Les sédiments de surface du Golfe du Morbihan et de la Baie de Quiberon ont été analysés afin d’évaluer les éléments traces métalliques (ETMs), leur comportement, les processus qui contrôlent leur distribution spatiale, leur spéciation, leur réactivité et leur biodisponibilité. Les potentielles sources métalliques ont été recherchées à partir de l’analyse des sédiments des ports à proximité et des sédiments du bassin versant. Les analyses ont été faites sur la fraction inférieure à 63 µm des sédiments collectés en Avril 2013. Les concentrations totales et la spéciation des ETMs ont été obtenues à partir des attaques totales et sélectives, respectivement. L’enrichissement en Zn, Cu, Cd et Pb a été mis en évidence dans les sédiments de surface du Golfe du Morbihan. De même, la labilité et la biodisponibilité du Pb ont été montrées dans les sédiments de la Baie de Quiberon. Le comportement des ETMs dans les sédiments de la côte morbihannaise est principalement contrôlé par le gradient terre/mer. Cependant, les ports et les rivières constituent des sources d’ETMs, principalement de Cu et Zn. / Surface sediments in the Gulf of Morbihan and the Bay of Quiberon were analyzed in order to characterize the trace metals elements, their behavior, the processes that control their spatial distribution, their speciation, reactivity and bioavailability. Potential sources of metals were looked for, based on the analysis of nearby harbors and river basin’s sediments. The analyses were done on the fraction below 63 µm of the sediments collected in April 2013. MTEs total concentration and speciation were obtained from total and selective attacks, respectively.The enrichment of Zn, Cu, Cd et Pb was identified in the surface sediments of the Gulf of Morbihan. Pb lability and bioavailability were shown in the sediments of the Bay of Quiberon. The MTEs behavior of the Morbihan’s coast is mostly controlled by the land-sea gradient. However, harbors and rivers form sources of ETMs, principally of Cu and Zn.

Rising carbon dioxide (CO2) concentrations in the atmosphere will increase the average pCO2 level in the world oceans, which will have a knock-on effect on the marine ecosystem. Coastal seagrass communities one of the most productive marine ecosystems are predicted to benefit from the increase in CO2 levels, but long-term effects of elevated CO2 on seagrass communities are less understood. Population reconstruction techniques was used to investigate the population dynamics of Cymodocea nodosa meadows, exposed to long term elevated CO2 at volcanic seeps off Greece and Italy. Effect of elevated CO2 was noticed on the growth, morphometry, density, biomass and age structure at CO2 seeps. Above to below ground biomass ratio of C. nodosa were higher at CO2 seeps than at reference sites. The plastochrome interval were similar at all CO2 seeps. The shoot age and shoot longevity of plants were lower at seeps than reference sites. The present recruitment (sampled year) of the seagrass were higher than long-term average recruitment of the communities near the seeps. Carbon to nitrogen ratios (%DW) of C. nodosa were higher in leaves at seeps. Annual leaf production was higher near the seeps. This study suggests increased production of C. nodosa under elevated CO2 levels, but other co-factors such as nutrients, trace metal toxicity must also be taken into consideration while predicting effects of future CO2 concentrations. Volcanic CO2 seeps are now being used as natural analogues for ocean acidification studies although these areas can be affected by trace element input and may alter ecosystem responses to gradient in carbonate chemistry. Here Fe and a range of trace elements (Cd, Co, Cu, Hg, Mn, Pb, Ni and Zn) were analysed from sediments and from the roots, rhizomes and leaves of seagrass at six CO2 seeps and reference sites off Greece and Italy. There were higher metal levels in sediment and seagrasses at all CO2 seeps than reference sites. Sediment Quality Guideline Quotient, a commonly used pollution index, indicated that some of the metals (Cd, Cu, Hg, Ni) were in high enough concentrations to have adverse biological effects, such as Cu at Ischia site and Hg at Vulcano. Higher accumulation of elements from sediments in roots and leaves at CO2 seeps were found from Bio Sediment Accumulation Factor index. There were higher levels of Cu, Fe, Mn and Zn in leaves and rhizomes for P. oceanica and higher levels of Cd, Co, Cu, Fe and Zn in C. nodosa compartments at CO2 seeps. Fe and Mn were found with positive correlation within sediment-roots and sediment-rhizomes, whereas Cd, Co and Pb were found with positive correlation in compartments of C. nodosa. In P. oceanica positive correlation were only observed for Cd within sediment-roots and plant compartments. Low pH and ocean acidification increased the concentration of