Rozane Valente Marins

Background values for evaluation of heavy metal contamination in sediments in the Parnaíba River Delta estuary, NE/Brazil

This study establishes regional background levels and upper thresholds (geochemical baseline) for Zn, Cu, Pb, Cr, Mn, and Fe from surface samples and profiles taken in 16 sedimentary environments of the Parnaíba River Delta estuary, NE-Brazil. Three approaches were applied to evaluate metal contamination: normalization to Fe, statistical analysis and sediment quality guidelines or environmental assessment criteria (TEL-PEL). Metal concentrations in sediments ranged from 2.4 to 31 mg Zn kg(-1), 1.5 to 48 mg Cu kg(-1), 1.3 to 28 mg Pb kg(-1), 1.5 to 38 mg Cr kg(-1); 145 to 1,356 mg Mn kg(-1), and 0.3% to 2.5% for Fe. All metals showed positive correlations with the <0.63 μm sediment fraction, indicating a significant association with rich lithogenic sources of iron oxide-hydroxides. Results suggest a low probability of adverse effects to the local aquatic biota. The background values of the area were lower than those reported for other areas of the northeastern coast of Brazil.

Geoquímica de fósforo como indicadora da qualidade ambiental e dos processos estuarinos do Rio Jaguaribe - costa nordeste oriental brasileira

Phosphorus geochemistry as a proxy of environmental estuarine processes at the Jaguaribe River, Northeastern Brazil. Sedimentation of different phosphorus geochemical fractions can characterize the natural or anthropogenic processes dominant in the watershed. Selective chemical extraction of different phosphorus geochemical forms in estuarine sediments showed the predominance of inorganic over organic forms suggesting an increase in inorganic phosphorus input from anthropogenic sources. Local hydrochemistry favors the dominance of inorganic ferric and carbonatic phosphorus. Ongoing changes in the estuarine throphy, from mesothrophic to euthrophic, may decrease the immobilization of these forms, increasing dissolved phosphorus and favoring euthrophy. Detritic phosphorus suggests a fluvial origin of this fraction and acts as a tracer of river influence upon the estuary.

Emissão de mercúrio para a atmosfera pela queima de gás natural no Brasil

Increasing natural gas use in Brazil triggered a discussion of its role as a Hg source. We show that Hg emissions to the atmosphere from fossil fuel combustion for power generation in Brazil contribute with 6.2% (4.2 t yr-1) to the total anthropogenic Hg atmospheric emissions, with coal combustion and biomass burning as major sources. Natural gas contributes with 0.04 t yr-1, mostly from electricity generation (88%) and industrial uses (7.6%). Preliminary results on Hg concentrations in natural gas suggest that a large fraction of it is trapped during refining and transport, which may create Hg point sources between extraction and consumption.

A new protocol to detect light elements in estuarine sediments by X-ray microanalysis (SEM/EDS).

The analytical scanning electron microscope (SEM) has been used to determine the presence and distribution of atomic elements in mineralogy. However, the detection of light elements such as carbon is difficult to obtain with standard energy-dispersive X-ray spectrometry (EDS) and usual proceedings for SEM. This study proposes a new protocol to detect calcium carbonate by SEM/EDS using sediments from the Jaguaribe River estuary, NE Brazil, as a model. Handmade gold mounting discs (Au stubs) were used as sample support and samples were adhered with inexpensive glue (Loctite Super_Bonder) or directly disposed on the Au stubs. CaCO(3) and NaCl for chemical analysis were used as control and counterproof to the carbon adhesive tape. Control salts EDS analyses indicate that the method was efficient to detect light elements. Sediments obtained from different depths in the core sampled at the Jaguaribe River estuary consist of particles and aggregates with diverse morphology that covers a wide range of particle or aggregate size. Morphology and dimensions were similar for all core depths. Analysis of samples disposed on gold mounting disc without glue showed that sediment bulk particles usually presented small particles adhering on the surface. Clay minerals were predominant but silica was also often identified. Calcium was a trace element in a small number of sediment bulk particles. Biological and non-biological calcium carbonates, including nanoparticles, were identified in all core depths. X-ray emitted from Au stub did not interfere in the CaCO(3) EDS analysis. Calcium carbonate particles from sediments were identified using this novel approach.

