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Результаты 1241-1250 из 1,956
Relative Contribution of Endocrine-disrupting Chemicals to the Estrogenic Potency of Marine Sediments of Osaka Bay, Japan Полный текст
2013
Koyama, Jiro | Kitoh, Asami | Nakai, Makoto | Kohno, Kumiko | Tanaka, Hiroyuki | Uno, Seiichi
Although concentrations of endocrine-disrupting chemicals (EDCs) in seawaters of Japan are relatively low, vitellogenin and ovotestis inductions are still being observed in some males of mullet and flounder collected in coastal areas. These fish species are benthic and could be affected by EDCs in marine sediments. Therefore, the concentrations of EDCs in marine sediments of Osaka Bay were determined by LC-MS/MS. In addition, the estrogen receptor binding potencies as estrogenic potencies of these sediments were assessed by the medaka estrogen receptor-α binding assay. Results show that estrogenic potencies were higher in sediments of the inner part of the bay especially at station 13 (off Sakai City) where quite strong estrogenic potency was detected. Through calculation of total E2 equivalent concentration (EEQ) in sediments, it was established that approximately 50 % of estrogenic potency was due to nonylphenol (NP), estrone and 17β-estradiol, suggesting that these compounds play important roles as endocrine disruptors in coastal environments of Osaka Bay.
Показать больше [+] Меньше [-]Phytotoxicity of Long-Term Total Petroleum Hydrocarbon-Contaminated Soil—A Comparative and Combined Approach Полный текст
2013
Masakorala, Kanaji | Yao, Jun | Kwok, Woon | Chandankere, Radhika | Wang, Jingwei | Cai, Minmin | Liu, Haijun | Choi, Martin M. F.
Petroleum hydrocarbon contamination of soil is an emerging environmental threat on the Earth due to possible toxic impact on different ecological receptors. The present study was mainly carried out to evaluate the phytotoxicity of long-term total petroleum hydrocarbon-contaminated soils by the toxicity end points obtained from three plant species Zea mays, Lactuca sativa L., and Cucumis sativus. The tested soil exerted phytotoxicity for all the evaluated end points of plants with dose-dependent relationship. The determined IC₅₀ indicates inhibition in root elongation as the most sensitive toxicity end point for L. sativa L., while inhibition in cross-section area of meristematic zone as the most susceptible and inhibition in seed germination as the least susceptible end points for both Z. mays and C. sativus. The tested root morphometric parameters confirm their applicability as novel toxicity end points. In addition, microcalorimetric analysis confirmed the applicability of inhibition in metabolic heat emission rate as a toxicity end point. Microcalorimetry can be applied to determine the exerted phytotoxic effect on seedlings. The present combined approach concludes that the phytotoxicity of the tested soil is species-specific and varies as follows: Z. mays < C. sativus < L. sativa L. The findings of this study may have implications in planning comprehensive phytotoxicity assessment for hydrocarbon-contaminated soils or screening plant species for phytoremediation program.
Показать больше [+] Меньше [-]TiO₂/T-PVA Composites Immobilized on Cordierite: Structure and Photocatalytic Activity for Degrading RhB Under Visible Light Полный текст
2013
Zhang, Jian-ling | Song, Yuanqing | Yang, Haigang | Xu, Shoubin | Jiang, Long | Dan, Yi
A novel immobilized visible light-active photocatalyst (TiO₂/polyvinyl alcohol after thermal treatment (T-PVA)/cordierite honeycomb (CHC)) was successfully prepared by a simple and convenient method combining sol–gel and thermal treatment using tetrabutyl titanate (TBOT) as the titanium source, polyvinyl alcohol (PVA) as the precursor of conjugated polymer, and CHC as the support. The synthesized photocatalyst was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, and field emission scanning electron microscopy. The results showed that PVA was dehydrated to produce conjugated unsaturated T-PVA. The T-PVA not only extended the response spectrum of TiO₂ to visible light region, but also strengthened the adhesion of TiO₂ to CHC. The TiO₂/T-PVA/CHC showed both outstanding adsorption properties and excellent photocatalytic performance under visible light on the decolorization of Rhodamine B. Over eight cycles, the photocatalyst continued to maintain perfect photocatalytic activity, showing good stability.
Показать больше [+] Меньше [-]RETRACTION: Fate and Transport of EDCs in Soils: Estrone and Its Sulfate Conjugate's Adsorption from Mediator Solutions Полный текст
2013
Mohammed, Alkali | Yang, Y. S. | Du, X. Q. | Musa, A.