elements at CO2 seeps than reference sites. Thus, caution is needed, when using volcanic seep systems as analogue for the effects of rising CO2, as metals can reach levels that are toxic to seagrass, masking any potential benefits of increased levels of carbon dioxide for seagrass productivity. Net community production (NCP) and community respiration (CR) were measured under air exposed and CO2 enriched conditions for intertidal Z. noltei meadows and unvegetated sediment communities during emersion in summer and winter seasons. Community production and respiration were measured in-situ using benthic chambers. CO2 flux under air and CO2 enriched conditions were measured over a series of short term incubations (30min) using an infra-red gas analyser. Incident photosynthetic active radiation (PAR) was recorded during the incubations covering the daily and seasonal variation. Linear regression model was used to test the effects of irradiance on net community production. NCP of Z. noltei community were higher under CO2 enriched conditions than air exposed conditions in both summer and winter seasons. There was no effect of CO2 on the CR rate of Z. noltei community in summer season. NCP of sediment community were higher in summer season and winter season under CO2 enriched conditions. Sediment CR rates were higher in winter than summer season. The light compensation point of Z. noltei and sediment community were lower in both seasons under CO2 enriched conditions. Seasonal budget of community production was higher in Z. noltei than sediment communities. A clear effect of PAR was noticed on the net community production of both communities. Higher PAR intensities resulted in higher NCP under CO2 enriched conditions for both communities. CO2 enrichment will have a positive effect on the intertidal communities during emersion.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2006. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-02-11T18:24:39Z No. of bitstreams: 1 2006_fabiana_barbosa.pdf: 1776412 bytes, checksum: 1983355c08ebff62770a80ecc0896046 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-11T21:35:03Z (GMT) No. of bitstreams: 1 2006_fabiana_barbosa.pdf: 1776412 bytes, checksum: 1983355c08ebff62770a80ecc0896046 (MD5) / Made available in DSpace on 2013-06-11T21:35:03Z (GMT). No. of bitstreams: 1 2006_fabiana_barbosa.pdf: 1776412 bytes, checksum: 1983355c08ebff62770a80ecc0896046 (MD5) Previous issue date: 2006 / Os estuários são áreas preferidas para a ocupação e urbanização devido a sua localização e importância sócio-econômica. Este tipo de ambiente é vulnerável ao lançamento de inúmeros compostos orgânicos e inorgânicos através de efluentes domésticos e industriais. O Canal de Acesso ao estuário da Lagoa dos Patos, sofre impactos diretos e indiretos, o que pode levar a uma possível deterioração ambiental. Monitoramentos no canal e suas áreas adjacentes são necessários, para a identificação do estado atual da qualidade ambiental principalmente nas áreas de influências diretas e indiretas das atividades portuárias. O objetivo do presente estudo é avaliar de forma espacial, sazonal e temporal as variações nas concentrações totais de metais traço (cádmio, cobre, chumbo e zinco) e de nutrientes dissolvidos (amônio, nitrato, nitrito e fosfato) em águas superficiais do Canal de Acesso (Canal do Rio Grande) ao estuário da Lagoa dos Patos, particularmente na área portuária da cidade do Rio Grande (Porto Novo, São José do Norte e Super porto). Neste estudo foram utilizados os dados obtidos de 5 relatórios técnicos realizados ao longo do eixo do canal, no período compreendido entre 1988 a 2004. A avaliação das concentrações dos nutrientes dissolvidos e metais traço indicou que ocorrem variações espaciais, sazonais e temporais, dependendo principalmente das condições metereológicas e hidrológicas da região, além das diversas influências antrópicas presentes no estuário da Lagoa dos Patos. De maneira geral, os nutrientes e os metais traço no Canal de Acesso apresentaram concentrações abaixo dos limites recomendados pela FEPAM e CONAMA. As concentrações de metais traço mostraram um decréscimo após o início das operações de dragagem de sedimentos no estuário, indicando a importância deste processo na remoção destes elementos do meio ambiente. / Estuaries are preferential areas for occupation and urbanization due its localization and socio-economic importance. This environment is vulnerable to the introduction of organic and inorganic compounds through domestic and industrials effluent. The access canal of the Patos Lagoon estuary, suffers from direct and indirect impacts, and can lead to a possible ambient deterioration. Monitoring studies in the canal and its adjacent regions is necessary to stablish the current state of the environment quality mainly in areas of direct and indirect influences