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Результаты 2111-2120 из 3,197
Public budgets for energy RD&D and the effects on energy intensity and pollution levels
2015
Balsalobre-Lorente, Daniel | Álvarez, Agustín | Cantos, José María
This study, based on the N-shaped cubic model of the environmental Kuznets curve, analyzes the evolution of per capita greenhouse gas emissions (GHGpc) using not just economic growth but also public budgets dedicated to energy-oriented research development and demonstration (RD&D) and energy intensity. The empirical evidence, obtained from an econometric model of fixed effects for 28 OECD countries during 1994–2010, suggests that energy innovations help reduce GHGpc levels and mitigate the negative impact of energy intensity on environmental quality. When countries develop active energy RD&D policies, they can reduce both the rates of energy intensity and the level of GHGpc emissions. This paper incorporates a moderating variable to the econometric model that emphasizes the effect that GDP has on energy intensity. It also adds a variable that reflects the difference between countries that have made a greater economic effort in energy RD&D, which in turn corrects the GHG emissions resulting from the energy intensity of each country.
Показать больше [+] Меньше [-]Chromium exposure among children from an electronic waste recycling town of China
2015
Xu, Xijin | Yekeen, Taofeek Akangbe | Liu, Junxiao | Zhuang, Bingrong | Li, Weiqiu | Huo, Xia
Guiyu is one of the most heavily chromium-polluted areas in China due to the numerous informal electronic waste (e-waste) recycling activities. A 3-year (2004, 2006, and 2008) independent cross-sectional study on blood chromium (BCr) levels of 711 children from Guiyu and a control area was investigated. Questionnaire completed by parents/guardians was used to assess the risk factors of chromium (Cr) exposure, while physical examination, for the year 2008 only, was used to evaluate the effects of long-term exposure to Cr on child physical development. Children living in Guiyu had significantly higher BCr levels compared with those living in Chendian at the same period from 2004 to 2008 (P < 0.001). The predominant risk factors related to elevated child BCr levels included the use of house as a family workshop, parent involved in e-waste recycling, and child residence in Guiyu. Children’s weight and chest circumferences in group with high exposure to Cr (upper quartile) were higher than in the low-exposure group (P < 0.01), although the difference was less significant for boys between the two groups (P < 0.05). The results suggest that elevated child BCr in Guiyu due to informal e-waste recycling activities might be threatening the health of children, with implications on physical growth and development.
Показать больше [+] Меньше [-]Occurrence of perfluorinated alkyl substances in sediment from estuarine and coastal areas of the East China Sea
2015
Yan, Hong | Zhang, Chaojie | Zhou, Qi | Yang, Shouye
Perfluorinated alkyl substances (PFAS) have drawn much attention due to their environmental persistence, ubiquitous existence, and bioaccumulation potential. The occurrence and spatial variation of PFAS were investigated through collection of riverine and marine sediments from estuarine and coastal areas of the East China Sea. Among them, perfluorooctanesulfonic acid (PFOS), perfluoroheptanoic acid (PFHpA), and perfluorooctanoic acid (PFOA) were the three predominant PFAS with the highest detection frequencies in the sediment. PFOS up to 32.4 ng g⁻¹ dw and ∑PFAS up to 34.8 ng g⁻¹ dw were detected. Compared to other studies, high levels of PFOS were found in sediments from the East China Sea. PFHpA was also detected at higher frequency and concentration than those of other studies, which suggests point sources in this area. Concentrations of PFAS in riverine sediments were much higher than in marine sediments. Analysis of spatial variations presented overall decreasing trends of PFAS from inshore to offshore areas.
