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Resultados 2401-2410 de 4,033
Green and sustainable remediation (GSR) evaluation: framework, standards, and tool. A case study in Taiwan
2016
Huang, Wen-Yen | Hung, Weiteng | Vu, Chi Thanh | Chen, Wei-Ting | Lai, Jhih-Wei | Lin, Chitsan
Taiwan has a large number of poorly managed contaminated sites in need of remediation. This study proposes a framework, a set of standards, and a spreadsheet-based evaluation tool for implementing green and sustainable principles into remediation projects and evaluating the projects from this perspective. We performed a case study to understand how the framework would be applied. For the case study, we used a spreadsheet-based evaluation tool (SEFA) and performed field scale cultivation tests on a site contaminated with total petroleum hydrocarbons (TPHs). The site was divided into two lots: one treated by chemical oxidation and the other by bioremediation. We evaluated five core elements of green and sustainable remediation (GSR): energy, air, water resources, materials and wastes, and land and ecosystem. The proposed evaluation tool and field scale cultivation test were found to efficiently assess the effectiveness of the two remediation alternatives. The framework and related tools proposed herein can potentially be used to support decisions about the remediation of contaminated sites taking into account engineering management, cost effectiveness, and social reconciliation.
Mostrar más [+] Menos [-]Are seed and dispersal characteristics of plants capable of predicting colonization of post-mining sites?
2016
Horáčková, Martina | Řehounková, Klára | Prach, Karel
Seed characteristics play an important role in the colonization and subsequent persistence of species during succession in disturbed sites and thus may contribute to being able to predict restoration success. In the present study, we investigated how various seed characteristics participated in 11 spontaneous successional series running in different mining sites (spoil heaps, extracted sand and sand-gravel pits, extracted peatlands, and stone quarries) in the Czech Republic, Central Europe. Using 1864 samples from 1- to 100-years-old successional stages, we tested whether species optimum along the succession gradient could be predicted using 10 basic species traits connected with diaspores and dispersal. Seed longevity, diaspore mass, endozoochory, and autochory appeared to be the best predictors. The results indicate that seed characteristics can predict to a certain degree spontaneous vegetation succession, i.e., passive restoration, in the mining sites. A screening of species available in the given landscape (regional and local species pools) may help to identify those species which would potentially colonize the disturbed sites. Extensive databases of species traits, nowadays available for the Central European flora, enable such screening.
Mostrar más [+] Menos [-]Land use and soil type determine the presence of the pathogen Burkholderia pseudomallei in tropical rivers
2016
Ribolzi, Olivier | Rochelle-Newall, Emma | Dittrich, Sabine | Auda, Yves | Newton, Paul N. | Rattanavong, Sayaphet | Knappik, Michael | Soulileuth, Bounsamai | Sengtaheuanghoung, Oloth | Dance, David A. B. | Pierret, Alain
Burkholderia pseudomallei is the bacterium that causes melioidosis in humans. While B. pseudomallei is known to be endemic in South East Asia (SEA), the occurrence of the disease in other parts of the tropics points towards a potentially large global distribution. We investigated the environmental factors that influence the presence (and absence) of B. pseudomallei in a tropical watershed in SEA. Our main objective was to determine whether there is a link between the presence of the organism in the hydrographic network and the upstream soil and land-use type. The presence of B. pseudomallei was determined using a specific quantitative real-time PCR assay following enrichment culture. Land use, soil, geomorphology, and environmental data were then analyzed using partial least squares discriminant analysis (PLSDA) to compare the B. pseudomallei positive and negative sites. Soil type in the surrounding catchment and turbidity had a strong positive influence on the presence (acrisols and luvisols) or absence (ferralsols) of B. pseudomallei. Given the strong apparent links between soil characteristics, water turbidity, and the presence/absence of B. pseudomallei, actions to raise public awareness about factors increasing the risk of exposure should be undertaken in order to reduce the incidence of melioidosis in regions of endemicity.