of port activities. The aim of the present study is to evaluate spatially, seasonally and temporally variations of the total concentrations of trace metals (cadmium, copper, lead and zinc) and dissolved nutrients (ammonium, nitrate, nitrite and phosphate) in superficial waters of the Patos Lagoon estuary, particularly the region influenced by the Rio Grande Harbour (Porto Novo, São José do Norte and Superporto). Data between 1988 and 2004 were obtained from 5 technical reports. The assessment of dissolved nutrients and trace metal concentrations indicated that variations occur according the location, meteorological and hydrological conditions of a region, and antropic influences. Results showed that the nutrients and metals concentrations in the canal are below FEPAM and CONAMA recommended limits. Trace metals concentrations showed a decrease, after the beginning of sediment dredging operations in the estuary, showing the importance of this process in the removal of these elements from the environment.

A contaminação dos ecossistemas aquáticos por metais-traço demanda preocupação já que estes contaminantes podem exercer efeitos tóxicos sobre a biota e aumentar os custos para tratamento da água. Em geral, tais problemas de degradação são decorrentes de uma gestão de recursos hídricos deficiente. Tendo como área de estudo a represa Paiva Casto, reservatório integrante do Sistema Cantareira, maior sistema de abastecimento público da região metropolitana de São Paulo, este trabalho teve o intuito de: investigar o histórico da contaminação por metais-traço (Cd, Cr, Cu, Ni, Pb, Zn, Mn, Al) por meio da geocronologia por 210Pb e indicar um valor de referência para estes; identificar a heterogeneidade espacial destes contaminantes; analisar a biodisponibilidade e com base na possibilidade de adequar etapas do sistema de gestão de recursos hídricos europeu, a Diretiva Quadro da Água (DQA) discutir a qualidade química dos sedimentos da represa em estudo. Foram efetuadas duas coletas em campo, destinadas à avaliação do histórico da contaminação ambiental por metais-traço e à análise da biodisponibilidade por meio da técnica de sulfetos volatilizáveis por acidificação (SVA) e metais simultaneamente extraídos (MES). O histórico da contaminação por metais-traço abrangeu um período de 100 anos e indicou que os maiores impactos na região, em relação a estes contaminantes, ocorreu em período anterior ao início de operação da represa Paiva Castro, com exceção do Cu. Para o Cu, em sedimentos superficiais, os teores excederam até três vezes e meia o VR. Este resultado é provável consequência da aplicação de sulfato de cobre para o controle de florações de algas. Os dados para os VR divergiram daqueles estabelecidos para a crosta terrestre, porém foram semelhantes aos encontrados para a bacia do Alto Tietê, com exceção dos metais Cr e Pb. A análise de (SVA/MES) indicou que os metais não estavam biodisponíveis. Dentre as áreas amostradas, a região da barragem apresentou ao longo do tempo as maiores taxas de acumulação para metais-traço em contraposição à área de captação das águas para abastecimento público. Em relação a DQA, constatou-se que existe capacidade científica para avançar na incorporação de novos instrumentos na gestão, principalmente no Estado de São Paulo, entretanto, é preciso que haja sistemas de saneamento e monitoramento adequados e especialmente decisão política e rigor na aplicação destes novos instrumentos, caso contrário a incorporação da DQA é inviável. Aplicando algumas das normas da DQA na avaliação da qualidade química dos sedimentos da represa Paiva Castro constatou-se que a qualidade geral para este manancial é boa. Apesar disto é necessário que as políticas públicas sejam de fato aplicadas contra a degradação deste importante manancial, caso contrário a boa qualidade deste reservatório estará em risco / Contamination of aquatic ecosystems by trace metals demand concern since these contaminants may cause toxic effects on biota and increase costs for water treatment. In general, such degradation problems are due to a poor water management. A study was conducted at Paiva Castro reservoir, one of the reservoirs of the Cantareira System, largest public water supply system in the metropolitan region of São Paulo, this study aimed to: investigate the history of the accumulation of trace-metals (Cd, Cr, Cu, Ni, Pb, Zn, Mn, Al), through geochronology by 210Pb; establish background values (BV); analyze spatial heterogeneity; bioavailability and based on the possibility of adjusting some instruments of the European water resources management system, the Water Framework Directive (WFD), discuss the chemical quality of Paiva Castro\'s sediments. Two collections were performed, to assess the historical environmental contamination by trace-metals and to analyze the bioavailability using