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Evaluation of heavy metal and polycyclic aromatic hydrocarbons accumulation in plants from typical industrial sites: potential candidate in phytoremediation for co-contamination 全文
2014
Sun, Lu | Liao, Xiaoyong | Yan, Xiulan | Zhu, Ganghui | Ma, Dong
The heavy metal and polycyclic aromatic hydrocarbons (PAHs) contents were evaluated in surface soil and plant samples of 18 wild species collected from 3 typical industrial sites in South Central China. The accumulative characteristics of the plant species for both heavy metal and PAHs were discussed. The simultaneous accumulation of heavy metal and PAHs in plant and soil was observed at all the investigated sites, although disparities in spatial distributions among sites occurred. Both plant and soil samples were characterized by high accumulation for heavy metal at smelting site, moderate enrichment at coke power and coal mining sites, whereas high level of PAHs (16 priority pollutants according to US Environmental Protection Agency) at coke power site, followed sequentially by coal mining and smelting sites. Based on the differences of heavy metal and PAH accumulation behaviors of the studied plant species, heavy metal and PAH accumulation strategies were suggested: Pteris vittata L. and Pteris cretica L. for As and PAHs, Boehmeria nivea (L.) Gaud for Pb, As, and PAHs, and Miscanthus floridulu (Labnll.) Warb for Cu and PAHs. These native plant species could be proposed as promising materials for heavy metal and PAHs combined pollution remediation.
显示更多 [+] 显示较少 [-]Objective classification of ecological status in marine water bodies using ecotoxicological information and multivariate analysis 全文
2014
Beiras, Ricardo | Durán, Iria
Some relevant shortcomings have been identified in the current approach for the classification of ecological status in marine water bodies, leading to delays in the fulfillment of the Water Framework Directive objectives. Natural variability makes difficult to settle fixed reference values and boundary values for the Ecological Quality Ratios (EQR) for the biological quality elements. Biological responses to environmental degradation are frequently of nonmonotonic nature, hampering the EQR approach. Community structure traits respond only once ecological damage has already been done and do not provide early warning signals. An alternative methodology for the classification of ecological status integrating chemical measurements, ecotoxicological bioassays and community structure traits (species richness and diversity), and using multivariate analyses (multidimensional scaling and cluster analysis), is proposed. This approach does not depend on the arbitrary definition of fixed reference values and EQR boundary values, and it is suitable to integrate nonlinear, sensitive signals of ecological degradation. As a disadvantage, this approach demands the inclusion of sampling sites representing the full range of ecological status in each monitoring campaign. National or international agencies in charge of coastal pollution monitoring have comprehensive data sets available to overcome this limitation.
显示更多 [+] 显示较少 [-]Toxicity of five antidepressant drugs on embryo–larval development and metamorphosis success in the Pacific oyster, Crassostrea gigas 全文
2014
Di Poi, C. | Evariste, L. | Serpentini, A. | Halm-Lemeille, M. P. | Lebel, J. M. | Costil, K.
Unlike conventional pollutants, pharmaceutical residues are continuously discharged at low levels (low to mid ng l⁻¹concentrations), which results in the chronic contamination of non-target organisms, but little is known about the effects of these residues. The purpose of this study was to provide the first assessment of the ecotoxicity of five antidepressants (selective serotonin reuptake inhibitors [SSRIs] fluoxetine and sertraline, tricyclic antidepressants [TCAs] clomipramine and amitriptyline, and serotonin norepinephrine reuptake inhibitor [SNRI] duloxetine) at a wide range of concentrations from 0.1 to 100,000 μg l⁻¹on two early life stages in the Pacific oyster. The toxicity was quantified in D-shaped larvae after 36 h of exposure, and in 21-day-old pediveliger larvae after 24 h of exposure using the percentage of normal larval development and the metamorphosis rate as endpoints, respectively. The embryotoxicity assays reported that the EC₅₀values were within the same range of concentrations (67 to 192 μg l⁻¹) for all of the tested molecules. The metamorphosis tests revealed that the antidepressants can be ranked along an increasing severity gradient: clomipramine < amitriptyline < duloxetine ~ fluoxetine. Sertraline appeared to be the less toxic molecule on this endpoint; however, a different concentration range was used. The embryotoxicity test was more sensitive than the metamorphosis bioassay for three of the five molecules tested, but the latter test showed more practical benefits. Overall, the obtained toxicity values were at least 10,000-fold higher than the reported environmental concentrations.
