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Papers by Larissa Torrezani

Revista Virtual de Química, Dec 21, 2020

Environmental Monitoring and Assessment, 2021

Mercury dynamics in hydroelectric reservoirs have been studied worldwide. In tropical reservoirs,... more Mercury dynamics in hydroelectric reservoirs have been studied worldwide. In tropical reservoirs, especially in those of the Amazon, the influence of geochemistry on Hg levels along this aquatic system is not well understood. The main objective of the present study was to assess the influence of environmental conditions (physical and chemical water parameters, trace element concentrations of sediment and sediment geochemistry) on mercury levels of sediment along the Balbina Reservoir (Amazon basin, Brazil). Sediment was collected along the reservoir and in the main tributaries in May 2015 ( n = 10). These samples were assessed for labile iron (LFe), manganese (LMn), aluminum (LAl) and mercury (LHg) concentrations, total mercury (THg) concentrations, organic matter (OM) content, and granulometry. Concentrations in the sediment were 4–212 (LFe), 2–460 (LAl), 180–613 (LMn), < detection limit–256 (LHg), and 12–307 μg kg −1 dry weight (THg). In general, these concentrations decreased along the reservoir from upstream to downstream, reaching the lowest concentrations in the middle of the lake, and they increased in the sampling points near the dam. The lability and concentrations of mercury were influenced by the concentrations of LFe, LMn, LAl, and the granulometry and OM content of the sediment. Altogether, THg concentrations of sediments of the Balbina Reservoir encompass the range of concentrations of other reservoirs or natural lakes in the Amazon basin (from ten to a few hundred μg kg −1 dry weight).

Revista Virtual de Química, 2020

O crescimento urbano desenfreado que ocorreu em Manaus ate o inicio da decada de 2000, associado ... more O crescimento urbano desenfreado que ocorreu em Manaus ate o inicio da decada de 2000, associado a implantacao do Polo Industrial na decada de 60, resultou na degradacao dos corpos d’agua e as areas do entorno de uma das principais bacias hidrograficas da cidade, a Bacia do Educandos. Os sedimentos atuam como sumidouro tanto de nutrientes quanto de contaminantes, sendo extremamente sensiveis aos impactos antropogenicos. A determinacao do grau de poluicao de um metal requer que a sua concentracao seja comparada com um material de referencia nao poluido. Um dos indicadores utilizados e o indice de geoacumulacao. Nesse sentido, o presente trabalho tem como objetivo determinar a concentracao de metais potencialmente toxicos em sedimentos da Bacia do Educandos utilizando o indice de geoacumulacao. A coleta de sedimento foi realizada em 9 pontos de amostragem, sendo 3 nascentes do igarape principal em fevereiro de 2016. Foram determinadas as concentracoes de Al, Ba, Be, Cd, Co, Cr, Cu, Fe...

Journal of Chemical Engineering and Chemistry, 2016

Journal of the Brazilian Chemical Society, 2011

Electroanalysis, 2011

The presence of contaminants, such as phosphate, in biodiesel, has several drawbacks for instance... more The presence of contaminants, such as phosphate, in biodiesel, has several drawbacks for instance: current engines perform poorly, fuel tanks deteriorate, catalytic conversion is damaged, and particles emission is increased. Therefore, biodiesel quality control is extremely important for biodiesel acceptance and commercialization worldwide. In this context, a bare glassy carbon electrode (GCE) and another chemically modified electrode with iron hexacyanoferrate (Prussian Blue – PB) were developed for determination of phosphate in biodiesel. The LODs of 6.44 and 1.19 mg kg−1, and LOQs of 21.43 and 3.97 mg kg−1 were obtained for the bare GCE and the PB‐modified GCE, respectively. The methodology was employed for analysis of Brazilian biodiesel samples, and it led to satisfactory results, demonstrating its potential application for biodiesel quality control. Additionally, recovery and interference tests were conducted, which revealed that the developed methods are suitable for analysis...

