Online health information - what the newspapers tell their readers: a systematic content analysis

Background: This study investigated the nature of newspaper reporting about online health information in the UK and US. Internet users frequently search for health information online, although the accuracy of the information retrieved varies greatly and can be misleading. Newspapers have the potential to influence public health behaviours, but information has been lacking in relation to how newspapers portray online health information to their readers.

Methods: The newspaper database Nexis (R) UK was searched for articles published from 2003 - 2012 relating to online health information. Systematic content analysis of articles published in the highest circulation newspapers in the UK and US was performed. A second researcher coded a 10% sample to establish inter-rater reliability of coding.

Results: In total, 161 newspaper articles were included in the analysis. Publication was most frequent in 2003, 2008 and 2009, which coincided with global threats to public health. UK broadsheet newspapers were significantly more likely to cover online health information than UK tabloid newspapers (p = 0.04) and only one article was identified in US tabloid newspapers. Articles most frequently appeared in health sections. Among the 79 articles that linked online health information to specific diseases or health topics, diabetes was the most frequently mentioned disease, cancer the commonest group of diseases and sexual health the most frequent health topic. Articles portrayed benefits of obtaining online health information more frequently than risks. Quotations from health professionals portrayed mixed opinions regarding public access to online health information. 108 (67.1%) articles directed readers to specific health-related web sites. 135 (83.9%) articles were rated as having balanced judgement and 76 (47.2%) were judged as having excellent quality reporting. No difference was found in the quality of reporting between UK and US articles.

Conclusions: Newspaper coverage of online health information was low during the 10-year period 2003 to 2012. Journalists tended to emphasise the benefits and understate the risks of online health information and the quality of reporting varied considerably. Newspapers directed readers to sources of online health information during global epidemics although, as most articles appeared in the health sections of broadsheet newspapers, coverage was limited to a relatively small readership.

Defining the content and delivery of an intervention to Change AdhereNce to treatment in BonchiEctasis (CAN-BE): a qualitative approach incorporating the Theoretical Domains Framework, behavioural change techniques and stakeholder expert panels

Background
Low patient adherence to treatment is associated with poorer health outcomes in bronchiectasis. We sought to use the Theoretical Domains Framework (TDF) (a framework derived from 33 psychological theories) and behavioural change techniques (BCTs) to define the content of an intervention to change patients’ adherence in bronchiectasis (Stage 1 and 2) and stakeholder expert panels to define its delivery (Stage 3).

Methods
We conducted semi-structured interviews with patients with bronchiectasis about barriers and motivators to adherence to treatment and focus groups or interviews with bronchiectasis healthcare professionals (HCPs) about their ability to change patients’ adherence to treatment. We coded these data to the 12 domain TDF to identify relevant domains for patients and HCPs (Stage 1). Three researchers independently mapped relevant domains for patients and HCPs to a list of 35 BCTs to identify two lists (patient and HCP) of potential BCTs for inclusion (Stage 2). We presented these lists to three expert panels (two with patients and one with HCPs/academics from across the UK). We asked panels who the intervention should target, who should deliver it, at what intensity, in what format and setting, and using which outcome measures (Stage 3).

Results
Eight TDF domains were perceived to influence patients’ and HCPs’ behaviours: Knowledge, Skills, Beliefs about capability, Beliefs about consequences, Motivation, Social influences, Behavioural regulation and Nature of behaviours (Stage 1). Twelve BCTs common to patients and HCPs were included in the intervention: Monitoring, Self-monitoring, Feedback, Action planning, Problem solving, Persuasive communication, Goal/target specified:behaviour/outcome, Information regarding behaviour/outcome, Role play, Social support and Cognitive restructuring (Stage 2). Participants thought that an individualised combination of these BCTs should be delivered to all patients, by a member of staff, over several one-to-one and/or group visits in secondary care. Efficacy should be measured using pulmonary exacerbations, hospital admissions and quality of life (Stage 3).

Conclusions
Twelve BCTs form the intervention content. An individualised selection from these 12 BCTs will be delivered to all patients over several face-to-face visits in secondary care. Future research should focus on developing physical materials to aid delivery of the intervention prior to feasibility and pilot testing. If effective, this intervention may improve adherence and health outcomes for those with bronchiectasis in the future.

