciELO y Google Scholar, sin limitación en fechas de publicación; utilizando los descriptores: agua subterránea, diarrea, enfermedad gastrointestinal infantil, contaminación microbiana, calidad del agua, diarrea infantil, agua potable, técnicas moleculares y técnicas bioquímicas, analizándose un total de ciento sesenta y nueve (169) publicaciones. Se encontró relación entre la contaminación microbiana del agua subterránea y la diarrea infantil. El agua subterránea se contamina debido a fugas de fosas sépticas, métodos inadecuados de manejo de desechos y escorrentías de agua de lluvia, determinando la prevalencia de diarrea infantil. De allí, la importancia de monitorear la calidad del agua como factor de riesgo, con la detección y cuantificación de bioindicadores, mediante métodos rutinarios y novedosos, e incorporar intervenciones dirigidas a mejorar la accesibilidad a fuentes de agua controladas y la educación sanitaria en la búsqueda de asegurar la protección del agua y la disminución en la prevalencia de la diarrea infantil. Esta revisión está registrada en PROSPERO bajo el número ID 129254


Water for human consumption and its quality are determinants for public health. This review aims to collect and analyze information about the relationship between diarrheal disease in children under five (5) years of age and contamination of groundwater sources. The bases: PubMed, ScienceDirect, SpringerLink, SciELO and Google Scholar, without limitation on publication dates, using the descriptors: groundwater, diarrhea, childhood gastrointestinal disease, microbial contamination, water quality, childhood diarrhea, drinking water, molecular techniques and biochemical techniques, were consulted, analyzing a total of one hundred sixty-nine (169) publications. A relationship was found between microbial contamination of groundwater and childhood diarrhea. Groundwater is contaminated due to septic tank leaks, inadequate methods of waste management and rainwater runoff, determining the prevalence of childhood diarrhea. From there, the importance of monitoring water quality as a risk factor, with the detection and quantification of bioindicators, through routine and novel methods, and incorporating interventions aimed at improving accessibility to controlled water sources and health education in the search to ensure water protection and the decrease in the prevalence of childhood diarrhea. This revision is registered in PROSPERO under the number ID 129254.

17.
Artigo | IMSEAR | ID: sea-204818

RESUMO

The aim of this work is to study the occurrence of nonylphenol and its ethoxylates in Taiyuan industrial area. The present study has firstly determined best conditions of Nonylphenol and its ethoxylates detection by using High Performance Liquid Chromatography (HPLC) 1100 series, variating solvent, mobile phase and flow: rate. These conditions let secondly the concentration determination of these pollutants in water media. Samples were collected from surface and groundwater in the industrial area of Taiyuan city (Shanxi province). Nonylphenol Ethoxylates (NPEOs) detection was better when solvent and Mobile phase were 2-propanol and Flow rate at 0.1 ml/min. Concentrations of Nonylphenol (NP) and NPEOs found in rivers and wastewaters collectors ranged from 80 to 933 µg/L and 38 to 743 µg/L respectively, while for groundwater, concentrations ranged from 24.6 to 151 µg/L and from 20 to 274 µg/L. These high concentrations found both in surface and groundwater, represent a risk of exposition to endocrine disruptors for humans and aquatic species. Actions should be taken to avoid or reduce the use of those compounds, or industries should apply some treatment before release their wastewater into environment. Attention should be paid especially to groundwater in case of human consumption. Introduction to groundwater way and degradation pathways from surface water to groundwater need to further study.

18.
Univ. sci ; 24(1): 135-163, Jan-Apr. 2019. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1014757

RESUMO

Abstract Population growth and urbanization pose a greater pressure for the treatment of drinking water. Additionally, different treatment units, such as decanters and filters, accumulate high concentrations of iron (Fe) and manganese (Mn), which in many cases can be discharged into the environment without any treatment when maintenance is performed. Therefore, this paper evaluates the effectiveness of vertical subsurface wetlands for Fe and Mn removal from wastewater in drinking water treatment plants, taking a pilot scale wetland with an ascending gravel bed with two types of plants: C. esculenta and P. australis in El Hormiguero (Cali, Colombia), as an example. The pilot system had three upstream vertical wetlands, two of them planted and the third one without a plant used as a control. The wetlands were arranged in parallel and each formed by three gravel beds of different diameter. The results showed no significant difference for the percentage of removal in the three wetlands for turbidity (98 %), Fe (90 %), dissolved Fe (97 %) and Mn (98 %). The dissolved oxygen presented a significant difference between the planted wetlands and the control. C. esculenta had the highest concentration of Fe in the root with (103.5 ± 20.8) μg/g; while P australis had the highest average of Fe concentrations in leaves and stem with (45.7 ± 24) μg/g and (41.4 ± 9.1) μg/g, respectively. It is concluded that subsurface wetlands can be an interesting alternative for wastewater treatment in the maintenance of drinking water treatment plants. However, more research is needed for the use of vegetation or some technologies for the removal or reduction of the pollutant load in wetlands, since each drinking water treatment plant will require a treatment system for wastewater, which in turn requires a wastewater treatment system as well