the technique of sulfides volatilizable by acidification (AVS) and simultaneously extracted metals (SEM). The history of contamination by trace- metals covered a period of 100 years and indicated that the greatest impacts in the region occurred in periods prior to the reservoir operation, with the exception of Cu. For Cu, in surface sediments, the levels exceeded three times and a half the BV. This result is probable consequence of copper sulphate application for controlling algal blooms. Data for BV were different from those found in the earth\'s crust, but similar to those found for the Alto Tietê basin, except for Cr and Pb metals. Analysis (AVS/ SEM) indicated that metals were not bioavailable. Among the sampled areas, the region of the dam, showed the highest rates of accumulation for trace- metals in contrast to the catchment area for public water supply. Regarding WFD, it was observed that there is scientific capacity to incorporate new instruments in the management, mainly in São Paulo, however, there must be adequate sanitation and monitoring systems and especially political decision and rigor in the application of these new tools, otherwise the incorporation of the WFD is unviable. Applying some of the WFD instruments in assessing the chemical quality of Paiva Castro\'s sediments, it was found that the quality of this ecosystem is good. Nevertheless, it is necessary that public policies are actually applied against the degradation of this important ecosystem; otherwise, reservoir\'s \'good quality\' will be at risk

Abstract The mineralogy and geochemistry of the fine and clay fractions of till in different moraine types and in different bedrock areas in northern Finland have been studied. A total of 250 till samples from 140 test pits were studied mineralogically and geochemically. X-ray diffraction, differential thermal and thermogravimetric analyses, transmission electron microscopy, X-ray fluorescence and atomic absorption spectrometry were used as analytical methods. In the clay fraction of till quartz, plagioclase, microcline and amphibole are the primary minerals occurring. The clay minerals proper include vermiculite, chlorite, illite, swelling-lattice vermiculite and mixed-layer clay minerals. Kaolinite occurs most abundantly in the clay fractions of till in the Kittilä, Jerisjärvi, Kaaresuvanto and Pulju areas. In the clay fraction of Kittilä and Jerisjärvi illite is dioctahedral type, but in their of other study areas both di- and trioctahedral types occur. Kaolinite and dioctahedral illite are evidence of the mixing of the weathered bedrock material into the till matrix. In the fine fraction of till most abundant minerals are primary minerals and clayminerals are in a minor role. In the clay fraction of till the content of primary minerals are at higher and secondary minerals are at lower level in the Granitic and Archaean gneiss areas than in the Greenstone Belt, Svecokarelian schists and gneiss and Granulite areas. Amphibole, microcline and plagioclase occur in very low amounts or are totally destroyed by chemical weathering in the clay fraction of the till in the Kittilä area. The mineral composition of fine and clay fractions in the tills of northern Inari gives an indication that there occur much more mafic volcanites than is known today. The mineralogical compositions of fine fraction of the tills correlates quite well with the underlying bedrock in all study areas, but clay fraction does not. Geochemical results are in accordance with the mineralogical composition of both fractions. In the fine fraction of the till Si, Ca and Na contents are higher than in the clay fraction. Clay fraction is enriched in Al, Fe, Mg, K and trace elements as compared to the fine fraction. Present study material points out that the distribution of chemical elements in the clay fraction of the till does not correlate with the composition of the underlying bedrock, but fine fraction does so with a few exceptions. The chemical composition of till in Kaaresuvanto and Inari does not fully correspond to the composition of the underlying bedrock as known today. In northern Inari and Kittilä the results give an indication that there are more mafic volcanites and/or sulphide mineralizations occurring in these areas than is known at the present time. The most important factors controlling the mineralogical and geochemical composition of the fine and clay fractions of the tills in northern Finland are the composition of the bedrock and the possible occurrence of an old weathering crust. The final grain size composition of the tills and consequently the quantitative proportions of the different minerals are often related to the last glacial quarrying and sorting processes; therefore the mineralogical composition of the tills is to a certain extent bound also to the respective moraine type.