显示更多 [+] 显示较少 [-]Synergistic degradation of deca-BDE by an enrichment culture and zero-valent iron 全文
2014
Chen, Xingjuan | Chen, Guilan | Qiu, Mengde | Sun, Guoping | Guo, Jun | Xu, Meiying
Debromination of decabromodiphenyl ether (deca-BDE) by microbe and by zero-valent iron (ZVI) has been reported previously. However, no study has indicated the presence of microorganisms and their effect on ZVI-mediated reduction of deca-BDE. Synergistic degradation of deca-BDE by an enrichment culture and ZVI was studied. It was found that synergistic effects enhanced the debromination of deca-BDE as well as promoting the reduction of lower brominated products. ZVI stimulated microbial debromination by serving as an electron donor. Correlation analysis also confirmed that ZVI was capable of enhancing microbial population in the debromination of deca-BDE. Conversely, the enrichment culture produced acid which maintained pH stability and stimulated the oxidation of ZVI. The enrichment culture supplied its energy requirements by the oxidation of ZVI and concomitant reduction of deca-BDE, but incapable of growth and reduction of BDE-209 without ZVI and vice versa. Compared to the initial culture, the microbial community of the enrichment culture became dominated by several bacterial genera based on the results of 16S rRNA-gene pyrosequencing.
显示更多 [+] 显示较少 [-]SoilTrEC: a global initiative on critical zone research and integration 全文
2014
Menon, Manoj | Rousseva, Svetla | Nikolaidis, Nikolaos P. | van Gaans, Pauline | Panagos, Panos | de Souza, Danielle Maia | Ragnarsdottir, Kristin Vala | Lair, Georg J. | Weng, Liping | Bloem, Jaap | Kram, Pavel | Novák, Martin | Davidsdottir, Brynhildur | Guðrún Gísladóttir, | Robinson, David A. | Reynolds, Brian | White, Tim | Lundin, Lars | Zhang, Bin | Duffy, Christopher | Bernasconi, Stefano M. | de Ruiter, Peter | Blum, Winfried E. H. | Banwart, Steven A.
Soil is a complex natural resource that is considered non-renewable in policy frameworks, and it plays a key role in maintaining a variety of ecosystem services (ES) and life-sustaining material cycles within the Earth's Critical Zone (CZ). However, currently, the ability of soil to deliver these services is being drastically reduced in many locations, and global loss of soil ecosystem services is estimated to increase each year as a result of many different threats, such as erosion and soil carbon loss. The European Union Thematic Strategy for Soil Protection alerts policy makers of the need to protect soil and proposes measures to mitigate soil degradation. In this context, the European Commission-funded research project on Soil Transformations in European Catchments (SoilTrEC) aims to quantify the processes that deliver soil ecosystem services in the Earth's Critical Zone and to quantify the impacts of environmental change on key soil functions. This is achieved by integrating the research results into decision-support tools and applying methods of economic valuation to soil ecosystem services. In this paper, we provide an overview of the SoilTrEC project, its organization, partnerships and implementation.
显示更多 [+] 显示较少 [-]Elevated water temperature reduces the acute toxicity of the widely used herbicide diuron to a green alga, Pseudokirchneriella subcapitata 全文
2014
Tasmin, Rumana | Shimasaki, Yohei | Tsuyama, Michito | Qiu, Xuchun | Khalil, Fatma | Okino, Nozomu | Yamada, Naotaka | Fukuda, Shinji | Kang, Ik-Joon | Ōshima, Yūji
In the actual environment, temperatures fluctuate drastically through season or global warming and are thought to affects risk of pollutants for aquatic biota; however, there is no report about the effect of water temperature on toxicity of widely used herbicide diuron to fresh water microalgae. The present research investigated inhibitory effect of diuron on growth and photosynthetic activity of a green alga Pseudokirchneriella subcapitata at five different temperatures (10, 15, 20, 25, and 30 °C) for 144 h of exposure. As a result, effective diuron concentrations at which a 50 % decrease in algal growth occurred was increased with increasing water temperature ranging from 9.2 to 20.1 μg L–¹for 72 h and 9.4–28.5 μg L–¹for 144 h. The photochemical efficiency of photosystem II (Fᵥ/Fₘratio) was significantly reduced at all temperatures by diuron exposure at 32 μg L–¹after 72 h. Inhibition rates was significantly increased with decreased water temperature (P < 0.01). Intracellular H₂O₂levels as an indicator of oxidative stress were also decreased with increasing temperature in both control and diuron treatment groups and were about 2.5 times higher in diuron treatment groups than that of controls (P < 0.01). Our results suggest water temperatures may affect the toxicokinetics of diuron in freshwater and should therefore be considered in environmental risk assessment.