Resumen El crecimiento de la población y la urbanización imponen una mayor presión al tratamiento de agua potable. Por otra parte, las diferentes unidades de tratamiento, como decantadores y filtros, acumulan altas concentraciones de hierro (Fe) y manganeso (Mn), las cuales, en muchos casos, son descargadas en el ambiente sin ningún tratamiento cuando se hace mantenimiento. Este artículo evalúa la efectividad de humedales subsuperficiales de flujo vertical para la remoción de Fe y Mn provenientes de agua residual en plantas de tratamiento de agua potable, tomando como ejemplo un humedal de flujo ascendente a escala piloto, con un lecho de grava y dos tipos de plantas: C. esculenta y P. australis en El Hormiguero (Cali, Colombia). El sistema piloto consistió en tres humedales verticales de flujo ascendente, dos de ellos plantados y el tercero sin plantas, como control. Los humedales se organizaron en paralelo, cada uno formado por tres lechos de grava de diferente diámetro. Los resultados mostraron que no hubo diferencia significativa en el porcentaje de remoción en los tres humedales para turbidez (98 %), Fe (90 %), Fe disuelto (97 %) y Mn (98 %). El oxígeno disuelto presentó una diferencia significativa entre los humedales plantados y el control. C. esculenta tuvo la concentración más alta de Fe en la raíz, con (103.5 ± 20.8) μg/g; mientras que P. australis tuvo el promedio más alto de concentraciones de Fe en hojas y tallos, con (45.7 ± 24) μg/g y (41.4 ± 9.1) μg/g, respectivamente. Se concluye que los humedales subsuperficiales pueden ser una alternativa interesante para el tratamiento de aguas residuales en el mantenimiento de plantas de tratamiento de agua potable. Sin embargo, se requiere más investigación sobre el uso de vegetación u otras tecnologías para la remoción o reducción de la carga contaminante en humedales, ya que cada planta de tratamiento de agua potable o su sistema de tratamiento de aguas residuales con humedales mantendrá el contaminante en el sistema.


Resumo O crescimento da população e da urbanização impõem uma maior pressão ao tratamento de água potável. Adicionalmente, as diferentes unidades de tratamento, como decantadores e filtros, acumulam altas concentrações de ferro (Fe) e manganês (Mn), as quais, em muitos casos, são liberadas no ambiente durante a manutenção, sem receber nenhum tipo de tratamento. Este artigo avaliou a eficácia de zonas úmidas subsuperficiais de fluxo vertical na remoção de Fe e Mn provenientes das águas residuais de estações de tratamento de água potável, usando como exemplo uma zona úmida a escala piloto com fluxo ascendente, leito de cascalho e dois tipos de plantas, C. esculenta e P. australis, localizada em El Hormiguero (Cali, Colombia). O sistema piloto usou três zonas úmidas verticais de fluxo ascendente, duas delas com plantas e a terceira sem plantas, como controle. As zonas húmidas foram organizadas em paralelo, cada uma sendo formada por três leitos de cascalho de diferente diâmetro. Os resultados mostraram que não houve diferença significativa na porcentagem de remoção das três zonas úmidas em termos de turbidez (98 %), Fe (90 %), Fe dissolvido (97 %) e Mn (98 %). O oxigênio dissolvido apresentou uma diferença significativa entre as zonas úmidas plantadas e a controle. C. esculenta teve a concentração mais alta de Fe na raiz, (103.5 ± 20.8) μg/g, em quanto P. au tralis teve a maior média de concentrações de Fe nas folhas e nos talos, (45.7 ± 24) μg/g e (41.4 ± 9.1) μg/g, respetivamente. Concluiuse que as zonas úmidas subsuperficiais podem ser uma alternativa interessante para o tratamento de águas residuais durante a manutenção de estações de tratamento de água potável. No entanto, mais pesquisa é necessária para determinar a importâncias do uso da vegetação ou outras tecnologias para a remoção ou diminuição da carga contaminante nas zonas úmidas, pois cada estação de tratamento de água potável ou sistema de tratamento de águas residuais com zonas úmidas irá manter oconaminante no sistema.