The purpose of this study is to evaluate the relative advantages and disadvantages of two approaches for estimating oral bioaccessibility using a physiologically-based extraction technique (PBET): a simple gastric phase simulation and a two-phase gastrointestinal simulation. Bioaccessibility estimates of six metals prevalent in Canadian contaminated sites (zinc, lead, cadmium, copper, nickel, and chromium) were compared using the gastric phase simulation alone and the complete gastrointestinal simulation. Samples included vacuum dust samples from 33 homes, certified dust and soil reference materials, and a house dust control sample. Bioaccessibility measurements using the gastric phase simulation were greater than or equal to measurements obtained using the gastrointestinal simulation for the six studied metals. This research found that for the six studied metals, a simple simulation of the gastric phase provides the most conservative and cost-effective approach for estimating oral bioaccessibility of ingested metals.

Samples were taken from 72 high-rise apartment suites (6 suites in 12 individual high-rise towers) and 60 single-family houses located within the Greater Vancouver Regional District. The influence of the following factors on trace metal concentrations in 1-L first-flush drinking water samples and running hot water samples was investigated: building height, location, plumbing age, type of plumbing and type of building. Results of this survey show that with the exception of building height, all factors had a correlation with one or more of the trace metals investigated. The trace metals examined were lead, copper, iron and zinc. Lead was influenced primarily by building type, copper by plumbing age and type of plumbing and iron by location. Elevated lead levels were associated with high-rise samples. New copper plumbing systems resulted in high copper levels. Highest iron levels in the drinking water were measured in the East location. Zinc did not show a distinct correlation with any of the factors investigated. Brass faucets were the primary source of zinc in tap water. They also contributed substantially to the lead detected in the 1-L first-flush sample. Metal concentrations measured in high-rise and house samples were compared with U.S. Environmental Protection Agency's (USEPA) maximum contaminant levels (MCLs) and the proposed no-action level for lead1. In high-rise samples, the 0.01 mg/L "no-action" proposed for lead was exceeded in 43% of the samples and 62% of the samples exceeded the current 1.0 mg/L MCL standard for copper. In single-family house samples, these values were 1 Compliance with the proposed 0.01 mg/L no action limit for lead is based on a sample average. Individual samples may exceed this value and still be in compliance. 47% and 73%, respectively. The average lead concentration for all high-rise samples was 0.020 mg/L and 0.013 mg/L for house samples. Regulatory levels stated above would still be exceeded in 6% of the cases for lead and 9% of the cases for copper, even after prolonged flushing of the tap in a high-rise building. In all cases associated with single-family houses, flushing the cold water tap for 5 minutes was successful in achieving compliance levels. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

No description available.

