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The cathodic adsorptive electrochemical behavior of guanine in the presence of some metal ions at the static mercury drop electrode was investigated. A 1.0x10(-3) mol l(-1) NaOH or a 2.0x10(-2) mol l(-1) Hepes buffer at pH 8.0 solutions were used as supporting electrolytes. The reduction peak potential for guanine was found to be around -0.15 V, which is very close to the mercury reduction wave. A new peak appears at -0.60 V in the presence of copper or at -1.05 V in the presence of zinc. A square wave voltammetric procedure for electroanalytical determination of guanine in 2.0x10(-2) mol l(-1) Hepes buffer at pH 8.0 containing 1.6x10(-5) mol l(-1)of copper ions, was developed. An accumulation potential of -0.15 V during 270 s for the prior adsorption of guanine at the electrode surface was used. The response of the system was found to be linear in the range of guanine concentration from 6.62x10(-8) to 1.32x10(-7) mol l(-1) and the detection limit was 7.0x10(-9) mol l(-1). The influence of DNA bases such as adenine, cytosine and thymine was also examined. Cyclic voltammetry was used to characterize the interfacial and redox mechanism.

The closing down of a lindane factory near Rio de Janeiro, over 45 years ago, left an area heavily contaminated with hexachlorocyclohexane (HCH). Remediation by soil liming was applied by government authorities in 1995. This study aims to evaluate the HCH distribution and impact on soil microbiota due to contamination and liming. Microcosm experiments with uncontaminated soil mixed with HCH and lime indicated that lime-promoted dechlorination of HCH molecules led to leaching and volatilization of metabolites. The treatment applied transformed but did not solve the problem as most of the HCH remains in the soil. Reduced microbial respiratory activity was measured in contaminated field samples. Higher respiration rates in uncontaminated soil were reduced by HCH and lime addition; the sole addition of HCH caused a temporary increase in soil respiration, and stimulation occurred with oxygen and/or nutrient addition. A heterotrophic bacterial population around 109 CFU/g was found in polluted field soil, some well-known degraders having been isolated. Native soil microbiota showed resistance to high amounts of HCH and alkaline pH. The results allow considering bioremediation rather than chemical treatments to clean up the area.

The goal of the present work was to test the hypothesis that inorganic species of copper may inhibit primary production in upwelling waters from the Cabo Frio region. Water samples were collected from four different depths up to 50 m at three stations of Cabo Frio and nutrient concentration, pH, dissolved oxygen, alkalinity, seston, chlorophyll a, primary production, NPP, copper speciation, Cu(II) and Cu(I) and complexing capacity were determined. The results indicate that the rate of photosynthesis in nutrient rich waters with higher copper content and lower complexing capacity is significantly reduced. Cu(I) made up 2-15% of the total copper, however, there was no evidence to suggest that the photochemical production of Cu(I) affects NPP. O objetivo deste trabalho foi testar a hipótese de que espécies inorgânicas de cobre poderiam atuar como um fator inibidor da produção primária nas águas de ressurgência de Cabo Frio. Para tal, amostras de água foram coletadas de quatro profundidades diferentes em três estações costeiras ao largo de Cabo Frio, nas quais determinou-se a concentração de espécies macronutrientes, pH, oxigênio dissolvido, alcalinidade, concentração de material particulado, clorofila a, produção primária, especiação de cobre (Cu(II) e Cu(I)) e a capacidade de complexação. Os resultados indicam que a taxa de fotossíntese em águas ricas em nutrientes, mas com mais altas concentrações de cobre e baixas capacidades de complexação, são significantemente reduzidas. Cu(I) constituiu de 2 a 15 % do cobre total, embora não se tenham encontrado evidências de que a sua produção fotoquímica afete a produtividade primária.

The present work aimed at investigating the effects of growing eutrophic conditions and soil occupation on the carbon storage in Guanabara Bay. Sterols in dated sediment cores were used to characterize the sources of organic matter to the bay. Dinosterol was the most abundant amongst the measured sterols reaching 64.7 % of the total. Coprostanol, a fecal sterol, was present in concentrations as high as 40 µg g-1 in areas of intensive sewage discharge. These results are in agreement with the known elevated primary production in the bay and with the severe eutrophic conditions. The calculated carbon fluxes using the organic carbon content and the sedimention rates range between 50 g C m-2 year-1 and 500g C m-2 year-1 during the last 100 years. O presente trabalho tem como objetivo investigar o efeito do aumento da eutrofização e do uso e ocupação do solo sobre a estocagem de carbono na baía de Guanabara. As concentrações de esteróis ao longo do perfil sedimentar foram usadas para caracterizar a origem da matéria orgânica. O dinosterol foi o esterol mais abundante, representando o máximo de 64,7 % do total. O coprostanol, um esterol de origem fecal, foi encontrado me concentrações máximas de 40 µg g-1 em áreas de intenso aporte de esgotos. Os resultados encontrados são condizentes com a alta produtividade primária da baía e as condições extremas de eutrofização no local. De acordo com as concentrações de carbono orgânico e as taxas locais de sedimentação, foi calculado que o fluxo de carbono orgânico para o sedimento aumentou de 50 g C m-2 ano-1 para 500 g C m-2 ano-1 ao longo dos últimos 100 anos.

