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Результаты 411-420 из 2,512
Paddy field – A natural sequential anaerobic–aerobic bioreactor for polychlorinated biphenyls transformation Полный текст
2014
Chen, Chen | Yu, Chunna | Shen, Chaofeng | Tang, Xianjin | Qin, Zhihui | Yang, Kai | Hashmi, Muhammad Zaffar | Huang, Ronglang | Shi, Huixiang
The environmental pollution and health risks caused by the improper disposal of electric and electronic waste (e-waste) have become urgent issues for the developing countries. One of the typical pollutants, polychlorinated biphenyls (PCBs), is commonly found in farmland in Taizhou, a major hotspot of e-waste recycling in China. This study investigated the amount of PCB residue in local farmlands. Biotransformation of PCBs was further studied under different water management conditions in paddy field with or without rice cultivation, with a special focus on the alternating flooded and drying processes. It was found that paddy field improved the attenuation of PCBs, especially for highly chlorinated congeners. In the microcosm experiment, 40% or more of the initial total PCBs was removed after sequential flood–drying treatments, compared to less than 10% in the sterilized control and 20% in the constant-drying system. Variation in the quantity of PCBs degrading and dechlorinating bacterial groups were closely related to the alteration of anaerobic–aerobic conditions. These results suggested that alternating anoxic–oxic environment in paddy field led to the sequential aerobic–anaerobic transformation of PCBs, which provided a favorable environment for natural PCB attenuation.
Показать больше [+] Меньше [-]Chemical characteristics of PM2.5 at a source region of biomass burning emissions: Evidence for secondary aerosol formation Полный текст
2014
Rastogi, N. | Singh, A. | Singh, D. | Sarin, M.M.
A systematic study on the chemical characteristics of ambient PM2.5, collected during October-2011 to March-2012 from a source region (Patiala: 30.2°N, 76.3°E; 250 m amsl) of biomass burning emissions in the Indo-Gangetic Plain (IGP), exhibit pronounced diurnal variability in mass concentrations of PM2.5, NO3−, NH4+, K+, OC, and EC with ∼30–300% higher concentrations in the nighttime samples. The average WSOC/OC and SO42−/PM2.5 ratios for the daytime (∼0.65, and 0.18, respectively) and nighttime (0.45, and 0.12, respectively) samples provide evidence for secondary organic and SO42− aerosol formation during the daytime. Formation of secondary NO3− is also evident from higher NH4NO3 concentrations associated with lower temperature and higher relative humidity conditions. The scattering species (SO42− + NO3− + OC) contribute ∼50% to PM2.5 mass during October–March whereas absorbing species (EC) contribute only ∼4% in October–February and subsequently increases to ∼10% in March, indicating significance of these species in regional radiative forcing.
Показать больше [+] Меньше [-]Soil removal as a decontamination practice and radiocesium accumulation in tadpoles in rice paddies at Fukushima Полный текст
2014
Sakai, Masaru | Gomi, Takashi | Nunokawa, Masanori | Wakahara, Taeko | Onda, Yūichi
We investigated the biological accumulation of radiocesium in tadpoles [Rana (Pelophylax) porosa porosa] in rice paddies with and without decontamination practice at Fukushima. Radiocesium was accumulated in surface part of soils both in the control and decontaminated paddies one year after decontamination. Mean 134Cs and 137Cs concentrations in tadpoles in the control and decontaminated paddies were 3000 and 4500, and 600 and 890 Bq/kg dry weight, respectively. Radiocesium concentrations in surface soil (0–5 cm depth) and tadpoles in the decontaminated paddy were five times smaller than in the control paddy. These results suggest that decontamination practice can reduce radiocesium concentrations in both soil and tadpoles. However, at the decontaminated paddy, radiocesium concentrations in surface soils became 3.8 times greater one year after decontamination, which indicates that monitoring the subsequent movement of radiocesium in rice paddies and surrounding areas is essential for examining contamination propagation.