The Role of Water Content and Paste Proportion on Physico-mechanical Properties of Alkali Activated Fly Ash–Ggbs Concrete

The growth of the construction industry worldwide poses a serious concern on the sustainability of the building material production chain, mainly due to the carbon emissions related to the production of Portland cement. On the other hand, valuable materials from waste streams, particularly from the metallurgical industry, are not used at their full potential. Alkali activated concrete (AAC) has emerged in the last years as a promising alternative to traditional Portland cement based concrete for some applications. However, despite showing remarkable strength and durability potential, its utilisation is not widespread, mainly due to the lack of broadly accepted standards for the selection of suitable mix recipes fulfilling design requirements, in particular workability, setting time and strength. In this paper, a contribution towards the design development of AAC synthetized from pulverised fuel ash (60%) and ground granulated blast furnace slag (40%) activated with a solution of sodium hydroxide and sodium silicate is proposed. Results from a first batch of mixes indicated that water content influences the setting time and that paste content is a key parameter for controlling strength development and workability. The investigation indicated that, for the given raw materials and activator compositions, a minimum water to solid (w/s) ratio of 0.37 was needed for an initial setting time of about 1 hour. Further work with paste content in the range of 30% to 33% determined the relationship between workability and strength development and w/s ratio and paste content. Strengths in the range of 50 - 60 MPa were achieved.

Content Validity in Landscape Valuation: A transdisciplinary approach to valuing the landscape of the peninsula of Sorrento, Italy.

This paper addresses the representation of landscape complexity in stated preferences research. It integrates landscape ecology and landscape economics and conducts the landscape analysis in a three-dimensional space to provide ecologically meaningful quantitative landscape indicators that are used as variables for the monetary valuation of landscape in a stated preferences study. Expected heterogeneity in taste intensity across respondents is addressed with a mixed logit model in Willingness to Pay space. The results suggest that the integration of landscape ecology metrics in a stated preferences model provides useful insights for valuing landscape and landscape changes

Do leaves of plants on phosphorus-impoverished soils contain high concentrations of phenolic defence compounds?

Prominent theories of plant defence have predicted that plants growing on nutrient-poor soils produce more phenolic defence compounds than those on richer soils. Only recently has the Protein Competition Model (PCM) of phenolic allocation suggested that N and P limitation could have different effects because the nutrients are involved in different cellular metabolic processes. 2. We extend the prediction of the PCM and hypothesize that N will have a greater influence on the production of phenolic defensive compounds than P availability, because N limitation reduces protein production and thus competition for phenylalanine, a precursor of many phenolic compounds. In contrast, P acts as a recyclable cofactor in these reactions, allowing protein and hence phenolic production to continue under low P conditions. 3. We test this hypothesis by comparing the foliar concentrations of phenolic compounds in (i) phenotypes of 21 species growing on P-rich alluvial terraces and P-depleted marine terraces in southern New Zealand, and (ii) 87 species growing under similar climates on comparatively P-rich soils in New Zealand vs. P-depleted soils in Tasmania. 4. Foliar P concentrations of plants from the marine terraces were about half those of plants from alluvial soils, and much lower in Tasmania than in New Zealand. However, foliar concentrations of N and phenolic compounds were similar across sites in both comparisons, supporting the hypothesis that N availability is a more important determinant of plant investment in phenolic defensive compounds than P availability. We found no indication that reduced soil P levels influenced plant concentrations of phenolic compounds. There was wide variation in the foliar N and P concentrations among species, and those with low foliar nutrient concentrations produced more phenolics (including condensed tannins). 5. Our study is the first trait comparison extending beyond standard leaf economics to include secondary metabolites related to defence in forest plants, and emphasizes that N and P have different influences on the production of phenolic defence compounds. © 2009 British Ecological Society.