Sediments from Guanabara Bay, sampled as short-cores (50–60 cm) from eight stations, were analysed for the elemental (C and N), isotopic (δ13C and δ15N) and molecular composition (steroids) of the organic matter. The objective of this study was to examine whether there are changes in the sources of sedimentary organic matter pool due to increasing N, P and particulate loads to the bay over the last 100 years. On average, we found a 10-fold increase in the flux of organic matter to the sediments with a maximum of 41.7 mol C m−2 year−1. C/N and δ13C time–space distribution and mass balance calculations indicate that the organic material results from a mixture of marine, terrestrial and estuarine sources, with a growing predominance of autochthonous inputs in recent years. Dinosterol was predominant in most samples (>50% of all measured sterols). Concentrations of dinosterol increased significantly in the last two decades and reached values as high as 150 μg g−1 dry sediment. Net increases in concentration were estimated using the first-order decay rate constants derived from experimental data. There are strong indications that an increase in carbon storage occurred in response to growing eutrophic conditions. In spite of the high respiration rates occurring in the water column, fast sedimentation rates result in the transfer of a significant carbon fraction to the anoxic sediments. Further decomposition proceeds only in the first 10 cm of sediment as indicated by the decay rates.

In this paper, flame atomic absorption spectrometry was used for the determination of silver in various materials. The proposed preconcentration method is based on the continuous precipitation of silver as p -dimethylaminobenzilidene–rhodanine (PDBR) complex and dissolution of the precipitate with potassium cyanide. EDTA was added to the sample solution to mask large concentrations of Fe(III), Ni(II), Cu(II), Zn(II), Pb(II), Co(II) and Al(III). An enhancement factor of 20 was obtained for a preconcentration time of 3 min, resulting in a sampling frequency of 16 h −1 . The detection limit (3 σ ) in the sample solution was 5 ng ml −1 . The relative standard deviation at 30 ng ml −1 level was 4.7%. Analytical results obtained for alloy, biological reference material and ore samples analyzed were in good agreement with the certified values and comparable to those obtained with other techniques.

A survey was performed in the hydrological system of the Salobo 3A region, in the Carajás Mining Province, to obtain baseline data on the water chemistry, on the copper concentration and copper speciation, and to evaluate the first environmental impacts derived from anthropogenic activities. Measurements included copper concentration and speciation and a number of essential parameters to characterize water and sediment matrices. The natural background Cu concentration in Salobo waters is around 50-60 nmol L-1 while in the vicinities of the mining complex it reaches more than 300 nmol L-1. In sediments, concentrations ranged between 61 to 1.744 mug g-1. The mining activities at pilot scale resulted in substantial change in the copper distribution between particulate and dissolved phases, as well as in the dissolved copper speciation. Concentration of major water components is low compared to North America and world river average. Realizou-se um estudo ambiental no sistema hidrológico da região do Salobo 3A, localizada no Distrito Mineral de Carajás, com o objetivo de obter dados sobre a química das águas, sobre a distribuição de concentração e especiação do cobre e de avaliar os primeiros impactos derivados de atividades antrópicas. As medições incluíram um número de parâmetros considerados essenciais à caracterização das matrizes. Encontrou-se que a concentração natural de cobre nas águas do Salobo estão próximas de 50-60 nmol L-1, enquanto nas vizinhanças do complexo de mineração os valores encontrados ultrapassam 300 nmol L-1. As concentrações de cobre nos sedimentos encontraram-se na faixa de 61 a 1,744 mig g-1. Além de efeitos sobre a concentração total , as atividades piloto de mineração também alteraram a distribuição do cobre, entre particulado e solução, e a sua especiação nesta fase. De modo geral, as concentrações de solutos principais estão abaixo da média mundial registrada para os rios.

There are indications that the widespread use of organotin compounds (TBT and TPT) as antifoulings, as stabilizers in plastic and as pesticides, has severely affected several species of marine organisms. The most striking effect of TBT and TPT as hormonal disruptors is the development of male organs in females of gastropods, currently denominated imposex. This syndrome can lead to the sterilization and death of affected organisms. The present work gives an overview of the present state of knowledge on imposex occurrence and reports results of a survey conducted in Guanabara Bay, Rio de Janeiro and in several sites along the coast of Fortaleza, Ceará State. Different stages of imposex development were verified in this survey, however, the most prominent levels appeared associated to known spot sources of TBT and TPT. Existem evidências de que a utilização amplamente disseminada de compostos organoestânicos ( TBT e TPT) como antiincrustantes, estabilizadores em plásticos e como pesticidas tenha afetado severamente diversas espécies de organismos marinhos. O mais característico efeito do TBT e do TPT como desreguladores endócrinos é o desenvolvimento de caracteres sexuais masculinos em fêmeas de gastrópodos, conhecido como imposex. Esta síndrome pode levar à esterelização e morte dos organismos afetados. O presente trabalho apresenta uma vista geral ao estado atual do conhecimento sobre a ocorrência do imposex, e reporta os resultados de um estudo conduzido na Baía de Guanabara, Rio de Janeiro, e ao longo da costa de Fortaleza, no Ceará. Diferentes estágios de desenvolvimento do imposex foram verificados neste estudo, os mais proeminentes parecendo associados às fontes pontuais locais conhecidas de TBT e TPT.

