Lucía Emilia Iglesias  Carlos Saumell  Federica Sagüés  Juan Manuel Sallovitz  Adrián Luis Lifschitz 《Journal of environmental science and health. Part. B》2018,53(1):42-48

The aim of this work was to evaluate the fate of ivermectin (IVM) at two concentrations in cattle feces and its movement to the nearby soil and plants. Feces were spiked with IVM at two levels: 3000 ng g^?1 (high group, HG) and 300 ng g^?1 (low group, LG). Artificial dung pats were prepared and deposited in an experimental field area. Feces and underlying soil were sampled up to 60 days post-deposition (dpd). As an additional analysis, grasses growing around the pats were sampled at 30 and 60 dpd. Ivermectin concentrations in all matrices were determined by HPLC. Mean IVM fecal concentrations were in the range between 3901.9 ng g^?1 and 2419.2 ng g^?1 (high group) and 375.3 ng g^?1 and 177.49 ng g^?1 (low group). Mean times for 50% and 90% dissipation were 88.23 and 293.03 days (HG) and 39.1 and 129.9 days (LG). Soil concentrations ranged from 26.1 ng g^?1 to 71.1 ng g^?1 (HG) and 3.4 to 5.9 ng g^?1 (LG); in plants, concentrations were between 71.4 and 380.8 ng g^?1 and 5.40 and 51.8 ng g^?1 in HG and LG, respectively. These results confirm that IVM moves from feces to the underlying soil as well as to nearby plants. The potential risk of detrimental effects on soil organisms and the impact on herbivorous animals should be further evaluated.  相似文献   

    

Emily V. Buckner  Daniel L. Hernández  Jameal F. Samhouri 《Ambio》2018,47(4):493-503

Conservation efforts tend to focus on the direct impacts humans have on their surrounding environment; however there are also many ways in which people indirectly affect ecosystems. Recent research on ecological subsidies—the transfer of energy and nutrients from one ecosystem to another—has highlighted the importance of nutrient exchange for maintaining productivity and diversity at a landscape scale, while also pointing toward the fragility of ecotones and vulnerability of subsidies to human activities. We review the recent literature on landscape connectivity and ecosystem subsidies from aquatic systems to terrestrial systems. Based on this review, we propose a conceptual model of how human activities may alter or eliminate the flow of energy and nutrients between ecosystems by influencing the delivery of subsidies along the pathway of transfer. To demonstrate the utility of this conceptual model, we discuss it in the context of case studies of subsidies derived from salmon, marine mammals, sea turtles, sea birds, and shoreline debris. Subsidy restoration may require a different set of actions from simply reversing the pathway of degradation. We suggest that effective restoration and conservation efforts will require a multifaceted approach, targeting many steps along the subsidy transfer pathway, to address these issues.  相似文献   

    

E. Gramsch  V. Papapostolou  F. Reyes  Y. Vásquez  M. Castillo  P. Oyola 《Journal of the Air & Waste Management Association (1995)》2018,68(4):329-346

Bioethanol for use in vehicles is becoming a substantial part of global energy infrastructure because it is renewable and some emissions are reduced. Carbon monoxide (CO) emissions and total hydrocarbons (THC) are reduced, but there is still controversy regarding emissions of nitrogen oxides (NO_x), aldehydes, and ethanol; this may be a concern because all these compounds are precursors of ozone and secondary organic aerosol (SOA). The amount of emissions depends on the ethanol content, but it also may depend on the engine quality and ethanol origin. Thus, a photochemical chamber was used to study secondary gas and aerosol formation from two flex-fueled vehicles using different ethanol blends in gasoline. One vehicle and the fuel used were made in the United States, and the others were made in Brazil. Primary emissions of THC, CO, carbon dioxide (CO₂), and nonmethane hydrocarbons (NMHC) from both vehicles decreased as the amount of ethanol in gasoline increased. NO_x emissions in the U.S. and Brazilian cars decreased with ethanol content. However, emissions of THC, CO, and NO_x from the Brazilian car were markedly higher than those from the U.S. car, showing high variability between vehicle technologies. In the Brazilian car, formation of secondary nitrogen dioxide (NO₂) and ozone (O₃) was lower for higher ethanol content in the fuel. In the U.S. car, NO₂ and O₃ had a small increase. Secondary particle (particulate matter [PM]) formation in the chamber decreased for both vehicles as the fraction of ethanol in fuel increased, consistent with previous studies. Secondary to primary PM ratios for pure gasoline is 11, also consistent with previous studies. In addition, the time required to form secondary PM is longer for higher ethanol blends. These results indicate that using higher ethanol blends may have a positive impact on air quality.