Determination of the Mycotoxin Content in Distiller's Dried Grain with Solubles Using a Multianalyte UHPLC-MS/MS Method

There are more than 300 potential mycotoxins that can contaminate food and feed and cause adverse effects in humans and animals. The data on the co-occurrence of mycotoxins in novel animal feed materials, such as distiller's dried grain with solubles (DDGS), are limited. Thus, a UHPLC-MS/MS method for the quantitation of 77 mycotoxins and other fungal metabolites was used to analyze 169 DDGS samples produced from wheat, maize, and barley and 61 grain samples. All DDGS samples analyzed were contaminated with 13-34 different mycotoxins. Fumonisins were present in all 52 maize DDGS samples (81.0-6890 μg/kg for fumonisin B1), and deoxynivalenol was present in all 99 wheat DDGS samples (39.3-1120 μg/kg). A number of co-occurring mycotoxins were also identified. Due to the high co-occurrence of mycotoxins, routine screening of the animal feed ingredients is highly recommended to allow the highlighted risks to be effectively managed.

Effects of defined mixtures of persistent organic pollutants (POPs) on multiple cellular responses in the human hepatocarcinoma cell line, HepG2, using high content analysis screening

Persistent organic pollutants (POPs) are toxic substances, highly resistant to environmental degradation, which can bio-accumulate and have long-range atmospheric transport potential. Most studies focus on single compound effects, however as humans are exposed to several POPs simultaneously, investigating exposure effects of real life POP mixtures on human health is necessary. A defined mixture of POPs was used, where the compound concentration reflected its contribution to the levels seen in Scandinavian human serum (total mix). Several sub mixtures representing different classes of POP were also constructed. The perfluorinated (PFC) mixture contained six perfluorinated compounds, brominated (Br) mixture contained seven brominated compounds, chlorinated (Cl) mixture contained polychlorinated biphenyls and also p,p'-dichlorodiphenyldichloroethylene, hexachlorobenzene, three chlordanes, three hexachlorocyclohexanes and dieldrin. Human hepatocarcinoma (HepG2) cells were used for 2h and 48h exposures to the seven mixtures and analysis on a CellInsight™ NXT High Content Screening platform. Multiple cytotoxic endpoints were investigated: cell number, nuclear intensity and area, mitochondrial mass and membrane potential (MMP) and reactive oxygen species (ROS). Both the Br and Cl mixtures induced ROS production but did not lead to apoptosis. The PFC mixture induced the ROS production and likely induced cell apoptosis accompanied by the dissipation of MMP. Synergistic effects were evident for ROS induction when cells were exposed to the PFC+Br mixture. No significant effects were detected in the Br+Cl, PFC+Cl or total mixtures, which contain the same concentrations of chlorinated compounds as the Cl mixture plus additional compounds; highlighting the need for further exploration of POP mixtures in risk assessment.

Search filters: mapping the literature using a novel form of content analysis.

Background: Search filters are combinations of words and phrases designed to retrieve an optimal set of records on a particular topic (subject filters) or study design (methodological filters). Information specialists are increasingly turning to reusable filters to focus their searches. However, the extent of the academic literature on search filters is unknown. We provide a broad overview to the academic literature on search filters.
Objectives: To map the academic literature on search filters from 2004 to 2015 using a novel form of content analysis.
Methods: We conducted a comprehensive search for literature between 2004 and 2015 across eight databases using a subjectively derived search strategy. We identified key words from titles, grouped them into categories, and examined their frequency and co-occurrences.
Results: The majority of records were housed in Embase (n = 178) and MEDLINE (n = 154). Over the last decade, both databases appeared to exhibit a bimodal distribution with the number of publications on search filters rising until 2006, before dipping in 2007, and steadily increasing until 2012. Few articles appeared in social science databases over the same time frame (e.g. Social Services Abstracts, n = 3).
Unsurprisingly, the term ‘search’ appeared in most titles, and quite often, was used as a noun adjunct for the word 'filter' and ‘strategy’. Across the papers, the purpose of searches as a means of 'identifying' information and gathering ‘evidence’ from 'databases' emerged quite strongly. Other terms relating to the methodological assessment of search filters, such as precision and validation, also appeared albeit less frequently.
Conclusions: Our findings show surprising commonality across the papers with regard to the literature on search filters. Much of the literature seems to be focused on developing search filters to identify and retrieve information, as opposed to testing or validating such filters. Furthermore, the literature is mostly housed in health-related databases, namely MEDLINE, CINAHL, and Embase, implying that it is medically driven. Relatively few papers focus on the use of search filters in the social sciences.

