Modelling nitrogen and phosphorus loads in a Mediterranean river catchment (La Tordera, NE Spain)

Human activities have resulted in increased nutrient levels in many rivers all over Europe. Sustainable management of river basins demands an assessment of the causes and consequences of human alteration of nutrient flows, together with an evaluation of management options. In the context of an integrated and interdisciplinary environmental assessment (IEA) of nutrient flows, we present and discuss the application of the nutrient emission model MONERIS (MOdelling Nutrient Emissions into River Systems) to the Catalan river basin, La Tordera (north-east Spain), for the period 1996–2002. After a successful calibration and verification process (Nash-Sutcliffe efficiencies E=0.85 for phosphorus and E=0.86 for nitrogen), the application of the model MONERIS proved to be useful in estimating nutrient loads. Crucial for model calibration, in-stream retention was estimated to be about 50 % of nutrient emissions on an annual basis. Through this process, we identified the importance of point sources for phosphorus emissions (about 94% for 1996–2002), and diffuse sources, especially inputs via groundwater, for nitrogen emissions (about 31% for 1996–2002). Despite hurdles related to model structure, observed loads, and input data encountered during the modelling process, MONERIS provided a good representation of the major interannual and spatial patterns in nutrient emissions. An analysis of the model uncertainty and sensitivity to input data indicates that the model MONERIS, even in data-starved Mediterranean catchments, may be profitably used by water managers for evaluating quantitative nutrient emission scenarios for the purpose of managing river basins. As an example of scenario modelling, an analysis of the changes in nutrient emissions through two different future scenarios allowed the identification of a set of relevant measures to reduce nutrient loads.

Is Microtox R toxicity related to potentially harmful algae proliferation in Mediterranean salt marshes?

Mediterranean salt marshes are ecosystems that are highly influenced by sea changes and freshwater inputs from runoff. In these ecosystems, toxic and non-toxic algae blooms often produce large and unpredictable biomasses of phytoplankton. The Microtox R test has been described as a successful, quick method for detecting toxicity in various phytoplankton taxa. Ourstudy sought to test the efficiency of Microtox R in detecting toxic HAB in Mediterranean salt marshes. The results showed that the Microtox R test was able to detect toxic substances in the particulate matter of several lagoons in the Empordà salt marshes. This Microtox R toxicity coincided with periods when potentially harmful cyanobacteria, dinoflagellates andhaptophytes had a high biomass. The results suggest that potentially harmful phytoplankton cannot be ruled out as a source of Microtox R

Active sulphide mine tailings impoundments as sources of contaminated drainage: controlling factors, methods of characterisation and geochemical constraints for mitigation