Impact of Drainage Basin Changes on Suspended Matter and Particulate Copper and Zinc Discharges to the Ocean from the Jaguaribe River in the Semiarid NE Brazilian Coast

ABSTRACT da Silva Dias, F.J.; Valente Marins, R., and Parente Maia, L., 2013. Impact of drainage basin changes on suspended matter and particulate copper and zinc discharges to the ocean from the Jaguaribe River in the semiarid NE Brazilian coast. This study aims to understand the fluvial contribution to the estuary and thence to the ocean and the behavior of the suspended particulate matter (SPM) and particulate Cu and Zn during spring tide cycles and during the dry and rainy seasons in 2005, 2006, and 2008, at the Jaguaribe River Estuary, NE Brazil. The distribution of metals concentrations in SPM during dry and rainy seasons suggests a lithogenic origin of aluminum (Al), iron (Fe), and copper (Cu), as a result of erosion and leaching of soils in the drainage basin due to anthropogenic drivers, such as urbanization, shrimp farming, and agriculture. Anthropogenic drivers also affect Zn flows associated with SPM during the dry season. The highest discharges of SPM and particulate metals occurred during rainy periods due higher freshwater volumes observed in the estuarine channel. The results strongly suggest that the high variability of discharges typical of semiarid drainage basins can be underestimated with the use of secondary data, showing the necessity of obtaining data in situ.

Phosphorus partitioning in sediments from a tropical reservoir during a strong period of drought

Monitoring phosphorus (P) concentration in water and sediments in the Castanhão reservoir, under intensive aquaculture, in Northeastern Brazil showed internal process to dominate P cycling following a reduction of reservoir volume due to an extended drought period. A strong negative correlation between soluble reactive phosphorus in surface waters (SRPs) with the reservoir volume results from diminishing dilution capacity; bottom water SRP showed no significant correlation with volume and imply SRP remobilization to surface layers. Total suspended solids (TSS) showed a significant correlation with chlorophyll-a, suggesting change primary productivity following SRP enrichment of surface waters and living cells dominating the TSS. As a result, eutrophication, as established by a trophic state index, was triggered in the reservoir probably enforced by intensive fish farming effluents, whose nutrients accumulated in bottom waters and which became available due to breaking of the thermocline. Since low rainfall periods are typical of the semiarid region and tend to be more frequent and stronger due to climate change, multiple use of reservoirs in NE Brazil should be reevaluated.

Are Women Contributing Equally to the Oceanography Science in Brazil

Brazil has witnessed a huge increase in the number of articles published in international journals, has graduated more people, and displayed better science proxies. In Oceanography, Brazil has built up a complex system of science and technology, that today ranks 13th in the world in terms of scientific publications, according to the Thomson Reuters database; ahead of countries such as Holland and Russia. But this has not generally improved the gender equality in the field. An evaluation of gender in Brazilian oceanography is presented, as well as an investigation of the reasons for the low participation of women in the Brazilian political decisions today, regarding the future of the sea. Between 1995 and 2010, the percentage of women increased from 34 to 45 % in the leadership class, and from 41 to 52 % in the non-leadership class. But within its own class, the percentage of women leaders remained very similar during this period, varying from 29 to 26 %. In marine science, women leadership is even smaller, as viewed from recent initiatives such as the National Institutes of Science and Technology (INCTs) and the National Institute of Oceanic and Waterways Research (INPOH). Although some recent policies have promoted a more democratic selection of students to universities, and probably a better gender equality, specific mechanisms to improve women leadership in the young oceanography field, are still necessary.

Produção científica da área da Química no desenvolvimento da Oceanografia no Brasil

This paper analyses the scientific contribution of chemists and of the Brazilian Chemical Society (SBQ) and its publications to the development of Oceanography in Brazil, as well as major drivers of this participation. A total of 528 articles were analyzed. Most articles (72%) originated in research groups not associated with graduate programs in oceanography. Nearly 50% dealt with the contamination of the marine environment, followed by chemical process studies (32%) and analytical methods development (15%). SBQ journals contributed with 78 articles (14.7% of the total), and rank 1st (QN) and 2nd (JBCS) among scientific journals publishing the analyzed articles.

Determining the Influence of Urbanization on Mangrove Zones of Northeastern Brazil: Characterization of Ceará State Coastal Zone Organic Matter Inputs

Mangrove zones in Brazil are extremely sensitive to impacts from global climate change and urbanization. To understand the effects of urbanization on organic matter inputs in the coastal zone of Ceara State (northeastern Brazil), seasonal campaigns were carried out in two of the most environmentally significant river/mangrove systems within the region: the Coco river, in the metropolitan region of the huge city of Fortaleza, and the Pacoti River, an environmental protection area, without urban influence, on the east coast of the state. Additionally, a spatial study was conducted along the Jaguaribe River, the largest river in the state connected a mangrove area. Organic matter characterization by dissolved organic carbon, spectrofluorescence and fluorescence quenching, and metal complexation capacity shows clearly that under urban pressure, the produced organic matter in mangrove areas is different, proving that carbon budget and pollutant fate have to be revised to take in account this difference.