Показать больше [+] Меньше [-]Evidence of sulfur-bound reduced copper in bamboo exposed to high silicon and copper concentrations Полный текст
2014
Collin, Blanche | Doelsch, Emmanuel | Keller, Catherine | Cazevieille, Patrick | Tella, Marie | Chaurand, Perrine | Panfili, Frédéric | Hazemann, Jean-Louis | Meunier, Jean-Dominique
Evidence of sulfur-bound reduced copper in bamboo exposed to high silicon and copper concentrations Полный текст
2014
Collin, Blanche | Doelsch, Emmanuel | Keller, Catherine | Cazevieille, Patrick | Tella, Marie | Chaurand, Perrine | Panfili, Frédéric | Hazemann, Jean-Louis | Meunier, Jean-Dominique
We examined copper (Cu) absorption, distribution and toxicity and the role of a silicon (Si) supplementation in the bamboo Phyllostachys fastuosa. Bamboos were maintained in hydroponics for 4 months and submitted to two different Cu (1.5 and 100 μm Cu2+) and Si (0 and 1.1 mM) concentrations. Cu and Si partitioning and Cu speciation were investigated by chemical analysis, microscopic and spectroscopic techniques. Copper was present as Cu(I) and Cu(II) depending on plant parts. Bamboo mainly coped with high Cu exposure by: (i) high Cu sequestration in the root (ii) Cu(II) binding to amino and carboxyl ligands in roots, and (iii) Cu(I) complexation with both organic and inorganic sulfur ligands in stems and leaves. Silicon supplementation decreased the visible damage induced by high Cu exposure and modified Cu speciation in the leaves where a higher proportion of Cu was present as inorganic Cu(I)S compounds, which may be less toxic.
Показать больше [+] Меньше [-]Evidence of sulfur-bound reduced copper in bamboo exposed to high silicon and copper concentrations Полный текст
2014
Collin B. | Doelsch E. | Keller C. | Cazevieille P. | Tella M. | Chaurand P. | Panfili F. | Hazemann J.L. | Meunier J.D.
We examined copper (Cu) absorption, distribution and toxicity and the role of a silicon (Si) supplementation in the bamboo Phyllostachys fastuosa. Bamboos were maintained in hydroponics for 4 months and submitted to two different Cu (1.5 and 100 mm Cu2þ) and Si (0 and 1.1 mM) concentrations. Cu and Si partitioning and Cu speciation were investigated by chemical analysis, microscopic and spectroscopic techniques. Copper was present as Cu(I) and Cu(II) depending on plant parts. Bamboo mainly coped with high Cu exposure by: (i) high Cu sequestration in the root (ii) Cu(II) binding to amino and carboxyl ligands in roots, and (iii) Cu(I) complexation with both organic and inorganic sulfur ligands in stems and leaves. Silicon supplementation decreased the visible damage induced by high Cu exposure and modified Cu speciation in the leaves where a higher proportion of Cu was present as inorganic Cu(I)S compounds, which may be less toxic. (Résumé d'auteur)
Показать больше [+] Меньше [-]Effect of air pollutant NO2 on Betula pendula, Ostrya carpinifolia and Carpinus betulus pollen fertility and human allergenicity Полный текст
2014
Cuinica, Lázaro G. | Abreu, Ilda | Esteves da Silva, Joaquim
Pollen of Betula pendula, Ostrya carpinifolia and Carpinus betulus was exposed in vitro to two levels of NO2 (about 0.034 and 0.067 ppm) – both below current atmospheric hour-limit value acceptable for human health protection in Europe (0.11 ppm for NO2). Experiments were performed under artificial solar light with temperature and relative humidity continuously monitored. The viability, germination and total soluble proteins of all the pollen samples exposed to NO2 decreased significantly when compared with the non-exposed. The polypeptide profiles of all the pollen samples showed bands between 15 and 70 kDa and the exposure to NO2 did not produce any detectable changes in these profiles. However, the immunodetection assays indicated higher IgE recognition by patient sera sensitized to the pollen extracts from all exposed samples in comparison to the non-exposed samples. The common reactive bands to the three pollen samples correspond to 58 and 17 kDa proteins.
Показать больше [+] Меньше [-]Occurrence of quaternary ammonium compounds (QACs) and their application as a tracer for sewage derived pollution in urban estuarine sediments Полный текст
2014
Li, Xiaolin | Luo, Xiaojun | Mai, Bixian | Liu, Jingqin | Chen, Li | Lin, Shanshan
Particle reactive organic contaminants in estuarine sediments can lead to various environmental problems affecting ecosystem and public health. In this study, the occurrence and homologous distribution pattern of quaternary ammonium compounds (QACs) in the surficial sediments collected from the Pearl River Estuary (PRE), China were examined along with polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs). The composition pattern of the QACs was found to be uniform in most of the sediments analyzed throughout the PRE, and the average composition pattern was identical to that determined in the sewage sludge from Guangzhou, the biggest city in the PRE. Dialkyldimethylammonium compounds, the most abundant type of QACs, positively correlated to the total concentrations of PCBs and PBDEs in most of the sediments with similar composition patterns. Therefore, the QACs are proposed as potential tracers to evaluate the transport of sewage-derived pollution in estuarine environments.