Low quality mine drainage from tailings facilities persists as one of the most significant global environmental concerns related to sulphide mining. Due to the large variation in geological and environmental conditions at mine sites, universal approaches to the management of mine drainage are not always applicable. Instead, site-specific knowledge of the geochemical behaviour of waste materials is required for the design and closure of the facilities. In this thesis, tailings-derived water contamination and factors causing the pollution were investigated in two coeval active sulphide mine sites in Finland: the Hitura Ni mine and the Luikonlahti Cu-Zn-Co-Ni mine and talc processing plant. A hydrogeochemical study was performed to characterise the tailingsderived water pollution at Hitura. Geochemical changes in the Hitura tailings were evaluated with a detailed mineralogical and geochemical investigation (solid-phase speciation, acid mine drainage potential, pore water chemistry) and using a spatial assessment to identify the mechanisms of water contamination. A similar spatial investigation, applying selective extractions, was carried out in the Luikonlahti tailings area for comparative purposes (Hitura low-sulphide tailings vs. Luikonlahti sulphide-rich tailings). At both sites, hydrogeochemistry of tailings seepage waters was further characterised to examine the net results of the processes observed within the impoundments and to identify constraints for water treatment. At Luikonlahti, annual and seasonal variation in effluent quality was evaluated based on a four-year monitoring period. Observations pertinent to future assessment and mine drainage prevention from existing and future tailings facilities were presented based on the results. A combination of hydrogeochemical approaches provided a means to delineate the tailings-derived neutral mine drainage at Hitura. Tailings effluents with elevated Ni, SO₄ ^2- and Fe content had dispersed to the surrounding aquifer through a levelled-out esker and underneath the seepage collection ditches. In future mines, this could be avoided with additional basal liners in tailings impoundments where the permeability of the underlying Quaternary deposits is inadequate, and with sufficiently deep ditches. Based on the studies, extensive sulphide oxidation with subsequent metal release may already initiate during active tailings disposal. The intensity and onset of oxidation depended on e.g. the Fe sulphide content of the tailings, water saturation level, and time of exposure of fresh sulphide grains. Continuous disposal decreased sulphide weathering in the surface of low-sulphide tailings, but oxidation initiated if they were left uncovered after disposal ceased. In the sulphide-rich tailings, delayed burial of the unsaturated tailings had resulted in thick oxidized layers, despite the continuous operation. Sulphide weathering and contaminant release occurred also in the border zones. Based on the results, the prevention of sulphide oxidation should already be considered in the planning of tailings disposal, taking into account the border zones. Moreover, even lowsulphide tailings should be covered without delay after active disposal ceases. The quality of tailings effluents showed wide variation within a single impoundment and between the two different types of tailings facilities assessed. The affecting factors included source materials, the intensity of weathering of tailings and embankment materials along the seepage flow path, inputs from the process waters, the water retention time in tailings, and climatic seasonality. In addition, modifications to the tailings impoundment may markedly change the effluent quality. The wide variation in the tailings effluent quality poses challenges for treatment design. The final decision on water management requires quantification of the spatial and seasonal fluctuation at the site, taking into account changes resulting from the eventual closure of the impoundment. Overall, comprehensive hydrogeochemical mapping was deemed essential in the identification of critical contaminants and their sources at mine sites. Mineralogical analysis, selective extractions, and pore water analysis were a good combination of methods for studying the weathering of tailings and in evaluating metal mobility from the facilities. Selective extractions with visual observations and pH measurements of tailings solids were, nevertheless, adequate in describing the spatial distribution of sulphide oxidation in tailings impoundments. Seepage water chemistry provided additional data on geochemical processes in tailings and was necessary for defining constraints for water treatment.

Nucleus accumbens is involved in human action monitoring: evidence from invasive electrophysiological recordings

The Nucleus accumbens (Nacc) has been proposed to act as a limbic-motor interface. Here, using invasive intraoperative recordings in an awake patient suffering from obsessive-compulsive disease (OCD), we demonstrate that its activity is modulated by the quality of performance of the subject in a choice reaction time task designed to tap action monitoring processes. Action monitoring, that is, error detection and correction, is thought to be supported by a system involving the dopaminergic midbrain, the basal ganglia, and the medial prefrontal cortex. In surface electrophysiological recordings, action monitoring is indexed by an error-related negativity (ERN) appearing time-locked to the erroneous responses and emanating from the medial frontal cortex. In preoperative scalp recordings the patient's ERN was found to be signifi cantly increased compared to a large (n = 83) normal sample, suggesting enhanced action monitoring processes. Intraoperatively, error-related modulations were obtained from the Nacc but not from a site 5 mm above. Importantly, crosscorrelation analysis showed that error-related activity in the Nacc preceded surface activity by 40 ms. We propose that the Nacc is involved in action monitoring, possibly by using error signals from the dopaminergic midbrain to adjust the relative impact of limbic and prefrontal inputs on frontal control systems in order to optimize goal-directed behavior.

Fatores que governam a especiação do cobre em ambientes aquáticos urbanos: evidências da contribuição de sulfetos solúveis

Copper speciation and behavior in different rivers located in the city of Curitiba were evaluated in this work. Sampling locations were selected to cover different levels of urbanization regarding their anthropogenic occupation and land use. Results showed that in highly-developed areas, both organic matter and dissolved sulfides were able to control copper speciation. Dissolved sulfide species were the major complexing agent in areas where dissolved oxygen levels are low. Finally, it was demonstrated that in urban areas anthropogenic factors such as sewage inputs and occupation of the drainage basin are the key aspects controlling copper dynamics and speciation in river waters.

