Endemic dental fluorosis in children from a brazilian slave-descendent community: a cross-sectional study / Fluorose dentária endêmica em crianças de uma comunidade quilombola brasileira: um estudo transversal

Although fluoride (F) is required for the normal growth and development of several human organs and tissues, excessive exposure to it may be potentially toxic. Groundwater may present ranging levels of F; however, the appearance, taste, and smell are not altered. Thus, the present study aimed to evaluate dental fluorosis in children from a Brazilian slave-descendent community, as well as to assess F levels in the drinking water supplies available in that area. For that, 21 children aged from 6 to 14 years living in Rincão dos Martimianos were invited to participate. Thylstrup and Fejerskov index (a 0­9 scale) was used to assess dental fluorosis on permanent teeth. Furthermore, the F concentration of two water samples (from the artesian well and a tank) was determined by using a potentiometric method. All children presented dental fluorosis to some degree, ranging from score 2 to 9. About 81% of them had dental fluorosis scores equal to or over 5. Scores lower than 5 were observed only in children younger than 8 years; on the other hand, all children older than 8 years presented scores higher than 5. Moreover, artesian well water had an F concentration of 5 mg/L and tank water 0.8 mg/L. It is suggested that the F-rich groundwater supply was most probably responsible for dental fluorosis in that area. Brazilian slave-descendent communities, therefore, should receive constant attention from their local authorities in order to guarantee a proper water supply for consumption, as well as to provide public health education(AU)

Embora o flúor (F) seja necessário para o crescimento e desenvolvimento normal de vários órgãos e tecidos humanos, a exposição excessiva pode ser potencialmente tóxica. As águas subterrâneas podem apresentar níveis variados de F; no entanto, a aparência, o sabor e o cheiro não são alterados. Desta forma, o presente estudo teve como objetivo avaliar a fluorose dentária em crianças de uma comunidade brasileira descendente de escravos, bem como avaliar os níveis de F na água potável disponível nessa área. Para isso, 21 crianças de 6 a 14 anos residentes no Rincão dos Martimianos foram convidadas a participar da pesquisa. O índice de Thylstrup e Fejerskov (uma escala de 0 a 9) foi usado para avaliar a fluorose dentária em dentes permanentes. Além disso, a concentração de F de duas amostras de água (do poço artesiano e de um tanque) foi determinada pelo método potenciométrico. Todas as crianças apresentaram algum grau de fluorose dentária, variando de 2 a 9. Cerca de 81% delas apresentaram escores de fluorose dentária iguais ou superiores a 5. Escores inferiores a 5 foram observados apenas em crianças menores de 8 anos; por outro lado, todas as crianças maiores de 8 anos apresentaram escores superiores a 5. Além disso, a água do poço artesiano tinha concentração de F de 5 mg/L e a água do tanque 0,8 mg/L. Desta forma, acredita-se que a fonte de água subterrânea rica em F foi provavelmente responsável pela fluorose dentária na região avaliada. As comunidades quilombolas brasileiras, portanto, devem receber atenção constante de suas autoridades locais, a fim de garantir o abastecimento adequado de água para consumo, bem como proporcionar educação em saúde pública(AU)

Reusable Enzymatic Strip for Detection of Arsenic

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.

Bibliometric analysis on bioremediation of organic contaminated soil and groundwater based on Web of Science database / 生物工程学报

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.

Community-driven evaluation of E. coli levels in domestic-use underground water sources in Angono, Philippines