The fate and transport of emerging contaminants have been major concerns for ecoenvironment and human health. This study presents the adsorption behavior of an endocrine disrupting chemical estrone (E1) and its sulfate conjugate estrone-3-sulfate (E1-3S) that are released to the environment via animal waste in significant amounts and direct exposures in grazed pasture systems. Both compounds have been shown to potentially contribute to endocrine disruption in wildlife, and knowledge about the adsorption behavior of these compounds is necessary for a sound environmental risk assessment. For labile compounds such as E1 and E1-3S, however, the standard protocols might overestimate adsorption by not considering metabolite formation or allowing for equilibration that exceeds the commonly reported half-lives of these compounds. Modified batch adsorption experiments with mediator solution of 0.005 M calcium chloride (CaCl₂) and artificial urine (AU) solution were, therefore, conducted to determine the influence of these mediator solutions on the adsorption of E1 and E1-3S in three agricultural soils from Nasarawa State of Nigeria. Adsorption isotherms of both compounds were nonlinear, and the Freundlich equation was found adequate to describe the isotherms. The calculation of concentration-dependent effective distribution coefficients (K d ᵉᶠᶠ) revealed that for a range of realistic exposure concentrations in a grazed farming system, the common approach of using CaCl₂ would deliver incorrect information for a sound risk assessment.
Показать больше [+] Меньше [-]Estimating In Situ Biodegradation Rates of Petroleum Hydrocarbons and Microbial Population Dynamics by Performing Single-Well Push–Pull Tests in a Fractured Bedrock Aquifer Полный текст
2013
Cho, Yunchul | Han, Kyungjin | Kim, Namhee | Park, Sunhwa | Kim, Young
The single-well push–pull test (SWPPT) was adapted to quantify in situ aerobic respiration and denitrification rates and to assess microbial population dynamics in a petroleum-contaminated fractured bedrock aquifer. Among three test wells, significant dissolved oxygen (DO) consumption was observed only in one well, with average zero- and first-order rate coefficients of 0.32 ± 0.63 and 7.07 ± 13.85 mmol L⁻¹ day⁻¹, respectively. Of the four test wells, significant NO₃ ⁻ consumption was noted in three wells. The average zero- and first-order rate coefficients were 2.87 ± 2.21 and 11.83 ± 7.99 mmol L⁻¹ day⁻¹, respectively. These results indicate that NO₃ ⁻ was more effectively consumed within this fractured bedrock aquifer. Significant DO or NO₃ ⁻ (electron acceptors (EAs)) consumption, the limited contribution of Fe(II) to overall EAs consumption, the production of dissolved CO₂ during aerobic respiration and denitrification tests, and N₂O production strongly suggest that the EAs consumption was largely due to microbial activity. Detection of Variovorax paradox, benzene-degrading culture, and 28 novel microbial species after the addition of O₂ or NO₃ ⁻ suggests that EA injection into a fractured rock aquifer may stimulate aerobic or denitrifying petroleum-degrading microbes. Therefore, SWPPT may be useful for quantifying in situ aerobic respiration and denitrification rates and for assessing microbial population dynamics in petroleum-contaminated fractured bedrock aquifers.
Показать больше [+] Меньше [-]Bioelectricity Generation from Palm Oil Mill Effluent in Microbial Fuel Cell Using Polacrylonitrile Carbon Felt as Electrode Полный текст
2013
Baranitharan, E. | Khan, Maksudur R. | Prasad, D. M. R. | Salihon, Jailani Bin
Palm oil mill effluent (POME) is an organic waste material produced at the oil palm mills. In its raw form, POME is highly polluting due to its high content of biological and chemical oxygen demand. In the present paper, POME was treated using double chamber microbial fuel cell with simultaneous generation of electricity. Polyacrylonitrile carbon felt (PACF), a new electrode material was used as electrode throughout the MFC experiments. Various dilutions of raw POME were used to analyze the effect of initial chemical oxygen demand (COD) on MFC power generation, COD removal efficiency and coulombic efficiency. Anaerobic sludge was used as inoculum for all the MFC experiments. Since this inoculum originated from POME, it showed higher potential to generate bioenergy from complex POME. Anaerobic sludge enhanced the power production due to better utilization of substrates by various types of microorganisms present in it. Among the raw POME and different concentrations of POME used, the PACF with raw POME showed the maximum power density and volumetric power density of about 45 mW/m² and 304 mW/m³, respectively, but it showed low coulombic efficiency and low COD removal efficiency of about 0.8 % and 45 %, respectively. The MFC PACF with 1:50 dilution showed higher COD removal efficiency and coulombic efficiency of about 70 % and 24 % but showed low power density and low volumetric power density of about 22 mW/m² and 149 mW/m³, respectively. The formation of biofilm onto the electrode surface has been confirmed from scanning electron microscopy (SEM) experiments. The results confirm that MFC possesses great potential for the simultaneous treatment of POME and power generation using PACF as electrode and also shows that initial COD has great influence on coulombic efficiency, COD removal efficiency and power generation.