Reframing the Favela, Remapping the City: Territorial Embeddedness and (Trans)locality in “Framing Content” on Brazilian Favela Blogs

In recent years, the internet has become a key site for the portrayal of Rio de Janeiro’s favelas. This article examines blogging by favela residents and argues that digital culture constitutes a vital, and as yet not systematically explored, arena of research on the representation of Rio de Janeiro and its favelas. Based on ethnographically inspired research carried out in 2009–2010, this article examines two examples of blog ‘framing content’ (a sidebar and a static page) encountered during fieldwork, which functioned to establish a concrete link between the posts on the blogs in question, their authors, and a named favela, even when the posts were not explicitly about that favela. At the same time, the framing content also made visible, and affirmed, the translocal connections between that favela, other favelas, and the city as a whole. These illustrative examples from a wider study show how favela bloggers are engaged in resignifying and remapping the relationships between different empirical scales of locality (and associated identities) in Rio de Janeiro, demonstrating the contribution an interdisciplinary approach to the digital texts and practices of favela residents can make to an understanding of the contemporary city and its representational conundrums, from the perspective of ‘ordinary practitioners’.

Volumetric Carbon Content Calculations: A Geostatistical and Compositional Approach

This study applies spatial statistical techniques including cokriging to integrate airborne geophysical (radiometric) data with ground-based measurements of peat depth and soil organic carbon (SOC) to monitor change in peat cover for carbon stock calculations. The research is part of the EU funded Tellus Border project and is supported by the INTERREG IVA development programme of the European Regional Development Fund, which is managed by the Special EU Programmes Body (SEUPB). The premise is that saturated peat attenuates the radiometric signal from underlying soils and rocks. Contemporaneous ground-based measurements were collected to corroborate mapped estimates and develop a statistical model for volumetric carbon content (VCC) to 0.5 metres. Field measurements included ground penetrating radar, gamma ray spectrometry and a soil sampling methodology which measured bulk density and soil moisture to determine VCC. One aim of the study was to explore whether airborne radiometric survey data can be used to establish VCC across a region. To account for the footprint of airborne radiometric data, five cores were obtained at each soil sampling location: one at the centre of the ground radiometric equivalent sample location and one at each of the four corners 20 metres apart. This soil sampling strategy replicated the methodology deployed for the Tellus Border geochemistry survey. Two key issues will be discussed from this work. The first addresses the integration of different sampling supports for airborne and ground measured data and the second discusses the compositional nature of the VOC data.

Effect of storage on physical-chemical properties and phenolics of sweet cherry from São Julião region.

Effect of storage on physical-chemical properties and phenolics of sweet cherry from São Julião region. A.C. Agulheiro-Santos1, F. Vieira1, D. Gonzalez2, M. Lozano2, V. Palma1, A.E. Rato1 1Universidade de Évora. Instituto de Ciências Agrárias e Ambientais Mediterrânica (ICAAM). 7000 Évora, Portugal. 2Centro de Investigaciones Científicas y Tecnológicas de Extremadura (CICYTEX). Ctra. San Vicente. Finca Santa Engracia. 06071 Badajoz, Spain. Worldwide the consumption of fruit and vegetables is increasing due to the dietary guidelines recommended by nutritionist. Because of their high content on phenols, vitamins, mineral and antioxidants, berry fruits are consumed not only in fresh forms but also as processed and derivative products such as juices, yogurts, jellies and dried fruits. As a high consumed red fruit, sweet cherry has been the focus on some studies, mainly regarding bioactive compounds content. “Sweetheart” cherries from São Julião region (Alentejo, Portugal) from two different production campaigns were kept in different storage conditions in order to evaluate both the environmental and storage effect on some physical-chemical properties and phenolics. Cold conditions - Cold (1 ºC, 95% RH) and modified atmosphere - MA (1 ºC, 95% RH with micro-perforated bags of Pplus®, Sidlaw Packaging, Bristol, UK) were tested. In order to establish the appropriate storage conditions, individual phenolic acids and physical-chemical properties were analysed during two consecutive years. Results show a general decrease on phenolic compounds content between cherries from both years. It is also observed that MA conditions do not affect significantly both phenolics and physical-chemical parameters when compared with Cold conditions. Additionally, it is observed similar behaviour on Cold and MA sweet cherries regarding its pH, total soluble solids content (TSS), titratable acidity (TA) and colour and individual phenols during storage time. Concluding, these results show, as expected, changes between cultivars which may be correlated with the environmental conditions on different years. Keywords: sweet cherry, postharvest, phenols, physical-chemical, storage conditions.