@#<p style="text-align: justify;"><strong>Objectives:</strong> The authors considered the community-based on-site water sampling-surveys case-study in Angono, Rizal, in the Republic of the Philippines. The study was designed to determine whether individual citizens within the community could successfully collaborate in order to develop a method for quantification of E. coli levels in water (especially underground water) for domestic use.</p><p style="text-align: justify;"><strong>Methods:</strong> We used techniques that had been validated in Japan for on-site evaluation of E. coli. These simple techniques enabled the on-site quantification of E. coli levels in multiple water sources, including underground water.</p><p style="text-align: justify;"><strong>Results:</strong> The techniques used in Japan were successfully adopted in the Philippines, and we cooperated with regional medical technicians, scientists, and citizens, in order to develop a system where ultimately, the people in Angono can perform all the tasks related to on-site water quality evaluation. From societal and economic perspectives, we were able to reduce the traditionally high laboratory cost (including testing cost and samples transit cost) of coliform bacteria and E. coli evaluation to a lower, fixed cost level that is affordable for regional health centers and other sites.</p><p style="text-align: justify;"><strong>Conclusion:</strong> The transfer of a simple inspection method technology, under the supervision of an experienced Japanese research team, allowed us to validate the E. coli on-site quantification strategy at a regional level as "co-creation of science and society". In addition, beyond technology transfer, our collaborative efforts with scientists, regional medical engineers, and citizens, led to the creation of an NGO (non-governmental organization) that serves citizens in the town of Angono with regard to water quality assessment and certification activities.</p><p style="text-align: justify;"><strong>Key Words:</strong> water quality, water management, community, local people, participatory approach, underground water, Escherichia coli, coliform bacteria, Philippines</p>

Isolation and characterization of hydrocarbon-degrading bacteria from gas station leaking-contaminated groundwater in the Southern Amazon, Brazil / Isolamento e caracterização de bactérias degradadoras de hidrocarbonetos de água subterrânea contaminada por vazamentos em posto de combustível no sul da Amazônia, Brasil

Abstract Twenty-three hydrocarbon-degrading bacteria strains were isolated from gas station leaking-contaminated groundwater located in the Southern Amazon, Brazil. Based on hydrocarbon (diesel, hexadecane, benzene, toluene and xylene) degradation ability, two strains were selected for further study. The amplification and sequencing of the 16S rRNA gene showed that these two strains belonged to the genus Bacillus (Bacillus sp. L26 and Bacillus sp. L30). GC-MS analysis showed that strain L30 was the most effective in degrading n-alkane (C10-C27) from diesel after 7 days of cultivation in mineral medium. Both strains produced biosurfactants and showed emulsification activity, specially the strain L30. Alkane hydroxylase gene (group III), which is important for alkane biodegradation, was present in strains. As a result, this study indicated that these bacteria could have promising applications in hydrocarbon bioremediation.

Resumo Vinte e três linhagens bacterianas degradadoras de hidrocarbonetos foram isoladas de água subterrânea contaminada por vazamento em posto de combustível no sul da Amazônia, Brasil. Com base na habilidade de degradar hidrocarbonetos (diesel, hexadecano, benzeno, tolueno e xileno), duas linhagens foram selecionadas para estudos posteriores. A amplificação e sequenciamento do gene 16S rRNA demonstrou que essas linhagens pertencem ao gênero Bacillus (Bacillus sp. L26 and Bacillus sp. L30). Análises de GC-MS mostraram que a linhagem L30 foi mais eficiente em degradar n-alcanos (C10-C27) presentes no diesel, após 7 dias de cultivo em meio mineral. Ambas as linhagens produziram biossurfactantes e apresentaram atividade emulsificante, especialmente a linhagem L30. O gene alcano hidroxilase (grupo III), o qual é importante para degradação de alcanos, foram detectados nas linhagens. Como resultado, este estudo indicou que essas linhagens bacterianas podem ser promissoras se aplicadas em processos de biorremediação.

Avaliação da contaminação de nitrato e Escherichia coli em água subterrânea no município de Carapicuiba (SP) / Evaluation of nitrate and Escherichia coli contamination on groundwater in the city of Carapicuiba (SP)

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.