Показать больше [+] Меньше [-]Trace Metal Contamination Due to Acid Rock Drainage and Its Impacts on the Fish-Bearing Pennask Creek Watershed, British Columbia Полный текст
2013
Walls, Lisa D. | Li, Loretta Y. | Hall, Kenneth J.
The Pennask Creek watershed in British Columbia (BC), Canada has been contaminated with acid rock drainage (ARD) and associated metal leaching (ML) as a result of highway construction. By combining existing and newly gathered information, this study determined the extent of metal contamination of the water and sediments, the potential biological impacts of this contamination, the influence of local geology, and estimated the potential risk to aquatic organisms. Surface water and sediment samples from the watershed were analyzed for general chemical parameters and trace metals. Rock samples were analyzed for mineralogy and chemical composition. Metal concentrations in water and sediments downstream of the ARD/ML source were higher than elsewhere in the watershed. Metals of concern include aluminum (Al), copper (Cu), and zinc (Zn). Analysis of historical water quality data indicated that the concentrations of these metals have decreased markedly since 2004, due to remediation efforts. Rock samples collected from the streambeds and banks were not found to be potentially acid generating, but did contain significant levels of metals. Al, Cu, and Zn levels consistently exceeded BC water and sediment quality guidelines for the protection of aquatic life, indicating that adverse biological effects are probable at stations downstream of the ARD/ML source. Benthic invertebrate monitoring over a 10-year period showed low abundance and diversity and a complete absence of sensitive taxa at downstream stations. Risk quotients indicated a likelihood of adverse biological effects for aquatic organisms, including rainbow trout, due to metal contamination in the watershed.
Показать больше [+] Меньше [-]Relationship Between Atmospheric Dissolved Deposition and Mineral Dust Deposition in French Forests Полный текст
2013
Lequy, Émeline | Nicolas, Manuel | Conil, Sébastien | Turpault, Marie-Pierre
Relationship Between Atmospheric Dissolved Deposition and Mineral Dust Deposition in French Forests Полный текст
2013
Lequy, Émeline | Nicolas, Manuel | Conil, Sébastien | Turpault, Marie-Pierre
Calcium dissolved deposition shows an unusual spatial structure in France, probably due to the contribution of southern air masses from Mediterranean Sea and Saharan desert. These masses are often loaded with terrigenous particles that contain carbonates. However, no precise relationship has been quantified between dissolved Ca and mineral dust deposition (MDD). The database of the French network RENECOFOR, gathering atmospheric deposition <0.45 mu m in 27 sites near forests during 18 years, was used to determine the non-sea-salt atmospheric deposition over France. This study (1) explores the relationship between dissolved components to decipher their origin in atmospheric deposition nearby forests and (2) tests the use of dissolved Ca and Mg as proxies for MDD. In the RENECOFOR database, non-sea-salt Ca (nssCa) preferentially deposited between May and August. MDD observed in RENECOFOR was synchronic with high nssCa deposition, particularly in June 2008, when air mass highly loaded with Saharan dust covered France. The dissolution of this mineral dust likely contributed to the nssCa deposition of this period and suggested a relationship between the depositions of nssCa and MDD. Then, MDD was specifically sampled with dissolved deposition in four sampling sites. Encouraging relationships were found between MDD and the depositions of nssMg and nssCa, suggesting that the latter could be used as a proxy for MDD in regions where it is not monitored, and in a retrospective approach in order to calculate nutrient fluxes.
Показать больше [+] Меньше [-]Relationship Between Atmospheric Dissolved Deposition and Mineral Dust Deposition in French Forests Полный текст
2013
Lequy, Emeline | Nicolas, Manuel | Conil, Sébastien | Turpault, Marie-Pierre, M.-P. | Unité de recherche Biogéochimie des Ecosystèmes Forestiers (BEF) ; Institut National de la Recherche Agronomique (INRA) | Observ Perenne Environm, DRD Observat Surveillance ; Agence Nationale pour la Gestion des Déchets Radioactifs (ANDRA) | Direct Tech & Commerciale Boi ; Partenaires INRAE | Andra; GIP ECOFOR
International audience | Calcium dissolved deposition shows an unusual spatial structure in France, probably due to the contribution of southern air masses from Mediterranean Sea and Saharan desert. These masses are often loaded with terrigenous particles that contain carbonates. However, no precise relationship has been quantified between dissolved Ca and mineral dust deposition (MDD). The database of the French network RENECOFOR, gathering atmospheric deposition <0.45 mu m in 27 sites near forests during 18 years, was used to determine the non-sea-salt atmospheric deposition over France. This study (1) explores the relationship between dissolved components to decipher their origin in atmospheric deposition nearby forests and (2) tests the use of dissolved Ca and Mg as proxies for MDD. In the RENECOFOR database, non-sea-salt Ca (nssCa) preferentially deposited between May and August. MDD observed in RENECOFOR was synchronic with high nssCa deposition, particularly in June 2008, when air mass highly loaded with Saharan dust covered France. The dissolution of this mineral dust likely contributed to the nssCa deposition of this period and suggested a relationship between the depositions of nssCa and MDD. Then, MDD was specifically sampled with dissolved deposition in four sampling sites. Encouraging relationships were found between MDD and the depositions of nssMg and nssCa, suggesting that the latter could be used as a proxy for MDD in regions where it is not monitored, and in a retrospective approach in order to calculate nutrient fluxes.
