Estudo de requalificação pedonal: o caso do centro urbano de Guimarães

A cidade que herdamos é produto de condicionalismos históricos, geralmente contraditórios, bem como resultado de circunstâncias económicas e políticas. Exceptuando as situações de catástrofe, o crescimento da cidade é resultado do aumento e população, de novos interesses de utilização dos solos e dos seus edifícios. A imagem dos edifícios é o resultado visível do processo urbano imposto pelas circunstâncias sociais. O maior interesse de uma cidade reside no seu espaço, sobretudo, se tivermos em mente que é nele que se realizam diariamente as diversas actividades sócio- económicas. De modo que, para falar da qualidade de vida de uma cidade é necessário começar por se analisar a qualidade dos seus espaços exteriores e elementos estruturais. O objectivo deste trabalho é o de caracterizar a qualidade pedonal urbana existente e de propor acções de qualificação do ambiente pedonal urbano. Deste modo, nesse trabalho ir-se-á desenvolver uma avaliação prévia das dimensões físicas, ambientais e de acessibilidade de um projecto de requalificação urbanística da praça do Toural, Alameda de São Dâmaso e Rua de Santo António em Guimarães, e propor acções de requalificação pedonal. Este trabalho inclui igualmente a descrição da proposta de intervenção com uma análise comparada do projecto face à situação existente

Qualidade pedonal urbana: o caso de Guimarães

As novas preocupações, com a qualidade de vida urbana, revelaram a necessidade de renovação das comunidades de vivência humana em espaço urbano, aumentado, deste modo, o interesse relativo ao ambiente pedonal. Este interesse vai para além do estudo das dimensões físicas dos espaços urbanos ou das suas características geométricas, procurando alargar a avaliação do ambiente encontrado pelo homem enquanto caminha pela cidade. Este trabalho tem como objectivo apresentar uma metodologia que permita avaliar se o desenho urbano responde de uma forma positiva na perspectiva da pessoa que caminha. Pretende-se esclarecer se as dimensões físicas e o ambiente pedonal correspondem às necessidades emocionais nas rotinas do caminhar. Deste modo, foi implementado um modelo de avaliação, na cidade de Guimarães - região noroeste de Portugal, procurando verificar se os espaços são bem dimensionados, seguros, confortáveis, e preparados para o tipo de uso previsto

Aplicação de SIG na avaliação da vulnerabilidade aquífera e cartografia da contaminação agrícola por pesticidas e nitratos na região do Ribatejo

As potencialidades dos Sistemas de Informação, ao nível do processamento e análise de dados georeferenciados e da criação de Sistemas de Apoio à Decisão, constituem modernas ferramentas de gestão e ordenamento do território com aplicação crescente em todas as áreas das Geociências e do Ambiente. No seguimento de vários estudos, realizados entre 1991 e 2000, sobre contaminação dos aquíferos por pesticidas e nitratos, na zona do Ribatejo, foram aplicadas metodologias apoiadas por suporte informático para avaliação da vulnerabilidade/susceptibilidade dos aquíferos à poluição e apresentados os respectivos mapas de qualidade ambiental relativamente aos teores de nitratos e alguns herbicidas, particularmente de alacloro, atrazina, metolacloro, metribuzina e simazina na água subterrânea. Os resultados obtidos constituem instrumentos fundamentais na gestão dos recursos hídricos subterrâneos e inclusivamente no estabelecimento de redes de monitorização adequadas em aquíferos vulneráveis

Ethoprophos fate on soil–water interface and effects on non-target terrestrial and aquatic biota under Mediterranean crop-based scenarios