Relação do aroma e da espuma dos vinhos espumantes com o potencial enológico das uvas e dos vinhos

Os espumantes produzidos segundo o método Champanhês são obtidos após uma segunda fermentação em garrafa. Quando o vinho é vertido no copo, o CO2 produzido é libertado, sendo a espuma formada o resultado da sua interacção com os constituintes do vinho. A quantidade e a estabilidade da espuma do vinho espumante estão relacionadas com a sua composição química. Para além da espuma, o aroma é também um parâmetro importante de qualidade na apreciação geral de um vinho espumante. O aroma de um vinho espumante provém do contributo das uvas assim como do processo fermentativo. Dependendo do estado de maturação da uva, o contributo dos compostos voláteis para o aroma é diferente. Em virtude da vindima para os vinhos espumantes ser realizada antes da vindima para os vinhos maduros, dependendo da variedade, as uvas poderão não ser colhidas na expressão máxima do seu aroma, podendo verificar-se uma perda significativa do seu potencial varietal volátil. O objectivo desta dissertação é relacionar o aroma e a espuma dos vinhos espumantes com o potencial enológico das uvas e dos vinhos. Para isso, foi estudada a composição volátil das duas castas principais da Bairrada, a casta branca Fernão-Pires (FP) e a casta tinta Baga (BG), sendo estas duas das castas usadas para a produção de espumante. Para estudar a composição volátil das uvas durante a maturação, com vista a avaliar este efeito na expressão máxima de compostos voláteis, foi optimizada para este propósito a metodologia de microextracção em fase sólida em espaço de cabeça (HS-SPME). As uvas foram colhidas semanalmente, em duas vinhas, do pintor à pós-maturidade sendo posteriormente analisadas pela metodologia de HS-SPME seguida de cromatografia de gás acoplada à espectrometria de massa com quadrupolo (GC–qMS). No caso das uvas BG, observou-se um aumento acentuado na expressão máxima de compostos voláteis próximo da maturidade da uva determinada pelo teor em açúcar e acidez titulável, mantendo-se constante durante a pós-maturidade. Na determinação do perfil volátil das uvas ao longo da maturação foram identificados 66 compostos varietais nas uvas provenientes de uma vinha (Pedralvites) e 45 da outra vinha (Colégio). Em ambas as vinhas foram identificados 23 sesquiterpenóides, 13 monoterpenóides, 6 norisoprenóides, 2 álcoois aromáticos e 1 diterpenóide. Os sesquiterpenóides, devido à sua abundância em número e em área cromatográfica, podem ser considerados marcadores da casta BG. As uvas FP apresentaram um comportamento diferente do das uvas BG, sendo a expressão máxima de compostos voláteis expressa durante um curto período de tempo (1 semana), que coincide com a maturidade da uva. Depois de atingido este pico, observa-se uma diminuição drástica logo na semana seguinte. Este comportamento foi observado em ambas as vinhas, onde foram identificados 20 compostos voláteis varietais e 5 pré-fermentativos (álcoois e aldeídos em C6). Estes resultados mostram que quando estas castas são colhidas precocemente (1 semana antes da maturidade) para a produção de espumante, é observada uma redução significativa do potencial volátil que é expresso na maturidade. Para a análise da composição volátil dos vinhos espumantes foi optimizada uma metodologia de microextracção que permite usar uma maior quantidade de fase estacionária, a extracção sorptiva em barra de agitação (SBSE). O método foi optimizado usando 10 padrões de compostos voláteis representativos das principais famílias químicas presentes no vinho, nomeadamente, ésteres, monoterpenóides, sesquiterpenóides, norisoprenóides em C13 e álcoois. O método proposto apresenta uma boa linearidade (r2 > 0,982) e a reprodutibilidade varia entre 8,9 e 17,8%. Os limites de detecção para a maioria dos