显示更多 [+] 显示较少 [-]Occurrence of 1,1′-dimethyl-4,4′-bipyridinium (Paraquat) in irrigated soil of the Lake Chad Basin, Niger 全文
2014
Crampon, Marc | Copard, Yoann | Favreau, Guillaume | Raux, Julie | Merlet-Machour, Nadine | Le Coz, Mathieu | Ibrahim, Maïmouna | Peulon-Agasse, Valérie | Portet-Koltalo, Florence
Increased use of agrochemical products to improve yields for irrigated crops in sub-Saharan Africa has been accompanied by a significant increase in the risk of environmental contamination. Detailed examples of the fate of pesticides after initial spreading on crop fields are scarce in tropical regions, where safe practices and related health risks are poorly understood by smallholder farmers. In the semi-arid environment of the Lake Chad Basin, SE Niger, both intrinsic properties of pesticides and extrinsic factors such as soil and climate helped to characterize processes leading to an accumulation of pesticides in soils. Analysis by HPLC-UV of a 6 m deep soil profile showed the presence of Paraquat at concentrations from 953 ± 102 μg kg⁻¹to 3083 ± 175 μg kg⁻¹at depths between 0.80 and 2.75 m below the land surface. Soil analysis revealed that up to approximately 15 % of the total soil matrix consists of smectites, a clay mineral capable of retaining cationic pesticides such as Paraquat, and a very low content of organic matter (<0.15 wt.% TOC). Paraquat could be stored and not bioavailable in a clayey barrier at approximately 2-m depth and therefore does not represent an immediate risk for populations or environment in this form. However, if the Paraquat application rate remains constant, the clayey barrier could reach a saturation limit within 150–200 years and 180–220 years if we consider a DT50 in soil of ~1,000 days (FAO). Consequently, it could lead to a deeper infiltration and so a pollution of groundwater. Such a scenario can represent a health risk for drinking water and for the Lake Chad, which is a major resource for this densely populated region of semi-arid Africa. Further analyses should focus on deeper layers and groundwater Paraquat contents to validate or invalidate the hypothesis of storage in this clay-rich layer.
显示更多 [+] 显示较少 [-]Kinetic study of the removal of dimethyl phthalate from an aqueous solution using an anion exchange resin 全文
2014
Xu, Zhengwen | Cheng, Ling | Shi, Jing | Lu, Jiangang | Zhang, Weiming | Zhao, Yunlong | Li, Fengying | Chen, Mindong
Phthalate acid esters are becoming an important class of pollutants in wastewaters. This study addresses the kinetics of removal of dimethyl phthalate (DMP) using the anion exchange resin D201-OH from an aqueous solution. The effects of various factors on the removal rate and efficiency were investigated. An overall initial removal rate (OIRR) law and a pseudo first-order kinetic (PFOK) model were also developed. The internal diffusion of DMP within the resin phase of D201-OH is the rate-controlling step. Optimization of the particle size and pore structure of the resin D201-OH, the DMP concentration, and the reaction temperature can improve the DMP removal rate. The hydrolysis reaction of DMP catalyzed by D201-OH indicates an overall reaction order of 1.76, a value that is between the first order and the second order. The apparent activation energy of the reaction is 34.6 kJ/mol, which is below the homogeneous alkaline hydrolysis activation energy of 44.3 kJ/mol. The OIRR law can quantify the initial removal rate under different conditions. The results also show that the theoretical DMP removal efficiency predicted by the PFOK model agrees well with the experimentally determined values. Our research provides valuable insights into the primary parameters influencing the kinetic process, which enables a focused improvement in the removal or hydrolysis rate for similar processes.