The materiality of the immaterial. Services sectors and CO2 emissions in Uruguay

This paper analyzes the carbon dioxide emissions of the services sectors subsystem of Uruguay in 2004. Services, with the exception of transport, are often considered intangible because of their low level of direct emissions. However, the provision of services requires inputs produced by other sectors, including several highly materialintensive sectors. Through input–output analysis we investigate the relationship between the services subsystem and the rest of the economy as regards carbon dioxide emissions. This approach allows us to study the importance of the set of services branches as a unit in the economic structure as well as to analyze in detail the relationship between the branches. The results depict that services’ direct emissions are the main component, as a consequence of transport-related sectors. However, the pollution that the services subsystem makes the rest of the economy produce is very significant, and it is almost all explained by non-transport-related sectors. This analysis is useful for determining the sectors in which mitigation policies are more effective, and whether they would be better tackled through technical improvements and better practices or through demand policies.

Control de 6 respiròmetres i anàlisi de les dades

L’aplicació de tècniques respiromètriques és de recent innovació dins l’estudi dels tractaments d’aigües residuals. Aquest conjunt de tècniques ens permeten analitzar dos processos importants dins una planta de tractament biològic: el creixement de la biomassa i el consum del substrat. Això fa que siguin una eina amb gran potencial en l’avaluació dels sistemes de tractament biològic d’aigües residuals. L’objectiu principal d’aquest treball es la realització d’una aplicació capaç de controlar el funcionament de 6 respiròmetres, gestionant el procés del mostreig de les respirometries i l’anàlisi de les dades obtingudes, per obtenir el substrat ràpidament biodegradable (Ss) per a mostres d’aigua residual, i la taxa màxima de creixement específic per a mostres de compost. L’aplicació s’ha desenvolupat sobre l’entorn Microsoft Access, on s’integren la base de dades amb les mostres i els resultats de les respirometries, i els formularis de control que ens permeten gestionar i controlar els processos de mostreig i anàlisi. L’aplicació es comunica amb els sensors i actuadors dels respiròmetres a través del control ActiveX, ADS-OCX, subministrat per TwinCAT, que ens permet capturar les lectures dels sensors i controlar el funcionament dels actuadors. Aquests elements estan connectats a mòduls descentralitzats d’entrades i sortides, comunicats mitjançant el bus Ethernet amb el PC-Industrial, on s’executa l’aplicació. Un cop finalitzada l’aplicació, aquesta controla correctament el mostreig de les respirometries, registrant les lectures de les sondes a la base de dades i controlant l’activació de les vàlvules del respiròmetre. Partint de les mostres obtingudes, o de respirometries externes, importades des de Microsoft Excel, s’ha comprovat el correcte funcionament en el càlcul del substrat ràpidament biodegradable (Ss) i la taxa màxima de creixement específic. Amb l’aplicació desenvolupada, s’ha comprovat el funcionament i les possibilitats que ens ofereix TwinCAT alhora de controlar mòduls d’entrades i sortides, així com la seva comunicació amb aplicacions com Microsoft Access. Això pot afavorir a la utilització d’aquest tipus de tecnologia, per aplicacions futures.