Aliphatic (n-C12-n-C40, unresolved complex mixture, resolved peaks) and aromatic hydrocarbons (46 PAH) were investigated in suspended particulate matter (SPM) sampled over eleven months in six of the major rivers and two channels of the Guanabara Bay Basin. PAH flow rates of the most contaminated rivers, the contribution to the PAH sediment load of the receiving bay, and the main sources of hydrocarbons were determined. PAH (38) ranged from 28 ng L(-1) to 11,514 ng L(-1). Hydrocarbon typology and statistical evaluation demonstrated contribution of distinct sources in different regions and allowed quantification of these contributions. Total flow rate for the five major rivers amounts to 3 t year(-1) and responds for 30% of the total PAH annual input into the northern area of the Guanabara Bay. For the first time PAH mass deposited in the bay sediments has been estimated and shall serve as base for decision making and source abatement.

An electrochemical stripping procedure is described for trace measurements of adenine by adsorption on a static mercury drop electrode. Cyclic voltammetry was used to characterize the interfacial and redox behavior. Optimum experimental conditions were found when using a 0.001 M NaOH solution, initial potential of + 0.01 V, scan rate of 5 mV s−1 and linear scan mode. The response of free adenine is linear over the concentration range 0.25–1.25 ppm. Linear scan voltammetry, without accumulation yields a detection limit of 55 ppb adenine. Proper conditions were tested to measuring adenine in presence of guanine, acridine orange, copper, zinc and ssDNA.

An electrochemical stripping procedure for trace measurements of thymine is described by adsorption on a static mercury drop electrode. Cyclic voltammetry was used to characterize the interfacial and redox behavior. Optimum experimental conditions were found to be the use of a 0.005M NaOH solution, an initial potential of −0.08 V, a scan rate of 100 mV.s−1 and a linear scan mode. The response of free thymine is linear over the concentration range 0.1–0.5 ppm. Linear scan voltammetry, without acumulation time yields a detection limit of 62 ppb thymine. Acridine orange and copper were also investigated for measuring thymine in the presence of guanine.

Phosphorus speciation was performed in sediments and waters from an area of 20 km2 under the influence of untreated sewage released via a submarine outfall. Results showed that the pool of organic and non-apatite P made up the major fraction of sewage derived P. A good correlation between Pnapat and FeDBC indicated that sorption on iron oxides is an important mechanism for removal of P to the sediments. Mass balances revealed that most of the sewage derived P had been exported from the observation area but, in spite of this, concentrations of labile forms of P reaching 1900 μg P g−1 were amongst the highest reported for polluted estuarine sediments. The supply over 20 yr of high nutrient loads would have been sufficient to produce 500 000 t of fixed carbon, of which 2% lies presently in the sediments of the surveyed area.

Colorectal cancer (CRC) is a common condition and represents a lethal disease, following a sequential progression from adenoma to carcinoma. Interfering with such natural history of CRC offers clues to prevention and cure, but current screening methods for CRC are still limited by unsatisfactory sensitivity and specificity. Novel diagnostic, prognostic tools are therefore being actively investigated for CRC. The discovery of microRNAs (miRNAs) has led to active research focusing on their role in cancer and several crucial pathways involving angiogenesis, cancer-stem-cell biology, epithelial-mesenchymal transition, formation of metastasis, and drug resistance. MiRNAs might soon represent novel prognostic and diagnostic tools in patients at high risk of CRC or being diagnosed with CRC. MiRNA might prove useful also as therapeutic tools, since dysregulation of miRNAs in cancer cells results in higher levels of messenger RNA (mRNA) specific to tumor promoter genes or tumor suppressor genes. Thus, novel anticancer therapies might originate from manipulation of oncogenic or tumor suppressor miRNAs in CRC. In this review, the innovative aspects of miRNA are discussed, with respect to biogenesis, their role in CRC, and their potential use as biomarkers. Before miRNAs can become available in the clinical setting, however, a number of large prospective studies are still required.

The present study evaluates the potential of Hymeniacidon heliophila as bioindicator of PAH contamination. For this, concentration of 33 PAH was determined in organisms from sites with different contamination level including the heavily polluted Guanabara Bay, Rio de Janeiro, and less impacted coastal areas. PAH concentration and typology were determined in sponges collected from different depths and in two different seasons. The brown mussel broadly studied as bioindicator was also sampled from the same sites for comparison. Both species provided similar information on total PAH concentration which is related to site contamination level. Sponges, however, revealed slight tendency to accumulation of combustion-derived PAH in relation to petrogenic compounds. Differences in PAH typology between species may derive from the interspecific variation in particle size ingestion. Different hydrocarbon typologies were observed in sponges from dry and wet season and PAH concentration varied with depth. H. heliophila may be used as an alternative approach to investigate the presence and sources of PAH in estuarine areas.

