“…Previous research by Bouillon et al (2002) notes that higher C/N values in sediments suggest greater contributions from terrestrial sources, with values ranging from 7 to 27.3 as in mangrove sediments. Grillo et al (2013) and Costa et al (2014) found a C/N ratio in the present estuary in the Passage Channel, in Vitoria Bay, of between 13 and 36; this indicates a predominance of terrestrial source carbon associated with the entrance of sewage. Thus, mangrove reservoirs, despite being conceptually mixed/transition environments, may have a C/N ratio beyond values that are theoretically intermediate, reflecting periodic shifts between greater marine or continental influence.…”
Section: Discussionmentioning
confidence: 50%
“…Palynological surveys were previously limited to estuarine systems located in the northern region of ES state (Buso et al 2013a, 2013b; Freitas et al 2016). Geochemical records in the Vitoria estuaries were limited to two studies, Grilo et al (2013) and Costa et al (2014). Figure 1Map of the study area showing core positions, depicting geological domains.…”
Marine insertion indicators in the Vitoria estuary (ES) revealed relative variations in sea level during the Holocene in three sediment cores. Sedimentological, geochemical (C/N ratio), and paleontological (shells and palynomorphs) analysis and 14C dating associated five sedimentary facies to different estuarine deposits. A C/N ratio <10 at the core base indicated organic matter of marine origin. Moving up the cores to 110–150 cm, an abrupt increase in C/N to 26–63 in every core suggests the sudden entry of higher plants into the estuary, potentially the moment sea level retreated. High continental (10,743 palynomorphs/g) and low marine palynomorph concentrations (323 palynomorphs/g) suggest a primarily continental source even during transgression and at high sea level. Around 8973 cal BP, an open bay already existed in the region of Vitoria. Sea level potentially exceeded the current level around 7110 cal BP. The transgressive maximum was at 5567 cal BP. Marine insertion indicators, such as marine shells, low C/N ratios and foraminiferal linings, did not always respond directly to sea level oscillations. These discrepancies probably result from lateral variations in sedimentary deposits from transport patterns and from variations in organic matter and palynomorph preservation due to differences in river and obstacle proximity.
“…Previous research by Bouillon et al (2002) notes that higher C/N values in sediments suggest greater contributions from terrestrial sources, with values ranging from 7 to 27.3 as in mangrove sediments. Grillo et al (2013) and Costa et al (2014) found a C/N ratio in the present estuary in the Passage Channel, in Vitoria Bay, of between 13 and 36; this indicates a predominance of terrestrial source carbon associated with the entrance of sewage. Thus, mangrove reservoirs, despite being conceptually mixed/transition environments, may have a C/N ratio beyond values that are theoretically intermediate, reflecting periodic shifts between greater marine or continental influence.…”
Section: Discussionmentioning
confidence: 50%
“…Palynological surveys were previously limited to estuarine systems located in the northern region of ES state (Buso et al 2013a, 2013b; Freitas et al 2016). Geochemical records in the Vitoria estuaries were limited to two studies, Grilo et al (2013) and Costa et al (2014). Figure 1Map of the study area showing core positions, depicting geological domains.…”
Marine insertion indicators in the Vitoria estuary (ES) revealed relative variations in sea level during the Holocene in three sediment cores. Sedimentological, geochemical (C/N ratio), and paleontological (shells and palynomorphs) analysis and 14C dating associated five sedimentary facies to different estuarine deposits. A C/N ratio <10 at the core base indicated organic matter of marine origin. Moving up the cores to 110–150 cm, an abrupt increase in C/N to 26–63 in every core suggests the sudden entry of higher plants into the estuary, potentially the moment sea level retreated. High continental (10,743 palynomorphs/g) and low marine palynomorph concentrations (323 palynomorphs/g) suggest a primarily continental source even during transgression and at high sea level. Around 8973 cal BP, an open bay already existed in the region of Vitoria. Sea level potentially exceeded the current level around 7110 cal BP. The transgressive maximum was at 5567 cal BP. Marine insertion indicators, such as marine shells, low C/N ratios and foraminiferal linings, did not always respond directly to sea level oscillations. These discrepancies probably result from lateral variations in sedimentary deposits from transport patterns and from variations in organic matter and palynomorph preservation due to differences in river and obstacle proximity.
“…According to Costa et al (2015), Baptista Neto et al (2013, and Duquesne et al (2006), the disposal of domestic sewage and urban solid wastes, such as batteries, in unsuitable places, are important sources of Hg, Zn, Pb, Ni, Cu, and Cr, and these are the major trace metal sources to estuaries bordering metropolitan areas along the EBZN.…”
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“…Emission factors for Hg (0.03-0.04 kg.km −2 .yr −1 ) and kg.km −2 .yr −1 ) are among the highest from anthropogenic sources 2011;Lacerda and Marins, 2006;Torres, 2009; Frontiers in Earth Science frontiersin.org 2013; Paula Filho et al, 2014;Rios et al, 2016;Moura and Lacerda, 2018). According to Costa et al (2015), Baptista Neto et al (2013, and Duquesne et al (2006), the disposal of domestic sewage and urban solid wastes, such as batteries, in unsuitable places, are important sources of Hg, Zn, Pb, Ni, Cu, and Cr, and these are the major trace metal sources to estuaries bordering metropolitan areas along the EBZN.…”
Section: Major Anthropogenic Sources Of Trace Metals In the Ezbnmentioning
The present study provides an overview and assessment of the metals and trace metals registered in water, sediment, and biota in estuaries of the Equatorial Zone of the Brazilian Northeast (EZBN). The study aims to compare the degree of contamination and highlight necessary complementary research. The EZBN is characterized by the transition between the humid and hot Amazonian climate and the hot and dry semiarid climate. The spatial distribution identified enrichment for Cu, Pb, Zn, Hg, and Fe in the sediment, and sequential extraction of metals suggested low to medium mobility of metals along the environments. The Parnaíba River Delta, Curimataú, and the Anil and Bacanga estuaries were the environments with the lowest sediment quality for Pb, Zn, Cu, and Fe, identified by the geoaccumulation index (Igeo). The deposits in these estuaries were related to anthropogenic contributions from domestic sewage and inadequate disposal of wastewater from shrimp farms. However, more studies to determine the natural background levels based on sediment cores and metal speciation are necessary to better differentiate between natural and anthropic sources. Oysters, carnivorous fishes, and crustaceans had the best feedback as biomonitors for Cu, Pb, Zn, and Hg, but the application of biomonitoring needs to be expanded and maintained so that the potential for environmental degradation, which can have significant consequences both for the ecosystem and for human health, can be closely monitored in the EZBN estuaries.
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