Disseny i muntatge d'un mòdul d'entrades digitals per comunicació modbus

Actualment l’exigència i la competitivitat del mercat, obliguen les industries a modernitzar-se i automatitzar tots els seus processos productius. En aquests processos les dades i paràmetres de control són dades fonamentals a verificar. Amb aquest treball final de carrera, es pretén realitzar un mòdul d’entrades digitals, per tal de gestionar les dades rebudes d’un procés automatitzat. L’objectiu d’aquest TFC ha estat dissenyar un mòdul d’entrades digitals capaç de gestionar dades de qualsevol tipus de procés automatitzat i transmetre-les a un mestremitjançant un bus de comunicació Modbus. El projecte però, s’ha centrat en el cas específic d’un procés automatitzat per al tractament de la fusta. El desenvolupament d’aquest sistema, comprèn el disseny del circuit, la realització de la placa, el software de lectura de dades i la implementació del protocol Modbus. Tot el mòdul d’entrades està controlat per un microcontrolador PIC 18F4520. El disseny és un sistema multiplataforma per tal d’adaptar-se a qualsevol procés automàtic i algunes de les seves característiques més rellevants són: entrades aïllades multitensió, control de fugues, sortides a relé, i memòria externa de dades, entre altres. Com a conclusions cal dir que s’han assolit els objectius proposats amb èxit. S’ha aconseguit un disseny robust, fiable, polivalent i altament competitiu en el mercat. A nivell acadèmic, s’han ampliat els coneixements en el camp del disseny i de la programació.

Comprovador semiautomàtic per a automatisme de control de portes

L’objectiu d’aquest projecte és el de dissenyar un comprovador semiautomàtic per a un model d’automatisme que controla l’obertura i el tancament d’una porta. Aquest automatisme requereix d’una verificació de qualitat abans de ser introduït al mercat. La seva comprovació manual és lenta. L’objectiu principal del comprovador, és el de reduir aquest temps de test en almenys un 50% i fer més fàcil la detecció dels errors. El comprovador consta d’un suport per a l’automatisme que transmet els seus punts crítics a una placa de control. Conté un microcontrolador PIC16F887 que gestiona totes les entrades i sortides provinents de l’automatisme. També controla una pantalla LCD de 16x2 caràcters, que mostra els passos a seguir del test i si hi ha algun error. Es fa el disseny d’aquesta placa des de el hardware fins al software. Els resultats del projecte són satisfactoris, ja que compleix els objectius marcats i és un sistema que s’utilitza en l’empresa on es fabriquen aquests automatismes de control de portes.

Sistema d'adquisició de temperatures de 2 canals via R.F.

Poder mesurar i enregistrar diferents tipus de magnituds com pressió, força, temperatura etc. s’ha convertit en una necessitat per moltes aplicacions actuals. Aquestes magnituds poden tenir procedències molt diverses, tals com l’entorn, o poden ser generades per sistemes mecànics, elèctrics, etc. Per tal de poder adquirir aquestes magnituds, s’utilitzen els sistemes d’adquisició de dades. Aquests sistemes, prenen mostres analògiques del món real, i les transformen en dades digitals que poden ser manipulades per un sistema electrònic. Pràcticament qualsevol magnitud es pot mesurar utilitzant el sensor adient. Una magnitud molt utilitzada en sistemes d’adquisició de dades, és la temperatura. Els sistemes d’adquisició de temperatures estan molt generalitzats, i podem trobar-los com a sistemes, on l’objectiu és mostrar les dades adquirides, o podem trobar-los formant part de sistemes de control, aportant uns inputs necessaris per el seu correcte funcionament, garantir-ne l’estabilitat, seguretat etc. Aquest projecte, promogut per l’empresa Elausa, s’encarregarà d’adquirir, el senyal d’entrada de 2 Termoparells. Aquests mesuraran temperatures de circuits electrònics, que es trobaran dintre la càmera climàtica de Elausa, sotmesos a diferents condicions de temperatura, per tal de rebre l’homologació del circuit. El sistema haurà de poder mostrar les dades adquirides en temps real, i emmagatzemar-les en un PC que estarà ubicat en una oficina, situada a uns 30 m de distància de la sala on es farà el test. El sistema constarà d’un circuit electrònic que adquirirà, i condicionarà el senyal de sortida dels termoparells, per adaptar-lo a la tensió d’entrada d’un convertidor analògic digital, del microcontrolador integrat en aquesta placa. Seguidament aquesta informació, s’enviarà a través d’un mòdul transmissor de radiofreqüència, cap al PC on es visualitzaran les dades adquirides. Els objectius plantejats són els següents: - Dissenyar el circuit electrònic d’adquisició i condicionament del senyal. - Dissenyar, fabricar i muntar el circuit imprès de la placa d’adquisició. - Realitzar el programa de control del microcontrolador. - Realitzar el programa per presentar i desar les dades en un PC. - El sistema ha d’adquirir 2 temperatures, a través de Termoparells amb un rang d’entrada de -40ºC a +240ºC - S’ha de transmetre les dades via R.F. Els resultats del projecte han estat satisfactoris i s’han complert els objectius plantejats.