The accumulation history of combustion products from the metropolitan area around Guanabara Bay was evaluated using black carbon and polycyclic aromatic hydrocarbons as indicators. BC concentration varied between 0.23 and 0.51%, with an increasing mass accumulation tendency over the last 118 years, whereas a decrease in the values of the ratio BC/organic carbon was observed in the upper sediment layers, probably reflecting the enhancement of bay's eutrophication process in the last 30 years. Higher concentrations of pyrolytic PAH were observed between 1925 and 1976, being consistent with the subsequent deforestation, urbanization, and industrialization that occurred in the Guanabara basin in the period. These PAHs were best characterized by the BFl/(BFl+BePy) diagnostic ratio. The data obtained allowed the characterization of the main events that influenced the combustion patterns in the region: burning of biomass and fossil fuel, economic crisis of 1970 and 1990 and the introduction of ethanol in the Brazilian energetic matrix., Journal of the Brazilian Chemical Society, 24 (11), ISSN:0103-5053

The stromal progenitors of mesodermal cells, mesenchymal stromal cells (MSCs), are a heterogeneous population of plastic adherent fibroblast-like cells with extensive proliferative capacity and differentiation potential. Human MSCs have now been isolated from various tissues including bone marrow, muscle, skin, and adipose tissue, the latter being one of the most suitable cell sources for cell therapy, because of its easy accessibility, minimal morbidity, and abundance of cells. Bone marrow and subcutaneous or visceral adipose tissue samples were collected, digested with collagenase if needed, and seeded in Iscove's medium containing 5% human platelet lysate. Nonadherent cells were removed after 2-3 days and the medium was replaced twice a week. Confluent adherent cells were detached, expanded, and analyzed for several biological properties such as morphology, immunophenotype, growth rate, senescence, clonogenicity, differentiation capacity, immunosuppression, and secretion of angiogenic factors. The results show significant differences between lines derived from subcutaneous fat compared to those derived from visceral fat, such as the higher proliferation rate of the first and the strong induction of angiogenesis of the latter. We are convinced that the identification of the peculiarities of MSCs isolated from different tissues will lead to their more accurate use in cell therapy.

The tissues of corals deposit an aragonite exoskeleton beneath their outer living film at a rate dependent on growth and hence on environmental conditions. This typically results in annual (seasonal) bands being formed within colonies. By analysing molecular organic markers within these bands, our research suggests that coral skeletons record contamination from oil and potentially could be used to investigate other anthropogenic and biogenic organic inputs. Our analyses of sections from within corals (Porites lutea) sampled from the Gulf coasts of Kuwait and Saudi Arabia demonstrate discrete bands of oil contamination which, using selected terpenoid biomarkers, can be source-indexed to specific oil fields (i.e. Kuwait, Iranian or Arabian crude oils). Together with dating using microscopic and X-ray inspection, this offers the potential to investigate contamination during recent years. Further research is, however, necessary to elucidate degradation mechanisms during, and following, the occlusion process of organics within coral skeletons.

An analytical flow-injection procedure based on PbSO4 colloidal formation is proposed as a turbidimetric determination of sulphate in natural waters. Ethanol-water was used as a medium in order to improve the sensibility of the method. Both chemical and flow variables as well as interfering species were studied. A detection limit of 0.3 μg SO2−4 ml−1 was found, and the analytical range (according to Beer's law) was 2–20 μg SO2−4 ml−1. The precision was better than 3% R.S.D. and the sample throughput was ca. 35 h−1. The method, when compared with a standard methodology, gave good results when applied to water analysis.

Cultured and native brown mussels ( Perna perna Linnaeus 1758) were used to evaluate the contamination by PAHs in the SE Brazilian coastal zone. Mean concentrations of total PAH (38 parental and alkylated compounds) and cluster analysis revealed that: (i) mussel farms (32.7–70.1 ng g −1 ) are located in uncontaminated areas; (ii) coastal rockyshore areas (89.7 ± 25.8 ng g −1 ) have low level of contamination; and (iii) the Guanabara Bay (760.9 ± 456.3 ng g −1 ) is chronically contaminated by hydrocarbons, which is consistent with previous results. PAH profiles and diagnostic ratios suggested mixed petrogenic and pyrolitic sources for group (ii) and petrogenic sources for group (iii). The levels of PAH in the cultured and native mussels are below threshold values for safe food, even in Guanabara Bay, and thus in such cases other contaminants and pathogens should be considered in order to evaluate the quality of shellfish for human consumption.

Aliphatic hydrocarbons and 39 PAH (parental and alkylated homologs) determined in ca. 100 sediment samples from the Guanabara Bay, Rio de Janeiro, were evaluated for source discrimination using new approaches. Concentrations of total PAH were in the range of 96–135,000 μg kg −1 similar to other coastal urbanized embayment. Traditional diagnostic ratios were not as efficient PAH source indicators, e.g. biomass combustion was assigned as the major source of the pyrolytic PAH although the hydrographic basin is highly industrialized and urbanized. It is proved petrogenic imprint cannot be detected if only the 16 USEPA PAH are determined. The high production in the eutrophic system is not apparent in the aliphatic fraction dominated by land derived n -alkanes due to the effectiveness of microbial degradation. The present work demonstrates the complexity of hydrocarbon forensics when applied to chronically contaminated environments.