The present study aimed to assess the environmental fate of the insecticide and nematicide ethoprophos in the soil–water interface following the pesticide application in simulated maize and potato crops under Mediterranean agricultural conditions, particularly of irrigation. Focus was given to the soil–water transfer pathways (leaching and runoff), to the pesticide transport in soil between pesticide application (crop row) and non-application areas (between crop rows), as well as to toxic effects of the various matrices on terrestrial and aquatic biota. A semi-field methodology mimicking a “worst-case” ethoprophos application (twice the recommended dosage for maize and potato crops: 100% concentration v/v) in agricultural field situations was used, in order to mimic a possible misuse by the farmer under realistic conditions. A rainfall was simulated under a slope of 20° for both crop-based scenarios. Soil and water samples were collected for the analysis of pesticide residues. Ecotoxicity of soil and aquatic samples was assessed by performing lethal and sublethal bioassays with organisms from different trophic levels: the collembolan Folsomia candida, the earthworm Eisenia andrei and the cladoceran Daphnia magna. Although the majority of ethoprophos sorbed to the soil application area, pesticide concentrations were detected in all water matrices illustrating pesticide transfer pathways of water contamination between environmental compartments. Leaching to groundwater proved to be an important transfer pathway of ethoprophos under both crop-based scenarios, as it resulted in high pesticide concentration in leachates from Maize (130 µg L−1) and Potato (630 µg L−1) crop scenarios, respectively. Ethoprophos application at the Potato crop scenario caused more toxic effects on terrestrial and aquatic biota than at the Maize scenario at the recommended dosage and lower concentrations. In both crop-based scenarios, ethoprophos moved with the irrigation water flow to the soil between the crop rows where no pesticide was applied, causing toxic effects on terrestrial organisms. The two simulated agricultural crop-based scenarios had the merit to illustrate the importance of transfer pathways of pesticides from soil to groundwater through leaching and from crop rows to the surrounding soil areas in a soil–water interface environment, which is representative for irrigated agricultural crops under Mediterranean conditions.This studywaspartlysponsoredbytheEuropeanFundfor Economic andRegionalDevelopment(FEDER)throughthePro- gram OperationalFactorsofCompetitiveness(COMPETE)and National FundsthroughthePortugueseFoundationofScience and Technology(Ph.D.granttoSaraLeitão – SFRH/BD/42306/2007, Ciência 2007 – POPH andQREN,andTerbAzineBiorem – PTDC/ AAC-AMB/111317/2009)

Effects of azoxystrobin, chlorothalonil and ethoprophos on the reproduction of three terrestrial invertebrates using a Mediterranean soil

The potential terrestrial toxicity of three pesticides, azoxystrobin, chlorothalonil, and ethoprophos was evaluated using reproduction ecotoxicological tests with different non-target species: the collembolan Folsomia candida, the earthworm Eisenia andrei, and the enchytraeid Enchytraeus crypticus. All reproduction tests were performed with natural soil from a Mediterranean agricultural area (with no pesticide residues) in order to improve the relevance of laboratory data to field conditions. Controls were performed with natural and standard artificial soil (OECD 10% OM). The fungicide azoxystrobin showed the highest toxicity to earthworms (EC50 = 42.0 mg a.i. kg−1 dw soil). Collembolans were the most sensitive taxa in terms of sublethal effects of chlorothalonil with an EC50 of 31.1 mg a.i. kg−1 dw soil followed by the earthworms with an EC50 of 40.9 mg a.i. kg−1 dw soil. The insecticide ethoprophos was the most toxic to collembolans affecting their reproduction with an EC50 of 0.027 mg a.i. kg−1 dw soil. Enchytraeids were generally the least sensitive of the three species tested for long-term effects. Earthworms were not always the most sensitive species, emphasizing the need to increase the number of mandatory assays with key non-target organisms in the environmental risk assessment of pesticidesinfo:eu-repo/semantics/publishedVersio

Cleanup of atrazine-contaminated soils: ecotoxicological study on the efficacy of a bioremediation tool with Pseudomonas sp. ADP