Mostrar más [+] Menos [-]An ecological vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment: system development, treatment performance, and mathematical modeling
2016
Yuan, Jiajia | Dong, Wenyi | Sun, Feiyun | Li, Pu | Zhao, Ke
An environment-friendly decentralized wastewater treatment process that is comprised of activated sludge process (ASP) and wetland vegetation, named as vegetation-activated sludge process (V-ASP), was developed for decentralized wastewater treatment. The long-term experimental results evidenced that the vegetation sequencing batch reactor (V-SBR) process had consistently stable higher removal efficiencies of organic substances and nutrients from domestic wastewater compared with traditional sequencing batch reactor (SBR). The vegetation allocated into V-SBR system could not only remove nutrients through its vegetation transpiration ratio but also provide great surface area for microorganism activity enhancement. This high vegetation transpiration ratio enhanced nutrients removal effectiveness from wastewater mainly by flux enhancement, oxygen and substrate transportation acceleration, and vegetation respiration stimulation. A mathematical model based on ASM2d was successfully established by involving the specific function of vegetation to simulate system performance. The simulation results on the influence of operational parameters on V-ASP treatment effectiveness demonstrated that V-SBR had a high resistance to seasonal temperature fluctuations and influent loading shocking.
Mostrar más [+] Menos [-]Dissipation and runoff transport of metazachlor herbicide in rapeseed cultivated and uncultivated plots in field conditions
2016
Mantzos, Nikolaos | Hela, Dimitra | Karakitsou, Anastasia | Antonopoulou, Maria | Konstantinou, Ioannis
The environmental fate of metazachlor herbicide was investigated under field conditions in rapeseed cultivated and uncultivated plots, over a period of 225 days. The cultivation was carried out in silty clay soil plots with two surface slopes, 1 and 5 %. The herbicide was detectable in soil up to 170 days after application (DAA), while the dissipation rate was best described by first-order kinetics and its half-life ranged between 10.92 and 12.68 days. The herbicide was detected in the soil layer of 10–20 cm from 5 to 48 DAA, and its vertical movement can be described by the continuous stirred tank reactor (CSTR) in series model. Relatively low amounts of metazachlor (less than 0.31 % of the initial applied active ingredient) were transferred by runoff water. More than 80 % of the total losses were transferred at the first runoff event (12 DAA), with herbicide concentrations in runoff water ranging between 70.14 and 79.67 μg L⁻¹. Minor amounts of the herbicide (less than 0.07 % of the initial applied active ingredient) were transferred by the sediment, with a maximum concentration of 0.57 μg g⁻¹ (12 DAA), in plots with 5 % inclination. Finally, in rapeseed plants, metazachlor was detected only in the first sampling (28 DAA) at concentrations slightly higher than the limit of quantification; when in seeds, no residues of the herbicide were detected.
Mostrar más [+] Menos [-]Fighting global warming by greenhouse gas removal: destroying atmospheric nitrous oxide thanks to synergies between two breakthrough technologies
2016
Ming, Tingzhen | de_Richter, Renaud | Shen, Sheng | Caillol, Sylvain
Even if humans stop discharging CO₂ into the atmosphere, the average global temperature will still increase during this century. A lot of research has been devoted to prevent and reduce the amount of carbon dioxide (CO₂) emissions in the atmosphere, in order to mitigate the effects of climate change. Carbon capture and sequestration (CCS) is one of the technologies that might help to limit emissions. In complement, direct CO₂ removal from the atmosphere has been proposed after the emissions have occurred. But, the removal of all the excess anthropogenic atmospheric CO₂ will not be enough, due to the fact that CO₂ outgases from the ocean as its solubility is dependent of its atmospheric partial pressure. Bringing back the Earth average surface temperature to pre-industrial levels would require the removal of all previously emitted CO₂. Thus, the atmospheric removal of other greenhouse gases is necessary. This article proposes a combination of disrupting techniques to transform nitrous oxide (N₂O), the third most important greenhouse gas (GHG) in terms of current radiative forcing, which is harmful for the ozone layer and possesses quite high global warming potential. Although several scientific publications cite “greenhouse gas removal,” to our knowledge, it is the first time innovative solutions are proposed to effectively remove N₂O or other GHGs from the atmosphere other than CO₂.