Two strains of moderately halophilic bacteria were grown in aerobic culture experiments containing gel medium to determine the Sr partition coefficient between dolomite and the medium from which it precipitates at 15 to 45°C. The results demonstrate that Sr incorporation in dolomite does occur not by the substitution of Ca, but rather by Mg. They also suggest that Sr partitioning between the culture medium and the minerals is better described by the Nernst equation (DSrdol=Srdol/Srbmi), instead of the Henderson and Kracek equation (DSrdol=(Sr/Ca)dol/(Sr/Ca)solution. The maximum value for DSrdol occurs at 15°C in cultures with and without sulfate, while the minimum values occur at 35°C, where the bacteria exhibit optimal growth. For experiments at 25, 35 and 45°C, we observed that DSrdol values are greater in cultures with sulfate than in cultures without sulfate, whereas DSrdol values are smaller in cultures with sulfate than in cultures without sulfate at 15°C.Together, our observations suggest that DSrdol is apparently related to microbial activity, temperature and sulfate concentration, regardless of the convention used to assess the DSrdol. These results have implications for the interpretation of depositional environments of ancient dolomite. The results of our culture experiments show that higher Sr concentrations in ancient dolomite could reflect microbial mediated primary precipitation. In contrast, previous interpretations concluded that high Sr concentrations in ancient dolomites are an indication of secondary replacement of aragonite, which incorporates high Sr concentrations in its crystal lattice, reflecting a diagenetic process.

A four-step chemical extraction was applied to sediment cores from a heavily polluted area in Guanabara Bay, Rio de Janeiro. The results show that a pronounced change in the proportions of remobilisable copper occurred from the time previous to the local industrialisation (after 1955) to the present. A predominant fraction of the anthropogenic copper was remobilised after treatment with mild reagents. Extractions using EDTA solutions were able to recover up to 70% of the total copper in the sediments. Indications were found that estuarine particles (iron oxo-hydroxides, algae, etc.) are responsible for the transport of the anthropogenic copper to the sediments.

The main goal in the last few years in cardiac research has been to isolate cardiac potential stem cells from adult myocardium and to demonstrate their differentiation potential. We have previously demonstrated that c-Kit positive cardiac stem cells are able to organize themselves into a tissue-like cell mass. In this 3D mass, they can produce a high concentration of natural extracellular matrix, can create vessels, a capsule and, with the help of an Open-pore Polylactic Acid scaffold, many cells can organize an elementary myocardium. Drawing from this background, we decided to design and use poly-lactic scaffolds and the model of the athymic Nude-Foxn1(nu) mouse to evaluate the extent of the myogenic vs endothelial differentiation in vivo, and to evaluate the presence or the absence of a foreign body reaction.

The incidence of preterm delivery and the survival rate of preterm newborns are rising, due to the increased use of assisted reproductive technology associated with multiple gestations and improved technology in obstetrics and neonatology, which allow saving preterm infants at earlier gestational ages. As a consequence, the risk of developmental disabilities in preterm children is high, and clinical pictures need to be fully defined. Narrative review including articles regarding neurodevelopmental disorders published in the international medical literature and reported in Pub Med between the years 2000 and January 2010. Although survival rates of extremely low birth weight infants (ELBW) significantly increased during the last decade, the substantial stability of disability trends in this population was disappointing. Late-preterm infants, who account for about 75% of all preterm births and had not been considered at risk for adverse long-term neurodevelopmental outcomes in the past, are now reconsidered as more likely to develop such events, though their risk remains lower than in ELBW. The findings of the studies discussed in our article support the importance of early diagnosis in order to make decision about appropriate treatment of preterm infants.

A commonly used treatment for cerebral palsy in children is so-called 'conventional therapy', which includes physiotherapy or the neurodevelopmental approach. Although more intensive rehabilitative treatment is thought to be more effective than less intensive interventions, this assumption has not been proven. In this study we compared the efficacy of intensive versus nonintensive rehabilitative treatment in children with cerebral palsy. A meta-analysis of the studies published between January 1996 and July 2007 was performed.infants/children/adolescents (1-18 years old); randomized controlled trials using, as outcome measure, the Gross Motor Function Measure score.studies that included therapies not generally used in 'so-called' conventional treatment (i.e. constraint, taping). Treatment effects were combined using the weighted mean difference method. Fixed and random effect meta-analyses were carried out and results were compared. Heterogeneity was also assessed. Funnel plots were examined and the presence of small-study effects was tested. Intensive therapy tended to have a greater effect than nonintensive therapy (1.32; 95% confidence interval: 0.55-2.10). The effect of intensive treatment tended to be apparently stronger for children 2 years of age. Our meta-analysis shows that, in children with cerebral palsy, intensive conventional therapy may improve the functional motor outcome, but the effect size seems to be modest.