Estimativa de contaminação de águas subterrâneas e superficiais por agrotóxicos em área sucroalcooleira, Santa Rita/PB, Brasil / Estimate of the contamination of groundwater and surface water due to agrochemicals in the sugar-alcohol area, Santa Rita, State of Paraíba, Brazil

Resumo O aumento da produtividade agrícola, em especial da produção canavieira, geralmente está associado ao uso de agrotóxicos. O risco de contaminação desses compostos nos recursos hídricos é uma preocupação para a saúde pública e ambiental. Nesse contexto, o estudo objetivou estimar o potencial de contaminação das águas subterrâneas e superficiais por agrotóxicos aplicados em uma área sucroalcooleira na região metropolitana de João Pessoa, município de Santa Rita/Paraíba. A análise foi realizada seguindo critérios propostos pela Environmental Protection Agency - EPA e índice de GUS (águas subterrâneas) e pelo método de GOSS (águas superficiais). Como resultados da estimativa de contaminação das águas subterrâneas, observou-se que dos 25 princípios ativos avaliados pelos métodos (EPA e GUS), 52% apresentaram tendência de contaminação potencial. Quanto ao risco de contaminação das águas superficiais, a maioria dos princípios ativos possuía uma maior tendência de transporte de suas moléculas dissolvidas em água e transportadas por meio do carreamento das águas da chuva. Assim, pode-se concluir que há a necessidade de implantação de programas de monitoramento ambiental e de medidas voltadas à proteção da saúde pública.

Abstract The increase in agricultural productivity, especially sugarcane production, is generally associated with the use of agrochemicals. The risk of contamination of these compounds in water resources is a concern for public and environmental health. In this context, the scope of this study was to estimate the contamination potential of the groundwater and surface water by agrochemicals applied in a sugar and alcohol area in the metropolitan region of João Pessoa, Santa Rita/Paraíba. Analysis was performed according to the criteria proposed by the EPA (Environmental Protection Agency), namely the GUS index (Groundwater Ubiquity Score) and the GOSS method (surface water). As a result of the estimate of groundwater contamination, it was observed that 52% out of 25 active compounds evaluated by the methods (EPA and GUS), showed a tendency of potential contamination. With respect to the contamination of surface waters, most of the active principles had a greater tendency to transport their molecules dissolved in water and transported them through rainwater. Thus, the conclusion drawn is that there is a need for the implementation of environmental monitoring programs and measures aimed at the protection of public health.

Wide diversity of fungal species found in wellwater for human consumption: an analytical cross-sectional study

ABSTRACT BACKGROUND: Fungi are ubiquitous in the environment. They are able to grow in water and many of them may be opportunistic pathogens. OBJECTIVE: The aims were to identify fungi in registered wells (RWs) and nonregistered wells (NRWs) that tap into groundwater; and to correlate the results from physicochemical assays on this water (free residual chlorine and pH) with the presence of fungi. DATA AND SETTING: Analytical cross-sectional quantitative study on groundwater wells in São José do Rio Preto, São Paulo, Brazil. METHODS: 52 samples of 500 ml of water were collected from RWs and 107 from NRWs. These were sent to a microbiology laboratory to identify any fungi that were present. In addition, free residual chlorine and pH were measured immediately after sample collection. Several statistical analysis tests were used. RESULTS: Fungal contamination was present in 78.8% of the samples from RWs and 81.3% from NRWs. Filamentous fungi were more prevalent than yeast in both types of wells. There was no significant difference in presence of fungi according to whether chloride and pH were within recommended levels in RWs; or according to whether pH was within recommended levels in NRWs. Furthermore, there was no statistical difference in the levels of fungal contamination between RWs and NRWs. CONCLUSION: Both RWs and NRWs are potential reservoirs for many types of fungi. Many of these may become opportunistic pathogens if they infect immunosuppressed individuals. Furthermore, this study confirms that fungi are able to grow even when chlorine and pH parameters are within the standards recommended.