Revista Virtual de Química, Dec 21, 2020

Environmental Monitoring and Assessment, 2021

Mercury dynamics in hydroelectric reservoirs have been studied worldwide. In tropical reservoirs,... more Mercury dynamics in hydroelectric reservoirs have been studied worldwide. In tropical reservoirs, especially in those of the Amazon, the influence of geochemistry on Hg levels along this aquatic system is not well understood. The main objective of the present study was to assess the influence of environmental conditions (physical and chemical water parameters, trace element concentrations of sediment and sediment geochemistry) on mercury levels of sediment along the Balbina Reservoir (Amazon basin, Brazil). Sediment was collected along the reservoir and in the main tributaries in May 2015 ( n = 10). These samples were assessed for labile iron (LFe), manganese (LMn), aluminum (LAl) and mercury (LHg) concentrations, total mercury (THg) concentrations, organic matter (OM) content, and granulometry. Concentrations in the sediment were 4–212 (LFe), 2–460 (LAl), 180–613 (LMn), < detection limit–256 (LHg), and 12–307 μg kg −1 dry weight (THg). In general, these concentrations decreased along the reservoir from upstream to downstream, reaching the lowest concentrations in the middle of the lake, and they increased in the sampling points near the dam. The lability and concentrations of mercury were influenced by the concentrations of LFe, LMn, LAl, and the granulometry and OM content of the sediment. Altogether, THg concentrations of sediments of the Balbina Reservoir encompass the range of concentrations of other reservoirs or natural lakes in the Amazon basin (from ten to a few hundred μg kg −1 dry weight).

Revista Virtual de Química, 2020

O crescimento urbano desenfreado que ocorreu em Manaus ate o inicio da decada de 2000, associado ... more O crescimento urbano desenfreado que ocorreu em Manaus ate o inicio da decada de 2000, associado a implantacao do Polo Industrial na decada de 60, resultou na degradacao dos corpos d’agua e as areas do entorno de uma das principais bacias hidrograficas da cidade, a Bacia do Educandos. Os sedimentos atuam como sumidouro tanto de nutrientes quanto de contaminantes, sendo extremamente sensiveis aos impactos antropogenicos. A determinacao do grau de poluicao de um metal requer que a sua concentracao seja comparada com um material de referencia nao poluido. Um dos indicadores utilizados e o indice de geoacumulacao. Nesse sentido, o presente trabalho tem como objetivo determinar a concentracao de metais potencialmente toxicos em sedimentos da Bacia do Educandos utilizando o indice de geoacumulacao. A coleta de sedimento foi realizada em 9 pontos de amostragem, sendo 3 nascentes do igarape principal em fevereiro de 2016. Foram determinadas as concentracoes de Al, Ba, Be, Cd, Co, Cr, Cu, Fe...

Journal of Chemical Engineering and Chemistry, 2016

Journal of the Brazilian Chemical Society, 2011

Electroanalysis, 2011

The presence of contaminants, such as phosphate, in biodiesel, has several drawbacks for instance... more The presence of contaminants, such as phosphate, in biodiesel, has several drawbacks for instance: current engines perform poorly, fuel tanks deteriorate, catalytic conversion is damaged, and particles emission is increased. Therefore, biodiesel quality control is extremely important for biodiesel acceptance and commercialization worldwide. In this context, a bare glassy carbon electrode (GCE) and another chemically modified electrode with iron hexacyanoferrate (Prussian Blue – PB) were developed for determination of phosphate in biodiesel. The LODs of 6.44 and 1.19 mg kg−1, and LOQs of 21.43 and 3.97 mg kg−1 were obtained for the bare GCE and the PB‐modified GCE, respectively. The methodology was employed for analysis of Brazilian biodiesel samples, and it led to satisfactory results, demonstrating its potential application for biodiesel quality control. Additionally, recovery and interference tests were conducted, which revealed that the developed methods are suitable for analysis...