Heloise Garcia Knapik

Unsupervised component analysis: PCA, POA and ICA data exploring - connecting the dots

Under controlled conditions, each compound presents a specific spectral activity. Based on this assumption, this article discusses Principal Component Analysis (PCA), Principal Object Analysis (POA) and Independent Component Analysis (ICA) algorithms and some decision criteria in order to obtain unequivocal information on the number of active spectral components present in a certain aquatic system. The POA algorithm was shown to be a very robust unsupervised object-oriented exploratory data analysis, proven to be successful in correctly determining the number of independent components present in a given spectral dataset. In this work we found that POA combined with ICA is a robust and accurate unsupervised method to retrieve maximal spectral information (the number of components, respective signal sources and their contributions).

Occurrence and risk assessment of parabens and triclosan in surface waters of southern Brazil: a problem of emerging compounds in an emerging country

Parabens and triclosan compounds are widely used in pharmaceutical products, personal care, food and various products of daily use. After use, the final destinations of these contaminants are domestic effluents and the environment if not collected or treated. The objective of this study was to evaluate the presence of parabens and triclosan in environments in a subtropical region, more specifically in the metropolitan region of Curitiba (southern Brazil) and possible effects of these compounds in aquatic environments through risk assessment through the use of risk quotient (RQ). Samples were collected in 20 points for 4 campaigns. For the extraction of the compounds we used the extraction technique of solid phase extraction (SPE). The determination of the compounds was using gas chromatography coupled to mass spectrometry (GC-MS). It was observed high concentrations of parabens, especially MeP (up to 2875 ng L–1). Despite high concentrations of parabens, their presence has a low risk to aquatic organisms. Triclosan has been observed at higher concentrations (415 ng L–1), suggesting once again that these environments are impacted by human action. The RQ assessed that triclosan has a high risk for certain groups of organisms.

Quali-quantitative characterization of organic matter in urbanized drainage basins as a basis for the application of Water Resources Management Instruments

ABSTRACT The challenge imposed by law no. 9433/97 to establish mechanisms for the recovery of bodies of water led to a dynamic of research that could guarantee not only an adequate understanding of the management instruments but also the technical basis for their application. In this research, emphasis was placed on understanding the dynamics of organic matter (OM) in a drainage basin heavily influenced by anthropogenic activities, through the analysis and interpretation of qualitative and quantitative information. The case study was the Iguacu River basin, from its headwaters in the Metropolitan Region of Curitiba (MRC) to the municipality of Uniao da Vitoria . The results obtained showed a large deposition of labile OM in the MRC coming probably from domestic effluents, with consequent DO depletion and water quality degradation. However, after the more urbanized region, there is a reduction in the concentration of OM and the indication of the predominance of pedogenic material, suggesting that in addition to the dilution effect, there is less input of anthropogenic effluents in this region, which results in an improvement in water quality, represented mainly by the recovery of the DO concentration. The combined use of quantitative data and UV-visible spectroscopy was fundamental to comprehend the variation in the characteristics of OM and its sources along the studied section.

Modelagem de carbono orgânico em rios urbanos: aplicabilidade para o planejamento e gestão de qualidade de água

O objetivo do presente estudo e o de analisar a aplicabilidade de um modelo de transporte e decaimento de carbono orgânico para a simulacao da qualidade da agua em rios urbanos como subsidio para atividades de planejamento e gestao de recursos hidricos. A abordagem conceitual baseia-se na hipotese de que as fracoes particulada, dissolvida, labil e refrataria de carbono orgânico, que diferem na sua composicao em funcao de sua origem no sistema, apresentando distintos mecanismos de degradacao e, consequentemente, no impacto em termos da deplecao da concentracao de oxigenio dissolvido na coluna d’agua. O desenvolvimento do trabalho consistiu na determinacao quantitativa e qualitativa das fracoes de carbono orgânico no rio Iguacu, localizado na Bacia do Alto Iguacu, e no desenvolvimento dos algoritmos de simulacao e calibracao automatica do modelo proposto, denominado ROCS - Model (River Organic Carbon Simulation Model). O modelo foi estruturado em planilhas Excel, com programacao estruturada em VBA (Visual Basic for Applications), considerando escoamento unidimensional em condicoes de regime permanente em rios. O modelo considera multiplas entradas de cargas difusas e pontuais. A calibracao e feita atraves de um algoritmo de otimizacao por colonias de particulas (PSO), utilizando como estudo de caso dados de monitoramento de qualidade da agua em 6 estacoes de controle ao longo de 107 km do rio principal, no Rio Iguacu, localizado em uma area de intensa urbanizacao da regiao de Curitiba- PR, com aproximadamente 3 milhoes de habitantes em uma area de 3.000 km2. Os resultados indicam que a presente abordagem, considerando a simulacao das fracoes de carbono orgânico, tem potencial para ser aplicado em modelos de gestao de recursos hidricos, como alternativas aos parâmetros de qualidade da agua tradicionais previstos na legislacao Brasileira.