Implications: The use of bioethanol can significantly reduce petroleum use and greenhouse gas emissions worldwide. Given the extent of its use, it is important to understand its effect on urban pollution. There is a controversy on whether there is a reduction or increase in PM emission when using ethanol blends. Primary emissions of THC, CO, CO₂, NO_x, and NMHC for both cars decreased as the fraction of ethanol in gasoline increased. Using a photochemical chamber, the authors have found a decrease in the formation of secondary particles and the time required to form secondary PM is longer when using higher ethanol blends.  相似文献   

    

Cláudia Ribeiro  Ana Rita Ribeiro  Maria Elizabeth Tiritan 《Journal of environmental science and health. Part. B》2016,51(3):143-153

Persistent organic pollutants (POPs) are widespread compounds, such as organohalogenated compounds, polycyclic aromatic hydrocarbons (PAHs) and pesticides, which can be found in all types of environmental compartments. Their presence in the aquatic environment is a worldwide problem, with emphasis on sediments which act as depository and consequently as a source of hydrophobic, recalcitrant and harmful compounds. Besides, these pollutants might affect the reproduction and mortality of living organisms, diverging in their potential to bioaccumulate in tissues. The present paper aims to review the occurrence of POPs in sediments and biota from the coastal, estuarine and river areas of Portugal. The list of the studied compounds comprises organohalogenated compounds, PAHs, organometallic compounds, pesticides, sterols, fatty acids and pharmaceutical compounds. The contamination of sediments by various pollutants is presented, such as PAHs up to 7,350 ng g^?1 found in Sado estuary and polychlorinated biphenyls up to 62.2 ng g^?1 in the case of sediments collected in Ria de Aveiro. The occurrence of these persistent toxic substances in sediments demonstrates aquatic contamination from agricultural, industrial and urban discharges and the concern about the potential risks to aquatic organisms, wildlife and humans. In fact, several classes of POPs have also been found in biota, such as polychlorinated biphenyls up to 810.9 ng g^?1 in sentinel fish from the Douro River estuary and pesticides in bivalves from the Sado River estuary. The importance of further systematic research on sediments and biota is here highlighted to compare the contamination of these two reservoirs; to assess their spatial and temporal variation; and to determine other classes of POPs that were not investigated yet (e.g., industrial compounds, estrogens and many classes of pharmaceuticals).  相似文献   

    

Bortolotto  Ieda Maria  Hiane  Priscila Aiko  Ishii  Iria Hiromi  de Souza  Paulo Robson  Campos  Raquel Pires  Juraci Bastos Gomes  Rosane  Farias  Cariolando da Silva  Leme  Flávia Maria  de Oliveira Arruda  Rosani do Carmo  de Lima Corrêa da Costa  Liana Baptista  Damasceno-Junior  Geraldo Alves 《Regional Environmental Change》2017,17(5):1329-1341

Regional Environmental Change - The conservation and use of wild food plants should include local people in the decision-making process, and many countries have done so. However, interacting with...  相似文献   

    

González-Marín  Rosa María  Moreno-Casasola  Patricia  Castro-Luna  Alejandro Antonio  Castillo  Alicia 《Regional Environmental Change》2017,17(5):1343-1354

Regional Environmental Change - Wetlands play important roles that benefit social-ecological systems. They are threatened by climate change and human activities, i.e., raising livestock and...  相似文献   

    

Stephen Samuel  Leila Álvarez Garcia 《International Journal of Sustainable Engineering》2014,7(4):293-306