显示更多 [+] 显示较少 [-]Enhanced adsorptive removal of naphthalene intermediates from aqueous solution by introducing reed straw into sewage sludge-based activated carbon 全文
2014
Gu, Lin | Guo, Huaqing | Zhou, Pin | Zhu, Nanwen | Zhang, Daofang | Yuan, Haiping | Lou, Ziyang
The disposal of sewage sludge (SS) and reed straw (RS) has becoming a critical issue due to their rapid production. In this study, the SS-based activated carbon (SSC) was produced by introducing the RS as a component material. Properties including BET surface area, pore volume, surface chemical groups, and morphologies were characterized. The adsorption of 1-diazo-2-naphthol-4-sulfonic acid (1,2,4-Acid) and 2-Naphthol (2-Nap), which differs in their physicochemical properties, on as-prepared carbons were investigated. The overall adsorption was found to be jointly controlled by external mass transfer and intraparticle diffusion, and the optimal pH was found to be 5 due to their electrostatic attraction. Further study revealed that the SS- and RS-based carbons (SC and RSC, respectively) exhibited different adsorption behavior toward 1,2,4-Acid and 2-Nap. The calculated adsorption capacity from Langmuir–Freundlich model of SC and RSC for the two intermediates was 141.0, 84.6 mg g⁻¹and 48.2, 110.2 mg g⁻¹, respectively, whereas their hybrid product (SSC) showed comparable capacity for 1,2,4-Acid (117.8 mg g⁻¹), as well as higher capacity for 2-Nap (157.5 mg g⁻¹). It was found that the presence of meso- or macropores facilitates the precipitation of mineral phases of inorganic substances during carbonization, attracting the molecules with polar functional groups, while the introduction of C-rich RS to SS enhances the adsorption of hydrophobic molecules.
显示更多 [+] 显示较少 [-]Temporal variations and bioaccumulation of heavy metals in different Suaeda salsa marshes of the Yellow River estuary, China 全文
2014
Song, Hongli | Sun, Zhigao
To understand the temporal variations and bioaccumulation of heavy metals in the coastal marshes, the concentrations of heavy metals (Cr, Ni, Pb, and Cu) in the two Suaeda salsa marshes [middle S. salsa marsh (MM) and low S. salsa marsh (LM)] of the Yellow River estuary were determined from May to November in 2008 by in situ sampling and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Results showed that heavy metal concentrations in S. salsa of MM and LM were generally in the order of Cu > Cr > Pb > Ni, while those in sediments fell in the order of Cr > Ni > Cu > Pb. Heavy metal concentrations of S. salsa in MM and LM were different, and significant differences were observed in stems (F = 4.797, p = 0.046) and litters (F = 6.799, p = 0.026) for Ni. Litter was the main stock of heavy metals, and the allocations of Cr, Ni, and Pb reached 31.25–51.31, 28.49–42.58, and 29.55–66.79 % (in MM) and 36.73–48.60, 41.70–57.87, and 33.30–60.64 % (in LM), respectively. The ratios of roots/leaves (R/L) and roots/stems (R/S) for Cr and Ni in MM were mostly greater than 1, while those ratios in LM were mostly less than 1, indicating that Cr and Ni in S. salsa at LM had greater mobility compared with those at MM. Moreover, the [accumulation factor, AF]ₚₗₐₙₜof Cr, Ni, Cu, and Pb in LM, especially [AF]ᵣₒₒₜand [AF]ₛₜₑₘof Cr and [AF]ₗᵢₜₜₑᵣof Ni, was also higher than that in MM. These indicated that S. salsa grown in LM was more suitable for potential biomonitor or phytoremediation of Cr, Ni, Cu, and Pb if intertidal sediments were seriously contaminated with an increase of pollutant loading (especially heavy metals) in the Yellow River estuary. The use of biomonitor (S. salsa) living and growing in LM could yield valuable information not only on the presence of anthropogenic stressors, but, more importantly, on the adverse influence the stressors are having on the environment.
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