Показать больше [+] Меньше [-]Changes in bacterial community metabolism and composition during the degradation of dissolved organic matter from the jellyfish Aurelia aurita in a Mediterranean coastal lagoon
2015
Blanchet, Marine | Pringault, Olivier | Bouvy, Marc | Catala, Philippe | Oriol, Louise | Caparros, Jocelyne | Ortega-Retuerta, Eva | Intertaglia, Laurent | West, Nyree | Agis, Martin | Got, Patrice | Joux, Fabien
Spatial increases and temporal shifts in outbreaks of gelatinous plankton have been observed over the past several decades in many estuarine and coastal ecosystems. The effects of these blooms on marine ecosystem functioning and particularly on the dynamics of the heterotrophic bacteria are still unclear. The response of the bacterial community from a Mediterranean coastal lagoon to the addition of dissolved organic matter (DOM) from the jellyfish Aurelia aurita, corresponding to an enrichment of dissolved organic carbon (DOC) by 1.4, was assessed for 22 days in microcosms (8 l). The high bioavailability of this material led to (i) a rapid mineralization of the DOC and dissolved organic nitrogen from the jellyfish and (ii) the accumulation of high concentrations of ammonium and orthophosphate in the water column. DOM from jellyfish greatly stimulated heterotrophic prokaryotic production and respiration rates during the first 2 days; then, these activities showed a continuous decay until reaching those measured in the control microcosms (lagoon water only) at the end of the experiment. Bacterial growth efficiency remained below 20 %, indicating that most of the DOM was respired and a minor part was channeled to biomass production. Changes in bacterial diversity were assessed by tag pyrosequencing of partial bacterial 16S rRNA genes, DNA fingerprints, and a cultivation approach. While bacterial diversity in control microcosms showed little changes during the experiment, the addition of DOM from the jellyfish induced a rapid growth of Pseudoalteromonas and Vibrio species that were isolated. After 9 days, the bacterial community was dominated by Bacteroidetes, which appeared more adapted to metabolize high-molecular-weight DOM. At the end of the experiment, the bacterial community shifted toward a higher proportion of Alphaproteobacteria. Resilience of the bacterial community after the addition of DOM from the jellyfish was higher for metabolic functions than diversity, suggesting that jellyfish blooms can induce durable changes in the bacterial community structure in coastal lagoons.
Показать больше [+] Меньше [-]Response of plasma membrane H+-ATPase in rice (Oryza sativa) seedlings to simulated acid rain
2015
Liang, Chanjuan | Ge, Yuqing | Su, Lei | Bu, Jinjin
Understanding the adaptation of plants to acid rain is important to find feasible approaches to alleviate such damage to plants. We studied effects of acid rain on plasma membrane H⁺-ATPase activity and transcription, intracellular H⁺, membrane permeability, photosynthetic efficiency, and relative growth rate during stress and recovery periods. Simulated acid rain at pH 5.5 did not affect plasma membrane H⁺-ATPase activity, intracellular H⁺, membrane permeability, photosynthetic efficiency, and relative growth rate. Plasma membrane H⁺-ATPase activity and transcription in leaves treated with acid rain at pH 3.5 was increased to maintain ion homeostasis by transporting excessive H⁺ out of cells. Then intracellular H⁺ was close to the control after a 5-day recovery, alleviating damage on membrane and sustaining photosynthetic efficiency and growth. Simulated acid rain at pH 2.5 inhibited plasma membrane H⁺-ATPase activity by decreasing the expression of H⁺-ATPase at transcription level, resulting in membrane damage and abnormal intracellular H⁺, and reduction in photosynthetic efficiency and relative growth rate. After a 5-day recovery, all parameters in leaves treated with pH 2.5 acid rain show alleviated damage, implying that the increased plasma membrane H⁺-ATPase activity and its high expression were involved in repairing process in acid rain-stressed plants. Our study suggests that plasma membrane H⁺-ATPase can play a role in adaptation to acid rain for rice seedlings.
Показать больше [+] Меньше [-]Pollutant toxicity and detoxification by humic substances: mechanisms and quantitative assessment via luminescent biomonitoring
2015
Kudryasheva, N. S. | Tarasova, A. S.
The paper considers mechanisms of detoxification of pollutant solutions by water-soluble humic substances (HSs), natural detoxifying agents. The problems and perspectives of bioassay application for toxicity monitoring of complex solutions are discussed from ecological point of view. Bioluminescence assays based on marine bacteria and their enzymes are of special attention here; they were shown to be convenient tools to study the detoxifying effects on cellular and biochemical levels. The advantages of bioluminescent enzymatic assay for monitoring both integral and oxidative toxicities in complex solutions of model pollutants and HS were demonstrated. The efficiencies of detoxification of the solutions of organic oxidizers and salts of metals (including radioactive ones) by HS were analyzed. The dependencies of detoxification efficiency on time of exposure to HS and HS concentrations were demonstrated. Antioxidant properties of HS were considered in detail. The detoxifying effects of HS were shown to be complex and regarded as ‘external’ (binding and redox processes in solutions outside the organisms) and/or ‘internal’ organismal processes. The paper demonstrates that the HS can stimulate a protective response of bacterial cells as a result of (1) changes of rates of biochemical reactions and (2) stabilization of mucous layers outside the cell walls. Acceleration of auto-oxidation of NADH, endogenous reducer, by HS was suggested as a reason for toxicity increase in the presence of HS due to abatement of reduction ability of intracellular media.