Purpose To mitigate the environmental effects of atrazine, one of the cleanup strategies available is based on the use of atrazine-degrading bacteria. This work aimed to evaluate the efficacy of a previously developed bioremediation tool for atrazine-contaminated soils (combining bioaugmentation with Pseudomonas sp. ADP, hereafter designated as P. ADP, and biostimulation with citrate) on both soil habitat and retention functions, by performing ecotoxicological tests with standard soil and aquatic species. Materials and methods Soil microcosms (incorporating earthworms, collembolans, and plants) were spiked with three doses of Atrazerba FL, an atrazine commercial formulation: the recommended dose (RD; 2 L/ha), 10×RD and 20×RD to simulate overuse/accidental spills scenarios. The experiment included two main groups of treatments: (1) microcosms sprayed solely with Atrazerba, i.e., nonbioremediated soils (NB) and (2) microcosms sprayed with both Atrazerba and the bioremediation tool (addition of P. ADP plus citrate), i.e., bioremediated soils (B). Control microcosms with no herbicide or P. ADP plus citrate addition were also set up. Besides soil chemical analysis, the following ecotoxicological endpoints were assessed to monitor bioremediation: plant biomass production, earthworm reproduction, microalgae growth (in eluates— collected 5 and 10 days after the bioremediation treatment— and leachates—collected on day seven), and cladoceran reproduction (in soil eluates). Results In NB soils, all Atrazerba doses induced a severe reduction in plant biomass production, and no effects were found for earthworm’s reproduction. Eluates and leachates obtained from the NB soils caused deleterious effects on both microalgae growth and cladoceran reproduction. Chemical analysis showed that atrazine degradation was faster in B soils than in the correspondent NB soils. Data from toxicity tests indicated that test organism performance was enhanced in B soils and respective eluates and leachates, compared to the NB samples. In fact, for soils contaminated with 10 and 20×RD Atrazerba doses, plant biomass production was significantly higher in the B soils than in the correspondent NB soils. Regarding the effects of soil bioremediation on the toxicity of soil eluates and leachates, for the soil contaminated with 10×RD of Atrazerba, over a 5-day treatment period, both microalgae growth and cladoceran reproduction were significantly higher in water extracts obtained from the B soils when compared with the NB extracts and also similar to the control. By the contrary, for the highest Atrazerba dose tested (20×RD), no significant differences were found on the toxicity of B and NB eluates toward both aquatic test organisms. However, for this same dose, after 7 days, microalgae growth was higher in B than in the NB leachates and similar to the control. Yet, after a longer bioremediation period of 10 days, eluates were also no longer toxic to both aquatic organisms. Discussion Based on atrazine soil chemical analysis, one can state that the addition of P. ADP plus citrate to the atrazine-contaminated soils was clearly effective in promoting atrazine biodegradation. In addition, ecotoxicological data support the efficacy of this cleanup tool. Indeed, results showed that the bioremediation treatment resulted in a relevant reduction on soil toxicity to a plant (approximately 100% and 72% of control, respectively, for 10× RD and 20×RD contaminated soils). In addition, 5 days of P. ADP activity were enough to annul atrazine toxic effects toward microalgae and cladocerans in eluates obtained from the soil contaminated with 10×RD of Atrazerba. For 20×RD, an effective detoxification of eluates was achieved only after a longer bioremediation period of 10 days. Conclusions The ecotoxicity tests proved not only the effective detoxification of bioremediated soils in 10 days but also the potential ability to concurrently reduce atrazine contamination of water compartments due to leaching and/ or run-off events, to levels that may no longer be hazardous to ecosystems. Due to the worldwide continued use of atrazine/triazine-based herbicidal formulations, further studies viewing the optimization of this cost-effective cleanup tool at larger scales (mesocosm and real field scenarios) and testing of other commercial formulations containing mixtures of atrazine/triazine and other active ingredient are still needed so that bioremediation can be used as a valuable tool to reduce herbicide toxicity in contaminated land.publishe

Interaction of contaminated sediment from a salt marsh with estuarine water: evaluation by leaching and ecotoxicity assays and salts from leachate evaporation

Purpose Wastes from a former Portuguese steel plant were deposited between 1961 and 2001 on the riverbank of a tributary of the Tagus River creating a landfill connected to the river, posing a potential contamination risk to the Tagus estuary ecosystem. This study aims to assess the transfer of chemical elements from contaminated sediments to the estuarine water from cycles of sediment leaching so as to evaluate the ecotoxicity of the leachates, and to analyze the solid phases crystallized from those leachates. Materials and methods Landfill sediment and estuarine water samples were collected during low tide. Sediment samples were analyzed for pH, electric conductivity (EC), C-org, NPK, and iron oxides. Leaching assays (four replicates) were done using estuarine water (200 cm(3)/replicate) and 1.5 kg of sediment per reactor. Each reactor was submitted to four leaching processes (0, 28, 49, and 77 days). The sediment was kept moist between leaching processes. Sediment (total (acid digestion) and available fraction (diluted organic acid extraction- Rhizo)) elemental concentrations were determined by inductively coupled plasma-instrumental neutron activation analysis (ICP/INAA). Leachates, and estuarine and sediment pore waters were analyzed for metals/metalloids by ICP/mass spectrometry (MS) and carbonates/sulfate/chloride by standard methodologies. Ecotoxicity assays were performed in leachates and estuarine and pore waters using Artemia franciscana and Brachionus plicatillis. Aliquots of the leachates were evaporated to complete dryness (23-25 degrees C) and crystals analyzed by X-ray powder diffraction (XRD). Results and discussion Sediment with pH=8 and high EC and Corg was contaminated with As, Cd, Cr, Cu, Pb, and Zn. The element concentrations in the available fraction of the sediment were low compared to the sediment total concentrations (<1 % for Rhizo extraction). The concentrations of potentially hazardous elements in the estuarine water were relatively low, except for Cd. Concentrations of hazardous elements in the leachates were very low. Calcium, K, Mg, Na, and chloride concentrations were high but did not vary significantly among the four leaching experiments. Total concentrations of carbonate were much higher in leachates than in estuarine water. Both estuarine water and leachates showed negligible toxicity. Crystals identified in the solids obtained from the leachates by evaporation were halite, anhydrite, epsomite, dolomite, and polyhalite. Conclusions The sediment showed the capacity to retain the majority of the potentially hazardous chemical elements. Remobilization of chemical elements from sediment by leaching was essentially negligible. The variation of total concentrations of Ca, carbonate, and sulfate in leachates indicates that the sediment contained reactive sulfides. Due to its composition, the sediment seems to be a dynamic system of pollution control, which should not be disturbed