Pyrene metabolites in urine and micronucleus in haemocytes of crabs (Ucides cordatus) were tested as biomarkers of exposure to oil derived PAHs in mangrove sediments. The goal was to verify how well pyrene metabolites in urine represent levels of oil contamination in mangroves and whether the micronuclei assay indicates exposure. For this, bioassays were performed using crabs from clean and contaminated areas, and field studies were conducted in four mangroves. Results of the bioassay show that U. cordatus assimilates, metabolises, and excretes pyrene in urine as pyrene-1-glucoside, pyrene-sulphate and pyrene-conjugate. OH-pyrene-sulphate was the major metabolite produced/excreted over 120 h of observation by crabs from the clean mangrove. The production/excretion of pyrene-1-glucoside in this case increased linearly with time at a rate of 2.3 x 10(-10)mol L(-1)day(-1). The number of micronuclei in haemocytes also increased with the time after pyrene inoculation, indicating that exposure to pyrene triggers genotoxic and mutagenic response. In crabs from a heavily oil-contaminated mangrove pyrene-1-glucoside was the major metabolite, an indication that production/excretion of a certain metabolite varies depending on adaptation of the animal to the environment. A highly significant correlation was found between the concentration of pyrene metabolites in urine of field crabs expressed as OH-pyrene equivalents and the sum of 38 PAHs determined in hepatopancreas/sediments (r=0.825, n=23, p

An investigation was conducted in Ilha Grande and Sepetiba Bays aiming at identifying the nature of non-aromatic hydrocarbons (NAH) in surface sediments. NAH concentrations ranged from 2.5 µg g-1 to 193.8 µg g-1 of which the major fraction (53 to 93%) was composed by unresolved complex mixture (UMC). In most samples n-alkane distribution was dominated by compounds of odd carbon number showing maxima in nC29 and nC31. Mono-olefins were at low concentrations and the polyolefins including highly branched isoprenoids and squalene varied from 0.099 µg g-1 to 1.387 µg g-1 with lower values relative to NAH appearing in areas of strong terrestrial and anthropogenic influence. Hopanes between C27 and C33 were observed in all samples with the predominant configuration 17a(H),21b(H), characteristic of a petrogenic origin. Realizou-se uma investigação nas Baías de Ilha Grande e de Sepetiba sobre a natureza dos hidrocarbonetos não-aromáticos (NAH) em seus sedimentos. A mistura complexa não resolvida (UCM) constituiu de 50 a 90% da concentração dos NAH, que variou entre 2,5 µg g-1 e 193,8 µg g-1. Na maior parte das amostras a distribuição dos n-alcanos foi unimodal com predomínio de compostos de número ímpar de átomos de carbono e máximos em nC29 e nC31. Monolefinas ocorreram em baixas concentrações, enquanto as poliolefinas, incluindo isoprenoides ramificados e esqualeno, variaram entre 0,099 µg g-1 e 1,387 µg g-1, com os baixos valores relativos aos NAH surgindo em áreas de forte influência continental e antrópica. C27 - C33 hopanos foram encontrados em todas as amostras, assim como houve predominância da configuração 17a(H),21b(H), característica de origem petrogênica.

The concentration of black carbon (BC), as well as the relative contribution of BC to total organic carbon, was determined for the first time in sediments from Guanabara Bay. BC was quantified by a thermal oxidation method (CTO-375) and total organic carbon by dry oxidation. Sedimentary organic carbon showed a large range in concentrations (0.82 to 10.3%), but it was possible to define distinct regions of the Bay accordingly to variations in sediment grain size, location and magnitude of allochthonous and autochthonous sources of organic matter and hydrodynamic features. Low concentrations of BC were observed (0.03 to 0.31%, with a mean of 0.19 ± 0.07%, n = 25) when considering the large spectrum of possible sources on land and at sea. However, in some stations levels are sufficiently high as to influence the fate of pollutants of concern, such as PAH and dioxins. The space distribution of BC concentrations in Guanabara Bay cannot be fully understood at this stage since further information on contributions from various sources and on natural dispersion processes are required. As concentrações de black carbon (BC), assim como a contribuição relativa de BC para o total de carbono orgânico sedimentar, foram determinadas pela primeira vez na Baía de Guanabara. A quantificação de BC realizou-se por método térmico (CTO-375) e a de carbono orgânico por método de oxidação a seco. As concentrações de carbono orgânico apresentaram grande variabilidade entre as estações (0,82 a 10,3%), mas foi possível definir regiões distintas na Baía de acordo com parâmetros como granulometria do sedimento, localização e magnitude de fontes autóctonas e alóctonas de matéria orgânica e hidrodinamismo. As concentrações de BC foram inesperadamente baixas (0,03 a 0,31%, com média de 0,19 ± 0,07%, n = 25), levando-se em conta o largo espectro de fontes possíveis, tanto em terra como na água, para essas substâncias. No entanto, em algumas estações o BC estava presente em níveis que podem exercer influência sobre o destino de contaminantes prioritários, tais como HPA e dioxinas. Os resultados mostraram que a distribuição espacial das concentrações de BC na Baía de Guanabara é complexa e não pode ser completamente compreendida no estágio atual de conhecimento, sendo necessárias informações adicionais, tais como fontes de emissão de BC (p.ex., queima de biomassa e consumo de combustíveis) e processos de dispersão de partículas.