Volcanoes are a key component of the Earth system, with volcanic activity reaching from deep in the Earth’s mantle and extending to interactions with volcanic gases and the atmosphere. Volatile trace metals degas from volcanic eruptions and at fumaroles, but their behaviour is poorly understood. I designed and built a benchtop fumarole, from which I degassed a silicate melt with trace metals, to simulate the volatilization and sublimation of trace metals from volcanic gases. I collected sublimates along a temperature gradient to examine the behaviour of the trace metals. The experimental sublimates were analysed for their chemical composition and phase identification. Lithium, Cu, As, Rb, Mo, Ag, Cd, Cs, W, Pt, Tl, Pb and Bi were found to be volatile and sublimed in elevated concentrations at various temperatures between 250-600°C. Compared to natural fumarole studies, similar volatile behaviour is seen for Cu, As, Ag and Tl. Variability between the experimental and natural fumarole sublimates is proposed to be from a lack of ligands in the experiments. Ligands can complex with trace metals, to transport and sublime mineralogical phases. Given the importance of ligands to metal complexation, I proceeded to examine the importance of chloride as a ligand in volatile transport and sublimation of trace metals. I degassed a silicate melt with trace metals and variable concentrations of Cl-, up to 2 wt% Cl-, in air. Sublimates produced from these experiments were analysed for mineralogical and chemical information. Raman spectroscopy and scanning electron microscopy helped to determine that silica polymorphs occur at all temperatures and that halite forms below 600°C. Additional phases, including hydrated phases transporting Mo, Cu and Pb also formed as sublimates. These hydrated phases are suggested to be hydrated post-experiment or are Cl--bearing analogues. The addition of Cl- to the experiments increases the concentration of Li, Rb, Cs, Ag, Cr, Cu, Mo and W in the sublimates compared to Cl-free experiments and Cl-bearing phases are likely hosts of volatile trace metals. Volcanic gases in nature do not have the oxygen fugacity of air and contain considerable S. To conduct sublimation experiments at various lower oxygen fugacities and with S as it is a redox sensitive ligand, I adapted my original benchtop fumarole design to a gas-mixing furnace, in which I degassed silicate melts containing S, Cl and trace metals. Substantial loss of S and Zn, Sn, As, Bi, Pb and Cd occurred from the starting material melt in the most reduced experiment at 4.6 log units below the FMQ buffer. This loss corresponded to increased concentrations of the same elements in the sublimates of the same experiment. These trace elements are likely hosted as sulfide minerals, as the fO2 conditions are in the sulfide stability field. This agrees with thermodynamic calculations that determine that sulfides should be stable in similar conditions to this experiment. Chlorides are sublimed in experiments from ~200-650°C and are likely subliming as a NaCl-KCl-FeCl3 solid solution. Halite is calculated to form at all temperatures in the experiments, based on modelling. These chlorides are probably hosting Cu, Cd, Bi, Li, Rb and Ag in the experiments. In nature, if these metals are in soluble salts, when leached they provide a source of metals to the environment where they are deposited. Overall, I demonstrated that trace metal behaviour in the sublimates from volcanic gases will be affected by available ligands and the oxygen fugacity of the melt and the gas. Chlorides are a likely phase to host trace metals and are ubiquitous in experiments, even with variable melt compositions, fO2 conditions and across a wide temperature range. / Graduate

Various criteria or lines of evidence have been used to identify ancient Maya marketplaces, including location near trade routes, artifactual evidence of trade, open space adjacent to transportation routes, proximity to public structures, low platforms and rock alignments to denote market spaces, and regular patterns in soil and floor chemical concentrations. Seibal and Mayapán were important economic Maya polities controlling the trade routes at the apex of their civilizations. The objectives of these studies were to apply geochemical and geospatial analyses of the soils and floors from public plazas and household patios, to discover the anthropogenic chemical residues of phosphorus (P) and heavy metals associated with the trade of foodstuffs and workshop items that may have been marketed there. Public access, causeways, reservoirs and a pattern of high P and metal concentrations are consistent with marketing of organic foodstuffs and workshop items within suspected marketplaces of each site. In contrast, geochemical patterns of the soils and floors of household structures are consistent with ceremonial and household activities.