19.
J Environ Biol ; 2019 Mar; 40(2): 200-210
Artigo | IMSEAR | ID: sea-214581

RESUMO

Aim: The current study aimed to identify the hydro-geological processes that control the groundwater chemistry. Further, groundwater quality was also evaluated for drinking and irrigation purposes. Methodology: Groundwater samples were collected from a semi-arid region of North India i.e., Ellenabad, Sirsa, Haryana. The samples were analyzed following the American Public Health Association standard methods for the examination of water and wastewater. Results: Most of the groundwater samples of study area fall under hard category. The saline nature of groundwater can be attributed to high concentration of total dissolved salts (340±104 mg l-1). Majority of the groundwater samples showed fluoride concentration below the permissible limit of WHO and BIS (1.0 mg l-1). Multivariate analysis including sodium absorption ratio was calculated to assess the water quality for irrigation purpose and it was found appropriate for majority of crops, except for sensitive plant species. Interpretation: Potability assessment of groundwater showed that more than 40% samples were unacceptable for drinking purpose without any prior treatment, hence, it is essential to conduct a routine monitoring of groundwater to determine its aptness for drinking, domestic and agriculture purposes.

20.
Medicina (B.Aires) ; 79(1): 11-19, feb. 2019. graf, tab
Artigo em Espanhol | LILACS | ID: biblio-1002582

RESUMO

El hipotiroidismo subclínico (HS), elevación de tirotrofina con hormonas tiroideas normales, junto al bocio, aumentó la frecuencia en las últimas décadas. Con el objetivo de relacionar la prevalencia de bocio y HS con el consumo de agua subterránea como factor de riesgo etiológico poblacional, se analizaron 879 historias clínicas de un centro médico de Glew, en el conurbano bonaerense Sur. Se estudió la población según edad (20-60 y 12-19 años) y tipo de agua consumida (potabilizada o napa subterránea). El agua subterránea fue consumida por el 70.5% del grupo de 20 a 60 años (n = 559, 79.9% mujeres) y por el 66.3% del grupo de 12 a 19 años (n = 57, 81.4% mujeres). En el grupo de 20 a 60 años la prevalencia de HS en consumidores de agua potabilizada y subterránea fue del 1% y 57.8% (p < 0.0001) y la de bocio de 3.8% y 38.9% (p < 0.0001), respectivamente; con un riesgo atribuible al agua subterránea de 57% para HS y 35% para bocio. En el grupo de 12 a 19 años, la prevalencia de HS fue 6.9% y 52.6% (p < 0.0001) y de bocio 13.8% y 77.2% para los grupos de agua potabilizada y subterránea, (p < 0.0001) respectivamente; con un riesgo atribuible al agua subterránea de 46% para HS y 61% para bocio. El análisis fisicoquímico mostró presencia de nitratos (entre 24 y 83 mg/l) en aguas de pozos y ausencia en agua potable. La prevalencia aumentada de HS y bocio podrían deberse a la acción disruptora tiroidea de los nitratos.


Subclinical hypothyroidism (SH), elevation of the level of thyrotrophin with normal thyroid hormones, along with goiter (glandular size > 25g), increased in recent decades. In order to relate the prevalence of goiter and SH with the consumption of groundwater, as a population etiological risk factor, we analyzed 879 clinical histories from a medical center in the city of Glew in the South Buenos Aires suburbs. The population was studied according to age (20 to 60 and 12 to 19 years) and type of water consumed (potable water or groundwater). Groundwater was consumed by 70.5% of the group from 20 to 60 years old (n = 559, 79.9% women) and by 66.3% of the group from 12 to 19 years old (n = 57, 81.4% women In the group of 20 to 60 years, the prevalence of SH in potable water and groundwater users was 1% and 57.8% (p < 0.0001) and the goiter rate of 3.8% and 38.9% (p < 0.0001) respectively; with an attributable risk to groundwater of 57% for HS, and 35% for goiter In the group of 12 to 19 years, the prevalence of SH was 6.9% and 52.6% (p < 0.0001) and goiter 13.8% and 77.2% for the water and groundwater groups (p>0.0001) respectively, with an attributable risk of 46% for HS y 61% for goiter. The physicochemical analysis showed the presence of nitrates in the range of 24 to 83 mg/l in groundwater and absence in potable water. The increased prevalence of HS and goiter could be due to the thyroid disrupting action of nitrates.


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Adulto Jovem , Água Potável/química , Água Subterrânea/química , Doenças Transmitidas pela Água/etiologia , Bócio/etiologia , Hipotireoidismo/etiologia , Argentina/epidemiologia , Qualidade da Água , Tireotropina/sangue , Prevalência , Estudos Transversais , Fatores de Risco , Análise de Variância , Distribuição por Sexo , Distribuição por Idade , Estatísticas não Paramétricas , Doenças Transmitidas pela Água/epidemiologia , Bócio/epidemiologia , Hipotireoidismo/epidemiologia , Nitratos/análise
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