Показать больше [+] Меньше [-]Novel sensor technologies towards environmental health monitoring in urban environments: A case study in the Niger Delta (Nigeria) Полный текст
2014
Obinaju, Blessing E. | Alaoma, Alozie | Martin, Francis L.
The Niger Delta (Nigeria) is an exemplar of a legacy of environmental pollution. Limited knowledge on spatial and temporal pollutant distributions in the region highlights the need for biomonitoring approaches to study impacts on sentinel organisms. This study evaluated whether infrared (IR) spectroscopy and multivariate analysis could detect alterations in biomolecules in samples in differing exposure scenarios, i.e., spatial and temporal using African catfish (Heterobranchus bidorsalis) or water spinach (Ipomea aquatica). Significant spectral differences between tissues isolated from African catfish based on site or season were observed; in a region where fish appeared not to be present, water spinach was used as a surrogate sentinel organism. Using one-way ANOVA, the spectral categories were significant (P < 0.0001). The applicability of IR spectroscopy to detect subtle changes in target biological molecules within sentinel organisms along with its low-cost yet high-throughput potential suggests that biospectroscopy permits real-time evaluation of environmental exposure effects.
Показать больше [+] Меньше [-]Cumulative risk assessment for plasticizer-contaminated food using the hazard index approach Полный текст
2014
Chang, J.W. | Yan, B.R. | Chang, M.H. | Tseng, S.H. | Kao, Y.M. | Chen, J.C. | Lee, C.C.
Phthalates strongly and adversely affect reproduction, development and liver function. We did a cumulative risk assessment for simultaneous exposure to nine phthalates using the hazard index (HI) and the levels of nine phthalates in 1200 foodstuff samples. DEHP (di-2-ethylhexyl phthalate) present the highest level (mean: 0.443 mg/kg) in 1200 samples, and the highest average daily dose (ADD) was found in DEHP, ΣDBP(i + n) (the sum of dibutyl phthalate [DBP] isomers [DnBP + DiBP]) posed the highest risk potential of all the phthalates. In seven phthalates, the 95th percentiles of the ADDs for ΣDBP(i + n) in 0–6-yr-old children accounted for 91% (79–107%) of the tolerable daily intake, and the 95th percentiles of the HIs for the anti-androgenic effects of five phthalates in 0–3-yr-old children and 4–6-yr-old girls were >1. We conclude that the health of younger Taiwanese may be adversely affected by overexposure of phthalate-contaminated foods.
Показать больше [+] Меньше [-]Verification of NOx emission inventories over North Korea Полный текст
2014
Kim, Na Kyung | Kim, Yong Pyo | Morino, Yu | Kurokawa, Jun-ichi | Ōhara, Toshimasa
In this study, the top-down NOx emissions estimated from satellite observations of NO2 vertical column densities over North Korea from 1996 to 2009 were analyzed. Also, a bottom-up NOx emission inventory from REAS 1.1 from 1980 to 2005 was analyzed with several statistics. REAS 1.1 was in good agreement with the top-down approach for both trend and amount. The characteristics of NOx emissions in North Korea were quite different from other developed countries including South Korea. In North Korea, emissions from industry sector was the highest followed by transportation sector in the 1980s. However, after 1990, the NOx emissions from other sector, mainly agriculture, became the 2nd highest. Also, no emission centers such as urban areas or industrial areas were distinctively observed. Finally, the monthly NOx emissions were high during the warm season.
Показать больше [+] Меньше [-]Are persistent organic pollutants and metals in eel muscle predictive for the ecological water quality? Полный текст
2014
Van Ael, Evy | Belpaire, Claude | Breine, Jan | Geeraerts, Caroline | Van Thuyne, Gerlinde | Eulaers, Igor | Blust, Ronny | Bervoets, Lieven
Relationships between the presence of PCBs, OCPs and metals in aquatic ecosystems and the ecological water quality were investigated by combining datasets of long-term monitoring of chemicals in European eel (Anguilla anguilla, N = 1156) in Flanders (Belgium) and the Ecological Quality Ratio (EQR), based on the assessment of fish assemblages at 185 locations. For most pollutants, EQR scores were lower when pollutant levels were higher. Threshold concentrations for a good quality could be formulated for PCB's, most metals and OCPs. Mixed models suggested that the ecological water quality was significantly correlated with the presence of PCBs. However, the low R2 indicates that other environmental pressures may significantly influence the biotic integrity of fish communities. Empirical data and their analyses are essential to enable defining threshold values of bioaccumulated levels to allow better protection of the aquatic environment and its biota through associated food webs as demanded by the Water Framework Directive.
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