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Phytotoxicity of nanoparticles—problems with bioassay choosing and sample preparation Texte intégral
2014
Jośko, Izabela | Oleszczuk, Patryk
For a full estimation of the risk related with the presence of engineered nanoparticles (ENPs) in the environment, the use of the current ecotoxicological methods may prove insufficient. In the study presented herein, various methods of assessment of ecotoxicity were applied to compare the phytotoxicity of three ENPs: nano-ZnO, nano-TiO₂ and nano-Ni. The toxicity was assayed both for aqueous solutions of the ENPs (the germination/elongation test and Phytotestkit Fᵀᴹ) and for ENPs added to soil (Phytotoxkit Fᵀᴹ and modified Phytotoxkit Fᵀᴹ). Lepidium sativum was used as a test plant. The scope of the study also included the assessment of the effect of the method of ENP application to the soil (as powder and aqueous suspension) on their phytotoxicity. In the course of the study, no effect of the studied ENPs and their bulk counterparts on the germination of seeds was observed. The root growth inhibition of L. sativum depended on the kind of test applied. The trend between concentration of ENPs and effect depended on the method used and kind of ENPs. For most nanoparticles (despite of the method used), the differences in phytotoxicity between nano and bulk particles were observed. Depending on the kind of ENPs, their phytotoxicity differs between water and soil. ZnO (nano and bulk) and nano-Ni were more toxic in soil than in water. For TiO₂ and bulk-Ni, reverse trend was observed. A different method of ENP application to soil differently affects the phytotoxicity.
Afficher plus [+] Moins [-]Influence of UV radiation on chlorophyll, and antioxidant enzymes of wetland plants in different types of constructed wetland Texte intégral
2014
Xu, Defu | Wu, Yinjuan | Li, Yingxue | Howard, Alan | Jiang, Xiaodong | Guan, Yidong | Gao, Yongxia
Influence of UV radiation on chlorophyll, and antioxidant enzymes of wetland plants in different types of constructed wetland Texte intégral
2014
Xu, Defu | Wu, Yinjuan | Li, Yingxue | Howard, Alan | Jiang, Xiaodong | Guan, Yidong | Gao, Yongxia
A surface- and vertical subsurface-flow-constructed wetland were designed to study the response of chlorophyll and antioxidant enzymes to elevated UV radiation in three types of wetland plants (Canna indica, Phragmites austrail, and Typha augustifolia). Results showed that (1) chlorophyll content of C. indica, P. austrail, and T. augustifolia in the constructed wetland was significantly lower where UV radiation was increased by 10 and 20 % above ambient solar level than in treatment with ambient solar UV radiation (p < 0.05). (2) The malondialdehyde (MDA) content, guaiacol peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities of wetland plants increased with elevated UV radiation intensity. (3) The increased rate of MDA, SOD, POD, and CAT activities of C. indica, P. australis, and T. angustifolia by elevated UV radiation of 10 % was higher in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. The sensitivity of MDA, SOD, POD, and CAT activities of C. indica, P. austrail, and T. augustifolia to the elevated UV radiation was lower in surface-flow-constructed wetland than in the vertical subsurface-flow-constructed wetland, which was related to a reduction in UV radiation intensity through the dissolved organic carbon and suspended matter in the water. C. indica had the highest SOD and POD activities, which implied it is more sensitive to enhanced UV radiation. Therefore, different wetland plants had different antioxidant enzymes by elevated UV radiation, which were more sensitive in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland.
Afficher plus [+] Moins [-]Influence of UV radiation on chlorophyll, and antioxidant enzymes of wetland plants in different types of constructed wetland Texte intégral
2014
Xu, Defu | Wu, Yinjuan | Li, Yingxue | Howard, Alan | Jiang, Xiaodong | Guan, Yidong | Gao, Yongxia
A surface- and vertical subsurface-flow-constructed wetland were designed to study the response of chlorophyll and antioxidant enzymes to elevated UV radiation in three types of wetland plants (Canna indica, Phragmites austrail, and Typha augustifolia). Results showed that (1) chlorophyll content of C. indica, P. austrail, and T. augustifolia in the constructed wetland was significantly lower where UV radiation was increased by 10 and 20 % above ambient solar level than in treatment with ambient solar UV radiation (p < 0.05). (2) The malondialdehyde (MDA) content, guaiacol peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities of wetland plants increased with elevated UV radiation intensity. (3) The increased rate of MDA, SOD, POD, and CAT activities of C. indica, P. australis, and T. angustifolia by elevated UV radiation of 10 % was higher in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. The sensitivity of MDA, SOD, POD, and CAT activities of C. indica, P. austrail, and T. augustifolia to the elevated UV radiation was lower in surface-flow-constructed wetland than in the vertical subsurface-flow-constructed wetland, which was related to a reduction in UV radiation intensity through the dissolved organic carbon and suspended matter in the water. C. indica had the highest SOD and POD activities, which implied it is more sensitive to enhanced UV radiation. Therefore, different wetland plants had different antioxidant enzymes by elevated UV radiation, which were more sensitive in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland.