compostos é bastante baixo, entre 0,05 e 9,09 μg L-1. O método foi aplicado para a análise da composição volátil dos vinhos espumantes. Dentro dos vinhos espumantes analisados, foi estudada a influência da casta, do tipo de solo e do estado de maturação das uvas na sua composição volátil. A casta FP pode dar origem a vinhos com maior potencial de aroma do que a casta BG. Relativamente à avaliação dos diferentes estados de maturação, verificou-se que as uvas da maturidade e as da colheita tardia (uma semana depois da maturidade) deram origem aos vinhos com maior quantidade de compostos voláteis. Para os três tipos de solo estudados (arenoso, argiloso e argilo-calcário), o vinho obtido a partir de uvas colhidas no solo argilo-calcário foi o que mostrou a maior concentração de compostos voláteis varietais. A espuma destes vinhos espumantes foi também avaliada quanto à sua quantidade máxima (HM) e tempo de estabilidade (TS). O vinho espumante que apresentou um maior TS foi o vinho produzido a partir da casta FP proveniente de uma colheita tardia e solo argiloso. Os vinhos provenientes dos solos arenosos e argilo-calcários são os que apresentaram valores mais baixos de TS. Com vista a avaliar quais os conjuntos de moléculas do vinho que estão relacionados com as propriedades da espuma e possíveis sinergismos entre eles, para cada vinho espumante foi separada a fracção hidrofóbica de baixo peso molecular (MeLMW), a fracção de elevado peso molecular (HMW) e duas fracções de peso molecular intermédio (AqIMW e MeIMW). As propriedades da espuma dos vinhos modelo, reconstituídos com estas fracções e suas misturas, foram avaliadas. A combinação da fracção HMW com a MeLMW aumentou o TS 2,7 vezes quando comparado com o observado para a fracção HMW isoladamente, produzindo um efeito sinergético. Este aumento do TS ainda foi maior quando se combinou a fracção HMW com as subfracções obtidas a partir da fracção MeLMW, principalmente para as fracções menos apolares. A subfracção hidrofóbica menos apolar foi caracterizada por espectrometria de massa de ionização por electrospray (ESI-MS/MS) tendo sido identificada uma série de oligómeros de polietileno glicol e um potencial composto tensioactivo, o 8-hidroxi-tridecanoato de dietilenoglicolglicerilacetato. A fracção MeLMW foi também isolada da espuma do vinho espumante e caracterizada por ESI-MS/MS, permitindo identificar vários compostos potenciais tensioactivos, nomeadamente, dois monoacilgliceróis e quatro derivados de ácidos gordos com gliceriletilenoglicol. Estes resultados confirmam que estes compostos relacionados com a estabilidade da espuma existem em maior número na espuma do que no vinho. O vinho foi ainda fraccionado em 12 grupos de moléculas: 3 fracções de manoproteínas, 3 de arabinogalactanas, 3 de misturas de polissacarídeos, proteínas e compostos fenólicos e 3 fracções de peso molecular intermédio e baixo, compostas por uma mistura de hidratos de carbono, peptídeos e compostos fenólicos. Foram usados vinhos modelo reconstituídos com cada uma das fracções isoladas na concentração em que estas se encontraram no vinho. Foram também efectuados ensaios com soluções modelo dez vezes mais concentradas e com misturas de algumas das fracções. Todas as soluções formadas foram avaliadas quanto às propriedades da espuma. O aumento da concentração para dez vezes faz com que a solução contendo a fracção rica em manoproteínas (MP1) aumente para mais do dobro a HM e 7,4 vezes mais o TS. A combinação entre a fracção MP1 e a MeLMW produziu um aumento significativo nos parâmetros de HM e TS. A combinação da fracção HMW (manoproteínas com baixo teor em proteína) com a MeLMW (tensioactivos derivados de ácidos gordos com gliceriletilenoglicol) contém os compostos chave de um vinho espumante para se obter uma maior quantidade e estabilidade da espuma.