Показать больше [+] Меньше [-]Evaluation of ettringite-related swelling mechanisms for treated chromite ore processing residue
2015
Moon, Deok Hyun | Wazne, Mahmoud | Dermatas, Dimitris | Sanchez, Adriana M. | Cheong, Kyung Hoon | Park, Jeong-Hun
Accelerated one-dimensional unconfined swell tests were conducted for ferrous sulfate chromite ore processing residue (COPR) field-treated samples. The field-treated samples were subjected to wet and dry cycles over 100 days to accelerate the lithification of the samples. Parallel laboratory experiments were performed to investigate the effects of mineralogy on COPR swell under controlled conditions. The field and laboratory samples were treated with ferrous sulfate at a ferrous-to-Cr⁶⁺ molar stoichiometric ratios of eight (8×) and five (5×). X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) analyses were used to investigate the mineralogical changes upon treatment. The swell results indicated that significant COPR swelling was observed in all of the tested samples. The swelling was more pronounced in the 5× treated COPR sample than in the 8× treated COPR sample. Moreover, the laboratory-treated samples showed greater swelling behavior as compared with the field-treated samples, which was most probably due to the high dry density of the COPR, indicating that dry density was a more dominant factor than lithification. XRPD and SEM-EDX results confirmed that significant ettringite formation occurred in all treated samples.
Показать больше [+] Меньше [-]Solar energy for wastewater treatment: review of international technologies and their applicability in Brazil
2015
Marcelino, R. B. P. | Queiroz, M. T. A. | Amorim, C. C. | Leão, M. M. D. | Brites-Nóbrega, F. F.
Several studies have reported the adverse effects of recalcitrant compounds and emerging contaminants present in industrial effluents, which are not degradable by ordinary biological treatment. Many of these compounds are likely to accumulate in living organisms through the lipid layer. At concentrations above the limits of biological tolerance, these compounds can be harmful to the ecosystem and may even reach humans through food chain biomagnification. In this regard, advanced oxidation processes (AOPs) represent an effective alternative for the removal of the pollutants. This study focused on the AOP involving the use of ultraviolet radiation in homogeneous and heterogeneous systems. Based on the literature review, comparisons between natural and artificial light were established, approaching photoreactors constructive and operational characteristics. We concluded that the high availability of solar power in Brazil would make the implementation of the AOP using natural solar radiation for the decontamination of effluents feasible, thereby contributing to clean production and biodiversity conservation. This will serve as an important tool for the enforcement of environmental responsibility among public and private institutions.
Показать больше [+] Меньше [-]Necrotic bark of common pine (Pinus sylvestris L.) as a bioindicator of environmental quality
2015
Chrzan, Anna
The aim of this study was to determine the pH and the concentration of lead, cadmium, nickel, copper and zinc in aqueous extracts of necrotic bark Pinus sylvestris L. and in adjacent soil, located in two types of forest habitat in different parts in the Niepołomice Forest in southern Poland. The Niepołomice Forest is located about 35 km east of an urban-industrial agglomeration Kraków. Despite the lack of significant differences in pine bark reaction studied, there was a clear difference in contamination of both bark and soil with heavy metals. There was a correlation between the distribution of pollutants in the forest, and the direction of the prevailing winds. More heavy metals were accumulated in the pine bark and soil from the west than the east. The high content of lead, zinc, cadmium and copper in the soils most likely results from the inflow of gas and dust pollutants from the urban-industrial agglomeration of Kraków.
Показать больше [+] Меньше [-]Application of molecularly imprinted polymers in wastewater treatment: a review
2015
Huang, Dan-Lian | Wang, Rong-Zhong | Liu, Yun-Guo | Zeng, Guang-Ming | Lai, Cui | Xu, Piao | Lu, Bing-An | Xu, Juan-Juan | Wang, Cong | Huang, Chao
Molecularly imprinted polymers are synthetic polymers possessing specific cavities designed for target molecules. They are prepared by copolymerization of a cross-linking agent with the complex formed from a template and monomers that have functional groups specifically interacting with the template through covalent or noncovalent bonds. Subsequent removal of the imprint template leaves specific cavities whose shape, size, and functional groups are complementary to the template molecule. Because of their predetermined selectivity, molecularly imprinted polymers (MIPs) can be used as ideal materials in wastewater treatment. Especially, MIP-based composites offer a wide range of potentialities in wastewater treatment. This paper reviews the latest applications of MIPs in wastewater treatment, highlights the development of MIP-based composites in wastewater, and offers suggestions for future success in the field of MIPs.
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