Afficher plus [+] Moins [-]A review of plant–pharmaceutical interactions: from uptake and effects in crop plants to phytoremediation in constructed wetlands Texte intégral
2014
Carvalho, Pedro N. | Basto, M. Clara P. | Almeida, C. Marisa R. | Brix, Hans
Pharmaceuticals are commonly found both in the aquatic and the agricultural environments as a consequence of the human activities and associated discharge of wastewater effluents to the environment. The utilization of treated effluent for crop irrigation, along with land application of manure and biosolids, accelerates the introduction of these compounds into arable lands and crops. Despite the low concentrations of pharmaceuticals usually found, the continuous introduction into the environment from different pathways makes them ‘pseudo-persistent’. Several reviews have been published regarding the potential impact of veterinary and human pharmaceuticals on arable land. However, plant uptake as well as phytotoxicity data are scarcely studied. Simultaneously, phytoremediation as a tool for pharmaceutical removal from soils, sediments and water is starting to be researched, with promising results. This review gives an in-depth overview of the phytotoxicity of pharmaceuticals, their uptake and their removal by plants. The aim of the current work was to map the present knowledge concerning pharmaceutical interactions with plants in terms of uptake and the use of plant-based systems for phytoremediation purposes.
Afficher plus [+] Moins [-]Multivariate relationships between molecular descriptors and isomer distribution patterns of PCBs formed during household waste incineration Texte intégral
2014
Jansson, Stina | Grabic, Roman
The congener-specific concentrations of mono- to deca-chlorinated biphenyls (PC₁–₁₀B) in post-combustion zone flue gases from a laboratory-scale fluidized bed reactor were evaluated and correlated with a set of physicochemical properties and chlorine substitution descriptors. The objective was to identify parameters that affect post-combustion zone polychlorinated biphenyl (PCB) formation and interpreting observed correlations by using principal component analysis (PCA), and bidirectional orthogonal projections to latent structures (O2PLS). Both physicochemical variables and chlorine substitution descriptors were shown to have significant effects on the PCB congener distribution; however, the physicochemical descriptors were more influential in all-homologue models, whereas the chlorine substitution descriptors had a greater impact in single-homologue models, which suggests that PCB formation in general may be under thermodynamic control, whereas the distribution of isomers within homologues is more sensitive to chlorine substitution parameters. The EHOMO and ELUMO variables notably influenced both the PCA and the O2PLS models, which indicate that reactivity and polarization in the molecular structures of the PCBs is of importance.
Afficher plus [+] Moins [-]Source apportionment of PAHs and n-alkanes in respirable particles in Tehran, Iran by wind sector and vertical profile Texte intégral
2014
Moeinaddini, Mazaher | Esmaili Sari, Abbas | Riyahi bakhtiari, Alireza | Chan, Andrew Yiu-Chung | Taghavi, Seyed Mohammad | Hawker, Darryl | Connell, Des
The vertical concentration profiles and source contributions of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in respirable particle samples (PM₄) collected at 10, 100, 200 and 300-m altitude from the Milad Tower of Tehran, Iran during fall and winter were investigated. The average concentrations of total PAHs and total n-alkanes were 16.7 and 591 ng/m³, respectively. The positive matrix factorization (PMF) model was applied to the chemical composition and wind data to apportion the contributing sources. The five PAH source factors identified were: ‘diesel’ (56.3 % of total PAHs on average), ‘gasoline’ (15.5 %), ‘wood combustion, and incineration’ (13 %), ‘industry’ (9.2 %), and ‘road soil particle’ (6.0 %). The four n-alkane source factors identified were: ‘petrogenic’ (65 % of total n-alkanes on average), ‘mixture of petrogenic and biomass burning’ (15 %), ‘mixture of biogenic and fossil fuel’ (11.5 %), and ‘biogenic’ (8.5 %). Source contributions by wind sector were also estimated based on the wind sector factor loadings from PMF analysis. Directional dependence of sources was investigated using the conditional probability function (CPF) and directional relative strength (DRS) methods. The calm wind period was found to contribute to 4.4 % of total PAHs and 5.0 % of total n-alkanes on average. Highest average concentrations of PAHs and n-alkanes were found in the 10 and 100 m samples, reflecting the importance of contributions from local sources. Higher average concentrations in the 300 m samples compared to those in the 200 m samples may indicate contributions from long-range transport. The vertical profiles of source factors indicate the gasoline and road soil particle-associated PAHs, and the mixture from biogenic and fossil fuel source-associated n-alkanes were mostly from local emissions. The smaller average contribution of diesel-associated PAHs in the lower altitude samples also indicates that the restriction of diesel-fueled vehicle use in the central area of Tehran has been effective in reducing the PAHs concentration.