Diversidad de especies de micobacterias no tuberculosas aisladas en ambientes acuáticos de la ciudad de General Pico, La Pampa, Argentina / Species diversity of non-tuberculous mycobacteria isolated from aquatic environments of General Pico city, Province of La Pampa (Argentina)

Las micobacterias no tuberculosas (MNT) no solo se estudian por su importancia como patógenos oportunistas, sino también por sus aplicaciones en biotecnología y biorremediación. Nuestro objetivo fue determinar la presencia de micobacterias en los distintos hábitats acuáticos de la ciudad de General Pico (provincia de La Pampa), así como su diversidad. Los porcentajes de muestras positivas a micobacterias fueron los siguientes: 37,5% en el sistema de distribución de agua de red, 32,6% en el acuífero que abastece dicho sistema, 36,8% en el agua proveniente de las precipitaciones, 53,1% en los humedales del área de influencia, 80% en los natatorios cubiertos y 33,3% en las fuentes decorativas ubicadas en plazas públicas. De los 90 aislamientos de MNT obtenidos el 8,9% no logró ser identificado a nivel de especie con los métodos utilizados, que incluyeron pruebas fenotípicas y métodos moleculares. Las especies más frecuentemente aisladas fueron Mycobacterium fortuitum y Mycobacterium gordonae. Algunas especies identificadas han sido reportadas en casos de micobacteriosis en nuestro país, entre ellas M. fortuitum, M. gordonae, M. intracellulare, M. vaccae, M. lentiflavum y M. nonchromogenicum. No se aislaron MNT en muestras de agua de red con concentraciones de cloro activo residual mayores de 0,8mg/l, mientras que en los natatorios la presencia de hasta 1,5mg/l de cloro activo residual no fue una limitante para la proliferación de estos microorganismos. Se puede considerar que la incidencia de micobacterias en los ambientes acuáticos de General Pico es cercana al 35%, y que la presencia de estos microorganismos y su diversidad se ve afectada por el contacto con el hombre y sus actividades, como así también por la existencia de vida animal.

Non-tuberculous mycobacteria (NTM) are studied not only for their importance as emerging opportunistic pathogens but also for their applications in biotechnology and bioremediation. Our aim was to determine the occurrence and diversity of mycobacteria in different aquatic habitats of General Pico city, Province of La Pampa. The percentage of samples with positive cultures for mycobacteria were the following: 37.5% recovered from the water supply distribution system; 32.6% from the aquifer that supplies water to the distribution system; 36.8% from rain water; 53.1% from the two wetlands in the area of influence; 80% from indoor swimming pools; and 33.3% from water fountains in downtown public squares. Of the 90 NTM isolates, 8.9% could not be identified at the species level with any of the used methods, phenotypic tests and molecular methods. Mycobacterium fortuitum and Mycobacterium gordonae were the most frequently isolated species. Some of the identified species such as, M. fortuitum, M. gordonae, M. intracellulare, M. vaccae, M. lentiflavum and M. nonchromogenicum, have been reported in cases of mycobacteriosis in Argentina. Mycobacteria with values higher than 0.8mg/ml of residual active chlorine were not recovered from the drinking water supply network, whereas in the swimming pools the presence of up to 1.5 mg/l was not a constraint. Based on our results, the presence of mycobacteria in aquatic environments is close to 35% and their occurrence and diversity is affected both by contact with man and his activities as well as by the existence of animal life.

Concentración de fluoruro en agua subterránea y su relación con los niveles de calcio sérico en niños residentes en el distrito de Loreto, Concepción, Paraguay / Fluoride concentration in groundwater and its relationship with serum calcium levels in children living in Loreto, Concepción, Paraguay

