Proposal of an EPR based method for pollution level monitoring in mangrove sediments

Abstract

O objetivo deste estudo foi o de monitorar o nível de poluição de sedimentos subaquáticos de florestas de mangue utilizando espectroscopias de ressonância paramagnética eletrônica (EPR) e de infravermelho próximo (NIR) e análises químicas. A espectroscopia de EPR foi útil para determinar a presença de radicais livres orgânicos de semiquinonas, bem como, fornecer informações sobre a presença de ferro trivalente em domínios diluídos e concentrados nos espectros das amostras. Concluiu-se que, o uso de EPR e NIR, no intervalo espectral adequado, tornou possível avaliar, de forma não destrutiva, o nível de poluição ambiental em sedimentos subaquáticos costeiros de florestas de mangue. Assim, em um período relativamente curto e imprescindível, as autoridades podem tomar as decisões necessárias a fim de evitar danos ambientais.The objective of this study was the monitoring of the pollution level of underwater mangrove sediments using electron paramagnetic resonance (EPR), near-infrared (NIR) spectroscopy and chemical analyses. EPR spectroscopy was useful to determine the presence of organic free radical semiquinone, as well as, to provide information about the presence of trivalent iron in diluted and concentrated or clustered dominion in the sediment samples spectra. It was concluded that by using EPR and NIR spectroscopy measurement, in the appropriate spectral range, it was possible to nondestructively assess the environmental pollution level of coastline underwater mangrove sediments. Though, in a relatively small period of time, the authorities can take the necessary decisions to avoid environmental damages.

Coupling spectroscopic and chromatographic techniques for evaluation of the depositional history of hydrocarbons in a subtropical estuary

“…The oxidation of high quantities of organic matter by the action of microorganisms can result in conditions that are more reduced. In a polluted environment, certain microorganisms can oxidize organic pollutants and then reduce Fe(III) solid phases to more soluble Fe(II) (Mangrich et al, 2009). This was confirmed using kappa coefficient analysis applied to the EPR results, total AHs, and total PAHs.…”

“…The ANT core presented more features at magnetic fields above 3000 G (Fig. 7, Ib, 6e8 cm and 23e25 cm sections), indicative of a reduced environment (Mangrich et al, 2009), while PC3 revealed a clear distinction between the ANT and PGA sediments. These data suggested that the sediments at the PGA site were more oxidized, compared to those at the ANT site.…”

“…8a). The presence of OFRs is indicative of more anoxic (more polluted) environmental conditions (Mangrich et al, 2009). Additionally, the segregation of PC1 was associated with the Mn(II) ion, indicated by a hyperfine structure of six lines, with a broad signal at around 3500 G (Lesven et al, 2010;Polak et al, 2011), and the Fe(III) ion in an isolated domain, identified by the signals at magnetic fields below 3000 G, with a main signal at around 1500 G. However, Mn(II), characteristic of a reduced environment, was absent in the upper layer (between 0 and 4 cm) of the PGA core.…”

“…These data suggested that the sediments at the PGA site were more oxidized, compared to those at the ANT site. A reduced environment can be indicative of greater pollutant inputs, because the presence of organic contaminants increases microbial activity (Mangrich et al, 2009). …”

Analytical chemistry in Brazil: healthy and growing

“…As this technique is suitable for volatile elements, the authors presented a procedure to generate volatile Co, producing a complex between this element and sodium diethyldithiocarbamate (DDTC). Mangrich et al 139 combined several techniques, such as electron paramagnetic resonance (EPR), near-infrared spectroscopy and chemical elemental analyses, for pollution level monitoring in mangrove sediments. Using EPR it was possible to nondestructively assess the environmental pollution level of coastline.…”