Afficher plus [+] Moins [-]Estimated crop yield losses due to surface ozone exposure and economic damage in India Texte intégral
2014
Debaje, S. B.
In this study, we estimate yield losses and economic damage of two major crops (winter wheat and rabi rice) due to surface ozone (O₃) exposure using hourly O₃concentrations for the period 2002–2007 in India. This study estimates crop yield losses according to two indices of O₃exposure: 7-h seasonal daytime (0900–1600 hours) mean measured O₃concentration (M7) and AOT40 (accumulation exposure of O₃concentration over a threshold of 40 parts per billion by volume during daylight hours (0700–1800 hours), established by field studies. Our results indicate that relative yield loss from 5 to 11 % (6–30 %) for winter wheat and 3–6 % (9–16 %) for rabi rice using M7 (AOT40) index of the mean total winter wheat 81 million metric tons (Mt) and rabi rice 12 Mt production per year for the period 2002–2007. The estimated mean crop production loss (CPL) for winter wheat are from 9 to 29 Mt, account for economic cost loss was from 1,222 to 4,091 million US$ annually. Similarly, the mean CPL for rabi rice are from 0.64 to 2.1 Mt, worth 86–276 million US$. Our calculated winter wheat and rabi rice losses agree well with previous results, providing the further evidence that large crop yield losses occurring in India due to current O₃concentration and further elevated O₃concentration in future may pose threat to food security.
Afficher plus [+] Moins [-]Enhanced bioremediation of oil-polluted, hypersaline, coastal areas in Kuwait via vitamin-fertilization Texte intégral
2014
Al-Mailem, Dina M. | Eliyas, Mohamed | Raḍwān, Samīr Muḥammad
There is no research published sofar on managements that could bioremediate hypersaline soils and water polluted with hydrocarbons. The objective of this study was to assess the effect of vitamin amendment on hydrocarbon removal by microorganisms indigenous to such hypersaline environments. We used in this study ten hydrocarbonoclastic bacterial species and five archaeal species that had been isolated by the conventional plating method on media containing oil as a sole carbon source, from a hypersaline (3–4 M NaCl) coastal area in Kuwait, and characterized by sequencing of their 16S rRNA coding genes. The oil and pure hydrocarbon consumption was measured by gas–liquid chromatography. The oil and pure hydrocarbon consumption potential of all microorganisms in media with hypersalinity was enhanced by vitamin fertilization. This was true for individual microorganisms in pure cultures as well as for microbial consortia in hypersaline soil and water samples used as inocula. Most effective vitamins were thiamin, pyridoxine and vitamin B₁₂. Vitamin fertilization using vitamin rich wastes or byproducts could be an effective practice for enhancing bioremediation of oil contaminated hypersaline environments.
Afficher plus [+] Moins [-]Assessing the hydrocarbon degrading potential of indigenous bacteria isolated from crude oil tank bottom sludge and hydrocarbon-contaminated soil of Azzawiya oil refinery, Libya Texte intégral
2014
Mansur, Abdulatif A. | Adetutu, Eric M. | Kadali, Krishna K. | Morrison, Paul D. | Nurulita, Yuana | Ball, A. S.