Mostrar más [+] Menos [-]Influence of substrate water saturation on pesticide dissipation in constructed wetlands
2016
Vallée, Romain | Dousset, Sylvie | Billet, David
Constructed wetlands are an effective and practical option for removing pesticide pollution from runoff or subsurface drainage water. The objective of this study was to assess the efficiencies of a ditch with a bundle of straw placed in its centre and a vegetated pond installed in grass cover bands at downstream of a drained plot. The dissipation rates of three herbicides and three fungicides were monitored on four substrates commonly found in constructed wetlands (two soils, sediment and straw). The influence of water content was determined in a sequence of three steps (flooded-unsaturated-flooded) over 120 days. The pesticide dissipation rates observed during the 120 days of incubation ranged from 1.4 to 100 %. Isoproturon and 2,4-MCPA (MCPA) showed the highest dissipation rates, which ranged from 61.0 to 100 % of the applied quantities during the 120 days of incubation. In contrast, boscalid and tebuconazole showed the lowest dissipation rates, which ranged from 1.4 to 43.9 % of the applied quantities during the 120 days of incubation. The estimated DT₅₀ values ranged from 20.5 days to more than 1 year and were influenced by the substrate water content. The soil and straw substrates had the lowest DT₅₀ values during the unsaturated conditions, whereas the sediments had the lowest DT₅₀ values during the flooded conditions. These results could be explained by an adaptation of microbial communities to their environmental conditions. Thus, the most favourable conditions of dissipation for soils and straw are observable when the drainage ceases (spring and summer). However, favourable conditions occur all year for the sediments, except when the constructed wetlands are dry. The results suggest that the dissipation of pesticides in constructed wetlands contributes to the long-term effectiveness of these buffer zones for reducing water pollution.
Mostrar más [+] Menos [-]Representations of pesticides and social practices: the case of French farmers
2016
Zouhri, Bouchra | Feliot-Rippeault, M. | Michel-Guillou, E. | Weiss, K.
Pesticides and their use in agriculture are important social issues. We conducted research to study the construction of this sensitive social object through the lens of social representations (study of the structural organisation of the social representations of pesticides) and their anchoring in three contexts that differ in terms of farming practices (Martinique, Brittany and Southern France). Our research was composed of two phases: hierarchical associations (n = 213) and a context independence test questionnaire (n = 124), conducted among farmers from the three study sites. The results indicate three representational fields that reflect salient issues in each agricultural territory. These illustrate the heuristic nature of social representations in the analysis of agricultural practices and pesticide use among French farmers.
Mostrar más [+] Menos [-]Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect
2016
Lalouette, Lisa | Pottier, Marie-Anne | Wycke, Marie-Anne | Boitard, Constance | Bozzolan, Françoise | Maria, Annick | Demondion, Elodie | Chertemps, Thomas | Lucas, Philippe | Renault, David | Maibeche, Martine | Siaussat, David
Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive—also called hormetic—effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure.
Mostrar más [+] Menos [-]Exploring the efficacy of wastewater-grown microalgal biomass as a biofertilizer for wheat
2016
Renuka, Nirmal | Prasanna, Radha | Sood, Anjuli | Ahluwalia, Amrik S. | Bansal, Radhika | Babu, Santosh | Singh, Rajendra | Shivay, Yashbir S. | Nain, Lata
Microalgae possess the ability to grow and glean nutrients from wastewater; such wastewater-grown biomass can be used as a biofertilizer for crops. The present investigation was undertaken to evaluate two formulations (formulation with unicellular microalgae (MC1) and formulation with filamentous microalgae (MC2); T4 and T5, respectively), prepared using wastewater-grown microalgal biomass, as a biofertilizer (after mixing with vermiculite/compost as a carrier) in wheat crop (Triticum aestivum L. HD2967) under controlled conditions. The highest values of available nitrogen (N), phosphorus (P), and potassium (K) in soil and nitrogen-fixing potential were recorded in treatment T5 (75 % N + full-dose PK + formulation with filamentous microalgae (MC2). Microbial biomass carbon was significantly enhanced by 31.8–67.0 % in both the inoculated treatments over control (recommended dose of fertilizers), with highest values in T4 (75 % N + full-dose PK + formulation with unicellular microalgae (MC1)). Both the microalgal formulations significantly increased the N, P, and K content of roots, shoots, and grains, and the highest total N content of 3.56 % in grains was observed in treatment T5. At harvest stage, the treatments inoculated with microalgal formulations (T4 and T5) recorded a 7.4–33 % increase in plant dry weight and up to 10 % in spike weight. The values of 1000-grain weight showed an enhancement of 5.6–8.4 %, compared with T1 (recommended doses of fertilizers). A positive correlation was observed between soil nutrient availability at mid crop stage and plant biometrical parameters at harvest stage. This study revealed the promise of such microalgal consortia as a biofertilizer for 25 % N savings and improved yields of wheat crop.
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