The Guanabara Bay in Rio de Janeiro has undergone profound alterations of its natural environmental conditions. Metal concentration increase in sediments has been reported to be among these alterations. Trace-metal contamination and availability were studied in sediments of 3 mangrove areas of the bay. Cd, Zn, Pb, Ni, Cu and Al concentrations were determined in segments of sediment cores, after treatment with 1 mol L-1 HCl and with concentrated HNO3. Fe and Mn were determined in the leach with HNO3. Concentrations were low in comparison to those reported for Guanabara Bay and Cd showed up to 90% recovery in the HCl extract. Sediments found to be oxic to suboxic showed AVS concentrations in range of 0.07 (bottom) to 18.79 mmol g-1(sub-surface) indicating heterogeneity and apparent disequilibrium. Fe and Mn oxides, carbonates and organic matter may be the most important phases controlling metal availability and distribution. A Baía de Guanabara no Rio de Janeiro tem sofrido profundas alterações ambientais. O aumento da concentração de metais-traço em seus sedimentos está entre as alterações mais relevantes. O objetivo deste trabalho foi verificar a contaminação por metais-traço e avaliar a disponibilidade em sedimentos de áreas de manguezais (Surui, Nova Orleans e Piedade). Concentrações de Cd, Zn, Pb, Ni, Cu e Al foram determinadas em segmentos de testemunhos após tratamento com 1 mol L-1 de HCl e com HNO3. Fe e Mn foram determinados na lixívia de HNO3 concentrado. As concentrações foram baixas em comparação com aquelas reportadas para a Baía de Guanabara e o Cd mostrou a mais alta recuperação em 1 mol L-1 HCl (90%). Apesar de oxidados ou subóxicos os sedimentos mostraram SAV na faixa de 0,07 to 18,79 mmol g-1 sugerindo heterogeneidade e desequilíbrio aparente. Óxidos de Fe, Mn, carbonatos e matéria orgânica são as fases que mais provavelmente controlam a biodisponibilidade dos metais.

This study is aimed at verifying the relevance of Ucides cordatus as a bioindicator of oil contamination and PAH bioavailability in mangrove sediments. For this, crabs and sediment cores were sampled from five mangroves, including an area suspected of contamination derived from an MF380 oil spillage, and analyzed for the 16 PAH in the USEPA priority list as well as for the five series of alkylated homologues. Concentrations in sediments varied from 35 μg kg−1 in the lower core layer of the control area to 33,000 μg kg−1 in the upper layer of the most contaminated area. Total PAH contents in crabs varied from 206 to 62,000 μg kg−1 and were closely correlated to that in sediments. In general, individual PAH profiles in both matrices were in good agreement. Phenanthrenes, however, were more predominant in crabs making up to 30–46% of the Total PAH. Accumulation factors found in the range of 0.7 to 35 were highly variable even after normalizing concentrations for organic carbon and lipid content. Survival in highly contaminated environment and reliable record of environmental contamination in the tissue provide evidence that U. cordatus is an excellent bioindicator for oil in mangroves. Keywords: Ucides cordatus, Crabs, PAH, Oil contamination, Sediments, Monitoring

In this work the re-fixation of mobilized copper (Cu) that was released from a deactivated pilot Cu ore dressing plant in the tropical rain forest at Southeastern Amazon (Carajás) was studied. Samples of top soils, decay leaf litter deposited on soils, roots and leaves of standing biomass were taken for the determination of Cu concentration in order to evaluate the distribution of it between different environmental compartments. In the sampling points near to the now extinct plant, total Cu concentrations in the soil reached an average value of 2140 microg g(-1) above the natural level of about 40 microg g(-1), being that bioavailable Cu estimated by DTPA method varied from 1.9 to 20.7% of this total. From the data was possible to calculate that the soil compartment is able to hold around 10 kg Cu/m(2) of ground. Roots of the standing biomass in that area hold around 17 g Cu/m(2), while the Cu content in leaves showed to be largely independent of the Cu level in the soil. Copper in the leaves was estimated as around 1g/m(2) of ground area. In turn, the decay leaf litter deposited on soil can hold about 1.6 g Cu/m(2). The terrestrial system surrounding the abandoned pilot plant demonstrated great buffer capacity to retain mobile Cu released by anthropogenic activities in the area.

Perna perna was collected from several sites along the coast of Rio de Janeiro and analysed for the content of copper, zinc, cadmium and chromium. In spite of the observed concentration variability in organisms pertaining to the same population, statistical evaluation allowed metal level differentiation among regions and sites as well as between males and females. Differences in metal contents did not confirm expectations based on source strength and existing data on water concentration. Foram coletados espécimes de mexilhões Perna perna de diversas estações ao longo da costa do Rio de Janeiro e analisados os conteúdos de cobre, zinco, cádmio e cromo. Apesar da grande variabilidade nos organismos pertencentes à mesma população, a avaliação estatística permitiu a diferenciação através de níveis de metal traço entre regiões e estações de coleta assim como entre machos e fêmeas. Diferenças nos conteúdos de metais não confirmam as espectativas baseadas em fontes de contaminação e dados existentes da concentração nas águas.