The interest in obtaining alternative fuels from waste sources and at the same time diminishing the impact of waste disposal has drawn attention to scrap tyres' carbon recovery. In order to thermally degrade used tyre rubber, a laboratory pyrolysis system was developed in this work. The installation devised focused on the production of liquid pyrolysates, where shredded rubber was supplied as the feedstock and nitrogen used as the carrier gas to provide an oxygen-free atmosphere. The variables affecting the performance of the process were investigated, including target temperature, heating rate and total residence time. Characterization of the volatile matter released was conducted by means of mass spectrometry to determine the composition of products, and particulate matter analysis to ascertain the aerosol content in the gas stream. The reproducibility of experiments, the influence of the temperature and time, and differences between the vapours before condensation and the exhaust gases are discussed. This work identified that the larger hydrocarbon fragments condense to constitute the oils, whereas the lighter molecules remain as non-condensable gases. This work also identified that the total number of nano-scale particles carried by the exhaust stream varies with temperature; significant changes in the composition of products and particle content were reported at approximately 400°C. The high number of nano-scale solid particulate matter present in the exhaust gases suggests that a thorough treatment for that stream would be required to avoid human health hazards.  相似文献   

    

Flores  Federico M.  Undabeytia  Tomas  Morillo  Esmeralda  Torres Sánchez  Rosa M. 《Environmental science and pollution research international》2017,24(16):14463-14476

Environmental Science and Pollution Research - Pyrimethanil (2-aniline-4, 6-dimethylpyrimidine, PRM) is used in fruit packing plants to control fungal infections and diseases. The effluents greatly...  相似文献   

    

Arán  Daniela Silvina  Harguinteguy  Carlos Alfredo  Fernandez-Cirelli  Alicia  Pignata  María Luisa 《Environmental science and pollution research international》2017,24(22):18295-18308

In order to study the bioaccumulation of Pb, Cr, Ni, and Zn and the stress response, the floating aquatic plant Limnobium laevigatum was exposed to increasing concentrations of a mixture of these metals for 28 days, and its potential use in the treatment of wastewater was evaluated. The metal concentrations of the treatment 1 (T1) were Pb 1 μg L⁻¹, Cr 4 μg L⁻¹, Ni 25 μg L⁻¹, and Zn 30 μg L⁻¹; of treatment 2 (T2) were Pb 70 μg L⁻¹, Cr 70 μg L⁻¹, Ni 70 μg L⁻¹, and Zn 70 μg L⁻¹; and of treatment 3 (T3) were Pb 1000 μg L⁻¹, Cr 1000 μg L⁻¹, Ni 500 μg L⁻¹, and Zn 100 μg L⁻¹, and there was also a control group (without added metal). The accumulation of Pb, Cr, Ni, and Zn in roots was higher than in leaves of L. laevigatum, and the bioconcentration factor revealed that the concentrations of Ni and Zn in the leaf and root exceeded by over a thousand times the concentrations of those in the culture medium (2000 in leaf and 6800 in root for Ni; 3300 in leaf and 11,500 in root for Zn). Thus, this species can be considered as a hyperaccumulator of these metals. In general, the changes observed in the morphological and physiological parameters and the formation of products of lipid peroxidation of membranes during the exposure to moderate concentrations (T2) of the mixture of metals did not cause harmful effects to the survival of the species within the first 14 days of exposure. Taking into account the accumulation capacity and tolerance to heavy metals, L. laevigatum is suitable for phytoremediation in aquatic environments contaminated with moderated concentrations of Cr, Ni, Pb, and Zn in the early stages of exposure.

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Rodríguez-Iglesias J  Vázquez I  Marañón E  Castrillón L  Sastre H 《Journal of the Air & Waste Management Association (1995)》2005,55(2):173-180

A general methodology is established that permits the characterization and evaluation of the optimum potential of biogas extraction at each vertical well in the sanitary landfill of Asturias, Spain. Twenty wells were chosen from a total of 225 for the study, and the maximum production flow of biogas, which is a result of the degradation of the municipal solid waste deposited within its area of influence, was determined for each well. It was found that this flow varied with time and is characteristic of each extraction well. The maximum extractable flow also was determined as a function of the composition of the biogas needed for its subsequent utilization. The biogas extraction yield in the wells under study varied between approximately 26 and 97%, with a mean recovery value of 82%. The low yields found in certain cases were generally caused by a sealing defect, which leads to excessive incorporation of air into the landfill gas through the surrounding soil or through the extraction shaft, and which make its subsequent utilization difficult.  相似文献