Como parte del ciclo biogeoquímico, el fluoruro del suelo puede disolverse e ingresar al agua. La Organización Mundial de la Salud y la Norma Paraguaya NP 24 001 80 establecen una concentración máxima de 1,5 mg.L-1 de fluoruro en agua de consumo, pudiendo producir fluorosis cuando es elevada, tal como se encontró en niños residentes de Loreto. Estudios indican que la exposición al fluoruro concomitante al déficit de calcio puede agravar la pérdida de masa ósea, causando fragilidad y fluorosis esquelética. Además, se demostró mediante bioensayos en ratones que el exceso de fluoruro reduce la concentración de calcio sérico, por lo que el objetivo del estudio descriptivo con componente analítico fue elaborar un mapa de distribución espacial de fluoruro del agua subterránea de Loreto y relacionar con la calcemia en niños. Se determinó la concentración de fluoruro en muestras de veintitrés pozos de agua subterránea y el calcio sérico de dieciocho niños en edad escolar, ambos por método normalizado. Se identificaron dos pozos con concentraciones superiores al máximo permitido y en 61% de los niños el calcio sérico fue inferior al valor de referencia. Se encontró una correlación débil entre las variables (r = 0,212). El estudio proporciona información relevante sobre sitios con elevadas concentraciones de fluoruro lo que representa un riesgo para la salud pues aun con ingesta adecuada de calcio, los niños presentaron hipocalcemia. Sería importante incluir en estudios posteriores factores no abordados en esta investigación para una evaluación más completa del riesgo de la población expuesta(AU)

As part of the biogeochemical cycle, soil fluoride can dissolve and accumulate in groundwater. World Health Organization and the Paraguayan Standard NP 24 001 80 establishes of 1.5 mg.L-1 of fluoride in drinking water, which can produce fluorosis when it is higher, as it has been found in children of Loreto. Studies indicate that exposure to fluoride concomitant with calcium deficit may aggravate bone loss, causing frailty and skeletal fluorosis. In addition, it was demonstrated through bioassays in mice that excess fluoride reduces serum calcium concentration, the objective of the descriptive study with the analytical component has become a spatial distribution map of Loreto groundwater and related to calcemia in children. The fluoride concentration was determined in samples from twenty-three groundwater wells and serum calcium from eighteen school-age children, both by standard method. Two points were identified with levels above the maximum allowed and in 61% of the children the serum calcium was lower than the reference value. We found a weak correlation between the variables (r = 0.212). It would be important to include in later studies factors not addressed in this research for a more complete risk assessment of the exposed population(AU)

Prevalência de fluorose dental em regiões abastecidas com água sem suplementação de flúor no território brasileiro: uma revisão sistemática e metanálise / Prevalence of dental fluorosis in regions supplied with non-fluoridated water in the Brazilian territory: a systematic review and meta-analysis

Resumo Trata-se de uma revisão sistemática e metanálise para estimar e comparar as prevalências de fluorose dental em localidades brasileiras abastecidas com água tratada sem suplementação de flúor e em localidades que utilizam de água de origem subterrânea. Em dezembro de 2016 foram buscados estudos transversais em 8 bases de dados incluindo a "literatura cinzenta". As prevalências foram estimadas utilizando modelo misto de efeitos aleatórios considerando as localidades como subgrupo. A heterogeneidade entre os estudos foi avaliada através da estatística I2 e do teste Q de Cochran. Foram encontrados 1.038 registros, dos quais apenas 18 artigos preencheram os critérios de inclusão, sendo submetidos para análise. O modelo metanalítico estimou em 8,92% (IC95%:5,41% até 14,36%) a prevalência de fluorose dental em municípios com água tratada sem suplementação de flúor e em 51,96% (IC95%: 31,03% até 72,22%) em municípios abastecidos por poços artesianos. A heterogeneidade entre os estudos foi alta, I2 = 95% (p < 0,01) no primeiro subgrupo de municípios e I2 = 98% (p < 0,01) no segundo subgrupo. A prevalência foi significativamente maior (p < 0,001) em populações expostas à água de poços artesianos, indicando que a presença de flúor natural em concentrações elevadas representa um fator de risco para a ocorrência de fluorose dental.