There are indications that the widespread use of organotin compounds (TBT and TPT) as antifoulings, as stabilizers in plastic and as pesticides, has severely affected several species of marine organisms. The most striking effect of TBT and TPT as hormonal disruptors is the development of male organs in females of gastropods, currently denominated imposex. This syndrome can lead to the sterilization and death of affected organisms. The present work gives an overview of the present state of knowledge on imposex occurrence and reports results of a survey conducted in Guanabara Bay, Rio de Janeiro and in several sites along the coast of Fortaleza, Ceará State. Different stages of imposex development were verified in this survey, however, the most prominent levels appeared associated to known spot sources of TBT and TPT. Existem evidências de que a utilização amplamente disseminada de compostos organoestânicos (TBT e TPT) como antiincrustantes, estabilizadores em plásticos e como pesticidas tenha afetado severamente diversas espécies de organismos marinhos. O mais característico efeito do TBT e do TPT como desreguladores endócrinos é o desenvolvimento de caracteres sexuais masculinos em fêmeas de gastrópodos, conhecido como imposex. Esta síndrome pode levar à esterelização e morte dos organismos afetados. O presente trabalho apresenta uma vista geral ao estado atual do conhecimento sobre a ocorrência do imposex, e reporta os resultados de um estudo conduzido na Baía de Guanabara, Rio de Janeiro, e ao longo da costa de Fortaleza, no Ceará. Diferentes estágios de desenvolvimento do imposex foram verificados neste estudo, os mais proeminentes parecendo associados às fontes pontuais locais conhecidas de TBT e TPT.

A critical evaluation is presented on the use of faecal sterols for the identification of sewage contamination in Guanabara Bay. Sediments were collected from 8 stations in the bay selected as representative of different contamination levels. GC/MS determination of faecal sterols gave: coprostanol, 335 - 40000 ng g-1; coprostanone, 112-4136 ng g-1; cholesterol, 1407-7800 ng g-1; cholestanol, 2011 - 10900 ng g-1 and cholestanone, 655-7954 ng g-1. The observed concentration is in accordance with the presence of known pollution sources, however, concentration ratios of different sterols species produced unclear results evidently influenced by primary production and microbial processes.

An electrochemical stripping procedure for ultra-trace measurements of adenine is described based on the adsorption of the adenine–copper complex on a static mercury drop electrode. Cyclic voltammetry was used to characterize the interfacial and redox behavior. Optimum experimental conditions were found when using a 0.005 M NaOH solution containing 0.4 ppm of copper, an accumulation potential of −0.30 V, a scan rate of 100 mV s −1 and a linear scan mode. There is a linear response to adenine concentration in the range of 0.1–1.0 ppb and the detection limit for 6 min accumulation time was of 4.0 ppt (3.0×10 −11 M). Proper conditions for measuring the adenine in presence of guanine, thymine and cytosine were also investigated. The method was applied for the determination of adenine in a sample of single-stranded calf thymus DNA.

The city of Rio de Janeiro, second majorindustrial and population center of Brazil, is locatedaround Guanabara Bay. The environmentalconditions of this tropical estuarine system has raisedgreat concem; nevertheless a systematic survey aboutpolynuclear aromatic hydrocarbons (P AH) has neverbeen carried ou1.Presently a study is being developedinvolving the investigation ofhydrocarbons in waters,sediments and biota. This work presents the firstresults related to polynuclear aromatic hydrocarbonsfound dissolved and dispersed in the waters of thebay.One of the major problems of the GuanabaraBay is the discharge of untreated domestic effluents,about 19m3 S-I, produced by a population of nearly8,000,000 inhabitants, enter this ecosystem daily.About 6,000 industries are established in this area.Also the natural resources of the bay are exploitedintensively, by both fishing and recreation activities.Guanabara Bay is an estuarine system wherehigh sedimentation rates are observed, of the order of1 to 2 cm year-l (Godoy et aI., 1991). The bay is alsoa very productive coastal ecosystem with rates ofprimary production of 460 mgC m-3 dail (Ponciano,1985).Guanabara Bay can be subdivided insections: the northeastem part is the most intact area,of 10wer population density, drained by relatively nonpolluted rivers and where remaining mangroves arepreserved; in the central part lies the navigationchannel, a frequently dredged area, with good watercirculation; the most impacted area is thenorthwestem section where refrnery plants from theoil industry are located and activities of oil storageand transfer are occurring. The two sections at theentrance of the Guanabara Bay are polluted mainly byharbor installations and shipyards.Ferreira (1995) concluded that the input ofpetroleum hydrocarbons to the bay amounts to 173 kgdai I from maritime transport, 902 kg day-l fromatmospheric input, and 17,005 kg day-l fTom urbanand industrial discharge. This last source accounts for84% ofthe hydrocarbon pollution discharge.The locations of the sampling stations areshown in Figure 1 with site descriptions. Thesestations were chosen as representative for the majoranthropogenic hydrocarbon input areas to the bay.

The adsorptive-catalytic voltammetry of Cr(VI) and total chromium using DTPA is optimized for application to estuarine waters with high content of dissolved organic substances. The sensitivity of the method, better than 2 nA nM-1 s'1, is adequate to the intended goal of speciation. However, the instability of Cr(VT) in the presence of organic material imposes restrictions to the use of this methodology in large scale surveys and monitoring activities.