Показать больше [+] Меньше [-]The Removal of Cyanide Ions from Aquatic Environments by Quaternizable p(4-VP) Hydrogels of Different Dimensions Полный текст
2013
Sahiner, Nurettin | Ozay, Ozgur | Aktas, Nahit
Hydrogels based on p(4-VP) of different dimensions were prepared and, after chemical modification, were used in the removal of one of the most potent toxic materials, cyanide. Macro and micron p(4-VP) hydrogel swelling behavior was evaluated in various aquatic environments. HCl, bromoethane, 1-bromobutane, 1-bromohexane, and 2-bromoethylamine were used as quaternizing agents to generate positive charges on both p(4-VP) macrogels and microgels. The modified p(4-VP) macrogels and microgels were used in cyanide ion removal for the first time from aqueous environments. The p(4-VP)-HCl at macro and micro sizes removed almost 49 and 61 mg cyanide ions per gram hydrogel in deionized water after modification, respectively. Moreover, the absorption capacity of the modified p(4-VP) hydrogel did not change significantly in tap, drinking, and creek waters. Parameters that affect the absorption process, such as cyanide concentration, contact time, hydrogel amount, and contaminated water source, were investigated. Additionally, magnetic field responsive macro and micro p(4-VP) hydrogel composites provided many advantages, such as easy handling after cyanide absorption, e.g., ready removal of cyanide-loaded p(4-VP) composites with an externally applied magnetic field. Langmuir and Freundlich adsorption isotherms were applied to the data obtained for cyanide uptake from aqueous environments.
Показать больше [+] Меньше [-]Evaluation of the Effect of Surface Ozone on Main Crops in East Asia: 2000, 2005, and 2020 Полный текст
2013
Amin, Nawahda | Ken, Yamashita | Toshimasa, Ohara | Junichi, Kurokawa | Kazuyo, Yamaji
In this paper, the possible effect of surface ozone on soybean, wheat, rice, and maize crops in East Asia in 2000, 2005, and 2020 is estimated. Spatial distribution and temporal variation of surface ozone concentrations are simulated using the Models-3 Community Multiscale Air Quality Modeling System coupled with the Regional Emission Inventory in Asia (CMAQ/REAS). The effect of surface ozone on main crops in East Asia is evaluated based on accumulated exposure over a threshold of 40 ppb (AOT40 index) during a period of 3 months of the growing season. We demonstrate some of the implications for policy-making in air quality management for East Asia by highlighting the effect of elevated surface ozone concentrations on harvest losses and the corresponding value of the main crops. These concentrations are calculated based on three scenarios of emission reduction policies in 2020: policy success case (PSC), reference case (REF), and policy failure case (PFC). Assuming no future changes in land use or cropping patterns from 2000 to 2020, we find that the highest relative yield (RY) losses are in wheat and soybean in East Asia. The RY losses for wheat are estimated to range between 17 and 35 % in 2000, 21 and 49 % in 2005, 18 and 36 % in 2020 (PSC), 20 and 46 % in 2020 (REF), and 22 and 62 % in 2020 (PFC); the corresponding values for rice are 6 and 12 %, 6 and 17 %, 6 and 15 %, 6 and 17 %, and 7 and 20 %; for soybean, they are 12 and 16 %, 19 and 25 %, 18 and 33 %, 21 and 40 %, and 25 and 49 %; and for maize, they are 3 and 4 %, 5.7 and 6 %, 6 and 9 %, 9 and 11 %, and 12 and 14 %. Quantitatively, the estimated losses in production of wheat in East Asia in 2000, 2005, and 2020 (PSC, REF, and PFC scenarios) are 32.4, 44.3, 42.2, 54.0, and 72.3 t, respectively; for rice, 34.9, 39.4, 42.4, 46.5, and 54.6 mmt; for soybean, 1.9, 3.3, 3.6, 4.9, and 7.0 mmt; and for maize, 3.6, 8.1, 11.4, 15.4, and 21.5 mmt. The estimated values of crop losses in East Asia in 2000, 2005, and 2020 (PSC, REF, and PFC scenarios) are as follows: 13.8, 17.4, 18.2, 21.3, and 26.7 billion Int. $. Therefore, adaptation measures in the PSC scenario in contrast to the PFC scenario could save around 8.5 billion Int. $ across East Asian countries in 2020.
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