Abstract This systematic review and meta-analysis aimed to estimate and compare the prevalences of dental fluorosis in Brazilian cities supplied with non-fluoridated water and in locations that uses groundwater. In December of 2016, cross-sectional studies were searched in eight databases, including the "grey literature". The prevalences were estimated through a mixed random effects model considering the locations as subgroups. The heterogeneity among the studies was assessed with I2 statistics and the Cochran's Q test. A total of 1038 records were found, from which only 18 articles met the inclusion criteria and were subjected to analysis. The meta-analytic model estimated a prevalence of dental fluorosis of 8.92 % (95 % CI: 5.41 % to 14.36 %) in cities supplied with non-fluoridated water, and of 51.96 % (95 % CI: 31.03 % to 72.22 %) in cities supplied by artesian wells. The heterogeneity among the studies was high: I2 = 95 % (p < 0.01) in the first subgroup of cities and I2 = 98 % (p < 0.01) in the second subgroup. The prevalence was significantly higher (p < 0.001) in populations exposed to artesian well water, indicating that the presence of natural fluoride at high concentrations represents a risk factor for the occurrence of dental fluorosis.

Variation of the water table and salinity in alluvial aquifers of underground dams in the semi-arid regio n of Rio Grande do Norte, Brazil / Variação do nível freático e da salinidade do aquífero aluvial em barragens subterrâneas no semiárido do Rio Grande do Norte

Despite the growing progress in the construction of underground dams, there are few studies to evaluate and monitor these reservoirs after their construction. Thus, a research study was carried out to evaluate the water table level in alluvial aquifers and water salinity in four underground dams selected in the Cobras river basin, Parelhas municipality, Rio Grande do Norte. Water level variation was monitored using the traditional method and the Ground Penetrating Radar with generation of 3D virtual models. Water samples were collected between the months of December 2010 and December 2011 for electrical conductivity analysis. The results indicate that the accumulation of groundwater and salinity (expressed by electrical conductivity) in the reservoirs were affected by the spatial position within the hydrographic basin (limited occurrence of alluvial aquifer recharge area in headwater sectors) and the presence of surface reservoirs (upstream dams), which promote a more continuous recharge, greater renovation, and reduction of the salinity of the waters of the alluvial aquifer downstream.

Apesar do crescente avanço na construção de barragens subterrâneas, há poucos estudos de avaliação e monitoramento das barragens subterrâneas após a sua construção. Assim, foi realizada uma pesquisa com o objetivo de avaliar a salinidade da água e a variação do nível freático em aquífero aluvial em quatro barragens subterrâneas selecionadas na microbacia do rio das Cobras, município de Parelhas, RioGrande do Norte. As amostras de água foram coletadas entre os meses de dezembro de 2010 a dezembro de 2011 para análise da condutividade elétrica. A variação do nível da água foi monitorada utilizando método tradicional e o Ground Penetrating Radar com geração de modelos virtuais 3D. Os resultados indicam que a acumulação da água subterrânea e a sua salinidade (expressa pela condutividade elétrica) nos reservatórios foram afetadas pela posição espacial dentro da bacia hidrográfica (ocorrência limitada de área de recarga do aquífero aluvial em setores de cabeceiras do rio) e pela presença de reservatórios superficiais (açudes à montante), os quais promovem uma recarga mais contínua, maior renovação, e redução da salinidade das águas do aquífero aluvial à jusante.

Relación deltre hipotiroidismo subclínico y bocio con el origen del agua consumida por una población del conurbano bonaerense / Relationship of subclinical hypothyroidism and goiter with the origin of water consumed by a population of the Buenos Aires suburbs

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.

Peripheral neuropathy induced by drinking water contaminated with low-dose arsenic in Myanmar

BACKGROUND@#More than 140 million people drink arsenic-contaminated groundwater. It is unknown how much arsenic exposure is necessary to cause neurological impairment. Here, we evaluate the relationship between neurological impairments and the arsenic concentration in drinking water (ACDW).@*PARTICIPANTS AND METHODS@#A cross-sectional study design was employed. We performed medical examinations of 1867 residents in seven villages in the Thabaung township in Myanmar. Medical examinations consisted of interviews regarding subjective neurological symptoms and objective neurological examinations of sensory disturbances. For subjective neurological symptoms, we ascertained the presence or absence of defects in smell, vision, taste, and hearing; the feeling of weakness; and chronic numbness or pain. For objective sensory disturbances, we examined defects in pain sensation, vibration sensation, and two-point discrimination. We analyzed the relationship between the subjective symptoms, objective sensory disturbances, and ACDW.@*RESULTS@#Residents with ACDW ≥ 10 parts per billion (ppb) had experienced a "feeling of weakness" and "chronic numbness or pain" significantly more often than those with ACDW  50 ppb). These data suggest a threshold for the occurrence of peripheral neuropathy due to arsenic exposure, and indicate that the arsenic concentration in drinking water should be less than 10 ppb to ensure human health.

