ABSTRACT
A novel method for the determination of metallic elements in environmental samples was developed based on the matrix-assisted plasma surface sampling atomic emission spectrometry ( AES system) . A piece of filter paper was used as sample substrate. By direct interaction of the plasma tail plume with the filter paper surface, the filter paper absorbed energy from the plasma source and released combustion heating to the analytes originally present on its surface, thus to promote the atomization and excitation process. Surface sampling was performed in both cases of liquid and solid state analytes. Therefore, no flow injection system was required and sample pretreatment process was simplified. The proposed method provides several advantages, including fast analysis speed ( about 240 samples/h ) , little sample consumption (μL or μg level) , simplicity in instrument design, and also ease of system operation. These advantages made it attractive as a potential miniaturized AES system for in situ and high-throughput elemental analyses. Quantitative analysis of metal ions were achieved in this study for elements Ag, Au, Ba, Cd, Cr, Cu, Eu, La, Mn, Ni, Pb, Sr and Y. Under optimal conditions, the LOD values of the 13 elements ranged from 1. 0 to 88 μg/L. The repeatability, expressed as relative standard deviation ( RSD) from 10 replicates, ranged from 2. 3% to 6. 8%. To validate the proposed method, the system was employed to determine metal elements in standard reference materials of environmental samples. The content of each element was well in agreement with the certified values.
ABSTRACT
Introdução: A leptospirose tem emergido como um importante problema de saúde pública no mundo. Esta zoonose é responsável por epidemias anuais que acometem principalmente indivíduos residentes em comunidades negligenciadas como as existentes em Salvador. Poucos estudos longitudinais foram realizados com objetivo de identificar os fatores de risco para infecção, fontes de transmissão e compreender a real dimensão da leptospirose nessas comunidades. Objetivo: Identificar fatores de risco para infecção prévia e novas infecções por leptospiras no contexto ambiental e socioeconômico em uma comunidade em Salvador Bahia. Métodos: Estudos de soroprevalência e coorte foram conduzidos na comunidade de Pau da Lima, com a realização de entrevistas domiciliares, avaliação peridomiciliar, coleta de material biológico e análises espaciais para mensurar a associação epidemiológica entre fatores de risco ambientais e as infecções. O teste de microaglutinação foi utilizado para avaliar amostras sorológicas obtidas. Resultados: Residir próximo aos esgotos abertos e do fundo do vale proximidade do domicílio a acúmulo de lixo e baixa renda foram associados com as infecções. A incidência anual de infecções secundárias foi de 2,3 vezes maior que as infecções primárias. Conclusão: O presente estudo sugere que medidas preventivas devem focalizar nas deficiências de infraestrutura que servem como fontes de transmissão. Intervenções mais efetivas precisam se concentrar especialmente nos adultos jovens e nos grupos populacionais mais desfavorecidos nestas comunidades.
Introduction: Leptospirosis has emerged as an important public health problem in the world. This zoonosis is responsible for annual epidemics affecting mainly individuals living in disadvantaged communities as existing in Salvador. Few longitudinal studies have been conducted in order to identify risk factors for infection, transmission sources and understand the real dimension of leptospirosis in these communities. Objective: To identify risk factors for early infection and new infections by Leptospira in environmental and socioeconomic context in a community in Salvador Bahia. Methods: Seroprevalence and cohort studies were conducted in Pau da Lima community, conducting home interviews peridomicilary review, collection of biological material and spatial analysis to measure the epidemiological association between environmental risk factors and infections. The agglutination test was used to evaluate serum samples obtained. Results: Residing next to open sewers and the valley floor near the homes of waste accumulation and low income were associated with infections. The annual incidence of secondary infections was 2.3 times higher than primary infections. Conclusion: This study suggests that preventive measures should focus on infrastructure deficiencies that serve as sources of transmission. More effective interventions need to focus especially on young adults and the most disadvantaged population groups in these communities.