The disposal of hazardous crude oil tank bottom sludge (COTBS) represents a significant waste management burden for South Mediterranean countries. Currently, the application of biological systems (bioremediation) for the treatment of COTBS is not widely practiced in these countries. Therefore, this study aims to develop the potential for bioremediation in this region through assessment of the abilities of indigenous hydrocarbonoclastic microorganisms from Libyan Hamada COTBS for the biotreatment of Libyan COTBS-contaminated environments. Bacteria were isolated from COTBS, COTBS-contaminated soil, treated COTBS-contaminated soil, and uncontaminated soil using Bushnell Hass medium amended with Hamada crude oil (1 %) as the main carbon source. Overall, 49 bacterial phenotypes were detected, and their individual abilities to degrade Hamada crude and selected COBTS fractions (naphthalene, phenanthrene, eicosane, octadecane and hexane) were evaluated using MT2 Biolog plates. Analyses using average well colour development showed that ~90 % of bacterial isolates were capable of utilizing representative aromatic fractions compared to 51 % utilization of representative aliphatics. Interestingly, more hydrocarbonoclastic isolates were obtained from treated contaminated soils (42.9 %) than from COTBS (26.5 %) or COTBS-contaminated (30.6 %) and control (0 %) soils. Hierarchical cluster analysis (HCA) separated the isolates into two clusters with microorganisms in cluster 2 being 1.7- to 5-fold better at hydrocarbon degradation than those in cluster 1. Cluster 2 isolates belonged to the putative hydrocarbon-degrading genera; Pseudomonas, Bacillus, Arthrobacter and Brevundimonas with 57 % of these isolates being obtained from treated COTBS-contaminated soil. Overall, this study demonstrates that the potential for PAH degradation exists for the bioremediation of Hamada COTBS-contaminated environments in Libya. This represents the first report on the isolation of hydrocarbonoclastic bacteria from Libyan COTBS and COTBS-contaminated soil.
Afficher plus [+] Moins [-]Degradation of PAHs in soil by Lasiodiplodia theobromae and enhanced benzo[a]pyrene degradation by the addition of Tween-80 Texte intégral
2014
Wang, Cuiping | Liu, Haibin | Li, Jing | Sun, Hongwen
Benzo[a]pyrene (BaP), a five-ring polycyclic aromatic hydrocarbon (PAH), which has carcinogenic potency, is highly recalcitrant and resistant to microbial degradation. A novel fungus, Lasiodiplodia theobromae (L. theobromae), which can degrade BaP as a sole carbon source in liquid, was isolated in our laboratory. To prompt the further application of L. theobromae in remediation of sites polluted by BaP and other PAHs, the present study was targeted toward the removal of BaP and PAHs from soil by L. theobromae. The degradation of BaP by L. theobromae was studied using a soil spiked with 50 mg/kg BaP. L. theobromae could remove 32.1 % of the BaP after 35 days of cultivation. Phenanthrene (PHE) inhibited BaP degradation as a competitive substrate. The tested surfactants enhanced BaP degradation in soil by different extents, and a removal rate of 92.1 % was achieved at a Tween-80 (TW-80) concentration of 5 g/kg. It was revealed that TW-80 could not only enhance BaP bioavailability by increasing its aqueous solubility and decreasing the size of its colloid particles but also increase enzyme secretion from L. theobromae and the population of L. theobromae. Moreover, ergosterol content together with the biomass C indicated the increase in L. theobromae biomass during the BaP biodegradation process in soils. Finally, a soil from a historically PAH-contaminated field at Beijing Coking Plant in China was tested to assess the feasibility of applying L. theobromae in the remediation of polluted sites. The total removal rate of PAHs by L. theobromae was 53.3 %, which is 13.1 % higher than that by Phanerochaete chrysosporium (P. chrysosporium), an effective PAH degrader. The addition of TW-80 to the field soil further enhanced PAH degradation to 73.2 %. Hence, L. theobromae is a promising novel strain to be implemented in the remediation of soil polluted by PAHs.
Afficher plus [+] Moins [-]Examination of oxygen release from plants in constructed wetlands in different stages of wetland plant life cycle Texte intégral
2014
Zhang, Jian | Wu, Haiming | Hu, Zhen | Liang, Shuang | Fan, Jinlin
The quantification of oxygen release by plants in different stages of wetland plant life cycle was made in this study. Results obtained from 1 year measurement in subsurface wetland microcosms demonstrated that oxygen release from Phragmites australis varied from 108.89 to 404.44 mg O₂/m²/d during the different periods from budding to dormancy. Plant species, substrate types, and culture solutions had a significant effect on the capacity of oxygen release of wetland plants. Oxygen supply by wetland plants was estimated to potentially support a removal of 300.37 mg COD/m²/d or 55.87 mg NH₄-N/m²/d. According to oxygen balance analysis, oxygen release by plants could provide 0.43–1.12 % of biochemical oxygen demand in typical subsurface-flow constructed wetlands (CWs). This demonstrates that oxygen release of plants may be a potential source for pollutants removal especially in low-loaded CWs. The results make it possible to quantify the role of plants in wastewater purification.
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