Matéria húmica de sapal: variações estruturais e complexação com o cobre

No presente trabalho foram estudadas as variações na composição, estrutura e comportamento das substâncias húmicas sedimentares (SHS), promovidas pela presença de duas espécies de plantas da família Chenopodiacea, presentes nos sapais da Ria de Aveiro: a Halimione portulacoides e a Arthrocnemum fruticosum. Para além das variações espaciais horizontais, foram investigadas as variações ao longo de um perfil de profundidades. Desta forma, para além da camada superficial (0-10 cm) de sedimentos com diferentes espécies de plantas e sem plantas, também foram investigadas camadas de sedimentos intermédia (20-25 cm) e profunda (45-50 cm). Para a extracção das SHS recorreu-se a uma pequena modificação do método proposto pela International Humic Substances Society (IHSS) para extracção e purificação de substâncias húmicas de solos. As SH extraídas foram caracterizadas através dos métodos espectroscópicos de absorção no ultravioleta visível, de fluorescência molecular síncrona, de absorção no infravermelho com transformadas de Fourier (FTIR) e de RMN 13C em estado sólido. Estas técnicas de caracterização foram complementadas pela análise elementar e termogravimetria. Em algumas amostras, foram ainda determinados o conteúdo em alguns metais por ICP-AES e o conteúdo funcional ácido por titulações potenciométricas. Após exaustiva caracterização das amostras de AH, procedeu-se ao estudo da sua capacidade de complexação com o cobre, recorrendo a titulações monitorizadas por fluorescência molecular síncrona. Os resultados revelaram que a colonização de sedimentos por plantas vasculares superiores conduz a uma alteração profunda no ambiente sedimentar e que esta é reflectida na diagénese das substâncias húmicas sedimentares, tendo-se observado variações a uma pequena escala espacial. O estudo deste tipo de variações nunca tinha sido efectuado em trabalhos anteriores. Nos ácidos fúlvicos detectaram-se diferenças na composição e estrutura das amostras correspondentes às camadas superiores de sedimentos, reflectindo a presença de diferentes colonizações vegetais. Relativamente aos ácidos húmicos, foi possível classificá-los em dois tipos distintos. Os AH do tipo I correspondem aos sedimentos superficiais e intermédios dos locais com plantas. Neste tipo de AH verificou-se uma incorporação de polissacarídeos e estruturas peptídicas, em estados de humificação pouco desenvolvidos. Os AH do tipo II correspondem aos sedimentos mais profundos de todos os locais e aos intermédios do local sem plantas e caracterizam-se por um maior grau de humificação e polimerização, um maior conteúdo aromático e de estruturas conjugadas e um maior conteúdo de grupos carboxílicos. Essas diferenças estruturais conduzem a diferentes comportamentos ácido/base e de complexação com o cobre. Assim, os AH do tipo I, que apresentam sinais espectroscópicos mais baixos associados a grupos carboxílicos e fenólicos, têm menor conteúdo de grupos funcionais ácidos e menor capacidade de complexação com o cobre quando se consideram ligandos característicos de unidades aromáticas conjugadas. Relativamente aos valores de log K dos complexos de AHS com o cobre, as amostras representativas da camada superficial dos sedimentos com plantas apresentaram valores superiores aos das restantes amostras de AH estudadas, cujos valores de log K são similares entre si. Atendendo aos resultados de análise elementar e espectroscópica, este facto pode estar associado à presença de compostos de azoto não peptídicos. Quanto a outros ligandos para o cobre, nomeadamente os representativos de estruturas peptídicas contendo o aminoácido triptofano e estruturas aromáticas simples, não foi possível obter resultados conclusivos. Dado que os ácidos húmicos do tipo I demonstraram um maior conteúdo peptídico e menor conteúdo aromático, o estudo destes ligandos torna-se importante para compreender melhor o efeito da presença de plantas nos sedimentos de sapal sobre o comportamento dos ácidos húmicos sedimentares como ligandos para o cobre. Refere-se ainda que foram detectadas certas especificidades na variação das características do sedimento e das substâncias húmicas com a profundidade nos diferentes locais estudados que não podem ser explicadas meramente com a presença de material vegetal oriundo de diferentes espécies de plantas, requerendo um conhecimento mais aprofundado das comunidades bentónicas e do ambiente físico-químico do sedimento.