Aproveitamento sustentável de biomassa e de recursos naturais na inovação química

Increased production of biomass is currently the only immediately accessible alternative for large-scale carbon sequestration and it can produce large amounts of food, fuel and raw materials for the chemical industry that can in turn growingly replace oil as a source of organic building blocks and also of hydrogen and sulfur. Development of processes for biomass and abundant minerals transformation into chemical raw materials should now benefit from large inputs from nanotechnologies, biotechnologies, information and micro-reactor technologies. Success in R&D&Innovation along this line can yield new products and processes needed to perform desirable functions within a sustainable development paradigm.

Hidrocarbonetos e esterois como indicadores de fontes e destino de matéria orgânica em sedimentos da Baía de Sepetiba, Rio de Janeiro

The inputs of organic matter derived from natural and anthropogenic sources to Sepetiba Bay were investigated by using aliphatic hydrocarbons and sterols in superficial sediments. Concentrations ranged from 0.26 to 2.65 μg g-1, <0.01 to 17.41 μg g-1 and 0.77 and 9.24 μg g-1 for n-alkanes, UCM (unresolved complex mixture) and total sterols, respectively. The selected markers and ratios among individual compounds showed the major contribution of terrestrial sources to the total pool of sedimentary organic matter in the bay, but the accumulation of autochthonous organic matter increased with distance from the shoreline. The input of petroleum hydrocarbons and sewage (coprostanol in the range 0.01 to 0.43 μg g-1) were also detected, especially in the more urbanized regions of the bay, but at lower levels of contamination when compared to estuaries in other Brazilian coastal regions.

Fontes e distribuição de matéria orgânica sedimentar no complexo estuarino-lagunar de Mundaú-Manguaba/AL, utilizando esterois e alcoóis como indicadores

The origin of the sedimentary organic matter in the Mundaú-Manguaba estuarine system was evaluated through the distribution and composition of sterols, alcohols and ancillary data. The muddy sediments of the lagoons are enriched in organic matter, derived from a mixture of autochthonous and allochthonous inputs. Mundaú exhibited moderate contamination by sewage, with coprostanol concentration as high as 4.4 µg g-1. The channels are characterized by sand and organic matter-poor sediments. The sediments from some rivers in the drainage basin accumulated organic matter derived only from terrestrial vegetation. Stanol/sterol ratios evidenced the preferential diagenesis of the autochthonous fraction of organic matter.

Fluxos de nutrientes associados às descargas de água subterrânea para a Lagoa Mangueira (Rio Grande do Sul, Brasil)

This study assesses the importance of groundwater discharge to dissolved nutrient levels in Mangueira Lagoon. A transect of an irrigation canal in the margin of Lagoon demonstrated a strong geochemical gradient due to high groundwater inputs in this area. Using 222Rn as a quantitative groundwater tracer, we observed that the flux of dissolved inorganic nitrogen (DIN), silicate and phosphate (1178 and 1977; 26190 and 35652; 167 and 188 mol d-1 for winter and summer, respectively) can continually supply/sustain primary production. The irrigation canals act as an artificial underground tributary and represent a new source of nutrients to coastal lagoons.

Corais como organismos biomonitores: aplicação, pré-tratamento e determinação de elementos majoritários e minoritários

Corals incorporate major and trace elements in their tissues and skeletons, acting as good proxies for contaminant inputs over time. This incorporation occurs by a variety of mechanisms and depends on the bioavailability of elements. Corals are very susceptible to metal contamination during sample collection. As such, pre-treatment procedures need to include a decontamination step. The high Na and Ca concentrations in the matrix make the determination of trace metals an analytical challenge. The present paper reviews all the information published on coral sample pretreatments, metal determinations in corals, and also discusses the use of coral to monitor metal contamination.