An Norovirus Outbreak at a Local Festival in Chungnam Korea

Noroviruses (NoV) are the major viral pathogen causing epidemic acute gastroenteritis and outbreaks of foodborne and waterborne illness. During the local festival in Chungnam province, group food poisoning occurred outbreak by NoV infections in Jan 2019. In this study, epidemiological analysis and molecular characterization were conducted such as genotyping, phylogeny. The prevalent genotypes of food poisoning events were NoV GII.3 and GII.17, and NoV GII.3 and GII.17 isolates of this study were completely matched in nucleotide sequence comparison of capsid gene region, respectively. In underground water and stream water, various multiple genotypes of noroviruses were detected including NoV GII.3, GII.8 and GI.4 in aquatic environment of the local festival site. Among 32 worker samples, various NoVs of five genotypes (GI.7, GI.8, GII.3, GII.8, GII.17) were detected in 12 samples and expected to causing NoV contaminated by exposure to groundwater. NoV genotype GII.3, which was detected from groundwater 2, was completely consistent with that of patients and workers. Therefore, groundwater within the local festival site could be main cause of food poisoning event. Because NoV outbreaks are caused by fecal to oral transmission, proper management of sewage purification facilities, groundwater and sanitary toilets is required for many visitors, and efforts are needed to maintain clean environment.

Influence of third cemetery location on the quality of domestic and groundwater resources in Benin City, Nigeria

ABSTRACT: The present study investigates impact of burial practices on water quality in Benin City, Nigeria by collecting groundwater samples from boreholes located by the peripheral area of Third Cemetery in Benin City and a reference site approximately 4 km away using standard methods. With the exception of SO4, CaCO3, Fe and DO, the concentrations of other parameters were higher in water samples obtained from the peripheral area of Third Cemetery than that from the reference site. Principal component analysis (PCA) revealed that pH, Fe, and CaCO3 were differentiating parameters related to reference site, similar condition was attributed to SO4 and Mg for site 2 and Pb, Mn, Cu, Ni, Zn and DO for sites 1 & 3. Cluster analysis (CA) placed the reference site as outlier to other sites. Higher concentrations of Cl, NO3, Na, K and BOD5 in samples obtained by cemetery peripheral when compared to reference site and positive correlations among these parameters are indications of impacts of decomposing activities in cemetery upon water quality in underlying aquifer. Limiting water quality index (WQI) computation to pH, EC, Cl, NO3, SO4, Na and BOD5 showed that quality of groundwater obtained from cemetery peripheral is not good for domestic uses

Qualitative assessment of some available water resources in Efon-Alaaye, Ekiti State Nigeria

ABSTRACT: As water is a major life sustainer, hence its portability is of great importance in performing that role well. In this study, various water samples were collected within Efon-Alaaye for both physicochemical and bacteriological tests. A total of nine (9) water samples were taken for analysis with six (6) from various surface sources and three (3) from groundwater sources in the study area. The mean turbidity value, temperature, total dissolved solids (TDS) concentration, hardness and EC are 2.92 NTU, 23°C, 447.8 mg/l, 48.1 mg/l and 138.4 µS/cm respectively. Manganese has mean value of 0.27 mg/l. The concentration of both copper and zinc ranges from 0.07 ­ 0.13 mg/l and 0.16 ­ 0.55 mg/l with an average value of 0.04 mg/l and 0.28 mg/l respectively. Water samples collected were also analyzed for total coliform bacteria and ranged from 1 to 4.6/100 ml with an average value of 3.29 colony/100 ml. On the basis of findings, the physico-chemical analysis reveals that some of the water samples were above the WHO standards for parameters like turbidity and TDS while the bacteriological test reveals that seven (7) of the water samples considered met the WHO requirement of portability while the other two samples contain faecal contaminant as E.coli was discovered, though at reasonable rate

Groundwater quality assessment in a University Sub-Urban Community in Delta State, Nigeria: part a-physicochemical analysis

Abstract: This study provides detailed scientific information on the physicochemical properties of drinking water from groundwater in a Nigerian university sub-urban community. Water samples from boreholes (BHs) and handdrawn wells (HDWs) in the community were collected and analyzed for their biological and physicochemical parameters, and the metals from July 2016 to January 2017 for wet and dry seasons. Results obtained, showed that the physicochemical factors complied with the World Health Organization (WHO) guidelines, except for pH being lower in some locations. In the wet and dry seasons, pH varied from 4.4 to 6.2 and from 4.8 to 6.7 respectively. While the mean value for wet season was 5.7, dry season was 5.9; to give a seasonal mean difference of 0.2.Cd and Pb, in both wells, for many locations, were slightly higher than the prescribed limits. The slight elevated concentrations of Pb and Cd could be attributed to oil exploration activities in the study area. The study recommends the provision of improved drinking water in the community

Physiochemical analysis of municipal solid waste leachate from open dumpsites in Benin City Metropolis

ABSTRACT: Physiochemical assessment of leachate in three open dumpsites in Oluku, Uselu and New Benin in Benin City was carried out in this study using standard methods. The pH of leachate sample from Oluku dumpsite was ultra-acidic (3.4) with electrical conductivity of 1650 µS/cm. However pH of leachate samples (7.4 and 8.6) collected from Uselu Market dumpsite and New Benin dumpsite were in the alkaline range with electrical conductivity of 8600 and 9800 µS/cm. The aforementioned approach was employed at distances of 2m and 5m from the mid-sections of these dumpsites and pH of leachate at a distance of 5m from the three were observed to be in the neutral range. The physiochemical analysis indicated the hazards of open waste dumping, as leachate in these dumping sites contains ammonia, calcium carbonate, nitrate, sulphate and other heavy metals which can percolate and contaminate surface water and ground water thereby, causing negative effects on public health safety and the environment

Assessment of physical and chemical characteristics of surface water from River Niger, Illushi, Edo State, Nigeria

ABSTRACT: The physical and chemical characteristics of River Niger, Illushi an important fishing site in Edo State which is currently impacted by human activities, was investigated between the month of April and November, 2017. Surface water samples were collected from three (3) sampling stations covering a total distance of 2600metres from upstream to downstream, and a total of seventeen (17) physical/chemical parameters were investigated. Findings from this study revealed that Air temperature had an average mean value of 27±0.72 mg/L, Water temperature was 26.21±0.63 mg/L, the river was generally acidic with the average pH of 6.27±0.18, Turbidity was 107.28±30.9, Conductivity was 57.08±8.29, Total Dissolved Solid was 34.9±4.78, Total Suspended Solid was 71.7±21.17 mg/L, Alkalinity was 26.62±4.78 mg/L, Chloride was 17.29±1.41 mg/L, Hardness was 26.81±2.59 mg/L, Phosphate was 2.20±0.09 mg/L, Nitrate was 3.19±0.94 mg/L, Sulphate was 25.81±10.78 mg/L, Calcium was 8.69±1.74 mg/L, Magnesium was 2.66±0.39 mg/L, Dissolved Oxygen was 4.47±0.46 mg/L and Biochemical Oxygen Demand was 7.29±3.25 mg/L. This study depicts that turbidity, dissolved oxygen, biochemical oxygen demand, air, and water temperature were higher than the recommended limit for drinkable water. It, therefore, stresses the need for compliance of environmental laws to prevent the river from further deterioration